Eur. Phys. J. A 15, 17-20 (2002)
DOI: 10.1140/epja/i2001-10216-x

Accurate mass measurements of very short-lived nuclei

Prerequisites for high-accuracy investigations of superallowed -decays

F. Herfurth¹, A. Kellerbauer¹, F. Ames², G. Audi³, D. Beck⁴, K. Blaum⁴, G. Bollen⁵, O. Engels², H.-J. Kluge⁴, D. Lunney³, R.B. Moore⁶, M. Oinonen⁷, E. Sauvan¹, C. Scheidenberger⁴, S. Schwarz⁵, G. Sikler⁴, C. Weber⁴ and the ISOLDE Collaboration<sup>1

1</sup>  CERN, 1211 Geneva 23, Switzerland
²  Sektion Physik, Ludwig-Maximilians-Universität München, 85748 Garching, Germany
³  CSNSM-IN2P3-CNRS, 91405 Orsay Campus, France
⁴  GSI, Planckstraße 1, 64291 Darmstadt, Germany
⁵  NSCL, Michigan State University, East Lansing MI 48824-1321, USA
⁶  Department of Physics, McGill University, Montréal (Québec) H3A 2T8, Canada
⁷  Helsinki Institute of Physics, University of Helsinki, P.O. Box 9, 00014 Helsinki, Finland

frank.herfurth@cern.ch

(Received: 21 March 2002 / Published online: 31 October 2002)

Abstract
Mass measurements of ³⁴Ar, Kr, and ^74,76Rb were performed with the Penning-trap mass spectrometer ISOLTRAP. Very accurate Q_EC-values are needed for the investigations of the -value of nuclear -decays used to test the standard model predictions for weak interactions. The necessary accuracy on the Q_EC-value requires the mass of mother and daughter nuclei to be measured with . For most of the measured nuclides presented here this has been reached. The ³⁴Ar mass has been measured with a relative accuracy of . The Q_EC-value of the ³⁴Ar decay can now be determined with an uncertainty of about 0.01%. Furthermore, ⁷⁴Rb is the shortest-lived nuclide ever investigated in a Penning trap.

PACS
21.10.Dr - Binding energies and masses.
24.80.+y - Nuclear tests of fundamental interactions and symmetries.

© Società Italiana di Fisica, Springer-Verlag 2002