g-factor measurements in stable Hg isotopes

The g-factor of the first 2⁺ state in¹⁹⁸Hg,²⁰⁰Hg and²⁰²Hg has been measured using the thin foil Transient Field technique. The values were calibrated to the known g-factor of the first 5/2⁻ state in¹⁹⁹Hg. The levels were Coulomb excited by 217 MeV nickel ions with gadolinium acting as ferromagnetic medium. The obtained values are rather constant and contradict a previously observed dip at²⁰⁰Hg. Two other g-factors have been remeasured in¹⁹⁹Hg.     

Study of magnetic-rotation in 82Rb by g-factor measurements

Magnetic rotation in 82Rb has been investigated for the first time by g-factor measurement of intra-band states of the magnetic-rotational band built on the 11-state. The g-factors were measured by a TMF-IMPAD method and calculated by a semi-classical model of independent particle angular momentum coupling assumption. The g-factors and deduced shears angles decrease with the increasing of spin along the band, illustrating a step-by-step alignment of the valence protons and neutrons. The rapid alignment of the valence neutrons leads to a decrease of g-factors. The present results vividly reveal the shears mechanism of magnetic rotation.     

Proton alignment in 82Sr investigated by g-factor measurements

The proton alignment in 82Sr has been investigated by the g-factor measurements of the ground state rotational band levels up to spin I = 8+. The g-factors were measured by a transient-magnetic-field ion implantation perturbed angular distribution method. The obtained g-factors increase with the increasing of spin along the band and clearly show the g9/2 proton alignment that starts at I = 6+.     

Unnatural-parity states in 44 21Sc23

The neutron-deficient nucleus ⁶⁸As was populated at high spin in two experiments using the reaction ⁴⁰Ca(³²S, 3pn) at beam energies of 105 and 95 MeV. A self-supporting and a gold-backed, highly enriched ⁴⁰Ca target were used. Gamma rays were detected with the EUROBALL array, combined with the charged-particle detector array EUCLIDES and the Neutron Wall. The ⁶⁸As level scheme was considerably extended, especially at negative parity and many previous spin-parity assignments were confirmed or rejected. The total-Routhian-surface (TRS) calculations find shape coexistence and softness for the negative- and positive-parity states, respectively.     

Lifetime measurements in166Er

The lifetimes of five states in the ground band, from spin 6⁺ up to spin 14⁺, and of all even states in the gamma band up to spin 12⁺, have been measured in¹⁶⁶Er using the recoil distance method. The reduced electric quadrupole transition probabilities have been determined from the measured lifetimes using previously measured branching ratios, and the mixing between the ground band and theγ-band has been studied. The transitional electric quadrupole moments for the ground band and theγ-band have been deduced and are discussed.     

Lifetime measurements in 148Gd

Lifetimes of excited states in ¹⁴⁸Gd were measured using the recoil distance method with a plunger device coupled to the EUROBALL Ge detector array. The differential decay curve method in coincidence mode allowed the unambiguous determination of lifetimes of more than 20 excited states. The obtained transition strengths are in good agreement with the shell model calculations. The effect of the Z = 64 subshell closure on the B(E2 : 2⁺ → 0⁺) reduced strengths above the N = 82 magic number is discussed.-1 Received: 14 November 2002 / Accepted: 4 February 2003 / Published online: 29 April 2003     

Lifetime measurements in25Mg

We present analytic solutions of the Eilenberger equations for the low-frequency Green's functions corresponding to those quasiparticles whose trajectories pass near the center of an isolated vortex. Using these results we find that for type II superconductors in the temperature rangeT _c ?T?T _c ²/ε_F the order parameter and the supercurrent near the vortex center increase over a lengthξ ₁～ξ _BCS T/T _c (ξ _BCS=BCS coherence length) and that the density of states at the Fermi surface isN ₀ 2π ³ ξ _BCS ² /3 In (ξ _BCS/ξ ₁). The results can be reproduced with the Bogoliubov equations for the elementary excitations. It is shown that this peculiar behavior is connected with the low-lying bound states in the vortex core. ForT? _c ²/ε _F one hasξ ₁～k _F ^?1.     

