Thermoluminescent dating and its application to gamma ray dosimetry

Tiles and bricks from buildings remaining since the time of the bomb were collected as samples for the evaluation of gamma ray dose from two points within 1000 m from the hypocenter and five points 1000-2000 m from the hypocenter. Samples were also collected for the evaluation of background radiation from three points more than 2000 m from the hypocenter. As two buildings of Hiroshima University Faculty of Science which were exposed to the bomb still remain, tiles could be systematically collected at intervals of 180 m between 1259 m and 1439 m from the hypocenter. In addition, iron material with 60Co activity, and rocks and concrete blocks with 151Eu activity, were collected from eight points for evaluating the neutron dose and samples were also collected from which data on the variation of the thermal neutron fluence in water can be obtained. (author)