On the <i>Q</i> -value of the tritium β-decay

Abstract

We report here the atomic masses of 3 H and 3 He determined by using the Penning trap mass spectrometer Smiletrap.The measurements are based on cyclotron frequency determinations of 3 H 1+ and 3 He 1+ using H + 2 ions as mass reference.The mass values for 3 H and 3 He 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 -decay was derived resulting in 18.589 8(12) keV, being the most accurate value at present.The Q-value of the tritium -decay is related to the possible rest mass of the electron antineutrino.