SCINTILLATOR CRYSTALS, METHOD FOR MAKING SAME, USE THEREOF

• US 20070210256A1
• Filed: 05/14/2007
• Published: 09/13/2007
• Est. Priority Date: 02/17/2000
• Status: Active Grant

• Current Assignee: Stichting Voor de Technische Wetenschappen
• Original Assignee: Stichting Voor de Technische Wetenschappen
• Inventors: Dorenbos, Pieter, Van Loef, Edgar, Van Eijk, Carel, Gudel, Hans-Ulrich, Kramer, Karl
• Granted Patent: US 7,479,637 B2
• Time in Patent Office: Days
• US Class Current: 250/361.R
• CPC Class Codes: C01F 17/253 Halides
• CPC Class Codes: C01F 17/271 Chlorides
• CPC Class Codes: C09K 11/7772 Halogenides C09K11/7767 takes precedence
• CPC Class Codes: G01T 1/2023 Selection of materials see provisionally also G01T1/202

Abstract

The invention concerns an inorganic scintillator material of general composition M1−xCexCl3, wherein: M is selected among lanthanides or lanthanide mixtures, preferably among the elements or mixtures of elements of the group consisting of Y, La, Gd, Lu, in particular among the elements or mixtures of elements of the group consisting of La, Gd and Lu; and x is the molar rate of substitution of M with cerium, x being not less than 1 mol % and strictly less than 100 mol %. The invention also concerns a method for growing said monocrystalline scintillator material, and the use of said scintillator material as component of a scintillating detector in particular for industrial and medical purposes and in the oil industry.

Claims

1. A method of detecting radiation, comprising the steps of:

receiving said radiation with an inorganic scintillating material comprising M<sub>1−

x</sub>Ce_xCl₃ where M is chosen from the elements or the mixtures of elements of the group of the lanthanides and Y and where x is the molar level of substitution of M by cerium, where x is greater than or equal to 1 mol % and less than 100 mol %;

emitting light with said inorganic scintillating material in response to said step of receiving said radiation, wherein said emitted light has a fast scintillation component having an emission intensity of at least 4000 photons per MeV; and

detecting said light with a photodetector.

2. The method as claimed in claim 1, wherein M is chosen from the elements or the mixtures of elements of the group:

Y, La, Gd, Lu.

3. The method as claimed in claim 1, wherein M is lanthanum (La).

4. The method as claimed in claim 1, wherein x is greater than or equal to 2 mol %.

5. The method as claimed in claim 1, wherein x is greater than or equal to 4 mol %.

6. The method as claimed in claim 1, wherein x is less than or equal to 90 mol %.

7. The method as claimed in claim 1, wherein the energy resolution of the inorganic scintillating material is less than 5% for a measurement with gamma photons at 662 keV.

8. The method as claimed in claim 1, wherein x is greater than or equal to 2 mol % and wherein M is lanthanum (La).

9. The method as claimed in claim 1, wherein x is greater than or equal to 4 mol % and wherein M is lanthanum (La).

10. The method as claimed in claim 1, wherein the fast scintillation component has an emission intensity of at least 8000 photons per MeV.

11. The method as claimed in claim 3, wherein the fast scintillation component has an emission intensity of at least 8000 photons per MeV.

12. The method as claimed in claim 1, wherein the fast scintillation component has a decay time constant of at most 30 ns.

13. The method of claim 1, wherein the inorganic scintillating material has an energy resolution of at most 4% at 662 keV.

14. The method of claim 1, wherein the fast scintillation component has an emission intensity of at least 8000 photons per MeV and a decay time constant of at most 30 ns.

15. The method as claimed in claim 14, wherein the inorganic scintillating material has an energy resolution of at most 4% at 662 keV.

16. The method of claim 1, wherein the inorganic scintillating material consists of M₁₋

xCe_xCl₃.

17. A method of detecting radiation, comprising the steps of:

receiving said radiation with an inorganic scintillating material comprising M, Ce, and Cl wherein M is selected from the group consisting of the lanthanides, Y, and combinations thereof, and M is partially substituted by Ce, a molar level of substitution of M by Ce being greater than or equal to 1 mol % and less than 100 mol %;

emitting light with said inorganic scintillating material in response to said step of receiving said radiation; and

detecting said light with a photodetector.

