Soller slit using low density materials
A Soller slit device is provided for collimation of high energy radiation, such as X-ray or EUV radiation, and has a low angle of divergence (less than 0.1°) and a high transmission efficiency (60 to 80% or greater). The Soller slit is made up of multiple, parallel blades of low-density material, such as glass, mica, or the like, which can be treated to reduce reflectivity. The Soller slit device of the invention advantageously provides an increased peak intensity and decreased peak width in diffraction patterns produced in high energy diffractometry applications, such as X-ray diffractometry.
1. A device for collimating high energy X-rays comprising:
a plurality of substantially parallel planar blades that are stacked and spaced apart from one another to form a Soller slit having passages for the transmission of X-rays, said blades being constructed from glass sheets each having a thickness less than 250 μm and whose surfaces have a non-reflective treatment to absorb divergent X-rays that are not substantially parallel to said blades.
2. The Soller slit device of claim 1 wherein said device transmits at least 60% of incident high-energy radiation.
3. The Soller slit device of claim 2 , wherein the transmission efficiency is in the range of 60–80%.
4. The Soller slit device of claim 1 , wherein the length of each blade in the direction of transmission is greater than 5 cm.
5. The Soller slit device of claim 4 , wherein the blade length is at least 12cm.
6. The Soller slit device of claim 5 , wherein the blade length is in the range of 12–15 cm.
7. The Soller slit device of claim 1 , wherein the thickness of each blade is no greater than 70 μm.
8. The Soller slit device of claim 7 , wherein the thickness of each blade is approximately 50 μm.
9. The Soller slit device of claim 1 , wherein the surface of each of the blades has a coating that is non-reflective to X-rays.
10. The Soller slit device of claim 9 , wherein the blades each have a coating of barium sulfate.
11. The Soller slit device of claim 1 , wherein the surface of each of the blades is etched to prevent reflection.
12. A system for performing high energy radiation diffractometry, comprising:
a high energy X-ray source;
a high energy radiation collimating device comprising a plurality of substantially parallel planar blades that are stacked and spaced apart from one another to form passages for the transmission of X-rays, said blades being constructed from glass sheets each having a thickness less than 250 μm and whose surfaces have a non-reflective treatment to absorb divergent X-rays from said source that are not substantially parallel to said blades; and
a device for collecting X-ray radiation after the X-ray radiation impinges on a sample to be examined.
13. The diffractometry system of claim 12 , wherein the high energy radiation collimating device forms a Soller slit device.
14. The diffractometry system of claim 12 , wherein the length of each blade in the direction of transmission is greater than 5 cm.
15. The diffractometry system of claim 14 , wherein the blade length is at least 12 cm.
16. The diffractometry system of claim 15 , the blade length is in the range of 12–15 cm.
17. The diffractometry system of claim 12 , wherein the thickness of each blade is no greater than 7μm.
18. The diffractometry system of claim 17 , wherein the thickness of each blade is approximately 50 μm.
19. The diffractometry system of claim 12 , wherein the surface of each of the blades has a coating that is non-reflective to X-rays.
20. The diffractometry system of claim 19 , wherein the blades each have a coating of barium sulfate.
21. The diffractometry system of claim 12 , wherein the surface of each of the blades is etched to prevent reflection.