Engineering topics

Sun, Z Y

Publications and source records attributed to Sun, Z Y.

9 records

DOE OSTI2011

Mass Measurements of Proton-rich Nuclides at the Cooler Storage Ring at IMP

Recent results and progress of mass measurements of proton-rich nuclei using isochronous mass spectrometry (IMS) are reported. The nuclei under investigation were produced via fragmentation of relativistic energy heavy ions of {sup 78}Kr and {sup 58}Ni. After in-flight separation by the fragment separator RIBLL-2, the nuclei were injected and stored in the experimental storage ring CSRe, and their masses were determined from measurements of the revolution times. The impact of these measurements on the stellar nucleosynthesis in the rp-process is discussed.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2011

Recent experimental results of two-proton correlated emission from the excited states of {sup 17,18}Ne and {sup 28,29}S

Two-proton emissions from the excited states of {sup 17,18}Ne and {sup 28,29}S were investigated by the radioactive beams bombarding on the {sup 197}Au target via the Coulomb excitation. The complete-kinematics measurements were actualized by the stacks of silicon-strip detectors and CsI+PIN array detectors. The invariant mass of final systems as well as the relative momentum, opening angle, and relative energy of the two emitted protons were reconstructed under the framework of relativistic kinematics. The mechanisms of two-proton emission were analyzed in a simple schematic model. With the help of Monte-Carlo simulations, the two protons emitted from the 6.15 MeV excited state of {sup 18}Ne and the excited states around 10 MeV of {sup 29}S, respectively, exhibit prominent features of {sup 2}He decay. While for the other states, no obvious diproton emissions were observed.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2011

Effect of carbon/hydrogen species incorporation on electronic structure of anatase-TiO{sub 2}

The energy band structure and optical properties of C-doped and C/H-codoped anatase TiO{sub 2} are investigated using the first-principles based on density-functional theory. The obtained results indicate that the structure of C/H-codoping is more stable than that of C-doping. For C-doped anatase TiO{sub 2}, the band gap narrowing is small, and the high visible-light catalytic ability originates from the isolated C 2p states above the valence-band maximum. With the same carbon doping level, the C/H-codoping produces significant bandgap narrowing, which leads to higher visible-light photocatalytic efficiency than the C-doping does.

36 MATERIALS SCIENCE↗

DOE OSTI2011

Identification of the {gamma}-vibrational band built on the 11/2{sup -}[505] orbital in {sup 165}Er

Excited states in {sup 165}Er have been populated using the {sup 160}Gd({sup 9}Be, 4n) reaction at beam energies of 42 and 45 MeV. A band consisting of two levels at excitation energies of 1317.6 and 1505.9 keV, both of which decay strongly to the 11/2{sup -}[505] band, is observed and assigned as the {gamma}-vibrational band built on the 11/2{sup -}[505] configuration. In addition, a newly identified level is proposed as a three-quasiparticle state.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2011

Neutron spectroscopic factors of {sup 34}Ar and {sup 46}Ar from (p,d) transfer reactions

Single-neutron-transfer measurements using (p,d) reactions have been performed at 33 MeV per nucleon with proton-rich {sup 34}Ar and neutron-rich {sup 46}Ar beams in inverse kinematics. The extracted spectroscopic factors are compared to the large-basis shell-model calculations. Relatively weak quenching of the spectroscopic factors is observed between {sup 34}Ar and {sup 46}Ar. The experimental results suggest that neutron correlations have a weak dependence on the asymmetry of the nucleus over this isotopic region. The present results are consistent with the systematics established from extensive studies of spectroscopic factors and dispersive optical-model analyses of {sup 40-49}Ca isotopes. They are, however, inconsistent with the trends obtained in knockout-reaction measurements.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2010

Observation of two-{alpha} emission from high-lying excited states of {sup 18}Ne by complete-kinematics measurements

Two-{alpha} emission from high-lying excited states of {sup 18}Ne was studied by complete-kinematics measurements. The {sup 18}Ne beam at the energy of 51.8 MeV/u was bombarding a {sup 197}Au target to populate the excited states via Coulomb excitation. Products of two-{alpha} emission, {sup 10}C-{alpha}-{alpha}, were measured by an array of silicon strip detectors and a CsI + PIN telescope. With the help of Monte Carlo simulations, the experimental results show the characteristics of sequential two-{alpha} emission via {sup 14}O excited states. Sequential two-{alpha} and two-proton emissions from {sup 18}Ne via one-particle daughter states are compared and the distinction of the opening angles of these two modes originates from the difference of the mass ratio of emitted particles to daughter nuclei.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2010

Isospin diffusion and equilibration for Sn+Sn collisions at E/A=35 MeV

Equilibration and equilibration rates have been measured by colliding Sn nuclei with different isospin asymmetries at beam energies of E/A=35 MeV. Using the yields of mirror nuclei of {sup 7}Li and {sup 7}Be, we have studied the diffusion of isospin asymmetry by combining data from asymmetric {sup 112}Sn+{sup 124}Sn and {sup 124}Sn+{sup 112}Sn collisions with those from symmetric {sup 112}Sn+{sup 112}Sn and {sup 124}Sn+{sup 124}Sn collisions. We use these measurements to probe isospin equilibration in central collisions where nucleon-nucleon collisions are strongly blocked by the Pauli exclusion principle. The results are consistent with transport theoretical calculations that predict a degree of transparency in these collisions, but inconsistent with the emission of intermediate mass fragments by a single chemically equilibrated source. Comparisons with quantum molecular dynamics calculations are consistent with results obtained at higher incident energies that provide constraints on the density dependence of the symmetry energy.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2010

Investigation of two-proton emission from excited states of the odd-Z nucleus {sup 28}P by complete-kinematics measurements

An experiment to study exotic two-proton emission from excited levels of the odd-Z nucleus {sup 28}P was performed at the National Laboratory of Heavy Ion Research-Radioactive Ion Beam Line (HIRFL-RIBLL) facility. The projectile {sup 28}P at the energy of 46.5 MeV/u was bombarding a {sup 197}Au target to populate the excited states via Coulomb excitation. Complete-kinematics measurements were realized by the array of silicon strip detectors and the CsI+PIN telescope. Two-proton events were selected and the relativistic-kinematics reconstruction was carried out. The spectrum of relative momentum and opening angle between two protons was deduced from Monte Carlo simulations. Experimental results show that two-proton emission from {sup 28}P excited states less than 17.0 MeV is mainly two-body sequential emission or three-body simultaneous decay in phase space. The present simulations cannot distinguish these two decay modes. No obvious diproton emission was found.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2010

Nuclear physics program at HIRFL

With the commissioning of HIRFL-CSR, HIRFL can provide heavy ion beams with energy covering the range of several MeV/u to 1 GeV/u. In this talk, the experiments on nuclear physics at different energies to be carried out with different experimental setups at HIRFL will be introduced.

43 PARTICLE ACCELERATORS↗