18. The method as claimed in claim 17, wherein M is chosen from the elements or the mixtures of elements of the group:

Y, La, Gd, Lu.

19. The method as claimed in claim 17, wherein M is lanthanum (La).

20. The method as claimed in claim 17, wherein the inorganic scintillating material is in the form of a single crystal.

21. The method as claimed in claim 20, wherein the single crystal has a volume greater than 10 mm .

22. The method as claimed in claim 20, wherein the single crystal has a volume greater than 1 cm³.

23. The method as claimed in claim 20, wherein the single crystal has a volume greater than 10 cm³.

24. The method as claimed in claim 17, wherein the molar level of substitution of M by Ce is greater than or equal to 2 mol %.

25. The method as claimed in claim 17, wherein the molar level of substitution of M by Ce is greater than or equal to 4 mol %.

26. The method as claimed in claim 17, wherein the molar level of substitution of M by Ce is less than or equal to 90 mol %.

27. The method as claimed in claim 17, wherein the inorganic scintillating material comprises M₁₋

xCe_xCl₃ where x is the molar level of substitution of M by Ce.

28. The method as claimed in claim 17, wherein the inorganic scintillating material consists of M₁₋

xCe_xCl₃ where x is the molar level of substitution of M by Ce.

29. The method as claimed in claim 17, wherein the energy resolution of the inorganic scintillating material is less than 5% for a measurement with gamma photons at 662 keV.

30. The method as claimed in claim 17, wherein the scintillating material is a powder or a polycrystal.

31. A radiation detector comprising:

an inorganic scintillating material comprising M<sub>1−

x</sub>Ce_xCl₃ where M is chosen from the elements or the mixtures of elements of the group of the lanthanides and Y and where x is the molar level of substitution of M by cerium, where x is greater than or equal to 1 mol % and less than 100 mol %; and

a photodetector being coupled to said inorganic scintillating material, wherein when said inorganic scintillating material is exposed to radiation said inorganic scintillating material is capable of emitting light having a fast scintillation component with an emission intensity of at least 4000 photons per MeV.

32. The radiation detector as claimed in claim 31, wherein M is chosen from the elements or the mixtures of elements of the group of Y, La, Gd, Lu.

33. The radiation detector as claimed in claim 31, wherein M is lanthanum (La).

34. The radiation detector as claimed in claim 31, wherein the inorganic scintillating material is in the form of a single crystal.

35. The radiation detector as claimed in claim 34, wherein the single crystal has a volume greater than 10 mm³.

36. The radiation detector as claimed in claim 34, wherein the single crystal has a volume greater than 1 cm³.

37. The radiation detector as claimed in claim 34, wherein the single crystal has a volume greater than 10 cm³.

38. The radiation detector as claimed in claim 31, wherein x is less than or equal to 90 mol %.

39. The radiation detector as claimed in claim 31, wherein x is greater than or equal to 2 mol %.

40. The radiation detector as claimed in claim 31, wherein x is greater than or equal to 4 mol %.

41. The radiation detector as claimed in claim 31, wherein the energy resolution of the inorganic scintillating material is less than 5% for a measurement with gamma photons at 662 keV.

42. The radiation detector as claimed in claim 31, wherein the scintillating material is a powder or a polycrystal.

43. The radiation detector as claimed in claim 31, wherein x is less than or equal to 90 mol % and is greater than or equal to 4 mol % and wherein M is lanthanum (La).

44. The radiation detector as claimed in claim 31, wherein said fast scintillation component has a decay time constant of at most 30 ns.

45. The radiation detector of claim 31, wherein the inorganic scintillating material has an energy resolution of at most 4% at 662 keV.

46. The radiation detector of claim 31, wherein said fast scintillation component has an emission intensity of at least 8000 photons per MeV.

47. The radiation detector of claim 31, wherein said fast scintillation component has an emission intensity of at least 8000 photons per MeV and a decay time constant of at most 30 ns.

48. The radiation detector of claim 31, wherein said radiation includes gamma rays.

49. The radiation detector of claim 31, wherein said radiation includes X-rays.

50. A scintillation detector comprising:

an inorganic scintillating material comprising M, Ce, and Cl wherein M is selected from the group consisting of the lanthanides, Y, and combinations thereof, and M is partially substituted by Ce, a molar level of substitution of M by Ce being greater than or equal to 1 mol % and less than 100 mol %; and

a photodetector coupled to said inorganic scintillating material.

