Lessons from Monte Carlo simulations of the performance of a dual-readout fiber calorimeter

The RD52 calorimeter uses the dual-readout principle to detect both electromagnetic and hadronic showers, as well as muons. Scintillation and Cherenkov light provide the two signals which, in combination, allow for superior hadronic performance. In this paper, we report on detailed, GEANT4 based Monte Carlo simulations of the performance of this instrument. The results of these simulations are compared in great detail to measurements that have been carried out and published by the DREAM Collaboration. This comparison makes it possible to understand subtle details of the shower development in this unusual particle detector. It also allows for predictions of the improvement in the performance that may be expected for larger detectors of this type. These studies also revealed some inadequacies in the GEANT4 simulation packages, especially for hadronic showers, but also for the Cherenkov signals from electromagnetic showers.