JP5299474B2 - X-ray diffraction measurement device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely measure diffraction rings without reference to the intensity of diffracted X rays. <P>SOLUTION: While rotating an irradiation position of laser light around the center of an imaging plate 28 and changing it in a radial direction, a controller CT makes the intensity of the laser light or an amplification factor for a light reception signal equal at the same angle of rotation of the imaging plate 28, and changes the intensity of the laser light or the amplification factor for the light reception signal each time the imaging plate 28 is changed at intervals of a predetermined angle. The controller CT acquires the light reception signal in sequence each time the angle of rotation of the imaging plate 28 changes at the intervals of the predetermined angle from a reference angle, detects a radial position where the light reception signal has a peak of level over one round, and sets an optimum intensity of the laser light or an optimum amplification factor for the light reception signal on the basis of the light reception signal at detected radial positions over the one round. <P>COPYRIGHT: (C)2013,JPO&amp;INPIT

Description

  The present invention relates to an X-ray diffraction measurement apparatus that irradiates a measurement object with X-rays, receives X-rays diffracted by the measurement object on a light receiving surface, and measures a diffraction ring formed on the light receiving surface.

  Conventionally, the residual stress of a measurement object is often measured by X-ray diffraction. In addition, as shown in the following Patent Document 1, the ratio between the body-centered cubic lattice structure (hereinafter referred to as ferrite) and the face-centered cubic lattice structure (hereinafter referred to as austenite), which is the arrangement structure of most of the iron elements Is also measured by measuring the diffraction integral intensity due to ferrite and the diffraction integral intensity due to austenite when the measurement object is X-ray diffracted. Since the properties of iron change when the proportion of austenite in iron changes, this proportion has the most desirable ratio for each application of iron. And since this ratio changes depending on the conditions when heating and cooling iron, it is important to keep the manufacturing conditions constant, but it is also important to accurately measure the ratio of austenite in the manufactured iron It is.

  As an X-ray diffraction measurement apparatus, there is an apparatus disclosed in Patent Document 2 below as an apparatus that can be miniaturized and can shorten an X-ray irradiation time. This apparatus irradiates a measurement object with X-rays at a predetermined angle, receives X-rays diffracted by the measurement object (hereinafter referred to as diffracted X-rays) with a photosensitive imaging plate, and performs imaging. The residual stress of the measurement object is calculated by the cos α method for analyzing the shape of an annular X-ray diffraction image (hereinafter referred to as a diffraction ring) formed on the plate. The following Patent Document 2 only describes the determination of the residual stress of the measurement object. However, even with the X-ray diffraction measurement apparatus shown in Patent Document 2, the diffraction integration by ferrite and austenite in the radial direction of the diffraction ring is described. By measuring the strength, the proportion of austenite in iron can be measured. In Patent Document 2 below, two methods are shown for measuring the shape of the diffraction ring. One method is to scan the imaging plate with excitation light such as He-Ne laser light, detect the intensity of light generated by the stimulated emission from the diffraction ring by a photomultiplier tube, and detect an image of the diffraction ring. How to get. Another method is a method in which a diffracted X-ray is received by an X-ray CCD, and an image of a diffraction ring is obtained from a signal output from each pixel of the X-ray CCD.

Japanese Patent Laid-Open No. 11-230921 JP-A-2005-241308

  However, in the above two methods of Patent Document 2, since the diffraction X-ray intensity of ferrite is strong, an image of a diffraction ring by ferrite can be clearly obtained. The intensity of the diffracted X-ray is so weak that an image of a diffractive ring made of austenite cannot be clearly obtained. In other words, the shape of the diffraction ring made of ferrite and the diffraction integral intensity of ferrite can be obtained with high accuracy, but the shape of the diffraction ring made of austenite and the diffraction integral intensity of austenite cannot be obtained with high accuracy. Further, even if the object to be measured is a substance other than iron, there is a problem that the shape of the diffraction ring and the diffraction integral intensity cannot be obtained with high accuracy if the intensity of the diffracted X-ray is weak.

  The present invention has been made in order to solve the above-described problems, and its purpose is to irradiate a measurement object with X-rays, receive X-rays diffracted by the measurement object with a light-receiving surface, and receive the light-receiving surface with diffraction X-rays An X-ray diffractometer for measuring a diffractive ring formed on the X-ray diffractometer is provided that can accurately measure the diffractive ring regardless of the intensity of the diffracted X-ray. In the description of each constituent element of the present invention below, in order to facilitate understanding of the present invention, reference numerals of corresponding portions of the embodiments described later are shown in parentheses, but each constituent element of the present invention is described. Should not be construed as limited to the configuration of the corresponding parts indicated by the reference numerals of this embodiment.

  In order to achieve the above object, the first invention provides an X-ray emitter (13) that emits X-rays toward an object to be measured and a table (27) in which a through-hole that allows X-rays to pass is formed in the center. And a diffracted light receiver (28) that is fixed to the table and has a light receiving surface for receiving diffracted light of X-rays diffracted by the measurement object, and records a diffracted ring that is an image of the diffracted light; A laser light source that emits laser light and a photodetector that receives the laser light, irradiates the light receiving surface of the diffracted light receiver with the laser light, and receives the light emitted from the diffracted light receiver by the laser light irradiation A laser detection device (PUH) that outputs a received light signal according to the received light intensity, a rotating means (24, 25) for rotating the table around the central axis of the through hole, and a reference position for rotating the table by the rotating means Rotation angle from Rotation angle detection circuit (26) for detecting, and moving means (15, 17, 18, 22) for moving the table relative to the laser detection device in a direction parallel to the light receiving surface of the diffracted light receiver. A position detection circuit (21) for detecting the moving position of the table by the moving means, a laser drive circuit (34) capable of driving and controlling the laser light source and changing the intensity of the laser light emitted from the laser light source, and a photo detector And an amplification circuit (44) for amplifying and outputting the received light signal, and irradiating the measurement object from the X-ray emitter and recording the X-ray diffracted by the measurement object on the diffracted light receiver. In an X-ray diffraction measurement apparatus for measuring a diffraction ring, a laser emitted from a laser detection apparatus by controlling a rotating means and a moving means to rotate and move a diffracted light receiver on which the diffraction ring is recorded The irradiation position control means (CT, S208, S210, S218) for rotating the irradiation position in the diffracted light receiver around the center of the diffracted light receiver and changing the radial distance from the center, and the irradiation position control means The rotation angle of the table detected by the rotation angle detection circuit while rotating the irradiation position of the laser beam in the diffracted light receiver around the center of the diffracted light receiver and changing the radial distance from the center The laser drive circuit is controlled so that the intensity of the laser beam changes at the same rotation angle, and the intensity of the laser beam changes every time the table rotation angle changes by a predetermined angle from the same rotation angle. The laser intensity control means (CT, S222 to S228) and the table rotation angle change by a predetermined angle. A light reception signal acquisition means (CT, S230) for acquiring a plurality of light reception signals respectively corresponding to a plurality of irradiation positions of the laser light distributed in the radial direction of the diffracted light receiver; A plurality of light reception signals which are obtained by the light reception signal acquisition means and have the same table rotation angle and respectively correspond to a plurality of irradiation positions of the laser light distributed in the radial direction of the diffracted light receiver Among them, the peak detecting means (CT, S314, S316) for detecting the radial position where the magnitude of the received light signal reaches a peak for one round at a predetermined angle, and the diameter for one round detected by the peak detecting means. Among the received light signals acquired by the received light signal acquisition means at the directional position, the optimum laser intensity that sets the intensity of the laser beam with the optimum magnitude of the received light signal as the optimum laser intensity In the provision and constant means (S244).

  In the first invention configured as described above, the laser intensity control means causes the irradiation position control means to rotate the irradiation position of the laser light in the diffracted light receiver around the center of the diffracted light receiver and from the center. In the state where the radial distance is changed, when the table rotation angle detected by the rotation angle detection circuit is the same rotation angle, the laser beam intensity is made the same, and the table rotation angle is the same. The intensity of the laser beam is changed every time the rotation angle is changed by a predetermined angle, and the received light signal acquisition means is a received light signal from the amplification circuit in each state where the rotation angle of the table is changed by the predetermined angle. A plurality of received light signals respectively corresponding to a plurality of irradiation positions of laser light distributed in the radial direction of the light receiver are acquired. Using this acquired light reception signal, the peak detection means makes one round of the radial position where the magnitude of the light reception signal peaks among the plurality of light reception signals distributed in the radial direction of the diffracted light receiver. By detecting, the diffraction ring which is the image of the diffraction X-ray recorded on the diffracted light receiver is detected. Then, the optimum laser intensity determining means is the laser beam whose magnitude of the received light signal is optimum among the received light signals acquired by the received light signal acquiring means at the radial position for one round detected by the peak detecting means. Set the intensity as the optimum laser intensity. In this way, the radial position where the magnitude of the received signal reaches a peak is detected for one round at a predetermined angle, and the optimal intensity of the laser beam is set using the received light signal at the radial position for one round. Therefore, the optimum laser beam intensity can be easily set. As a result, according to the first invention, even when the intensity of the diffracted X-ray is weak, the laser light intensity can be set so that the peak value of the received light signal corresponding to the intensity of the diffracted X-ray becomes large. The diffraction ring by the diffraction X-ray can be measured with high accuracy, and the shape of the diffraction ring, the diffraction integral intensity, etc. can be obtained with high accuracy.

  The second invention is the same X-ray emitter (13), table (27), diffracted light receiver (28), laser detector (PUH), rotating means (24, 25) as in the first invention. ), Rotation angle detection circuit (26), movement means (15, 17, 18, 22), position detection circuit (21), irradiation position control means (CT, S210, S252, S256), received light signal acquisition means (CT, S270) and peak detection means (CT, S314, S316) and drive control of the laser light source instead of the laser drive circuit, amplification circuit, laser intensity control means and optimum laser intensity setting means in the first invention. A laser drive circuit (34), an amplification circuit (44) capable of amplifying and outputting a light reception signal from the photodetector and changing the amplification factor of the light reception signal, and an irradiation position control means The rotation angle of the table detected by the rotation angle detection circuit while the irradiation position of the laser beam in the diffracted light receiver is rotated around the center of the diffracted light receiver and the radial distance from the center is changed. The amplification circuit of the received light signal is made the same when the rotation angle is the same, and the amplification circuit of the received light signal is changed every time the rotation angle of the table changes from the same rotation angle by a predetermined angle. Among the received light signals acquired by the gain control means (CT, S260 to S266) to be controlled and the received light signal acquiring means at the radial position for one round detected by the peak detecting means, the magnitude of the received light signal is An optimum amplification factor setting means (CT, S284) for setting the optimum amplification factor of the received light signal as the optimum amplification factor is provided.

  Also in the second aspect of the invention, the radial position where the magnitude of the received light signal reaches a peak is detected by one predetermined angle at a time, and the optimal received light signal is detected by using the received light signal at the radial position for one turn. Since the amplification factor is set, the optimum amplification factor of the received light signal can be easily set. As a result, according to the second invention as well, even when the intensity of the diffracted X-ray is weak, the amplification factor of the received light signal can be set so that the peak value of the received light signal corresponding to the intensity of the diffracted X-ray becomes large. Therefore, it is possible to accurately measure the diffraction ring by diffracted X-rays, and to accurately determine the shape of the diffraction ring, the diffraction integral intensity, and the like.

  The third invention is the same X-ray emitter (13), table (27), diffracted light receiver (28), laser detector (PUH), rotating means (24, 25) as in the first invention. ), A rotation angle detection circuit (26), a moving means (15, 17, 18, 22), a position detection circuit (21), and a laser drive circuit (34), and in place of the amplification circuit in the first invention. And an amplification circuit (44) capable of amplifying and outputting the light reception signal from the photodetector and changing the gain of the light reception signal. Further, the third invention is the first irradiation position control means (CT, similar to the irradiation position control means, laser intensity control means, received light signal acquisition means, peak detection means and optimum laser intensity setting means of the first invention. S208, S210, S218), laser intensity control means (CT, S222 to S228), first received light signal acquisition means (CT, S230), first peak detection means (CT, S314, S316) and optimum laser intensity setting means ( CT, S244) and the first irradiation position control means (CT, S244) similar to the irradiation position control means, amplification factor control means, received light signal acquisition means, peak detection means and optimum amplification factor setting means of the second invention. S210, S252, S256), gain control means (CT, S260-S268), second received light signal acquisition means (CT, S270), second peak detection And a means (CT, S314, S316) and the optimum gain setting means (CT, S284). In this case, the laser intensity control means adjusts the intensity of the laser beam when the rotation angle of the table detected by the rotation angle detection circuit is the same rotation angle while keeping the gain of the received light signal constant. The laser drive circuit is controlled so that the intensity of the laser beam changes every time the table rotation angle changes by a predetermined angle from the same rotation angle, and the amplification factor control means is an optimum laser intensity setting means. When the table rotation angle detected by the rotation angle detection circuit is the same rotation angle while keeping the laser beam intensity at the optimum laser intensity set by the The amplifier circuit is controlled so that the amplification factor of the received light signal changes every time the rotation angle changes from the same rotation angle by a predetermined angle. After the setting of the intensity of a laser beam, and sets the gain of the optimum reception signal.

  In the third invention configured as described above, the radial position at which the signal magnitude reaches a peak is detected for one round at a predetermined angle, and the light receiving signal at the radial position for one round is used to obtain the optimum position. Since the intensity of the laser beam and the amplification factor of the received light signal are set, the optimum intensity of the laser beam and the amplification factor of the received light signal can be set easily. Therefore, also in the third invention, even when the intensity of the diffracted X-ray is weak, the intensity of the laser beam and the amplification factor of the received light signal are set so that the peak value of the received light signal corresponding to the intensity of the diffracted X-ray is increased. Therefore, it is possible to accurately measure the diffraction ring by diffracted X-rays, and to accurately determine the shape of the diffraction ring, the diffraction integral intensity, and the like. According to the third invention, the intensity of the laser beam is set before the amplification factor of the received light signal. In this case, since the change width of the intensity of the laser beam is smaller than the change width of the gain of the received light signal, the peak value can be set to a value in the vicinity of the largest value, and the signal intensity curve in the radial direction of the diffraction ring The noise component in can be reduced. That is, contrary to the third aspect of the present invention, even if the amplification factor of the signal is first changed to a value in the vicinity of the maximum peak value and the amplification factor is set optimally, The value saturates and does not change. On the other hand, if the optimum value of the intensity of the laser beam is determined first as in the third invention, this is not the case, and the optimum signal intensity is determined and the signal level is optimized (maximum ) Can be set. As a result, the S / N ratio of the received light signal is also good.

