Scintillator and radiation detector

Patent metadata

Field	Value
Publication number	US-12044812-B2
Application number	US-202318372820-A
Country	US
Kind code	B2
Filing date	Sep 26, 2023
Priority date	Mar 26, 2021
Publication date	Jul 23, 2024
Grant date	Jul 23, 2024

Abstract

A scintillator, having a composition represented by the following general formula (1), including a substitution element A, the substitution element A comprising at least La, and a total molar content of the substitution element A being 0.00001 mol or more and 0.05 mol or less in 1 mol of the scintillator, and further including an activator element B, the activator element B being constituted from Ce, having a perovskite-type crystal structure, and exhibiting a linear transmittance of light at a wavelength of 800 nm, at a thickness of 1.9 mm, of 30% or more. QM x O 3y . . . (1): wherein Q represents one or more elements selected from the group consisting of Ca, Sr and Ba; M represents Hf; Q and M are each optionally substituted with other element at a proportion of 20% by mol or less; and x and y respectively satisfy 0.5≤x≤1.5 and 0.7≤y≤1.5.

First claim

What is claimed is:

1. A scintillator,
having a composition represented by the following general formula (1),
QM x O 3y   (1)

wherein
Q represents one or more elements selected from the group consisting of Ca, Sr and Ba;
M represents Hf,
x and y respectively satisfy 0.5≤x≤1.5 and 0.7≤y≤1.5;
the scintillator:
comprises a substitution element A comprising at least La, and a total molar content of the substitution element A being 0.00001 mol or more and 0.05 mol or less in 1 mol of the scintillator,
further comprises an activator element B, the activator element B being constituted from Ce,
has a perovskite-type crystal structure, and
exhibits a linear transmittance of light at a wavelength of 800 nm, at a thickness of 1.9 mm, of 30% or more.

2. The scintillator according to claim 1 , wherein, when the total molar content of the substitution element A and the total molar content of the activator element B, contained in 1 mol of the scintillator, are designated respectively as a and b, a+b satisfies 0.0055 mol or more and 0.024 mol or less.

3. The scintillator according to claim 1 , wherein, when the total molar content of the substitution element A and the total molar content of the activator element B, contained in 1 mol of the scintillator, are designated respectively as a and b, [a+(b×1.8)] satisfies 0.006 mol or more and 0.03 mol or less.

4. The scintillator according to claim 1 , wherein the scintillator is a single crystal or a sintered body.

5. The scintillator according to claim 1 , having a columnar shape, a flat plate shape or a curved plate shape, and having a height of 1 mm or more.

6. The scintillator according to claim 1 , wherein a linear transmittance of light at a wavelength of 390 nm, at a thickness of 1.9 mm, is 3% or more.

7. The scintillator according to claim 1 , wherein a fluorescence decay time is 20 ns or less.

8. The scintillator according to claim 1 , wherein, when the maximum value of a fluorescence intensity in irradiation with γ-ray is 100%, a fluorescence intensity at a time point after 100 ns from a time point at which a fluorescence intensity reaches the maximum value is 3% or less.

9. A radiation detector comprising the scintillator according to claim 1 .

10. A radiation inspection apparatus comprising the radiation detector according to claim 9 .

11. The scintillator according to claim 1 , Q represents Ca.

12. The scintillator according to claim 1 , Q represents Sr.

13. The scintillator according to claim 1 , Q represents Ba.

14. The scintillator according to claim 1 , wherein Q and M are substituted with the substitution element A.

15. The scintillator according to claim 1 , wherein Q and/or M is individually substituted with an element other than a substitution element A and an activator element B.

16. The scintillator according to claim 1 , wherein Q and/or M is individually substituted with an element other than Q and M at a proportion of 20% by mol or less.

17. A method for producing a scintillator, the method comprising:
mixing a raw material to obtain a raw material mixture; and
heat-treating the raw material mixture to obtain a synthetic powder,
wherein
the raw material contains at least HfO 2 having a purity of 99.0% by mol or less, and
the scintillator is a scintillator represented by the following general formula (1),
QM x O 3y   (1)

wherein
Q represents one or more elements selected from the group consisting of Ca, Sr and Ba,
M represents Hf,
x and y respectively satisfy 0.5≤x≤1.5 and 0.7≤y≤1.5;
the scintillator:
comprises a substitution element A comprising at least-La, and a total molar content of the substitution element A being 0.00001 mol or more and 0.05 mol or less in 1 mol of the scintillator,
further comprises as an activator element B, the activator element B being constituted from Ce,
has a perovskite-type crystal structure and
exhibits a linear transmittance of light at a wavelength of 800 nm, at a thickness of 1.9 mm, of 30% or more.

18. The method for producing a scintillator according to claim 17 , further comprising:
pressure-molding the synthetic powder to obtain a pressure-molded body; and
firing the pressure-molded body to obtain a fired product.

19. The method for producing a scintillator according to claim 17 , further comprising:
pressure-molding the synthetic powder to obtain a pressure-molded body;
firing the pressure-molded body to obtain a fired product; and
annealing the fired product, after the firing.

Assignees

• Mitsubishi Chem Corp
• Univ Tohoku

Inventors

• Hazu Koji
• Yamahara Keiji
• Kurosawa Shunsuke
• Yoshikawa Akira

Classifications

• G01T1/2018

  Scintillation-photodiode combinations · CPC title

• C01P2002/52

  containing elements as dopants · CPC title

• C01P2002/34

  perovskite-type (ABO3) · CPC title

• C01G27/00

  Compounds of hafnium · CPC title

• C01P2006/80

  Compositional purity · CPC title