K. Schmidt

Production of very neutron-deficient isotopes near 100Sn via reactions involving light-particle and cluster emission

Abstract The production of very neutron-deficient isotopes near 100Sn has been investigated by using on-line mass separation of evaporation residues produced by heavy-ion induced complete-fusion reactions. We measured the cross sections for 99Cd, 100In, 101Sn and 102In via 58Ni+58Ni fusion reactions followed by cluster emission, and via 58Ni+50Cr fusion reactions accompanied by evaporation of protons, neutrons or α particles. Both types of reactions yield similar cross sections for the production of exotic nuclei near 100Sn. The data are discussed in comparison with results obtained from statistical-model calculations.

Beta decay of 56 Cu

AbstractThe proton-rich isotope 56 Cu was produced at the GSI On-Line Mass Separator by means ofthe 28 Si( 32 S, p3n) fusion–evaporation reaction. Its β -decay properties were studied by detecting β -delayed γ rays and protons. A half-life of 93± 3 ms was determined for 56 Cu. Compared to theprevious work, six new γ rays and three new levels were assigned to the daughter nucleus 56 Ni. Themeasured Gamow–Teller strength values for five 56 Ni levels are compared toshell-model predictions.  2001 Elsevier Science B.V. All rights reserved. PACS: 21.10.-k; 23.40.-s; 21.60.Cs; 27.40.+zKeywords: R ADIOACTIVITY 56 Cu ( β + ) [from 28 Si( 32 S, p3n)]; Measured E γ , I ; Deduced β -intensity and β -strength distribution; 56 Ni deduced levels J,π ; On-line mass separation; Plastic scintillation detectors; Gedetectors. N UCLEAR STRUCTURE 56 Ni; Calculated levels; Gamow–Teller strength; S HELL MODEL * Corresponding author.E-mail address:e.roeckl@gsi.de (E. Roeckl). 1 Present address: Instituut voor Kern- und Stralingsfysica, University of Leuven, B-3001 Leuven, Belgium.

Decay of 114Ba

We measured for the first time the α decay of 114Ba. The α decay of the daughter and granddaughter nuclei 110Xe and 106Te was also observed and the hitherto unknown half‐life of 110Xe was determined. The resulting α‐decay Q‐values and reduced widths as well as the Q‐value for 12C cluster decay of 114Ba are discussed in comparison with theoretical predictions.

Evidence for the 2p decay of 45Fe from GSI

In an experiment performed at the GSI Fragment Separator the decay of 45Fe has been investigated. Five 45Fe atoms were implanted in a silicon telescope mounted inside a high‐efficiency NaI detector. The implantation events were correlated with radioactive decay signals. One of them was consistent with the β decay of 45Fe accompanied by the emission of a 10 MeV proton. In each of the four other decay events, a signal corresponding to the emission of 1.1 ± 0.1 MeV particle(s) was recorded with no coincident signals in the NaI detector. This observation represents the first evidence for the two‐proton ground state decay of 45Fe. The time distribution of the observed decay events corresponds to a half‐life of 3.2−1.0+2.6 ms.

The art of digital spectroscopy — a new tool in action

A new generation of pulse processing electronics was successfully tested on-line and applied for the first time in particle and gamma-ray spectroscopy experiments. It is based on a Digital Signal Processing (DSP) technology.