New high spin level scheme of ~(87)Sr

High spin states of the odd-A87Sr were populated by the fusion-evaporation reaction82Se(9Be,4n)87Sr at a beam energy of 46 MeV. Excited levels of87 Sr have been extended up to an excitation energy of 7.4 MeV at spin31/2. The coupling of a g9/2neutron hole to the yrast states of the88 Sr core can account for the low-lying states in87 Sr. The structure of the higher spin states is discussed by analogy with those of the neighboring odd-A N =49isotones and possible configurations are proposed.     

Structure of high spin states in 112In

The high spin states of ¹¹²In have been populated via the ¹¹⁰Pd(⁷Li,5n)¹¹²In reaction with a beam energy of 50 MeV. By analyzing the γ-γ coincidence relations and DCO ratios of γ transitions,A new level scheme of ¹¹²In including seventy-four new gamma transitions and six new bands up to the excitation energy of 6.8 MeV has been presented.     

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 g_9/2 proton alignment that starts at I=6⁺.     

Cooling and Trapping 88Sr Atoms with 461nm Laser

We report the experimental realization of a ^88Sr magneto-optical trap （MOT） operating at the wavelength of 461 nm. The MOT is loaded via a 32 cm long spin-flip type Zeeman slower which enhances the MOT population by a factor of 22. The total laser power available in our experiment is about 300mW. We have trapped 1.6 × 10^8 ^88 Sr atoms with a 679nm and 707nm repumping laser. The two repumping lasers enhance the trap population and trap lifetime by factors of 11 and 7, respectively. The ^88 Sr cloud has a temperature of about 2.3 mK, measured by recording the time evolution of the absorption signal.     

Measurements of g-Factor of Rotational Band States in 82Sr

The g-factors of the positive parity rotational states up to spin I = 8^＋ for the ground state band in even-even nuclei S2Sr have been measured by a transient-magnetic-field ion implantation perturbed angular distribution method. The experimentally measured 9-factors increase with the increasing spin along the band and show that the g9/2 proton aligns only and the alignment starts from I =6^＋. The measured g-factors also indicate that the nuclei ^82Sr gain their spins by the quasi-proton alignment at higher spin.     

Simultaneous Magneto-Optical Trapping of Fermionic ^40K and Bosonic ^87Rb Atoms

We report on simultaneous magneto-optical trapping of fermionic ^40K and bosonic 87Rb atoms. This trap is the first step towards quantum degenerate fermi gas ^40K. Laser lights for the two-species magneto-optical trap （MOT） are generated from diode lasers and tapered amplifier. The enriched ^40K dispenser is utilized in the experimental setup. We obtain up to 10^7 -10^8 ^40K and 10^8 -10^9 ^87Rb atoms respectively in the steady-state single-species MOT.     

High spin band structure in 139Nd

High-spin states in ¹³⁹Nd nucleus have been reinvestigated with the reaction ¹²⁸Te (¹⁶O, 5n) at a beam energy of 90 MeV. The level scheme has been expanded with spin up to 47/2 h. At the low spin states, the yrast collective structure built on the νh_{11 / 2}^－1 multiplet shows a transitional shape with γ≈32° according to calculations of the triaxial rotor-plus-particle model. Three collective oblate bands with γ~－60° at the high spin states were identified for the first time. A band crossing is observed around hω~0.4 MeV in one oblate band based on the 25/2^－ level.     

Quantum Degenerate Fermi--Bose Mixtures of 40K and 87Rb Atoms in a Quadrupole-Ioffe Configuration Trap

We report on the attainment of quantum degeneracy of 40^K by means of efficient thermal collisions with the evaporatively cooled 87^Rb atoms. In a quadrupole-Ioffe configuration trap, potassium atoms axe cooled to 0.5 times the Fermi temperature. We obtain up to 7.59 × 10^5 degenerate fermions 40^K.     

新同位素175Er

简介首次合成新核素１７5Ｅｒ及对其衰变纲图测定的实验方法和实验结果． the synthesis and γ decay scheme of new isotope175Er is reported for the first time.The related experimental process and main results are represented briefly also.     

High spin states in neutron-rich 106Tc nucleus

The high spin states of the neutron-rich odd-odd ¹⁰⁶Tc nucleus have been reinvestigated by observing prompt γ-rays from the spontaneous fission of ²⁵²Cf. A previously known collective band is confirmed and expanded, and a new collective band is newly identified. Several levels in previous report in ¹⁰⁶Tc are reexamined and they belong to the members of a band in ¹⁰⁷Tc. The total Routhian surface (TRS) calculations show that the ¹⁰⁶Tc has triaxial shape. The spins and parities as well as the configurations for these bands have been tentatively assigned according to the analysis of the angular momentum alignments.     

New Neutron-Rich Nuclide 185Hf

New neutron-rich nuclide ¹⁸⁵Hf has been identified for the first time.The ¹⁸⁵Hf was produced via the ¹⁸⁶W(n,2p)¹⁸⁵Hf reaction by 14MeV neutron irradiation of natural metallic tungsten powder and separated by radiochemical methods.The identification of ¹⁸⁵Hf was based on the observation of decay γ-ray of its daughter ¹⁸⁵Ta.A half-life of 3.5±0.6min was determined for ¹⁸⁵Hf by fitting the measured growth and decay curve of the 177.59keV γ-ray which is the strongest decay γ-ray of ¹⁸⁵Ta.In addition,a new γ-ray of 164.5±0.5keV was found and assigned to ¹⁸⁵Hf.     

