115768171
Preliminary Results of Mono‐energetic Electron Beams from a Laser‐plasma Accelerator Driven by 200 TW Femto Second Pulses
Relativistic mono‐energetic electron beams have been demonstrated by worldwide laser‐plasma accelerator experiments in the range of a few tens TW. Laser‐plasma accelerator experiment has been carried out with 200TW, 30fs Ti:Sapphire laser pulses focused on helium gas‐jets with F/8.7 optics. Intense mono‐energetic electron beams have been produced in the energy range of 30 to 150 MeV by controlling plasma length and density precisely. Images of Thomson scattering and fluorescence side scattering from plasma indicate highly relativistic effects such as a long self‐channeling and filamentation as well as energetic electron deflection and intense backward Raman scattering. Preliminary results of the first laser‐plasma accelerator experiment in the range of 200TW femto second pulses are presented.
125624266
beta-delayed proton decays near the proton drip line
We briefly reviewed and summarized the experimental study on {beta}-delayed proton decays published by our group over the last 8 years, namely the experimental observation of {beta}-delayed proton decays of nine new nuclides in the rare-earth region near the proton drip line and five nuclides in the mass 90 region with N{approx}Z by utilizing the p-{gamma} coincidence technique in combination with a He-jet tape transport system. In addition, important technical details of the experiments were provided. The experimental results were compared to the theoretical predictions of some nuclear models, resulting in the following conclusions. (1) The experimental half-lives for {sup 85}Mo, {sup 92}Rh, as well as the predicted 'waiting point' nuclei {sup 89}Ru and {sup 93}Pd were 5-10 times longer than the macroscopic-microscopic model predictions of Moeller et al. [At. Data Nucl. Data Tables 66,131(1997)]. These data considerably influenced the predictions of the mass abundances of the nuclides produced in the rp process. (2) The experimental assignments of spin and parity for the drip-line nuclei {sup 142}Ho and {sup 128}Pm could not be well predicted by any of the nuclear models. Nevertheless, the configuration-constrained nuclear potential-energy surfaces calculated by means of a Woods-Saxon-Strutinsky method could reproduce the assignments. (3) Themore » ALICE code overestimated by one or two orders of magnitude the production-reaction cross sections of the nine studied rare-earth nuclei, while the HIVAP code overestimated them by approximately one order of magnitude.« less
99999919
Spin assignments for the beta-delayed proton precursors Ho-142 and Pm-128
The previous experimental data on beta-delayed proton decays of Ho-142 and Pm-128 were compared with a statistical-model calculation. As a result, the spins of both Ho-142 and Pm-128 were assigned as 5, 6, or 7. Nuclear potential-energy surface calculations were performed using the Woods-Saxon-Strutinsky method. The calculated results support the assignments of 7(-) to Ho-142 and 6(+) to Pm-128.
119784397
beta-delayed proton decay of the proton drip-line nucleus Ho-142
Unknown beta -delayed proton precursor Ho-142 was synthesized in the reaction Cd-106 (Ca-40.p3n) and identified for the first time using proton-gamma coincidence measurements in combination with a helium-jet fast tape-transport system. Its beta -delayed proton spectrum was observed. The half-life of Ho-142 was determined to be 0.4+/-0.1 s. According to the estimated relative branching ratios to the final states in the daughter nucleus, the ground-state spin of Ho-142 could be assigned as 6, 7, or 8.
33137217
Exponential growth, superradiance, and tunability of a seeded free electron laser.
Exponential growth and superradiance regimes in a high-gain free electron laser (FEL) are studied in this paper for both a seeded FEL and a Self-Amplified Spontaneous Emission (SASE) FEL. The results are compared to the earlier superrdaince theory and the recent experimental observation. The influence of an initial energy chirp along the electron bunch on the superradiance mode is explored for the first time. With a short seed to increase the initial seed bandwidth, a tunable seeded FEL is possible.
119291775
Nuclear Shell Structure Evolution Theory
The Self-similar-structure shell model (SSM) comes from the evolution of the conventional shell model (SM) and keeps the energy level of SM single particle harmonic oscillation motion. In SM, single particle motion is the positive harmonic oscillation and in SSM, the single particle motion is the negative harmonic oscillation. In this paper a nuclear evolution equation (NEE) is proposed. NEE describes the nuclear evolution process from gas state to liquid state and reveals the relations among SM, SSM and liquid drop model (DM). Based upon SSM and NEE theory, we propose the solution to long-standing problem of nuclear shell model single particle spin-orbit interaction energy . We demonstrate that the single particle motion in normal nuclear ground state is the negative harmonic oscillation of SSM[1][2][3][4] 
Key words: negative harmonic oscillation, nuclear evolution equation, self-similar shell model
119519117
Energy dependence of jet quenching and lifetime of dense matter in high-energy heavy-ion collisions
Suppression of high p{sub T} hadron spectra in high-energy heavy-ion collisions at different energies is studied within a perturbative QCD parton model incorporating medium-induced parton energy loss. The p{sub T} dependence of the nuclear modification factor R{sub AA}(p{sub T}) is found to depend on both the energy dependence of the parton energy loss and the power-law behavior of the initial jet spectra. The high p{sub T} hadron suppression at {radical}(s)=62.4 GeV and its centrality dependence are studied in detail. The overall values of the modification factor are found to provide strong constraints on the lifetime of the dense matter.
120456002
HEAVY ION THEORY: QCD AND MATTER IN EXTREMIS
Nuclear matter is predicted to undergo a phase transition and become a plasma of quarks and gluons (QGP) at high temperature and density. Recent experimental results from high-energy heavy-ion collisions at the Relativistic Heavy-ion Collider (RHIC) indicate the production of a strongly interacting quark-gluon matter with fluid-like properties. I will discuss some expected features of QCD at high temperature and density, theoretical interpretations of experimental observations and challenges in unraveling some of the basic properties of dense matter in the strongly interacting regime.
119280465
Characterizing Temporal Structure of the Relativistic Electron Bunch
Using proper beam energy chirp and the undulator detuning effect, we propose a modified optical replica synthesizer scheme to characterize the temporal structure of a relativistic electron bunch, which predicts a 100-fs temporal resolution in numerical simulation. The proof of principle experiment demonstrates a peak current of 9 A and a slice energy spread of about 0.5 keV for the uncompressed electron beam of the Shanghai Deep UV Free Electron Laser Facility.