| 摘要 |
PURPOSE:To reduce background noises due to gamma-rays and to analyze a microelement with high accuracy, by applying a neutron absorbing material of boron, etc., on one counter electrode surface of 2 ionization chambers. CONSTITUTION:In order to reduce (alpha) rays incident to an ionization measuring area from materials other than a material to be measured, or a signal of a fission piece, an organic material whose uranium content is small is used for current collecting electrodes 2, 3, and its surface is covered with a metallic film 14. Also, in order to reduce background noises due to gamma-rays, a neutron absorbing material 15 of boron, etc. is applied on the counter electrode surface of one ionization chamber of 2 ionization chambers partitioned by a high voltage electrode 1. According to this constitution, the gamma-rays are sensed by both the ionization chambers, but a neutron is sensed by only one ionization chamber, therefore, a current by the gamma-rays is removed by only differentially amplifying a signal from the current collecting electrodes 2, 3, and only a current by the neutron is obtained as an output. |
