Patent ID: 8377335

Claim:
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.