共查询到20条相似文献,搜索用时 13 毫秒
1.
F. Dubbers L. Funke P. Kemnitz G. Winter S. Elfström Th. Lindblad C. G. Lindén 《Zeitschrift für Physik A Hadrons and Nuclei》1978,287(2):165-169
The doubly-odd nucleus176Ta is investigated by means of in-beamγ-ray spectroscopy techniques using the reactions (α, 3n), (d, 2n) and (p, n). Life-time measurements in thens-region yield low-lying isomeric states withT 1/2=13±1 ns and 30.5±1 ns, while measurements in the ms-region show the existence of a 1.1±0.1 ms isomeric state. A rotational sequence, withK=5 or 6 for the band-head, is also observed. 相似文献
2.
J. Davidson M. Davidson M. Debray G. Falcone D. Hojman A. J. Kreiner I. Mayans C. Pomar D. Santos 《Zeitschrift für Physik A Hadrons and Nuclei》1986,324(3):363-364
High spin states in176, 178Re have been studied using in-beam γ and e? spectroscopy techniques through heavy ion induced fusion reactions. A ΔI=2 rotational band of doubly decoupled type has been identified in each isotope. 相似文献
3.
Y.-J. Ma Y.-Z. Liu H.-B. Sun S. Wen S.-G. Zhou H. Zheng H.-T. Yang J.-D. Huo X.-G. Wu C.-X. Yang 《The European Physical Journal A - Hadrons and Nuclei》1998,2(1):21-23
Three new bands in 174Ta have been identified by using the 160Gd(19F,5n) reaction at beam energies of 87 MeV and 96 MeV. Nilsson configurations are assigned to these bands. In the 9/2−[514]p+5/2−[512]n band, the AB neutron crossing occurs at a rotational frequency of 0.30 MeV. This is indicative of the disappearance of the
evidence for a reduction in neutron pair correlations.
Received: 30 March 1998 相似文献
4.
《Nuclear Physics A》1998,632(2):229-274
The high spin structure of the nucleus 178W has been studied following the 170Er(13C,5n) reaction. Many previously unidentified rotational bands are seen based on high-K, 2-, 4-, 6- and 8-quasiparticle structures, some of which are isomeric. The excitation energies of the multi-quasiparticle bandheads are compared with BCS calculations, including residual interactions. The bands show substantial increases in moments-of-inertia with increasing quasiparticle number. These are examined in terms of pairing blocking. The effect of blocked pairing is also taken into account in the calculation of g-factors, which supports the configuration assignments. The Kπ = 25+, 8-quasiparticle band forms the yrast line from its bandhead upwards. This bandhead is a 220 ns isomer whose decay is strongly hindered, compared to the decay of the four- and six-quasiparticle structures. 相似文献
6.
High spin rotational levels in 173Ta are populated in the 165Ho(12C, 4n)173Ta and 175Lu(α, 6n)173Ta reactions. The de-excitation γ-ray cascades are studied with Ge(Li) detectors. The rotational bands, which are built on the +(404), +(402), ?(514) and ?(541) intrinsic states, are identified up to high spin values. A state, interpreted as a three quasi-particle state with a probable spin of is located at 1713 keV. Its half-life is about 100 ns. The behaviour of the moment of inertia of each rotational band versus the rotational frequency is compared with that of the doubly even core. 相似文献
7.
Low-lying intrinsic states and their associated rotational bands have been identified in 177Os and 179Os. They are the mixed i neutron states and the ?[521] states in 177Os and 179Os, as well as the ?[512] state in 177Os and the ?[514] state in 179Os. The ? sta is assumed to be the ground state, the other intrinsic states giving rise to isomers. The in-band decay properties of the ?[514] band, and the i bands show the effect of mixing. In the rotational bands in 177Os a low frequency backbending anomaly is observed but no anomaly is observed in the i. band. In 179Os the i band does backbend but at a higher frequency than in the yrast bands of the even neighbours. The systematics of the backbending frequencies, and the effects of blocking, are discussed. The rotation aligned angular momentum is deduced, and a comparison made between the i bands and the s-bands in the even neighbours. The results broadly support the identification of the s-bands with the aligned (i)2 configuration. 相似文献
8.
