Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
  • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
  • G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
  • G01N23/046—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material using tomography, e.g. computed tomography [CT]
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2223/00—Investigating materials by wave or particle radiation
  • G01N2223/40—Imaging
  • G01N2223/419—Imaging computed tomograph

Definitions

• the present invention relates to an X-ray imaging apparatus .
• the contrast of an X-ray transmission image is caused by the differences in transmittance among X-rays transmitted through parts of an object.
• the transmittance of X-ray depends on the chemical composition of objects, the density of the objects, and the energies of the X-rays (i.e. the wavelength of the X-rays) that are used. Accordingly, in the case of using an X-ray apparatuses in related art, it is difficult to take legible high-contrast images of objects, such as soft materials or biological objects, mainly
• NPL 1 differences among X-rays are proposed (for example, refer to NPL 1) in order to measure high-contrast images of such objects.
• the phase difference appears as refraction in a portion having a density difference, for example, on an interface of a substance.
• an object is irradiated by highly monochromatic X-rays and the intensity of the X-rays transmitted through the object is detected with an X-ray wedge-shaped attenuator.
• the change in the amount of refraction angle of the X-rays through the object is detected as the change in the detected intensity to detect the phase difference in the method described in NPL 1. Since phase information on the X-rays (the amount of refraction of the X-rays) can be detected with the method described in NPL 1, it is possible to measure an image of high contrast ' .
• NPL 1 Yasushi KAGOSHIMA, "Scanning Differential- Phase-Contrast Hard X-Ray Microscopy with Wedge Absorber Detector", Japanese Jounal of Applied Physics, Vol. 43, No. 11A, 2004, pp. L1449-L1451
• the detected intensity of the X-rays is varied depending on absorption and refraction of the X-rays through the object unless the absorption of the X-rays through the object is negligibly small. Accordingly, it is necessary to extract the contribution in detected intensities due to the
• the present invention provides an X-ray imaging apparatus capable of easily adjusting the sensitivity or an X-ray imaging apparatus capable of easily extracting the amount of refraction of X-rays.
• an X-ray imaging apparatus measures an X-ray transmittance image of the object by irradiating an X-ray beam from an X- ray source generating X-rays of a first energy and of a second energy different from the first energy to the object.
• This apparatus includes an attenuator configured to
• the attenuator is configured so as to vary an amount of attenuation of the X- rays depending on a position on which the X-ray beam is incident.
• the detector is configured so as to detect the X- rays of the first energy and of the second energy.
• the X-ray source generating the X-rays of the first energy and of the second energy includes an X-ray source generating X-rays of other energies, in addition to the X-rays of the first energy and of the second energy.
• the detector detecting the X-rays of the first energy and of the second energy includes a detector
• FIG. 1 schematically illustrates an X-ray imaging apparatus according to an embodiment of the present
• FIG. 2A schematically illustrates an X-ray
• FIG. 2B shows an example of the transmittance of the X-ray attenuator in Fig. 2A.
• Fig. 3A schematically illustrates an X-ray attenuator according to a first embodiment of the present invention .
• Fig. 3B shows an example of the transmittance of the X-ray attenuator in Fig. 3A.
• FIG. 4 schematically illustrates an X-ray
• Fig. 5A shows a result of detection by an X-ray detector according to the second embodiment of the present invention .
• Fig. 5B is a graph representing the PF according to the second embodiment of the present invention.
• Fig. 5C is a graph representing the PFs according to the second embodiment of the present invention.
• FIG. 6 is a flowchart showing an X-ray imaging method according to a fourth embodiment of the present invention .
• FIG. 7 is a flowchart showing an X-ray imaging method according to a fifth embodiment of the present invention .
• Fig. 1 schematically illustrates the X-ray imaging apparatus of the present embodiment.
• an object to be measured is irradiated with X- rays generated from an X-ray source to measure an image of the object.
• the X-ray imaging apparatus of the present embodiment includes an irradiation unit, a stage (not shown) on which an object to be measured (hereinafter referred to as an object) 103 is placed, an X-ray attenuator 104, an X- ray detector 105, and a computer (control unit).
• the irradiation unit includes an X-ray source 101 and an X-ray source 101 and an object to be measured (hereinafter referred to as an object) 103 is placed, an X-ray attenuator 104, an X- ray detector 105, and a computer (control unit).
