Measurements of neutron total cross-sections and resonance parameters of niobium using pulsed neutrons generated by an electron linac

Abstract

We measured neutron total cross-sections of natural niobium in the neutron energy region from 0.05 to 300 eV by using the time-of-flight method at the Pohang Neutron Facility, which consists of an electron linear accelerator, a water-cooled tantalum target with a water moderator, and a 12-m long time-of-flight path. A 6 Li-ZnS(Ag) scintillator with a diameter of 12.5 cm and a thickness of 1.6 cm was used as a neutron detector, and a high purity natural niobium metallic disc with a diameter of 8.0 cm and a thickness of 15.0 mm thickness was used for the neutron transmission measurement. Notch filters composed of Co, In, Cd were used to estimate the back- ground level and to calculate the length of neutron flight path. In order to reduce the gamma-ray background from bremsstrahlung and from neutron capture, we used a neu- tron-gamma separation system based on their different pulse shapes. The present measurement was compared with the existing experimental and the evaluated data. The res- onance parameters of 93 Nb isotope were obtained from the transmission by using the SAMMY code and were com- pared with other previous results.