Photoneutron emission process on nuclei around A = 200 for giant dipole resonance energies based on neutron energy and angular distribution

中性子エネルギー及び角度分布に基づく巨大双極子共鳴エネルギーに対する質量数200近傍の原子核からの光中性子放出過程

Nguyen, T. H. T.; 佐波 俊哉*; 山崎 寛仁*; 岩本 信之  ; 糸賀 俊朗*; 桐原 陽一  ; Lee, E.*; 杉原 健太*; 宮本 修治*; 橋本 智*; 浅野 芳裕*

Nguyen, T. H. T.; Sanami, Toshiya*; Yamazaki, Hirohito*; Iwamoto, Nobuyuki; Itoga, Toshiro*; Kirihara, Yoichi; Lee, E.*; Sugihara, Kenta*; Miyamoto, Shuji*; Hashimoto, Satoshi*; Asano, Yoshihiro*

This study has concentrated on the angular distribution of photoneutron emission on Ta, W, Au, Pb, and Bi for a 12.6 MeV linearly polarized photon beam. The angular distribution was obtained from the double differential cross-sections (DDXs), measured at the NewSUBARU-BL01 facility, and can be expressed as a function of azimuthal angle. The DDXs were divided into two distinct components based on the angular coefficient ratio: the low-energy component up to 3 MeV and the high-energy above 3 MeV. The angular distribution of the low-energy component was isotropic, whereas the high-energy component was distributed anisotropically and depended on the nuclear structure of target nuclei. The anisotropy is apparent on the spherical nuclei, but minor on the deformed ones. The comparison of angular coefficient ratios for 12.6 MeV and 16.6 MeV photon energies in the previous studies emphasized the correlation between photoneutron emission and nuclear structure.