Development of the measurement technique for nuclear data with prompt gamma-ray spectroscopy

To obtain the thermal neutron capture cross sections of radioactive fission product nuclides as the basic data on transmutation study, a measurement technique with prompt gamma-ray spectroscopy was developed. When daughter nuclides after neutron irradiations are stable, measuring the neutron capture cross sections is impossible. Therefore, a new technique was developed to investigate these. With this, the level schemes from the information of the prompt γ-rays emitted during neutron irradiation are constructed, and the cross section is deduced with the emission probabilities of prompt γ-rays. The measurement system for this technique was developed, and was effective. The system enables obtaining information on the cascade γ-rays necessary for constructing the level-scheme. By measuring natPd, the partial level-scheme was constructed, and two new levels at 1906 keV and 2400 keV were identified. By using this technique, the neutron capture cross sections of nuclides that can't be measured by an activation method can be measured. (author)