JPWO2017158912A1 - Probe for radiation measurement - Google Patents

Abstract

  The radiation measurement probe 12 includes a radiation detector 62 that converts radiation into light, a photodetector 64 that detects light and outputs a detection signal, and a front inner case as a hollow member that accommodates at least the radiation detector 62. 36. The front inner case 36 has a tip wall 115 that faces the front surface of the radiation detector 62. Due to the action of the rotating member 78 and the transmission member 80, a pressing force is applied to the rear surface of the radiation detector 62, whereby the radiation detector 62 is sandwiched between the distal end wall 115 and the distal end portion of the transmission member 80. Is done.

Description

  The present invention relates to a radiation measurement probe used for measurement of radiation.

  As a radiation measuring apparatus, a survey meter, a body surface monitor, a monitoring post, and the like are known. Some radiation measurement apparatuses include a probe that detects radiation and a main unit including a display unit that displays a measurement value of the radiation (see Patent Document 1).

  Generally, a detection unit is provided in the probe. The detection unit includes a radiation detector that converts radiation into light, and a photodetector that detects light and outputs a detection signal.

JP, 2014-153306, A

  In general, a radiation measurement probe preferably has high vibration resistance and impact resistance.

  An object of the present invention is to improve vibration resistance and impact resistance in a radiation measurement probe.

  A radiation measurement probe according to the present invention has a front surface and a rear surface spaced apart in the probe central axis direction, a radiation detector for converting radiation into light, and a front surface facing the rear surface of the radiation detector, A photodetector for detecting light and outputting a detection signal; a container as a hollow member containing at least the radiation detector, the container having a tip wall facing the front surface of the radiation detector; and the container A working end portion of the tip wall and the transmitting portion of the pressing force by providing a pressing force forwardly against the rear surface of the radiation detector. And a pressing member that allows the radiation detector to be sandwiched therebetween.

  According to the said structure, a radiation detector is clamped with the force pressed ahead. The sandwiched state is a state in which the radiation detector is fixed at least in the direction of the center axis of the probe in the container. Since the radiation detector is fixed in this way, it is possible to improve vibration resistance and impact resistance.

  Preferably, the pressing member is screwed into the container and generates a pressing force by its own rotational movement, and between the force generating member and the rear surface of the radiation detector. A transmission member that is slidably provided on the force generation member and transmits the pressing force generated by the force generation member to a rear surface of the radiation detector.

  According to the said structure, a radiation detector is clamped with the rotational motion of a rotating member.

  Preferably, the size of the rear surface of the radiation detection surface is larger than the size of the front surface of the light detection surface, an annular gap exists around the photodetector in the container, and the transmission member is It has a cylindrical portion that extends in the gap.

  According to the above configuration, the pressing force can be transmitted to the radiation detector by effectively utilizing the annular gap.

  Desirably, the front end surface of the working end portion which is the front end portion of the cylindrical portion abuts on a peripheral edge portion in the rear surface of the radiation detector.

  According to the above configuration, the pressing force is directly transmitted to the peripheral edge portion on the rear surface of the radiation detector, whereby the radiation detector is sandwiched.

  Desirably, the rear surface of the radiation detector and the front surface of the photodetector are bonded together, whereby the photodetector is fixed to the radiation detector.

  According to the above configuration, generally a heavy radiation detector is directly sandwiched and fixed, and a light and fragile light detector is generally fixed to the radiation detector, thereby directly connecting to the photodetector. It is possible to avoid excessive load application. Various methods can be used as the fixing method. For example, the rear surface of the radiation detector and the front surface of the photodetector are adhered by an adhesive sheet as an optically transparent sheet-like light guide member, thereby fixing the photodetector to the radiation detector. May be. Of course, the fixation may be realized by another configuration.

  Preferably, it further includes an annular elastic holder disposed in the cylindrical portion and elastically holding the light receiving end of the photodetector fixed to the radiation detector while wrapping.

  According to the above configuration, the impact from the side surface of the photodetector is alleviated by the elastic holder, and the vibration resistance and impact resistance can be improved.

  Preferably, the elastic holder suppresses movement of the light receiving end in a direction orthogonal to the probe central axis direction.

  According to the above configuration, the photodetector can be held at a fixed position.

  Preferably, the elastic holder has a front surface corresponding to the rear surface of the radiation detector and a rear surface opposite to the front surface, and irregularities are formed on an inner periphery and a rear surface of the elastic holder.

  According to the above configuration, the holding force by the elastic holder increases.

  According to the present invention, it is possible to improve vibration resistance and impact resistance in a radiation measurement probe.

It is a perspective view which shows the radiation measuring device which concerns on embodiment of this invention. It is a perspective view which shows the probe for radiation measurement. It is a perspective view which shows a main body unit. It is a disassembled perspective view which shows the probe for radiation measurement. It is a disassembled perspective view which shows a detection unit. It is a perspective view which shows a radiation detector. It is a perspective view which shows a radiation detector. It is sectional drawing which shows an elastic holder. It is a perspective view which shows a detection unit and a signal processing unit. It is a perspective view which shows a detection unit and a signal processing unit. It is a perspective view which shows a detection unit and a signal processing unit. It is sectional drawing which shows the probe for radiation measurement. It is sectional drawing which shows a part of probe for a radiation measurement. It is sectional drawing which shows a detection unit. It is a block diagram which shows a radiation measuring device. It is a block diagram which shows the probe for radiation measurement.

  FIG. 1 shows an example of a radiation measuring apparatus according to an embodiment of the present invention. The radiation measurement apparatus 10 includes a plurality of units, and includes a radiation measurement probe 12 and a main body unit 14. These are also basic units. The radiation measurement apparatus 10 may include an optional unit as an expansion unit, or may be connected to a personal computer (PC) as another unit.

  The radiation measurement probe 12 is a unit that detects radiation. The radiation measurement probe 12 has a cylindrical shape as a whole, and includes a front outer case 16 disposed on the front side and a rear outer case 18 disposed on the rear side. The front outer case 16 corresponds to an example of a “first outer case”, and the rear outer case 18 corresponds to an example of a “second outer case”. The front outer case 16 and the rear outer case 18 are containers as hollow members. The front surface of the front outer case 16 is a radiation detection surface 20. The front outer case 16 and the rear outer case 18 are made of a metal such as aluminum. The front outer case 16 and the rear outer case 18 constitute an outer case, and a detection unit and a signal processing unit described later are accommodated in the outer case. The rear outer case 18 is a portion that is gripped by the measurer. An operation unit 22 is provided substantially at the center of the radiation measurement probe 12. The operation unit 22 is provided with a button for the measurer to select a time constant (smoothing coefficient) and a light source (such as an LED light source) that is turned on when radiation is detected. The time constant is selected by operating the button by the measurer. In addition, the operation unit 22 may be provided with a memory button for instructing storage of the measurement value. When the memory button is operated by the measurer, the measurement value is stored in the memory in the radiation measurement probe 12 or the memory in the main unit 14. The radiation measurement probe 12 is connected to the main unit 14 by a cable 24. As will be described later, a digital signal indicating the measured value is output to the main unit 14 via the cable 24. Of course, the radiation measurement probe 12 and the main unit 14 may perform wireless communication without using the cable 24. In this case, a digital signal indicating the measurement value is transmitted from the radiation measurement probe 12 to the main unit 14 by wireless communication.

