Validation of pulse shape simulation for GERDA Phase II prototype detectors

The GERDA (GERmanium Detector Array) Experiment is designed to search for the neutrinoless double beta (0νββ) decay of 76Ge. The 0νββ decay events have two electrons in the final state which deposit their energy predominantly locally, hence are called single-site events. Most of the background events deposit their energy at several different positions inside the detector, hence are called multi-site events. It has been shown that the 18-fold segmented germanium detector designed for GERDA Phase II is quite capable to distinguish between single- and multi- site events. Pulse shape analysis based on signals from the prototype detector has also been carried out recently to further improve the discrimination power. A pulse shape simulation package has been developed to estimate the efficiency of the analysis. The simulation has been compared to different sets of data taken from several GERDA Phase II prototype detectors. It shows that the effects from the crystal structure on the drift of charge carriers can be properly simulated.