  In the first and third aspects of the invention, the optimum laser intensity setting means determines the magnitude of the received light signal with respect to a change in the intensity of the laser light in a state where the laser intensity control means sequentially increases the intensity of the laser light. The amount of change is calculated, and when the amount of change in the magnitude of the received light signal does not reach a predetermined value, the intensity of the laser beam before the change is set as the optimum laser intensity, and the amount of change in the magnitude of the received light signal If the maximum value of the increased laser light intensity is not set to the predetermined value, the maximum value of the increased laser light intensity may be set as the optimum laser intensity. In the second and third aspects of the invention, the optimum amplification factor setting means is the magnitude of the light reception signal with respect to the change in the amplification factor of the light reception signal in a state where the amplification factor control means sequentially increases the amplification factor of the light reception signal. The amount of change in the light reception signal is calculated, and when the amount of change in the light reception signal does not reach a predetermined value, the amplification factor of the light reception signal before the change is set as the optimum amplification factor. When there is no case where the change amount does not reach the predetermined value, the maximum value of the increased amplification factor of the received light signal may be set as the optimum amplification factor.

  As described above, when the amount of change in the magnitude of the received light signal does not reach a predetermined value, the intensity of the laser beam before the change or the amplification factor of the received light signal is set as the optimum laser intensity or optimum amplification factor. Accordingly, the peak value can be set to a value in the vicinity of the largest value while avoiding saturation of the peak value. As a result, the noise component of the received light signal of the laser beam due to the reflection of the part other than the diffraction ring can be suppressed, the diffraction ring by X-ray diffraction can be measured more accurately, and the shape of the diffraction ring, the diffraction integral intensity, etc. can be further improved. The accuracy can be obtained. In particular, when setting both the intensity of the laser beam and the amplification factor of the received light signal as in the third aspect of the invention, if one is set to a large value, the peak value is saturated by the optimum value of the one. While the other may not be changeable, it is easier to avoid such a situation.

  In the present invention, when the measurement object is iron, the peak detected by the peak detection means, the first peak detection means, or the second peak detection means may be due to a ferrite diffraction ring. . According to this, if the peak value is set to the maximum value in the diffraction ring of ferrite, the peak value can be sufficiently increased even in the diffraction ring by austenite, and the shape of the diffraction ring by austenite and the diffraction by austenite The integrated intensity can be obtained with high accuracy.

  Furthermore, in carrying out the present invention, the present invention is not limited to the invention of the X-ray diffraction measurement device, but can also be implemented as an invention of an X-ray diffraction measurement method.

1 is an overall schematic diagram of an X-ray diffraction measurement apparatus according to an embodiment of the present invention. It is the enlarged view to which the main-body part of the X-ray-diffraction measuring apparatus of FIG. 1 was expanded. It is explanatory drawing explaining the relationship between the distance from an imaging plate to a measuring object, and the light reception position in a light reception sensor. It is a flowchart which shows the diffraction ring imaging program performed by the controller of FIG. It is a flowchart which shows the first half part of the optimal setting program performed by the controller of FIG. It is a flowchart which shows the second half part of the said optimal setting program. It is a flowchart which shows the peak detection program performed by the controller of FIG. It is a flowchart which shows the first half part of the diffraction ring reading program performed by the controller of FIG. It is a flowchart which shows the latter half part of the said diffraction ring reading program. It is a flowchart which shows the diffraction ring deletion program performed by the controller of FIG. It is explanatory drawing explaining the diffraction ring imaged by the imaging plate. It is a figure for demonstrating the relationship between the movement distance from the movement limit position of an imaging plate, and the radial direction distance (radius value) of the irradiation position of the laser beam in an imaging plate. It is explanatory drawing explaining the locus | trajectory of a reading point. (A) is explanatory drawing for demonstrating the change of the intensity | strength of a laser beam, (B) is explanatory drawing for demonstrating the change of an amplification factor. It is the graph which showed an example of the light reception curve, in order to explain the peak of signal intensity. (A) is an explanation for explaining the first method for determining the optimum laser light intensity and amplification factor, and (B) is for explaining the second method for determining the optimum laser light intensity and amplification factor. It is explanatory drawing for. It is a graph which shows the change of the signal strength with respect to a radial position.

  A configuration of an X-ray diffraction measurement apparatus according to an embodiment of the present invention will be described with reference to FIGS. This X-ray diffraction measurement apparatus irradiates the measurement object OB with X-rays in order to evaluate the characteristics of the measurement object OB, and also forms a diffraction ring formed by diffracted X-rays from the measurement object OB by the irradiation. And the intensity of the diffracted X-ray for each diffraction ring. This X-ray diffraction measurement apparatus has a frame FR formed in a box shape, and support legs 11 are extended downward from corners of the bottom surface of the frame FR. That is, the bottom surface of the frame FR is located above the installation surface FL of the X-ray diffraction measurement apparatus. A lift 12 is provided below the frame FR. The elevator 12 has an elevator stage 12a for fixing the measurement object OB. The elevating stage 12a can be moved up and down. An opening is provided in the bottom surface of the frame FR, which is located above the elevator 12, and the fixed measurement object OB is carried into the frame FR by raising the elevating stage 12 a. Can do.

  An X-ray emitter 13 that emits X-rays, which is controlled by the X-ray control circuit 14, is fixed to the upper part of the frame FR. The direction of the exit of the X-ray emitter 13 so that the optical axis of the X-ray emitted from the X-ray emitter 13 and the normal line of the measurement object OB form a predetermined angle θ (for example, 30 °). Is set.

  The X-ray control circuit 14 is controlled by a controller CT, which will be described later, and controls the drive current and drive voltage supplied to the X-ray emitter 13 so that X-rays with a certain intensity are emitted from the X-ray emitter 13. . In addition, the X-ray emitter 13 includes a cooling device (not shown), and the X-ray control circuit 14 also controls a drive signal supplied to the cooling device. Thereby, the temperature of the X-ray emitter 13 is kept constant.

  A moving stage 15 is provided below the X-ray emitter 13. The moving stage 15 can be moved in a direction perpendicular to the optical axis of the X-rays emitted from the X-ray emitter 13 by the stage feeder 16. The stage feeding device 16 includes a screw rod 17 that is screwed into a nut (not shown) fixed to the moving stage 15, and a feed motor 18 that rotates the screw rod 17. The screw rod 17 extends in a direction perpendicular to the optical axis of the X-ray emitted from the X-ray emitter 13. One end portion of the screw rod 17 is connected to the output shaft of the feed motor 18 fixed to the frame FR, and the other end portion is rotatably supported by the bearing portion 19 fixed to the frame FR. The moving stage 15 is sandwiched between a pair of opposing plate-like guides 20 and 20 fixed to the frame FR, and is movable along the axial direction of the screw rod 17. That is, when the feed motor 18 is driven forward or backward, the rotational motion of the feed motor 18 is converted into the linear motion of the moving stage 15. An encoder 18 a is incorporated in the feed motor 18. The encoder 18 a outputs a pulse train signal that alternately switches between a high level and a low level to the position detection circuit 21 and the feed motor control circuit 22 every time the feed motor 18 rotates by a predetermined minute rotation angle.

  The position detection circuit 21 and the feed motor control circuit 22 start to operate in response to a command from the controller CT. Immediately after the start of measurement, the feed motor control circuit 22 drives the feed motor 18 to move the moving stage 15 to the feed motor 18 side. When the pulse signal output from the encoder 18a is not input, the position detection circuit 21 outputs a signal indicating that the movement stage 15 has reached the movement limit position to the feed motor control circuit 22, and sets the count value to “0”. Set. When the feed motor control circuit 22 receives a signal indicating that the movement limit position has been reached from the position detection circuit 21, the feed motor control circuit 22 stops outputting the drive signal to the feed motor 18. The above movement limit position is set as the origin position of the moving stage 15. Accordingly, the position detection circuit 21 outputs a position signal representing “0” when the movement stage 15 moves in the upper left direction in FIGS. 1 to 3 and reaches the movement limit position, and the movement stage 15 moves from the movement limit position. When moving in the lower right direction, a signal indicating the movement distance x from the movement limit position is output as a position signal.

  When the feed motor control circuit 22 receives a set value indicating the position of the moving stage 15 from the controller CT, the feed motor control circuit 22 drives the feed motor 18 in a forward or reverse direction according to the set value. The position detection circuit 21 counts the number of pulses of the pulse signal output from the encoder 18a. Then, the position detection circuit 21 calculates the current position (movement distance x from the movement limit position) of the movement stage 15 using the counted number of pulses, and outputs it to the controller CT and the feed motor control circuit 22. The feed motor control circuit 22 drives the feed motor 18 until the current position of the moving stage 15 input from the position detection circuit 21 matches the position of the moving destination input from the controller CT.

  Further, the feed motor control circuit 22 inputs a set value indicating the moving speed of the moving stage 15 from the controller CT. Then, the moving speed of the moving stage 15 is calculated using the number of pulses per unit time of the pulse signal input from the encoder 18a, and the calculated moving speed of the moving stage 15 becomes the moving speed input from the controller CT. The feed motor 18 is driven.

  The upper ends of the pair of guides 20 are connected by a plate-like upper wall 23. A through hole 23 a is provided in the upper wall 23, and a distal end portion of the emission port of the X-ray emitter 13 is inserted into the through hole 23 a. The positions of the X-ray emitter 13 and the moving stage 15 are set so that the tip of the emission port of the X-ray emitter 13 does not contact the moving stage 15.

  A spindle motor 24 is assembled to the moving stage 15. In the spindle motor 24, an encoder 24a similar to the encoder 18a is incorporated. That is, the encoder 24 a outputs a pulse train signal that alternately switches between a high level and a low level to the spindle motor control circuit 25 and the rotation angle detection circuit 26 every time the spindle motor 24 rotates by a predetermined minute rotation angle. Furthermore, the encoder 24a outputs an index signal that switches from a low level to a high level for a predetermined short period each time the spindle motor 24 makes one rotation, to the controller CT and the rotation angle detection circuit 26.

  The spindle motor control circuit 25 and the rotation angle detection circuit 26 start to operate in response to a command from the controller CT. The spindle motor control circuit 25 inputs a set value representing the rotational speed of the spindle motor 24 from the controller CT. Then, the rotational speed of the spindle motor 24 is calculated using the number of pulses per unit time of the pulse signal input from the encoder 24a, and the drive signal is converted to the spindle so that the calculated rotational speed becomes the rotational speed input from the controller CT. Supply to the motor 24. The rotation angle detection circuit 26 counts the number of pulses of the pulse train signal output from the encoder 24a, calculates the rotation angle of the spindle motor 24, that is, the rotation angle θp of the imaging plate 28 using the count value, and sends it to the controller CT. Output. Then, when the rotation angle detection circuit 26 receives the index signal output from the encoder 24a, the rotation angle detection circuit 26 sets the count value to “0”. That is, the position where the index signal is input is the position where the rotation angle is 0 °.

  A disk-shaped table 27 is fixed to the tip of the output shaft of the spindle motor 24. The center axis of the table 27 coincides with the center axis of the output shaft of the spindle motor 24. The table 27 has a protruding portion 27a that protrudes downward from the central portion of the lower surface, and a screw thread is formed on the outer peripheral surface of the protruding portion 27a. The central axis of the protrusion 27 a coincides with the central axis of the output shaft of the spindle motor 24. An imaging plate 28 is assembled on the lower surface of the table 27. The imaging plate 28 is a circular plastic film whose surface is coated with a phosphor. A through hole 28a is provided at the center of the imaging plate 28. The projection 27a is passed through the through hole 28a, and a nut-like fixture 29 is screwed into the projection 27a, whereby the imaging plate 28 is fixed. It is sandwiched between the tool 29 and the table 27 and fixed. The fixing tool 29 is a cylindrical member, and a thread corresponding to the thread of the protruding portion 27a is formed on the inner peripheral surface. The imaging plate 28 is driven by the feed motor 18 and moves together with the moving stage 15, the spindle motor 24 and the table 27 from the origin position to the diffraction ring imaging position for imaging the diffraction ring. The imaging plate 28 is driven by the spindle motor 24 to rotate and is driven by the feed motor 18 to read the imaged diffraction ring together with the moving stage 15, the spindle motor 24 and the table 27. Move within the diffractive ring erase region that erases the ring.

  Further, the moving stage 15, the output shaft of the spindle motor 24, the table 27, and the fixture 29 are provided with through holes through which the X-rays emitted from the X-ray emitter 13 pass. The center axis of these through holes and the rotation axis of the table 27 coincide. That is, when the central axis of these through holes and the optical axis of the X-ray emitted from the X-ray emitter 13 coincide with each other, the X-ray is irradiated onto the measurement object OB. Thus, the position of the imaging plate 28 when irradiating the measurement object OB with X-rays is the diffraction ring imaging position.

  A light receiving sensor 31 (for example, an X-ray CCD) including a plurality of light receiving elements that receive X-rays reflected by the measurement object OB is assembled below the feed motor 18. The light receiving sensor 31 is sufficiently separated from the measurement object OB and the imaging plate 28 toward the feed motor 18. Thus, when the imaging plate 28 is at the diffraction ring imaging position, the light receiving sensor 31 can directly receive the X-ray reflected by the measurement object OB. The light receiving surface of the light receiving sensor 31 is parallel to the upper surface of the measurement object OB. The light receiving position of the X-ray on the light receiving surface of the light receiving sensor 31 corresponds to the height of the measurement object OB as shown in FIG. In other words, this corresponds to the distance L between the imaging plate 28 and the measurement object OB. The light receiving sensor 31 outputs a light receiving signal received by each light receiving element to the sensor signal extracting circuit 32.

  The sensor signal extraction circuit 32 starts to operate in response to a command from the controller CT, calculates a peak position of the light receiving signal on the light receiving surface of the light receiving sensor 31 using the light receiving signal input from the light receiving sensor 31, and represents a light receiving position representing the light receiving position. The signal is output to the controller CT.

  A laser detection device PUH is assembled below the light receiving sensor 31. The laser detection device PUH irradiates the imaging plate 28 that images the diffraction ring with laser light, and detects the intensity of the light incident from the imaging plate 28. The laser detection device PUH is sufficiently separated from the measurement object OB and the imaging plate 28 toward the feed motor 18. That is, when the imaging plate 28 is at the diffraction ring imaging position, the X-ray diffracted by the measurement object OB is not blocked by the laser detection device PUH. The laser detection device PUH includes a laser light source 33, a collimating lens 35, a reflecting mirror 36, a polarizing beam splitter 37, a ¼ wavelength plate 38, and an objective lens 39.

  The laser light source 33 is controlled by the laser drive circuit 34 and emits laser light that irradiates the imaging plate 28.

  The laser drive circuit 34 is controlled by the controller CT and controls and supplies a drive signal so that laser light with a predetermined intensity is emitted from the laser light source 33. The laser drive circuit 34 receives the light reception signal output from the photodetector 51 described later, and controls the drive signal output to the laser light source 33 so that the intensity of the light reception signal becomes a predetermined intensity. Thereby, the intensity of the laser light applied to the imaging plate 28 is kept constant. The laser drive circuit 34 also includes a storage area for storing a plurality of switching pulse levels (corresponding to the pulse levels in FIG. 12A) supplied from the controller CT and one set pulse level. In response to this instruction, an output signal obtained by adding a switching pulse level or a set pulse level pulse to a low-level DC signal is output for a predetermined short time, and then the output signal is returned to a low-level DC signal.