  The main unit 14 includes a display unit 26 provided on the surface of the case, a connecting unit 28, various operation buttons 30, and a connector to which the cable 24 is connected. The main unit 14 receives a digital signal indicating a measurement value from the radiation measurement probe 12 via the cable 24. The display unit 26 is a monitor such as a liquid crystal display, and the display unit 26 displays radiation measurement values and the like. The display unit 26 may be a touch panel monitor including a liquid crystal display and a touch sensor. Of course, a display without a touch sensor may be provided in the main unit 14 as the display unit 26. The radiation measuring probe 12 and the main unit 14 can be integrated by being connected via a connecting portion 28. The main unit 14 is provided with an acoustic device such as a buzzer that generates a sound when radiation is detected. The main unit 14 includes a battery, and a voltage from the battery is supplied from the main unit 14 to the radiation measurement probe 12.

  2 shows the radiation measuring probe 12 in a state separated from the main unit 14, and FIG. 3 shows the main unit 14 in the separated state. At the time of measuring radiation, the measurer usually holds the rear outer case 18 of the radiation measuring probe 12 and removes the radiation measuring probe 12 from the main unit 14 and performs measurement in that state. Of course, the measurement may be performed in a state where the radiation measurement probe 12 and the main unit 14 are connected.

  Hereinafter, each unit constituting the radiation measurement probe 12 will be described in detail with reference to FIG. FIG. 4 is an exploded perspective view showing the radiation measurement probe 12. In the present embodiment, γ rays are used as the radiation to be measured, but this is only an example. The radiation to be measured may be α rays, β rays, or neutron rays.

  The radiation measurement probe 12 includes a detection unit 32 that detects radiation and a signal processing unit 34 that processes a detection signal (electric signal) output from the detection unit. The detection unit 32 and the signal processing unit 34 are detachably connected in the axial direction of the radiation measurement probe 12. The detection unit 32 and the signal processing unit 34 are accommodated in an outer case constituted by the front outer case 16 and the rear outer case 18. The detection unit 32 is accommodated in the front outer case 16, and a part of the signal processing unit 34 is accommodated in the rear outer case 18.

  The detection unit 32 has a cylindrical shape as a whole, and includes a front inner case 36 disposed on the front side and a rear inner case 38 disposed on the rear side. The front inner case 36 and the rear inner case 38 are containers as hollow members. On the front surface 40 of the front inner case 36, an uneven structure for absorbing shock is formed. By this uneven structure, the impact transmitted from the front surface 40 is alleviated. The front inner case 36 and the rear inner case 38 are made of a resin such as polycarbonate. An inner case is constituted by the front inner case 36 and the rear inner case 38, and a radiation detector and a photodetector described later are accommodated in the inner case. Thus, the detection unit 32 is a unit in which the radiation detector and the photodetector are packaged, that is, a unit in which the radiation detector and the photodetector are encapsulated. The detection unit 32 is a component (independent replacement component) that is independently replaced. The inner case has a light shielding structure, and the radiation detector and the photodetector are arranged in a light-shielded environment. For example, the color of the front inner case 36 and the rear inner case 38 is black, and they constitute the main part of the light shielding structure. The rear end portion 42 of the rear inner case 38 is detachably connected to a signal processing unit 34 described later.

  The signal processing unit 34 includes a skeleton structure 44. The skeleton structure 44 includes a housing portion 46 and a frame portion 48. The housing portion 46 and the frame portion 48 are connected in the axial direction of the radiation measurement probe 12. The housing part 46 and the frame part 48 are made of a metal such as magnesium, for example.

  The casing portion 46 has a cylindrical shape as a whole. The casing portion 46 is provided with the operation unit 22. The front end portion 50 of the housing portion 46 and the rear end portion 42 of the detection unit 32 (rear inner case 38) mesh with each other in the circumferential direction, so that the detection unit 32 and the signal processing unit 34 can be attached and detached. Connected. In the housing portion 46, a screw groove 51 is formed along the circumferential direction on the side surface slightly rearward of the front end portion 50. A screw groove that engages with the screw groove 51 is formed on the inner periphery of the rear end portion of the front outer case 16, and both the screw grooves engage with each other, so that the front outer case 16 has the skeleton structure 44 (housing portion 46). ) Is screwed (screwed). In this way, the front outer case 16 is detachably connected to the skeleton structure 44 (housing portion 46). In a state where the front outer case 16 is coupled to the housing portion 46, the detection unit 32 is held in the front outer case 16.

  A plurality of screw holes 52 are formed on the side surface near the center of the housing portion 46. The screw hole 52 is a screw hole for detachably connecting the rear outer case 18 to the housing portion 46.

  A first substrate 54 is disposed on one side of the frame portion 48, and a second substrate 56 is disposed on the other side of the frame portion 48. The first substrate 54 and the second substrate 56 are substrates on which a circuit for processing a detection signal and a power supply circuit are provided. As will be described later, the first substrate 54 and the second substrate 56 are provided with electronic circuits. For example, the first substrate 54 is provided with a power supply circuit and a CPU, and the second substrate 56 is provided with a hybrid IC. The circuit will be described in detail later.

  A cutout portion 58 having a shape that matches the shape of the operation portion 22 is formed on the front end side of the rear outer case 18. A through hole 60 corresponding to the screw hole 52 formed in the housing portion 46 is formed on the side surface on the distal end side. The frame portion 48, the first substrate 54, and the second substrate 56 are accommodated in the rear outer case 18, and the operation portion 22 of the housing portion 46 is disposed in the cutout portion 58 of the rear outer case 18. A screw is inserted into the through hole 60 of the rear outer case 18, and the screw and the screw hole 52 are screwed (screwed together). As a result, the rear outer case 18 is attached to the skeleton structure 44 (the housing portion 46). ) Is detachably connected.

  Hereinafter, the detection unit 32 will be described in detail with reference to FIG. FIG. 5 shows the detection unit 32 in a disassembled state.

  The detection unit 32 includes a radiation detector 62 that converts radiation into light, and a photodetector 64 (light converter) that detects light and outputs a detection signal (electric signal).

  The radiation detector 62 has a cylindrical shape or a disk shape, and has a front surface 66 and a rear surface 68 that are spaced apart from each other in the central axis direction of the radiation measurement probe 12. The radiation detector 62 includes a scintillator member that converts radiation into light, and a container that houses the scintillator member. Radiation enters the scintillator member from the front surface 66, and light converted by the scintillator member exits from the rear surface 68. That is, the front surface 66 corresponds to a radiation incident surface, and the rear surface 68 corresponds to a light exit surface (light exit surface). The radiation may also enter the scintillator member from the side surface or the rear surface 68. The front inner case 36 has a tip wall that faces the front surface 66 of the radiation detector 62 in a state where the radiation detector 62 is accommodated in the front inner case 36. The tip wall corresponds to the surface on the opposite side of the front surface 40 of the front inner case 36.

  The photodetector 64 has a cylindrical shape as a whole and is provided on the rear side of the radiation detector 62 in the central axis direction of the radiation measurement probe 12. The photodetector 64 is thinner than the radiation detector 62. The photodetector 64 has a front surface 70 that faces the rear surface 68 of the radiation detector 62. The photodetector 64 is configured by, for example, a photomultiplier tube having a glass container extending in the central axis direction of the radiation measurement probe 12. The light emitted from the rear surface 68 (light exit surface) of the radiation detector 62 is incident on the light detector 64 from the front surface 70, and the detection signal (electric signal) converted by the light detector 64 is the back of the light detector 64. Output from the end. The front surface 70 of the photodetector 64 corresponds to a light receiving surface.

