#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

Study of the #beta#-decays of "3"7Ca and "3"6Ca

The #beta#-delayed proton and #gamma#-ray emission of "3"7Ca and "3"6Ca was studied at the projectile fragment separator at GSI Darmstadt. In the "3"7Ga study, the #beta#-delayed #gamma#-decay was observed for the first time, and the half-life was redetermined, under essentially background-free conditions, as 181.1#+-#1.0 ms. The surprisingly high #GAMMA#_#gamma#/#GAMMA#_p values found for proton-unbound states in "3"7K drastically reduce former discrepancies between the Gamow-Teller strength value B(GT) measured in the "3"7Ca #beta#-decay and those deduced from the "3"7Cl(p, n)"3"7Ar mirror reaction. Our data provide evidence, on a level of 1.6 standard deviations, for isospin-mixing of the lowest T=3/2 level in "3"7K. In the "3"6Ca study, a complete #beta#-decay scheme, including the #beta#-delayed proton emission into the ground and first excited states of "3"5Ar as well as the #beta#-delayed #gamma#-decay, was measured for the first time. The "3"6Ca half-life was remeasured with improved accuracy to be 102#+-#2 ms. Our data exclude a 1"+ assignment for two near-threshold states in "3"6K that could be important resonances in "3"5Ar(p, #gamma#) reactions of astrophysical interest. The B(GT) distributions in "3"7","3"6Ca decays are compared to results obtained from large-scale sd shell-model calculations. (orig.)Available from FIZ Karlsruhe / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Nuclear structure near the doubly-magic "1"0"0Sn

The single particle (hole) energies in "1"0"0Sn, as extrapolated by a shell model analysis of the neighbouring nuclei, show a remarkable similarity to those in "3"6Ni, one major shell lower. This is borne out in nearly identical I"#pi#=2"+ excitation energies, implying E(2"+)#approx =#3 MeV in "1"0"0Sn, and a large neutron effective E2 charge #epsilon##>=#1.6#epsilon#. In contrast a small proton polarisation charge #delta##epsilon##<=#0.3#epsilon# is found, pointing to a large isovector charge. Mean field predictions for single particle energies show substantial deviations from the experimental extrapolation. From the experimental two-proton hole spectrum in "9"8Cd an improved empirical interaction is extracted for the #pi#(p_1_/_2,g_9_/_2) model space yielding a good description of the N=50 isotones "9"5Rh to "9"8Cd. In "1"0"4Sn, for the first time in this region, strong E3 transitions with B(E3)#>=#17 W.u. were identified, indicating E(3"-)#approx =#3 MeV in "1"0"0Sn. New experimental devices, as the Ge-cluster cube and total absorption spectrometers, applied in a pioneering experiment to the #beta#"+/EC decay of "9"7Ag, have led to a consistent picture of the Gamow-Teller quenching around "1"0"0Sn. The experimental results are discussed in the framework of various shell model approaches by using both empirical and realistic interactions. (orig.)Available from TIB Hannover: RO 801(98-62) / 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

Direct observation of systematic deviations from the Bethe stopping theory for relativistic heavy ions

The SIS accelerator facilities at GSI in combination with the magnetic spectrometer FRS allow the direct measurement of stopping powers for relativistic heavy ions up to uranium with high precision for the first time. Here, we report on representative results obtained for projectiles up to xenon in the energy range from (700-1000) MeV/u. Systematic deviations from the Bethe stopping-power theory are observed, whereas the data are in good agreement with theory one Mott and Bloch corrections and the Fermi density effect are included. (orig.)Part of the Ph.D. thesis of C. ScheidenbergerAvailable from TIB Hannover: RO 801(94-11) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Beta-decay of "5"6Cu

By measuring positrons and #beta#-delayed #gamma#-rays emitted from mass-separated sources, the decay of "5"6Cu(4"+,T_z=-1,T=1) to states in the doubly-magic nucleus "5"6Ni was studied for the first time. The half-life of "5"6Cu was measured to be 78(15) ms, and four #beta#-delayed #gamma#-rays were assigned to its decay. The resulting experimental data on Fermi and Gamow-Teller strength are compared with shell-model predictions. (orig.)Available from TIB Hannover: RO 801(98-12) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Beta-delayed proton decay of a high-spin isomer of "9"4Ag

We have observed the high-spin states in "9"3Rh populated by delayed-proton emission following the #beta# decay of "9"4Ag. The existence of a second isomer in "9"4Ag with I#>=#17, T1/2=0.42(5) s, whose #beta#-decay energy is at least 15.5 MeV, has been established. This state features most likely the highest spin ever observed for #beta#-decaying nuclei. (orig.)SIGLEAvailable from TIB Hannover: RO 801(03-08) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Beta decay of the new isotope "1"0"1Sn

The very neutron-deficient isotope "1"0"1Sn has been produced in a "5"0Cr("5"8Ni, 2p5n) reaction and its decay has been studied for the first time. Energy and time spectra of beta-delayed protons emitted from samples that were prepared by using chemically selective ion sources of an on-line mass separator have been measured. The half-life of "1"0"1Sn was determined to be 3#+-#1 s. The results obtained are compared to theoretical predictions. (orig.)SIGLEAvailable from TIB Hannover: RO 801(94-47) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Gamow-Teller strength in the beta-decay of "3"7Ca and its implications for the detection of the solar neutrino flux

We have studied the #beta#-decay of "3"7Ca at the projectile fragment separator FRS and GSI Darmstadt. The resulting Gamow-Teller strength function B(GT) which is important for determining the detection efficiency of the Homestake mine "3"7Cl detector is significantly changed by the inclusion of previously unobserved #beta#-delayed #gamma#-rays. With the new results former discrepancies between the B(GT) values measured in the "3"7Ga #beta#-decay and those extracted from "3"7Cl(p, n)"3"7Ar reactions are drastically reduced. Additionally, our data yield evidence for an isospin-forbidden Fermi transition in the #beta#-decay of "3"7Ca. (orig.)SIGLEAvailable from TIB Hannover: RO 801(94-67) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Gamow-Teller strength in the #beta#-decay of "3"6Ca

The #beta#-decay of "3"6Ca has been studied at the projectile fragment separator at GSI Darmstadt. The Gamow-Teller strength function B(GT), deduced from the observed #beta#-delayed proton- and #gamma#-emission and from the measured half-life of 102(2) ms, is compared to results obtained from large-scale sd-shell model calculations. (orig.)SIGLEAvailable from TIB Hannover: RO 801(94-84) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman