Benefits of the Use of Monte Carlo Simulations in Cryogenic Detector Design

Monte Carlo simulations represent a useful tool to predict and understand the behavior of X-ray detectors in space and on ground. We made use of the Geant4 software to simulate the performances of several TES detectors. We investigated the performances of the X-IFU CryoAC, a large area TES-based silicon detector in a laboratory environment, and its response to the ground level flux of cosmic muons. We were able to predict the background of the Athena X-IFU instrument (ESA) in the L1 environment for an equivalent time of \(\sim\)100 ks and used the code to investigate the dependence of such a background on possible changes in the geometry such as pixel layout and size. We also compared the results with the ones obtained for the Line Emission Mapper (LEM), a probe concept proposed to NASA that uses a different TES array optimized for higher spectral resolution of lower energy photons, identifying issues with the detector design and indicating possible solutions.