An Estimation of the fast-neutron fluence for the Hiroshima atomic bomb

Shibata, Tokushi

An estimation of the fast neutron fluence for the Hiroshima Atomic Bomb was carried out. The method is to estimate the fluence using the amount of the Ni contents in copper samples, neutron spectrum for the Hiroshima Atomic Bomb, and the excitation function of the Cu(n, p) Ni reaction. The extraction method of the trace amount of the Ni from copper samples was developed. The Ni was measured by a low-background liquid-scintillation counter. The excitation function of the Cu(n,p) Ni reaction was measured. The fluence was obtained from the measured Ni amount using the neutron spectrum and the excitation function of the reaction. The obtained results are consistent with the values given by the new dosimetry system D02.