Response function for the measurement of (n,) reactions with the ANNRI-Cluster Ge detectors at J-PARC

Hara, Kaoru; Goko, Shinji*; Harada, Hideo   ; Hirose, Kentaro  ; Kimura, Atsushi   ; Kin, Tadahiro*; Kitatani, Fumito  ; Koizumi, Mitsuo ; Nakamura, Shoji  ; Toh, Yosuke   ; Igashira, Masayuki*; Katabuchi, Tatsuya*; Kino, Koichi*; Kiyanagi, Yoshiaki*; Hori, Junichi*

Recently, neutron shields of a large Ge detector array at the Accurate Neutron-Nucleus Reaction Measurement Instrument (ANNRI) in the Japan Proton Accelerator Research Complex (J-PARC) were modified to suppress the background from boron rubber sheets to enriched LiF tiles. For the new experimental set-up, efficiencies and response functions of the cluster Ge detectors with the BGO anti-coincidence detectors were measured with -rays from standard sources and prompt -rays from the Si(n,) and Cl(n,) reactions. The simulation parameters were adjusted with the EGS5 code so as to reproduce the data set of efficiencies and response functions. Based on this information, a pulse height weighting function will be deduced in the energy range of 0.1-10 MeV.