High-spin spectroscopy of162Hf

Excited states in¹⁶²Hf were investigated up to spinI ≈ 38 using the anti-Comptonspectrometer array HERA with 21 detectors. In addition, some information was obtained on¹⁶¹Hf. The analysis of triple coincidences was crucial for the construction of the level schemes. The results are interpreted within the framework of the cranked shell model and are compared to neighbouring isotopes and isotones, showing Fermi level and deformation effects. The systematic behaviour of the band crossings in the Hf isotopes and theN=90 isotones is discussed.     

High-spin states in165Hf

High-spin states in¹⁶⁵Hf, populated in the¹³⁰Te(⁴⁰Ca, 5n) reaction, were investigated using the Berkeley HERA -ray spectrometer array. The previously known level scheme of¹⁶⁵Hf is appreciably extended. Intrinsic configurations, band crossing frequencies and aligned angular momenta are interpreted within the frame-work of the cranked shell model. It is suggested that the alignments of the second neutron pair and of the first proton pair in¹⁶⁵Hf occur at 0.44 MeV and 0.48 MeV, respectively. The systematic trend of these alignment frequencies for the Hf isotopes and for theN=93 isotones is discussed.One of us (EMB) acknowledges a fellowship from the Hanns-Seidel Foundation. This work was supported by the Director, Office of Energy Research, Division of Nuclear Physics of the Office of High Energy and Nuclear Physics of the U.S. Department of Energy (Contract DE-AC03-76SF00098) and by the Bundesminister für Forschung und Technologie BRD (Contract 06 BN 181).     

High-spin states in odd-odd 168Lu

High-spin states in the odd-odd ¹⁶⁸Lu nucleus, populated in the ¹⁵⁴Sm(¹⁹F,5n) reaction at a beam energy of 96 MeV, were investigated using in-beam γ-ray spectroscopy techniques. The BC neutron crossing in the yrast band, based on πg _7/2[404]7/2⁺⊗νi _13/2[642]5/2⁺ configuration, occurs at ħω= 0.31 MeV. The two side bands, based on πh _11/2[514]9/2⁻⊗νi _13/2[642]5/2⁺ and πh _9/2[541]1/2⁻⊗νi _13/2[642]5/2⁺ configurations, show anomalous signature-splitting and signature-inversion in the first one, to occur at ħω= 0.24 MeV. A moderately delayed BC-crossing is anticipated in the second one. Received: 15 June 1998 / Revised version: 11 January 1999     

High-spin states in odd-odd 168Lu

High-spin states of odd-odd ¹⁶⁸Lu were observed up to 18ħ for the first time using the ¹⁵⁹Tb(¹³C, 4nγ)¹⁶⁸Lu reaction at E _13C= 58.5 MeV. γ-γ coincidence, E _γ singles, excitation function, and the DCO ratios were measured. Two rotational bands with signature splitting were populated, among which the lower-energy band is identified as π 7/2⁺[404] ⊗ν 5/2⁺[642] in view of alignment and energy systematics. Received: 27 October 1997     

168Hf三轴超形变核态的研究

采用TRS方法研究了¹⁶⁸Hf核的三轴超形变核态. 通过位能面计算给出了平衡形变参数, 证实了高自旋态下该核存在三轴不对称性. 通过分析各部分修正能量, 研究了其三轴超形变形成的机制: 主要原因是中子壳修正, 同时高j闯入轨道πi_13/2的形变驱动效应和转动能也起到重要作用.     

High-spin,discrete line spectroscopy of 162Yb and 164Hf and the systematics of N = 92 isotones

The high spin states of ¹⁶²Yb and ¹⁶⁴Hf have been studied using ¹²²Sn(⁴⁴Ca, 4n) and ¹²⁰Sn(⁴⁸Sn(⁴⁸Ti, 4n) reactions respectively. The resulting new level schemes for ¹⁶²Yb and ¹⁶⁴Hf are presented and compared with existing data for ¹⁶⁰Er. The systematic behaviour of these three N = 92 isotones at large angular momentum yields information both on modifications of the single-neutron spectrum of states resulting from the polarisation of the nuclear field and on the single-proton spectrum of states.     

High-spin spectroscopy of 63 31Ga32 and 65 31Ga34

High-spin states in the nuclei ⁶³Ga and ⁶⁵Ga were studied following the reaction ³²S + ⁴⁰Ca at a reaction energy of 125 MeV and using the GASP γ-ray spectrometer in combination with the ISIS charged-particle detector system. In addition to low-lying negative-parity states with single-particle character, rotational-like cascades built on the 9/2⁺ and 19/2^- states have been observed in both nuclei. Sidebands with negative parity in ⁶³Ga and positive parity in ⁶⁵Ga could be established. The experimental results are compared with Total Routhian Surface calculations which describe the nuclei as moderately deformed (β₂≈ 0.25) and γ soft at low rotational frequencies. The highest experimentally observed positive-parity state in ⁶⁵Ga (41/2⁺) is in good agreement with the calculated crossing of the collective band with a non-collective one terminating at this spin. Received: 20 December 2000 / Accepted: 2 May 2001     

Site spectroscopy of Hf doping in Hf-doped LiNbO3 crystals

By means of Raman scattering spectroscopy we determine the site location occupied by Hf ions in photorefractive damage resistant Hf-doped LiNbO₃. At room temperature the two lowest frequency phonons are related to sites B (Nb) and A (Li), and are used to directly probe the dopant ion. For the low concentration range, the Hf ions go into the sites A whereas, for high concentration, Hf ions occupy both sites A and B. Results are compared with data obtained for pure congruent and stoichiometric crystals, and the proposed mechanism of incorporation of Hf ions in the LiNbO₃ lattice explains the threshold in the behaviour of photorefractive properties.     

