Photonuclear reaction cross section of Sm

Hara, Kaoru; Harada, Hideo   ; Kitatani, Fumito  ; Goko, Shinji*; Hohara, Shinya*; Kaihori, Takeshi*; Makinaga, Ayano*; Utsunomiya, Hiroaki*; Toyokawa, Hiroyuki*; Yamada, Kawakatsu*; Watanabe, Yukinobu*

Neutron capture cross sections of the unstable nuclei Sm (t=90yr) are the fundamental data for the nuclear transmutation, since the Sm is one of radioactive fission products in the nuclear waste. On the other hand, the branching point nucleus Sm is important for characterizing the slow neutron capture process (s-process) nucleosynthesis in the AGB stars. The cross sections of the inverse Sm(,n)Sm reaction were measured with the laser-Compton scattering (LCS) rays at 8.3-12.4 MeV. Quasi-monochromatic beams of LCS photons irradiated an enriched SmO sample. The emitted neutrons were detected with a 4 neutron detector consisting of 20 He proportional counters embedded in a polyethylene moderator. The Au(,n) reaction cross sections were also measured as a standard. In the data analysis, the (,n) cross sections are deduced with two methods. The present data for Sm and Au are compared with the previous data compiled in the IAEA document and the calculation with a nuclear reaction code TALYS. The neutron capture cross sections for Sm in the keV-MeV energy range are evaluated with the present photonuclear data for Sm as constraint in the statistical model calculations.