BetaShape code

The first version of BetaShape as a new code for improved calculations of beta spectra was released during 2016. Major features of this code are improved theoretical modelling of the beta-decay process, a database of experimental shape factors, the provision of mean energies and logft-values, as well as beta and neutrino spectra, the ability to interface with ENSDF files, and the propagation of the uncertainties from the input data. This code is also used by the DDEP (Decay Data Evaluation Project) international collaboration for decay data evaluations. Developments since then have been implemented in a new version of the code. Radiative corrections have been modified from previous modelling developed in the 1970s to an accurate and modern model developed in the context of the high-precision study of super-allowed beta decays. Furthermore, the treatment of uncertainty propagation has been modified when there is a lack of uncertainty information in the input file since the previous treatment led to unrealistic values. The database of experimental shape factors has been updated for the ³⁶Cl and ¹³⁸La β^– transitions, and the ground-state-to-ground-state β⁺ transition occurring in ¹⁴O decay has been added. Following a request from various users who experienced difficulties in using the code, a specific file format for continuous data compatible with the ENSDF format has been proposed to provide recommended β spectra directly. A continuation record has also been suggested to provide the parameters of an experimental shape factor within individual ENSDF files.