• the irradiation unit includes an X-ray source 101 and an X-ray source 101 and an object to be measured (hereinafter referred to as
• the computer includes a computing machine 106 serving as a calculating unit and a display 107 serving as a display unit. Arrows in Fig. 1 represent X-rays.
• the X-ray source 101 is capable of generating X- rays of at least two different energies. (That is, the X- ray source 101 is capable of generating X-rays of a first energy and a second energy.
• the X-ray source 101 may generate X-rays of a third energy or, of a third energy and a fourth energy, in addition to the X-rays of the first and second energies. The difference between the first energy and the second energy is preferably higher than the energy resolution of the X-ray detector 105.
• a synchrotron radiation source having continuous X-ray energy spectrum or an X-ray tube may be used as the X-ray source 101.
• An X-ray tube capable of producing bremsstrahlung X- rays , at least two kinds of characteristic X-rays, or bremsstrahlung X-rays and at least one kind of
• the characteristic X-rays may be used as the X-ray tube.
• the X- rays are electromagnetic waves having wavelength of about 0.01 angstroms to 100 angstroms (10 ⁇ 12 m to 10 "8 m) .
• the X-ray adjuster 102 adjusts the cross-sectional shapes of the X-rays which are generated from the X-ray source 101 and with which the object is irradiated, and is capable of spatially limiting or dividing the X-rays.
• the X-ray adjuster 102 is configured by providing an aperture in a shield plate made of an absorbing material, such as a heavy metal, shielding the X-rays or sufficiently absorbing the X-rays to fulfill the purpose.
• the aperture may have a slit shape or a pin-hole shape. Alternatively, multiple slit-shaped or pin-hole- shaped apertures may be arranged.
• An X-ray beam adjusted by the X-ray adjuster 102 is subjected to absorption and refraction through the object
• the X-ray attenuator 104 is configured so as to vary the amount of attenuation of the X-rays depending on the position of incident X-ray beam. Accordingly, the amount of X-rays transmitted through the X-ray attenuator
• the amount of attenuation of X-rays is varied depending on the positional shift of the optical path of the X-rays caused by the refraction through the object 103.
• the amount of attenuation of X-rays is varied depending on the position of incident X-rays" means in this description that the amount of attenuation of the X- rays (the amount of change in intensity of the X-rays) is varied depending on the position of incident X-rays "at least one direction.”
• the X-ray attenuator 104 will be specifically described below.
• the X-ray detector 105 it is sufficient for the X-ray detector 105 to have sensitivity to the X-rays of the first energy and the second energy.
• the X-ray detector 105 is more preferably capable of detecting the X-ray spectrum distribution of the X-rays and capable of detecting the intensity of X-rays of each energy.
• the calculating unit 106 calculates physical quantities concerning the object 103 from information on the energies and the intensities of the X-rays detected by the X-ray detector 105.
• the display unit 107 appropriately displays the physical quantities calculated by the calculating unit 106.
• An X-ray spectroscope such as a semiconductor detector, capable of detecting the spectrum distribution of X-rays may be used as the X-ray detector 105.
• a silicon drift detector may be used as the semiconductor detector.
• the object 103 is provided on the stage (not shown) serving as a movement mechanism. Even if only one X-ray beam is formed by the X-ray adjuster 102, moving the object 103 on the stage to scan the object 103 with the X-ray beam allows the whole area of the object 103 to be measured.
• the X-ray beam is refracted when the density, shape, or chemical composition of the object 103 is varied on a surface or inner structure of the object 103. Accordingly, the presence of the object 103 causes the optical path of the X-ray beam to be shifted.
• the shit depends on a change in density, shape, or chemical composition of the object, the energies of incident X-rays, and so on.
• I 0 denotes the intensity of an X-ray beam from the X-ray adjuster 102 and the chemical
• composition of the object 103 is constant for simplicity, an intensity Ii of the X-ray beam transmitted through the
• Equation (1)
• Ii(E,d) Io(E) ⁇ exp ⁇ -1 ( E ) /l es ( E , d) ⁇ (1)
• Equation (1) t denotes the optical path length of the X-rays transmitted through the object 103, l es denotes the attenuation length of the X-rays with respect to the object 103, in which the exponent term denotes the
• E denotes the energy of the X-rays
• d denotes the
• ⁇ denotes an amount of
• Equation (2) refraction angle through the object 103 and it is expressed by Equation (2):
• Equation (3) ⁇ denotes the shift from 1 of the refraction index of a material composing the object 103 with respect to the X-rays
• Equation (3) r e denotes a classical electron radius, ⁇ denotes the wavelength of the X-rays, N denotes the number of atoms per unit volume, and f denotes a
• Nf ' is calculated by adding up the numbers N of the various kinds of atoms per unit volume. Since ⁇ has reciprocal relationship with the energy E and N has linear relationship with the density d, the amount of refraction is increased with the decreasing energy E and with the increasing density d.
