Properties of intrinsic and rotational states in 175Ta

Physical Review C, 2005

High-spin states in 171 Ta were populated in the 124 Sn(51 V,4n) reaction at 228 MeV to search for evidence of stable triaxial deformation. Identification of a wobbling sequence based on the previously known πi 13/2 structure would provide a unique signature for this rarely observed shape. No such sequence was identified in these data, which suggests that the island of triaxial strongly deformed bands may be smaller than once thought. However, over 200 new transitions and two new bands were placed in the level scheme and the sequence based on the πi 13/2 orbital could be observed up to spin and parity I π = (101/2 +). The relative excitations of all the sequences were determined and the ground state of 171 Ta was found to have 5/2 + quantum numbers, contrary to previous reports. All of the previously known structures were extended to much higher spin and their high-frequency band crossings are interpreted within the framework of the cranked shell model.

Nuclear Data Sheets, 2004

The deep-inelastic reaction studies (1999As05, 1997Le11, and 1997Le10) extended the yrast band of 175 Yb to the Jπ= 41/2-level at 4426 keV. New studies (1994Mi04) of 175 Yb βdecay have provided significantly more precise γ-ray intensities. New data (2002Ro17 and 1998To14) from the alpha decay of 179 Tl have been used for tentatively assigning spin and parity to 1 7 5 Au ground and first-excited states. Tentative assignment of 1 7 5 Hg g.s. is adopted from 1 7 6 Tl proton decay (2004Ke06).

Physical Review C, 2014

Linear polarization and angular correlations of γ-rays depopulating excited states in the neutron deficient nucleus 94 44 Ru50 have been measured, enabling firm spin-parity assignments for several excited states in this nucleus. The deduced multipolarities of strong transitions in the yrast structure were found to be mostly of stretched M1, E1 and E2 types and, in most cases, in agreement with previous tentative assignments. The deduced multipolarity of the 1869 keV and the connecting 257 keV and 1641 keV transitions indicates that the state at 6358 keV excitation energy has spinparity 12 − 1 rather than 12 + 3 as proposed in previous works. The presence of a 12 − 1 state is interpreted within the framework of large-scale shell model calculations as a pure proton-hole state dominated by the π(p −1 1/2 ⊗ g −5 9/2 ) and π(p −1 3/2 ⊗ g −5 9/2 ) configurations. A new positive-parity state is observed at 6103 keV and is tentatively assigned as 12 + 2 . The 14 − 1 state proposed earlier is reassigned as 13 − 4 and was interpreted as being dominated by neutron particle-hole core excitations. The strengths of several E1 transitions have been measured and are found to provide a signature of core-excited configurations.

Physical Review C, 2000

Time-correlated, particle-tagged ␥ spectroscopy of the stable nucleus 179 Hf was undertaken with incomplete fusion reactions initiated by beams of 9 Be and 7 Li incident on targets of 176 Yb. Intrinsic and rotational states above the three-quasiparticle K ϭ25/2 Ϫ , T 1/2 ϭ25 day isomer, 179 Hf m2 , are reported. The rotational band based on 179 Hf m2 has g K Ϫg R values that are consistent with the previously suggested 9/2 ϩ 2 ͓7/2 ϩ ,9/2 Ϫ ͔ configuration assignment. A value of g R ϭ0.34(5) was derived for the collective g factor of 179 Hf m2 , which is considerably higher than that found for the 9/2 ϩ ground state. The difference is consistent with a reduction of the proton pairing strength due to blocking in the K ϭ25/2 Ϫ 2 configuration. A number of 3 2 five-quasiparticle configurations were identified, the highest of which is an yrast K ϭ43/2 ϩ , T 1/2 ϭ15(5) s isomer. It decays to an yrast K ϭ39/2 Ϫ state, which in turn decays to a rotational band based on a K ϭ33/2 Ϫ state. The K ϭ33/2 Ϫ state decays to the rotational band associated with 179 Hf m2 . Semiempirical calculations reproduce the excitation energies of the three-and five-quasiparticle states above 179 Hf m2 to within ϳ200 keV. The calculations predict that the lowest seven-quasiparticle state will arise from a 5 2 configuration with K ϭ47/2 Ϫ , which is just beyond the maximum spin accessible with the reactions employed here.

Nuclear Physics A, 1991

High-spin states in '73 OS have been studied by yy-coincidence measurements following the 's6Nd(32S, 5n)'730s reaction. Additional information has also been extracted from the reaction '44Sm(3'S, 2pn)"'Os. Four main sequencies have been identified as the two signature branches of the bands built on the [642]$+ and [523]$-Nilsson states. The band features have been analysed within the framework of the cranked shell model. The positive-parity band provides evidence for a v(i,3,2)2 crossing at low frequency and a r(h,,,,)' and/ or r(hg,?)' crossing at higher frequency. In the negative-parity band the upbend starts at relatively low frequency indicating, presumably, an early v(i,,,z)' alignment. There is evidence for another two band crossings possibly due to u(i,,,,)' alignment of a different configuration and a high frequency proton alignment as in the positive-parity band. B(Ml)/ B(E2) ratios have also been extracted in both bands to deduce further information on the detailed structure of the bands. NUCLEAR REACTIONS '46Nd(3ZS, 5n), E = 166 MeV; '44Sm(3'S, 3pn). E = 163 MeV; E measured yy-coin. '730s deduced levels, J, T, configurations, alignments, E(Ml)/B(E2J ratios.