  The rear surface 68 (light-emitting surface) of the radiation detector 62 and the front surface 70 (light-receiving surface) of the photodetector 64 are bonded by a double-sided adhesive sheet 72 as an example of an adhesive member. Thereby, the photodetector 64 is fixed to the radiation detector 62, and the photodetector 64 is held in a cantilever manner. The double-sided adhesive sheet 72 is an optically transparent sheet-shaped (film-shaped) light guide member, and has a function of maintaining a self-shape.

  For example, the original sheet of the double-sided adhesive sheet 72 is composed of an acid-free acrylic pressure-sensitive adhesive formed in a sheet shape and peeled PET bonded to both surfaces of the acid-free acrylic pressure-sensitive adhesive. When used (adhered), the peeled PET is peeled from both sides of the original sheet, and the double-sided adhesive sheet 72 (acid-free acrylic pressure-sensitive adhesive) in a state where the peeled PET is peeled off is the rear face 68 of the radiation detector 62. And the front surface 70 of the photodetector 64. For example, the peeled PET is peeled from one surface of the original sheet, and the surface exposed by the peeling (the surface of the double-sided adhesive sheet 72 (the surface of the acid-free acrylic adhesive)) is on the rear surface 68 of the radiation detector 62. Glued. Next, the peeled PET is peeled from the other surface of the original sheet, and the front surface 70 of the photodetector 64 is exposed to the surface exposed by the peeling (the surface of the double-sided adhesive sheet 72 (the surface of the acid-free acrylic adhesive)). Is glued. Thereby, the photodetector 64 is fixed to the radiation detector 62.

  The thickness of the double-sided adhesive sheet 72 is, for example, 10 μm to 1000 μm, and preferably 75 μm to 250 μm.

The adhesive strength of the double-sided adhesive sheet 72 is 5N to 100N at 90 ° peeling, and preferably 10N to 30N. As another standard for defining the adhesive force, a tensile force (force that pulls vertically) or a shear adhesive strength may be used. For example, the tensile strength of the double-sided adhesive sheet 72 ^{is 10N / cm 2 ~150N / cm 2} . Further, the shear adhesive strength of the double-sided adhesive sheet 72 ^{is 10N / cm 2 ~150N / cm 2} . Of course, these values are merely examples, and other values may be adopted as long as the photodetector 64 is held.

  The transmittance of the double-sided adhesive sheet 72 in the light emission wavelength region of the scintillator is 50% or more, and preferably 90% or more.

  The double-sided adhesive sheet 72 has a size that covers substantially the entire rear surface 68 of the radiation detector 62. The diameter of the photodetector 64 is smaller than the diameter of the radiation detector 62, and the size of the front surface 70 (light receiving surface) of the photodetector 64 is smaller than the size of the rear surface 68 (light emitting surface) of the radiation detector 62. Therefore, when the front surface 70 and the rear surface 68 are bonded by the double-sided adhesive sheet 72, the photodetector 64 is not bonded to the rear surface of the double-sided adhesive sheet 72 (the surface facing the front surface 70 of the photodetector 64). As a part, an annular region corresponding to the periphery of the photodetector 64 is formed. An annular reflector 74 is bonded to the annular region. The diameter of the photodetector 64 is smaller than the inner diameter of the reflector 74. The reflecting material 74 is made of, for example, a porous material. The reflecting material 74 has a function of reflecting and scattering the light emitted from the annular region out of the light emitted from the rear surface 68 (light emitting surface) of the radiation detector 62 into the radiation detector 62. Thereby, even if the size of the front surface 70 (light-receiving surface) of the photodetector 64 is smaller than the size of the rear surface 68 (light-emitting surface) of the radiation detector 62, light leakage on the rear surface 68 can be prevented. Become. In the present embodiment, it is possible to bond the reflective material 74 by making good use of the rear surface of the double-sided adhesive sheet 72. In addition, the reflectance in the light emission wavelength region of the scintillator of the reflecting material 74 is 50% or more, and preferably 90% or more. The reflected wave by the reflecting material 74 is, for example, diffuse reflection or specular reflection.

An adhesive member other than the double-sided adhesive sheet 72 may be used. For example, an optical adhesive may be used as the adhesive member. Examples of the optical adhesive include a UV curable (ultraviolet curable) optical adhesive, a thermosetting optical adhesive, a room temperature curable optical adhesive, and a mixed optical adhesive (for example, 2). An adhesive that is cured by mixing the liquid) is used. As an example of the optical adhesive, an acid-free acrylic adhesive is used. Like the double-sided adhesive sheet 72, the tensile force of the optical adhesive ^{is 10N / cm 2 ~150N / cm 2} , a shear adhesive strength of the optical adhesive ^{is 10N / cm 2 ~150N / cm 2} . Of course, these values are merely examples, and other values may be adopted as long as the photodetector 64 is held. When an optical adhesive is used as the adhesive member, depending on the selected optical adhesive, the optical adhesive may permeate the reflective material 74 and reduce the reflective power of the reflective material 74 in some cases. For example, when an optical adhesive that takes a relatively long time to cure is used, the optical adhesive may penetrate into the reflector 74. In this case, occurrence of such a problem can be prevented by using the double-sided adhesive sheet 72 instead of the optical adhesive. As another example, by using an optical adhesive that requires a relatively short time for curing, the optical adhesive on the reflector 74 can be used compared to the case where an optical adhesive that requires a relatively long time is used. It is possible to suppress or prevent soaking, and as a result, it is possible to suppress or prevent a decrease in the reflectivity of the reflecting material 74. The transmittance of the optical adhesive in the light emission wavelength region of the scintillator is 50% or more, and preferably 90% or more.

Incidentally, the tensile force of the common optical grease is about 3.0 N / cm ^2, for shear adhesive strength is about 1.5 N / cm ^2, light detector to the radiation detector 62 by an optical grease 64 It is difficult to fix. If optical grease is used, the photodetector 64 is easily peeled off from the radiation detector 62. On the other hand, the photodetector 64 can be fixed to the radiation detector 62 by using the double-sided adhesive sheet 72 or the optical adhesive as in this embodiment.

  An annular elastic holder 76 is attached to the photodetector 64. The elastic holder 76 is a member that elastically holds the light receiving end portion (end portion on the front surface 70 side) of the photodetector 64 fixed to the radiation detector 62 while wrapping from the side surface side of the photodetector 64. The elastic holder 76 has a function of suppressing the movement of the light receiving end (photodetector 64) in the direction orthogonal to the central axis direction of the radiation measurement probe 12. The elastic holder 76 is made of a rubber material such as silicone rubber. The color of the elastic holder 76 is, for example, white, and has a function of reflecting light. The elastic holder 76 has a front surface 76a facing the rear surface 68 (light-emitting surface) of the radiation detector 62 and a rear surface 76b opposite to the front surface 76a. Concavities and convexities are formed on the inner peripheral surface and the rear surface 76 b of the elastic holder 76. The outer diameter of the elastic holder 76 is smaller than the inner diameter of the front inner case 36. Due to the uneven shape, the dimensional tolerance of the photodetector 64 and the like is absorbed. Moreover, elastic force increases further by crushing and using the uneven | corrugated shape.

