Scintillator composition, article, and associated method

• US 20080011953A1
• Filed: 07/11/2006
• Published: 01/17/2008
• Est. Priority Date: 07/11/2006
• Status: Abandoned Application

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Srivastava, Alok Mani, Comanzo, Holly Ann, Venkataramani, Venkat Subramaniam
• Application Number:
  US11/484,080
• Publication Number:
  US 20080011953A1
• Time in Patent Office: Days
• US Class Current: 250/361R
• CPC Class Codes: G01T 1/202 the detector being a crystal

Abstract

A scintillator composition is provided. The scintillator composition may include a matrix having at least one lanthanide ion and at least one halide ion, and a dopant. The dopant may include a trivalent cerium activator ion disposed in the matrix, and a trivalent bismuth activator ion disposed in the matrix.

Claims

1. A scintillator composition, comprising:

a matrix having at least one lanthanide ion and at least one halide ion; and

a dopant, comprising;

a trivalent cerium activator ion disposed in the matrix; and

a trivalent bismuth activator ion disposed in the matrix.

2. The scintillator composition as defined in claim 1, wherein the lanthanide ion comprises lutetium.

3. The scintillator composition as defined in claim 2, wherein the lanthanide ion further comprises scandium, yttrium, gadolinium, lanthanum, praseodymium, terbium, europium, erbium, ytterbium, or combinations of two or more thereof.

4. The scintillator composition as defined in claim 1, wherein the scintillator composition is a single crystal.

5. The scintillator composition as defined in claim 3, wherein the portion of lutetium is in a range of from about 80 mole percent to about 100 mole percent.

6. The scintillator composition as defined in claim 1, wherein the halide ion comprises iodine.

7. The scintillator composition as defined in claim 6, wherein the halide ion further comprises fluorine, chlorine, bromine, or combinations of two or more thereof.

8. The scintillator composition as defined in claim 7, wherein the portion of iodine is in a range of from about 95 mole percent to about 100 mole percent.

9. The scintillator composition as defined in claim 1, wherein the dopant is present in an amount in a range of from about 0.1 percent to about 10 percent a mole percent.

10. The scintillator composition as defined in claim 1, wherein the trivalent cerium activator is present in the dopant in a range of from about 0.1 percent to about 10 percent to the total percent of the dopant.

11. The scintillator composition as defined in claim 1, wherein the trivalent bismuth activator is present in the dopant in an amount in a range of from about 0.1 percent to about 10 percent based on the total percent of the dopant.

12. The scintillator composition as defined in claim 1, wherein the scintillator composition is mono-crystalline.

13. The scintillator composition as defined in claim 12, wherein a crystal size of the mono-crystalline scintillator composition is in a range of from about 1 centimeter×

1 centimeter to about 10 centimeters×

10 centimeters.

14. The scintillator composition as defined in claim 1, wherein the scintillator composition is poly-crystalline.

15. The scintillator composition as defined in claim 14, wherein a crystallite size of the poly-crystalline scintillator composition is in a range of from about 1 micrometer to about 20 micrometers.

16. The scintillator composition as defined in claim 1, wherein the scintillator composition is a wafer.

17. The scintillator composition as defined in claim 1, wherein an attenuation length of the scintillator composition is about 1.7 centimeters for a 511 KeV photon.

18. The scintillator composition as defined in claim 1, wherein a light output of the scintillator composition is in a range of from about 50000 photons per milli electron volt to about 100000 photons per milli electron volt.

19. The scintillator composition as defined in claim 1, wherein a decay time of the scintillator composition is in a range of from about 25 nanoseconds to about 50 nanoseconds.

20. The scintillator composition as defined in claim 1, wherein a rise time of the scintillator composition is in a range of from about 10⁻

11 seconds to about 10<sup>−

8</sup> seconds.

21. The scintillator composition as defined in claim 1, wherein the lanthanide ion consists essentially of lutetium.

22. The scintillator composition as defined in claim 1, wherein an energy resolution of the scintillator composition is less than about 5 percent.

