Time-separated oscillatory fields for high-precision mass measurements on short-lived Al and Ca nuclides

High-precision Penning trap mass measurements on the stable nuclide 27Al as well as on the short-lived radionuclides 26Al and 38,39Ca have been performed by use of radiofrequency excitation with time-separated oscillatory fields, i.e. Ramsey's method, recently extended to Penning trap mass measurements of radioactive isotopes. A comparison with the conventional method of a single continuous excitation demonstrates the advantage of up to ten times shorter measurements. The new mass values of 26,27Al are compared to literature values and clarify conflicting data in this mass region. In addition, the resulting mass values of the superallowed β-emitter 38Ca as well as of the ground state of the β-emitter 26Alm confirm previous measurements