Properties of even ~(168-178)Hf isotopes using IBM-1 and SEF

The properties of the ground and excited-state(γ-and β-bands) of ~(168-178)Hf nuclei have been studied.The ratio r(I +2/I) and Eγ(I→I-2)/I have been calculated as a function of the spin(I) to determine the groundstate evolution. The results indicate that these isotopes have a rotational property SU(3). The energy levels for the ground-state, γ-and β-bands of ~(168-178)Hf have been calculated using the Interacting Boson Model and Semi Empirical Formula(SEF). The parameters of the best fit to the measured data are determined. The behavior of energy and B(E2) ratios in the ground state band are examined.     

High-spin study of Xe

High-spin states have been populated in ₅₄¹¹⁹Xe via the ⁹⁶Mo(²⁷Al,p3n) reaction at 133 MeV, using the γ-ray spectrometer to record triple γ-ray coincidences. The known level scheme has been significantly extended and several band crossings identified. In particular, the νh_11/2 yrast band has been extended to I^π = (83/2⁻) and shows features which are consistent with those of smooth band termination at high spin. Theoretical results for ¹¹⁹Xe at high spin are discussed within the framework of cranked Nilsson-Strutinsky calculations, together with results for ¹¹⁷Xe.     

High-spin low-spin transition

Hyperfine Interactions - Temperature dependent nuclear inelastic-scattering (NIS) of synchrotron radiation was applied to investigate both spin states of the spin-crossover complex [Fe(tpa)(NCS)2]...     

高自旋同质异能态束流的产生和应用

论述了高自旋同质异能态束流的物理意义.以RINKEN的HSIB为例,简略地叙述了高自旋同质异能态束流的产生、分离、传输及纯化的方法,并对高自旋同质异能态束流诱发核反应中放出的γ射线探测技术进行了论述. The physical motivations with high spin isomer beams were introduced. Taking HSIB of RIKEN as an example, the methods to produce, separate, transport and purify high spin isomer beams were described briefly, and the detection of γ rays emitted from the reactions induced by the high spin isomer beams was presented. Finally, the progress to develope the high spin isomers in the N =83 isotones as second beams was stressed.     

High resolution181Hf TDPAC spectroscopy using fast BaF2-detectors

A high resolution TDPAC setup with four BaF₂ detectors was introduced for measurements in chemical and biological systems. High electric field gradients and large asymmetry parameters could be determined very precisely. The data are compared to previous NaI(Tl) measurements on HfF₄·HF·2H₂O, HfO₂, and¹⁸¹Hf-labelled transferrin.     

High-spin states of145Sm

High-spin states of¹⁴⁵Sm were studied by using the²⁰Ne(¹³⁶Xe, α7n),¹³⁹La (¹⁰B, 4n) and¹³⁸Ba(¹³C,6n) reactions. The decay scheme of a high-spin isomer of¹⁴⁵Sm was established. The excitation energy and the spin-parity of the isomer were determined to be 8.8 MeV and (49/2⁺), respectively. The level scheme was extended up to the (65/2) state at 14.6 MeV. The experimental results were discussed comparing with the deformed independent particle model (DIPM) calculation.     

High-spin isomer in 93Mo

The high-spin states of ⁹³Mo have been studied by a ⁸²Se( ¹⁶O, 5n) ⁹³Mo reaction at a beam energy of 100 MeV using techniques of in-beam -ray spectroscopy. Measurements of -t, --t coincidences, -ray angular distributions and -ray linear polarizations were performed. The high-spin isomer was found as a (39/2^-) state at about 9.7 MeV. The near-yrast states in ⁹³Mo were interpreted using the weak-coupling picture of a d_5/2 neutron to a neutron magic core nucleus ⁹²Mo.     

High-spin states in148Tb

High spin states of¹¹⁷Xe have been investigated by means of in-beam γ-ray spectroscopy using the reaction⁹²Mo(²⁸Si, 2pn) at beam energies of 100 to 120 MeV. The previously known νh_11/2 bands are confirmed and the νg_7/2 favored-signature band is extended up to 47/2⁺, in which two band crossings are observed at ?ω=0.33 and 0.44 MeV, respectively. Two new positive-parity bands have been established, one of which is most likely the νg_7/2 unfavored-signature band. A new transition cascade with irregular level spacings is also observed.     

High-spin states in123Te

The¹⁰Be(¹²C,¹⁴O)⁸He-reaction has been used to study the levels of⁸He. In addition to the known excited state of⁸He at E _x =3.6MeV, withJ ^π=2⁺, three additional states were found at excitation energies of 4.54(25)MeV, 6.03(10)MeV and 7.16(4)MeV.     

High-spin states in121Te

The baryon density calculated at the collision center in relativistic heavy ion collisions is not representative for the density really probed by baryons in the high density collision phase. A decomposition into nucleon- and-resonance densities yields average values of 1.25N/o and 0.25/ ₀ at the time of maximum compression.work supported by GSI and BMFT     

High-spin states in97Tc

The level scheme of⁹⁷Tc was studied by gamma ray spectroscopy using the⁹⁴Zr(⁶Li, 3nγ)⁹⁷Tc reaction. New levels and spins and parities were established.⁹⁷Tc is compared with the neighbouring even-even nucleus and with the results of an IBFM calculation.