Development of a determination method of the prompt γ-ray emission probability for the measurement of neutron capture cross sections

We propose a promising method of the determination of the emission probabilities by normalizing the sum of the relative intensities of the γ-rays populating the ground state. The prompt γ-rays from thermal-neutron capture in 23 Na, 27 Al, 51 V, 55 Mn, 59 Co, 141 Pr, 186 Wa nd 197 Au were measured and the emission probabilities by this method were deduced. The experiment was performed at the supermirror neutron guide tube at the Kyoto University Reactor. For the nucleus 24 Na, the emission probabilities were deduced and they were in agreement with the values, which were deduced by using the γ-rays following the β-decay, within the uncertainties of approximately 5%.