AXEL Xenon gas TPC for neutrinoless double beta search: prototype performance and status of 1,000L detector construction

AXEL (A Xe ElectroLuminescence) is a project aiming to search for Neutrinoless Double Beta Decay($0nu beta beta$) of $mathrm{^{136}Xe}$, using a high-pressure gas Xe time projection chamber. The performance was demonstrated with the 180L detector; energy resolution of 0.92%(FWHM) was achieved at 1836 keV.
  Currently, construction of a 1,000L detector is on going to start the $0nu beta beta$ search. Expected sensitivity and the construction status will be reported.