Excited Stated in ^207Rn

Excited states ^207Rn are investigated via the^196Pt(^16O,Sn)^207 Rn reaction at beam energies from 85 to 95 MeV using techniques of in-beam γ-ray spectroscopy.Measurements of γ-ray excitation function,x-γ and γ-γ-t conincidences are performed with ten BGO(AC) HPGe detectors.Based on these measurements,a level scheme of ^207Rn,including 17 γ-rays and 18 levels,is established.Spins for most of the levels are proposed according to the measured DCO ratios.The level struccture is compared with a weak-coupling calculation using the interaction energies extracted from neighbouring nuclei.     

Level Structure in ^190Tl

The high-spin states of very neutron-deficient doubly odd nucleus ^190T1 have been investigated via the ^160Gd(^35C1, 5n)^190T1 reaction by using techniques of in-beam γ-ray spectroscopy. Measurements of X-γ and γ-γ-t coincidences were performed with 12BGO(AC)HPGe detectors. Based on the gated spectra, γ-γ coinci-dence relationships, γ ray energy sums, γ ray relative intensities and the previous work, the level scheme     

Decay of the 67-μs Isomer in ^142Pm

Excited states in ^142pm are investigated via the ^12sTe(^19F, 5n)^142pm reaction at beam energies from 75 to 95 MeV by using techniques of in-beam γ-ray spectroscopy. Measurements of γ-ray excitation function, X-γ and γ-γ-t coincidences are performed with 10 BGO(AC)HPGe detectors. Decay of the previously known 67-μs isomer in     

Lifetimes of Excited Levels in ^131Ce

The fusion-evaporation reaction ^116Sn (^19F, p3n)^131 Ce at projectile energy of 95 MeV is used to populate high spin states in ^131Ce. The de-exciting γ-rays are detected in γ-γ coincidence measurement with Compton-suppressed BGO-HPGe detectors. Level lifetimes of ^131 Ce were determined by using the Doppler shift attenuation method.The experimental results indicate that collectivity of ^131 Ce is reduced relative to that of ^130Ce and it follows that deformation decreases with increase of the neutron number on the basis of systematic comparison of transition quadrupole moments for the light cerium isotopes.     

Observation of High-j Two-Quasiparticle Bands in Odd-Odd ^174Re

High spin states in ^174Re have been investigated via the ^152Sm （^27 Al, 5nγ） ^174Re reaction. Gamma-ray excitation functions, x-γ and γ-γ coincidences have been measured. Two rotational bands built on the πh9/2 × vi13/2 and πh11/2 × vi13/2 configurations have been identified and extended up to high-spin states. The relative spin and parity of the band levels have been unambiguously fixed due to observations of several inter-band transitions. Both the bands show the low-spin signature inversion, which is consistent with systematic expectations for the high-j two-quasiparticle bands in the A = 170 mass region.     

Large Decay Rate Variation of ^7Be in Pd and Au

Platinum and gold have the similar crystal structure but different electronic affinities, as well as different effective electron densities near the implanted ions. Both the differences favour larger decay rate of ^7 Be in Pd than that in Au. We measured the variation of the decay rate of ^7Be implanted in Pd and Au host materials. We have found that the decay rate of ^7 Be in Pd is larger than that in Au by 0.8%.     

Experimental Observation of High Spin States in ^135La Nucleus

High spin states of ^135La have been experimentally studied by ^128Te(^10B, 3n)^135La reaction. The ^10B beam was provided by the tandem accelerator laboratory in the University of Tsukuba, Japan. Based on the γ-γ coincidence relationships, relative intensities and ADO ratios, a level scheme of ^135La has been established.     

Gound State Properties of Nuclei in ^295118 α-Decay Chain

The properties of nuclei belonging to the α-decay chain of superheavy element ^295118 have been studied in the framework of axially deformed relativistic mean field （RMF） theory with the parameter set of NL-Z2 in the blocked BCS approximation. Some ground state properties such as binding energies, deformations, and α-decay energies Qα have been obtained and agree well with those from finite-range droplet model （FRDM）. The single-particle spectra of nuclei in ^295118 α-decay chain show that the shell gaps present obviously nucleon number dependence. The root-mean-square （rms） radii of proton, neutron and matter distributions change slowly from ^283112 to ^295118 but dramatically from ^279110 to ^283112, which may be due to the subshell closure at Z = 110 in ^279110. The α-decay half-lives in 295118 decay chain are evaluated by employing the cluster model and the generalized liquid drop model （GLDM）, and the overall agreement is found when they are compared with the known experimental data. The α-decay lifetimes obtained from the cluster model are slightly larger than those of GLDM ones. Finally, we predict the α-decay half-lives of Z=118, 116, 114, 112 isotopes using the cluster model and GLDM, which also indicate these two models can corroborate each other in studies on superheavy nuclei. The results from GLDM are always lower than those obtained from the cluster model.     