  The detection unit 32 includes a rotating member 78 that functions as a force generating member and a transmission member 80 as a non-rotating member. The rotating member 78 and the transmission member 80 function as a pressing member that applies a pressing force to the peripheral portion of the rear surface 68 of the radiation detector 62 toward the front (the front surface 40 side of the front inner case 36). By the pressing, the front end wall of the front inner case 36 (the surface facing the front surface 66 of the radiation detector 62, that is, the surface on the opposite side of the front surface 40 of the front inner case 36) and the working end portion of the pressing force transmitting portion. The radiation detector 62 is sandwiched between the two.

  The rotating member 78 includes a main body portion 82 having a cylindrical shape and an annular member 84 provided at one end of the main body portion 82. The diameter of the annular member 84 is larger than the diameter of the main body portion 82 and is substantially equal to the inner diameter of the front inner case 36. A thread groove is formed on the side surface of the annular member 84, and a thread groove that meshes with the thread groove is formed on the inner periphery of the rear end portion of the front inner case 36. The rotating member 78 is screwed (screwed) to the inner periphery of the front inner case 36 by engaging both screw grooves. The inner diameter of the rotating member 78 (the main body 82 and the annular member 84) is larger than the outer diameter of the photodetector 64, and the photodetector 64 is inserted into the rotating member 78 and penetrates the rotating member 78. That is, the photodetector 64 is inserted through the rotating member 78. The rotary member 78 is screwed (screwed) to the front inner case 36 and generates a force that presses forward against the peripheral edge of the rear surface 68 of the radiation detector 62 by its own rotational movement.

  The transmission member 80 is provided so as to be able to slip with respect to the rotation member 78 between the rotation member 78 and the rear surface 68 of the radiation detector 62, and transmits the pressing force generated by the rotation member 78 to the radiation detector 62. is there. Specifically, the transmission member 80 has a cylindrical shape. The inner diameter of the transmission member 80 is larger than the outer diameters of the photodetector 64, the double-sided adhesive sheet 72, the reflector 74, and the elastic holder 76. Therefore, the double-sided adhesive sheet 72, the reflective material 74, and the elastic holder 76 are disposed in the transmission member 80. The outer diameter of the transmission member 80 is substantially equal to the outer diameter of the rear surface 68 of the radiation detector 62. As described above, the outer diameter of the photodetector 64 is smaller than the outer diameter of the radiation detector 62. Therefore, when the radiation detector 62 and the photodetector 64 are accommodated in the front inner case 36, an annular gap is formed around the photodetector 64 in the front inner case 36, and the transmission member 80 is The annular gap is disposed. The distal end portion 80 a of the transmission member 80 corresponds to the action end portion of the pressing force, and abuts on the peripheral edge portion of the rear surface 68 of the radiation detector 62. The rear end portion 80b of the transmission member 80 is provided with a surface that contacts the front surface of the annular member 84 of the rotating member 78, and a through-hole through which the photodetector 64 is inserted is formed on the surface. ing. The photodetector 64 is inserted through the through hole. The size of the diameter of the through hole is equal to the size of the inner diameter of the rotating member 78. The annular member 84 of the rotating member 78 contacts the surface of the rear end portion 80 b of the transmission member 80, and the front end portion 80 a of the transmission member 80 contacts the peripheral portion of the rear surface 68 of the radiation detector 62. Thereby, the pressing force generated by the rotating member 78 is directly transmitted to the peripheral edge portion of the radiation detector 62 via the transmission member 80.

  An impact absorbing plate 86 is provided between the front surface 66 of the radiation detector 62 and the tip wall of the front inner case 36 (surface opposite to the front surface 40). The shock absorbing plate 86 is an elastic member and is made of, for example, a resin such as silicone. Of course, the shock absorbing plate 86 may not be provided. The impact absorbing plate 86 reduces the impact on the front surface of the radiation measurement probe 12.

  A bleeder substrate 88 is connected to the rear end of the photodetector 64 (the end opposite to the front surface 70 side). The bleeder substrate 88 is provided with a socket 89, and the socket 89 is connected to the rear end of the photodetector 64. A signal line 90 is connected to the bleeder substrate 88, and a connector 92 is connected to the end of the signal line 90. As will be described later, the connector 92 is connected to a connector provided in the signal processing unit 34. The detection signal (electric signal) output from the photodetector 64 is output to the signal processing unit 34 via the signal line 90 and the connector 92.

  An insulating sponge 94 having an insulating function is installed on the bleeder substrate 88. A center hole 95 and a slit 96 (break) are formed in the insulating sponge 94, and the signal line 90 is disposed in the center hole 95 through the slit 96.

  The cap 98 is a member constituting the light shielding structure of the inner case, and is provided at the rear end portion 42 of the rear inner case 38. Thereby, the opening of the rear end portion 42 is sealed, and light shielding is realized at the rear end portion 42. That is, the incidence of light from the back surface of the inner case into the inner case is blocked. The cap 98 is made of an elastic member such as a rubber member. The cap 98 functions as a rubber stopper for the opening. The color of the cap 98 is black. The cap 98 has a center hole 99 and a slit 100 (break), and the signal line 90 is disposed in the center hole 95 through the slit 100.

  A thread groove 102 is formed along the circumferential direction on the side surface of the rear inner case 38 on the front end side (the end opposite to the rear end 42). A screw groove that engages with the screw groove 102 is formed on the inner periphery of the rear end portion of the front inner case 36, and both the screw grooves engage with each other, whereby the rear inner case 38 is screwed (screwed) to the front inner case 36. ) In this way, the front inner case 36 and the rear inner case 38 are detachably connected.

  Hereinafter, the radiation detector 62 will be described in detail with reference to FIGS. 6 and 7. 6 and 7 are perspective views showing the radiation detector 62. FIG.

As shown in FIG. 6, the radiation detector 62 includes a scintillator member 104 that converts radiation into light, and a container 106 that houses the scintillator member 104. The scintillator member 104 is composed of, for example, NaI, CsI, BGO, GSO, GAGG, LaBr ₃ , SrI ₂ , plastic scintillator, and the like. The container 106 is made of a metal such as aluminum. The container 106 has a peripheral edge 108. The distal end portion 80 a of the transmission member 80 contacts the peripheral edge portion 108 of the container 106. Thereby, the pressing force generated by the rotating member 78 is directly transmitted to the peripheral edge 108 of the container 106. As described above, the double-sided adhesive sheet 72 is adhered to the rear surface 68 (light-emitting surface) of the radiation detector 62, whereby the photodetector 64 is fixed to the radiation detector 62.

  FIG. 7 shows the radiation detector 62 with the double-sided adhesive sheet 72 adhered thereto. As described above, the annular reflecting material 74 is bonded to the double-sided adhesive sheet 72. The photodetector 64 is bonded to the double-sided adhesive sheet 72 through a circular portion inside the reflector 74.

  Next, the elastic holder 76 will be described in detail with reference to FIG. FIG. 8 is a cross-sectional view showing the elastic holder 76. Concavities and convexities 110 are formed on the inner peripheral surface of the elastic holder 76, and concavities and convexities 112 are formed on the rear surface 76b.

  Hereinafter, the connection state of the detection unit 32 and the signal processing unit 34 will be described with reference to FIGS. 9 to 11 are perspective views of the detection unit 32 and the signal processing unit 34, and FIGS. 10 and 11 show partial cross sections thereof.

  The signal processing unit 34 includes a connector 114 that is detachably connected to the connector 92 of the detection unit 32. The connector 114 is disposed on the second substrate 56. The detection signal (electric signal) output from the photodetector 64 of the detection unit 32 is output to the second substrate 56 of the signal processing unit 34 via the connectors 92 and 114. The connector 92 corresponds to an example of a first connector, and the connector 114 corresponds to an example of a second connector.

