Method of forming a scintillation crystal and a radiation detection apparatus including a scintillation crystal including a rare earth halide

Patent metadata

Field	Value
Publication number	US-2016200972-A1
Application number	US-201615077042-A
Country	US
Kind code	A1
Filing date	Mar 22, 2016
Priority date	Oct 28, 2012
Publication date	Jul 14, 2016
Grant date	—

Abstract

A scintillation crystal can include Ln (1-y) RE y X 3 , 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, the scintillation crystal is doped with a Group 1 element, a Group 2 element, or a mixture thereof, and the scintillation crystal is formed from a melt having a concentration of such elements or mixture thereof of at least approximately 0.02 wt. %. In another embodiment, the scintillation crystal can have unexpectedly improved proportionality and unexpectedly improved energy resolution properties. In a further embodiment, a radiation detection apparatus can include the scintillation crystal, a photosensor, and an electronics device. Such a radiation detection apparatus can be useful in a variety of applications.

First claim

What is claimed is:

1 . A method, comprising:
placing into a crucible precursors including:
a rare earth halide precursor; and
a dopant precursor that includes a halide of a Group 1 element or a Group 2 element;
melting the precursors to form a melt, wherein a concentration of all Group 1 and Group 2 halides is at least approximately 0.02 wt. %; and forming a scintillation crystal including Ln (1-y) RE y X 3 :Me, 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;
X represents a halogen;
Me represents a Group 1 element, a Group 2 element, or any mixture thereof; and
optically coupling an optical interface to the scintillation crystal.

2 . The method of claim 1 , wherein Me is Ca.

3 . The method of claim 1 , wherein Me is Li.

4 . The method of claim 1 , wherein the concentration of all Group 1 and Group 2 halides in the melt is no greater than approximately 1.0 wt. %.

5 . The method of claim 1 , wherein y is no greater than approximately 0.5 and at least approximately 0.005.

6 . The method of claim 1 , wherein y is in a range of approximately 0.01 to approximately 0.09.

7 . The method of claim 1 , wherein Ln is La, RE is Ce, and X is Br.

8 . The method of claim 1 , wherein y is approximately 1.0 f.u.

9 . The method of claim 1 , wherein for a radiation energy range of 13 keV to 30 keV, the scintillation crystal has a PR dev average of no greater than approximately 14%, or for a radiation energy range of 30 keV to 60 keV, the scintillation crystal has a PR dev average of no greater than approximately 8.0%

10 . The method of claim 1 , wherein:
for a radiation energy range of 11 keV to 30 keV, the scintillation crystal has a PR dev average of no greater than approximately 8.0%; or for a radiation energy range of 30 keV to 60 keV, the scintillation crystal has the PR dev average of no greater than approximately 3.6%.

11 . The method 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 0.95 for an energy of 8 keV; no greater than approximately 0.95 for an energy of 13 keV; no greater than approximately 0.95 for an energy of 17 keV; no greater than approximately 0.95 for an energy of 22 keV; no greater than approximately 0.95 for an energy of 26 keV; no greater than approximately 0.95 for an energy of 32 keV; or no greater than approximately 0.97 for an energy of 44 keV.

12 . The method of claim 11 , wherein the energy resolution ratio is no greater than approximately 0.95 for the energy of 8 keV.

13 . The method of claim 11 , wherein the energy resolution ratio is no greater than approximately 0.95 for the energy of 13 keV.

14 . The method of claim 11 , wherein the energy resolution ratio is no greater than approximately 0.95 for the energy of 17 keV.

15 . The method of claim 11 , wherein the energy resolution ratio is no greater than approximately 0.95 for the energy of 22 keV.

16 . The method of claim 11 , wherein the energy resolution ratio is no greater than approximately 0.95 for the energy of 26 keV.

17 . The method of claim 11 , wherein an energy resolution ratio is no greater than approximately 0.95 for the energy of 32 keV.

18 . The method of claim 1 , further comprising optically coupling a photosensor to the optical interface.

19 . A method, comprising:
placing into a crucible precursors including:
a rare earth halide precursor; and
a dopant precursor that includes a strontium halide, a barium halide, or any combination thereof;
melting the precursors; forming a scintillation crystal including a rare earth halide, wherein:
for a radiation energy range of 11 keV to 30 keV, the scintillation crystal has an nPR dev average of no greater than approximately 8.0%; or
for a radiation energy range of 30 keV to 60 keV, the scintillation crystal has the nPR dev average of no greater than approximately 3.6%; and
optically coupling an optical interface to the scintillation crystal.

20 . The method of claim 19 , further comprising optically coupling a photosensor to the optical interface.

Assignees

• Stichting Tech Wetenschapp
• Saint Gobain Ceramics
• Univ Berne

Inventors

• Dorenbos Pieter
• Menge Peter R
• Ouspenski Vladimir
• Krämer Karl W

Classifications

• G21K4/00

  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) · CPC title

• G21K2004/06

  with a phosphor layer · CPC title

• G01T1/2006

  using a combination of a scintillator and photodetector which measures the means radiation intensity · CPC title

• C09K11/7772

  Halogenides (C09K11/7767 takes precedence) · CPC title

• C09K11/7773 Primary

  with alkali or alkaline earth metal · CPC title