NEXT: Neutrino Experiment with high pressure Xenon gas TPC

The search of the neutrinoless double-� decay address the major Physics goals of revealing the nature of the neutrino and setting an absolute scalefor its mass. The observation of a positive �� 0� signal, the unique signature of Majorananeutrinos, would have deep consequences in particle physicsand cosmology. Therefore, any claim of observing a positive signal shall require extremely robust evidences. NEXT is a new double-� experiment which aims at building a 100 kg high pressure 136 Xe gas TPC, to be hosted in the Canfranc Underground Laboratory(LSC), in Spain. This paper address the novel design concept of NEXT TPC believed to provide a pathway for an optimized and robust double-� experiment.