Gadolinium halide scintillators

• US 8,153,983 B1
• Filed: 05/25/2007
• Issued: 04/10/2012
• Est. Priority Date: 05/26/2006
• Status: Active Grant

• Current Assignee: Radiation Monitoring Devices, Inc. (Dynasil Corp. of America)
• Original Assignee: Radiation Monitoring Devices, Inc. (Dynasil Corp. of America)
• Inventors: Higgins, William M, Van Loef, Edgar V, Glodo, Jaroslaw, Shah, Kanai S
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): Boosalis, Faye
• Application Number:
  US11/754,208
• Time in Patent Office: 1,782 Days
• Field of Search: 250/205, 250/361.R, 250/362, 250/367, 250/368, 250/363.03, 252/301.4 F, 252/301.4 H, 252/301.4 R
• US Class Current: 250/362
• CPC Class Codes: G01T 1/202 the detector being a crystal

Abstract

The present invention concerns scintillator compositions comprising gadolinium halide and a dopant. The gadolinium halide and dopant material (e.g., GdI₃:Ce) has surprisingly good characteristics including high light output, high gamma-ray stopping efficiency, fast response, low cost, good proportionality, and minimal afterglow, thereby making the material useful for various applications including, for example, gamma-ray spectroscopy, medical imaging, nuclear and high energy physics research, diffraction, non-destructive testing, nuclear treaty verification and safeguards, and geological exploration. The timing resolution of the scintillators of the present invention also provides compositions suitable for use in imaging applications, such as positron emission tomography (e.g., time-of-flight PET) and CT imaging.

Claims

1. A scintillator comprising a gadolinium halide and a dopant, the gadolinium halide forming a lattice structure in the scintillator having the formula:

Gd(halide)₃.

2. The scintillator of claim 1, wherein the scintillator is a fast scintillator.

3. The scintillator of claim 2, wherein the scintillator comprises a decay-time constant of less than about 50 nanoseconds (ns).

4. The scintillator of claim 2, wherein the scintillator comprises a decay-time constant of less than about 40 ns.

5. The scintillator of claim 2, wherein the scintillator comprises an initial photon intensity of greater than about 1000 Photons/ns×

MeV.

6. The scintillator of claim 1, wherein the scintillator comprises a light output of greater than about 20,000 Photons/MeV.

7. The scintillator of claim 1, wherein the scintillator comprises a light output of greater than about 30,000 Photons/MeV.

8. The scintillator of claim 1, wherein the scintillator comprises sensitivity to both energetic photons and to neutrons.

9. The scintillator of claim 1, wherein the halide is iodide or bromide.

10. The scintillator of claim 7, wherein the dopant comprises Ce, Lu, La, Eu, Pr, Sm Sr, Tl, Cl, F, or I.

11. The scintillator of claim 10, wherein the dopant comprises a mixture of at least two dopants.

12. The scintillator of claim 9, wherein said dopant is present at about 0.1% or more and less than or equal to about 100% by molar weight.

13. The scintillator of claim 9, wherein said dopant is present in an amount of from about 0.1% to about 5.0% by molar weight.

14. The scintillator of claim 9, wherein said dopant is present in an amount of from about 5.0% to about 20% by molar weight.

15. The scintillator of claim 1, wherein said dopant is Ce and present in an amount of about 5.0% by molar weight.

16. The scintillator of claim 15, wherein the scintillator comprises a crystal composition.

17. A radiation detection device, comprising a detector assembly comprising a scintillator comprising a gadolinium halide and a dopant;

and a light photon detection assembly, the gadolinium halide forming a lattice structure in the scintillator having the formula;

Gd(halide)₃.

18. The device of claim 17, wherein the halide is iodide or bromide.

19. The device of claim 18, wherein the dopant comprises Ce, Lu, La, Eu, Pr, Sm, Sr, Tl, Cl, F, or I.

20. The device of claim 17, wherein the device is a positron emission tomography (PET) imaging device.

21. The device of claim 17, wherein the device is an X-ray computed tomography (CT) imaging device.

22. The device of claim 17, wherein the device is a well-logging device.

23. The device of claim 17, wherein the device is a fissionable material detection device.

24. The device of claim 17, wherein said dopant is Ce and present in an amount of about 5.0% by molar weight.

25. The device of claim 24, wherein the scintillator comprises a crystal composition.

26. The device of claim 17, further comprising a data analysis system.

27. The device of claim 17, wherein the light photon detection assembly comprises a photomultiplier tube, a photo diode, a PIN detector, or an avalanche detector.

28. An X-ray and neutron detector assembly, comprising:

a scintillator composition comprising a gadolinium halide and a dopant, the gadolinium halide forming a lattice structure in the scintillator having the formula;

Gd(halide)₃;

a light photon detection assembly; and

a data analysis system.

29. The assembly of claim 28, wherein the halide is iodide or bromide.

30. The assembly of claim 28, wherein the dopant comprises Ce, Lu, La, Eu, Pr, Sm, Sr, Tl, Cl, F, or I.

31. The assembly of claim 29, wherein said dopant is present at about 0.1% or more and less than or equal to about 100% by molar weight.

32. The assembly of claim 28, wherein said dopant is Ce and present in an amount of about 5.0% by molar weight.

33. The assembly of claim 28, wherein the light photon detection assembly comprises a photomultiplier tube, a photo diode, a PIN detector, or an avalanche detector.

34. The assembly of claim 28, wherein the light photon detection assembly comprises a position-sensitive photomultiplier tube, a photo diode, a PIN detector, or an avalanche detector.

35. The assembly of claim 28, wherein the scintillator is coated with a reflective layer, a moisture resistant layer, or a vapor barrier.

36. A method of performing radiation detection, comprising:

providing a detection device comprising a detector assembly comprising a scintillator comprising a gadolinium halide and a dopant, and a light photon detection assembly, wherein the gadolinium halide forms a lattice structure in the scintillator having the formula;

Gd(halide)₃; and

positioning a target within a field of view of the scintillator as to detect emissions from the target.

37. The method of claim 36, wherein the emissions comprise gamma-ray emissions.

38. The method of claim 36, wherein the emissions comprise X-ray emissions.

39. The method of claim 36, wherein the emissions comprise neutron emissions.