  The collimating lens 35 converts the laser light emitted from the laser light source 33 into parallel light. The reflecting mirror 36 reflects the laser light converted into parallel light by the collimating lens 35 toward the polarization beam splitter 37. The polarization beam splitter 37 transmits most (for example, 95%) of the laser light incident from the reflecting mirror 36 as it is. The quarter wave plate 38 converts the laser light incident from the polarization beam splitter 37 from linearly polarized light to circularly polarized light. The objective lens 39 focuses the laser light incident from the quarter wavelength plate 38 on the surface of the imaging plate 28.

  A focus actuator 40 is assembled to the objective lens 39. The focus actuator 40 is an actuator that moves the objective lens 39 in the optical axis direction of the laser light. The objective lens 39 is positioned at the center of the movable range when the focus actuator 40 is not energized.

  When the laser beam condensed by the objective lens 39 is irradiated onto the surface of the imaging plate 28 where the diffraction ring is imaged, a photo-stimulated luminescence phenomenon occurs. That is, after imaging the diffraction ring and irradiating the imaging plate 28 with laser light, the phosphor of the imaging plate 28 is light corresponding to the intensity of the diffracted X-ray, and light having a wavelength shorter than the wavelength of the laser light. To emit. The reflected light of the laser beam irradiated and reflected on the imaging plate 28 and the light emitted from the phosphor pass through the objective lens 39 and the quarter wavelength plate 38 and are reflected by the polarization beam splitter 37. In the reflection direction of the polarization beam splitter 37, a condenser lens 41, a cylindrical lens 42, and a photodetector 43 are provided. The condensing lens 41 condenses the light incident from the polarization beam splitter 37 on the cylindrical lens 42. The cylindrical lens 42 causes astigmatism in the transmitted light. The photodetector 43 is composed of four divided light receiving elements composed of four light receiving elements of the same square shape divided by dividing lines, and the light incident on the light receiving areas A, B, C, and D arranged in the clockwise direction. A detection signal having a magnitude proportional to the intensity is output to the amplifier circuit 44 as a light reception signal (a, b, c, d).

  The amplifying circuit 44 amplifies the received light signals (a, b, c, d) output from the photodetector 43 with the same amplification factor to generate received light signals (a ′, b ′, c ′, d ′). And output to the focus error signal generation circuit 45 and the SUM signal generation circuit 48. The amplification circuit 44 is set to an initial predetermined amplification factor that is not so large when the amplification factor is not instructed from the controller CT. However, when an instruction is input from the controller CT, the amplification factor is set according to the instruction. (Refer to the amplification factor that changes in a staircase pattern in FIG. 12B).

  In this embodiment, focus servo control based on the astigmatism method is used. The focus error signal generation circuit 45 generates a focus error signal by calculation using the amplified light reception signals (a ′, b ′, c ′, d ′). That is, the focus error signal generation circuit 45 performs a calculation of (a ′ + c ′) − (b ′ + d ′), and outputs the calculation result to the focus servo circuit 46 as a focus error signal. The focus error signal (a ′ + c ′) − (b ′ + d ′) represents the amount of deviation of the focal position of the laser beam from the surface of the imaging plate 28.

  The focus servo circuit 46 is controlled by the controller CT, generates a focus servo signal based on the focus error signal, and outputs the focus servo signal to the drive circuit 47. The drive circuit 47 drives the focus actuator 40 in accordance with the focus servo signal to displace the objective lens 39 in the optical axis direction of the laser light. In this case, by generating a focus servo signal so that the value of the focus error signal (a ′ + c ′) − (b ′ + d ′) is always a constant value (for example, zero), a laser is applied to the surface of the imaging plate 28. The light can be continuously collected.

  The SUM signal generation circuit 48 adds the received light signals (a ′, b ′, c ′, d ′) to generate a SUM signal (a ′ + b ′ + c ′ + d ′) and outputs it to the A / D conversion circuit 49. To do. The intensity of the SUM signal corresponds to the intensity of the laser light reflected by the imaging plate 28 and the intensity of the light generated by the stimulated light emission, but the intensity of the laser light reflected by the imaging plate 28 is substantially constant. Therefore, the intensity of the SUM signal corresponds to the intensity of light generated by the stimulated light emission. That is, the intensity of the SUM signal corresponds to the intensity of the diffracted X-ray incident on the imaging plate 28.

  The A / D conversion circuit 49 is controlled by the controller CT, receives the SUM signal from the SUM signal generation circuit 48, converts the instantaneous value of the input SUM signal into digital data, and outputs the digital data to the controller CT.

  Further, the laser detection device PUH includes a condenser lens 50 and a photodetector 51. The condensing lens 50 condenses the laser light that is a part of the laser light emitted from the laser light source 33 and reflected without passing through the polarization beam splitter 37 on the light receiving surface of the photodetector 51. The photodetector 51 is a light receiving element that outputs a light reception signal corresponding to the intensity of light collected on the light receiving surface. Therefore, the photodetector 51 outputs a light reception signal corresponding to the intensity of the laser light emitted from the laser light source 33 to the laser driving circuit 34.

  Further, an LED 52 is provided adjacent to the objective lens 39. The LED 52 is controlled by the LED driving circuit 53 to emit visible light and erase the diffraction ring imaged on the imaging plate 28. The LED drive circuit 53 is controlled by the controller CT, and supplies a drive signal for generating visible light having a predetermined intensity to the LED 52.

  The controller CT is an electronic control unit mainly including a microcomputer including a CPU, ROM, RAM, a large capacity storage device, etc., and the diffraction ring imaging program shown in FIG. 4 stored in the large capacity storage device, FIG. And the optimum setting program shown in FIG. 5B, the peak detection program shown in FIG. 6, the diffraction ring reading program shown in FIGS. 7A and 7B, and the diffraction ring elimination program shown in FIG. The controller CT has an input device 55 for an operator to input various parameters, work instructions, and the like, and a display device 54 for visually informing the operator of various setting conditions, operating conditions, measurement results, and the like. And are connected. The controller CT processes the digital data of the SUM signal output from the A / D conversion circuit 49 to detect the intensity of the light emitted from the phosphor of the imaging plate 28.

  Next, a procedure for measuring the shape of the diffraction ring by the diffraction X-ray of the measurement object OB and the intensity of the diffraction X-ray for each diffraction ring using the X-ray diffraction measurement apparatus configured as described above will be described. First, the operator attaches the measurement object OB to the elevating stage 12a of the elevator 12, raises the elevating stage 12a, and sets the measurement object OB in the frame FR. When the operator inputs the material of the measurement object OB (for example, iron in this embodiment) using the input device 55 and instructs the start of measurement, the controller CT executes the diffraction ring imaging program. To do. When a plurality of crystal structures (ferrite and austenite) are included like iron, whether or not to measure the ratio of the plurality of crystal structures is also input using the input device 55. In this embodiment, it is also input that the ratio is measured.

  As shown in FIG. 4, when the controller CT starts the diffraction ring imaging program in step S100, the controller CT rotates the imaging plate 28 at a low speed with respect to the spindle motor control circuit 25 in step S102, and the index from the encoder 24a. When the signal is input, the rotation of the imaging plate 28 is stopped. Thereby, at the start of measurement, the rotation angle of the imaging plate 28 is set to 0 °. In the subsequent processing in the diffraction ring imaging program, the imaging plate 28 is not rotated. Next, in step S104, the controller CT controls the feed motor control circuit 22 to operate the feed motor 18 and moves the imaging plate 28 to the diffraction ring imaging position in cooperation with the position detection circuit 21. Let

  Next, the controller CT starts the operation of the sensor signal extraction circuit 32 in step S106. Next, in step S108, the controller CT controls the X-ray control circuit 14 to start emitting X-rays. Thereby, X-rays are irradiated onto the measurement object OB, and the X-rays reflected on the surface of the measurement object OB are received by the light receiving sensor 31. Next, in step S110, the controller CT inputs a light reception position signal from the sensor signal extraction circuit 32, and calculates the distance L between the imaging plate 28 and the measurement object OB using the input light reception position signal. In step S112, the controller CT determines whether or not the calculated distance L is within a predetermined reference range. If the distance L is outside the reference range, it is determined as “No”, and in step S114, the X-ray control circuit 14 is controlled to stop the X-ray irradiation to the measurement object OB.

  In step S116, the controller CT displays on the display device 54 that the position in the height direction of the measurement object OB is inappropriate, and information related to the height adjustment of the lifting stage 12a of the elevator 12. indicate. That is, it displays how much the lifting stage 12a should be raised or lowered. In step S126 described later, the diffraction ring imaging program is terminated. In this case, the operator instructs the start of measurement again using the input device 55 after adjusting the height of the lifting stage 12a. Since the time required from the above steps S108 to S114 is very short, the diffractive ring is not imaged on the imaging plate 28. Further, when the light receiving sensor 31 does not receive the X-ray reflected by the measurement object OB, only an indication that the position of the measurement object OB in the height direction is inappropriate is made in step S116. Thus, information relating to the height adjustment of the elevating stage 12a is not displayed. In this case, the position of the measurement object OB is considered to be in an extremely inappropriate position, and the height adjustment direction of the elevating stage 12a can be visually determined.

  On the other hand, if the distance L is within the predetermined reference range during the determination process in step S112, the controller CT determines “Yes” in step S112, proceeds to step S118, and outputs a sensor signal extraction circuit. The operation of 32 is stopped. Then, the controller CT starts measuring time in step S120, and determines whether or not a predetermined set time has elapsed in step S122. If the predetermined set time has not elapsed since the start of time measurement, it is determined as “No” in step S122 and the determination process is continued. That is, the controller CT stands by until a predetermined set time elapses from the start of time measurement. When a predetermined set time has elapsed from the start of time measurement, the controller CT determines “Yes” in step S122, and controls the X-ray control circuit 14 in step S124 to control the X-ray emitted by the X-ray emitter 13. The irradiation of the line is stopped, and the execution of the diffraction ring imaging program is terminated in step S126.

  As a result, the diffraction ring is imaged on the imaging plate 28. FIG. 9 shows a diffraction ring imaged on the imaging plate 28. When the measurement substance is iron as in this embodiment, a diffraction ring made of ferrite is formed on the inside, and a diffraction ring made of austenite on the outside. Is formed. The intensity of diffraction X-rays by ferrite is larger than the intensity of diffraction X-rays by austenite, and the diffraction ring by ferrite is imaged on the imaging plate 28 wider and more markedly than the diffraction ring by austenite. In other words, the intensity of stimulated emission by laser light irradiation, which will be described later, is greater in the case of a diffraction ring made of ferrite than in the case of a diffraction ring made of austenite.

  Next, the controller CT executes the optimum setting program shown in FIGS. 5A and 5B and the peak detection program shown in FIG. 6 in parallel with this program. The optimum setting program uses the SUM signal indicating the intensity of the stimulated light emission from the diffraction ring by the ferrite due to the laser light irradiation, the optimum value of the laser light intensity of the laser light source 33 by the laser driving circuit 34, and the amplification circuit 44. Is a program for obtaining the optimum value of the amplification factor of the SUM signal. The reason for obtaining this optimum value is that the intensity of the photostimulated luminescence from the austenite diffraction ring due to laser light irradiation is small because the austenite diffraction ring is not formed significantly as compared with the ferrite diffraction ring as described above. Even if it is small, it is performed in order to accurately measure the intensity of stimulated emission from the diffraction ring of austenite. The peak detection program is a program for detecting the peak position in the radial direction of the diffraction ring of the SUM signal.

  The execution of the optimum setting program is started in step S200 of FIG. 5A, and the controller CT outputs a plurality of switching pulse levels H (1) to H (NL) to the laser driving circuit 34 in step S202 to drive the laser. The data is stored in the circuit 34. The plurality of switching pulse levels H (1) to H (NL) respectively correspond to the measurement positions in the circumferential direction for each predetermined angle θL. The value NL represents the number of measured values per round. When the angle is expressed in radians, the predetermined angle θL and the value NL have a relationship of θL · NL = 2π. As the plurality of switching pulse levels H (1) to H (NL), values stored in advance in the controller CT may be used, or an operator may input using the input device 55. Note that the predetermined angle θL is relatively large and the value NL is not so large as compared with the case of actual diffraction ring measurement described later.

  Next, the controller CT calculates the diffraction ring reference radius R in step S204. The diffraction ring reference radius R is the radius of the diffraction ring when the residual stress of the measurement object OB is “0”. The diffraction ring reference radius R depends on the material of the measurement object OB and the distance L from the imaging plate 28 to the measurement object OB. That is, since the residual stress is “0”, the diffraction angle θa is determined by the material. Since the distance L and the diffraction ring reference radius R are in a proportional relationship, if the diffraction angle θa is stored in advance for each material, the diffraction ring reference radius R is calculated by the calculation of R = L · tan (θa). it can. When the diffraction angle θa of the measurement object OB is unknown, the powder of the measurement object OB is uniformly attached to the measurement object OB, and the diffraction ring imaging program is executed to execute the diffraction ring May be imaged. Then, the diffraction angle θa may be obtained using the above formula consisting of the radius R and the distance L of the diffraction ring at this time.

  In the case of this embodiment, iron containing two types of crystal structures of ferrite and austenite is used as the object to be measured OB. Input may be performed using the device 55. Therefore, the diffraction ring reference radii R1 and R2 of the two diffraction rings made of ferrite and austenite are calculated as the diffraction ring reference radius R. However, in the process of the optimum setting program, as described above, the optimum value of the intensity of the laser beam and the SUM signal are used by using the SUM signal indicating the intensity of the stimulated emission from the diffraction ring by the ferrite due to the laser beam irradiation. In this optimal setting program, only the diffraction reference radius R1 of the diffraction ring made of ferrite is used. Accordingly, in this step S204, only the diffraction ring reference radius R1 of ferrite is calculated, and the austenite diffraction ring reference radius R2 is not necessarily calculated.

  After step S204, the controller CT starts the operation of the position detection circuit 21 in step S206. In step S208, the feed motor control circuit 22 is instructed to move the imaging plate 28 to the reading start position in the diffraction ring reading region. The feed motor control circuit 22 drives and controls the feed motor 18 in cooperation with the position detection circuit 21 to move the imaging plate 28 to the reading start position. In a state where the imaging plate 28 is at the reading start position, the center of the objective lens 39, that is, the irradiation position of the laser light is positioned at a position smaller than the calculated diffraction ring reference radius R1 of the ferrite by a predetermined distance α. The predetermined distance α is a distance that is slightly larger than the distance at which the radius of the diffraction ring formed by the imaged ferrite may deviate from the diffraction ring reference radius R1. Thereby, the measurement of the diffraction ring by the ferrite is sufficiently started from the inside by the processing described later, and the diffraction ring by the ferrite is reliably detected.

  Here, the position signal from the position detection circuit 21 indicating the movement distance x from the movement limit position of the moving stage 15 to the lower right direction in FIGS. The relationship with the distance (ie, the radius value r of the irradiation position of the laser beam) will be described. In a state where the moving stage 15, that is, the imaging plate 28 is at the movement limit position, as shown in FIG. 10A, the distance from the center of the imaging plate 28 to the center position of the objective lens 39 is assumed to be Ro. In this case, the objective lens 39 is in the upper left direction in FIGS. 1 to 3 from the center position of the imaging plate 28, and the distance Ro is measured in advance and stored in the controller CT. On the other hand, as shown in FIG. 10B, when the imaging plate 28 is moved from the movement limit position by the distance x in the lower right direction in FIGS. It is represented by In this case, since the distance x is indicated by the position signal output from the position detection circuit 21 as described above, the radius value r of the irradiation position of the laser beam is output from the position detection circuit 21 in future processing. The value Ro stored in advance is added to the distance x represented by the position signal.

