Scintillator and radiation detector

Patent metadata

Field	Value
Publication number	US-11939504-B2
Application number	US-202217847789-A
Country	US
Kind code	B2
Filing date	Jun 23, 2022
Priority date	Dec 25, 2019
Publication date	Mar 26, 2024
Grant date	Mar 26, 2024

Abstract

The present invention aims to provide a scintillator which has a short fluorescence decay time, whose fluorescence intensity after a period of time following radiation irradiation is low, and which shows largely improved light-transmittance. A scintillator represented by the following General Formula (1), the scintillator including Zr, having a Zr content of not less than 1500 ppm by mass therein, and being a block of a sintered body. Q x M y O 3z :A . . . (1) (wherein in General Formula (1), Q includes at least one or more kinds of divalent metallic elements; M includes at least Hf; and x, y, and z independently satisfy 0.5≤x≤1.5, 0.5≤y≤1.5, and 0.7≤z≤1.5, respectively).

First claim

What is claimed is:

1. A scintillator represented by the following General Formula (1), the scintillator comprising Zr, having a Zr content of not less than 1500 ppm by mass therein, and being a block of a sintered body,
Q x M y O 3z ,  (1)

wherein in General Formula (1), Q includes at least one or more kinds of divalent metallic elements; M includes at least Hf; and x, y, and z independently satisfy 0.5≤x≤1.5, 0.5≤y≤1.5, and 0.7≤z≤1.5, respectively.

2. The scintillator according to claim 1 , wherein the Zr content is not more than 21,000 ppm by mass.

3. The scintillator according to claim 2 , wherein the Zr content is not more than 5000 ppm by mass.

4. The scintillator according to claim 1 , wherein the divalent metallic element(s) include(s) one or more kinds of elements selected from the group consisting of Ba, Sr, and Ca.

5. The scintillator according to claim 1 , further comprising one or more kinds of elements selected from the group consisting of Ce, Pr, Nd, Eu, Tb, and Yb as an activator(s).

6. The scintillator according to claim 1 , having a columnar shape, flat plate shape, or curved plate shape, and having a height of not less than 1 mm.

7. The scintillator according to claim 1 , having a fluorescence decay time of not more than 30 ns.

8. The scintillator according to claim 1 , having a fluorescence decay time of not more than 20 ns.

9. The scintillator according to claim 1 , wherein the linear transmittance of light having a wavelength of 390 nm at a thickness of 1.6 mm is not less than 1%.

10. The scintillator according to claim 1 , wherein the linear transmittance of light having a wavelength of 800 nm at a thickness of 1.6 mm is not less than 5%.

11. The scintillator according to claim 1 , wherein, upon irradiation with γ-ray, the fluorescence intensity 100 ns after the time when the fluorescence intensity reaches the maximum value is not more than 2% with respect to the maximum value of fluorescence intensity, which is taken as 100%.

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

13. A radiation inspection apparatus comprising a radiation detector,
the radiation detector comprising the scintillator according to claim 1 .

14. A method of producing a scintillator, the method comprising:
a raw material mixing step of mixing raw materials to obtain a raw material mixture; and
a synthesis step of subjecting the raw material mixture to heat treatment to obtain a synthetic powder;
the raw materials comprising at least HfO 2 , having a purity of not more than 99.0 mol %,
the scintillator being a scintillator represented by the following General Formula (1), the scintillator comprising Zr, having a Zr content of not less than 1500 ppm by mass therein, and being a block of a sintered body,
O x M y O 3z ,  (1)

wherein in General Formula (1), Q includes at least one or more kinds of divalent metallic elements; M includes at least Hf; and x, y, and z independently satisfy 0.5≤x≤1.5, 0.5≤y≤1.5, and 0.7≤z≤1.5, respectively.

15. The method of producing a scintillator according to claim 14 , wherein the Zr content in the HfO 2 is not less than 1500 ppm by mass.

16. The method of producing a scintillator according to claim 14 , further comprising:
a pressure molding step of pressure-molding the synthetic powder to obtain a pressure-molded body; and
a firing step of firing the pressure-molded body to obtain a fired product.

17. The method of producing a scintillator according to claim 14 , comprising:
a pressure molding step of pressure-molding the synthetic powder to obtain a pressure-molded body;
a firing step of firing the pressure-molded body to obtain a fired product; and
an annealing step of annealing the fired product after the firing step.

Assignees

• Mitsubishi Chem Corp
• Univ Tohoku

Inventors

• Hazu Koji
• Horibe Kentaro
• Kawano Tetsuya
• Yamahara Keiji
• Kurosawa Shunsuke
• Yoshikawa Akira

Classifications

• C09K11/7715 Primary

  containing cerium · CPC title

• C09K11/55

  containing beryllium, magnesium, alkali metals or alkaline earth metals · CPC title

• G01T1/2023

  Selection of materials · CPC title

• C09K11/7718 Primary

  with alkaline earth metals · CPC title

• C04B2235/3215

  Barium oxides or oxide-forming salts thereof · CPC title