Radiation detector

A plurality of insulators are inserted and longitudinally spaced within a long cylindrical outer electrode the inner face of which is coated with a fissible material. A center electrode rod, slidably inserted into the outer electrode through the insulators to form a plurality of ionization chambers defined between insulators, is connected to the center core of a cable while the outer electrode is connected to the outer conductor of this cable, said center core and outer conductor being connected to a current meter. The ionization current in each chamber is obtained from Isub(i)-Isub(i-1) where Isub(i) and Isub(i-1) are total ionization currents measured when the top of the center electrode reaches the i-th and i-1-th chambers numbered respectively, from the cable side. (Ohno, Y.)