• FIG. 2A schematically illustrates the X-ray
• a positional shift Ar occurs between an optical path 203 of the X-ray beam refracted through the object 103 and an optical path 202 of the X-ray beam when the object 103 does not exist on the optical path.
• Fig. 2B shows an example of the transmittance of the X-ray attenuator 104 with respect to the positional shift Ar.
• the X-ray attenuator 104 is configured so as to vary the transmittance with the positional shift Ar.
• Equation (6) The amount ⁇ of refraction angle of X-rays through the object 103 is expressed by Equation (6).
• An amount ⁇ of phase shift of X-rays is calculated according to Equation (7).
• the X-ray imaging apparatus of the present embodiment uses the X-ray source generating X-rays of multiple energies and the X-ray detector detecting the X-rays of multiple energies.
• the X-ray detector has an energy resolution sufficient to discriminately detect the intensity of the X-rays of each of multiple energies.
• the amount of refraction of the X-rays transmitted through the object is varied with the energies of the X-rays. Consequently, with the X-ray imaging apparatus of the present embodiment, it is possible to vary the sensitivity of the transmitted X-ray with respect to the positional shift by changing the energy of the X-ray beam used in the calculating unit. [0041] If the absorption through the object 103 is not negligible, the term of the transmittance through the object 103 in Equation (4) is not equal to one. Accordingly, it is not possible to uniquely determine the positional shift Ar from Equation (5) when the monochromatic X-ray is used. In contrast, since the X-ray imaging apparatus of the present embodiment uses the X-rays of multiple energies for
• Equation (5) is given for the X-ray of each energy.
• t(E) is constant regardless of the energy. Accordingly, it is possible to calculate Ar(E), t (corresponding to the thickness of the object), and d by measuring I 2 (E,d) for two or more energies E and using Equation (5).
• the calculation of Ar(E) allows phase information including the amount of refraction and the amount of phase shift to be calculated from Equations (6) and (7).
• the detection sensitivity of the X-ray imaging apparatus can be easily varied in a manner described below. Specifically, the use of 12(E) for a lower energy E in the calculation of the above physical quantities allows
• the X-ray imaging apparatus of the present embodiment it is possible to easily adjust the sensitivity to the positional shift of the optical path of the X-ray beam. In addition, it is possible to easily extract the amount of refraction of the X-rays through the object 103 with the X-ray imaging apparatus of the present embodiment even if the absorption of the X ray through the object 103 is not negligible.
• An element in which above-mentioned attenuators are arranged in a line form or in a two-dimensional array form may be used as the X-ray attenuator used in the present embodiment.
• the element is configured so as to vary the amount of attenuation of the X-rays depending on position of the incident X-ray beam in each attenuator.
• Such an element may be considered as an X-ray attenuator array.
• any X-ray detector having the sensitivity to the X-rays of the first energy and the second energy may be used as the X-ray detector used in the present embodiment. Accordingly, an X-ray detector in which a fluorescent substance converting the X-rays into
• a photo- detector capable of detecting the fluorescence may be used as the X-ray detector.
• a charge coupled device (CCD) image sensor or a complementary metal oxide semiconductor (CMOS) image sensor made of single crystal silicon may be used as the photodetector .
• CMOS complementary metal oxide semiconductor
• a flat panel image sensor, made of thin non-single crystal silicon, may be used as the photodetector.
• the attenuators in the X-ray attenuator array described above may be associated with the pixels in the image sensor in one-to-one, one-to-many, or many-to-one relationship in spatial arrangement.
• a rotating anode X-ray tube made of molybdenum is used as the X-ray source 101 in the first embodiment.
• Two apertures each having spatial size of 50 ⁇ x 50 ⁇ are used as the X-ray adjuster 102.
