On the Q -value of the tritium β-decay

Abstract
We report here the atomic masses of 3H and 3He determined by using the Penning trap mass spectrometer Smiletrap. The measurements are based on cyclotron frequency determinations of 3H1+ and 3He1+ using H2+ ions as mass reference. The mass values for 3H and 3He are 3.016 049 278 7(25) u and 3.016 029 321 7(26) u, respectively. From these masses a new Q-value of the tritium β-decay was derived resulting in 18.589 8(12) keV, being the most accurate value at present. The Q-value of the tritium β-decay is related to the possible rest mass of the electron antineutrino.