Electric field controlled g-factor in parabolic well determined by transport measurements

The Shubnikov de Haas oscillations in parabolic well are studied in the tilted magnetic field. The electric field displaces the electron wave function along Z-axis and leads to the strong variation of the average bare g-factor in such system. From the measurements of the filling factor ν_c at which the spin gap collapse occurs, we deduce the total Zeeman energy, which consists of the bare Zeeman energy and exchange-correlation term. By investigating of the variation of ν_c in tilted field we reliably extract the bare g-factor as a function of the gate voltage.     

Lifetime measurements of lithiumD-states

We report lifetime measurements of the 1s ² 3d ² D, 1s ²4d ² D, and 1s ²2p ² P states of lithium. The results τ=14.5±0.7 ns, τ=31.0±1.0 ns, and τ=27.9±1.0 ns respectively were obtained by time resolved detection of the resonance fluorescence following pulsed laser excitation.     

Lifetime measurements and calculations in La I

Radiative lifetime measurements have been performed, with a time-resolved laser-induced fluorescence technique, for 20 odd-parity levels of La I belonging to the configurations 5d ²6p, 5d6s6p and 4f5d6s. The new results are compared with the few experimental data available in the literature and with theoretical calculations including configuration interaction effects. The agreement theory-experiment is generally satisfying but discrepancies are observed for some levels emphasizing the difficulty to get a reliable theoretical model in such a heavy and complex neutral element.Received: 26 January 2004, Published online: 22 June 2004PACS: 32.70.Cs Oscillator strengths, lifetimes, transition moments - 42.62.Fi Laser spectroscopy     

Cross sections for production of 43Sc, 44Sc, and 46Sc isotopes in the 45Sc + 3He reaction

Reactions ⁴⁵Sc(³He, αn)⁴³Sc, ⁴⁵Sc(³He, α)⁴⁴Sc, and ⁴⁵Sc(³He, 2p)⁴⁶Sc, resulting from the irradiation of scandium targets with a beam of ³He ions with energy from 5 to 24 MeV, are investigated in experiments on the U120M cyclotron of the Nuclear Physics Institute (Rez, Czech Republic). The activation technique is used to find the yield of the produced Sc isotopes. The induced γ activity in the targets is measured using a high-resolution HPGe detector. Despite the low binding energy of ³He and positive reaction Q values, which leads to formation of the ⁴⁴Sc and ⁴⁶Sc isotopes, the behavior of the excitation functions for the formation of these isotopes differs from the behavior of the excitation function for deuterons. Scandium-44 formation cross sections reach their maximum at the reaction Coulomb barrier. This is because not only ⁴⁴Sc but also a stable ⁴He nucleus is formed in the reaction.     

Cross sections of 43Sc, 44Sc, 46Sc isotopes formed in the 45Sc + 3He reaction

Reactions ⁴⁵Sc(³He, αn)⁴³Sc, ⁴⁵Sc(³He, α)⁴⁴Sc and ⁴⁵Sc(³He, 2p)⁴⁶Sc in the ³He energy range of 5 to 24 MeV are investigated in experiments performed with a ³He ion beam during the irradiation of U-120M cyclotron scandium targets. Activation is used to determine the yield of nascent Sc isotopes. The γ activity induced in targets is measured using a high-resolution HPGe detector. The character of the excitation function changes during the formation of these ions and differs from the excitation functions for deuterons, despite the low bond energy of ³He and the positive values of the Q reactions leading to the formation of ⁴⁴Sc and ⁴⁶Sc isotopes. The cross sections of ⁴⁴Sc formation reach their maximum value at the Coulomb barrier of the reaction, due to the stable ⁴He nucleus that accompanies the formation of ⁴⁴Sc. The contribution from different reaction mechanisms to the cross sections of ⁴³Sc, ⁴⁴Sc, and ⁴⁶Sc isotope formation are considered.     

