118334834
Two experiments in neutrino physics: Double beta decay of cadmium-116 and the efficiency of an argon-40 neutrino detector
121755167
Electron capture decay of In-116 and nuclear structure of double beta decays
Quasiparticle-random-phase-approximation (QRPA) calculations of double {beta} decays have not been able to reproduce data in the A=100 system. We propose the A=116 system{emdash}because of its smaller deformation{emdash}as a simpler system to test QRPA calculations. We present results of two experiments we performed, which determine the electron-capture-decay branch of {sup 116}In to be (2.27{plus_minus}0.63){times}10{sup {minus}2}{percent}, from which we deduce logft=4.39{sub {minus}0.15}{sup +0.10}. We present QRPA calculations and compare their predictions to experimental data. Finally we use these calculations to predict the 2{nu} double-{beta}-decay rate of {sup 116}Cd to the ground and excited states of {sup 116}Sn. {copyright} {ital 1998} {ital The American Physical Society}
45540139
Precise study of the final-state continua in 8 Li and 8 B decays
We studied β-delayed singles-α spectra from 8Li and 8B decays with special emphasis on a careful calibration of the energy scale. 8Li and 8B activities were produced by 7Li(d, p) and 6Li(3He,n) reactions, respectively, and deposited in thin C foils. Delayed α’s were counted in thin, cooled Si detectors with small solid angles to reduce summing with β’s. The energy scale and detector response were calibrated with spectroscopic grade radioactive sources. We extracted the 8Li and 8B final-state continuum shapes from our spectra by using R-matrix analyses that included effects of lepton-recoil broadening and detector response. Our results are in excellent agreement with a recent measurement using 8B’s implanted in a Si counter and in good agreement with our reanalysis of the older Wilkinson-Alburger 8Li and 8B data, but disagree with a recent 8B experiment using a coincidence technique.
119118939
Helium nuclei around the neutron drip line
Neutron rich He nuclei have been investigated using relativistic mean field approach in co-ordinate space. Elastic partial scattering cross sections for proton scattering in inverse kinematics have been calculated using the theoretically obtained density for $^{6,8}$He and compared with experiment. The energies of the low-lying resonance states in the neutron unstable nuclei $^{5,7}$He have also been calculated and compared with experimental observations.
118982481
Neutron drip line in odd and even mass calcium and nickel nuclei
Neutron-rich Ca and Ni nuclei have been studied in a spherical relativistic mean-field formalism in coordinate space. A {delta} interaction has been adopted to treat the pairing correlations for the neutrons. Odd nuclei have been treated in the blocking approximation. The effect of the positive-energy continuum and the role of pairing in the stability of nuclei have been investigated by use of the resonant-BCS approach. In Ca isotopes, N=50 is no longer a magic number, whereas in Ni nuclei, a new magic number emerges at N=70. There is a remarkable difference in the relative positions of the drip lines for odd and even isotopes. In Ca isotopes, the last bound even and odd nuclei are found to be {sup 72}Ca and {sup 59}Ca, respectively. In Ni isotopes, the corresponding nuclei are {sup 98}Ni and {sup 97}Ni, respectively. The origin of this difference in relative positions of the drip line in even and odd isotopes in the two chains is traced to the difference in the single-particle level structures and consequent modification in the magic numbers in the two elements. Pairing interaction is seen to play a major role. The effect of the width of the resonance states on pairing hasmore » also been investigated.« less
119481144
Role of pairing interaction in neutron rich odd and even Zr nuclei
Neutron rich Zr nuclei with number of neutrons between N=50 and 82 are investigated in the relativistic mean field approach in coordinate space. The resonant levels in the positive energy continuum have been explicitly included in the calculation. Odd nuclei have been treated in the blocking approximation. Our calculation indicates that the dripline for odd mass isotopes is far away from that for the even mass ones. Pairing interaction plays a significant role in stabilizing the even isotopes, thus extending the dripline for them.