118385441
High-Brightness Electron Accelerator Injection System and Experimental Studies of Laser-Induced Explosive Electron Emission.
120010712
Laser-Seeded Free-Electron Lasers at the NSLS
The National Synchrotron Light Source (NSLS) has a long tradition of research and development in accelerator physics and light source technologies. Over the past two decades, the NSLS has made many pioneering contributions to the development of storage-ring-based light sources, such as the Chasman-Green lattice, global orbit feedback systems, and in-vacuum insertion devices. Even from the earliest days of the NSLS, the staff also had started to explore the potential of free-electron-laser (FEL)-based light sources, leading to some seminal work on the theory of self amplified spontaneous emission (SASE) FELs [1,2].
16712339
Intersecting branes and adding flavors to the Maldacena-Nunez background
Following a proposal in ref. [3], we study adding flavors into the Maldacena-Nunez background. It is achieved by introducing spacetime filling D9-branes or intersecting D5'-branes into the background with a wrapping D5-brane. Both D9-branes and D5'-branes can be spacetime filling from the 5D bulk point of view. At the probe limit it corresponds to introducing non-chiral fundamental flavors into the dual = 1 SYM. We propose a method to twist the fundamental flavor which has to involve open string charge. It reflects the fact that coupling fundamental matter to SYM in the dual string theory corresponds to adding an open string sector.
119118563
Transverse momentum broadening in semi-inclusive deep inelastic scattering at next-to-leading order
Within the framework of higher-twist collinear factorization, transverse momentum broadening for the final hadrons in semi-inclusive deeply inelastic $e+A$ collisions is studied at the next-to-leading order (NLO) in perturbative QCD. Through explicit calculations of real and virtual corrections at twist-4, the transverse momentum weighted differential cross section due to double scattering is shown to factorize at NLO and can be expressed as a convolution of twist-4 nuclear parton correlation functions, the usual twist-2 fragmentation functions and hard parts which are finite and free of any divergences. A QCD evolution equation is also derived for the renormalized twist-4 quark-gluon correlation function which can be applied to future phenomenological studies of transverse momentum broadening and jet quenching at NLO.
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.
53617759
STATUS OF POLARIZATION CONTROL EXPERIMENT AT SHANGHAI DEEP ULTRAVIOLET FREE ELECTRON LASER
A polarization control experiment by utilizing a pair of crossed undulators has been proposed for the Shanghai deep ultraviolet free electron laser test facility. Numerical simulations indicate that, with the electromagnetic phaseshifter located between the two crossed planar undulators, fully coherent radiation with 100 nJ order pulse energy, 5 picoseconds pulse length and circular polarization degree above 90% could be generated. The physical design study and the preparation status of the experiment are presented in the paper.
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.