Energy and efficiency calibration of an array of six Euroball Cluster detectors used for beta-decay studies

The use of an array of 6 euroball cluster detectors, i.e. 42 large-volume germanium detectors, for beta-decay studies is described. The solid angle with respect to a source placed in the center of the array amounts to 65% of 4#pi# sr. The total photo-peak efficiency for 1.33 MeV #gamma#-rays is 10.2(5)%, without ''adding back'' the Compton-scattered events. For this #gamma#-ray energy, the energy resolution of the entire setup is 2.8 keV. The performance of the array up to #gamma#-ray energies of 8 MeV is discussed, and alternative ways of determining the photo-peak efficiency are presented. (orig.)13 refs.Available from TIB Hannover: RO 801(98-37) / 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

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

Decay studies of the neutron-deficient isotopes "1"1"4"-"1"1"8Ba

Radioactivity "1"1"4","1"1"5","1"1"6Ba [from "5"8","6"0Ni("5"8Ni, xn), E=3.5-4.3 MeV/u]; "1"1"6","1"1"7","1"1"8Ba [from "6"3Cu("5"8Ni, pxn), E=4.3-4.9 MeV/u]; Measured E_p, I_p, E_#gamma#, I_#gamma#, #gamma##gamma#-coin, T_1_/_2; deduced cross-sections. Ge, Si, scintillator detectors, on-line mass separation. (orig.)Available from TIB Hannover: RA 801(97-36) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Non-observation of "1"2C cluster decay of "1"1"4Ba

By means of the on-line mass separator at Gesellschaft fuer Schwerionenforschung, Darmstadt, we produced "1"1"4Ba through the "5"8Ni("5"8Ni,2n) reaction, separated it as a "1"1"4Ba"1"9F"+ beam, and implanted it into a stopper foil positioned in the center of an array of track detectors, which were used to search for "1"2C radioactivity of "1"1"4Ba. A total number of (5.4#+-#1.7).10"4 "1"1"4Ba atoms were implanted. No "1"2C event was found after a total exposure time of 116 hours, corresponding to a "5"8Ni beam dose of 1.3.10"1"7. The resulting upper limit of 3.4.10"-"5 (84% c. 1.) for the branching ratio for "1"2C decay of "1"1"4Ba is considerably lower than the limits obtained in previous experiments, which represents an inconsistency at levels of more than 90%. A semiempirical estimate of 19.3 MeV for the upper limit of the Q-value for "1"2C decay of "1"1"4Ba is derived. (orig.)SIGLEAvailable from TIB Hannover: RO 801(97-58) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Large spin alignment of the unbound "5He fragment after fragmentation of 240 MeV/u"6He

Peripheral fragmentation of a 240 MeV/u beam of the halo nucleus "6He incident on carbon target has been studied in a kinematically complete experiment. It is found that one-neutron stripping to the unbound nucleus "5He is the dominant fragmentation mechanism and that it leads to a spin alignment of "5He in a plane perpendicular to the "5He momentum vector. This is expected to be a common feature for all neutron halo nuclei. (orig.)Available from FIZ Karlsruhe / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman