概要
The non vanishing neutrino mass is so far the only direct evidence of physics beyond the standard model.
Dark Matter (DM) and 0ν Double Beta Decay (DBD) are additional phenomena predicted by theory.
For both massive, well shielded xenon detectors seem ideal.
For DBD a high pressure gaseous detector is more promising than the liquid xenon approach of DM.
PandaX III is under design for DBD search in the enlarged JinPing lab in Szechuan Province, China.
Originally the detector will have 200 kg of 80 % enriched 136Xe, but can be expanded to 1 ton in the future.
The read out with μBulk μMegas will provide images with < 3 mm position resolution.
This will allow to additionally discriminate background by reconstruction the two 10 cm long, back-to-back electron tracks.
The better good energy resolution will result in an excellent background rejection capability and should push the 0ν DBD limit beyond 10^{26} yrs.
The additional topological background rejection should provide a nearly 'background free' experiment.
Initial tests with small prototypes have started already, and the detector is supposed to be operational underground in the new JinPing lab within 2 years.