X-ray imaging apparatus

Abstract

An X-ray imaging apparatus comprises a grating configured to form an interference pattern by diffracting X-rays from an X-ray source, a amplitude grating configured to partly shield X-rays forming the interference pattern, and an X-ray detector configured to detect an intensity distribution of X-rays from the amplitude grating. The amplitude grating is comprised of a central area and a peripheral area and the peripheral area shows an X-ray transmittance higher than the central area relative to X-rays perpendicularly entering the amplitude grating.

1 . (canceled) 
     
     
         2 . An amplitude grating which shields X-rays, comprising:
 a grating region in which a shielding portion for shielding X-rays and a transmitting portion for transmitting X-rays are arranged,   wherein said shielding portion has a width measured in the direction along which said shielding portion and said transmitting portion are arranged, and   wherein an average value of the width of said shielding portion in a central area of the amplitude grating is larger than an average value of the width of said shielding portion in a peripheral area of the amplitude grating, where said central area of the amplitude grating is a region of said grating region having a distance smaller than a predetermined value from a center of the amplitude grating, while said peripheral area is a region having a distance greater than the predetermined value from said center.   
     
     
         3 . The amplitude grating according to  claim 2 ,
 wherein said shielding portion has a thickness portion measured in a direction perpendicular to the direction along which said shielding portion and the transmitting portion are arranged, and   wherein an average value of the thickness of said shielding portion in said central area of the amplitude grating is greater than an average value of the thickness of said shielding portion in said peripheral area of the amplitude grating.   
     
     
         4 . The amplitude grating according to  claim 2 , wherein said grating region is a curved grating region. 
     
     
         5 . The amplitude grating according to  claim 2 , wherein said grating region is a flat-plate shaped grating region. 
     
     
         6 . The amplitude grating according to  claim 2 , wherein said shielding portion and said transmitting portion are one-dimensionally arranged in said grating region. 
     
     
         7 . The amplitude grating according to  claim 2 , wherein said shielding portion and said transmitting portion are two-dimensionally arranged in said grating region. 
     
     
         8 . The amplitude grating according to  claim 2 , wherein said grating region has a plurality of shielding portions. 
     
     
         9 . An amplitude grating which shields X-ray comprising:
 a grating region in which a shielding portion for shielding X-rays and a transmitting portion for transmitting X-rays are arranged,   wherein said shielding portion has a thickness measured in a direction perpendicular to the direction along which said shielding portion and said transmitting portion are arranged,   wherein an average value of the thickness of said shielding portion in a central area of the amplitude grating is greater than an average value of the thickness of said shielding portion in a peripheral area of the amplitude grating, where said central area of the amplitude grating is a region of said grating region having a distance smaller than a predetermined value from a center of said amplitude grating, while said peripheral area is a region having a distance greater than the predetermined value from said center, and   wherein a structure arranged on said shielding portion in said peripheral area is made of a material showing a high X-ray transmissivity, and the X-ray transmissivity of the material is higher than an X-ray transmissivity of a material constituting said shielding portion.   
     
     
         10 . The amplitude grating according to  claim 9 , wherein said structure is arranged on said shielding portion in said central area, and
 wherein an average value of the thickness of said structure in said peripheral area of the amplitude grating is greater than an average value of the thickness of said structure in said central area.   
     
     
         11 . The amplitude grating according to  claim 9 , wherein said grating region is a curved grating region. 
     
     
         12 . The amplitude grating according to  claim 9 , wherein said grating region is a flat-plate shaped grating region. 
     
     
         13 . The amplitude grating according to  claim 9 , wherein said shielding portion and said transmitting portion are one-dimensionally arranged in said grating region. 
     
     
         14 . The amplitude grating according to  claim 10 , wherein said shielding portion and said transmitting portion are two-dimensionally arranged in said grating region. 
     
     
         15 . The amplitude grating according to  claim 10 , wherein said grating region has a plurality of shielding portions.