Structures of ^17F and ^17O, ^17Ne and ^17N in the Ground State and the First Excited State

The structures of two couples of mirror nuclei ^17F and ^17O, ^17Ne and ^17N in the ground state and in the first excited state are investigated using the relativistic mean-field approach. Two-proton halo in ^17Ne in the first excited state and in the ground state and two-neutron halo in ^17N in the first excited state are suggested.Meanwhile, one-proton halo in ^17F in the first excited state and one-neutron halo in ^17O in the first excited state are also suggested. The skin structure appears in ^17F and ^17N in the ground state.     

High-spin Band Structure in Odd-odd ^170Re

High-spin states in doubly odd ^170Re nucleus have been investigated for the first time, through in-beam γ-ray spectroscopy, following the ^142Nd(^32S, 1p3n γ) ^170Re reaction at 166 McV bombarding energy. The ^32 Sbeam was provided by the tandem accelerator at the China Institute of Atomic Energy, Bcijing. The ^142 Ndtarget is an enriched metallic foil of about 2.2 mg/cm^2 thickness with a 7.0 mg/cm^2 Pb backing to stop the recoiling nuclei. Measurement of X-γ, and γ-γ coincidences wcrc performed with 12 BGO(AC)HPGc detectors. A total of 150 million coincidence events wcrc recorded. The detector energies and cfficicncics wcrc calibrated     

Cross-Correlation of Excitation Functions for Different Fragments and Different Scattering Angles in ^27Al（^19F,x）y Reactions

Excitation functions have been measured for different projectile-like fragments produced in ^27Al（^19F, x ）y reactions at incident energies from 110. 25 to 118. 75 Me V in 250 ke V steps. Strong cross section fluctuations of the excitation functions are observed. The cross-correlation coefficients of the excitation functions for different atomic number Z and for different scattering angle θcm have been deduced. These coefficients are much larger than the statistical theoretical calculated ones. This indicates that there are strong correlations between different exit channels in the dissipative heavy ion collision of ^27Al（^19F, x）y.     

Negative Parity Bands and Signature Splitting Inversion in ^80Rb

High spin states in ^80Rb were studied via the ^65Cu ^19F, ^66Zn ^180 and ^68Zn ^160 reactions. The 75-MeV ^19F,76-MeV ^180 and 80-MeV ^160 beams were provided by the CIAE HI-13 Tandem accelerator and the JAERI Tandem accelerator. The prompt γ-γ coincidence and the directional correlation from oriented nuclei (DCO)were measured by the detector arrays in CIAE and JAERI. Twenty-three new states with 28 new transitionshave been assigned to ^80Rb. The states were observed up to spins of 20^ and 22^- in the α= 0 branch for thepositive and negative parity yrast bands respectively. The negative parity non-yrast bands were significantlyextended up to spins of 22^- and 15^-. The band crossings with frequencies 0.51 MeV and 0.61 MeV in the α= 0cascade were observed for the first time. The signature splitting was observed in both negative parity bands. Thesignature inversions at spins of about 7h and 15h were observed.     

