A facility for measurements of (n,γ) cross-sections of a nucleus in the range 0.008≤En<20 MeV

A new measurement system to determine the neutron-capture cross-sections of a nucleus at 0.008≤En<20 MeV has been installed at the 4 MV Pelletron accelerator laboratory at the facility of radiation standards at Japan Atomic Energy Agency. The performance of the new system was studied by measuring the neutron-capture reaction cross-section of natPb using pulsed neutrons from 7Li(p,n)7Be at 12≤En≤103 keV. Prompt γ-rays from the reaction were detected by means of a highly sensitive anti-Compton NaI(Tl) spectrometer combined with a time-of-flight method. The obtained result demonstrated good sensitivity of the new system to determine the neutron-capture cross-sections of a nucleus at kiloelectron volt neutron energy.