High-spin states and lifetime measurements in [formula omitted]Hf

• Published in: Nuclear physics. A 2000, Vol.673 (1), p.3-30
• Main Authors: Cullen, D.M., Reed, A.T., Appelbe, D.E., Wilson, A.N., Paul, E.S., Bergström, M.H., Sharpey-Schafer, J.F., Baktash, C., Frosch, I., Lee, I.Y., Macchiavelli, A.O., MacLeod, R.W., Prevost, D., Theisen, Ch, Curien, D.
• Format: Article
• Language: English
• Subjects: [formula omitted]Hf deduced high-spin levels, [formula omitted] band structure; [formula omitted]Hf Doppler Shift Attenuation measurement of mean lifetimes of collective states, transition quadrupole moments; Comparison with Total Routhian Surface calculations; Comparison with Woods–Saxon cranking calculations, [formula omitted](M1) [formula omitted](E2) ratios; Enriched targets, eurogam ii spectrometer; Enriched targets, gammasphere spectrometer; Measured [formula omitted]; Nuclear Experiment; nuclear structure[formula omitted]Gd( [formula omitted]O,7n), [formula omitted] MeV; nuclear structure[formula omitted]Te( [formula omitted]Ca,5n), [formula omitted] MeV; Physics
• ISSN: 0375-9474; 1873-1554
• DOI: 10.1016/S0375-9474(00)00061-0

This paper describes the results of two complementary experiments which studied the properties of the well-deformed nucleus 171 Hf. The first experiment, with a thin self-supporting target, extended the rotational bands built upon the [633]7 /2, [512]5 /2 and [521]1 /2 configurations up to spins of 73 /2–85 /2ℏ. The configurations of these bands and observed band crossings are discussed within the framework of the cranked-shell model. The second experiment employed a backed target in order to measure the lifetimes, by the Doppler Shift Attenuation method, and thereby establish deformations for some of the states in the collective rotational bands. The extracted deformations are found to be consistent with those predicted from theoretical Total Routhian Surface calculations. These deformations provide strong evidence that the high-spin states in 171 Hf, and perhaps more importantly, in the region where the high- K ( K π=19/2 + and K π=23/2 − ) isomeric states decay, retain their well-deformed axial symmetry.