Bonner spheres calibration in quasi-mono-energetic high-energy neutron sources

Mares, V.*; Pioch, C.*; Iwamoto, Yosuke   ; Hagiwara, Masayuki*; Hatanaka, Kichiji*; Iwase, Hiroshi*; Masuda, Akihiko*; Matsumoto, Tetsuro*; Rhm, W.*; Shima, Tatsushi*; Tamii, Atsushi*; Yashima, Hiroshi*; Nakamura, Takashi*

Calibration measurements for a Bonner sphere spectrometer (BSS) with He proportional counter were performed in quasi-mono-energetic neutron fields at the Research Center for Nuclear Physics (RCNP) at the University of Osaka, Japan. Neutrons with nominal peak energies of 134 MeV and 197 MeV were generated in lithium target. The neutron spectra were determined by BSS measurements in the range from peak energy down to thermal energies using the MSANDB unfolding code. Three different sets of response functions calculated by Monte Carlo codes GEANT4 and MCNP/LAHET were used. For calibration of the BSS, the remaining count rates resulting from neutrons E 10 MeV were compared to calculated count rates using the independently measured TOF spectra and the response functions of the Bonner spheres. Within the uncertainties involved in the experiment a remarkable overall agreement of the measurements and response calculations was observed.