• the shield plate is made of tantalum. The two apertures are arranged along the optical path, and the cross-sectional size of X-ray beam is limited to a certain value by the X- ray adjuster.
• Fig. 3A shows an example of the cross -sectional shape of an X-ray attenuator 104a in the first embodiment.
• the X-ray attenuator 104a shown in Fig. 3A has a square pillar shape and is made of tantalum. Although tantalum is used as the material of the X-ray attenuator 104a in the first embodiment, another material capable of sufficiently shielding the X-rays may be used. Also in the first
• a positional shift Ay occurs between an optical path 403 of the X-ray beam refracted through the object 103 and an optical path 402 of the X-ray beam when the object 103 does not exist on the optical path.
• the function PF(Ay) has a shape shown by a solid line in Fig. 3B.
• the positional shift ⁇ in the Y-axis direction shown in Fig. 3A can be detected ih an area indicated by a upward curly bracket with ⁇ in which the transmittance is uniquely varied with respect to the positional shift shown by the solid line in Fig. 3B to calculate the physical quantities concerning the object 103 in the manner described above.
• the X-ray attenuator 104a in which the amount of attenuation of the X-rays is varied depending on the
• an X-ray attenuator in which the amount of attenuation of the X-rays is varied depending on the positions in both the Y and the Z directions of the incident X-rays may be used.
• the X-ray attenuator 104a may be rotated around the X axis (the optical axis of the X-ray imaging apparatus) by 90° for additional measurement .
• the use of the result of the detection concerning the X-rays of higher energies, among the results of the detection by the X-ray detector 105, in the calculation in the calculating unit 106 allows the sensitivity to be adjusted to detect the positional shift. This is because the amount of refraction through the object 103 becomes small and the positional shift in the optical path is decreased in the case of the X-rays of higher energies.
• a filter for example, a metal filter or a
• multilayer mirror may be arranged on the optical path of the X-ray imaging apparatus to remove the X-rays in energy ranges that are not used in the calculation in the
• a scattered X-rays removing unit such as an anti-scattering X-ray grid, capable of removing scattered X-rays may be provided in the X-ray imaging apparatus.
• the X-rays of three or more energies may be used in the calculation in the calculating unit 106.
• the calculated physical quantities concerning the object 103 may not be constant due to, for example, the effect of noise included in the value 12(E) detected by the X-ray detector 105.
• a centroid value may be calculated for the collection of the calculated physical quantities to calculate optimal values of the physical quantities .
• an X-ray attenuator 104b having a cross-sectional shape shown in Fig. 4 is used as the X-ray attenuator 104.
• the X-ray attenuator 104b is made of stainless steel having X-ray absorption ability.
• a broken line 602 in Fig. 4 represents the optical path of an X-ray beam when the object 103 does not exist.
• a thin solid line 603 in Fig. 4 represents the optical path of an X-ray beam refracted through the object 103.
• the X-ray beam that is transmitted through the X-ray attenuator 104b on the optical path represented by the thin solid line 603 exhibits an intensity higher than that of the X-ray beam that is transmitted through the X-ray attenuator 104b on the optical path represented by the broken line 602.
• the X-ray beam is refracted on an optical path represented by a bold solid line 605
• lower intensity is detected due to the difference in the optical path length.
• the direction in which the positional shift of the optical path can be detected in the second embodiment is the Y-axis direction in Fig. 4 in which the transmittance is varied with respect to the positional shift.
• I 2 (E,d) Io(E) ⁇ exp ⁇ -t (E ) /l es (E , d) ⁇ ⁇ exp ⁇ -1(E) /l ep (E) ⁇
• Attenuator 104b is denoted by a, as shown in Fig. 4, and the optical path length represented by the broken line 602 of the X-ray beam through the X-ray attenuator 104b is denoted by 1 0 , an optical path length 1(E) is represented by
• Equation ( 9 )
• I 2 (E,d) I 0 (E) ⁇ exp ⁇ -t (E) /l es (E,d) ⁇ ⁇ exp [-tan(a) ⁇ ⁇ locot(a) -Ay ( E ) ⁇ /l e p ( E ) ] (10)
• the optical path length 1 0 is calculated according to Equation (11) because the optical path length 1 0 depends on the apparatus alignment and is measured in a state in which the object 103 does not exist:
• the X-ray beam from the X-ray adjuster 102 has intensity distribution and angle divergence in the cross- sectional direction of the X-ray adjuster 102.