  As described above, when the imaging plate 28 is moved to the reading start position, as shown in FIG. 10C, the irradiation position of the laser beam is on the inner side by a predetermined distance α from the diffraction ring reference radius R1. In this case, the radius value r should be equal to the distance R1-α. Therefore, the distance x for moving the imaging plate 28 from the drive limit position in the lower right direction in FIGS. 1 to 3 is equal to x = R1−α−Ro. That is, in the process of moving to the reading start position in step S208, the table 27 is moved by the distance x (= R1-α-Ro) represented by the position signal output from the position detection circuit 21 as shown in FIGS. Move to the lower right.

  Next, in step S210, the controller CT instructs the spindle motor control circuit 25 to rotate the imaging plate 28 at a predetermined constant rotational speed. The spindle motor control circuit 25 controls the rotation of the spindle motor 24 so that the imaging plate 28 rotates at the specified constant rotation speed while calculating the rotation speed using the pulse signal from the encoder 24a. Accordingly, the imaging plate 28 starts to rotate at the predetermined constant rotational speed. Next, in step S212, the controller CT controls the laser driving circuit 34 to start irradiation of the imaging plate 28 with laser light from the laser light source 33. In this case, the controller CT causes the laser drive circuit 34 to drive the laser light source 33 with a low-level DC drive signal so that the intensity of the laser light becomes the low level LV1 shown in FIG. 34 is controlled. Therefore, in this state, the imaging plate 28 is irradiated with laser light with the intensity of the low level LV1.

  Next, in step S214, the controller CT instructs the focus servo circuit 46 to start focus servo control. Accordingly, the focus servo circuit 46 starts focus servo control by driving and controlling the focus actuator 40 via the drive circuit 47 using the focus error signal from the amplifier circuit 44 and the focus error signal generation circuit 45. . As a result, the objective lens 39 is driven and controlled in the optical axis direction so that the laser beam is focused on the surface of the imaging plate 28. After the processing in step S216, the controller CT starts the operations of the rotation angle detection circuit 26 and the A / D conversion circuit 49 in step S216. As a result, the rotation angle detection circuit 26 starts outputting the rotation angle θp from the reference position of the spindle motor 24 (imaging plate 28) to the controller CT, and the A / D conversion circuit 49 outputs the digital data of the instantaneous value of the SUM signal. Starts to be output to the controller CT.

  Next, in step S218, the controller CT instructs the feed motor control circuit 22 to start and move the imaging plate 28. The feed motor control circuit 22 drives and controls the feed motor 18 to move the imaging plate 28 from the reading start position to the bearing unit 19 side (lower right direction in FIGS. 1 and 2) at a constant speed. As a result, the irradiation position of the laser beam starts to move relative to the imaging plate 28 at a constant speed from the inner side to the outer side by a predetermined distance α from the diffraction ring reference radius R1 of the ferrite. In this state, the irradiation position of the laser beam is relatively spirally rotated on the imaging plate 28 by the processing in steps S210 and S212.

  After the processing in step S218, the controller CT initially sets the values of the circumferential direction number n and the radial direction number m to “1” in step S220. The imaging plate 28 is irradiated with high-level laser light intermittently while rotating the imaging plate 28 and moving the imaging plate 28 in the radial direction by a process described later. The laser beam irradiation is performed at a predetermined angle θL obtained by dividing 2π described above by the value NL. Therefore, as shown in FIG. 11, the reading point that is the irradiation position of the high-level laser beam is a position separated by a predetermined angle θL on the spiral locus, and the circumferential variable n and the radial direction number m are set as follows. And is expressed as P (n, m). The circumferential direction number n changes from “1” to NL while each of the reading points P (n, m) makes one round. The radial direction number m increases by “1” each time the reading point P (n, m) makes one round. The reading point P (1,1) corresponds to a position smaller than the above-described ferrite diffraction reference radius R1 by a predetermined distance α.

  Next, in step S222, the controller CT determines whether or not the rotation angle detection circuit 26 has input an index signal from the encoder 24a. If the rotation angle detection circuit 26 has not input the index signal, the controller CT determines “No” in step S222, and continues to execute the determination process in step S222 repeatedly. When the rotation angle detection circuit 26 inputs the index signal, the controller CT determines “Yes” in step S222, and captures the current rotation angle θp of the imaging plate 28 from the rotation angle detection circuit 26 in step S224. . In step S226, the controller CT calculates the difference between the current rotation angle θp and a predetermined rotation angle θL (n) specified by the variable n (in this case, n = 1 so that θL (1)). It is determined whether or not the absolute value | θp−θL (n) | is less than a predetermined allowable value. In this case, the predetermined rotation angles θL (1) to θL (NL) are stored in the controller CT in advance, and are the angles for the predetermined angle θL described above. If the absolute value | θp−θL (n) | is not less than the predetermined allowable value, the controller CT determines “No” in step S226 and repeatedly executes the processes in steps S224 and S226. That is, the controller CT stands by until the current rotation angle θp substantially matches the predetermined rotation angle θL (n). When the current rotation angle θp substantially coincides with the predetermined rotation angle θL (n), the controller CT determines “Yes” in step S226, that is, the absolute value | θp−θL (n) | is less than the predetermined allowable value. And the process proceeds to step S228.

In step S228, the controller CT instructs the laser drive circuit 34 to output the switching pulse level H (n) specified by the variable n (in this case, n = 1 so that H (1)). . In response to this instruction, the laser drive circuit 34 drives and controls the laser light source 33 with a pulse signal in which the pulse of the switching pulse level H (n) is superimposed on the low-level DC drive signal in step S212. In this case, the pulse signal has a predetermined width. Thereby, a pulsed laser beam having an intensity corresponding to the switching pulse level H (n) is output from the laser light source 33 to the reading point P (n, m) of the imaging plate 28.
(In this case, since n = 1 and m = 1, irradiation is performed at a position specified by P (1, 1)). Next, in step S230, the controller CT acquires the SUM signal from the A / D conversion circuit 49 during the irradiation of the pulsed laser beam, and the signal intensity S (n of the reading point P (n, m). , M) are stored in the memory. In step S230, the position signal from the position detection circuit 21 is acquired, and the radius value r is calculated by adding the predetermined distance Ro to the distance x represented by the position signal, and the reading point P (n, The radius value r (n, m) of m) is stored in the memory in correspondence with the signal intensity S (n, m). Thereby, the intensity of the photostimulated luminescence from the reading point P (n, m) of the imaging plate 28 by the pulsed laser beam having the intensity corresponding to the switching pulse level H (n) from the laser light source 33, that is, the reading point P ( The signal intensity S (n, m) representing the intensity of the X-ray diffracted light with respect to n, m) is stored in the memory together with the radius value r (n, m) representing the radius value of the reading point P (n, m). .

  Next, in step S232, the controller CT determines whether or not the stored signal strength S (n, m) is equal to or greater than a predetermined reference value. If the signal intensity S (n, m) is greater than or equal to the predetermined reference value, the controller CT determines “Yes” in step S232 and proceeds to step S236. On the other hand, if the signal strength S (n, m) is smaller than the predetermined reference value, the controller CT determines “No” in step S232, and in step S234, the stored signal strength S (n, m). After deleting m) and the radius value r (n, m), the process proceeds to step S236. When the signal intensity S (n, m) and the radius value r (n, m) are erased, the signal intensity S (n, m) smaller than a predetermined reference value is the peak position of the diffraction X-ray intensity in the radial direction of the diffraction ring. This is because it is unnecessary for detection.

  In step S236, the controller CT adds “1” to the circumferential direction number n. In step S238, the controller CT determines whether the variable n is greater than a value NL representing the number of reading points P (n, m) per revolution, that is, whether the imaging plate 28 has made one rotation. . In this case, since n = 2 and the circumferential direction number n is equal to or less than the value NL, the controller CT determines “No” in step S238 and returns to step S224.

  Then, the processes in steps S224 to S238 described above are repeated until the circumferential direction number n becomes larger than the value NL. By repeating the steps S224 to S238, the signal intensity S (n, m) and the radius value r (n, m) respectively corresponding to the rotation angles θL (1) to θL (NL) are stored in the memory. In this case, the switching pulse level H (n) designated by the circumferential direction number n is sequentially increased by the processing of step S228, so that the rotation angles θL (1) to θL (NL) as shown in FIG. ) Is irradiated to a position designated by a reading point P (n, m) of the imaging plate 28 with a pulsed laser beam whose intensity at a high level increases as the value increases. However, also in this case, if the signal strength S (n, m) is smaller than a predetermined reference value by the processing of steps S232 and S234, the signal strength S (n, m) and the radius value r (n , M) is deleted.

  When the circumferential direction number n becomes larger than the value NL by the circulation processing in steps S222 to S238, the controller CT determines “Yes” in step S238, and in step S240, a peak detection program described later. The presence / absence of an end command is determined. If there is no termination command yet, the controller CT determines “No” in step S240, returns the circumferential direction number n to “1” in step S242, and adds “1” to the radial direction number m. (In this case, m = 2). Then, the controller CT executes the processes of steps S222 to S238 described above, and the signal intensity relating to the read point P (n, m) corresponding to the rotation angle θL (1) to θL (NL) of the next radial position. S (n, m) and radius value r (n, m) are stored in the memory. Until the end command is issued, the radial direction number m (= 1, 2, 3,...) That is sequentially increased by “1” and each radial direction number m by the processing in steps S222 to S242. Signal strength S (n, m) corresponding to the read point P (n, m) designated by the circumferential direction number n (= 1 to NL) corresponding to the rotation angles θL (1) to θL (NL) and The radius value r (n, m) is sequentially stored in the memory. Also in this case, if the signal strength S (n, m) is smaller than a predetermined reference value, the signal strength S (n, m) and the radius value r (n, m) stored in the memory are deleted.

  Then, when there is an end command instruction from the peak detection program, the controller CT determines “Yes” in step S240, and executes an optimum laser intensity setting process in step S244. Before describing the optimum laser intensity setting process, a peak detection program executed in parallel with the optimum setting program will be described.

  The execution of the peak detection program is started in step S300 of FIG. 6, and the controller CT initializes the variable t to “1” in step S302. The variable t is a variable for causing a substantial peak detection process including steps S304 to S318 described later to be performed twice in succession, and represents the number of peak detection processes. Next, the controller CT initially sets the circumferential direction number n to “1” in step S304. The circumferential direction number n indicates the circumferential position for each predetermined angle θL as in the optimum setting program, but is independent of the circumferential direction number n used in the optimum setting program.

  After the processing in step S304, the controller CT determines in step S306 whether a peak radius rp (t, n), which will be described in detail later, exists, that is, whether the peak radius rp (t, n) has been detected. To do. In this case, the peak radius rp (t, n) indicates whether the first peak detection or the second peak detection is represented by the variable t, and the rotation angle θL (n) of the detected peak radius is represented by the variable n. The If the peak radius rp (t, n) has been detected, the controller CT determines “Yes” in step S306, adds “1” to the circumferential direction number n in step S308, and then proceeds to step S310. Thus, it is determined whether or not the circumferential direction number n is larger than a predetermined number. The predetermined number in this case is a value NL representing the number of measurement positions in one round. If the circumferential direction number n is less than or equal to the predetermined number, the controller CT determines “No” in step S310 and returns to step S306. If the circumferential direction number n is larger than the predetermined number, the controller CT determines “Yes” in step S310, and returns to step S304 to return the circumferential direction number n to “1”.

  On the other hand, if the peak radius rp (t, n) has not been detected, the controller CT determines “No” in step S306, and the signal intensity stored by the process of step S230 of FIG. 5A in step S312. It is determined whether or not the number of S (n, m) is a predetermined number or more. If the number of signal intensities S (n, m) is not equal to or greater than the predetermined number, the controller CT determines “No” in step S312, and executes the processes of steps S308 and S310 described above to execute step S306 or step S306. Return to S304. This is because the determination processing in step S312 is useless even if the peak detection processing described later is executed when the number of signal strengths S (n, m) is small. Note that the signal strength S (n, m) erased by the process of step S234 in FIG. 5A is not counted as the stored signal strength S (n, m).

  On the other hand, when the number of the stored signal strengths S (n, m) is equal to or larger than the predetermined number, the controller CT determines “Yes” in step S312, and determines whether or not there is a peak in step S314. To do. That is, the presence / absence of a peak of the value of the SUM signal is determined using all the radius values r (n, m) and the signal strength S (n, m) at the circumferential position designated by the circumferential number n. Specifically, as shown in FIG. 13, all the radius values r (n, m) at the circumferential position designated by the circumferential number n are taken on the horizontal axis, and the radius value r (n, m) Correspondingly, in the light receiving curve with the signal intensity S (n, m) on the vertical axis, there is a peak in the signal intensity S (n, m), that is, the signal intensity S (n, m) decreases after increasing. It is good to judge whether you did it. If there is no peak, the controller CT determines “No” in step S314, executes the processes of steps S308 and S310 described above, and returns to step S306 or step S304.

  As described above, while the steps S304 to S314 are repeatedly executed, the radius value r (n, m) and the signal strength S (n, m) are further increased by the processing of the optimum setting program executed in parallel. It is taken in and stored in memory one after another. For this reason, the peak is detected in step S314, and when detected, the controller CT determines “Yes” in step S314, and in step S316, the peak radius value r (n, m) is stored in the memory as the peak radius rp (t, n). Next, in step S318, the controller CT determines whether or not the number of acquired peak radii rp (t, n) is greater than or equal to a predetermined number. The predetermined number in this case is also a value NL representing the number of measurement positions in one round. If the number of acquired peak radii rp (t, n) is smaller than the predetermined number, the controller CT determines “No” in step S318, executes the processes of steps S308 and S310 described above, and performs step S306. Alternatively, the process returns to step S304.

  By repeating steps S304 to S318 in this way, the number of acquired peak radii rp (t, n) increases and reaches a predetermined number, that is, at all reading points P (n, m) in the circumferential direction. When the peak radius rp (t, n) is acquired, the controller CT determines “Yes” in step S318, and determines in step S320 whether or not there is a main measurement and a ratio measurement. Here, this measurement means an actual measurement of the diffraction ring by ferrite and austenite, which will be described in detail later. The ratio measurement means the measurement of the ratio of the diffraction integral intensity of ferrite and the diffraction integral intensity of austenite, which will be described in detail later. In this case, since this peak detection program is executed in parallel with the optimum setting program and is not the actual measurement, the controller CT determines “No” in step S320 and detects the peak in step S324. An end command indicating the end of is output.

