Patent Number: 
Section: claims

1. An optical element for diffracting x-rays, comprising: a substrate;  a diffraction structure applied to said substrate, said diffraction structure comprising an exterior surface facing away from said substrate and said diffraction structure capable of diffracting x-rays; and  a protective layer applied to said exterior surface, wherein said protective layer has a structure that substantially absorbs x-rays. 2. The optical element of  claim 1 , wherein said protective layer comprises a stable material. claim 1 3. The optical element of  claim 1 , wherein said stable material is selected from the group consisting of silicon, carbon, B 4 C, Be, Li, B, Al and Sc. claim 1 4. The optical element of  claim 1 , wherein said protective layer comprises a multilayer structure. claim 1 5. The optical element of  claim 4 , wherein said multilayer structure comprises a layer set, wherein said layer set comprises a first layer and a second layer made of a material different than said first layer. claim 4 6. The optical element of  claim 5 , wherein said first layer is adjacent to said second layer. claim 5 7. The optical element of  claim 5 , wherein said first layer comprises a first material with a relatively low atomic number, and said second layer comprises a second material, different than said first material, with a relatively low atomic number. claim 5 8. The optical element of  claim 7 , wherein said first material is selected from the group consisting of silicon, carbon, B 4 C, Be, Li, B, Al and Sc. claim 7 9. The optical element of  claim 8 , wherein said second material is selected from the group consisting of silicon, carbon, B 4 C, Be, Li, B, Al and Sc. claim 8 10. The optical element of  claim 1 , wherein said diffraction structure comprises a layer set, wherein said layer set comprises a first layer and a second layer made of a material different than said first layer. claim 1 11. The optical element of  claim 10 , wherein said protective layer comprises a multilayer structure comprising a second layer set, wherein said second layer set comprises a third layer and a fourth layer made of a material different than said third layer. claim 10 12. The optical element of  claim 10 , wherein said first layer comprises a first material with relatively high atomic number, and said second layer comprises a second material with a relatively low atomic number. claim 10 13. The optical element of  claim 12 , wherein said first material is selected from the group consisting of W, Ni, Mo, Fe, Cr, Co, V, Mn, Nb, Ru, Rh, Pd, La, Ta, Re and Pt. claim 12 14. The optical element of  claim 13 , wherein said second material is selected from the group consisting of silicon, carbon, B 4 C, Be, Li, B, Al and Sc. claim 13 15. The optical element of  claim 12 , wherein said second material is selected from the group consisting of silicon, carbon, B 4 C, Be, Li, B, Al and Sc. claim 12 16. The optical element of  claim 12 , wherein said first layer is adjacent to said second layer. claim 12 17. The optical element of  claim 16 , wherein said first material is selected from the group consisting of W, Ni, Mo, Fe, Cr, Co, V, Mn, Nb, Ru, Rh, Pd, La, Ta, Re and Pt. claim 16 18. The optical element of  claim 17 , wherein said second material is selected from the group consisting of silicon, carbon, B 4 C, Be, Li, B, Al and Sc. claim 17 19. The optical element of  claim 16 , wherein said second material is selected from the group consisting of silicon, carbon, B 4 C, Be, Li, B, Al and Sc. claim 16 20. The optical element of  claim 10 , wherein said first layer and said second layer are uniform. claim 10 21. The optical element of  claim 20 , wherein said first and said second layers have a substantially identical thickness. claim 20 22. The optical element of  claim 21 , wherein said first layer has a thickness having a value ranging from approximately 0.5 nm to approximately 50 nm. claim 21 23. An x-ray system, comprising: an x-ray source emitting a set of x-rays;  an optical element, comprising:  a substrate;  a diffraction structure applied to said substrate, said diffraction structure comprising an exterior surface facing away from said substrate and said diffraction structure diffracting said set of x-rays; and  a protective layer applied to said exterior surface, wherein said protective layer has a structure that substantially absorbs said set of x-rays. 24. The x-ray system of  claim 23 , wherein said protective layer comprises a stable material. claim 23 25. The x-ray system of  claim 24 , wherein said stable material is selected from the group consisting of silicon, carbon, B 4 C, Be, Li, B, Al and Sc. claim 24 26. The x-ray system of  claim 23 , wherein said protective layer comprises a multilayer structure. claim 23 27. The x-ray system of  claim 26 , wherein said multilayer structure comprises a layer set, wherein said layer set comprises a first layer and a second layer made of a material different than said first layer. claim 26 28. The x-ray system of  claim 27 , wherein said first layer is adjacent to said second layer. claim 27 29. The x-ray system of  claim 27 , wherein said first layer comprises a first material with a relatively low atomic number, and said second layer comprises a second material, different than said first material, with a relatively low atomic number. claim 27 30. The x-ray system of  claim 29 , wherein said first material is selected from the group consisting of silicon, carbon, B 4 C, Be, Li, B, Al and Sc. claim 29 31. The x-ray system of  claim 30 , wherein said second material is selected from the group consisting of silicon, carbon, B 4 C, Be, Li, B, Al and Sc. claim 30 32. The x-ray system of  claim 23 , wherein said diffraction structure comprises a layer set, wherein said layer set comprises a first layer and a second layer made of a material different than said first layer. claim 23 33. The x-ray system of  claim 32 , wherein said protective layer comprises a multilayer structure comprising a second layer set, wherein said second layer set comprises a third layer and a fourth layer made of a material different than said third layer. claim 32 34. The x-ray system of  claim 32 , wherein said first layer comprises a first material with relatively high atomic number, and said second layer comprises a second material with a relatively low atomic number. claim 32 35. The x-ray system of  claim 34 , wherein said first material is selected from the group consisting of W, Ni, Mo, Fe, Cr, Co, V, Mn, Nb, Ru, Rh, Pd, La, Ta, Re and Pt. claim 34 36. The x-ray system of  claim 35 , wherein said second material is selected from the group consisting of silicon, carbon, B 4 C, Be, Li, B, Al and Sc. claim 35 37. The x-ray system of  claim 34 , wherein said second material is selected from the group consisting of silicon, carbon, B 4 C, Be, Li, B, Al and Sc. claim 34 38. The x-ray system of  claim 34 , wherein said first layer is adjacent to said second layer. claim 34 39. The x-ray system of  claim 38 , wherein said first material is selected from the group consisting of W, Ni, Mo, Fe, Cr, Co, V, Mn, Nb, Ru, Rh, Pd, La, Ta, Re and Pt. claim 38 40. The x-ray system of  claim 39 , wherein said second material is selected from the group consisting of silicon, carbon, B 4 C, Be, Li, B, Al and Sc. claim 39 41. The x-ray system of  claim 38 , wherein said second material is selected from the group consisting of silicon, carbon, B 4 C, Be, Li, B, Al and Sc. claim 38 42. The x-ray system of  claim 32 , wherein said first layer and said second layer are uniform. claim 32 43. The x-ray system of  claim 42 , wherein said first and said second layers have a substantially identical thickness. claim 42 44. The x-ray system of  claim 43 , wherein said first layer has a thickness having a value ranging from approximately 0.5 nm to approximately 50 nm. claim 43 45. The x-ray system of  claim 23 , wherein said set of x-rays are hard x-rays. claim 23