Measurement of neutronic characteristics of JSNS

Harada, Masahide   ; Oikawa, Kenichi   ; Maekawa, Fujio  ; Meigo, Shinichiro   ; Futakawa, Masatoshi  ; Watanabe, Noboru*

To validate the neutronics design of JSNS, we measured neutron spectra at all available neutron beam lines by CTOF method. Measured values were in good agreement with evaluated ones for beam lines without guide tubes. Some discrepancies in spectral intensity were found in some of beam lines using a neutron guide tube. This result indicates that the CTOF method is very effective for checking initial installation of beam lines because neutron spectral intensity can be measured systematically in a short time. Furthermore, by measuring neutron spectral intensity with the CTOF method, we studied change of neutronic performance due to changes of operation conditions of JSNS such as incident proton beam conditions (position, profile and energy) and moderator temperature. These operation parameter dependences on neutronic performance were compared with calculated ones, and confirmed good agreements between them. This indicated reliability of neutronics design of JSNS.