FaNGaS : A new instrument for ( n,n ′ γ ) reaction measurements at FRM II

Abstract The FaNGaS instrument was set up at the research reactor FRM II, Garching. It performs measurements of ( n,n ′ γ ) reactions based on the γ-ray spectroscopy technique within the fission neutrons energy region. The optimization studies of the experimental setup were carried out using MCNP simulations. A full characterization of the detector system and the neutron beam is presented. The determination of the neutron energy spectrum was done using the foil activation method. An average neutron energy of about 2 MeV and a neutron flux of 10 8 cm − 2 · s − 1 were measured.