Neutron capture cross section measurements on ²³²Th with a total absorption BGO spectrometer at KURRI-LINAC

We have measured the neutron capture cross section of ²³²Th by the neutron time-of-flight (TOF) method in the energy range from 1 eV to 800 eV using a 46-MeV electron linear accelerator (linac) at the Research Reactor Institute, Kyoto University (KURRI). An assembly of 12 pieces of Bi₄Ge₃O₁₂ (BGO) scintillators, which was placed at a distance of 12.7 m from the neutron source, was employed as a total energy absorption detector for neutron capture gamma-ray measurement. The incident neutron flux was determined with the ¹⁰B(n,αγ) standard reaction and the relative capture cross sections of ²³²Th were normalized to the evaluated values of JENDL-4.0 at the 21.8-eV resonance. This paper presents preliminary results. (author)