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-10053624-B2
Application number	US-201715710509-A
Country	US
Kind code	B2
Filing date	Sep 20, 2017
Priority date	Jun 6, 2011
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

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 scintillation crystal comprising 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 1;
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 scintillation crystal 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 scintillation crystal 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 scintillation crystal of claim 1 , wherein the concentration of Me 2+ is no greater than 0.03 wt. %.

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

6. The scintillation crystal of claim 1 , wherein y has a value in a range of 0.001 to 0.5.

7. The scintillation crystal of claim 1 , wherein RE is Ce.

8. The scintillation crystal of claim 1 , wherein X is Br.

9. A radiation detection system comprising:
a scintillation crystal including 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 1;
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. %; and

a photosensor optically coupled to the scintillation crystal.

10. The radiation detection system of claim 9 , further comprising an electronics module coupled to the photosensor.

11. The radiation detection system of claim 10 , wherein the electronics module comprises an amplifier, a pre-amplifier, a discriminator, an analog-to-digital signal converter, a photon counter, another electronic component, or any combination thereof.

12. The radiation detection system of claim 9 , 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.

13. The radiation detection system of claim 12 , 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.

14. The radiation detection system of claim 9 , wherein RE is Ce, and X is Br.

15. A method comprising:
providing a radiation detection system including a scintillation crystal that includes 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 1;
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. %; and

exposing the scintillation crystal to a radioactive material; and
determine a performance characteristic at different energies.

16. The method of claim 15 , wherein determining the performance characteristic comprises determining a departure from perfect linearity for the scintillation crystal, wherein:
for a radiation energy range of 60 keV to 356 keV, an average value for the departure from perfect linearity of no less than −0.35%;
for a radiation energy range of 2000 keV to 2600 keV, an average value for the departure from perfect linearity of no greater than 0.07%;
for a radiation energy range of 60 keV to 356 keV, an absolute value for a furthest departure from perfect linearity of no greater than 0.7%; or
any combination thereof.

17. The method of claim 16 , determining the departure from perfect linearity is performed such

Assignees

• Saint Gobain Ceramics

Inventors

• Menge Peter R
• Ouspenski Vladimir

Classifications

• C04B2235/3284

  Zinc oxides, zincates, cadmium oxides, cadmiates, mercury oxides, mercurates or oxide forming salts thereof · CPC title

• C04B2235/3213

  Strontium oxides or oxide-forming salts thereof · CPC title

• C09K11/7773

  with alkali or alkaline earth metal · CPC title

• C04B35/5152

  based on halogenides other than fluorides · CPC title

• C04B2235/3206

  Magnesium oxides or oxide-forming salts thereof · CPC title