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 for 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 23Na, 27Al, 51V, 55Mn, 59Co, 141Pr, 186W and 197Au were measured and the emission probabilities by this method were deduced. The experiment was performed at the super-mirror neutron guide tube at the Kyoto University Reactor. For the nucleus 24Na, 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 an uncertainty of approximately 5 per cent. (authors)