Study of neutron capture reactions using the 4π ge spectrometer

The 4π Ge spectrometer composed of 22-30 Ge detectors was developed, and it has been used to study neutron capture reactions with a neutron time-of-flight (TOF) technique. Since the distances between the sample position and the Ge detectors are variable, it can be used as a multifunctional spectrometer. At first, it was used as a sum energy spectrometer, and resonances in ^natAg were identified as those of ¹⁰⁷Ag or ¹⁰⁹Ag. In second, it was used to deduce γ-ray intensity distribution for each resonance, and the results for ²³⁸U were presented. In third, it was used to measure neutron capture cross sections of minor actinides and fission products at the electron linear accerelator facility of KURRI and at the accurate neutron-nucleus reaction measurement instrument (ANNRI) in MLF of J-PARC. The preliminary results are discussed mainly based on measurements of neutron capture cross section for ²⁴¹Am, together with related techniques.