High-spin States in Odd-odd ^140Pr Nucleus

The high-spin level structures of doubly odd nucleus ^140Pr have been investigated by means of the ^130Te(^14N,4n)^140Pr reaction. The ^14N beam was obtained from the HI-13 tandem accelerator of China Institute of Atomic Energy, Beijing. The target is an enriched ^130Te metallic foil of 1.67mg/cm^2 thickness with a 10.37mg/cm^2 Pb backing. Measurements of γ-ray singles, γ-γ-t coincidences and γ-ray excitation function were performed with twelve BGO(AC)HPGe detectors. Based on detailed analysis of γ-γ coincidence relationships, γ-ray     

Ds（0^±） Meson Spectroscopy in Gaussian Sum Rules

Masses of the Ds（0^±） mesons are investigated from a view-point of ordinary light-heavy system in the framework of the Gaussian sum rules, which are worked out by means of the Laplacian transformation to the usual Borel sum rules. Using the standard input of QCD non-perturbative parameters, the corresponding mass spectra and couplings of the currents to the Ds（0^±） mesons are obtained. Our results are mDs（0-） = 1.968±0.016±0.003 GeV and mDs（0＋） = 2.320 ±0.014 ± 0.003 GeV, which are in good accordance with the experimental data, 1.969 GeV and 2.317 GeV.     

Resonant Continuum in the Relativistic Mean－Field Theory

Energies,widths and wave functions of the single-particle resonant continuum are determined by solving scattering states of the Dirac equation with proper asymptotic conditions for the continuous spectrum in the relativistic mean-field theory.The relativistic regular and irregular Coulomb wave functions are calculated numerically.The resonance states in the continum for some closed-or sub-closed-shell nucleus in Sn-isotopes,such as ^114Sn,^116Sn,^118Sn,and ^120Sn are calculated.Results show that the S-matrix method is a reliable and straightforward way in determining energies and widths of resonant states.     

Largely Deformed Dinuclear System Formed in ^19F ＋^27Al Dissipative Collision

Excitation functions are measured for different charge products of the ^19F＋^27AI reaction in the laboratory energy range 110.25-118.75MeV in steps of 250keV at θlab=57°,31° and -29°. The coherence rotation angular velocities of the intermediate dinuclear systems formed in the reaction are extracted from the cross section energy autocorrelation functions. Compared the angular velocity extracted from the experimental data with the ones deduced from the sticking limit, it is indicated that a larger deformation of the intermediate dinuclear system exists.     

Triaxial interaction effect in the structure of ^148-158Sm

The structures of ^148-158Sm are studied in the frame of the interacting boson model. Attention is given to the triaxial interaction, and it is found that the triaxial interaction plays an important role in the detailed structure of this isotopic chain. The potential surfaces of these nuclei are also studied and the shapes of them are analysed. And it is found that though the triaxial interaction plays an important role in these nuclei, there are no stable triaxial shapes in the low-lying structures of these nuclei.     

Femtosecond laser-inscribed waveguides in Nd3^＋：y3^＋：SrF2 crystals

Optical waveguides are fabricated in Nd3^＋：y3^＋：SrF2 crystals by a 1-kHz femtosecond laser using the double-line approach. Waveguides with different separations （10, 15, and 20 μm） between two consecutive optical breakdown tracks are produced, and their optical performances are explored by end-fire coupling to 780-and 532-nm lasers. Propagation loss of the waveguide with 20-pro separation is estimated. The micro- photohmlinescence and micro-Raman spectra indicate that the original fluorescence and lattice structure of the Nd3^＋：y3^＋：SrF2 crystals are well preserved in the waveguide. Therefore, the obtained waveguide structures are promising candidate for application in integrated waveguidc lasers.     

Unusual Threshold Anomaly in the ^6Li＋^208Pb System

The angular distributions of elastic scattering for the ^6Li ＋^208Pb system have been measured at several energies around the Coulomb barrier. The parameters of optical potential are extracted by means of a phenomenological optical model analysis. It is found that the real and imaginal potentials show a pronounced energy dependence. The behaviour of the potential at the nearly especially sub-barrier energies in the ^6Li＋^208Pb system is quite different from the results of some previous reports observed in other systems, such as ^19F＋^208Pb and ^16O＋^208Pb. This unusual threshold phenomenon indicates that breakup channel is strongly coupled with the elastic channel and has obvious effects on optical potential.     

Identical Bands and Alignment in ^193,194Tl

The microscopic mechanism of the identical bands in odd-odd nucleus ^194Tl and its neighbour odd-A nucleus ^193Tl are investigated using the particle-number conserving method with monopole and quadrupole pairing interaction. It is found that the blocking effect plays an important role in the variation of moments of inertia (J^(1) and J^(2)) with rotational frequency for the superdeformed bands and identical bands. The alignment of 194T1 bands with respect to the ^193Tl(1) band used as a reference is also discussed.