Scintillation crystal, a radiation detection system including the scintillation crystal, and a method of using the radiation detection system

Patent metadata

Field	Value
Publication number	US-10947452-B2
Application number	US-201916560468-A
Country	US
Kind code	B2
Filing date	Sep 4, 2019
Priority date	Jun 6, 2011
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

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, 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.

First claim

What is claimed is:

1. A method comprising:
placing precursors into a crucible;
melting the precursors to form a melt; and
forming a scintillation crystal from the melt, wherein the scintillation crystal comprises La (1-y) RE y X 3 :Me 2+ , wherein:
RE represents a different rare earth element than La;
y has a value in a range of 0 to 0.5;
X represents a halogen; and

Me 2+ represents Sr, Ba, or any mixture thereof and has a concentration in a range of 0.0002 wt. % to 0.05 wt. %.

2. The method of claim 1 , wherein the scintillation crystal has a property including:
for a radiation energy range of 60 keV to 356 keV, the scintillation crystal has an average value for a departure from perfect linearity of no less than −0.35%;
for a radiation energy range of 2000 keV to 2600 keV, the scintillation crystal has an average value for a departure from perfect linearity of no greater than 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 0.7%; or
any combination thereof.

3. The method of claim 2 , wherein the average value for the departure from perfect linearity (DFPL average ) is determined by:

DFPL
average

=

∫

E
lower

E
upper

⁢

DFPL
⁡

(

E
i

)

·

dE
i

E
upper

-

E
lower

,
where

DFPL(Ei) is DFPL at energy E i ;
E upper is the upper limit of the energy range; and
E lower is the lower limit of the energy range.

4. The method of claim 1 , wherein the concentration of Me 2+ is no greater than 0.03 wt. %.

5. The method of claim 4 , wherein y has a value in a range of 0.0001 to 0.2.

6. The method of claim 1 , wherein RE is Ce.

7. The method of claim 6 , wherein y has a value in a range of 0.0001 to 0.2.

8. The method of claim 1 , wherein Me 2+ represents Sr.

9. The method of claim 1 , wherein Me 2+ represents Ba.

10. The method of claim 1 , wherein Me 2+ does not include any divalent metal element other than Sr, Ba, or any combination thereof.

11. The method of claim 1 , wherein the concentration of Me 2+ is in a range of 0.005 wt. % to 0.02 wt. %.

12. The method of claim 1 , further comprising placing the scintillation crystal within casing.

13. The method of claim 2 , further comprising placing an optical interface adjacent to a surface of the scintillation crystal.

14. The method of claim 1 , wherein the precursors comprise a rare earth halide precursor.

15. The method of claim 1 , wherein the precursors comprise a strontium halide, a barium halide, or any combination thereof.

16. The method of claim 1 , further comprising roughening a surface of the scintillation crystal.

17. 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 to form a melt; and
forming a scintillation crystal from the melt, wherein the scintillation crystal comprises La (1-y) RE y X 3 :Me 2+ , wherein:
RE represents a rare earth element other than La;
y has a value in a range of 0 to 0.5;
X represents a halogen; and

Me 2+ represents Sr, Ba, or any mixture thereof and has a concentration in a range of 0.0002 wt. % to 0.05 wt. %.

18. The method of claim 17 , wherein the scintillation crystal has a property including:
for a radiation energy range of 60 keV to 356 keV, the scintillation crystal has an average value for a departure from perfect linearity of no less than −0.35%;
for a radiation energy range of 2000 keV to 2600 keV, the scintillation crystal has an average value for a departure from perfect linearity of no greater than 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 0.7%; or
any combination thereof.

19. A method, comprising:
placing precursors into a crucible;
melting the precursors to form a melt;
contacting the melt with a seed crystal; and
using the seed crystal to form a scintillation crystal from the melt, wherein the scintillation crystal comprises La (1-y) RE y X 3 :Me 2+ , wherein:
RE represents a rare earth element other than La;
y has a value in a range of 0 to 0.5;
X represents a halogen; and

Me 2+ represents Sr, Ba, or any mixture thereof and has a concentration in a range of 0.0002 wt. % to 0.05 wt. %.

20. The method of claim 19 , wherein the scintillation crystal has a property including:
for a radiation energy range of 60 keV to 356 keV, the scintillation crystal has an average value for a departure from perfect linearity of no less than −0.35%;
for a radiation energy range of 2000 keV to 2600 keV, the scintillation crystal has an average value for a departure from perfect linearity of no greater than 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 0.7%; or
any combination thereof.

Assignees

• Saint Gobain Ceramics

Inventors

• Menge Peter R
• Ouspenski Vladimir

Classifications

• C04B2235/3229

  Cerium oxides or oxide-forming salts thereof · CPC title

• G01T1/202

  the detector being a crystal · CPC title

• C04B2235/9646

  Optical properties · CPC title

• C04B2235/3227

  Lanthanum oxide or oxide-forming salts thereof · CPC title

• C04B35/553

  based on fluorides · CPC title