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