C. J. Guess

Production and beta decay of rp-process nuclei 96Cd, 98In, and 100Sn.

The beta-decay properties of the N=Z nuclei 96Cd, 98In, and 100Sn have been studied. These nuclei were produced at the National Superconducting Cyclotron Laboratory by fragmenting a 120 MeV/nucleon 112Sn primary beam on a Be target. The resulting radioactive beam was filtered in the A1900 and the newly commissioned Radio Frequency Fragment Separator to achieve a purity level suitable for decay studies. The observed production cross sections of these nuclei are lower than predicted by factors of 10-30. The half-life of 96Cd, which was the last experimentally unknown waiting point half-life of the astrophysical rp process, is 1.03_{-0.21};{+0.24} s. The implications of the experimental T_{1/2} value of 96Cd on the abundances predicted by rp process calculations and the origin of A=96 isobars such as 96Ru are explored.

Production andβDecay ofrp-Process NucleiCd96,In98, andSn100

The beta-decay properties of the N=Z nuclei 96Cd, 98In, and 100Sn have been studied. These nuclei were produced at the National Superconducting Cyclotron Laboratory by fragmenting a 120 MeV/nucleon 112Sn primary beam on a Be target. The resulting radioactive beam was filtered in the A1900 and the newly commissioned Radio Frequency Fragment Separator to achieve a purity level suitable for decay studies. The observed production cross sections of these nuclei are lower than predicted by factors of 10-30. The half-life of 96Cd, which was the last experimentally unknown waiting point half-life of the astrophysical rp process, is 1.03_{-0.21};{+0.24} s. The implications of the experimental T_{1/2} value of 96Cd on the abundances predicted by rp process calculations and the origin of A=96 isobars such as 96Ru are explored.

Extraction of weak transition strengths via the (He-3, t) reaction at 420 MeV

Differential cross sections for transitions of known weak strength were measured with the (3He, t) reaction at 420 MeV on targets of 12C, 13C, 18O, 26Mg, 58Ni, 60Ni, 90Zr, 118Sn, 120Sn, and 208Pb. Using these data, it is shown that the proportionalities between strengths and cross sections for this probe follow simple trends as a function of mass number. These trends can be used to confidently determine Gamow-Teller strength distributions in nuclei for which the proportionality cannot be calibrated via beta-decay strengths. Although theoretical calculations in the distorted-wave Born approximation overestimate the data, they allow one to understand the main experimental features and to predict deviations from the simple trends observed in some of the transitions.

The (150)Nd((3)He,t) and (150)Sm(t,(3)He) reactions with applications to beta beta decay of (150)Nd

The

The Nd-150(He-3,t) and Sm-150(t,He-3) reactions with applications to beta beta decay of Nd-150

^{150}

beta-decay half-life of the rp-process waiting-point nuclide 84Mo

Nd(

LENDA: A Low Energy Neutron Detector Array for Studies of

^3

(p,n)

He,

Reactions With Radioactive Beams

t

Spectroscopy of 24 Al and extraction of Gamow-Teller strengths with the 24 Mg( 3 He,t) reaction at 420 MeV.

) reaction at 140 MeV/u and