PROBLEM TO BE SOLVED: To provide a radiation detector capable of acquiring a preferable energy subtraction image.SOLUTION: A radiation detector includes: a first scintillator 111； a second scintillator 112 at an opposite side to an incident side on which a radiation beam 131 is incident on the first scintillator 111； and a photo-detector 113 for converting light generated in the first scintillator 111 and the second scintillator 112 to electric signals. The radiation detector having at least one concentration configuration of a first concentration configuration in which the first scintillator 111's activator concentration in an opposite side region 111b is lower than that in an incident side region 111a and a second concentration configuration in which the second scintillator 112's activator concentration in an incident side region 112b is lower than that in an opposite side region 112a.SELECTED DRAWING: Figure 3COPYRIGHT: (C)2020,JPO&INPIT【課題】良好なエネルギーサブトラクション画像を取得することが可能な放射線検出装置を提供する。【解決手段】第１のシンチレータ１１１と、第１のシンチレータ１１１に対して放射線１３１が入射する入射側とは反対側に配置された第２のシンチレータ１１２と、第１のシンチレータ１１１及び第２のシンチレータ１１２で発生した光を電気信号に変換する光検出器１１３とを有し、第１のシンチレータ１１１における付活剤の濃度が、反対側領域１１１ｂの方が入射側領域１１１ａよりも低い第１の濃度構成、及び、第２のシンチレータ１１２における付活剤の濃度が、入射側領域１１２ｂの方が反対側領域１１１ａよりも低い第２の濃度構成のうち、少なくとも１つの濃度構成を備える。【選択図】図３
