Study for s-process using neutron beam provided from ANNRI of J-PARC

Hayakawa, Takehito; Toh, Yosuke   ; Kimura, Atsushi   ; Nakamura, Shoji  ; Shizuma, Toshiyuki; Harada, Hideo   

Many isotopes heavier than iron are synthesized by the slow neutron capture reaction process (s-process) in stars. Isomers in stable isotopes have sometimes an important role as a branching point. An isomer with a half-life of 14.1 y in Cd is a branching point from which a nucleosynthesis flow reaches to a rare isotope Sn. The astrophysical origin of Sn has remained still an open question. The s-process abundance of Sn depends on the ratio of the Cd(n, )Cdm reaction cross section to the Cd(n, )Cd reaction cross section. However, the isomer production ratio has not been measured in the energy region higher than the thermal energy. We measured -rays using the HPGe detectors with neutrons at ANNRI.