I. Alfter E. Bodenstedt W. Knichel J. Schüth R. Vianden 《Zeitschrift für Physik A Hadrons and Nuclei》1996,355(1):363-376
g-factors of rotational states in176Hf and180Hf were measured with the twelve detector IPAC-apparatus of our laboratory [1]. The natural radioactivity 3.78·1010y176Lu and the 5.5 h isomer180mHf were used which populate the ground-state rotational bands of176Hf and180Hf. The integral rotations ofγ-γ directional correlations in strong external magnetic fields and in static hyperfine fields of (Lu→Hf)Fe2 and HfFe2 were observed. The following results were obtained: $$\begin{array}{l} ^{176} Hf: g\left( {4_1^ + } \right) = + 0.334\left( {38} \right) \\ ^{180} Hf: g\left( {2_1^ + } \right) = + 0.305\left( {14} \right) \\ g\left( {4_1^ + } \right) = + 0.358\left( {43} \right) \\ {{ g\left( {6_1^ + } \right)} \mathord{\left/ {\vphantom {{ g\left( {6_1^ + } \right)} {g\left( {4_1^ + } \right)}}} \right. \kern-\nulldelimiterspace} {g\left( {4_1^ + } \right)}} = + 0.95\left( {12} \right) \\ \end{array}$$ . The hyperfine field in (Lu→Hf)Fe2 was calibrated by observing the integral rotation of the 9/2? first excited state of177Hf populated in the decay of 6.7d177Lu. Theg-factor of this state was redetermined in an external magnetic field as $$^{177} Hf: g\left( {{9 \mathord{\left/ {\vphantom {9 {2^ - }}} \right. \kern-\nulldelimiterspace} {2^ - }}} \right) = + 0.228\left( 7 \right)$$ . Finally theg-factor of the 2 1 + state of176Hf was derived from the measuredg(2 1 + ) of180Hf by use of the precisely known ratiog(2 1 + ,176Hf)/g(2 1 + ,180Hf) [2] as $$^{176} Hf: g\left( {2_1^ + } \right) = + 0.315\left( {30} \right)$$ . 相似文献
9.
I. Alfter E. Bodenstedt W. Knichel J. Schüth R. Vianden 《Zeitschrift für Physik A Hadrons and Nuclei》1976,355(4):363-376
g-factors of rotational states in 176Hf and 180Hf were measured with the twelve detector IPAC-apparatus of our laboratory [1]. The natural radioactivity 3.78 · 1010y 176Lu and the 5.5 h isomer 180mHf were used which populate the ground-state rotational bands of 176Hf and 180Hf. The integral rotations of γ-γ directional correlations in strong external magnetic fields and in static hyperfine fields of (Lu → Hf)Fe2 and HfFe2 were observed. The following results were obtained: The hyperfine field in (Lu → Hf)Fe2 was calibrated by observing the integral rotation of the 9/2? first excited state of 177Hf populated in the decay of 6.7d 177Lu. The g-factor of this state was redetermined in an external magnetic field as Finally the g-factor of the 2 1 + state of 176Hf was derived from the measured g(2 1 + ) of 180Hf by use of the precisely known ratio g(2 1 + , 176Hf)/g(21 +, 180Hf) [2] as 相似文献
10.
T.R. Saitoh N. Hashimoto G. Sletten R.A. Bark S. Törmänen M. Bergström K. Furuno K. Furutaka G.B. Hagemann T. Hayakawa T. Komatsubara A. Maj S. Mitarai M. Oshima J. Sampson T. Shizuma P.G. Varmette 《The European Physical Journal A - Hadrons and Nuclei》1998,3(3):197-199
High-spin states in 181Ta have been studied via the 176Yb(11B,α2n) reaction at 52 MeV using the PEX array and at 57 MeV using the NORDBALL array, with α-particle detection. The previously
known, Kπ=(7/2)+ ground state band and Kπ=(9/2)− band have been extended to spins (29/2)+ and (31/2)−, respectively. Two new one-quasiparticle bands, the Kπ=(5/2)+ band built on the known (5/2)+ isomer and a Kπ=((1/2)−) band have been observed. Two other rotational bands with three-quasiparticle structure, Kπ=(15/2)− and ((19/2)+ with π(7/2)[404]ν2(1/2)[510](9/2)[624] and π(9/2)[514]ν2(1/2)[510](9/2)[624] configurations, respectively, have been newly observed. The half-life of the Kπ=((19/2)+) bandhead which decays to the head of the (15/2)− band has been measured to be 140(36) ns. However, transitions from the ((19/2)+) state to the (15/2)− band have not been observed.
Received: 26 August 1998 相似文献
11.
The one-quasiparticle bands in the N = 99 nucleus 171Hf have been identified to spins of about using (heavy ion, xn) reactions. The moments of inertia of these bands are consistent with the absence of backbending in the N = 98 core nucleus. The half-life of the intrinsic state was measured as 63.6 ns. The strength of the transition is discussed. Two three-quasiparticle isomers with spins and parities have been identified and their suggested configurations are a neutron added to the 6+ and 8? two-quasiproton states of the core. The moment of inertia of a rotational band based on the isomer supports this suggestion, and shows the effect of partial rotation alignment of the neutron. 相似文献
12.
M. A. Riley D. E. Archer J. Simpson T. B. Brown J. Döring J. W. Holcomb G. D. Johns T. D. Johnson T. Petters J. Pfohl S. L. Tabor O. N. Tekyi-Mensah P. C. Womble V. A. Wood 《Zeitschrift für Physik A Hadrons and Nuclei》1993,346(4):319-320
The [402]5/2 bands in177Ta which are identical to the neighboring even-even176Hf groundstate band have been extended to higher angular momentum. These bands in the two nuclei are seen to diverge from each other in the region of the first i13/2 neutron alignment. The lower observed crossing frequency for the [402]5/2 bands indicates a lower deformation for these bands compared to176Hf. Extensions to theh
9/2 [541]1/2 yrast band are also reported.Special thanks to D.C. Radford, It. MacLeod, W.T. Milner and R. Books for their invaluable software support. Thanks also to F.K. McGowan and R. Darlington for their help with the targets. This work was supported by the National Science Foundation and the State of Florida and by the UK Science and Engineering Research Council. MAR and JS acknowledge the receipt of a NATO Collaborative Research Grant. 相似文献
13.
High-spin yrast and non-yrast states have been identified in 176Os, 178Os and 180Os using (16O, xn) reactions, and γ-ray techniques. Band crossing anomalies are observed in each of the positive-parity yrast bands. The magnitude of these anomalies decreases with decreasing neutron number, an effect attributed to the change in the moment of inertia of the ground state rotational bands. A 23 ns isomer, predominantly Kπ = 7?, is identified at 1930 keV in 180Os. The configuration of this isomer is discussed on the basis of the properties of its rotational band. Negative parity, odd and even spin, sideband sequences are observed in each isotope. Their relationship to rotation-aligned octupole and 2-quasiparticle bands is discussed from their excitation energies, band spacings, and decay properties. Detailed calculations for Coriolis mixed bands are carried out for the likely 2-quasiproton and 2-quasineutron configurations. An anomaly observed at spin 17 in the odd-spin negative-parity sequence in 180Os is attributed to a band crossing with a fourquasiparticle configuration. 相似文献
14.
E. Vigezzi T. Døssing M. Matsuo K. Yoshida P. Bosetti A. Bracco S. Frattini B. Herskind S. Leoni 《Zeitschrift für Physik A Hadrons and Nuclei》1997,358(2):207-211
We present shell model calculations for warm rotating nuclei, combining the cranked Nilsson mean field and a residual surface-delta two-body interaction. The model is used to describe the transition from the region of well-defined rotational bands into the region dominated by rotational damping, and the results are in overall agreement with the experimental findings. 相似文献
15.
The signature splittings in Kπ = 1 +: 7 /2[404] π?9 /2[624] ν, Kπ = 0?: 9 /2[514] π?9 /2[624] ν bands of 180Ta and Kπ = 0?: 7 /2[404] π?7 /2[503] ν, Kπ = 1?: 5 /2[402] π?3 /2[512] ν, Kπ = 1+: 7 /2[404] π?9 /2[624] ν bands of 182Ta are analysed within the framework of two-quasiparticle rotor model. The phase as well as magnitude of the experimentally observed signature splitting in Kπ = 1+ band of 180Ta, which could not be explained in earlier calculations, is successfully reproduced. The conflict regarding placement of a 12 + level in Kπ = 1 +: 7 /2 +[404] π?9 /2 +[624] ν ground-state rotational band of 180Ta is resolved and tentative nature of Kπ = 0?: 7 /2[404] π?7 /2[503] ν, Kπ = 1+: 7 /2[404] π?9 /2[624] ν bands observed in 182Ta is confirmed. As a future prediction for experimentalists, these two-quasiparticle structures observed in 180Ta and 182Ta are extended to higher spins. 相似文献
16.
