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 well logging apparatus comprising:
a scintillation crystal including La (i-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
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.
2. The well logging apparatus of claim 1 , 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.
3. The well logging apparatus of claim 1 , wherein the concentration of Me 2+ is no greater than 0.03 wt. %.
4. The well logging apparatus of claim 1 , wherein the concentration of Me 2+ is in a range of 0.005 wt. % to 0.02 wt. %.
5. The well logging apparatus of claim 1 , wherein y has a value in a range of 0.001 to 0.5.
6. The well logging apparatus of claim 1 , wherein RE is Ce.
7. The well logging apparatus of claim 1 , wherein X is Br.
8. A medical imaging apparatus 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. %;
a photosensor optically coupled to the scintillation crystal; and
an electronics module coupled to the photosensor.
9. The medical imaging apparatus of claim 8 , 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.
10. The medical imaging apparatus of claim 8 , 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.
11. The medical imaging apparatus of claim 10 , 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.
12. The medical imaging apparatus of claim 8 , wherein RE is Ce, and X is Br.
13. The medical imaging apparatus of claim 8 , wherein the medical imaging device is a positron emission tomography apparatus.
14. The medical imaging apparatus of claim 8 , wherein the medical imaging device is a single positron emission computer tomography apparatus.
15. The medical imaging device of claim 8 , wherein y has a value in a range of 0.001 to 0.5.
16. A security inspection apparatus 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. %.
17. The security inspection apparatus of claim 16 , wherein the concentration of Me 2+ is no greater than 0.03 wt. %.
18. The security inspection apparatus of claim 16 , wherein the concentration of Me 2+ is in a range of 0.005 wt. % to 0.02 wt. %.
19. The security inspection apparatus of claim 16 , wherein y has a value in a range of 0.001 to 0.5.