Study of the superdeformed band in 194Pb and 192Hg with EUROGAM
Abstract
A subset of the Eurogam array has been used to investigate the decay out of the superdeformed (SD) band in 194Pb. Two new band members and a new decay pattern into the low lying states at normal deformation (ND) have been established for this band. In the level scheme at normal deformation, the linking transitions between the previously known floating ΔI = 1 sequence and the lower states have been established for the first time. In this talk we will also report on the preliminary results of the search for the linking transitions between the SD and ND states in 192Hg with the fully operational EUROGAM array.
References (12)
- R.R. Chasman
Phys. Lett.
(1990) - P. Van Duppen
Phys. Rev.
(1987) - A.G. Smith
- K. Théine
Z. Phys.
(1990)H. HübelNucl. Phys.
(1990) - M.J. Brinkman
Z. Phys.
(1990) - P. Willsau
Cited by (14)
Nuclear Data Sheets for A=194
2021, Nuclear Data SheetsExperimental nuclear structure and decay data are evaluated for all of 14 known nuclides of mass 194 (Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po, At, Rn). Detailed evaluated spectroscopic information is presented for each reaction and decay experiment, and by combining all the available data, recommended values are provided for energies, spins and parities and half-lives of levels, together with energies, branching ratios and multipolarities of gamma radiations from the levels, and characteristics of beta and alpha radiations in radioactive decays. No excited states have yet been identified in 194Ta, 194W, and 194Rn. Only limited spectroscopic data are available for 194Re, with a 45−μs isomer identified, but its absolute energy yet to be determined. Only two levels at unknown absolute energies are reported for 194At, both of which are isomeric but neither can be unambiguously identified as the ground state. Data are scarce for 194Os, 194Bi and 194Po, while 194Pt, 194Au, 194Hg, 194Tl and 194Pb are well studied through decays and reactions. For 194Ir, although a major (n, γ), E=thermal study and two particle-transfer studies provide large amounts of spectral data, still several problematic issues are found in the assignment of multipolarities for the secondary gamma transitions in the (n, γ) study by 2008Ba25, 1998Ba85 and 1998Ba42, all from the same group. Some issues have been resolved by the evaluators, but we suggest that further experimental work is needed on 194Ir structure to resolve standing issues, and verify the conclusions made by 2008Ba25. Our attempt to contact the prime authors of the 2008Ba25 paper was not successful. The present work supersedes all the earlier evaluations of A=194 nuclides by 2006Si17, 1996Br26, 1989Si01 and 1972Au11.
Nuclear Data Sheets for A = 192
2012, Nuclear Data SheetsExperimental structure and decay data for all nuclei with mass A=192 (Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po, At) have been evaluated. This evaluation, covering data received by 15 June 2012, supersedes the 1998 evaluation by C. M. Baglin (Nuclear Data Sheets 84, 717 (1998), literature cutoff August 1998) and the subsequent inclusion in the ENSDF database of the new nuclide 192At (C. M. Baglin, literature cutoff 16 May 2006). It also incorporates the current evaluation of superdeformed-band information by B. Singh. Since the last publication, 192Ta, 192W and 192At have been observed, and an isomeric state has been identified in 192Re. The ε decay of 192Au has been studied using a multidetector array resulting in an extensively revised level scheme for 192Pt.
Nuclear Data Sheets for A = 194
2006, Nuclear Data SheetsNuclear spectroscopic information for known nuclides of mass number 194 (Re,Os,Ir,Pt,Au,Hg,Tl,Pb,Bi, Po,At) with Z = 75 to 85 and N = 119 to 109 have been evaluated and presented together with adopted energies and Jπ of levels in these nuclei. No excited state data are yet available for 194Re and 194At. Many superdeformed structures are known in A = 194: three SD bands in 194Hg, two of which are connected to the normal-deformed structures; six SD bands in 194Tl; and three SD bands in 194Pb, one of which is connected to the normal-deformed structure. In addition four magnetic-rotational (MR) dipole bands are known in 194Pb together with many other dipole bands which are probable multi-quasiparticle structures. This evaluation supersedes previous full evaluations of A = 194 published by 1996Br26, 1989Si01, 1977Ha46 and 1972Au11.