Excitation functions for 44Sc, 46Sc, and 47Sc radionuclides produced in the interaction of 45Sc with deuterons and 6He

Experimental excitation functions are presented for ⁴⁵Sc(d, p)⁴⁶Sc, ⁴⁵Sc(d, t)⁴⁴Sc, ⁴⁵Sc(⁶He, ⁵He*)⁴⁶Sc and ⁴⁵Sc(6He, α)⁴⁷Sc reactions at projectile energies near the Coulomb barrier. The obtained excitation functions for reactions ⁴⁵Sc(d, p)⁴⁶Sc and ⁴⁵Sc(⁶He, ⁵He*)⁴⁶Sc have similar behavior and have a maxima near the Coulomb barriers of these reactions. The compilation of the available experimental data, obtained at deuteron- and ⁶He-energies near the Coulomb barrier, showed that the values of the cross sections at the maxima of the excitation functions obtained in (d, p) reactions and the reactions for one-neutron pickup from the ⁶He projectiles have a different Z-dependence.     

Lifetime andg-factor measurements in136Nd

We report on the measurement of lifetimes and magnetic moments of yrast states in¹³⁶Nd. Lifetimes in the 5–100 ps range were measured via the recoil distance Doppler shift method applied to the¹¹⁰Pd(³⁰Si, 4n) reaction at 121 MeV beam energy. Magnetic moments were deduced from the integral Larmor precessions measured after recoil implantation into a magnetized nickel foil (IMPAC), via the⁷⁶Ge(⁶⁴Ni, 4n) reaction. The measured g factors g(12⁺)=g(10⁺)= +1.03(24) clearly indicate h_11/2 proton alignment.     

Magnetooptic measurements of the cyclotron mass and g-factor of light holes in GaAs

An emission line appearing in the hot-luminescence spectrum of GaAs at a frequency shifted from the laser line by the cyclotron energy of light holes is observed and investigated. Analysis of the magnetooscillations of the intensity of this line shows that the line is due to the recombination of a photoexcited electron and a light hole after the hole undergoes energy relaxation between Landau levels. The dependence of the cyclotron mass and g factor of light holes on the hole energy was measured directly and a very strong nonparabolicity of the valence band of GaAs, several times greater than the theoretical estimates, was observed. Pis’ma Zh. éksp. Teor. Fiz. 64, No. 11, 766–771 (10 December 1996)     

Lifetime measurements in99Sr and100Zr

The lifetime of the first excited state in⁹⁹Sr has been determined by the delayed γ-γ coincidence method. The value of t_/2=0.58(9) ns corresponds to a deformation parameter ß=0.38(4). The deduced z> value confirms the previously proposed ν[411]3/2 Nilsson assignment for the⁹⁹Sr ground state. In addition, lifetime values for the 2⁺ (t_1/2=0.40(8) ns) and 0⁺ (t_1/2=5.36(23) ns) states in¹⁰⁰Zr are obtained, which deviate from older measurements and indicate a larger deformation of ß=0.39(4).     

Lifetime measurements in70Se and72Se

Mean lives and limits of lifetimes have been determined for some ten mostly yrast states in⁷⁰Se, by means of the recoil distance Doppler shift technique. The states were excited in the reaction⁴⁰Ca(³⁶Ar,α2p) at 115 MeV resp. the reaction⁵⁸Ni(¹⁴N,pn) at 39 MeV beam energy. The systematic decrease ofB(E2) values along the the ground band transitions indicates a band crossing consistent with theγ-ray energies. Effects of continuum feeding times in both reactions are being discussed. The lifetimes of the lowest three yrast transitions in⁷²Se have been remeasured by means of the reactions⁴⁰Ca(³⁶Ar,4p) and⁶⁰Ni(¹⁴N,pn).     

Study of magnetic-rotation in ~(82)Rb by g-factor measurements

Magnetic rotation in ⁸²Rb has been investigated for the first time by g-factor measurement of intra-band states of the magnetic-rotational band built on the 11- state. The g-factors were measured by a TMF-IMPAD method and calculated by a semi-classical model of independent particle angular momentum coupling assumption. The g-factors and deduced shears angles decrease with the increasing of spin along the band, illustrating a step-by-step alignment of the valence protons and neutrons. The rapid alignment of the valence neutrons leads to a decrease of g-factors. The present results vividly reveal the shears mechanism of magnetic rotation.