Managing Geant4 simulations with Nextflow

This presentation illustrates how to use the scientific workflow manager Nextflow to manage a particle physics simulation and analysis pipeline based on Geant4 and ROOT in a high-performance computing (HPC) environment. The example shown simulates background spectra arising from the presence of the radionuclides ²³⁸U and ²³⁴Th in the CaWO₄ target crystal of the TUM40 detector module of the CRESST experiment, which searches for dark matter. Using a scientific workflow manager reduces the risk of human error and improves the reproducibility and traceability of the simulated datasets. This is particularly important in the case of lazy parallelism, that is, when the same simulation is run several times in parallel to increase the volume of simulated data.