  As shown in FIG. 11, the rear end portion 42 of the rear inner case 38 of the detection unit 32 and the front end portion 50 of the housing portion 46 of the signal processing unit 34 are engaged with each other in the circumferential direction. The detection unit 32 and the signal processing unit 34 are connected.

  Hereinafter, the radiation measurement probe 12 in a state where the respective components are assembled will be described in detail with reference to FIGS. 12 to 14. FIG. 12 is a cross-sectional view showing the radiation measurement probe 12, and FIG. 13 shows a part thereof. FIG. 14 is a cross-sectional view showing the detection unit 32.

  A radiation detector 62 is accommodated in the front inner case 36. The outer diameter of the radiation detector 62 is substantially equal to the inner diameter of the front inner case 36.

  The front inner case 36 has a tip wall 115 that faces the front surface 66 of the radiation detector 62. An impact absorbing plate 86 is provided between the tip wall 115 and the front surface 66 of the radiation detector 62.

  The rear surface 68 of the radiation detector 62 and the front surface 70 of the photodetector 64 are bonded together by a double-sided adhesive sheet 72, whereby the photodetector 64 is fixed to the radiation detector 62. An annular reflector 74 is bonded to the rear surface of the double-sided adhesive sheet 72. An annular elastic holder 76 is attached to the light receiving end portion (the end portion on the front surface 70 side) of the photodetector 64. The double-sided adhesive sheet 72, the reflector 74 and the elastic holder 76 are also accommodated in the front inner case 36. The front surface 70 side of the radiation detector 62 is accommodated in the front inner case 36, and the rear end portion side of the radiation detector 62 is accommodated in the rear inner case 38.

  The outer diameter of the photodetector 64 and the outer diameter of the elastic holder 76 are smaller than the inner diameter of the front inner case 36. Therefore, an annular gap is formed between the photodetector 64 and the front inner case 36 and between the elastic holder 76 and the front inner case 36. The transmission member 80 is disposed in the annular gap. In this way, the transmission member 80 is arranged by effectively utilizing the annular gap, and the pressing force is transmitted to the radiation detector 62. Specifically, with the elastic holder 76 attached to the light detector 64, the light detector 64 fixed to the radiation detector 62 is inserted into the cylindrical transmission member 80. As a result, the transmission member 80 is attached, and the distal end portion 80a of the transmission member 80 comes into contact with the peripheral portion of the radiation detector 62 (the peripheral portion 108 of the container 106). An elastic holder 76 is disposed in the transmission member 80. The transmission member 80 is also accommodated in the front inner case 36. The outer diameter of the transmission member 80 is substantially equal to the inner diameter of the front inner case 36.

  The rotating member 78 is attached to the front inner case 36 in a state where the transmission member 80 is accommodated in the front inner case 36. Specifically, the photodetector 64 is inserted into the rotating member 78 with the photodetector 64 inserted through the transmission member 80. As described above, the thread groove is formed on the side surface of the annular member 84 of the rotating member 78. A thread groove 116 that engages with the thread groove of the annular member 84 is formed on the inner periphery of the rear end portion of the front inner case 36. The outer diameter of the annular member 84 is substantially equal to the inner diameter of the front inner case 36. Therefore, by inserting the rotating member 78 into the front inner case 36 and rotating the rotating member 78, both screw grooves are engaged (screwed together), whereby the rotating member 78 is attached to the front inner case 36. . When the rotating member 78 is rotated in the attaching direction (tightening direction), the rotating member 78 moves in front of the radiation measurement probe 12 (direction indicated by the arrow X), and the front surface of the annular member 84 of the rotating member 78 is transmitted. It contacts the rear end 80b of the member 80. When the rotating member 78 is further rotated in the tightening direction, the rotating member 78 moves further forward (in the direction indicated by the arrow X) and presses the transmission member 80 forward. That is, when the rotating member 78 rotates, a force that presses the transmission member 80 forward is generated. Since the distal end portion 80 a of the transmission member 80 is in contact with the peripheral portion of the radiation detector 62 (the peripheral portion 108 of the container 106), the force generated by the rotating member 78 is transmitted via the transmission member 80 to the radiation detector. 62 is transmitted to the peripheral edge 108. As a result, the radiation detector 62 is pressed forward and is sandwiched between the distal end wall 115 of the front inner case 36 and the distal end portion 80 a of the transmission member 80. The distal end portion 80a of the transmission member 80 corresponds to the distal end portion of the acting end portion of the pressing force.

  The sandwiched state of the radiation detector 62 is a state in which the radiation detector 62 is fixed in the center axis direction of the radiation measurement probe 12 in the front inner case 36. For example, a gap 118 is formed between the inner peripheral surfaces of the rotating member 78 and the transmission member 80 and the photodetector 64, and the photodetector 64 is held in a cantilever manner.

  In the sandwiched state, the elastic holder 76 is pressed forward by the transmission member 80, and the front surface 76 a of the elastic holder 76 is in close contact with the reflector 74.

  A bleeder substrate 88 is connected to the rear end portion of the photodetector 64 through a socket 89. An insulating sponge 94 is installed on the bleeder substrate 88.

  The screw groove 102 formed on the side surface on the front end side of the rear inner case 38 and the screw groove 116 formed on the inner periphery of the rear end portion of the front inner case 36 are engaged (screwed), thereby The front inner case 36 and the rear inner case 38 are connected.

  A cap 98 is fitted into the opening of the rear end portion 42 of the rear inner case 38, thereby sealing the opening of the rear end portion 42. The front surface of the cap 98 is in contact with the insulating sponge 94 and has a shape sandwiching the insulating sponge 94. The insulating sponge 94 is lightly pressed by the cap 98, and thereby the rear end portion of the photodetector 64 is lightly pressed. The cap 98 is crushed in a state where the detection unit 32 is connected to the signal processing unit 34. Thereby, the light shielding property at the rear end portion 42 of the rear inner case 38 is improved.

  In order to ensure sealing performance, a connecting portion between the detection unit 32 and the signal processing unit 34, that is, a connecting portion between the rear end portion 42 of the rear inner case 38 and the front end portion 50 of the housing portion 46 is provided. , O-ring is installed. In addition, O-rings are also installed at the connecting portion between the front outer case 16 and the housing portion 46 of the signal processing unit 34 and at the connecting portion between the rear outer case 18 and the housing portion 46 of the signal processing unit 34. ing.

  As described above, the radiation measurement probe 12 according to the present embodiment includes the detection unit 32 and the signal processing unit 34, which are detachably connected. The detection unit 32 is a packaged (encapsulated) unit and is an independently replaceable part. As a result, the detection unit 32 can be exchanged, and its handling is easy. Therefore, it is possible to improve the maintainability of the radiation measurement probe 12. Further, it is possible to realize the radiation measuring probe 12 having different functions only by exchanging the detection unit 32, and convenience is increased. For example, by exchanging the detection unit 32, it is possible to realize the radiation measurement probe 12 for α rays, β rays, γ rays, or neutron rays. As another example, it is also possible to realize a radiation measurement probe 12 compatible with high sensitivity and high count rate.

  The inner case constituted by the front inner case 36 and the rear inner case 38 has a light shielding structure. Therefore, the light shielding property is ensured in the environment where the radiation detector 62 and the photodetector 64 are arranged. For example, even when the outer case constituted by the front outer case 16 and the rear outer case 18 is removed, the light shielding property to the radiation detector 62 and the photodetector 64 is ensured. Therefore, the outer case is removed while the detection unit 32 and the signal processing unit 34 are connected, and in this state, the measurer can perform radiation measurement while checking the appearance and circuit configuration of the signal processing unit 34. It becomes possible. In addition, circuit probing using an oscilloscope or multimeter is possible. For example, it is convenient during maintenance. A cap 98 is installed in the opening of the rear end portion 42 of the rear inner case 38. With this cap, light shielding is ensured in the rear opening of the inner case.

  Further, according to the present embodiment, the rear surface 68 (light-emitting surface) of the radiation detector 62 and the front surface 70 (light-receiving surface) of the photodetector 64 are bonded by the optically transparent double-sided adhesive sheet 72 or the optical adhesive. Thereby, it becomes possible to maintain the optical coupling between both surfaces well. Further, by fixing the generally light and fragile photodetector 64 to the generally heavy radiation detector 62, it is possible to prevent an excessive load from being applied to the photodetector 64. Moreover, since the double-sided adhesive sheet 72 or the optical adhesive has the above-described tensile force and shear adhesive strength, it is possible to improve vibration resistance and impact resistance. That is, since the photodetector 64 is positively fixed to the radiation detector 62 by the double-sided adhesive sheet 72 or the optical adhesive, the occurrence of a phenomenon such as displacement and peeling is suppressed and the radiation detector 62 is suppressed. It is possible to maintain good optical coupling between the optical detector and the photodetector 64. Further, since the total light transmittance of the double-sided adhesive sheet 72 or the optical adhesive is 50% or more, preferably 90% or more, good optical coupling can be obtained. Further, the reflecting material 74 can prevent light leakage at the rear surface 68 of the radiation detector 62.

  Further, since the photodetector 64 is held by the elastic holder 76, the impact from the direction orthogonal to the central axis of the radiation measurement probe 12 is reduced by the elastic holder 76. For example, the elastic holder 76 can suppress the movement of the photodetector 64 in the orthogonal direction. Thereby, the vibration resistance and impact resistance of the radiation measurement probe 12 can be improved. The unevenness formed in the elastic holder 76 can increase the force for holding the photodetector 64.

  In the present embodiment, the radiation detector 62 is held by the pressing force generated by the rotating member 78. Thereby, since the radiation detector 62 is fixed, it becomes possible to improve vibration resistance and impact resistance. Generally, a heavy radiation detector 62 is directly sandwiched and fixed, and a light and fragile light detector 64 is generally fixed to the radiation detector 62, thereby directly connecting the light detector 64 to the light detector 64. It is possible to avoid excessive load loading.

  Further, since no pressing force is applied to the bleeder substrate 88 and the socket 89, they are protected.

  Next, the function of the radiation measuring apparatus 10 will be described with reference to FIG. FIG. 15 is a block diagram showing the radiation measuring apparatus 10.

  As described above, the radiation measurement probe 12 includes the detection unit 32 and the signal processing unit 34. As described above, the detection unit 32 includes the scintillator member 104 and the photodetector 64. The photodetector 64 is constituted by, for example, a photomultiplier tube. The detection unit 32 converts the energy of radiation (for example, γ rays) into a detection signal (electric signal). Specifically, as described above, radiation is converted into light by the scintillator member 104, and light is converted into a detection signal by the photodetector 64 (photomultiplier tube). The detection signal is output to the calculation unit 120 of the signal processing unit 34.

  The signal processing unit 34 includes a calculation unit 120 and a high voltage generation unit 122.

  The computing unit 120 applies signal processing to the detection signal output from the detection unit 32. Thereby, a measured value (for example, dose rate Sv / h, Gy / h, integrated dose, etc.) is calculated. The signal indicating the measured value is a digital signal, and the digital signal is output to the main unit 14 via the cable 24.

  The high voltage generation unit 122 generates a high voltage (HV) under the control of the calculation unit 120 and supplies the high voltage to the photodetector 64 (photomultiplier tube) of the detection unit 32. Thereby, the photodetector 64 (photomultiplier tube) is driven.

  The main unit 14 includes a display unit 26 and a control unit 124. The control unit 124 controls display on the display unit 26, communication, and the like. The control unit 124 receives the digital signal output from the radiation measurement probe 12 and causes the display unit 26 to display the measurement value indicated by the digital signal.

  Hereinafter, the function of the radiation measurement probe 12 will be described with reference to FIG. FIG. 16 is a block diagram showing the radiation measurement probe 12.

  The radiation measurement probe 12 includes an MCA unit 126 and a CPU-HV unit 128. The MCA unit 126 is disposed on the second substrate 56 of the signal processing unit 34, and the CPU-HV unit 128 is disposed on the first substrate 54 of the signal processing unit 34 (see FIGS. 4 and 12, etc.).

  Radiation is converted into light by the scintillator member 104 (for example, NaI), light is converted into a detection signal (electric signal) by the photodetector 64 (PMT), and the detection signal is transmitted to the MCA unit 126 via the bleeder substrate 88 Is output. In addition to the combination of the scintillator member 104 and the photodetector 64, a GM tube, a combination of the scintillator member 104 and a photon measurement device (for example, SiPM (Silicon Photomultipliers)), a semiconductor detector, or the like may be used.

  The MCA unit 126 has a function of generating a spectrum of radiation by applying signal processing to the detection signal output from the photodetector 64. The CPU-HV unit 128 calculates a measured value (for example, a dose rate such as Sv / h or Gy / h, an integrated dose, etc.) by performing energy compensation on the spectrum according to the energy characteristics of the detection unit 32. It has a function to do. Further, the CPU-HV unit 128 has a function of supplying a driving voltage to the photodetector 64.

  Hereinafter, the MCA unit 126 will be described in detail.

  The MCA unit 126 includes a hybrid IC 130, a temperature sensor 132 that detects a temperature, an EEPROM 134 that functions as a storage unit, and a signal generation unit 136 that generates a buzzer signal. The hybrid IC 130 is configured by, for example, an ASIC (Application Specific Integrated Circuit).

  The hybrid IC 130 includes an analog processing circuit and a digital processing circuit, and is a circuit that generates a spectrum of radiation by applying signal processing to the detection signal output from the detection unit 32. The hybrid IC 130 includes an HV control unit 138, an AMP 140 as an analog signal processing circuit, an ADC 142 as a conversion circuit, an MCA 144, an ADC 146 as a digital signal processing circuit, and a communication unit 148. The hybrid IC 130 receives a clock signal and a reset signal. The hybrid IC 130 can adjust various adjustments related to analog circuits, such as gain of the AMP 140, shaping time, pole zero adjustment, LLD (Low Level Discriminator), offset, and the like, according to instructions from the CPU 150 described later.

  The HV control unit 138 is a control circuit that performs control of voltage generated by the HV circuit 152 described later, monitoring of voltage and current, and the like.

  The AMP 140 is an amplifier circuit that performs analog signal processing on the detection signal. Specifically, the AMP 140 amplifies and shapes the detection signal.

  The ADC 142 is a circuit that performs digital signal processing on the detection signal after analog signal processing. Specifically, the ADC 142 converts the amplified and shaped detection signal (analog signal) output from the AMP 140 into a digital signal. For example, the ADC 142 digitizes (digitalizes) the wave height (voltage) of the analog signal.

  The MCA 144 (multichannel analyzer) is a circuit that generates a radiation spectrum (frequency distribution) by storing a digitized count value for each peak value.

  The temperature is converted into a voltage by the temperature sensor 132, and this voltage is converted into a digital value by the ADC 146 to obtain a temperature value. The AMP 140 can automatically adjust the gain according to the temperature value. Thereby, temperature compensation is performed on the detection signal. The scintillator member 104 and the photodetector 64 (PMT) have temperature dependency, and the output from them changes depending on the temperature of the surrounding environment, and the output (peak value) of the MCA 144 changes. Thus, the crest value has temperature dependence. In the present embodiment, the gain of the AMP 140 is adjusted according to the detected temperature, whereby the temperature characteristic of the detection unit 32 is compensated at the stage of analog signal processing. When compensation is performed at the stage of digital signal processing, for example, when temperature compensation is performed on an output signal from the MCA 144, it is necessary to individually perform temperature compensation on multi-channel data, which makes the processing complicated. Become. On the other hand, in this embodiment, since temperature compensation is performed at the stage of analog signal processing, the complexity can be avoided. For example, when temperature compensation is performed on a digital value output from the ADC 142, a wave height greater than or equal to the maximum value of the ADC is treated as an ADC maximum value. Since it is stored in the channel below the value, inconsistency occurs in the behavior above the maximum value, and handling becomes complicated. In addition, since the discrete value multiplied by the discrete value is input to the MCA 144, spectrum continuity may be impaired. In this embodiment, such a problem can be avoided.

  Since hybrid IC 130 is a heating element, it is desirable to keep temperature sensor 132 as far as possible from hybrid IC 130. Further, it is desirable to arrange the temperature sensor 132 in the vicinity of the radiation detector 62 and the photodetector 64.

  The communication unit 148 is a circuit that communicates with the CPU 150 by serial communication, for example. The radiation spectrum (digital signal) output from the MCA 144 is output to the CPU 150 via the communication unit 148.

  The EEPROM 134 is a memory and stores data indicating a set value group of the hybrid IC 130 and a function for temperature compensation. Since the hybrid IC 130 includes an analog circuit, values such as shaping, gain, pole zero adjustment, LLD, and offset, which are parameters determined by circuit constants or the like in a normal discrete circuit, can be stored in the EEPROM as set values.

  The signal generation unit 136 generates a buzzer signal as a digital signal based on an output (for example, a detection signal) from the hybrid IC 130. The buzzer signal is output to the main unit 14 via the cable 24. In the main unit 14, the control unit 124 generates sound from the buzzer according to the buzzer signal. Thereby, when radiation is detected, a sound is emitted from the buzzer, and the measurer can recognize the detection of radiation. Since the buzzer signal is output to the main unit 14 without going through the CPU-HV unit 128, it is possible to improve the real-time property regarding the notification of radiation detection. Further, the buzzer signal is output to the CPU 150 included in the CPU-HV unit 128.

  Hereinafter, the CPU-HV unit 128 will be described in detail.

  The CPU-HV unit 128 includes a CPU (Central Processing Unit) 150, an HV circuit 152, and a communication driver 154. The CPU 150 receives a clock signal and a reset signal.

  The CPU 150 applies an energy compensation process according to the energy characteristics of the detection unit 32 to the radiation spectrum output from the hybrid IC 130, so that a measured value (for example, a dose rate such as Sv / h or Gy / h, an integrated value). Dose). Specifically, the CPU 150 applies the compensation function G (E) corresponding to the detection unit 32 to the radiation spectrum. The compensation function G (E) is changed according to the type of the scintillator member 104. Data indicating the compensation function G (E) may be stored, for example, in the internal memory of the CPU 150, may be stored in the EEPROM 134, or may be stored in another memory.

  The signal indicating the measurement value calculated by the CPU 150 is a digital signal as display information. The digital signal (display information) is output to the main unit 14 via the communication driver 154 and the cable 24. In the main unit 14, the control unit 124 causes the display unit 26 to display the measurement value based on the digital signal. As described above, the measurement value is calculated in the radiation measurement probe 12, and the measurement value calculated in the radiation measurement probe 12 is displayed on the main body unit 14. A signal indicating the spectrum of radiation may be output from the radiation measurement probe 12 to the main unit 14.

  In addition, the CPU 150 smoothes the dose rate or the count rate generated from the radiation spectrum according to the time constant (smoothing coefficient), thereby generating smoothed display information (digital signal) as display information. . The time constant is selected by a measurer, for example. The operation unit 22 is connected to the CPU 150. When the measurer operates the operation unit 22 and selects a time constant, the CPU 150 performs a smoothing process using the time constant selected by the measurer. Alternatively, the time constant may be automatically selected.

  Further, when receiving a buzzer signal from the signal generation unit 136 of the MCA unit 126, the CPU 150 turns on a light source such as an LED light source provided in the operation unit 22. Accordingly, when radiation is detected, the light source is turned on, and the measurer can recognize the detection of the radiation.

  In addition, when a memory button provided on the operation unit 22 is operated by the operator, the CPU 150 stores the measurement value in a memory (not shown).

  The energy compensation process and the smoothing process are realized by executing a program. For example, a program for energy compensation processing and a program for smoothing processing are stored in the internal memory of the CPU 150, the EEPROM 134, or another memory. Energy compensation is realized by the CPU 150 executing a program for energy compensation processing. Similarly, the smoothing process is realized by the CPU 150 executing a program for the smoothing process.

  The hybrid IC 130 and the CPU 150 constitute the arithmetic unit 120 shown in FIG.

  The HV circuit 152 is a power supply circuit that generates a drive voltage by a boosting process and supplies the drive voltage to the photodetector 64 (photomultiplier tube). The HV control unit 138 described above monitors the voltage supplied from the HV circuit 152 and controls the HV circuit 152 so that a drive voltage having a predetermined voltage value is supplied from the HV circuit 152. Note that the ON / OFF control of the HV circuit 152 is performed by the CPU 150. Of course, the HV control unit 138 may perform ON / OFF control of the HV circuit 152, and the CPU 150 may control the drive voltage supplied from the HV circuit 152. The HV circuit 152 corresponds to an example of the high voltage generation unit 122 illustrated in FIG.

  The communication driver 154 is a driver for realizing communication between the CPU 150 and the main unit 14, and has a function of performing packet communication, for example. Thereby, packet communication is realized between the CPU 150 and the main unit 14, and a digital signal (display information) indicating a measured value is transmitted to the main unit 14 by packet communication. As an example, the communication driver 154 is a driver that complies with a standard such as the RS422 standard, the RS485 standard, the RS232C standard, or the USB standard.

  The CPU-HV unit 128 includes, as an example of a power supply, a 5.0V power supply that functions as an LDO (Low Drop Out) circuit and a 2.5V power supply that functions as a DC-DC converter. For example, voltages of 5.4 V and 3.3 V are supplied from the main unit 14 to the CPU-HV unit 128.

  When the detection unit 32 is replaced, the temperature compensation function, the energy compensation function G (E), and the drive voltage (HV level) are changed. For example, a personal computer (PC) may be connected to the radiation measurement probe 12 or the main unit 14, and the temperature compensation function, energy compensation function G (E), and drive voltage level may be changed using the PC. .

  In addition, the wiring on the MCA unit 126 and the CPU-HV unit 128 can be provided with intermediate input lines or intermediate branch lines, and other circuits can be connected to the intermediate input lines or intermediate branch lines to expand the circuit functions. You may do it. The hybrid IC 130 can handle halfway input lines and halfway branch lines for analog signals.