  After outputting this end command, the controller CT determines whether or not an instruction to stop laser irradiation is given in step S326. The determination process in step S326 is to determine whether laser irradiation stop is instructed within a predetermined short time after the end command, and when laser irradiation stop is not instructed within a short time. Is determined as “No”. In other words, the determination process in step S326 is not performed immediately after the end command in step S324, but waits for a predetermined short time and determines whether there is an instruction to stop laser irradiation within the short time. is there. This laser irradiation stop instruction is output in step S290 of FIG. 5B of the optimum setting program and step S458 of FIG. 7B of the diffraction ring reading program, which will be described in detail later. In this case, the laser irradiation stop is performed. This instruction is not output within a short time. Therefore, in this case, the controller CT determines “No” in step S326, adds “1” to the variable t in step S328, and returns to step S304. Therefore, in this peak detection program, the controller CT starts to execute the second peak detection process including steps S304 to S318.

  Returning to the description of the optimum setting program in FIG. 5A. When the termination command is output as described above, the controller CT determines “Yes” in step S240, and executes the optimum laser intensity setting process in step S244. In the optimum laser intensity setting process, the peak radius rp (t, n) (t = t) corresponding to the reading point P (n, m) for one round obtained by the process of step S316 in FIG. 6 of the peak detection program. 1, n = 1 to NL), and the signal strength S (n, m) and the radius value r (n, m) stored in the memory in pairs in step S230 of FIG. 5A of the optimum setting program are used. The First, a radius value r (n, m) equal to the peak radius rp (t, n) (t = 1, n = 1 to NL) is extracted, and the signal intensity corresponding to the radius value r (n, m) is extracted. S (n, m) is extracted. As a result, the signal intensity S (n, m) for one round in which the signal intensity in the radial direction is the peak for the diffraction ring made of ferrite is extracted. In this case, the circumferential direction number n changes between 1 and NL, and the intensity of the laser beam from the laser light source 33 is increased as the circumferential direction number n increases by “1” by the process of step S228. It changes as shown in A). Therefore, taking the intensity of the laser beam (n = 1 to NL) on the horizontal axis and taking the extracted signal intensity S (n, m) as a peak value, the change of the peak value with respect to the intensity of the laser beam is graphed. As shown in FIG.

  In order to set the optimum value of the intensity of the laser beam, as shown in FIG. 14A, the ratio ΔP of the change of the peak value with respect to the change of the intensity of the laser beam (that is, the intensity of the laser beam is changed with a constant change amount). The intensity of the laser beam before the change when the change amount ΔP of the peak value in the changing state is below the set value is set as the optimum value. Even if the intensity of the laser beam is increased, the rate of change ΔP of the peak value may not fall below the set value until the end as shown in FIG. 14B, but in this case, the intensity of the laser beam Is set to a value corresponding to the maximum peak value. Since these optimum values correspond to the switching pulse level H (n) designated by the circumferential direction number n, actually, the switching pulse level H (n) corresponding to the optimum value is set as the optimum laser intensity. . Then, the set optimum laser intensity is output to the laser drive circuit 34 and stored in the laser drive circuit 34, and the high-level laser beam in future processing (that is, setting of the optimum amplification factor and measurement processing of the diffraction ring). It is used as a set pulse level that is the intensity of.

  After the optimum laser intensity setting process in step S244, the controller CT clears all the stored signal intensity S (n, m) and radius value r (n, m) in step S246 of FIG. 5B. Next, in step S248, the controller CT controls the feed motor control circuit 22 to stop the operation of the feed motor 18, thereby stopping the imaging plate 28. In step S250, the controller CT controls the focus servo circuit 46. The focus servo control is stopped by instructing the stop of the focus servo control. Then, the controller CT moves the imaging plate 28 to the reading start position by the processing of steps S252, S254, and S256 similar to steps S208, S214, and S210 of FIG. 5A described above, starts focus servo control, and performs imaging. The movement of the plate 28 is started. Thus, as in the case described above, the laser light is focused on the imaging plate 28 and the irradiation position of the laser light is rotated from the diffraction ring reference radius R1 of the ferrite while rotating on the imaging plate 28. It starts to move at a constant speed from the inside to the outside by the distance α. The operation of the position detection circuit 21, rotation of the imaging plate 28, laser light irradiation at the low level LV1, operation of the rotation angle detection circuit 26, and operation of the A / D conversion circuit 49 are continued as before. Has been.

  After the processing in step S256, the controller CT initializes the values of the circumferential direction number n and the radial direction number m to “1” in step S258, similarly to the processing in steps S220 and S222. The process proceeds to step S262 and subsequent steps on condition that the rotation angle detection circuit 26 has input the index signal from the encoder 24a.

  In step S262, the controller CT outputs an amplification factor g (n) specified by the circumferential direction number n to the amplifier circuit 44 (in this case, n = 1 so that g (1)) and amplifies it. The amplification factor of the circuit 44 is set to the amplification factor g (n). As shown in FIG. 12B, the amplification factor g (n) increases by a predetermined amount sequentially with respect to the increase in the circumferential direction number n from 1 to Ng, and is stored in the controller CT in advance. Yes. In addition, you may make it an operator input these amplification factors g (1) -g (Ng) using the input device 55. FIG. The plurality of amplification factors g (1) to g (Ng) respectively correspond to measurement positions in the circumferential direction for each predetermined angle θg. The value Ng represents the number of measured values per round. When the angle is expressed in radians, the predetermined angle θg and the value Ng have a relationship of θg · Ng = 2π. The predetermined angle θg and the value Ng may be the same as or different from the above-described predetermined angle θL and the value NL, but the predetermined angle θg is relatively smaller than the case of the actual diffraction ring measurement described later. The value Ng is not so large.

  Next, in step S264, the controller CT fetches the current rotation angle θp of the imaging plate 28 from the rotation angle detection circuit 26 in the same manner as in step S224 described above. In step S226, the controller CT calculates the difference between the current rotation angle θp and a predetermined rotation angle θg (n) specified by the variable n (in this case, n = 1 and θg (1)). It is determined whether or not the absolute value | θp−θg (n) | is less than a predetermined allowable value. In this case, the predetermined rotation angles θg (1) to θg (Ng) are stored in the controller CT in advance and are the angles for the predetermined angle θg described above. However, the predetermined rotation angles θg (1) to θg (Ng) are equal to the predetermined rotation angles θg (1) to θg, even if the predetermined angle θg and the value Ng are equal to the predetermined angles θL and NL, respectively. It is different from (Ng). This is because the position irradiated with the high-level pulsed laser light is different from the above case. If the absolute value | θp−θg (n) | is not less than the predetermined allowable value, the controller CT determines “No” in step S260 and repeatedly executes the processes in steps S264 and S266. That is, the controller CT stands by until the current rotation angle θp substantially matches the predetermined rotation angle θg (n). When the current rotation angle θp substantially coincides with the predetermined rotation angle θg (n), the controller CT determines “Yes”, that is, the absolute value | θp−θg (n) | is less than the predetermined allowable value in step S264. And the process proceeds to step S268.

  In step S268, the controller CT instructs the laser drive circuit 34 to output a pulse corresponding to the set pulse level stored in the laser drive circuit 34 set by the process in step S244. In response to this instruction, the laser drive circuit 34 drives and controls the laser light source 33 with a pulse signal in which a pulse having a predetermined width having the set pulse level is superimposed on the low-laser DC drive signal in step S212. As a result, a pulsed laser beam having an intensity corresponding to the set pulse level from the laser light source 33 is read at the reading point P (n, m) of the imaging plate 28 (in this case, since n = 1 and m = 1, P ( 1, 1)). Next, in step S270, the controller CT acquires the SUM signal from the A / D conversion circuit 49 and the position detection circuit 21 during the irradiation of the pulsed laser light, as in step S230. The radius value r is calculated using the distance x represented by the acquired position signal, and is stored as the signal intensity S (n, m) and radius value r (n, m) of the reading point P (n, m). Remember each. Thereby, the intensity of the photostimulated light emission from the reading point P (n, m) of the imaging plate 28 by the pulsed laser beam having the intensity corresponding to the set pulse level from the laser light source 33, that is, the reading point P (n, m). The signal intensity S (n, m) representing the intensity of the diffracted X-ray with respect to the signal, and the signal intensity S (n, m) amplified by the amplification factor g (n) set by the amplifier circuit 44 is read point It is stored in the memory together with a radius value r (n, m) representing the radius value of P (n, m).

  Next, the controller CT performs a signal intensity S (n, m) and a signal intensity S (n, m) less than a predetermined reference value by the processes in steps S272 and S274 similar to the processes in steps S232 and S234 described above. The radius value r (n, m) corresponding to is deleted. In step S276, the controller CT adds “1” to the circumferential direction number n, and in step S278, the variable n is larger than the value Ng representing the number of read points P (n, m) per round. That is, it is determined whether or not the imaging plate 28 has rotated once. In this case, since n = 2 and the circumferential direction number n is equal to or less than the value Ng, the controller CT determines “No” in step S278 and returns to step S262. In step S262, the amplification factor of the amplification circuit 44 is set to the amplification factor g (n) specified by the circumferential direction number n (in this case, g (n) = 2), that is, the amplification factor g (n) that increases sequentially. Is done.

  Then, the processes in steps S262 to S278 described above are repeated until the circumferential direction number n becomes larger than the value Ng. By repeating these steps S262 to S278, the signal intensity S (n, m) and the radius value r (n, m) corresponding to the rotation angles θg (1) to θg (Ng) are stored in the memory. In this case, since the amplification factor g (n) of the amplifier circuit 44 specified by the variable n is sequentially increased by the processing of step S262, as shown in FIG. 12B, the rotation angles θg (1) to θg ( A signal strength S (n, m) that increases as Ng) increases is input to the controller CT. In this case, the intensity of the pulsed laser beam is always constant.

  When the circumferential direction number n becomes larger than the value Ng by the circulation process in steps S262 to S278, the controller CT determines “Yes” in step S278, and the process in step S280 similar to step S240 is performed. Thus, the presence / absence of an end command by the peak detection program is determined. If there is no end command yet, the controller CT determines “No” in step S280, and returns the circumferential direction number n to “1” and the radial direction number by the processing in step S282 similar to step S242. “1” is added to m (in this case, m = 2). Then, the controller CT executes the processes of steps S260 to S278 described above, and the signal intensity relating to the read point P (n, m) corresponding to the rotation angle θg (1) to θg (Ng) of the next radial position. S (n, m) and radius value r (n, m) are stored in the memory. Until the end command is issued, the radial direction number m (= 1, 2, 3,...), Which is sequentially increased by “1”, and each radial direction number m by the processing in steps S260 to S282. Signal intensity S (n, m) corresponding to the read point P (n, m) designated by the circumferential direction number n (= 1 to Ng) corresponding to the rotation angles θg (1) to θg (Ng) The radius value r (n, m) is sequentially stored in the memory. Also in this case, if the signal intensity S (n, m) is smaller than a predetermined reference value, the signal intensity S (n, m) and the radius value r (n, m) stored in the memory are deleted. .

  Then, when there is an end command instruction from the peak detection program, the controller CT determines “Yes” in step S280, and executes an optimum amplification factor setting process in step S284. Before describing the optimum laser intensity setting process, the peak detection program executed in parallel will be described again.

  As described above, in the peak detection program, the controller CT executes the second peak detection process including steps S304 to S318 described above in a state where the variable t is set to “2” by the process of step S328. Yes. In this case, since the number of reading points P (n, m) per round is equal to the value Ng, the predetermined number in steps S310 and S318 is the value Ng. When the number of acquired peak radii rp (t, n) increases and reaches a predetermined number, that is, the value Ng by the repetition processing of steps S304 to S318, the controller CT determines “Yes” in step S318, As in the case described above, it is determined in step S320 whether or not there is a main measurement and a ratio measurement. Also in this case, since this is not the main measurement, the controller CT determines “No” in step S320, and outputs an end command indicating the end of peak detection in step S324. After the output of this end command, the controller CT determines whether or not the laser irradiation stop is instructed in step S326, as in the above case. In this case, the controller CT performs processing in step S290 in FIG. Since an instruction to stop laser irradiation is output within the predetermined short time, at that time, the controller CT determines “Yes” in step S326 and ends the execution of the peak detection program in step S330. .

  Here, the description returns to the description of the optimum setting program in FIG. 5B. When the termination command is output as described above, the controller CT determines “Yes” in step S280, and executes the optimum amplification factor setting process in step S284. Also in this optimum amplification factor setting process, the peak radius rp (t, n) (t = t) corresponding to the reading point P (n, m) for one round obtained by the process of step S316 of FIG. 6 of the peak detection program. 1, n = 1 to Ng), and the signal intensity S (n, m) and the radius value r (n, m) stored in the memory in pairs in step S270 of FIG. 5B of the optimum setting program are used. The Also in this case, as in the optimum laser intensity setting process, first, radius values r (n, m) respectively equal to the peak radius rp (t, n) (t = 2, n = 1 to Ng) are extracted, A signal intensity S (n, m) corresponding to the radius value r (n, m) is extracted. Also in this case, the circumferential direction number n changes between 1 and Ng, and the amplification factor g (n) of the amplifier circuit 44 is increased every time the circumferential direction number n increases by “1” by the process of step S262. It changes as shown in FIG. Therefore, taking the intensity of the laser beam (n = 1 to Ng) on the horizontal axis and taking the extracted signal intensity S (n, m) as the peak value, the change of the peak value with respect to the intensity of the laser beam is graphed. As shown in FIG.

Also in this case, as shown in FIG. 14A, in order to set the amplification factor of the amplification circuit 44 to an optimum value, the ratio ΔP of the change in peak value to the change in amplification factor (that is, the amplification factor is constant). The amplification factor before the change when the change amount ΔP) of the peak value in the state of being changed by the change amount is less than the set value is set as the optimum value. Also in this case, as shown in FIG. 14B, if the peak value change ratio ΔP does not fall below the set value until the end, the optimum value of the amplification factor is set to a value corresponding to the maximum value of the peak value. Set. Since these optimum values correspond to the amplification factor g (n) specified by the circumferential direction number n, actually, the amplification factor g corresponding to the optimum value.
(n) is set as the optimum amplification factor. Then, the set optimum amplification factor is output to the amplification circuit 44 and stored in the amplification circuit 44, and the amplification factor of the amplification circuit 44 in the future processing (ie, diffraction ring measurement processing), that is, the light reception from the photodetector 43. Used as a signal amplification factor.

  After the optimum gain setting process in step S284, the controller CT instructs the focus servo circuit 46 to stop the focus servo control in step S286 in FIG. 5B, thereby stopping the focus servo control. Next, in step S288, the controller CT controls the laser drive circuit 34 to stop the laser light irradiation by the laser light source 33. Furthermore, the controller CT stops the operation of the A / D conversion circuit 49 and the rotation angle detection circuit 26 in step S290, and controls the feed motor control circuit 22 to stop the operation of the feed motor 18 in step S292. As a result, the imaging plate 28 is stopped, and the execution of the optimum setting program is terminated in step S294. Note that the operation of the position detection circuit 21 and the rotation of the imaging plate 28 are continued as before.

