Europhys. Lett.
Volume 74, Number 3, May 2006
Page(s) 404 - 410
Section General
Published online 07 April 2006
Europhys. Lett., 74 (3), pp. 404-410 (2006)
DOI: 10.1209/epl/i2005-10559-2

On the $\mth{Q}$-value of the tritium $\mth{\beta}$-decay

Sz. Nagy1, T. Fritioff1, M. Björkhage2, I. Bergström2 and R. Schuch1

1  Atomic Physics, AlbaNova, Stockholm University - S-106 91 Stockholm, Sweden
2  Manne Siegbahn Laboratory (MSL) - Frescativägen 24, S-104 05 Stockholm, Sweden

received 17 November 2005; accepted in final form 7 March 2006
published online 7 April 2006

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)$\un{u}$ and 3.016 029 321 7(26)$\un{u}$, respectively. From these masses a new Q-value of the tritium $\beta$-decay was derived resulting in 18.589 8(12)$\un{keV}$, being the most accurate value at present. The Q-value of the tritium $\beta$-decay is related to the possible rest mass of the electron antineutrino.

07.75.+h - Mass spectrometers.
27.10.+h - Properties of specific nuclei listed by mass ranges: $A \le 5$.
32.10.Bi - Atomic masses, mass spectra, abundances, and isotopes.

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