New Neutron-Rich Isotope 208Hg

The new neutron-rich isotope ²⁰⁸Hg has been identified for the first time from the reaction products in fully-stopping thick ^nat.Pb target bombarded by 30MeV/u ¹²C beam provided by the Heavy Ion Research Facility in Lanzhou.Assignment of the nuclide ²⁰⁸Hg was based on the measurements of the deacy γ energy and halflife of its daughter ²⁰⁸Ti,which was grown up with ²⁰⁸Hg β-deacy.The half-life of ²⁰⁸Hg β-deacy was determined to be 42+23－12 min.The average production cross section of ²⁰⁸Hg over the incident energy region from Coulomb barrier to 30MeV/u is found to be 1.1±0.5μb.     

Angular Distribution of the 12C(6He, 7Li)11B Reaction

Angular distribution of the ¹²C(⁶He,⁷Li)¹¹B transfer reaction is measured with a secondary ⁶He beam of 36.4MeV for the first time. The experimental angular distribution is well reproduced by the distorted-wave Born approximation (DWBA) calculation. The success of the present experiment shows that it is feasible to measure one-nucleon transfer reaction on a light nucleus target with the secondary beam facility of the HI-13 tandem accelerator at China Institute of Atomic Energy (CIAE), Beijing.     

Identification of New Isotope 238Th

Unreported heavy neutron-rich nuclide ²³⁸Th has been produced via a multinucleon transfer reaction by 60MeVIu ¹⁸0 ions bombardment of natural uranium.Thorium was radiochemically separated from the mixture of uranium and reaction products. ²³⁸Pa as a daughter nucleus of ²³⁸Th has been identified according to the growth and decay of ²³⁸Pa γ rays which has been observed. The half-life of ²³⁸Th was determined to be (9.4 + 2.0) min. At the same time, a new γ ray of (89.0 + 0.3) keV with T_1/2= (8.9 + 1.5)min was found in the γ spectrum gated with the K_α1, X ray of Pa and assigned to ²³⁸Th decay based on the measurements of its transition energy and the half-life.

     

Radial Expansion Flow in Reactions of 40Ca+58Fe and 40Ca+58Ni

By means of using an isospin-dependent Boltzmann-Langevin equation which includes isospin-dependent symmetry energy, Coulomb energy, isospin-dependent nucleon-nucleon cross sections, Pauli blocking, and initialization, the radial expansion flow of reaction systems ⁴⁰Ca+⁵⁸Ni and ⁴⁰Ca+⁵⁸Fe at 53, 100, 150, and 200 MeV/u in the central collisions were studied. It has shown that the more neutron rich system exhibits smaller radial expansion flow. It was found that the neutron rich system had smaller threshold energy which may provide a new method to determine the isospin dependent nuclear equation of state from calculated result and linear fitting result.     

A Three-Body Model of 11Li,14Be and 17B

The nuclei ¹¹Li,¹⁴Be and ¹⁷B are considered as three-body systems composed of the N=2Z core and two outside neutrons.The core-neutron and neutronneutron interactions are assumed to be the attractive exponential potentials.It has been shown that the three-body system can have a bound state although any two constituents of the system cannot have a bound state. The experimental data of the binding energy and extraordinarily large matter root-mean-square radius can be explained in the frame of the three-body model.     

Optical Potential Parameters for Halo Nucleus System ^6He＋^12C from Transfer Reaction ^11B（^7Li, ^6He）^12C

The optical potential parameters for the halo nucleus system ^6He＋^12C are extracted from fits to the measured angular distributions of ^11B（^7Li, ^6He）12C reaction at energies of 18.3 and 28.3MeV with distorted-wave Born approximation analysis. The characters of the obtained optical potentiM parameters are basically consistent with the results extracted from the fits to the elastic-scattering angular distributions in the literature.     

New band structures in 107Ag

High spin states in ¹⁰⁷Ag are studied via the ¹⁰⁰Mo(¹¹B, 4n)¹⁰⁷Ag reaction at an incident beam energy of 60 MeV. Prompt γ-γ coincidence and DCO ratios are measured by the detector arrays in CIAE. The level scheme has been updated and a new negative band belonging to ¹⁰⁷Ag is identified. The new negative side band has been constructed and its configuration is tentatively assigned to πg_9/2 νh_11/2(g_7/2/d_5/2).     

Level scheme in 160Tm towards complete high-spin structure

High-spin states of ¹⁶⁰Tm have been studied through the ¹⁴⁶Nd(¹⁹F, 5n) reaction at a beam energy of 102 MeV. The previously known πh_11/2⊙νi_13/2 yrast band and πh_11/2⊙νh_9/2 side band are confirmed, and several low-lying levels are observed. A 4-quasiparticle band feeding into the yrast band based on the πg_7/2⊙νh_9/2⊙νi_13/2² is suggested. Other two bands are observed and assigned to be based on the πd_3/2⊙νi_13/2 and πg_7/2⊙νi_13/2 configurations, respectively.     

新重丰中子同位素239Pa的合成

本文简述了新重丰中子同位素２３９Ｐａ的首次合成和鉴别,并测定其半衰期为１０６±３０ｍｉｎ． This paper reports that the new heavy neutron-rich isotope 239Pa has been observed for the first time and its half life has been determined to be 106±30min.