The DCBA experiment for neutrinoless double beta decay

Abstract

Neutrinoless double beta decay experiment is the only realistic method to investigate the Majorana nature and the absolute mass scale of neutrinos. The DCBA (Drift Chamber Beta-ray Analyzer) experiment can separately detect electrons from other background particles in a uniform magnetic field. The kinetic energy of each electron is obtained from its momentum measurement. Therefore no energy calibration is required. The test prototype DCBA-T2 obtained the energy resolution of about 150 keV (FWHM) for 976 keV internal conversion electrons from 207Bi More improved prototype DCBA-T3 is now under construction. Its energy resolution is expected to be less than 100 keV (FWHM) according to the simulation study with Geant4. The future detector (temporarily called Magnetic Tracking Detector: MTD) enlarged from DCBA-T3 can investigate effective neutrino mass down to about 0.03 eV, if sufficient amount of 150Nd source is available.