Development of a Simulation Framework for Spherical Proportional Counters

The spherical proportional counter is an innovative gaseous detector with numerous applications, including dark matter searches and neutron spectroscopy. We combine the simulation software toolkits Geant4 and Garfield++ to create a complete simulation framework of the detector that benefits from the strength of each toolkit. The interface is realised via the Geant4 physics parameterisation and sensitive detector features. The simulated signal properties for muons, electrons and photons are presented, as well as the effect of the gas mixture on the detector response. The simulation results are being validated with measurements from a 15 cm radius spherical proportional counter at the University of Birmingham.