TROPIC: A New Code for Calculating Absolute Transition Probabilities Using Python and Mathematica*

Absolute transition probabilities serve as a cornerstone for nuclear structure studies, by providing a measure of the collectivity of a particular transition and the matrix elements that connect the states of interest. We have developed Python and Mathematica versions of a program, named TROPIC (Transition Probability Calculator), for calculating absolute transition probabilities. Both versions take quantities such as the lifetime of a state, energy and intensity of the emitted γ-ray, and multipolarities of transitions to calculate B(σλ) values. TROPIC allows for the inclusion of mixing ratios of different multipolarities and the electron conversion of γ-rays, and provides results in e²b^λ or results normalized to W.u. We have tested this code against TRANSNUCLEAR [1], and will present transition probabilities calculated for ¹⁵⁶Gd using data from GRID measurements and for ¹⁵⁸Gd using data from an (n,n′γ) reaction as a comparison. Both versions, along with sample input and output files and user guides, will be available for download on the University of Notre Dame’s Nuclear Science Laboratory webpage.