RULES: Free desktop application to perform activity calculations and radiometric dating

Calculation of activities and radiometric dating through radioactive series may lead to long or non-explicit mathematical expressions. Thus, dedicated software is required to help solve related questions. RULES (RaPCUBES, URADS and LEADS Encompassed Software) is a new computer application dedicated to calculating activities and populations for radionuclides that belong to the four radioactive series (²³⁸U, ²³⁵U, ²³²Th and ²³⁷Np) and performing dating estimations using methods based on disequilibria between isotopes within the ²³⁸U family. RULES contains three different tools. RULES has been programmed in the environment of MATLAB's AppDesigner (v. 2021b), with a database built in Microsoft Excel. It is available as completely free software via e-mail request and Manuel Martínez Rojas' profile at idUS (Research Repository of the University of Seville). Only the 9.11 version of MATLAB's Runtime is required. This does not need MATLAB's license to operate and makes the installation process straightforward through a unique link. Also, as a desktop application, RULES is able to work offline. RULES's main purpose is to provide simple-to-use software that encompasses three different tools of interest with intuitive user interfaces, so no programming knowledge is required to use the application. Also, novel revised propagation of uncertainties is implemented at all levels of the calculation processes. Furthermore, it has been demonstrated that RULES performs satisfactorily when used in actual high-quality research works. Discrepancies in results between RULES and some widespread similar software do not exceed 4% and the implemented propagation of uncertainties seems more conservative than that of the other tools. Finally, thanks to its simplicity and results visualization possibilities, RULES stands out as a useful educational instrument to study radioactive series, secular and transient equilibrium and some radiometric dating strategies.