SCINTILLATION CRYSTAL INCLUDING A RARE EARTH HALIDE, AND A RADIATION DETECTION SYSTEM INCLUDING THE SCINTILLATION CRYSTAL

• US 20120305778A1
• Filed: 06/05/2012
• Published: 12/06/2012
• Est. Priority Date: 06/06/2011
• Status: Abandoned Application

• Current Assignee: Luxium Solutions LLC
• Original Assignee: Saint-Gobain Ceramics & Plastics Incorporated (Compagnie De Saint-Gobain)
• Inventors: Menge, Peter R., Ouspenski, Vladimir
• Application Number:
  US13/488,756
• Publication Number:
  US 20120305778A1
• Time in Patent Office: Days
• US Class Current: 250/361.R
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3213 Strontium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3215 Barium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3227 Lanthanum oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3229 Cerium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3284 Zinc oxides, zincates, cadmium oxides, cadmiates, mercury oxides, mercurates or oxide forming salts thereof
• CPC Class Codes: C04B 2235/9646 Optical properties
• CPC Class Codes: C04B 35/5152 based on halogenides other than fluorides
• CPC Class Codes: C04B 35/553 based on fluorides
• CPC Class Codes: C09K 11/7772 Halogenides C09K11/7767 takes precedence
• CPC Class Codes: C09K 11/7773 with alkali or alkaline earth metal
• CPC Class Codes: C30B 11/04 adding crystallising materials or reactants forming it in situ to the melt
• CPC Class Codes: C30B 15/04 adding doping materials, e.g. for n-p-junction
• CPC Class Codes: C30B 29/12 Halides
• CPC Class Codes: G01T 1/202 the detector being a crystal
• CPC Class Codes: G21K 4/00 Conversion screens for the conversion of the spatial distribution of X-rays or particle radiation into visible images, e.g. fluoroscopic screens photographic processes using X-ray intensifiers G03C5/17; discharge tubes comprising luminescent screens H01J1/62; cathode ray tubes for X-ray conversion with optical output H01J31/50

Abstract

A scintillation crystal can include Ln_(1-y)RE_yX₃, wherein Ln represents a rare earth element, RE represents a different rare earth element, y has a value in a range of 0 to 1, and X represents a halogen. In an embodiment, RE is Ce, and the scintillation crystal is doped with Sr, Ba, or a mixture thereof at a concentration of at least approximately 0.0002 wt. %. In another embodiment, the scintillation crystal can have unexpectedly improved linearity and unexpectedly improved energy resolution properties. In a further embodiment, a radiation detection system can include the scintillation crystal, a photosensor, and an electronics device. Such a radiation detection system can be useful in a variety of radiation imaging applications.

Claims

1. A scintillation crystal comprising:

Ln(_1-y)RE_yX₃;

Me²⁺, wherein;

Ln represents a rare earth element;

Me²⁺ represents Sr, Ba, or any mixture thereof and has a concentration of at least approximately 0.0002 wt. %;

RE represents a different rare earth element;

y has a value in a range of 0 to 1; and

X represents a halogen.

2. A radiation detection system comprising:

the scintillation crystal of claim 1; and

a photosensor optically coupled to the scintillation crystal.

9. The scintillation crystal of claim 1;

wherein an energy resolution ratio is an energy resolution of the scintillation crystal divided by a different energy resolution of a different scintillation crystal of a different composition, wherein the energy resolution ratio is;

no greater than approximately 0.970 for energies in a range of 60 to 729 keV;

no greater than approximately 0.950 for energies in a range of 122 keV to 2615 keV;

no greater than approximately 0.920 for energies in a range of 583 keV to 2615 keV;

no greater than approximately 0.900 for energies in a range of 662 keV to 2615 keV;

no greater than approximately 0.985 for an energy of 60 keV;

no greater than approximately 0.980 for an energy of 122 keV;

no greater than approximately 0.980 for an energy of 239 keV;

no greater than approximately 0.970 for an energy of 511 keV;

no greater than approximately 0.970 for an energy of 583 keV;

no greater than approximately 0.970 for an energy of 662 keV;

no greater than approximately 0.970 for an energy of 729 keV;

no greater than approximately 0.950 for an energy of 2615 keV;

or any combination thereof.

30. The scintillation crystal of claim 1, wherein the scintillation crystal is doped with Sr.

31. The scintillation crystal of claim 1, wherein the Me²⁺ content in the scintillation crystal is at least approximately 0.0002 wt. %, at least approximately 0.0005 wt. %, or at least approximately 0.001 wt. %.

32. The scintillation crystal of claim 1, wherein the Me²⁺ content in the scintillation crystal is no greater than approximately 0.05 wt. %, no greater than approximately 0.03 wt. %, no greater than 0.02 wt. %, or no greater than approximately 0.009 wt. %.

39. The scintillation crystal of claim 1, wherein:

Ln includes La, Gd, Lu, or any mixture thereof, and

RE includes Ce, Eu, Pr, Tb, Nd, or any mixture thereof.