  When the execution of the optimum setting program is completed, the controller CT starts executing the diffraction ring reading program of FIGS. 7A and 7B. In this case, the peak detection program of FIG. 6 is also executed in parallel with the execution of the diffraction ring reading program. The execution of the diffraction ring reading program is started in step S400 of FIG. 7A, and the controller CT calculates the diffraction ring reference radius R in step S402. The calculation of the diffraction ring reference radius R is substantially the same as the processing in step S204 in FIG. 5A of the optimum setting program described above. The distance L from the imaging plate 28 to the measurement object OB and the diffraction angle related to the measurement object OB. Using θa, the diffraction ring reference radius R is calculated by the calculation of R = L · tan (θa). In this embodiment, iron is the object to be measured OB, and in this case, diffraction rings with two types of crystal structures of ferrite and austenite are measured, so the diffraction ring reference radii R1 and R2 for ferrite and austenite are calculated. And used for subsequent processing. If two types of diffraction ring reference radii R1 and R2 of ferrite and austenite are calculated and stored by the process of step S204 in FIG. 5A, the diffraction ring reference radii R1 and R2 are calculated in step S402. It is also possible to use the two types of calculated diffraction ring reference radii R1 and R2 stored in the future processing without calculation. When only the ferrite diffraction ring reference radius R1 is calculated and stored by the process of step S204 in FIG. 5A, the austenite diffraction ring reference is not calculated without calculating the ferrite diffraction ring reference radius R1. Only the radius R2 may be calculated.

  After the processing in step S402, the controller CT moves the imaging plate 28 to the reading start position and starts laser light irradiation by the processing in steps S404 and S406 similar to steps S208 and S212 in FIG. 5A described above. . Also in this case, the reading start position is an inner position by a predetermined distance α from the diffraction ring reference radius R1 of the ferrite. Next, the controller CT starts focus servo control by the processing of steps S408 and S410 similar to steps S214 and S216 of FIG. 5A described above, and operates the rotation angle detection circuit 26 and the A / D conversion circuit 49. Start operation. Then, the controller CT starts moving the imaging plate 28 at a constant speed in the lower right direction of FIGS. 1 and 2 by the process of step S412 similar to the process of step S218 of FIG. 5A described above. Thus, as in the case described above, the laser light is focused on the imaging plate 28 and the irradiation position of the laser light is rotated from the diffraction ring reference radius R1 of the ferrite while rotating on the imaging plate 28. It starts to move at a constant speed from the inside to the outside by the distance α. However, in this state, the laser beam irradiation level is the low level LV1 (see FIG. 12A).

  After the processing in step S412, the controller CT initializes the values of the circumferential direction number n and the radial direction number m to “1” in step S414, similarly to the processing in steps S220 and S222, and in step S416. The process proceeds to step S418 and subsequent steps on condition that the rotation angle detection circuit 26 has input the index signal from the encoder 24a.

  In step S418, the controller CT takes in the current rotation angle θp of the imaging plate 28 from the rotation angle detection circuit 26 as in the case of step S224 described above. In step S226, the controller CT determines that the absolute value | θp−θ (n) | of the difference between the current rotation angle θp and the predetermined rotation angle θ (n) specified by the variable n is a predetermined allowable value. It is determined whether it is less than. In this case, the rotation angle θ (n) designated by the circumferential direction number n is an angle that increases by a predetermined angle θ as the circumferential direction number n increases by “1” from 1 to N. The angles θ (1) to θ (N) are stored in advance in the controller CT. The value N represents the number of measured values per round. When the angle is expressed in radians, the predetermined angle θ and the value N have a relationship of θ · N = 2π. The predetermined angle θ is smaller than the aforementioned predetermined angles θL and θg, and the value N is larger than the aforementioned NL and Ng. This is because in the actual measurement of the diffraction ring, the number of measurement points is increased as compared with the case of setting the optimum laser beam intensity and amplification factor.

  If the absolute value | θp−θ (n) | is not less than the predetermined allowable value, the controller CT determines “No” in step S420 and repeatedly executes the processes in steps S418 and S420. That is, the controller CT stands by until the current rotation angle θp substantially matches the predetermined rotation angle θ (n). When the current rotation angle θp substantially matches the predetermined rotation angle θ (n), the controller CT determines that “Yes”, that is, the absolute value | θp−θ (n) | And the process proceeds to step S422.

  In step S422, the controller CT corresponds to the set pulse level stored in the laser drive circuit 34 by the process of step S244 with respect to the laser drive circuit 34, similarly to the process of step S268 of FIG. 5B described above. Instructs pulse output. In response to this instruction, the laser drive circuit 34 drives and controls the laser light source 33 with a pulse signal in which a pulse having a predetermined width having the set pulse level is superimposed on the low-laser DC drive signal in step S212. Thereby, a pulsed laser beam having an intensity corresponding to the set pulse level is emitted from the laser light source 33 to a position specified by the reading point P (n, m) of the imaging plate 28. Next, in step S424, the controller CT acquires the SUM signal from the A / D conversion circuit 49 and the position detection circuit 21 during the irradiation of the pulsed laser light, as in step S230. Taking the position signal, the radius value r is calculated using the distance x represented by the position signal, and the signal intensity S (n, m) and radius value r (n, m) at the reading point P (n, m). Respectively stored in the memory. In this case, the light reception signal supplied from the photodetector 43 used for generating the SUM signal to the amplification circuit 44 is amplified by the amplification factor stored in the amplification circuit 44 by the optimum amplification factor setting process in step S284 of FIG. 5B. Has been.

  Thereby, the intensity of the photostimulated light emission from the reading point P (n, m) of the imaging plate 28 by the pulsed laser beam having the intensity corresponding to the set pulse level from the laser light source 33, that is, the reading point P (n, m). The signal intensity S (n, m) representing the intensity of the diffracted X-ray with respect to the signal intensity S (n, m) amplified by the amplification circuit 44 with the optimum amplification factor is read point P (n, m). ) Is stored in the memory together with a radius value r (n, m) representing the radius value.

  Next, the controller CT performs a signal intensity S (n, m) and a signal intensity S (n, m) less than a predetermined reference value by the processes in steps S426 and S428 similar to the processes in steps S232 and S234 described above. The radius value r (n, m) corresponding to is deleted. In step S430, the controller CT adds “1” to the circumferential direction number n, and in step S432, the variable n is greater than the value N representing the number of read points P (n, m) per round. That is, it is determined whether or not the imaging plate 28 has rotated once. In this case, since the circumferential direction number n is “1” and is equal to or less than the value N, the controller CT determines “No” in step S432 and returns to step S418. Then, the processes in steps S418 to S432 described above are repeated until the circumferential direction number n becomes larger than the value N. By repeating the steps S418 to S432, the signal intensity S (n, m) and the radius value r (n, m) corresponding to the rotation angles θ (1) to θ (N) are stored in the memory.

  When the circumferential direction number n becomes larger than the value N by the circulation process of steps S418 to S432, the controller CT determines “Yes” in step S432, and the process of step S434 similar to step S240 described above. Thus, the presence / absence of an end command by the peak detection program is determined. When there is no end command yet, the controller CT determines “No” in step S434, and returns the circumferential direction number n to “1” and the radial direction number by the processing of step S436 similar to step S242. “1” is added to m. Then, the controller CT executes the processes of steps S416 to S432 described above, and the signal intensity relating to the read point P (n, m) corresponding to the rotation angle θ (1) to θ (N) of the next radial position. S (n, m) and radius value r (n, m) are stored in the memory. By the processes in steps S416 to S436 until such an end command is issued, the radial direction number m (= 1, 2, 3,...) That is sequentially increased by “1” and the rotation is performed for each radial direction number m. The signal intensity S (n, m) and the radius value r () regarding the reading point P (n, m) designated by the circumferential direction number n (= 1 to N) corresponding to the angles θ (1) to θ (N). n, m) are sequentially stored in the memory. Also in this case, if the signal strength S (n, m) is smaller than a predetermined reference value, the signal strength S (n, m) and the radius value r (n, m) stored in the memory are deleted.

  If there is an instruction to end the peak detection program, the controller CT determines “Yes” in step S434, and proceeds to step S438 in FIG. 7B. Before describing the processing after step S438, the peak detection program executed in parallel will be described.

  In this case as well, the peak detection program is started in step S300 of FIG. 6, and after setting the variable t to “1” in step S302, the controller CT consists of steps S304 to S318 in the same manner as described above. The peak detection process is being executed. In this case, since the number of reading points P (n, m) per round is equal to the value N, the predetermined number in steps S310 and S318 is the value N. When the number of acquired peak radii rp (t, n) is increased by the repetition processing of steps S304 to S318 and reaches a predetermined number, that is, the value N, the controller CT determines “Yes” in step S318, In step S320, it is determined whether or not there is a main measurement and a ratio measurement. In this case, since it is a measurement of the diffraction ring for iron and includes measurement of the ratio of ferrite to austenite, the controller CT determines “Yes” in step S320 and proceeds to step S322.

  In the present embodiment in which the diffraction ring of iron ferrite and austenite is measured, the peak radius rp (t, n) (t = 1) for one turn related to the diffraction ring of ferrite is obtained by the peak detection process including steps S304 to S318. , N = 1 to N). In this case, since the peak radius of the diffraction ring of ferrite is actually measured, in the processing of step S316, the actual peak exists between the two signal intensities S (n, m). For this, it is preferable to calculate the radius value by an interpolation operation to obtain the peak radius rp (t, n).

  In step S322, the controller CT inputs the position of the table 27 (that is, the imaging plate 28) from the position detection circuit 21, and determines whether the imaging plate 28 exceeds the reading end position using the input position. . The reading end position of the imaging plate 28 is a state in which the center position of the objective lens 39, that is, the irradiation position of the laser light is outside the predetermined distance α from the reference radius of the diffraction ring. Specifically, since the object to be measured in this case is a ferrite diffraction ring, the center position of the objective lens 39 is located outside the calculated ferrite diffraction ring reference radius R1 by a predetermined distance α. is there. If the imaging plate 28 does not exceed the reading end position, “No” is continuously determined in step S322, and the determination process in step S322 is repeatedly executed.

  In this state, an end command is not output by the process of the next step S324. Accordingly, the controller CT determines “No” in step S434 of FIG. 7A, returns the circumferential direction number n to “1” and increases the radial direction number m by “1” by the process of step S436, The signal intensity S (n, m) and the radius value r (n, m) are further accumulated and stored by the cyclic processing in steps S416 to S436. In this case as well, if the signal strength S (n, m) is smaller than the reference value by the processing in steps S426 and S428, the signal strength S (n, m) and the radius value r (n, m) are deleted. . The reason for accumulating and storing the signal intensity S (n, m) and the radius value r (n, m) after the peak radius rp (t, n) for one round is detected in this way is the diffraction ring (in this case) This is for obtaining the signal intensity S of the diffraction ring distributed in the radial direction as shown in FIG.

  When the imaging plate 28 exceeds the reading end position, the controller CT determines “Yes” in step S322 in FIG. 6, and outputs an end command indicating the end of peak detection in step S324. After the output of this end command, the controller CT determines whether or not the stop of laser irradiation has been instructed in step S326, as in the above case. In this case, up to the processing of step S454 in FIG. Since there is no instruction to stop laser irradiation, it is not performed within the predetermined short time. Therefore, in this case, the controller CT determines “No” in step S326, adds “1” to the variable t in step S328, and returns to step S304. Therefore, in this peak detection program, the controller CT starts to execute the second peak detection process including steps S304 to S318 and the measurement end determination process of steps S320 and S322.

  Based on the output of the end command, the controller CT determines “Yes” in step S434 in FIG. 7A, and proceeds to step S438 in FIG. 7B. In step S438, the controller CT determines all signal intensities S (n, m) and radius values r (n, m) accumulated and stored by the processing in step S424, and the signal intensity St ( n, m) and the radius value rt (n, m). In this case, in the stored signal intensity St (n, m) and the radius value rt (n, m), the variable n corresponds to the circumferential direction number n, and the variable m corresponds to the radial direction number m. The initial signal strength St (n, m) and radius value rt (n, m) (for example, S1 (n, m) and radius value r1 (n, m)) are data relating to the diffraction ring of ferrite.

  Next, the controller CT determines whether or not reading of all diffraction rings has been completed in step S440. In this case, since reading of one diffraction ring (ferrite diffraction ring) is completed and other diffraction rings (austenite diffraction ring) remain, the controller CT determines “No” in step S440. Then, the processing after step S442 is executed. In step S442, the controller CT clears all the stored signal strengths S (n, m) and radius values r (n, m).

  Next, the controller CT stops the movement of the imaging plate 28 and stops the focus servo control by the processes of steps S444 and S446 similar to the processes of steps S248 and S250 of FIG. 5B. In step S448, the controller CT moves the imaging plate 28 to the next reading start position. The next reading start position of the imaging plate 28 is a position where the center position of the objective lens 39 is located inside the next diffraction ring reference radius R2 (in this embodiment, the austenite diffraction reference radius R2) by a predetermined distance α. . After the process of step S448, the controller CT starts focus servo control by the process of step S450 similar to step S254.

  After the start of the focus servo control in step S450, the controller CT returns to step S412 in FIG. 7A and starts moving the imaging plate 28 in the lower right direction in FIGS. 1 and 2 at a constant speed as described above. As a result, in a state where the laser beam is focus servo controlled on the imaging plate 28, the irradiation position of the laser beam rotates on the imaging plate 28, and from the inner side to the outer side by a predetermined distance α from the austenite diffraction ring reference radius R2. Start moving at a constant speed in the direction. As in the case of the ferrite diffraction ring described above, after the initial setting of the circumferential direction number n and the radial direction number m to “1” in step S414, until the end command is output by execution of the peak detection program, By the circulation process in steps S416 to S436, the radial direction number m (= 1, 2, 3,...) That increases sequentially by “1” and the rotation angle θ (1) to θ (N) for each radial direction number m. The signal intensity S (n, m) and the radius value r (n, m) corresponding to the reading point P (n, m) specified by the circumferential direction number n (= 1 to N) corresponding to the are sequentially stored in the memory. Remembered. Also in this case, if the signal intensity S (n, m) is smaller than a predetermined reference value, the signal intensity S (n, m) and the radius value r (n, m) stored in the memory are deleted. .

  In this state, as described above, the controller CT performs the second peak detection process including steps S304 to S318 and the measurement end determination process of steps S320 and S322 in parallel with the diffraction ring reading program of FIGS. 7A and 7B. Running. Then, as described above, when there is an instruction to end the peak detection program, the controller CT determines “Yes” in step S434, and proceeds to step S438 in FIG. 7B as described above. In this case, the measurement end determination process in step S322 is a determination process related to the second diffraction ring (austenite diffraction ring in the present embodiment), and the reading end position is the laser irradiation position (that is, the measurement position). Is a position moved outward by a predetermined distance α from the austenite diffraction ring reference radius R2.

  When the irradiation position of the laser beam exceeds the reading end position, the controller CT determines “Yes” in step S322, and outputs an end command in step S324. After the output of this end command, the controller CT determines whether or not the laser irradiation stop is instructed in step S326 as in the above case. In this case, the laser is processed by the process in step S454 in FIG. Since an instruction to stop irradiation is output within the predetermined short time, at that time, “Yes” is determined in step S326, and execution of the peak detection program is ended in step S330.

  Returning to the description of the diffraction ring reading program in FIGS. 7A and 7B again, there is an instruction to end the peak detection program, the controller CT determines “Yes” in step S434, and the process returns to step S438. In step S438, all signal intensities S (n, m) and radius values r (n, m) accumulated and stored by the process in step S424 are measured. , M) and the radius value rt (n, m). In this case, the stored signal intensity St (n, m) and radius value rt (n, m) are the signal intensity S2 (n, m) and radius value r2 (n, m) related to the austenite diffraction ring. is there.

