Jirina Stone

Abstract:

X-ray bursts have been suggested as a possible site for the astrophysical rp-process. The time scale for the process is governed by β-decay half-lives of several even-even N = Z waiting point nuclei, in particular, N = Z = 40 80Zr. A 4.1((+0.8)(-0.6))-s β+/EC half-life for 80Zr was determined by observing delayed 84-keV γ rays depopulating a T1/2 = 4-μs isomer at 312 keV in the daughter 80Y. As this half-life is lower than many previously predicted values, the calculated excessive production of A = 80 nuclides in astrophysical x-ray burst scenarios is reduced, and less extreme conditions are necessary for the production of heavier nuclides. © 2000 The American Physical Society.

Abstract:

The technique of beta -NMR/ON and its use for measurement of nuclear magnetic moments is briefly reviewed. Recent magnetic moment measurements are reported on Ni-67 and Cu-67. The relevance of magnetic moments of single-particle (hole) states for study of effects of configuration mixing and mesonic exchange currents is discussed.

Abstract:

Recent on-line nuclear orientation measurements of nuclear magnetic dipole moments by the method of NMR on oriented nuclei (NMR/ON) have yielded significant new odd-A moments. These include those closest to double magic 132Sn, namely, 133Sb [132Sn plus one g7/2+ proton] and 133Tem [132Sn with a pair of g7/2+ protons and one hole in the h11/2- neutron sub-shell]. These close-to-double-magic results allow stringent tests of nuclear moment theory including, as main contributions to deviations from the simple free nucleon (Schmidt limit) values, configuration mixing in the nuclear wavefunction and mesonic exchange current modification to the dipole moment operator. Comparison with theoretical prediction, using established approaches to both these corrections, is discussed showing success in medium mass nuclei comparable to results previously established in light [to 40Ca] and heavy [near 208Pb] nuclei.

Abstract:

Recent on-line nuclear orientation measurements of odd-A nuclear magnetic dipole moments of odd-A Sb, Te and I isotopes by the method of NMR on oriented nuclei mean that we now have complete series of odd-A moments up to, and including, those closest to the double shell closure at 132Sn. In this paper we consider the systematic changes in the measured moments as a function of proton number for the isotonic sequence 133Sb [g7/2+]1-139La [g7/2+]7 and as a function of neutron number for the isotopic sequences 125-133Sb and 127-135I and their interpretation using collective and shell model approaches.