Study of fission modes in Md with six-dimensional Langevin equation

6次元Langevin方程式を用いたMd核分裂モードの研究

岡田 和記; 西尾 勝久   ; 和田 隆宏*; Carjan, N.*

Okada, Kazuki; Nishio, Katsuhisa; Wada, Takahiro*; Carjan, N.*

We calculate the fission process of Md with the multi-dimensional Langevin equation with the Cassini shape parameterization. To describe various fission modes, we use the six Cassini shape parameters , and apply them to the six-dimensional Langevin equation. The combination of these shape parameters can flexibly describe deformed nuclear shapes. This is the first attempt to calculate the Langevin dynamics in the six-dimensional collective coordinates. The resulting fragment mass and TKE distributions show the existence of three types of fission modes, consistent with the measurement data from JAEA. Furthermore, by increasing the excitation energy from 15 MeV to 18 MeV, the relative contribution of each mode is changed. With higher excitation energy, the short symmetric fission mode decreases significantly, and the asymmetric fission mode becomes dominant. It is considered that the shell effect corresponding to short symmetric fission is largely damped by the increase in excitation energy. Through analysis of fission paths obtained from these six-dimensional Langevin calculations, we expect to elucidate the physical origins and mechanisms of each fission mode.