Solid scintillator, radiation detector, and tomograph
A solid scintillator having short afterglow and high output, containing a polycrystal containing a crystal of a Gd garnet structure oxide having a composition ratio of formula (1): (M 1-x-y Gd x Q y ) 3 J 5 O 12 (1) where M is at least one element of La and Tb, Q is at least one element of Ce and Pr, J is at least one element selected from Al, Ga, and In, x and y satisfy the relations 0.5≦x<1, and 0.000001≦y≦0.2, and further containing Si and fluorine, where the solid scintillator contains 1 ppm by mass to 1000 ppm by mass of the Si with respect to the Gd garnet structure oxide, and 1 ppm by mass to 100 ppm by mass of the fluorine with respect to the Gd garnet structure oxide. In addition a radiation detector and a tomograph employing the solid scintillator.
1. A solid scintillator comprising a polycrystal, the polycrystal comprising a crystal of a Gd garnet structure oxide having a composition ratio of formula (1):
(M 1-x-y Gd x Q y ) 3 J 5 O 12 (1),
M, where present, is at least one element selected from the group consisting of La and Tb;
Q is at least one element selected from the group consisting of Ce and Pr;
J is at least one element selected from the group consisting of Al, Ga, and In;
x and y satisfy relations 0.5≦x<1 and 0.000001≦y≦0.2;
the polycrystal further comprises 1 ppm by mass to 1000 ppm by mass of Si with respect to the Gd garnet structure oxide, and 4 ppm by mass to 87 ppm by mass of fluorine with respect to the Gd garnet structure oxide.
2. A radiation detector, comprising the solid scintillator of claim 1 .
3. A tomograph, comprising the radiation detector of claim 2 .
4. The solid scintillator of claim 1 , wherein M is present and M of formula 1 comprises La.
5. The solid scintillator of claim 1 , wherein M is present and M of formula 1 comprises Tb.
6. The solid scintillator of claim 1 , wherein Q of formula 1 comprises Ce.
7. The solid scintillator of claim 1 , wherein Q of formula 1 comprises Pr.
8. The solid scintillator of claim 1 , wherein J of formula 1 comprises Al.
9. The solid scintillator of claim 1 , wherein J of formula 1 comprises Ga.
10. The solid scintillator of claim 1 , wherein J of formula 1 comprises In.
11. The solid scintillator of claim 1 , wherein Q is Ce, and J is Al.
12. The solid scintillator of claim 1 , wherein Q is Ce, and J is a mixture of Al and Ga.
13. The solid scintillator of claim 1 ,
wherein M is present,
M is Tb,
Q is Ce, and
J is Al.
14. The solid scintillator of claim 1 ,
wherein M is present,
M is La,
Q is Ce, and
J is a mixture of Al and Ga.
15. The solid scintillator of claim 11 ,
wherein M is absent,
x is 0.99, and
y is 0.01.
16. The solid scintillator of claim 12 ,
wherein M is absent,
x is 0.99, and
y is 0.01.
17. The solid scintillator of claim 12 ,
wherein M is absent,
x is 0.95, and
y is 0.05.
18. The solid scintillator of claim 13 ,
wherein M is present,
x is 0.5, and
y is 0.1.
19. The solid scintillator of claim 14 ,
wherein M is present,
x is 0.5, and
y is 0.05.
20. The solid scintillator of claim 1 , wherein M is present and 1-x-y>0.