Title: Ternary fission within the temperature dependent relativistic mean field approach Show Chinese title

Title: 温度相关的相对论平均场方法中的三裂变

Abstract: For the first time, we apply the temperature dependent relativistic mean field (TRMF) model to study the ternary fission of heavy nucleus using level density approach. The probability of yields of a particular fragment is obtained by evaluating the convolution integrals which employ the excitation energy and the level density parameter for a given temperature calculated within the TRMF formalism. To illustrate, we have considered the ternary fissions in 252Cf, 242Pu and 236U with fixed third fragment A3 = 48Ca, 20O and 16O respectively. The relative yields are studied for the temperatures T = 1, 2 and 3 MeV. For the comparison, the relative yields are also calculated from the single particle energies of the finite range droplet model (FRDM). In general, the larger phase space for the ternary fragmentation is observed indicating that such fragmentations are most probable ones. For T = 2 and 3 MeV, the Sn + Ni + Ca is the most probable combination for the nucleus 252Cf. However, for the nuclei 242Pu and 236U, the maximum fragmentation yields at T = 2 MeV differ from those at T = 3 MeV. For T = 3 MeV, the closed shell (Z = 8) light mass fragments with its corresponding partners has larger yield values. But, at T = 2 MeV Si/P/S are favorable fragments with the corresponding partners. It is noticed that the symmetric binary fragmentation along with the fixed third fragment for 242Pu and 236U are also favored at T = 1 MeV. The temperature dependence of the nuclear shape and the single particle energies are also discussed. Show Chinese abstract

Abstract: 我们首次应用温度相关的相对论平均场（TRMF）模型，利用能级密度方法研究重核的三裂变现象。 通过计算卷积积分获得特定碎片产额的概率，该积分使用了根据TRMF形式主义在给定温度下计算出的激发能和能级密度参数。 为了说明这一点，我们考虑了固定第三个碎片A3分别为48Ca、20O和16O的252Cf、242Pu和236U的三裂变情况。 对于温度T=1、2和3 MeV时的相对产额进行了研究。 为了比较，还从有限范围液滴模型（FRDM）的单粒子能量计算了相对产额。 通常情况下，观察到三裂变的更大相空间，这表明这种裂变是最有可能发生的。 对于T=2和3 MeV，Sn+Ni+Ca是252Cf核最可能的组合。 然而，对于242Pu和236U核，在T=2 MeV时的最大裂变产额与T=3 MeV时不同。 对于T=3 MeV，具有相应伙伴的闭壳轻质量碎片有更大的产额值。 但在T=2 MeV时，Si/P/S及其相应的伙伴是更优的选择。 注意到在T=1 MeV时，242Pu和236U的二元对称裂变以及固定的第三个碎片也是有利的。 讨论了核形状和单粒子能量随温度的变化。