Production of neutron-rich isotopes by cold fragmentation in the reaction "1"9"7Au + Be at 950 A MeV

The production cross sections and longitudinal-momentum distributions of very neutron-rich isotopes have been investigated in the fragmentation of a 950 A MeV "1"7"9Au beam in a beryllium target. Seven new isotopes ("1"9"3Re, "1"9"4Re, "1"9"1W, "1"9"2W, "1"8"9Ta, "1"8"7Hf and "1"8"8Hf) and the five-proton-removal channel were observed for the first time. The reaction mechanism leading to the formation of these very neutron-rich isotopes is explained in terms of the cold-fragmentation process. An analytical model describing this reaction mechanism is presented. (orig.)Available from TIB Hannover: RO 801(99-35) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

#beta#-decay of "4"0Ti

The #beta#-decay of "4"0Ti was studied. The Fermi and Gamow-Teller strength function was deduced from the observed #beta#-delayed emission of protons and #gamma#-rays and from the measured half-life of 55(2) ms. The results are compared to shell-model predictions and are used to estimate the neutrino-capture rate of the solar-neutrino detector ICARUS. (orig.)Available from FIZ Karlsruhe / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Total charge-changing cross sections for neutron-rich light nuclei

Total charge-charging cross sections at relativistic energies on a carbon target have been measured for the light stable and neutron-rich radioactive nuclei "1"4Be, "1"0"-"1"9B, "1"2"-"2"0C, "1"4"-"2"3N, "1"6"-"2"4O, and "1"8"-"2"7F. A combined analysis of interaction and total charge-changing cross sections allows to draw definite conclusions concerning the thickness of the neutron skins or the size of the neutron halos for very neutron-rich isotopes. The obtained cross sections are also important in astrophysical applications to describe the propagation of galactic cosmic rays through the interstellar medium. A simple parameterization can reproduce the total charge-changing cross section within an accuracy of 5% for light nuclei from the valley of #beta#-stability up to the drip line. These systematics improve the predictive capability of the formulae used to describe the unknown cross sections. (orig.)Available from TIB Hannover: RO 801(2000-07) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Beta-decay of "4"0Ti and "4"1Ti and implication for solar-neutrino detection

The #beta#-decay of "4"0Ti and "4"1Ti was studied by measuring the #beta#-delayed proton- and #gamma#-emission. The half-lives for "4"0Ti and "4"1Ti were determined to be 54(2) and 82(3) ms, respectively. The experimental #beta#-decay strengths are compared with shell-model calculations and results from other measurements. The integrated Gamow-Teller strengths for "4"0Ti and "4"1Ti were found to be quenched, compared to the calculations, by factors of 0.79(3) and 0.93(3), respectively. Based on the experimental "4"0Ti #beta#-decay strength, the neutrino absorption cross-section and induced neutrino event rates for "4"0Ar were determined to be 14.3(3) x 10"-"4"3 cm"2 and 9.4#+-#0.2(stat.)_-_1_._6"+"1"."3(syst.) SNU, respectively. (orig.)Available from TIB Hannover: RO 801(98-19) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman