PROBLEM TO BE SOLVED: To provide a mechanism for efficiently absorbing a shock in a small space in a housing when protecting a radiation detector housed in the housing from the shock. A buffer material 150 supports a side wall portion 103 that is coupled to an incident surface (first surface) located on a side of a housing 160 on which radiation R is incident and a rear surface (second surface) 102 opposite to the incident surface (first surface). The support base 120 is disposed between the base 120 and the support base 120. The support base 120 is provided with a convex portion 121 protruding in the direction toward the back surface 102. A convex portion 163 that protrudes in the direction is provided, and the distance between the cushioning material 150 and the support base 120 is a distance X, and the convex portion 121 of the support base 120 and the convex portion 163 of the housing 160 are provided. When the distance between them is Y, the distance X<；the distance Y. [Selection diagram] Figure 1【課題】筐体の内部に収納された放射線検出器を衝撃から保護する際に、筐体内の小空間の中で効率よくその衝撃を緩和させる仕組みを提供する。【解決手段】緩衝材１５０は、筐体１６０において放射線Ｒが入射する側に位置する入射面（第１面）及びその反対側の背面（第２面）１０２と結合する側壁部１０３と、支持基台１２０との間に配置されており、支持基台１２０には、背面１０２に向かう方向に突出した凸部１２１が設けられており、筐体１６０には、背面１０２から支持基台１２０に向かう方向に突出した凸部１６３が設けられており、緩衝材１５０と支持基台１２０との間の距離を距離Ｘとし、支持基台１２０の凸部１２１と筐体１６０の凸部１６３との間の距離を距離Ｙとすると、距離Ｘ＜距離Ｙである。【選択図】図１
