METHOD OF FORMING A SCINTILLATION CRYSTAL AND A RADIATION DETECTION APPARATUS INCLUDING A SCINTILLATION CRYSTAL INCLUDING A RARE EARTH HALIDE

• US 20190146102A1
• Filed: 12/19/2018
• Published: 05/16/2019
• Est. Priority Date: 10/28/2012
• Status: Active Grant

• Current Assignee: Stichting Voor de Technische Wetenschappen, Technische Universiteit Delft
• Original Assignee: Stichting Voor de Technische Wetenschappen, Universite De Berne
• Inventors: Dorenbos, Pieter, Kramer, Karl W.
• Granted Patent: US 10,564,298 B2
• Time in Patent Office: Days
• CPC Class Codes: C09K 11/7772 Halogenides C09K11/7767 takes precedence
• CPC Class Codes: C09K 11/7773 with alkali or alkaline earth metal
• CPC Class Codes: G01T 1/2006 using a combination of a scintillator and photodetector which measures the means radiation intensity
• CPC Class Codes: G01T 1/2023 Selection of materials see provisionally also G01T1/202
• CPC Class Codes: G21K 2004/06 with a phosphor layer
• CPC Class Codes: G21K 4/00 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

Abstract

A scintillation crystal can include Ln_(1-y)RE_yX₃, 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.

Claims

1. A radiation detection apparatus comprising:

a scintillation crystal including Ln_(1-y)RE_yX₃;

Ca, 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; and

the scintillation crystal is formed from a melt having a Ca concentration of at least approximately 0.02 wt. %; and

an optical interface optically coupled to the scintillation crystal.

2. A radiation detection apparatus comprising:

a scintillation crystal comprising 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%;

a photosensor; and

an optical interface disposed between and optically coupled to the scintillation crystal to the photosensor.

3. The radiation detection apparatus of claim 2, wherein the melt has the Ca concentration of at least approximately 0.08 wt. %.

4. The radiation detection apparatus of claim 2, wherein y is no greater than approximately 0.5 and at least approximately 0.005.

5. The radiation detection apparatus of claim 2, wherein y is in a range of approximately 0.01 to approximately 0.09.

6. The radiation detection apparatus of claim 2, wherein Ln is La, RE is Ce, and X is Br.

7. The radiation detection apparatus of claim 2, wherein y is approximately 1.0 f.u.

8. The radiation detection apparatus of claim 7, 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%

9. The radiation detection apparatus of claim 2, 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%.

10. The radiation detection apparatus of claim 2, 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.

11. The radiation detection apparatus of claim 10, wherein the energy resolution ratio is no greater than approximately 0.95 for the energy of 8 keV.

12. The radiation detection apparatus of claim 10, wherein the energy resolution ratio is no greater than approximately 0.95 for the energy of 13 keV.

13. The radiation detection apparatus of claim 10, wherein the energy resolution ratio is no greater than approximately 0.95 for the energy of 17 keV.

14. The radiation detection apparatus of claim 10, wherein the energy resolution ratio is no greater than approximately 0.95 for the energy of 22 keV.

15. The radiation detection apparatus of claim 13, wherein the energy resolution ratio is no greater than approximately 0.95 for the energy of 26 keV.

16. The radiation detection apparatus of claim 10, wherein an energy resolution ratio is no greater than approximately 0.95 for the energy of 32 keV.

17. The radiation detection apparatus of claim 2, wherein the radiation detection apparatus is a medical imaging system or a well logging apparatus.

18. A radiation detection apparatus comprising:

a scintillation crystal including La_(1-y)Ce_yBr₃;

Ca, 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

the scintillation crystal is formed from a melt having a Ca concentration of at least approximately 0.02 wt. %; and

an optical interface optically coupled to the scintillation crystal.

19. The radiation detection apparatus of claim 18, wherein the Ca concentration is no greater than approximately 1.0 wt. %.

20. The radiation detection apparatus of claim 18, wherein the a scintillation crystal has a formula of CeBr₃:

Ca.