-decay half-lives of very neutron-rich isotopes of elements
from Ti to Ni
F. Ameil1,2 - M. Bernas1 - P. Armbruster2 - S. Czajkowski3 - Ph. Dessagne4 - H. Geissel2 - E. Hanelt5 - C. Kozhuharov2 - C. Miehe4 - C. Donzaud1 - A. Grewe5 - A. Heinz5 - Z. Janas6 - M. de Jong5 - W. Schwab2 - S. Steinhäuser5
1 Institut de Physique Nucléaire d'Orsay, IN2P3-CNRS, F-91406 Orsay
cedex, France
2 Gesellschaft für Schwerionenforschung, Planckstraße 1 D-64220 Darmstadt,
Germany
3 Centre d'Etude Nucléaire de Bordeaux-Gradignan, IN2P3-CNRS, BP 120 F-33175
Gradignan Cedex, France
4 Institut de Recherches Subatomiques, IN2P3-CNRS BP28 F-67037 Strasbourg cedex
2, France
5 Institut für Kernphysik, Technische Hochschule Darmstadt, Schloß
gartenstraße 9, D-64289 Darmstadt, Germany
6 Instytut Fizyki Doswiadczalnej, Uniwersytet Warszawski, Hoza 69 PL-00681
Warszawa, Poland
Received: 1 October 1997 Communicated by V. Metag
Abstract
The unknown -decay half-lives of 22 isotopes far off
stability ( 5 < TZ < 10 ) in the region from Ti to Ni were measured at
GSI, Darmstadt. The nuclei were produced in a fragmentation reaction of 500
A.MeV 86Kr-projectile impinging on a thick Be target. The isotopes of
interest were separated and identified with the fragment separator, FRS, by a
combination of B
, Z, and ToF techniques. An additional range
separation was performed by a selective implantation into granular
detectors. The spatial and time correlations of the implant with the
consecutively detected -particles were used to determine the unknown
half-lives. For nuclei far off stability, -decay chains were measured
and analyzed as well, leading to an even more reliable evaluation of the
lifetimes. The large discrepancies found between the measured and the
theoretical values emphasize that most recent theoretical work is not an
improvement over calculations made almost a decade ago.
PACS
23.40.-s decay, double decay, electron and muon
capture -
27.30.+t 
-
27.50.+e 
Copyright Springer-Verlag
