radioactivedecay: A Python package for radioactive decay calculations

Abstract

radioactivedecay is a Python package for radioactive decay modelling. It contains functions to fetch decay data, define inventories of nuclides and perform decay calculations. The default nuclear decay dataset supplied with radioactivedecay is based on ICRP Publication 107, which covers 1252 radioisotopes of 97 elements. The code calculates an analytical solution to a matrix form of the decay chain differential equations using double or higher precision numerical operations. There are visualization functions for drawing decay chain diagrams and plotting activity decay curves. Statement of Need Calculations for the decay of radioactivity and the ingrowth of progeny underpin the use of radioisotopes in a wide range of research and industrial fields, spanning from nuclear engineering, medical physics, radiation protection, environmental science and archaeology to non-destructive testing, mineral prospecting, food preservation, homeland security and defence. radioactivedecay is an open source, cross-platform package for decay calculations and visualization. It supports decay chains with branching decays and metastable nuclear isomers. It includes a high numerical precision decay calculation mode, which resolves numerical problems with using double-precision floating-point numbers to calculate decay chains involving radionuclides with disparate half-lives (Bakin et al., 2018). This set of features distinguishes radioactivedecay from other commonly-used decay packages, such as Radiological Toolbox (Hertel et al., 2015) and PyNE (Scopatz et al., 2012). Radi ological Toolbox is a closed-source Windows application, so it is not easily scriptable and its use of double-precision arithmetic makes it susceptible to numerical round-off errors. PyNE uses approximations to help mitigate numerical issues, however these may potentially affect accuracy. Moreover as of v0.7.5, PyNE does not correctly model metastable nuclear isomers within decay chains, which means, for example, it cannot simulate the production of 99m Tc from 99 Mo for medical imaging applications.