Track experiment for study on the 136Xe double β-decay

A facility for track experiment on studying 136Xe 2β-decay, based on 13m3 proportional drift detector and designed for 10 kg Xe, being under construction in ITEP, is considered. Detector prototype of 0.3m3 in volume with 0.5 kg 136Xe is described. Use of tracking data permits to have high (∼105) background suppression factor working on the Earth surface. The facility efficiency is 2%, providing the chosen energy range is 0.2-1.0 MeV and emergence angle in relation to magnetic field is 30-80 deg. The measured results show that the lower limit for 136Xe half-decay time with neutrino emission 136Xe→136Ba+2e-bar+2ν constitutes T1/2(2β2ν)≥6.0x1018 years (the confidence level 68%)