Electroluminescence collection cell as a readout for a high energy resolution Xenon gas TPC

AXEL is a high pressure xenon gas TPC detector being developed for neutrinoless double-beta decay search. We use the proportional scintillation mode with a new electroluminescence light detection system to achieve high energy resolution in a large detector. The detector also has tracking capabilities, which enable significant background rejection. To demonstrate our detection technique, we constructed a 10L prototype detector filled with up to 10bar xenon gas. The FWHM energy resolution obtained by the prototype detector with 4 bar Xenon gas is 4.0±0.30 % at 122keV, which corresponds to 0.9∼2.0% when extrapolated to the Q value of the 0νββ decay of 136Xe.