Method for detecting a mass density image of an object
A method for detecting a mass density image of an object. An x-ray beam is transmitted through the object and a transmitted beam is emitted from the object. The transmitted beam is directed at an angle of incidence upon a crystal analyzer. A diffracted beam is emitted from the crystal analyzer onto a detector and digitized. A first image of the object is detected from the diffracted beam emitted from the crystal analyzer when positioned at a first angular position. A second image of the object is detected from the diffracted beam emitted from the crystal analyzer when positioned at a second angular position. The first image and the second image are combined mathematically to derive a mass density image of the object.
1. A method for detecting an image of an object, comprising:
transmitting an x-ray beam through the object and emitting from the object a transmitted beam;
directing the transmitted beam at an angle of incidence upon a crystal analyzer;
detecting a first image of the object from a first diffracted beam emitted from the crystal analyzer positioned at a first angular position;
detecting a second image of the object from a second diffracted beam emitted from the crystal analyzer positioned at a second angular position;
combining the first image and the second image to derive a refraction image; and
deriving a mass density image of the object from the refraction image.
2. The method of claim 1 , further comprising:
detecting the first image of the object from the first diffracted beam emitted from the crystal analyzer at a low rocking curve angle setting of the crystal analyzer, and
detecting the second image of the object from the second diffracted beam emitted from the crystal analyzer at a high rocking curve angle setting of the crystal analyzer.
3. The method of claim 1 , wherein the first image and the second image are exposed on a detector capable of producing a digitized image.
4. The method of claim 3 , wherein the exposed first image and the exposed second image are digitized.
5. The method of claim 4 , wherein the digitized images are mathematically combined to form a digitized refraction image.
6. The method of claim 5 , wherein the refraction image and the mass density image are defined on a pixel-by-pixel basis.
7. The method of claim 1 , wherein the crystal analyzer is one of a Laue crystal analyzer and a Bragg crystal analyzer.
8. The method of claim 1 , wherein the x-ray beam has an energy level of at least about 16 keV.
9. The method of claim 1 , wherein the x-ray beam has an energy level of at least about 40 kev.
10. The method according to claim 1 wherein the x-ray beam has an energy level in a range of approximately 16 keV to approximately 100 keV.
11. In a method according to claim 1 wherein the x-ray beam is diffracted by a monochromator which is matched in orientation and lattice planes to the crystal analyzer.
12. In a method according to claim 1 further comprising increasing a relative intensity of the image of the object by adjusting an angular position of the crystal analyzer.
13. In a method according to claim 12 wherein the angular position of the crystal analyzer is adjusted in steps of approximately 1 microradian increments.
14. The method of claim 1 , wherein the x-ray beam is monochromatic.
15. The method of claim 1 , wherein deriving amass density image of the object from the refraction image comprises using an algorithm including:
(
ρ
2
-
ρ
1
)
t
2
(
x
i
,
z
j
)
=
∑
k
=
o
j
z
p
K
θ
(
x
i
,
z
j
)
.
where ρ 1 is the mass density of the matrix material, ρ 2 is the mass density of the embedded object, t 2 is the thickness of the embedded object, (x i z j ) represents a pixel in the x-z direction, and z p is the pixel size in the z-direction.
16. A method for detecting an image of an object, comprising:
transmitting an x-ray beam through the object and emitting from the object a transmitted beam;
directing the transmitted beam at an angle of incidence upon a crystal analyzer;
detecting a first image of the object from a first diffracted beam emitted from the crystal analyzer positioned at a first angular position;
detecting a second image of the object from a second diffracted beam emitted from the crystal analyzer positioned at a second angular position;
combining the first image and the second image to derive a refraction image; and
converting the refraction image to a mass density image of the object according to an algorithm comprising:
(
ρ
2
-
ρ
1
)
t
2
(
x
i
,
z
j
)
=
∑
k
=
o
j
z
p
K
θ
(
x
i
,
z
j
)
.
where ρ 1 is the mass density of the matrix material, ρ 2 is the mass density of the embedded object, t 2 is the thickness of the embedded object (x i , z j ) represents a pixel in the x-z direction, and z p is the pixel size in the z-direction.
17. The method of claim 16 , further comprising:
detecting the first image of the object from the first diffracted beam emitted from the crystal analyzer at a low rocking curve angle setting of the crystal analyzer; and
detecting the second image of the object from the second diffracted beam emitted from the crystal analyzer at a high rocking curve angle setting of the crystal analyzer.
18. The method of claim 16 , wherein the first image and the second image each comprise a digitized image.
19. The method of claim 18 , wherein the first and second images are mathematically combined to form a digitized refraction image.
20. The method of claim 19 , wherein the refraction image and the mass density image are defined on a pixel-by-pixel basis.