51. The scintillation detector as claimed in claim 50, where M is chosen from the elements or the mixtures of elements of the group:

Y, La, Gd, Lu.

52. The scintillation detector as claimed in claim 50, wherein M is lanthanum (La).

53. The scintillation detector as claimed in claim 50, wherein the inorganic scintillating material is in the form of a single crystal.

54. The scintillation detector as claimed in claim 53, wherein the single crystal has a volume greater than 10 mm³.

55. The scintillation detector as claimed in claim 53, wherein the single crystal has a volume greater than 1 cm³.

56. The scintillation detector as claimed in claim 53, wherein the single crystal has a volume greater than 10 cm³.

57. The scintillation detector as claimed in claim 50, wherein the molar level of substitution of M by Ce is greater than or equal to 2 mol %.

58. The scintillation detector as claimed in claim 50, wherein the molar level of substitution of M by Ce is greater than or equal to 4 mol %.

59. The scintillation detector as claimed in claim 50, wherein the molar level of substitution of M by Ce is less than or equal to 90 mol %.

60. The scintillation detector as claimed in claim 50, wherein the inorganic scintillation material comprises M₁₋

xCe_xCl₃ where x is the molar level of substitution of M by Ce.

61. The scintillation detector as claimed in claim 50, wherein the inorganic scintillating material consists of M₁₋

xCe_xCl₃ where x is the molar level of substitution of M by Ce.

62. The scintillation detector as claimed in claim 50, wherein the energy resolution of the inorganic scintillating material is less than 5% for a measurement with gamma photons at 662 keV.

63. The scintillation detector as claimed in claim 50, wherein the scintillating material is a powder or a polycrystal.

64. A method of generating a fast scintillation component with an emission intensity greater than 4000 ph/Mev, comprising:

exposing to radiation an inorganic scintillating material comprising M, Ce and Cl wherein M is selected from the elements or the mixtures of elements of the group of the lanthanides and Y, and M is partially substituted by Ce, a molar level of substitution of M by Ce being greater than or equal to 1 mol % and less than 100 mol %,

emitting light from said inorganic scintillating material in response to said exposing,

wherein said emitted light has a fast scintillation component having has an emission intensity greater than 4000 ph/Mev.

65. The method as claimed in claim 64, wherein M is chosen from the elements or the mixtures of elements of the group:

Y, La, Gd, Lu.

66. The method as claimed in claim 64, wherein M is lanthanum (La).

67. The method as claimed in claim 64, wherein the inorganic scintillating material is in the form of a single crystal.

68. The method as claimed in claim 67, wherein the single crystal has a volume greater than 10 mm³.

69. The method as claimed in claim 67, wherein the single crystal has a volume greater than 1 cm³.

70. The method as claimed in claim 67, wherein the single crystal has a volume greater than 10 cm³.

71. The method as claimed in claim 64, wherein the molar level of substitution of M by Ce is greater than or equal to 2 mol %.

72. The method as claimed in claim 64, wherein the molar level of substitution of M by Ce is greater than or equal to 4 mol %.

73. The method as claimed in claim 64, wherein the molar level of substitution of M by Ce is less than or equal to 90 mol %.

74. The method as claimed in claim 64, wherein the inorganic scintillating material comprises M₁₋

xCe_xCl₃ where x is the molar level of substitution of M by Ce.

75. The method as claimed in claim 64, wherein the inorganic scintillating material consists of M₁₋

xCe_xCl₃ where x is the molar level of substitution of M by Ce.

76. The method as claimed in claim 64, wherein the energy resolution of the inorganic scintillating material is less than 5% for a measurement with gamma photons at 662 keV.

77. The method as claimed in claim 64, wherein the scintillating material is a powder or a polycrystal.

78. A method of increasing the emission intensity of a fast scintillation component of an inorganic scintillating material when exposed to radiation to at least 4000 ph/Mev, said method comprising combining M, Ce and Cl to form an inorganic scintillating material, wherein M is selected from the elements or the mixtures of elements of the group of the lanthanides and Y, and wherein the molar level of Ce present in the inorganic scintillating material is greater than or equal to 1 mol % and less than 100 mol %.