Identification of Triaxial Strongly Deformed Bands and Spectroscopy of High-Spin Normal Deformed Structures in 164Hf
Marsh, Jarrod Christopher
CommitteeArnoldus, Hendrik F.
Dunne, James A.
Winger, Jeffry A.
This research encompasses threemajor segments: a search for high-spin triaxial strongly deformed (TSD) bands in 164Hf, spectroscopy of high-spin normal deformed (ND) bands in 164Hf, and a low-spin search in 165Ta. In April 2010, an experiment was carried out using the ATLAS linear accelerator at Argonne National Laboratory (Argonne, IL). A thin (761 microgram/square centimeter) 94Zr target was impacted with a 330MeV 74Ge beam. This produced a 168Hf compound nucleus that decayed via the 4n channel to 164Hf. Offline data analysis was performed using coincidence relationships and gamma-ray intensity analysis to determine the decay pathways and Directional Correlation of Oriented Nuclei (DCO ratios) to determine level spin and parities. The highest extend of the 164Hf level scheme in previous works was near 32 hbar. This research has extended the previously known level scheme to 48 hbar. Seven new normal deformed bands and two triaxial strongly deformed bands have been added. Decay pathways of TSD bands to ND states have been firmly established. Intrinsic configurations of the bands were discussed based on Cranked Shell Model (CSM) calculations. A short discussion of new low-spin structures in 165Ta concludes the research. The experiment was carried out in August 2010 at Yale’s Wright Nuclear Structure Laboratory using their tandem linac. A 228MeV 51V beam was incident upon a 118Sn self-supporting thin target. Data was sorted into gamma-gamma matrices using the WNSL CSCAN code. Three new normal deformed low-spin structures were found, and one previously known but unpublished structure was confirmed, extended, and linked to the Yrast band.