Doped cesium barium halide scintillator films

• US 8,957,386 B1
• Filed: 08/01/2012
• Issued: 02/17/2015
• Est. Priority Date: 04/28/2011
• Status: Active Grant

• Current Assignee: Radiation Monitoring Devices, Inc. (Dynasil Corp. of America)
• Original Assignee: Radiation Monitoring Devices, Inc. (Dynasil Corp. of America)
• Inventors: Bhandari, Harish B., Nagarkar, Vivek V.
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): BOOSALIS, FANI POLYZOS
• Application Number:
  US13/564,672
• Time in Patent Office: 930 Days
• Field of Search: 250/362, 250/361.R, 250/370.11, 250/366, 250/367
• US Class Current: 250/362
• CPC Class Codes: C09K 11/7719 Halogenides C09K11/7716 takes precedence
• CPC Class Codes: C09K 11/7733 with alkali or alkaline earth metals
• CPC Class Codes: C23C 14/0694 Halides
• CPC Class Codes: C23C 14/24 Vacuum evaporation
• CPC Class Codes: C23C 14/243 Crucibles for source material C23C14/28, C23C14/30 take precedence
• CPC Class Codes: G01T 1/202 the detector being a crystal
• CPC Class Codes: G01T 1/2023 Selection of materials see provisionally also G01T1/202
• CPC Class Codes: G21K 2004/06 with a phosphor layer

Abstract

Strontium halide scintillators, calcium halide scintillators, cerium halide scintillators, cesium barium halide scintillators, and related devices and methods are provided.

Claims

1. A scintillator comprising, a ternary scintillator compound comprising a dopant and cesium barium halide, wherein the scintillator is in the form of a microcolumnar scintillator film or a noncolumnar polycrystalline film, and wherein the scintillator has the formula CsBa₂I₅:

Eu or CsBa₂I₅;

Eu+Tl.

2. The scintillator of claim 1, wherein the scintillator has a thickness of less than about 20 microns.

3. The scintillator of claim 1, wherein the scintillator has a thickness greater than about 1 cm.

4. The scintillator of claim 1, wherein the scintillator is in the form of an amorphous microcolumnar scintillator film or a crystalline microcolumnar scintillator film.

5. The scintillator of claim 1, wherein the scintillator comprises less than 0.05% afterglow at 2 ms following X-ray excitation.

6. The scintillator of claim 1, wherein the scintillator further comprises a coating layer comprising doped or undoped cesium iodide.

7. A radiation detection device comprising a scintillator of claim 1 and a photodetector assembly optically coupled to the scintillator.

8. The radiation detection device of claim 7, further comprising electronics coupled to the photodetector assembly so as to output image data in response to radiation detected by the scintillator.

9. A method of performing radiation detection, comprising:

providing a detector device comprising a scintillator of claim 1 and a photodetector assembly optically coupled to the scintillator; and

positioning a radiation source within a field of view of the scintillator so as to detect emissions from the radiation source.

10. The scintillator of claim 1, wherein the scintillator has a thickness of less than about 500 microns.

11. The scintillator of claim 1, wherein the scintillator has a thickness of less than about 1 cm.

12. The scintillator of claim 1, wherein the scintillator has a thickness greater than about 3 cm.

13. The scintillator of claim 1, wherein the scintillator has a thickness greater than about 5 cm.

14. A hot wall evaporation method of making a doped cesium barium halide scintillator, the method comprising:

providing an evaporation apparatus comprising an evaporation chamber having a first end portion with a substrate positioned in a holder, a second end portion with at least one source boat, and one or more chamber walls at least partially disposed between the first and second end portions;

positioning a dopant and a source at the second end portion so as to allow evaporation of the dopant and the source into the evaporation apparatus; and

depositing a scintillator film comprising the dopant and the source on a surface of the positioned substrate, the scintillator film comprising doped cesium barium halide having the formula CsBa₂I₅;

Eu or CsBa₂I₅;

Eu+Tl.

15. The method of claim 14, wherein the film is deposited by a process comprising applying heat to the evaporation chamber so as to vaporize the dopant and the source for film deposition while maintaining a temperature relationship of T_wall>

T_source>

T_substrate for at least a portion of the deposition process.

16. The method of claim 14, wherein T_source is between about 300°

C. and about 750°

C.

17. The scintillator of claim 14, wherein the scintillator comprises less than 0.05% afterglow at 2 ms following X-ray excitation.

18. The method of claim 14, wherein the dopant and the source are included in melt-growth polycrystals positioned in one source boat at the second end portion.

19. The method of claim 18, wherein the melt-growth crystal is synthesized from CsI, BaI₂ and EuI₂.

20. A scintillator produced by the method of claim 14.

21. A deposition method of making a doped cesium barium halide scintillator, the method comprising:

providing a deposition apparatus comprising a vacuum chamber having a substrate at a first end and at least one source boat at a second end of the chamber;

positioning a source material and a dopant material in the at least one source boat; and

depositing a scintillator film comprising doped cesium barium halide on the substrate, wherein the doped cesium barium halide has the formula CsBa₂I₅;

Eu or CsBa₂I₅;

Eu+Tl.

22. The method of claim 21, wherein the dopant material and the source material are included in melt growth polycrystals positioned in one source boat at the second end portion.

23. The method of claim 21, wherein the apparatus comprises a first source boat comprising cesium iodide, a second source boat comprising barium iodide, and a third source boat comprising europium iodide.

24. The method of claim 23, wherein the apparatus further comprises a fourth source boat comprising thallium iodide.

25. The method of claim 21, wherein the scintillator has a thickness of less than about 20 microns.

26. The method of claim 21, wherein the scintillator has a thickness greater than about 1 cm.

27. The method of claim 21, wherein the scintillator is in the form of an amorphous microcolumnar scintillator film or a crystalline microcolumnar scintillator film.

28. A scintillator produced by the method of claim 21.

29. The method of claim 21, wherein the scintillator has a thickness of less than about 500 microns.

30. The method of claim 21, wherein the scintillator has a thickness of less than about 1 cm.

31. The method of claim 21, wherein the scintillator has a thickness greater than about 3 cm.

32. The method of claim 21, wherein the scintillator has a thickness greater than about 5 cm.