SEMICONDUCTOR GAMMA, X RAYS DETECTOR

PURPOSE:To bring the counting rate of gamma ray close to a fixed level depending on no energy incidence irradiation beam by laminating detection elements through an absorbing material. CONSTITUTION:Silicon detection elements 1, 3 and 5 of a P-N junction, silicon detection elements 2 and 4 opposite in the P-N junction and the like are laminated through a semi-circle layer 7 mainly composed of lead as gamma ray absorbing material. A semi-circle layer 8, an electrode 9 and the like an provided on the elements 1 and 5 respectively. Therefore, when the energy of the incidence gamma ray 10 is small, the output is produced only from the element 1 or the like close to the incidence side. As the irradiation energy becomes small, the counting rate of gamma ray lowers while when it becomes large, the rate increases and comes closer to a fixed level depending on no energy of the incidence irradiation beam. It is the same with the X rays. Thus, a semiconductor gamma, X rays detector with a high reliability and a long life is obtained which is effectively usable for measuring irradiatin dose in the management of exposure or the like.