23. A wafer comprising the scintillator composition as defined in claim 1.

24. The wafer as defined in claim 23, having an average thickness in a range of from about 0.5 centimeters to about 3 centimeters.

25. An article comprising the wafer as defined in claim 23 that is configured to detect radiation if present, and to generate an electronic or optical signal in response to detected radiation.

26. The article as defined in claim 25, wherein the article further comprises a photon detector in optical communication with the wafer.

42. A method, comprising exposing the scintillator composition as defined in claim 1 to a radiation source.

44. The scintillator composition as defined in claim 42, wherein the lanthanide halide comprises lutetium iodide.

45. The scintillator composition as defined in claim 42, wherein a solid solubility of the trivalent bismuth activator ion in the matrix having a solid solution of the lanthanide halide is in a range of from about 1 mole percent to about 20 mole percent.

27. A radiation detector for detecting high-energy radiation, comprising:

a scintillation element having a scintillator composition, the scintillator composition comprising;

a matrix comprising a lanthanide halide, wherein the lanthanide halide comprises at least one lanthanide ion and at least one halide ion;

a dopant comprising a trivalent cerium activator ion disposed in the matrix, and a trivalent bismuth activator ion disposed in the matrix; and

a photon detector optically coupled to the scintillation element and capable of converting photons into electrical signals.

28. The radiation detector as defined in claim 27, wherein the radiation detector is configured for use as a nuclear imaging detector.

29. The radiation detector as defined in claim 27, wherein the radiation detector is configured for use as a positron emission tomography detector.

30. The radiation detector as defined in claim 27, wherein the radiation detector is configured for use as a time-of-flight detector.

31. The radiation detector as defined in claim 27, further comprising a digital imaging device operable to receive the electrical signals.

32. The radiation detector as defined in claim 27, wherein the radiation detector is capable of use as a well-logging tool.

33. The radiation detector as defined in claim 32, further comprising:

a housing capable of accommodating the radiation detector, wherein the housing comprises a transmission window; and

a motor for translating the radiation detector such that the transmission window moves with the radiation detector.

34. The radiation detector as defined in claim 27, wherein the photon detector is a photomultiplier tube, a photodiode, a charge-coupled device (CCD) sensor, or an image intensifier.

35. The radiation detector as defined in claim 27, wherein the radiation detector is in operative association with a screen scintillator.

36. The radiation detector as defined in claim 27, further comprising a portable housing and an energy storage device, which together are sized, weighted, and configured so that the radiation detector is portable by a single person.

38. The method as defined in claim 36, wherein the lanthanide ion precursor and the halide ion precursor comprise a mixture of lutetium chloride and lutetium bromide;

and the trivalent cerium activator ion precursor comprises a cerium halide compound and wherein the trivalent bismuth activator ion precursor comprises a bismuth halide compound.

39. The method as defined in claim 36, wherein contacting comprises grinding or ball milling.

40. The method as defined in claim 36, wherein heating is to a temperature in a range of from about 600 degrees Celsius to about 1050 degrees Celsius.

41. The method as defined in claim 36, wherein forming the crystalline scintillator composition comprises at least one of a Bridgman-Stockbarger method;

a Czochralski method, a zone-melting method, a floating zone method, or a temperature gradient method.

37. A method of manufacturing a scintillator composition, comprising:

contacting at least one lanthanide ion precursor and at least one halide ion precursor, a trivalent cerium activator ion precursor, and a trivalent bismuth activator ion precursor to form a mixture having a ratio;

heating the mixture to a temperature to form a molten composition; and

forming a crystalline scintillator composition from the molten composition.

43. A scintillator composition comprising a reaction product of:

a matrix forming material;

a lanthanide halide precursor; and

a dopant comprising a trivalent cerium activator ion precursor and a trivalent bismuth activator ion precursor.