0000000000535290
AUTHOR
T. Mehren
Neutron-rich isotopesTi54−57
The neutron-rich isotopes $^{54\mathrm{\ensuremath{-}}57}\mathrm{Ti}$ and $^{58\mathrm{\ensuremath{-}}60}\mathrm{Cr}$ are produced by fragmentation of a 64.5 MeV/nucleon $^{65}\mathrm{Cu}^{26+}$ beam in a 90 mg/${\mathrm{cm}}^{2}$ $^{9}\mathrm{Be}$ target. Following particle identification by energy loss and time of flight, the radioactive decay was observed by \ensuremath{\beta} singles and \ensuremath{\beta}\ensuremath{\gamma}-coincidence measurements. The results obtained for $^{58\mathrm{\ensuremath{-}}60}\mathrm{Cr}$ are compared to previous results, whereas the decay of the $^{54\mathrm{\ensuremath{-}}57}\mathrm{Ti}$ isotopes is studied here. \ensuremath{\gamma}-ray intensities and en…
Beta-Decay Half-Lives and Neutron-Emission Probabilities of Very Neutron-Rich Y to Tc Isotopes
Neutron-rich {sub 39}Y to {sub 43}Tc isotopes have been produced by fission of uranium with a 50MeV H{sub 2}{sup +} beam. Beta-decay half-lives, delayed neutron-emission probabilities, and production yields have been measured and compared with theory. Beta decay of 4 new isotopes is reported, and the {beta}-delayed neutron-emission mode has been discovered for 12 isotopes of the elements niobium and technetium. The results compared to quasiparticle random phase approximation predictions indicate the increasing importance of fast {beta} transitions to high-lying states of nuclei with large neutron excess. {copyright} {ital 1996 The American Physical Society.}
First beta-decay studies of the neutron-rich isotopes 53-55Sc and 56-59V
The neutron-rich isotopes Sc53-55 and V56-59 have been produced at GANIL in interactions of a 64.5 MeV/u Cu-65 beam with a Be-9 target. They were separated by the doubly achromatic spectrometer LISE3. Beta-decay half-lives and subsequent low-energy gamma-rays were observed for the first time. The present results are compared to QRPA model predictions. The quick drop of the half-life observed at N = 33 for Ca-53(20)33 is water V-56(23)33 and absent for Sc-54(21)33, indicating a vanishing of the N = 32 subshell north to Ca-52(32). In an astrophysical context, these neutron-rich isotopes represent r-process progenitors which, after beta-decay, would produce the correlated isotopic over-abundan…
Beta-decay studies of far from stability nuclei near N = 28
Abstract Beta-decay half-lives and β-delayed neutron-emission probabilities of the very neutron-rich nuclei 43 P, 42,44,45 S and 44–46 Cl, 47 Ar, which lie at or close to the N=28 magic shell, have been recently measured through β or β-n time correlation measurement. The results are compared to recent model predictions and indicate a rapid weakening of the N=28 shell effect below 48 Ca. The nuclear structure effects reflected in the decay properties of the exotic S and Cl isotopes may be the clue for the astrophysical understanding of the unusual 48 Ca 46 Ca abundance ratio measured in the solar system.