Ceramic scintillator and its production method, and scintillator array and radiation detector

Patent metadata

Field	Value
Publication number	US-2016251573-A1
Application number	US-201415027796-A
Country	US
Kind code	A1
Filing date	Sep 10, 2014
Priority date	Oct 8, 2013
Publication date	Sep 1, 2016
Grant date	—

Abstract

A method for producing a ceramic scintillator comprising the steps of mixing a rare earth compound with sulfuric acid and/or sulfate to cause their reaction to obtain a product; calcining the product to obtain calcined powder; reducing the calcined powder to obtain rare earth oxysulfide powder; molding the rare earth oxysulfide powder to obtain a green body; and sintering the green body; a pulverization step being conducted to adjust the particle sizes of the product and/or the calcined powder at least before the reduction step.

First claim

1 . A method for producing a ceramic scintillator comprising the steps of
mixing a rare earth compound with sulfuric acid and/or sulfate to cause their reaction to obtain a product; calcining said product to obtain calcined powder; reducing said calcined powder to obtain rare earth oxysulfide powder; molding said rare earth oxysulfide powder to obtain a green body; and sintering said green body; a pulverization step being conducted to adjust the particle sizes of the product and/or the calcined powder at least before the reduction step.

2 . The method for producing a ceramic scintillator according to claim 1 , wherein said mixing step is followed by said pulverization step, and by said calcining step at 1000° C. or lower; and wherein said reduction step is conducted at 900° C. or lower.

3 . The method for producing a ceramic scintillator according to claim 1 , wherein said calcining step is followed by said pulverization step, and by said reduction step at 900° C. or lower.

4 . The method for producing a ceramic scintillator according to claim 1 , wherein mixing in a liquid is conducted in said mixing step; and
wherein wet pulverization is conducted in said pulverization step.

5 . The method for producing a ceramic scintillator according to claim 1 , wherein a pulverization step for adjusting the particle sizes of said rare earth oxysulfide powder is not conducted after said reduction step.

6 . The method for producing a ceramic scintillator according to claim 1 , wherein said sintering step is conducted in an inert atmosphere without applying higher pressure than atmospheric pressure to said green body.

7 . The method for producing a ceramic scintillator according to claim 1 , wherein said rare earth compound is at least one selected from the group consisting of oxides, hydroxides, halides, nitrates, sulfates, acetates, phosphates, and carbonates of rare earth elements.

8 . The method for producing a ceramic scintillator according to claim 7 , wherein said rare earth compound comprises at least gadolinium oxide.

9 . The method for producing a ceramic scintillator according to claim 7 , wherein said rare earth compound comprises at least gadolinium oxide and praseodymium oxide.

10 . The method for producing a ceramic scintillator according to claim 1 , wherein when rare earth compounds of plural types of rare earth elements are added to sulfuric acid and/or sulfate in said mixing step, smaller amounts of rare earth compounds are earlier added.

11 . The method for producing a ceramic scintillator according to claim 1 , which further comprises a step of annealing said sintered body.

12 . A ceramic scintillator produced by the method recited in claim 1 .

13 . A scintillator array comprising the ceramic scintillators recited in claim 12 .

14 . A radiation detector comprising the ceramic scintillators recited in claim 12 .

Assignees

• Hitachi Metals Ltd

Inventors

• TERAZAWA Shinsuke
• Nitta Hideo

Classifications

• C01F17/294

  Oxysulfides · CPC title

• C04B2235/77

  Density · CPC title

• C04B2235/3224

  Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide · CPC title

• C04B2235/604

  Pressing at temperatures other than sintering temperatures · CPC title

• C04B35/5156

  based on rare earth compounds · CPC title