Patent ID: 7282161

Claim:
An inorganic scintillator including a matrix material comprising a metal oxide, and a luminescence center made of Ce contained in the matrix material, the inorganic scintillator being adapted to scintillate in response to a radiation; wherein the matrix material further comprises a dopant having a tetravalent ionization energy I [kJ·mol −1 ] satisfying the condition represented by the following expression (1): 3000≦I≦3500 (1); wherein the dopant content n 1 [mol] and the content n 2 [mol] of the luminescence center (Ce) satisfy the condition represented by the following expression (2): 0.0001≦( n 1 /n 2)≦0.1 (2); wherein the scintillator is a single crystal; wherein the dopant is Hf; wherein the matrix material has a chemical composition represented by the following general formula (3) and simultaneously satisfies the conditions represented by the following expressions (4) to (6): Ln 2x Si y O (3x+2y) (3) 0.9≦x≦1.1 (4) 0.9≦y≦2.1 (5) 4.5≦(3 x+ 2 y )≦7.5 (6) where Ln is at least one species of element selected from the group consisting of elements belonging to rare-earth elements, and x and y are values each simultaneously satisfying the conditions represented by expressions (3) to (6); and wherein the matrix material has a chemical composition represented by the following formula (7): Gd 2 SiO 5 (7).