Decay properties of very neutron-deficient isotopes of silver and cadmium

The #beta#-decay properties of the lightest known silver and cadmium isotopes are investigated. Data for #beta#-delayed #gamma#-ray emission of "9"5"-"9"7Ag and for #beta#-delayed proton emission of "9"6Ag and "9"7Cd are presented. The experimental findings are compared with predictions of shell-model calculations in which a variety of model spaces and effective interactions are considered. (orig.)SIGLEAvailable from FIZ Karlsruhe / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

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 decay of neutron-deficient even-mass indium isotopes: evidence for population of highly-excited states in the cadmium daughter nuclei

By using mass-separated sources, positrons as well as #beta#-delayed protons and #gamma# rays were measured from the #beta# decay of "1"0"2In(T_1_/_2=22#+-#1 s) and "1"0"0In(T_1_/_2=6.1#+-#0.9 s). In particular, the average #beta#"+/(#beta#"++EC) ratio for the decay of "1"0"2In was measured to be 0.76(4) and a detailed level scheme of "1"0"2Cd was constructed. Whereas no direct #beta#"+/EC feeding of the identified "1"0"2Cd levels was observed, there is evidence for population of "1"0"2Cd states at high excitation energy followed by statistical #gamma# decay. This feature, which has been deduced on the basis of the measured positron spectrum and the measured #beta#"+/(#beta#"++EC) ratio of the "1"0"2In decay, is compared to the decay properties of the heavier odd-odd indium isotopes "1"0"4In, "1"0"6In and "1"0"8In, and is also used to interpret the observed #beta#-delayed proton data of "1"0"2In and "1"0"0In. For the first time, large-space shell-model calculations have been performed for the Gamow-Teller decay of heavy odd-odd nuclei. The decay results from these calculations are in good overall agreement with the gross decay properties of "1"0"2In and "1"0"0In deduced from the experiment. (orig.)SIGLEAvailable from TIB Hannover: RO 801(94-38) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Gamow-Teller strength distribution in the beta-decay of "1"0"0Ag from total-absorption gamma spectrometry

The EC/#beta#"+-decay of the odd-odd nucleus "1"0"0Ag was studied by means of total absorption #gamma#-ray spectrometry. Most of the Gamow-Teller strength was found to be concentrated at an excitation energy of 5.6 MeV in "1"0"0Pd, the FWHM of this resonance being 1.5 MeV. The measured strength distribution which is interpreted within the BCS approximation as being due to the dominant population of four-quasiparticle excitations, resembles the distribution predicted by an advanced shell-model calculation for the "9"8Ag#->#"9"8Cd decay. (orig.)Available from TIB Hannover: RO 801(94-66) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

The Gamow-Teller decay of "1"0"5Sn to three-particle states in "1"0"5In

The EC/#beta#"+ decay of "1"0"5Sn was reinvestigated by using "5"8Ni (5 MeV/u) + "5"0Cr reactions, chemically selective on-line mass separation and #gamma#-ray spectroscopy. The half-life of "1"0"5Sn has been determined as 34 #+-# 1 s. Out of 104 #gamma# transitions ascribed to the "1"0"5Sn decay, 89 have been placed in the decay scheme including 52 excited states of "1"0"5In. From the EC/#beta#"+ feeding of individual states, the distribution of the Gamow-Teller (GT) strength has been derived. It is shown that the main part of the GT strength is associated with the feeding of "1"0"5In levels having excitation energies above 3 MeV. This observation can be interpreted as a sign of dominant feeding of three-quasiparticle states in "1"0"5In, which correspond to the #pi#(g_9_/_2)"-"1 #nu#d_5_/_2 shell-model configuration spread over many levels. The sum of the GT strength deduced from the present gamma ray data of B_#SIGMA#(GT)=1.46 povides a lower limit to the total GT strength. Many weak transitions, mainly from high energy levels, may not have been detected in this study and therefore part of the strength may be missed. An indirect support for this conclusion has been obtained from the analysis of the indium KX-rays intensity. This analysis indicates about 50% contribution of the electron-capture to the beta decay of "1"0"5Sn, which is interpreted as a sign of a predominant feeding of the high-energy "1"0"5In states with B_#SIGMA#(GT)#>=#3. The observed GT distribution and strength will be compared to results obtained from a finite-Fermi-system theory and a large-basis shell-model calculation. The core-polarization and higher-order hindrance factors will be discussed. (orig.)SIGLEAvailable from TIB Hannover: RO 801(94-23) / 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

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