  Hereinafter, operations of the MCA unit 126 and the CPU-HV unit 128 will be described. The drive voltage generated by the HV circuit 152 is supplied to the photodetector 64 (PMT) via the bleeder substrate 88. When radiation is detected by the scintillator member 104 (NaI), the radiation is converted into light by the scintillator member 104, and light is converted into a detection signal (analog signal) by the photodetector 64 (PMT). ) Is output to the MCA unit 126. A detection signal (analog signal) superimposed on the drive voltage is C-cut by the capacitor C and output to the hybrid IC 130. In the hybrid IC 130, the detection signal (analog signal) is amplified and shaped by the AMP 140, the detection signal (analog signal) is converted to a digital signal by the ADC 142, and the digitized count value for each peak value is stored in the MCA 144. A radiation spectrum (frequency distribution) is generated. The temperature is converted into a voltage by the temperature sensor 132, and this voltage is converted into a digital value by the ADC 146 to obtain a temperature value. Temperature compensation is performed by setting a gain corresponding to the temperature value in the AMP 140. The generated spectrum is output to the CPU 150 by digital communication of the communication unit 148. In the CPU 150, an energy compensation process using an energy compensation function G (E) is applied to the radiation spectrum, whereby a measured value (for example, a dose rate such as Sv / h or Gy / h, an integrated dose, etc.). ) Is calculated. Also, a smoothing process is applied to the radiation spectrum or the measured value according to the time constant. A digital signal indicating the measured value is a signal as display information, and is output to the main unit 14 via the communication driver 154. In the main unit 14, the measured value is displayed on the display unit 26 according to the digital signal.

  As described above, in the radiation measurement apparatus 10 according to the present embodiment, the signal processing unit 34 (MCA unit 126 and CPU-HV unit 128) is built in the radiation measurement probe 12, and the radiation measurement probe 12 is incorporated. In Fig. 4, the process from the radiation detection to the calculation of the measurement value (dose rate) is performed. As described above, the radiation measurement probe 12 according to the present embodiment is a highly functional probe having completeness in which processes from radiation detection to measurement value calculation are performed. Of course, the main body unit 14 may display the spectrum of the radiation, and the main body unit 14 may apply processing to the spectrum of the radiation.

  According to the radiation measurement apparatus 10 according to the present embodiment, it is not necessary to perform measurement value calculation processing in the main body unit 14, and thus it is possible to use the main unit 14 with high versatility. For example, it is possible to use the main unit 14 that does not depend on the type of radiation to be detected (α rays, β rays, γ rays, neutron rays).

  Further, since the drive voltage for the photodetector 64 is generated in the radiation measurement probe 12, it is not necessary to supply the drive voltage from the main unit 14 to the radiation measurement probe 12 via the cable 24. Therefore, a digital signal indicating a measurement value can be output from the radiation measurement probe 12 to the main unit 14 without being affected by noise due to the drive voltage. Moreover, it becomes possible to avoid the influence of noise on the analog signal as the detection signal. Since an analog signal and a high voltage are not passed through the cable 24, it is possible to relax restrictions on the handling and length of the cable 24.

  Further, since temperature compensation is performed by the radiation measurement probe 12, it is possible to improve the measurement accuracy of radiation.

  Further, the radiation measurement probe 12 is a probe having completeness to perform from radiation detection to measurement value calculation. Therefore, when the radiation measurement probe 12 is replaced, readjustment of the main body unit 14 becomes unnecessary, or the trouble of readjustment is reduced, and the maintainability is improved. Further, since the adjustment value is stored in the EEPROM 134 of the radiation measurement probe 12 or the internal memory of the CPU 150, the maintainability is also improved in this respect.

  Further, by adopting the hybrid IC 130, the electronic circuit can be reduced in size and size. Only the hybrid IC 130 can perform analog signal processing to spectrum generation processing.

  Further, by performing the energy compensation process by the CPU 150 that executes the program, the energy compensation function can be easily switched or exchanged according to the detection unit 32.

  The display unit 26 and the control unit 124 included in the main unit 14 may also be included in the radiation measurement probe 12.

  Moreover, the radiation measurement probe 12 according to the present embodiment has a waterproof and dustproof function as a whole by having the above-described configuration.

DESCRIPTION OF SYMBOLS 10 Radiation measuring apparatus, 12 Radiation measurement probe, 14 Main body unit, 16 Front outer case, 18 Rear outer case, 32 Detection unit, 34 Signal processing unit, 36 Front inner case, 38 Rear inner case, 44 Skeletal structure 46 Case part 48 Frame part 51 102 116 Thread groove 62 Radiation detector 64 Photo detector 72 Double-sided adhesive sheet 74 Reflective material 76 Elastic holder 78 Rotary member 80 Transmission member 86 Shock absorbing plate, 88 bleeder substrate, 92, 114 connector, 98 cap, 104 scintillator member, 106 container, 108 peripheral edge, 115 tip wall, 120 arithmetic unit, 122 high pressure generator, 126 MCA unit, 128 CPU-HV unit, 130 Hybrid IC, 132 Temperature Sensor, 138 HV Control Unit, 140 MP, 142 ADC, 144 MCA, 150 CPU, 152 HV circuit.

Claims (8)

A radiation detector having front and rear surfaces spaced apart in the direction of the central axis of the probe and converting radiation into light;
A photodetector having a front surface opposed to a rear surface of the radiation detector and detecting the light and outputting a detection signal;
A container as a hollow member containing at least the radiation detector, the container having a tip wall facing the front surface of the radiation detector;
The portion of the container has a portion extending through the periphery of the photodetector, and exerts a pressing force against the rear surface of the radiation detector to the front, thereby acting the tip wall and the pressing force transmitting portion. A pressing member that allows the radiation detector to be sandwiched between ends;
A radiation measurement probe comprising: The radiation measurement probe according to claim 1,
The pressing member is
A force generating member that is screwed into the container and generates the pressing force by its own rotational movement;
A transmission member provided between the force generation member and the rear surface of the radiation detector so as to be able to slip with respect to the force generation member, and transmitting the pressing force generated by the force generation member to the rear surface of the radiation detector. When,
including,
A radiation measurement probe characterized by that. The radiation measurement probe according to claim 2,
The size of the rear surface of the radiation detection surface is larger than the size of the front surface of the light detection surface,
An annular gap exists around the photodetector in the container,
The transmission member has a cylindrical portion extending in the annular gap;
A radiation measurement probe characterized by that. The radiation measurement probe according to claim 3,
A distal end surface of the working end portion which is a distal end portion of the cylindrical portion abuts on a peripheral edge portion in a rear surface of the radiation detector;
A radiation measurement probe characterized by that. The radiation measurement probe according to claim 4,
The rear surface of the radiation detector and the front surface of the photodetector are bonded, and thereby the photodetector is fixed to the radiation detector.
A radiation measurement probe characterized by that. The radiation measurement probe according to claim 5,
An annular elastic holder disposed in the cylindrical portion and elastically holding the light receiving end of the light detector fixed to the radiation detector while wrapping;
A radiation measurement probe characterized by that. The radiation measurement probe according to claim 6,
The elastic holder suppresses movement of the light receiving end in a direction orthogonal to the probe central axis direction;
A radiation measurement probe characterized by that. The radiation measurement probe according to claim 7,
The elastic holder has a front surface corresponding to a rear surface of the radiation detector and a rear surface opposite to the front surface;
Concavities and convexities are formed on the inner periphery and rear surface of the elastic holder,
A radiation measurement probe characterized by that.

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