Neutron filtering system for neutron capture cross section measurement at the ANNRI beamline of MLF/J-PARC

Rovira Leveroni, G.   ; 木村 敦   ; 中村 詔司  ; 遠藤 駿典   ; 岩本 修  ; 岩本 信之  ; 片渕 竜也*; 児玉 有*; 中野 秀仁*; 堀 順一*; 芝原 雄司*; 寺田 和司*

Rovira Leveroni, G.; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Iwamoto, Osamu; Iwamoto, Nobuyuki; Katabuchi, Tatsuya*; Kodama, Yu*; Nakano, Hideto*; Hori, Junichi*; Shibahara, Yuji*; Terada, Kazushi*

A neutron filtering system has been installed at the ANNRI beamline in order to bypass the doublet structure of the incident neutron beam in the keV region. Thick cylindrical slabs of Fe, Si and Cr which share the characteristic of a sharp minimum in the neutron total cross section, were separately introduced in an intermediate stage of the beamline, before the NaI(Tl) spectrometer experimental area. The filtered neutron beams were analyzed by means of both neutron capture and transmission experiments. Moreover, further information about the neutron energy distribution within the filtered peaks was derived through the use of Monte-Carlo simulations with the PHITS code. The characteristics of the filtered neutron beams for Fe, i and Cr are presented together with Au standard experimental results to assess the performance of the neutron filtering system in neutron capture cross section experiments.