Wavelength-shifting sheet-coupled scintillation detectors
The present specification describes an X-ray detector that includes at least one scintillator screen for absorbing incident X rays and emitting corresponding light rays, a wavelength shifting sheet (WSS) coupled with the at least one scintillator screen for shifting the emitted light rays, at least one wavelength shifting fiber (WSF) coupled with at least one edge of the WSS for collecting the shifted light rays, and a photodetector for detecting the collected light rays.
1. A detector configured to detect X-ray radiation, the detector comprising:
a sheet of material optically coupled with at least one scintillator screen and configured to absorb scintillator light and emit spectrum shifted light rays, wherein the sheet of material comprises at least one channel;
at least one fiber positioned in the at least one channel and optically coupled to the sheet of material, wherein the at least one fiber is configured to receive the spectrum shifted light rays and spectrum shift the received spectrum shifted light rays to generate twice-spectrum-shifted light rays, wherein the sheet of material is adapted to spectrum shift the light rays to a first wavelength range, wherein the at least one fiber is adapted to spectrum shift the spectrum shifted light rays to a second wavelength range, and wherein the first wavelength range is different from the second wavelength range;
a reflective coating patterned on an edge of the sheet of material everywhere except for at least one transparent opening of the at least one channel, and wherein the at least one channel is not covered by the reflective coating, thereby optically isolating a set of pixels in the at least one transparent opening from the remainder of the pixels formed in the detector; and
a photodetector optically coupled to the at least one fiber and configured to receive and detect the twice-spectrum-shifted light rays at the second wavelength range.
2. The detector of claim 1 , further comprising a fiber guide and wherein the at least one fiber is positioned in said fiber guide.
3. The detector of claim 2 , wherein the photodetector is coupled with the at least one fiber via the fiber guide.
4. The detector of claim 1 , wherein the at least one scintillator screen is configured to absorb the X-ray radiation and emit the scintillator light.
5. The detector of claim 4 , wherein the at least one scintillator screen comprises a material having an optical absorption length and wherein a thickness of the at least one scintillator screen is less than the optical absorption length.
6. The detector of claim 4 , further comprising a material inserted between the at least one scintillator screen and the sheet, wherein the material is configured to correct a non-uniformity in detection by the photodetector.
7. The detector of claim 4 wherein the at least one scintillator screen is coupled with the sheet by placing the at least one scintillator screen over a surface of the sheet and wherein the at least one scintillator screen at least partially covers the surface.
8. The detector of claim 4 , wherein the sheet of material comprises a first surface and a second surface and wherein the at least one scintillator screen at least partially covers the first surface.
9. The detector of claim 8 , further comprising a second scintillator screen positioned to at least partially cover the second surface.
10. The detector of claim 8 , wherein the first surface is coplanar to the second surface.
11. The detector of claim 1 , wherein the at least one channel is physically positioned closer to one edge of the sheet of material than an opposing edge of the sheet of material.
12. The detector of claim 1 , wherein the at least one channel is physically positioned closer to a center of the sheet of material than to edges of the sheet of material.
13. The detector of claim 1 , wherein the reflective coating comprises at least one of a diffuse reflector or a specular reflector material.
14. The detector of claim 1 , wherein the photodetector is a photomultiplier tube (PMT).
15. The detector of claim 1 , wherein the photodetector is coupled with the at least one fiber via a fiber cable guide and a fiber collet.
16. The detector of claim 1 , wherein the sheet of material is optically segmented into pixels using a mechanical milling process.
17. The detector of claim 1 , wherein the sheet of material comprises a second channel in addition to the at least one channel and wherein a second fiber in addition to the at least one fiber is positioned in the second channel.
18. The detector of claim 17 , wherein the at least one fiber and the second fiber are spaced from each other by a distance of 5 mm to 20 mm.
19. The detector of claim 1 , wherein the sheet of material comprises optically isolated pixels ranging in size from 2 mm to 5 mm.
20. The detector of claim 1 , wherein light rays from the sheet of material are multiplexed at a transition from the sheet of material to the at least one fiber.
21. The detector of claim 1 having a thickness less than or equal to 6 mm.