49. The scintillation crystal of claim 1, wherein the scintillation crystal is doped with Ba.

3. A scintillation crystal comprising:

Ln(_1-y)RE_yX₃, wherein;

Ln represents a rare earth element;

RE represents a different rare earth element;

y has a value in a range of 0 to 1; and

X represents a halogen; and

the scintillation crystal has a property including;

for a radiation energy range of 60 keV to 356 keV, the scintillation crystal has an averaged value for a departure from perfect linearity of no less than approximately -0.35%;

for a radiation energy range of 2000 keV to 2600 keV, the scintillation crystal has an averaged value for a departure from perfect linearity of no greater than approximately 0.07%;

for a radiation energy range of 60 keV to 356 keV, the scintillation crystal has an absolute value for a furthest departure from perfect linearity of no greater than approximately 0.7%;

or

any combination thereof.

37. The scintillation crystal of claim 3, wherein the averaged value for the departure from perfect linearity (DFPL_average) is determined by:

48. The scintillation crystal of claim 3, wherein an energy resolution ratio is an energy resolution of the scintillation crystal divided by a different energy resolution of a different scintillation crystal of a different composition, wherein the energy resolution ratio is:

no greater than approximately 0.970 for energies in a range of 60 to 729 keV;

no greater than approximately 0.950 for energies in a range of 122 keV to 2615 keV;

no greater than approximately 0.920 for energies in a range of 583 keV to 2615 keV;

no greater than approximately 0.900 for energies in a range of 662 keV to 2615 keV;

no greater than approximately 0.985 for an energy of 60 keV;

no greater than approximately 0.980 for an energy of 122 keV;

no greater than approximately 0.980 for an energy of 239 keV;

no greater than approximately 0.970 for an energy of 511 keV;

no greater than approximately 0.970 for an energy of 583 keV;

no greater than approximately 0.970 for an energy of 662 keV;

no greater than approximately 0.970 for an energy of 729 keV;

no greater than approximately 0.950 for an energy of 2615 keV;

or any combination thereof.

50. The scintillation crystal of claim 3, further comprising Me²⁺, wherein an Me²⁺ content in the scintillation crystal is at least approximately 0.0002 wt. %, at least approximately 0.0005 wt. %, or at least approximately 0.001 wt. %.

51. The scintillation crystal of claim 50, wherein the Me²⁺ content in the scintillation crystal is no greater than approximately 0.05 wt. %, no greater than approximately 0.03 wt. %, no greater than 0.02 wt. %, or no greater than approximately 0.009 wt. %.

4. A scintillation crystal comprising:

Ln(_1-y)RE_yX₃, wherein;

Ln represents a rare earth element;

RE represents a different rare earth element;

y has a value in a range of 0 to 1; and

X represents a halogen; and

an energy resolution ratio is an energy resolution of the scintillation crystal divided by a different energy resolution of a different scintillation crystal having a different composition, wherein the energy resolution ratio is;

no greater than approximately 0.970 for energies in a range of 60 to 729 keV;

no greater than approximately 0.950 for energies in a range of 122 keV to 2615 keV;

no greater than approximately 0.920 for energies in a range of 583 keV to 2615 keV;

no greater than approximately 0.900 for energies in a range of 662 keV to 2615 keV;

no greater than approximately 0.985 for an energy of 60 keV;

no greater than approximately 0.980 for an energy of 122 keV;

no greater than approximately 0.980 for an energy of 239 keV;

no greater than approximately 0.970 for an energy of 511 keV;

no greater than approximately 0.970 for an energy of 583 keV;

no greater than approximately 0.970 for an energy of 662 keV;

no greater than approximately 0.970 for an energy of 729 keV;

no greater than approximately 0.950 for an energy of 2615 keV;

or any combination thereof.

22. The scintillation crystal claim 4, wherein an energy resolution for the scintillation crystal is determined from an energy spectrum obtained using the scintillation crystal, a photomultiplier tube, a window disposed between the scintillation crystal and the photomultiplier tube, and a multi-channel analyzer coupled to the photomultiplier tube,

wherein:

the scintillation crystal has a shape of a right circular cylinder with diameter of approximately 64 mm and length of approximately 75 mm, and the scintillation crystal is wrapped with a reflector on the sides and one end;

the window includes sapphire or quartz;

the photomultiplier tube includes a linearly focused, non-saturated photomultiplier; and

the multi-channel analyzer is configured to perform bi-polar shaping at a 0.25 micro-s shaping time; and

the energy resolution is no greater than approximately 6.40% at 122 keV, no greater than approximately 2.90% at 662 keV, no greater than approximatelyl.90% at 2615 keV, or any combination thereof.

23. The scintillation crystal of claim 22, wherein the energy resolution is no greater than approximately 6.40%.

25. The scintillation crystal of claim 22, wherein the energy resolution is no greater than approximately 2.90% at 662 keV.

27. The scintillation crystal of claim 22, wherein the energy resolution is no greater than approximately 1.90% at 2615 keV.

52. The scintillation crystal of claim 4, further comprising Me²⁺, wherein an Me²⁺ content in the scintillation crystal is at least approximately 0.0002 wt. %, at least approximately 0.0005 wt. %, or at least approximately 0.001 wt. %.

53. The scintillation crystal of claim 52, wherein the Me²⁺ content in the scintillation crystal is no greater than approximately 0.05 wt. %, no greater than approximately 0.03 wt. %, no greater than 0.02 wt. %, or no greater than approximately 0.009 wt. %.

5. to 8. (canceled)

10. to 21. (canceled)

24. (canceled)

26. (canceled)

28. to 29. (canceled)

33-36. -36. (canceled)

38. (canceled)

40-47. -47. (canceled)