Optical simulations of the XENON1T experiment and comparison to data

The XENON Dark Matter Project uses a dual-phase xenon time projection chamber (TPC) for a direct detection of weakly interacting massive particles (WIMPs). The current operating step, XENON1T, is the most sensitive direct detection dark matter experiment in the world. Therefore, the TPC is build to detect low intensity light signals, generated directly by the recoil of incoming scattered particles (S1) or through proportional scintillation (S2) from the electrons generated in the scattering process and drifted into the xenon gas phase. The light collection efficiency (LCE) of these signals depends on the position of the interaction in the active volume and on optical properties of the materials. The resulting LCE map is used as an input parameter for waveform simulations which converts GEANT4 interactions to actual photomultiplier tube (PMT) signals that can be processed with the XENON1T data processor. A validation of the generated LCE maps with calibration data using simulations as well as the comparison of simulated and measured waveforms is shown.