  Next, as described above, the controller CT determines whether or not reading of all the diffraction rings has been completed in step S440. In this case, since the measurement of the second diffractive ring is completed, that is, the measurement of the austenite diffractive ring in the present embodiment is completed, the controller CT determines “Yes” in step S440, and after step S452 Execute the process.

  That is, the controller CT stops the focus servo control, stops the laser light irradiation, the A / D conversion circuit 49, and the rotation by the processes in steps S452 to S458 similar to the processes in steps S286 to S292 in FIG. The operation of the angle detection circuit 26 is stopped and the imaging plate 28 is stopped, and the execution of the diffraction ring reading program is terminated in step S460. Note that the operation of the position detection circuit 21 and the rotation of the imaging plate 28 are continued as before.

  In the above description, since it is input to measure the ratio of a plurality of crystal structures (in this embodiment, ferrite and austenite), the peak radius for one round consisting of steps S306 to S318 of the peak detection program of FIG. Even after the detection of rp (t, n), based on the determination of “Yes” in step S320, it is determined in step S322 whether the irradiation position (measurement position) of the laser beam has exceeded the reading end position. I tried to do it. However, the measurement of the ratio of the plurality of crystal structures is unnecessary, and if the measurement of the ratio is not input, the controller CT determines “No” in step S320 even at the time of the main measurement, and 1 Immediately after detecting the peak radius rp (t, n) of the circumference, the process proceeds to step S324.

  When the execution of the diffraction ring reading program is completed, the controller CT executes the diffraction ring deletion program of FIG. 8 for deleting the diffraction ring imaged on the imaging plate 28. Execution of the diffraction ring erasure program is started in step S500, and the controller CT instructs the feed motor control circuit 22 to move the imaging plate 28 to the erasure start position in the diffraction ring erasure region in step S502. . The feed motor control circuit 22 drives and controls the feed motor 18 in cooperation with the position detection circuit 21 to move the imaging plate 28 to the erase start position. In a state where the imaging plate 28 is at the erasing start position, the center of the visible light output from the LED 52 is located at a position smaller than the calculated diffraction ring reference radius R1 of the ferrite by a predetermined distance γ. Specifically, this position is output from the position detection circuit 21 when the distance from the center of the imaging plate 28 to the center of the visible light of the LED is Ro ′ in a state where the imaging plate 28 is at the drive limit position. It is a position where the position becomes R1-γ-Ro ′. Note that the predetermined distance γ is slightly larger than the predetermined distance α, and is a position deviated with a margin from the radius of the diffraction ring imaged by the ferrite. Thereby, the diffraction ring imaged by the ferrite is surely erased by the process described later.

  Next, in step S504, the controller CT controls the LED drive circuit 53 to start irradiation of the visible light to the imaging plate 28 by the LED 52. Next, in step S506, the controller CT instructs the feed motor control circuit 22 to start and move the imaging plate 28. The feed motor control circuit 22 drives and controls the feed motor 18 to move the imaging plate 28 from the erasing start position to the bearing portion 19 side (lower right direction in FIGS. 1 and 2) at a constant speed. Thereby, visible light from the LED 52 starts moving at a constant speed from the inside to the outside by a predetermined distance γ (γ> α) from the diffraction ring reference radius R1 of the ferrite while rotating in the imaging plate 28.

  After the processing in step S506, the controller CT inputs a position signal indicating the position of the imaging plate 28 from the position detection circuit 21 in step S508. In step S510, the current position of the imaging plate 28 indicates the erasure end position. Determine if it has exceeded. This end position is a position that is larger than the diffraction ring reference radius R1 of the ferrite by a predetermined distance γ. Specifically, the position output from the position detection circuit 21 is a position where R1 + γ−Ro ′. Then, until the current position of the imaging plate 28 exceeds the erasing end position, the controller CT determines “No” in step S510, and repeatedly executes the processes of steps S508 and S510. As a result, visible light from the LED 52 is irradiated to the rotating imaging plate 28 from the diffraction ring reference radius R1 from the inner side by a predetermined distance γ to the outer side by a predetermined distance γ, and thus formed by diffraction X-rays from ferrite. The diffraction ring is gradually erased from the inside.

  When the current position of the imaging plate 28 exceeds the erasing end position, the controller CT determines “Yes” in step S510, and causes the feed motor control circuit 22 to stop moving the imaging plate 28 in step S512. In step S514, the LED driving circuit 53 is instructed to stop the irradiation of visible light by the LED 52. Accordingly, the feed motor control circuit 22 stops the movement of the imaging plate 28 by stopping the operation of the feed motor 18. The LED drive circuit 53 stops the irradiation of visible light from the LED 52. In this state, the diffraction ring imaged by the ferrite is completely erased.

  After the processing in step S514, the controller CT determines in step S516 whether or not there is a next erasing position, that is, a diffraction ring to be further erased. In this case, in the present embodiment, the imaging plate 28 has a diffraction ring made of ferrite and a diffraction ring made of austenite, so the controller CT determines “No” in step S516 and returns to step S502. And the diffraction ring imaged with the austenite is erase | eliminated by the process of step S502-S510 mentioned above. In this case, the erase start position in step S502 is an inner position by a predetermined distance γ from the austenite diffraction ring reference radius R2, and the erase end position in step S510 is an outer position by a predetermined distance γ from the austenite diffraction ring reference radius R2. It is. Specifically, the erase start position is a position where the position output from the position detection circuit 21 becomes R2-γ-Ro ', and the erase end position is the position output from the position detection circuit 21 as R2 + γ-Ro'. Is the position. Thereafter, the processing of steps S512 and S514 stops the movement of the imaging plate 28, and the irradiation of visible light by the LED 52 also stops.

  After the process of step S514, the controller CT again determines the presence of the next erase position in step S516. In this case, the diffraction ring formed by the diffracted X-rays by austenite is erased. In step S516, "No", that is, it is determined that there is no next erase position, and the process proceeds to step S518. In step S518, the controller CT stops the operation of the position detection circuit 21. Next, the controller CT instructs the spindle motor control circuit 25 to stop the rotation of the imaging plate 28 in step S520. In response to this instruction, the spindle motor control circuit 25 stops the operation of the spindle motor 24 and stops the rotation of the imaging plate 28. After the rotation of the imaging plate 28 is stopped, the controller CT ends the execution of the diffraction ring elimination program in step S522.

  When the execution of the diffraction ring erasing program is completed, the controller CT sets the peak radius rp (1, n) of the ferrite diffraction ring and the peak radius rp (2, n) of the austenite diffraction ring by executing a program (not shown). The residual stress is calculated and displayed on the display device 54 by the cos α method. In the calculation of the residual stress, only one of the peak radius rp (1, n) of the ferrite diffraction ring and the peak radius rp (2, n) of the austenite diffraction ring may be used. Further, the controller CT creates image data of ferrite and austenite diffraction rings using the peak radii rp (1, n) and rp (2, n), and the ferrite and austenite diffraction rings are displayed on the display device 54. indicate. Thereby, the residual stress of the measurement object OB (iron) can be recognized from the deviation from the perfect circle of the diffraction ring.

  Further, the controller CT calculates the minimum value (that is, the signal intensity at a portion where no diffraction ring is formed) from all the intensity signals S1 (n, m) related to ferrite to all the intensity signals S1 (n, m). The subtracted values are summed up, and the total value is divided by the maximum value N of the circumferential direction number n at the time of measurement, and the diffraction integrated intensity relating to the diffraction ring of ferrite (corresponding to the area of the hatched region near the radius R1 in FIG. Calculate Further, a value obtained by subtracting the minimum value (that is, the signal intensity at a portion where no diffraction ring is formed) among all intensity signals S2 (n, m) from all intensity signals S2 (n, m) related to austenite. Summing up and dividing the total value by the maximum value N of the circumferential direction number n at the time of measurement, the diffraction integrated intensity (corresponding to the area of the hatched region in the vicinity of the radius R2 in FIG. 15) for the austenite diffraction ring is calculated. And the ratio of the ferrite and austenite contained in iron is acquired by the ratio of the diffraction integral intensity of ferrite and the diffraction integral intensity of austenite. Also in this case, it is preferable that the signal intensity distribution of ferrite and austenite as shown in FIG. From these residual stresses and ratios, the characteristics of iron can be evaluated.

  In the X-ray diffraction measurement apparatus operating as described above, a diffraction ring that is an image of the diffraction X-rays recorded on the imaging plate 28 by executing the optimum setting program of FIGS. 5A and 5B and the peak detection program of FIG. Are detected, and the intensity of the laser beam and the amplification factor of the received light signal are set so that the magnitude of the received light signal is optimum. Therefore, according to the embodiment, even when the intensity of the diffracted X-ray is weak, the intensity of the laser beam and the amplification factor of the received light signal are set so that the peak value of the received light signal corresponding to the intensity of the diffracted X-ray is increased. Therefore, it is possible to accurately measure the diffraction ring by diffracted X-rays, and to accurately determine the shape of the diffraction ring, the diffraction integral intensity, and the like. In addition, since the change width of the intensity of the laser beam is smaller than the change width of the gain of the received light signal, the peak value can be set to a value in the vicinity of the largest value, and in the signal intensity curve in the radial direction of the diffraction ring. The noise component can be reduced. That is, contrary to the above embodiment, after changing the signal amplification factor to a value in the vicinity where the peak value is the largest and setting the amplification factor optimally, the peak value is Saturates and does not change. On the other hand, according to the above-described embodiment, if the optimum value of the intensity of the laser beam is determined first, this is not the case, and the optimum signal intensity is determined and the signal level is optimized (maximum). Can be set to As a result, the S / N ratio of the received light signal is also good.

  Further, in the optimum laser intensity setting process in step S244 and the optimum amplification factor setting process in step S284 of the optimum setting program of FIGS. 5A and 5B of the above embodiment, the signal intensity S (n, m) (peak value) changes. When the amount does not reach a predetermined value, set the intensity of the laser light before the change or the gain of the received light signal to avoid saturation of the peak value, and near the peak value The value can be As a result, according to the above-described embodiment, the noise component of the received light signal due to reflection by a portion other than the diffraction ring by the surrounding X-ray diffraction can be suppressed to be small, and the diffraction ring by X-ray diffraction can be measured more accurately. The shape of the ring, diffraction integrated intensity, etc. can be obtained with higher accuracy. In particular, in order to set both the intensity of the laser beam and the amplification factor of the received light signal, if one is set to a large value, the peak value is saturated due to the optimum value of the other, and the other cannot be changed. However, it is easy to avoid such a situation.

  Moreover, in the said embodiment, the said measuring object is iron, and the peak detected by the peak detection program of FIG. 6 is based on the diffraction ring of a ferrite. As a result, if the peak value is set to the maximum value in the ferrite diffraction ring, the peak value can be sufficiently increased even in the austenite diffraction ring, and the austenite diffraction ring shape and austenite diffraction integrated intensity Can be obtained with high accuracy.

  Furthermore, in carrying out the present invention, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the object of the present invention.

  In the above embodiment, when setting the optimum laser intensity and signal amplification factor, the imaging plate 28 is rotated and moved so that the laser intensity and signal amplification factor are the same at the same rotational position. Changed. However, any method may be used as long as the peak value of the signal intensity of the sum signal SUM can be obtained with the same laser intensity and signal amplification factor. For example, first, the laser intensity or the signal amplification factor is set, the signal intensity of the thumb signal SUM is acquired while moving the imaging plate 28 in the radial direction without rotating, and the peak value in the radial direction is acquired. Next, the imaging plate 28 is rotated by a minute amount. Thereafter, the laser intensity or the signal amplification factor is set to the following value, and as described above, the signal intensity of the thumb signal SUM is acquired while moving the imaging plate 28 in the radial direction without rotating, and the radial direction is obtained. Get the peak value of. By repeating such an operation, the rotation angle at which the signal strength of the sum signal SUM is optimal in the same manner as in the above embodiment among the signal strengths of the sum signal SUM at the radial position where the signal strength of the sum signal SUM peaks. A laser intensity and a signal amplification factor corresponding to the above may be adopted.

  In the above embodiment, both the laser intensity and the signal amplification factor are set to be optimum. However, the measurement target is the same substance, and the optimum value of the laser intensity or the signal amplification factor is larger than that at the previous inspection. If it does not change, one may be fixed to the previous value as it is, and only the other of the laser intensity and the signal amplification factor may be changed and set to the optimum value.

  In the above embodiment, the optimum values of the laser intensity and the signal amplification factor are set to the values before the change when the change of the peak value with respect to the change of the laser intensity and the signal amplification factor does not reach the set value. However, instead of this, when the object to be measured is specified (iron is specified as in the present embodiment) and the peak value is almost known, only one of the laser intensity and the signal amplification factor is obtained. Alternatively, when both are changed and a predetermined value that is predetermined as a peak value is exceeded, the laser intensity and signal amplification factor at that time may be set to optimum values.

  In the above embodiment, when measuring the ratio of a specific structure, the imaging plate 28 is rotated to obtain a radial signal intensity curve at each rotational position of the diffraction ring, and the diffraction integration at each rotational position. The intensity is calculated and this value is averaged to obtain the diffraction integrated intensity. However, when only the ratio of a specific structure is measured, when high-speed measurement is more important than accuracy, the imaging plate 28 is not rotated. Alternatively, only the movement may be performed to obtain a curve of the signal intensity in the radial direction at a specific rotational position, and the diffraction integral intensity may be calculated.

  In the above embodiment, step S314 of the peak detection program of FIG. 6 executed in parallel with the optimum setting program of FIGS. 5A and 5B in order to set the optimum intensity of the laser beam and the amplification factor of the received light signal. By the processing of S316, the peak of the SUM signal value is detected using the radius value r (n, m) and the signal intensity S (n, m), and the peak radius value is set as the peak radius rp (t, n). I remembered it. Then, by the optimum laser intensity setting process in step S244 in FIG. 5A and the optimum amplification factor setting process in step S284 in FIG. 5B, radius values r (n, m) respectively equal to the peak radius rp (t, n) are extracted. Then, the signal intensity S (n, m) for one round which is a peak representing the diffraction ring corresponding to the radius value r (n, m) is extracted, and the extracted signal intensity S (n, m) for one round is extracted. ) Was used to determine the optimum intensity of the laser beam and the amplification factor of the received light signal.

  However, in this case, if the signal intensity S (n, m) for one round corresponding to the position of the peak (diffraction ring) can be extracted, the peak radius value is unnecessary, so the peak radius rp ( It is not necessary to use t, n). Instead of adopting the peak radius rp (t, n), when detecting the peak of the SUM signal value, the signal intensity S (n, m) for one round corresponding to the detected peak is stored. Information on variables n and m that can specify the signal strength S (n, m) of the circumference may be stored. However, when the peak detection program of FIG. 6 is executed in parallel with the diffraction ring reading program of FIGS. 7A and 7B, the peak radius rp (t, n) is necessary, so step S314 of FIG. The process of S316 needs to operate as described in the above embodiment.

