Scintillator, scintillator array, radiation detector, and radiation inspection device

1. A scintillator, comprising;

a sintered body having a volume of 1 mm 3 or less, the sintered body including

crystal grains having a crystal region of a rare earth oxysulfide, wherein the rare earth oxysulfide is represented by a general formula (Gd 1-a-b Pr a M b ) 2 O 2 S, wherein M is at least one element selected from the group consisting of Ce, Yb, Eu, and Tb, a is a number satisfying 0.0001≤a≤0.01, and b is a number satisfying 0≤b≤0.005, wherein an average diameter of the crystal grains is 5 μm or more and 30 μm or less, and wherein a maximum diameter of the crystal grains is 50 μm or less, and

a grain boundary disposed between the crystal grains and having a polycrystal region of polycrystal bodies, wherein each polycrystal body has a different composition from a composition of the rare earth oxysulfide, and wherein each polycrystal body contains iron and phosphorous,

wherein the number of the polycrystal bodies is 200 or less per a unit area of 100 μm×100 μm of a cross section of the sintered body.

2. The scintillator according to claim 1 , wherein in an observation image of the cross section by a scanning electron microscope, a contrast of the polycrystal region is different from that of the crystal region, and a color of the polycrystal region is deeper and darker than that of the crystal region, and

wherein an area of the polycrystal region is 10000 μm 2 or less per a unit area of 500 μm×500 μm of the cross section.

3. The scintillator according to claim 1 , wherein each polycrystal body further contains at least one element selected from the group consisting of a carbonate, iron, aluminum, phosphorous, an alkali metal element, and an alkaline earth metal element.

4. A scintillator array comprising:

a first scintillator;

a second scintillator; and

a reflective layer between the first and second scintillators,

wherein each of the first and second scintillators is the scintillator according to claim 1 .

5. The scintillator array according to claim 4 , wherein the reflective layer contains a titanium oxide or an aluminum oxide.

6. The scintillator array according to claim 4 , wherein a width between the first and second scintillators in the reflective layer is 100 μm or less.

7. A radiation detector comprising the scintillator array according to claim 4 .

8. A radiation inspection device comprising the radiation detector according to claim 7 .

9. A scintillator, comprising:

a sintered body having a volume of 1 mm 3 or less, the sintered body including

crystal grains having a crystal region of a rare earth oxysulfide, wherein the rare earth oxysulfide is represented by a general formula ((Gd 1-α X α ) 1-a-b Pr a M b ) 2 O 2 S, wherein X is at least one element selected from the group consisting of Y, La, and Lu, M is at least one element selected from the group consisting of Ce, Yb, Eu, and Tb, α is a number satisfying 0<α<1, a is a number satisfying 0.0001≤a≤0.01, and b is a number satisfying 0≤b≤0.005, wherein an average diameter of the crystal grains is 5 μm or more and 30 μm or less, and wherein a maximum diameter of the crystal grains is 50 μm or less, and

a grain boundary disposed between the crystal grains and having a polycrystal region of polycrystal bodies, wherein each polycrystal body has a different composition from a composition of the rare earth oxysulfide, and wherein each polycrystal body contains iron and phosphorous,

wherein the number of the polycrystal bodies is 200 or less per a unit area of 100 μm×100 μm of a cross section of the sintered body.