Nearly-spherical nuclei in three mass regions have recently been observed to exhibit rotational-like features. We have identified
almost 80 such bands; largest number (43) lie in the lead region. Most of these bands are assigned oblate multi-quasiparticle
configurations. Their interpretation in terms of ‘magnetic rotation’ does not allow for signature splitting in these bands.
We have however found signature splitting as well as signature inversion in many bands. We apply the two-quasiparticle plus
rotor model to understand the occurrence of signature splitting vis-a-vis the role of ‘shears mechanism’ in these bands. 相似文献
17.
Multi-quasiparticle states and rotational bands in neutron-rich erbium isotopes have been investigated by the configuration-constrained pairing-deformation-frequency self-consistent total-Routhian-surface (TRS) method with particle-number-conserved pairing. Specifically, the recently observed Kn=4-bands in 168,170,172 Er have been found to experience a configuration change in our calculation. Some other multi-quasiparticle states with uncertain configuration assignments have been reinvestigated by calculating their collective rotations. The configuration-constrained TRS calculation can reproduce experimental data consistently. 相似文献
18.
T. Seo A. -M. Schmitt H. Ahrens J. P. Bocquet N. Kaffrell H. Lawin G. Lhersonneau R. A. Meyer K. Shizuma K. Sistemich G. Tittel N. Trautmann 《Zeitschrift für Physik A Hadrons and Nuclei》1984,315(2):251-253
The nucleus103 Nb 62 has been studied through the ß? decay of the fission product103Zr at LOHENGRIN and JOSEF. The energies of the lowlying levels and the γ transitions indicate rotational bands based on the Nilsson proton configurations [422 5/2+] [303 5/2?] and [301 3/2?] at 0, 164 and 248 keV, respectively. The measured half-lives of (4.7±0.5) ns and (2.0±0.6) ns of the levels at 164 and 248 keV are consistent with the Nilsson-model estimates including pairing. 相似文献
19.
R. -D. Herzberg S. Moon S. Eeckhaudt P. T. Greenlees P. A. Butler T. Page A. V. Afanasjev N. Amzal J. E. Bastin F. Becker M. Bender B. Bruyneel J. F. C. Cocks I. G. Darby O. Dorvaux K. Eskola J. Gerl T. Grahn C. Gray-Jones N. J. Hammond K. Hauschild P. -H. Heenen K. Helariutta A. Herzberg F. Hessberger M. Houry A. Hürstel R. D. Humphreys G. D. Jones P. M. Jones R. Julin S. Juutinen H. Kankaanp?? H. Kettunen T. L. Khoo W. Korten P. Kuusiniemi Y. LeCoz M. Leino A. -P. Lepp?nen C. J. Lister R. Lucas M. Muikku P. Nieminen M. Nyman R. D. Page T. Page J. Pakarinen A. Pritchard P. Rahkila P. Reiter M. Sandzelius J. Saren Ch. Schlegel C. Scholey Ch. Theisen W. H. Trzaska J. Uusitalo A. Wiens H. J. Wollersheim 《The European Physical Journal A - Hadrons and Nuclei》2009,42(3):333-337
In-beam gamma-ray and conversion electron spectroscopic studies have been performed on the 253 No nucleus. A strongly coupled rotational band has been identified and the improved statistics allows an assignment of the band structure as built on the $\ensuremath 9/2^-[734]_{\nu}$ ground state. The results agree with previously known transition energies but disagree with the tentative structural assignments made in earlier work. 相似文献
20.
The nucleus 30 65 Zn was studied using the 52Cr(16O, 2pn)65Zn reaction at a beam energy of 65 MeV. The level scheme is extended up to an excitation energy of 10.57 MeV for spin-parity (41/2?) with several newly observed transitions placed in it. 相似文献