RAINIER: A Simulation Tool for Distributions of Excited Nuclear States and Cascade Fluctuations

Abstract

A new code has been developed named RAINIER that simulates the $\gamma$-ray decay of discrete and quasi-continuum nuclear levels for a user-specified range of energy, angular momentum, and parity including a realistic treatment of level spacing and transition width fluctuations. A similar program, DICEBOX, uses the Monte Carlo method to simulate level and width fluctuations but is restricted to $\gamma$-ray decay from no more than two initial states such as de-excitation following thermal neutron capture. On the other hand, modern reaction codes such as TALYS and EMPIRE populate a wide range of states in the residual nucleus prior to $\gamma$-ray decay, but do not go beyond the use of deterministic functions and therefore neglect cascade fluctuations. This combination of capabilities allows RAINIER to be used to determine quasi-continuum properties through comparison with experimental data. Several examples are given that demonstrate how cascade fluctuations influence experimental high-resolution $\gamma$-ray spectra from reactions that populate a wide range of initial states.

14 pages, 13 figures, Nuclear Instrumentation and Methods A, 2017

References in corpus (6)

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• Power-law intensity distribution in $\gamma$-decay cascades -- Nuclear Structure as a Scale-Free Random Network
• Constraining the Synthesis of the Lightest p Nucleus 74Se
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