Patent Number: 
Section: claims

1. An X-ray Talbot capturing apparatus comprising:a plurality of gratings in which slits are formed;a radiation source which irradiates radiation to pass through the plurality of gratings;a radiation detector which captures a moire image; anda holder which holds the gratings,wherein, the holder includes a receiving unit including a receiving surface with a curve and a pressing unit including a pressing surface with a curve;each grating is held between the receiving surface of the receiving unit and the pressing surface of the pressing unit of the holder and bent in an arc shape with a point of the radiation source as a center;an elastic member is positioned between a first surface of the grating and the pressing surface of the pressing unit or a second surface of the grating opposite of the first surface and the receiving surface of the receiving unit; andan opening is provided in each of the receiving unit and the pressing unit of the holder and the elastic member so as not to block radiation irradiated on the grating. 2. The X-ray Talbot capturing apparatus according to claim 1, wherein, the receiving surface of the receiving unit and the pressing surface of the pressing unit of the holder are bent in an arc shape with the point of the radiation source as the center. 3. The X-ray Talbot capturing apparatus according to claim 1, wherein, at least one of the receiving surface of the receiving unit or the pressing surface of the pressing unit of the holder is bent in an arc shape with the point of the radiation source as the center; andthe grating is pressed entirely against the receiving surface or the pressing surface bent in the arc shape by the elastic member. 4. The X-ray Talbot capturing apparatus according to claim 1, wherein, an edge of the elastic member is made so as not to be outside an edge of the receiving surface of the receiving unit of the holder and an edge of the pressing surface of the pressing unit of the holder in contact with the grating. 5. The X-ray Talbot capturing apparatus according to claim 1, wherein, the receiving unit of the holder is connected to the pressing unit with screws in an entire circumference of a periphery with the grating and the elastic member placed in between. 6. The X-ray Talbot capturing apparatus according to claim 1, wherein, the receiving surface of the receiving unit of the holder or the pressing surface of the pressing unit in contact with the grating are processed so as to slide easily. 7. The X-ray Talbot capturing apparatus according to claim 1, wherein, an absolute value of a difference of a thermal expansion coefficient of the receiving unit and the pressing unit of the holder with respect to the thermal expansion coefficient of the grating is equal to or less than 4×10−6. 8. The X-ray Talbot capturing apparatus according to claim 1, wherein, hardness of the elastic member is a durometer hardness equal to or less than A15. 9. The X-ray Talbot capturing apparatus according to claim 1, wherein, the elastic member has a concave unit or a hole formed in a surface in contact with the receiving unit or the pressing unit of the holder. 10. The X-ray Talbot capturing apparatus according to claim 1, wherein, the receiving unit of the holder is formed with material including a thermal expansion coefficient larger than a thermal expansion coefficient of the pressing unit.