Design And Performance Of A High-Pressure Xenon Gas Tpc As A Prototype For A Large-Scale Neutrinoless Double-Beta Decay Search

A high-pressure xenon gas time projection chamber, with a unique cellular readout structure based on electroluminescence, has been developed for a large-scale neutrinoless double-beta decay search. In order to evaluate the detector performance and validate its design, a 180 L size prototype is being constructed and its commissioning with partial detector has been performed. The obtained energy resolution at 4.0 bar is 1.73 +/- 0.07% (FWHM) at 511 keV. The energy resolution at the Xe-136 neutrinoless double-beta decay Q-value is estimated to be between 0.79 and 1.52% (FWHM) by extrapolation. Reconstructed event topologies show patterns peculiar to the track endpoint that can be used to distinguish 0v beta beta signals from gamma-ray backgrounds.