An object of the present invention is to provide a solid scintillator having short afterglow and high output, and a radiation detector and a tomograph using the solid scintillator. The opposing side of the electrode layer 630 includes a backing layer 640 of a material with a thermal expansion coefficient approximately equal to the thermal expansion coefficient of the electrolyte layer 620. The material may also include an isoalkoxy amine oxide and a glycol ether.