• the detected value I 2 may be affected by, for example, machining error of the X-ray attenuator.
• the function PF may be corrected in consideration of the effects of the above factors. Alternatively, the function PF(Ay) may be actually measured in a manner described below.
• Fig. 5A shows the intensity information detected by the X-ray detector 105 when the X-ray attenuator 104b is moved ( translational scanned) in the Y-axis direction in the case that the object 103 does not exist on the optical path of the X-ray imaging apparatus .
• the difference of each line in Fig. 5A depends on the amount of change in position of the X-ray attenuator 104b corresponding to the positional shift Ay in Fig. 4.
• the change of the intensity information concerning certain energy E with respect to the positional shift Ay can be measured to calculate the function PF(Ay) .
• the detected intensities of the X-rays are low in an energy range A in Fig.
• the S/N ratio of the intensity information may possibly be decreased.
• the function PF(Ay) may be calculated from adding up the interval of a certain energy range in the intensity information with respect to the positional shift Ay.
• the adding result, as explained above, in the energy range A with respect to the positional shift Ay is shown in Fig. 5B as measured values (solid line).
• the measured values are normalized.
• Calculated values 1 (broken line) in Fig. 5B denotes a transmittance curve with respect to the positional shift Ay when the cross-sectional size of the X-ray beam is much smaller than the positional shift Ay.
• Fig. 5B shows that the measured values (solid line) results from extension of the transmittance curve in the direction of the
• the fitting values for the measured values corresponds to the function PF(Ay) .
• the fitting values for the measured values are shown as calculated values 2 (open circles) in Fig. 5B.
• a fitting function, such as the calculated values 2, capable of satisfactorily representing the measured values may be used as the function PF(Ay) .
• Fig. 5C shows the adding results of the energy range A, as same as in Fig. 5B, and of the other energy ranges B to D in Fig. 5A with respect to the positional shift Ay.
• the change in each intensity curve shown in Fig. 5C corresponds to the function PF(Ay) in each energy range.
• I 2 (E,d) Io(E) ⁇ exp ⁇ -1 ( E ) /l es (E,d) ⁇ PF(E, Ay) (12)
• Ay PF "1 (E, I 2 (E,d) / ⁇ I 0 ⁇ exp ( -1 ( E ) /l es ( E , d) ) ⁇ ) (13)
• the X-ray attenuator 104b of the second embodiment can expand the range of the sensitivity to the positional shift of the optical path, compared to the X-ray attenuator 104a of the first embodiment.
• the adding calculation may not be performed.
• the intensity information detected in the X-ray detector 105 exhibits a good S/N ratio
• the adding calculation can be performed in the above manner to improve the S/N ratio even if the intensity of the X-rays generated in the X-ray source 101 is low.
• the energy range in which the adding calculation is performed is preferably set to the range in which the difference in the maximum value of the amount of refraction through the object 103 between the energies at both ends of the range does not exceed the divergence angle of the X-ray beam adjusted by the X-ray adjuster 102.
• the interval is set to the above range in order to decrease the affect of aberration caused by the width of the energies on the image quality.
• the attenuation length through the object 103 and the X-ray attenuator 104b is not constant, unlike the case of using monochromatic X-rays. Accordingly, the attenuation length that is corrected in accordance with the energy range in which the adding calculation is performed and the optical path length may preferably be used. However, when the length of the optical path through the object 103 and the X- ray attenuator 104b is short, the attenuation length may be used as a constant value. Particularly, if the ratio of the amount of change in the attenuation length through the object 103 with respect to the median of the attenuation length is smaller than the noise ratio of the intensity information detected by the X-ray detector 105, the
• Attenuation length may be used as a constant value.
• the element whose shape (thickness) is varied with the incident position of the X-rays is used as the X-ray attenuator in the second embodiment.
• a device in which the transmittance of the X-rays is varied with the incident position of the X-rays may be used as the X-ray attenuator.
• a device in which the density distribution or the chemical composition distribution is varied with the incident position of the X-rays may be used as the X-ray attenuator.
• the X-ray attenuator may be composed of two metals differing in the absorption ability of the X-rays and the composition of the two metals may be varied with the incident position of the X-rays.
• the size or density of the pores may be varied with the incident position of the X-rays.