  Moreover, in the said embodiment, it determines whether the position of the height direction of the measuring object OB is in a predetermined range using the light receiving position of the reflected light received by the light receiving sensor 31, If it was not within the range, the operator adjusted the height of the elevating stage 12a. However, the height of the elevating stage 12a may be automatically adjusted so that the position in the height direction of the measurement object OB represented by the light receiving position of the light receiving sensor 31 is within a predetermined range. . According to this, as long as the position in the height direction of the measurement object OB set by the operator is within a range in which the light receiving sensor 31 can receive the reflected light, the operator adjusts the height of the elevating stage 12a. Since there is no need, work efficiency can be improved. For example, the light receiving sensor 31 is not required if the distance between the imaging plate and the measurement object is always constant as in the conventional X-ray detection apparatus.

  In the above embodiment, the diffraction ring reference radius R is calculated using the light receiving position of the light receiving sensor 31, and an area in which the radius of the imaged diffraction ring may deviate from the diffraction ring reference radius R is assumed. The reading start position is determined. However, the laser beam may always be irradiated to a certain region without calculating the diffraction ring reference radius R. For example, the entire region of the imaging plate 28 may be irradiated with laser light. Similarly, visible light emitted from the LED 53 may be always irradiated with visible light emitted from the LED 53 in a certain region. For example, the entire area of the imaging plate 28 may be irradiated with visible light from the LED 53. However, in this case, the measurement time is longer than in the above embodiment.

  In the above embodiment, the laser detection device PUH is controlled by the focus servo. However, when the imaging plate 28 is rotated, the variation in the distance between the light receiving surface of the imaging plate 28 and the objective lens 39 is very small. If so, focus servo control is unnecessary.

DESCRIPTION OF SYMBOLS 13 ... X-ray emitter, 15 ... Moving stage, 18 ... Feed motor, 21 ... Position detection circuit, 24 ... Spindle motor, 26 ... Rotation angle detection circuit, 27 ... Table, 28 ... Imaging plate, 31 ... Light receiving sensor, 33 DESCRIPTION OF SYMBOLS ... Laser light source 34 ... Laser drive circuit 39 ... Objective lens 43 ... Photo detector 44 ... Amplifier circuit 48 ... SUM signal generation circuit 49 ... Conversion circuit 52 ... LED 54 ... Display device 55 ... Input device CT ... Controller

Claims (6)

An X-ray emitter that emits X-rays toward the measurement object;
A table in which a through hole for allowing the X-rays to pass through is formed in the center;
A diffracted light receiver that is fixed to the table and has a light receiving surface that receives the diffracted light of the X-ray diffracted by the measurement object, and that records a diffraction ring that is an image of the diffracted light;
A laser light source that emits laser light and a photodetector that receives the laser light, and irradiates the light receiving surface of the diffracted light receiver with the laser light, and is emitted from the diffracted light receiver by the irradiation of the laser light. A laser detector that receives light and outputs a received light signal corresponding to the received light intensity;
Rotating means for rotating the table around the central axis of the through hole;
A rotation angle detection circuit for detecting a rotation angle from a reference position in rotation of the table by the rotation means;
Moving means for moving the table relative to the laser detection device in a direction parallel to a light receiving surface of the diffracted light receiver;
A position detection circuit for detecting a moving position of the table by the moving means;
A laser drive circuit capable of driving and controlling the laser light source and changing the intensity of the laser light emitted from the laser light source;
An amplification circuit that amplifies and outputs a light reception signal from the photodetector;
In the X-ray diffraction measurement apparatus that irradiates the measurement object from the X-ray emitter and measures the diffraction ring recorded in the diffracted light receiver by the X-ray diffracted by the measurement object,
The rotation means and the moving means are controlled to rotate and move the diffracted light receiver in which the diffractive ring is recorded, so that the irradiation position of the laser light emitted from the laser detection device in the diffracted light receiver is determined. An irradiation position control means for rotating around the center of the diffracted light receiver and changing a radial distance from the center;
The rotation angle is detected while the irradiation position control means rotates the irradiation position of the laser beam in the diffracted light receiver around the center of the diffracted light receiver and changes the radial distance from the center. When the rotation angle of the table detected by the circuit is the same rotation angle, the intensity of the laser beam is made the same, and each time the rotation angle of the table changes by a predetermined angle from the same rotation angle, the laser beam Laser intensity control means for controlling the laser drive circuit so that the intensity of
A plurality of light reception signals from the amplifier circuit in respective states in which the rotation angle of the table is changed by the predetermined angle, each corresponding to a plurality of irradiation positions of laser light distributed in the radial direction of the diffracted light receiver Received light signal acquisition means for respectively acquiring the received light signal;
A plurality of light reception signals acquired by the light reception signal acquisition means, the rotation angles of the table being the same, and corresponding to a plurality of irradiation positions of laser light distributed in the radial direction of the diffracted light receiver Among the received light signals, a peak detecting means for detecting a radial position where the magnitude of the received light signal reaches a peak for each round of the predetermined angle;
Among the light reception signals acquired by the light reception signal acquisition means at the radial position for one round detected by the peak detection means, the intensity of the laser beam with which the magnitude of the light reception signal is optimum is set as the optimum laser intensity. An X-ray diffraction measuring apparatus comprising an optimum laser intensity setting means for setting. The X-ray diffraction measurement apparatus according to claim 1,
The optimum laser intensity setting unit calculates a change amount of the received light signal with respect to a change in the intensity of the laser beam in a state where the laser intensity control unit sequentially increases the intensity of the laser beam, and the received light signal When the amount of change in the magnitude of the laser beam no longer reaches a predetermined value, the intensity of the laser beam before the change is set as the optimum laser intensity, and the amount of change in the magnitude of the received light signal reaches the predetermined value. An X-ray diffraction measurement apparatus characterized by setting the maximum value of the intensity of the increased laser beam as the optimum laser intensity when there is no time to disappear. An X-ray emitter that emits X-rays toward the measurement object;
A table in which a through hole for allowing the X-rays to pass through is formed in the center;
A diffracted light receiver that is fixed to the table and has a light receiving surface that receives the diffracted light of the X-ray diffracted by the measurement object, and that records a diffraction ring that is an image of the diffracted light;
A laser light source that emits laser light and a photodetector that receives the laser light, and irradiates the light receiving surface of the diffracted light receiver with the laser light, and is emitted from the diffracted light receiver by the irradiation of the laser light. A laser detector that receives light and outputs a received light signal corresponding to the received light intensity;
Rotating means for rotating the table around the central axis of the through hole;
A rotation angle detection circuit for detecting a rotation angle from a reference position in rotation of the table by the rotation means;
Moving means for moving the table relative to the laser detection device in a direction parallel to a light receiving surface of the diffracted light receiver;
A position detection circuit for detecting a moving position of the table by the moving means;
A laser driving circuit for driving and controlling the laser light source;
An amplification circuit capable of amplifying and outputting a light reception signal from the photodetector and changing an amplification factor of the light reception signal;
In the X-ray diffraction measurement apparatus that irradiates the measurement object from the X-ray emitter and measures the diffraction ring recorded in the diffracted light receiver by the X-ray diffracted by the measurement object,
The rotation means and the moving means are controlled to rotate and move the diffracted light receiver in which the diffractive ring is recorded, so that the irradiation position of the laser light emitted from the laser detection device in the diffracted light receiver is determined. An irradiation position control means for rotating around the center of the diffracted light receiver and changing a radial distance from the center;
The rotation angle is detected while the irradiation position control means rotates the irradiation position of the laser beam in the diffracted light receiver around the center of the diffracted light receiver and changes the radial distance from the center. When the rotation angle of the table detected by the circuit is the same rotation angle, the amplification factor of the light reception signal is made the same, and the light reception signal is received each time the rotation angle of the table changes by a predetermined angle from the same rotation angle. Gain control means for controlling the amplifier circuit so that the signal gain changes;
A plurality of light reception signals from the amplifier circuit in respective states in which the rotation angle of the table is changed by the predetermined angle, each corresponding to a plurality of irradiation positions of laser light distributed in the radial direction of the diffracted light receiver Received light signal acquisition means for respectively acquiring the received light signal;
A plurality of light reception signals acquired by the light reception signal acquisition means, the rotation angles of the table being the same, and corresponding to a plurality of irradiation positions of laser light distributed in the radial direction of the diffracted light receiver Among the received light signals, a peak detecting means for detecting a radial position where the magnitude of the received light signal reaches a peak for each round of the predetermined angle;
Among the light reception signals acquired by the light reception signal acquisition means at the radial position for one round detected by the peak detection means, the amplification factor of the light reception signal at which the magnitude of the light reception signal is optimal is the optimum amplification factor. An X-ray diffraction measurement apparatus, comprising: an optimum amplification factor setting unit set as In the X-ray-diffraction measuring apparatus of Claim 3,
The optimum amplification factor setting means calculates an amount of change in the magnitude of the received light signal with respect to a change in amplification factor of the received light signal in a state where the amplification factor control means sequentially increases the amplification factor of the received light signal, When the amount of change in the received light signal does not reach a predetermined value, the amplification factor of the received light signal before the change is set as the optimum amplification factor, and the amount of change in the received light signal size is the predetermined amount. An X-ray diffraction measurement apparatus characterized in that, when there is no time when the value does not reach the value, the maximum value of the increased amplification factor of the received light signal is set as the optimum amplification factor. An X-ray emitter that emits X-rays toward the measurement object;
A table in which a through hole for allowing the X-rays to pass through is formed in the center;
A diffracted light receiver that is fixed to the table and has a light receiving surface that receives the diffracted light of the X-ray diffracted by the measurement object, and that records a diffraction ring that is an image of the diffracted light;
A laser light source that emits laser light and a photodetector that receives the laser light, and irradiates the light receiving surface of the diffracted light receiver with the laser light, and is emitted from the diffracted light receiver by the irradiation of the laser light. A laser detector that receives light and outputs a received light signal corresponding to the received light intensity;
Rotating means for rotating the table around the central axis of the through hole;
A rotation angle detection circuit for detecting a rotation angle from a reference position in rotation of the table by the rotation means;
Moving means for moving the table relative to the laser detection device in a direction parallel to a light receiving surface of the diffracted light receiver;
A position detection circuit for detecting a moving position of the table by the moving means;
A laser drive circuit capable of driving and controlling the laser light source and changing the intensity of the laser light emitted from the laser light source;
An amplification circuit capable of amplifying and outputting a light reception signal from the photodetector and changing an amplification factor of the light reception signal;
In the X-ray diffraction measurement apparatus that irradiates the measurement object from the X-ray emitter and measures the diffraction ring recorded in the diffracted light receiver by the X-ray diffracted by the measurement object,
The rotation means and the moving means are controlled to rotate and move the diffracted light receiver in which the diffractive ring is recorded, so that the irradiation position of the laser light emitted from the laser detection device in the diffracted light receiver is determined. A first irradiation position control means for rotating around the center of the diffracted light receiver and changing a radial distance from the center;
In the state where the irradiation position of the laser beam in the diffracted light receiver is rotated around the center of the diffracted light receiver and the radial distance from the center is changed by the first irradiation position control means. While maintaining the signal amplification factor constant, when the rotation angle of the table detected by the rotation angle detection circuit is the same rotation angle, the intensity of the laser beam is made the same, and the rotation angle of the table is Laser intensity control means for controlling the laser drive circuit so that the intensity of the laser beam changes every time the same rotation angle changes by a predetermined angle;
In the state where the laser intensity control means is changing the intensity of the laser beam, the received light signal from the amplifier circuit in each state where the rotation angle of the table is changed by the predetermined angle, the diffracted light receiver First received light signal acquisition means for respectively acquiring a plurality of received light signals respectively corresponding to a plurality of irradiation positions of laser light distributed in the radial direction of
A light reception signal acquired by the first light reception signal acquisition unit, the rotation angle of the table being the same, and corresponding to a plurality of irradiation positions of laser light distributed in the radial direction of the diffracted light receiver A first peak detecting means for detecting a radial position where the magnitude of the received light signal reaches a peak among the plurality of received light signals for each predetermined angle;
Of the received light signals acquired by the first received light signal acquiring means at the radial position for one round detected by the first peak detecting means, the intensity of the laser beam at which the magnitude of the received light signal is optimum is determined. An optimum laser intensity setting means for setting the optimum laser intensity;
The rotation means and the moving means are controlled to rotate and move the diffracted light receiver in which the diffractive ring is recorded, so that the irradiation position of the laser light emitted from the laser detection device in the diffracted light receiver is determined. A second irradiation position control means for rotating around the center of the diffracted light receiver and changing a radial distance from the center;
The optimum laser in a state where the irradiation position of the laser beam in the diffracted light receiver is rotated around the center of the diffracted light receiver and the radial distance from the center is changed by the second irradiation position control means. The amplification factor of the received light signal is the same when the rotation angle of the table detected by the rotation angle detection circuit is the same rotation angle while keeping the intensity of the laser beam at the optimum laser intensity set by the intensity setting means. And an amplification factor control means for controlling the amplification circuit so that the amplification factor of the received light signal changes every time the rotation angle of the table changes by a predetermined angle from the same rotation angle;
A light reception signal from the amplification circuit in each state in which the rotation angle of the table is changed by the predetermined angle while the amplification factor control means is changing the amplification factor of the light reception signal, Second received light signal acquisition means for acquiring a plurality of received light signals respectively corresponding to a plurality of irradiation positions of laser light distributed in the radial direction of the vessel;
A light reception signal acquired by the second light reception signal acquisition means, the rotation angle of the table being the same, and corresponding to a plurality of irradiation positions of laser light distributed in the radial direction of the diffracted light receiver A second peak detecting means for detecting a radial position where the magnitude of the received light signal reaches a peak among the plurality of received light signals for each predetermined angle;
Among the light reception signals acquired by the second light reception signal acquisition means at the radial position for one round detected by the second peak detection means, the amplification factor of the light reception signal at which the magnitude of the light reception signal is optimum An X-ray diffraction measuring apparatus, comprising: an optimum amplification factor setting means for setting a gain as an optimum amplification factor. In the X-ray-diffraction measuring apparatus of Claim 5,
The optimum laser intensity setting unit calculates a change amount of the received light signal with respect to a change in the intensity of the laser beam in a state where the laser intensity control unit sequentially increases the intensity of the laser beam, and the received light signal When the amount of change in the magnitude of the laser beam no longer reaches a predetermined value, the intensity of the laser beam before the change is set as the optimum laser intensity, and the amount of change in the magnitude of the received light signal reaches the predetermined value. When there was no time to disappear, set the maximum value of the intensity of the increased laser light as the optimum laser intensity,
The optimum amplification factor setting means calculates an amount of change in the magnitude of the received light signal with respect to a change in amplification factor of the received light signal in a state where the amplification factor control means sequentially increases the amplification factor of the received light signal, When the amount of change in the received light signal does not reach a predetermined value, the amplification factor of the received light signal before the change is set as the optimum amplification factor, and the amount of change in the received light signal size is the predetermined amount. An X-ray diffraction measurement apparatus characterized in that, when there is no time when the value does not reach the value, the maximum value of the increased amplification factor of the received light signal is set as the optimum amplification factor.

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