Fission Reaction Event Yield Algorithm FREYA 2.0.2

FREYA (Fission Reaction Event Yield Algorithm) is a fission event generator which models complete fission events. As such, it automatically includes fluctuations as well as correlations between observables, resulting from conservation of energy and momentum. The purpose of this paper is to present the main differences between FREYA versions 1.0 and 2.0.2 : additional fissionable isotopes, angular momentum conservation, Giant Dipole Resonance form factor for the statistical emission of photons, improved treatment of fission photon emission using RIPL database, and dependence on the incident neutron direction. FREYA 2.0.2 has been integrated into the LLNL Fission Library 2.0.2, which has itself been integrated into MCNP6.2, TRIPOLI-4.10, and can be called from Geant4.10. The previous version of this program (AEVS_v1_0) may be found at http://dx.doi.org/10.1016/j.cpc.2015.02.002.FREYA（裂变反应事件产额算法，Fission Reaction Event Yield Algorithm）是一款用于模拟完整裂变事件的裂变事件生成器。正因如此，该工具会自动纳入由能量与动量守恒定律所引发的可观测量涨落与关联特性。本文旨在阐述FREYA 1.0与2.0.2两个版本间的主要差异：新增可裂变同位素、引入角动量守恒规则、适配光子统计发射的巨偶极共振 (Giant Dipole Resonance) 形状因子、采用RIPL数据库（参考输入参数库，Reference Input Parameter Library）优化裂变光子发射的处理流程，以及对入射中子方向的依赖性。FREYA 2.0.2已集成至LLNL裂变库2.0.2中，而该裂变库又进一步集成至MCNP6.2、TRIPOLI-4.10，同时可在Geant4.10环境中调用。该程序的旧版本（AEVS_v1_0）可通过链接http://dx.doi.org/10.1016/j.cpc.2015.02.002获取。