Ramsey's method of separated oscillatory fields is applied to the excitation of the cyclotron motion of short-lived ions in a Penning trap to improve the precision of their measured mass. The theoretical description of the extracted ion-cyclotron-resonance line shape is derived out and its correctness demonstrated experimentally by measuring the mass of the short-lived 38Ca nuclide with an uncertainty of 1.6⋅10−8 using the ISOLTRAP Penning trap mass spectrometer at CERN. The mass value of the superallowed beta-emitter 38Ca is an important contribution for testing the conserved-vector-current hypothesis of the electroweak interaction. It is shown that the Ramsey method applied to mass measurements yields a statistical uncertainty similar to that obtained by the conventional technique ten times faster.
@article{arxiv.nucl-ex/0701027,
title = {Separated Oscillatory Fields for High-Precision Penning Trap Mass Spectrometry},
author = {S. George and S. Baruah and B. Blank and K. Blaum and M. Breitenfeldt and U. Hager and F. Herfurth and A. Herlert and A. Kellerbauer and H. J. Kluge and M. Kretzschmar and D. Lunney and R. Savreux and S. Schwarz and L. Schweikhard and C. Yazidjian},
journal= {arXiv preprint arXiv:nucl-ex/0701027},
year = {2008}
}