Nuclear data sheets for a = 192
1998, Nuclear Data SheetsExperimental data for all nuclei with mass A=192 have been evaluated. This evaluation, covering data received by August 1, 1998, supersedes the 1991 evaluation by V. S. Shirley (Nuclear Data Sheets64,205 (1991)). It also incorporates the evaluation of192Ir (73.827 d) decay prepared by Edgardo Browne as part of an ongoing international collaboration engaged in the evaluation of T1/2and radiation energy and intensity data for selected radionuclides (see comment with192Ir (73.827 d) ϵ decay and β−decay data sets).
Nuclear data sheets for A = 194
1996, Nuclear Data SheetsAbstract:Experimental data pertaining to all nuclei with mass A = 194 were evaluated. Level schemes from both radioactive decay and reaction studies are presented, along with associated tables of experimental data and adopted properties for levels and γ rays. The literature cutoff date for this revision is September 30, 1996. This revision replaces 89SiO1. Extensive high-spin experiments using large gamma-detector arrays have revealed superdeformed structures in194Hg (three SD bands: Yrast and pair of excited signature partners),194Tl (six SD bands: Three pairs of signature partners), and194Pb (three SD bands: Yrast and pair of excited signature partners). For yrast bands (SD-1) in194Hg and194Pb, connecting transitions between the SD band and normal bands have recently (96Kh04, 96Lo12,96Br07) been reported. Several dipole (oblate) bands in194Pb, some based on high-K (oblate) states have been reported from similar in-beam γ-ray experiments. New γγ coincidence measurements (93Ko59, 94KoZQ) using the193Ir(n,γ) reaction helped to place several transitions in the level scheme and established the 31.85-ms194Ir isomer at 147.078 KeV 5. Results from the first study of the193Ir(d,p) reaction (94Ga30) agree with those from (n,γ). Unpublished (95TeZZ) γγ coincidence results (using HERA, an array of 20 intrinsic germanium detectors) revealed a new level in194Pt at 1737.4 KeV. It also provided correct placement in the decay scheme for many γ rays from194Au ϵ decay. Recent measurements (92Hu04) of the α-decay chain202Fr–196At–194Bi confirm the existence of194Bi isomers, and show population to previously unknown levels at 218 and 396 KeV in194Bi.Cutoff Date:All data received by September 30, 1996 were evaluated.General Policies and Organization of Material:See the January issue of Nuclear Data Sheets.Acknowledgments:Evaluators wish to thank R.R.P. Teixeira (95TeZZ) for making available their unpublished data on194Au ϵ decay.General Comments:The analysis of γ-ray data is described in detail in 86BrZQ. The γ-ray energies given by various authors were fit to a level scheme for each data set through a weighted least-squares analysis. The scales for the corresponding intensities, which were assumed to be linearly related, were adjusted using the methods of Tepel (80TeZW) and Lederer (92LeZJ). Uncertainties of absolute γ-ray intensities were determined using the method of Browne (86Br21).
Quadrupole and octupole correlations in normal, superdeformed and hyperdeformed states of <sup>194</sup>Pb
1995, Nuclear Physics, Section AQuadrupole and octupole correlations in 194Pb are investigated by means of the generator coordinate method. Static microscopic wave functions are obtained by constrained Hartree-Fock+BCS calculations using the effective interaction SkM∗. Quadrupole deformations from ground state to hyperdeformation region are included. Superdeformed band heads of both parities are predicted. The depopulation of the even superdeformed band is calculated. The odd-parity superdeformed band slowly decays to the ground even-parity superdeformed band over many E1 transitions.