• An X-ray imaging apparatus differs from the X-ray imaging apparatus of the first embodiment in the X-ray adjuster 102, the X-ray attenuator 104, and the X-ray detector 105.
• an aperture in which multiple pin holes (having a diameter of 60 ⁇ ) are two- dimensionally arranged in a shield plate made of tantalum is used as the X-ray adjuster 102.
• X-ray attenuators as in the first embodiment or the second embodiment that are two- dimensionally arranged are used as the X-ray attenuator 104.
• Multiple X-ray detectors that are capable of detecting the spectrum distribution of X-rays and that are two- dimensionally arranged are used as the X-ray detector 105.
• the X-rays from the X-ray source 101 are divided into multiple X-ray beams in the X-ray adjuster 102 and the X-ray beams are incident on the object 103.
• the X-ray beams transmitted and refracted through the object 103 are
• the X-ray imaging apparatus of the third embodiment information on multiple points on the object, corresponding to the number of the X-ray beams divided by the X-ray adjuster 102, can be simultaneously detected by the X-ray detector 105. Accordingly, it is possible for the X-ray imaging apparatus of the third embodiment to measure the object in a shorter time, compared with the X-ray imaging apparatus of the first embodiment or the second embodiment .
• the X-ray attenuator 104 may be integrated with the X-ray detector 105 without spacing.
• FIG. 6 is a flowchart showing the X-ray imaging method according to the fourth embodiment .
• Step 101 the object 103 is prepared and the object 103 is arranged on the stage of the X-ray imaging apparatus.
• the object 103 is irradiated with an X- ray beam from the X-ray adjuster 102 and the X-ray beam transmitted through the object 103 and the X-ray attenuator 104 is detected by the X-ray detector 105 to acquire X-ray spectrum distribution.
• the object 103 is scanned with the X-ray beam by moving the stage of the X-ray imaging apparatus to acquire the X-ray spectrum distribution corresponding to each position of the object 103.
• the X-ray beam may be moved, instead of the stage, to scan the object 103 with the X-ray beam.
• an image of the object is calculated (generated) by the calculating unit 106 on the basis of the intensity information about the X-rays of certain energy, within the X-ray spectrum distribution detected by the X-ray detector 105.
• the image of the object is displayed by the display unit 107 on the basis of the result of the calculation in the calculating unit 106.
• images of the object may be calculated by the calculating unit 106 on the basis of the intensity information about the X-rays of various energies and the images may be displayed in a list by the display unit 107.
• S105 it is determined whether sufficient sensitivity is achieved. If the detection sensitivity is poor and a desired image is not generated, in S106, the energy of the X-rays used in the calculation in the
• calculating unit 106 is changed to another one within the X- ray spectrum distribution acquired in S102.
• an image of the object is calculated (generated) by the
• an image can be generated on the basis of any one of the at least two detection results of the X-rays, detected by the detector, to easily adjust the sensitivity to the positional shift of the optical path of the X-ray beam.
• FIG. 7 is a flowchart showing the X-ray imaging method according to the fifth embodiment.
• the object 103 is prepared and the object 103 is arranged on the stage of the X-ray imaging apparatus.
• the object 103 is
• the object 103 is scanned with the X-ray beam by moving the stage of the X-ray imaging apparatus to acquire the X-ray spectrum distribution corresponding to each position of the object 103.
• the X-ray beam may be moved, instead of the stage, to scan the object 103 with the X-ray beam.
• Physical quantities of the object are calculated by the calculating unit 106 on the basis of the intensity information about the X-rays of two or more certain energies, within the X-ray spectrum distribution detected by the X-ray detector 105. Specifically, in S203, the intensity I 2 of the X-rays of each of the two or more energies is substituted into Equation (5) to acquire two or more equations. In S204, the positional shift Ar , the density d of the object, and the thickness t of the object are calculated from the two or more equations. In S205, the amount ⁇ of refraction angle or the amount ⁇ of phase shift of X-ray is calculated from Equation (6) or Equation (7) by using the positional shift Ar.
• the distributions of the positional shift Ar, the amount ⁇ of refraction angle, and the amount ⁇ of phase shift calculated at each position of the object may be displayed by the display unit 107. According to the X-ray imaging method of the fifth embodiment, it is possible to easily extract the amount of refraction of the X-rays

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