A negative-ion TPC with ultra-high energy resolution for 0-ν double beta decay search in 136Xe

Abstract

Future searches for the neutrino-less double beta decay mode in candidate nuclei must confront the need for sensitivities at the level of 10 – 50 meV effective neutrino mass. Current techniques may not be able to scale simultaneously to the needed mass of active isotope with both improved energy resolution and much higher levels of background rejection. To address these severe challenges, a novel approach based on a negative-ion time projection chamber filled primarily with high-pressure 136Xe gas is developed. In addition to the provision of a nearly ideal active fiducial boundary surface, an energy resolution of ∼5 × 103 FWHM appears possible at the Q-value of 2.48 MeV. The background rejection advantages of detailed track information and a single monolithic detector are addressed. A barium daughter-tagging scheme based on mobility differences and a new approach addressing the goal of efficient electron capture and release in high-density gas exploiting chemical reactions are introduced. Many R&D issues are suggested by this new concept.