Look Up Calculated Gamow-Teller
Beta-Decay Half-Lives and
Beta-Delayed Occupation Probabilities


 We tabulate the beta-decay half-lives Tβ+ and Tβ- with respect to Gamow-Teller transitions. The β+ number is the half-life with respect to both beta-plus and electron-capture decay. We also tabulate the probabilites PA-k for producing a final nucleus with mass number A-k following beta decay and delayed emission of k neutrons. These probabilities are closely related to beta-delayed neutron-emission probabilities.

The beta-decay Q values and neutron separation energies used in these calculations were obtained from experimental mass differences when such masses were available, otherwise from calculated masses.

The beta-delayed occupation probabilities are only calculated inside the calculated neutron drip line in the daughter of the beta-minus decay.

Please note that:

1. The half-lives are calculated with respect to Gamow-Teller transitions. Fermi transitions and forbidden transitions are not considered.

2. The calculated half-lives close to stability are fairly uncertain because (a) we do not consider forbidden transitions and (b) close to stability small decay Q values enhance the effect of small uncertainties in the calculated position of the levels involved in the decay. An error of 500 keV in the postion of a level may change the calculated value by many orders of magnitude, or even from say a few minutes to infinity! Far from stability the same absolute error has a much lower effect on the calculated half-life, for example less than a factor of two at beta-decay Q values around 10 MeV.

Write proton number Z:

Write mass number A:

Downloading of calculated data files


 Three different data files are available for downloading:
  • The data file of calculated half-lives Tβ+ with respect to β+ decay and electron capture (EC) may be downloaded by clicking here. The format of the file is, in FORTRAN notation (2I5,1PE12.5), and each record contains:

    Z, N, Tβ+ (s)

    See above and the references at the end for a discussion of the accuracy of the calculated decay half-lives. If the nucleus is calculated to be stable with respect to Gamow-Teller decay the value 6.93147E+09 appears in the column of calculated values. Sometimes a higher number appears. Then the nucleus is calculated to have this half-life. However, such long, calculated half-lives are not reliable.

  • The data file of calculated half-lives Tβ- with respect to β- decay may be downloaded by clicking here. The format of the file is, in FORTRAN notation (2I5,1PE12.5), and each record contains:

    Z, N, Tβ- (s)

  • The data file with calculated probabilities PA-k for producing a final nucleus with mass number A-k following beta decay and delayed emission of k neutrons may be downloaded by clicking here. The format of the file is, in FORTRAN notation (2I5,3F10.4), and each record contains:

    Z, N, PA (%), PA-1 (%), PA-2 (%)

  • Forbidden decays have been taken into account in a phenomenological manner for β--decay only. The last reference below provides a link to this work and associated data file of half-lives and delayed-neutron-emission probabilities.

References:

Nuclear Properties for Astrophysical and Radioactive-Ion-Beam Applications,
by P. Möller, J. R. Nix, and K.-L. Kratz,
Atomic Data Nucl. Data Tables 66 (1997), 131-343.

A more detailed discussion of the model is in
New Developments in the Calculation of β-Strength Functions
P. Möller and J. Randrup Nuclear Physics A 514 (1990) 1-48

New calculations of gross beta-decay properties
for astrophysical applications ===>
``Speeding-up the classical r-process''
Peter Möller, Theoretical Division, Los Alamos National Laboratory, New Mexico 87545, USA
Bernd Pfeiffer and Karl-Ludwig Kratz, Institut für Kernchemie, Universität Mainz, Germany

ryxm@lanl.gov, moller@lanl.gov
Created April 8, 1996, Revisions 5 March 1997, 28 March 2012