Nuclear Physics A, 1982

A6strad: The level structure of rssSm has been studied with various spectroscopic techniques using the (a, 2ny) reaction . Seven rotational bands were identified up to spin values of 9 to 14A, viz. the ground{tate band, theß-and y-bands, and four negative-panty bands (NPB's). In the ß-band a beginning of backhanding or upbending was observed at I=14A. Two of the NPB's are based upon collective states; the lowest can be interpreted as an aligned octupole band, the other one show: two-quasiparticle charaderiatia at high spin. The properties of the other NPB'a are consistent with K' = S-and K`= 7-two-quaaiperticle configurations of the bandheada. At high spin these bands are strongly mixed. Excitation energies for all bands with a collective bandhesd, as well as B(El) and B(E2) branching ratios and (for the ß-band) X(EO/E2) ratios, were compared with IBA calculations .

Physical Review C, 1980

High-spin states in ' 'Tl, excited through the ' 'Ta("0, 7n) and "'Ta(' 0,5n) reactions, were studied using in-beam y-ray spectroscopic techniques. Excitation functions, activity spectra, y-ray angular distributions, and multidimensional coincidences were measured. The strongly Coriolis-distorted mh9/2)(vl]3/2 twoquasiparticle band already known in the heavier ' " ' Tl isotopes has also been found in this case based on an I = 8 isomeric state at 250.6 keV above the known long-lived 7+ level. Trends already noted in the other Tl isotopes and also predicted by two-quasiparticle plus-rotor model calculations are confirmed thus reinforcing such a theoretical description. NUCLEAR REACT&ONS &si Ta~180, xny), E =105-125 MeV; Ta(O, xny~~& =95-105 MeV. measured E I o(E E 0) y-y coin 9 Tl. levels deduced J, m', Tf/2 Natural target. Ge(Li) detectors.

Physical review, 1970

Nuclear Physics A, 1995

Excited levels of the strongly-deformed odd-odd nucleus 166Tm, populated by the 165Ho(a,3ny) reaction, were investigated using standard in-beam y-ray spectroscopy, including measurements of a few conversion electron lines, and by high-resolution curved-crystal spectroscopy. A level scheme consisting of 178 transitions among 6 well-developed and 4 partial rotational bands is proposed. Level spins and parities were determined and the results were interpreted in the framework of the Nilsson model by comparison with predictions. The Gallagher-Moszkowski splitting for 5 + the {~r½ + [411 ] 4-v~ [642] } configuration was determined to be 245(20) keV. An anomalous signature splitting was observed for the {*r 7+ [404] + v 5+ [642] }K" = 6 + configuration.

Nuclear Physics A, 1996

The 34S + a system has been studied both experimentally and theoretically. Excitation functions of the 34S(o~, y)38Ar reaction have been measured over the alpha bombarding energy range E~ = 3.4-4.4 MeV. The low background provided by the 100% enriched (implanted) target allowed one to observe 10 new resonances, some of them attributed previously to the 32S contamination of the target. Decay schemes, spin-parity values, reduced electromagnetic transition probabifities and resonance strengths have been determined. A semimicroscopic algebraic 34S + a cluster model has been used to describe the new resonances together with the low-lying states of the 38Ar nucleus. This analysis indicates that the J-~ = 1-resonances may not be good candidates for the first state of a K ~ = 0-band predicted to start in the Ex "~ 10-11 MeV region.

Physical Review C, 2011

Excited states in the neutron-deficient nucleus 167 Ta were studied through the 120 Sn( 51 V,4n) reaction. Twelve rotational bands have been observed and the relative excitation energy of each sequence is now known due to the multiple interband connections. Several quasineutron alignments were observed that aided in the quasiparticle assignments of these bands. The resulting interpretation is in line with observations in neighboring nuclei. Trends in the wobbling phonon energy seen in 161,163,165,167 Lu and 167 Ta are also discussed and particle-rotor model calculations (assuming constant moments of inertia) are found to be inconsistent with the experimental data.

arXiv: Nuclear Experiment, 2019

The level scheme of the compound $^{153}$Sm nucleus formed via the $^{152}$Sm($n_{th}$,$\gamma$) reaction is studied by using the $\gamma-\gamma$ coincidence spectrometer at Dalat Nuclear Research Institute, Vietnam. All the gamma cascades, which correspond to the decays from the compound state to 12 final levels of 0 ($\frac{3}{2}^+$), 7.535 ($\frac{5}{2}^+$), 35.844 ($\frac{3}{2}^-$), 90.875 ($\frac{5}{2}^-$), 126.412 ($\frac{1}{2}^-$), 127.298 ($\frac{3}{2}^-$), 182.902 ($\frac{5}{2}^-$), 321.113 ($\frac{3}{2}^+$), 404.129 ($\frac{1}{2}^-$), 405.470 ($\frac{3}{2}^-$), 414.924 ($\frac{1}{2}^+$), and 481.088 ($\frac{3}{2}^+$) keV, have been measured. A total number of 386 cascades corresponding to 576 gamma transitions has been detected. Among these cascades, 103 primary gamma transitions together with their corresponding intermediate levels and 299 secondary transitions have been determined. In addition, 29 primary gamma transitions, 42 intermediate levels, and 8 secondary transit...

Physical Review C, 2008