A5027075465- Particle Accelerators and Free-Electron Lasers
- Gyrotron and Vacuum Electronics Research
- Photocathodes and Microchannel Plates
- Particle accelerators and beam dynamics
- Advanced X-ray Imaging Techniques
- Pulsed Power Technology Applications
- Laser-Plasma Interactions and Diagnostics
- Electrostatic Discharge in Electronics
- Radiation Detection and Scintillator Technologies
- Silicon Carbide Semiconductor Technologies
- Superconducting Materials and Applications
- Quantum and electron transport phenomena
- Atmospheric Ozone and Climate
- Integrated Circuits and Semiconductor Failure Analysis
- Electron and X-Ray Spectroscopy Techniques
- Thermal Radiation and Cooling Technologies
- Terahertz technology and applications
Shanghai Advanced Research Institute
2019-2025
Chinese Academy of Sciences
2018-2024
University of Chinese Academy of Sciences
2018
Shanghai Institute of Applied Physics
2018
Xi'an University of Technology
2011-2012
The echo-enabled harmonic generation (EEHG) scheme holds promising prospects for efficiently generating intense coherent radiation at very high harmonics of a conventional ultraviolet seed laser. We report the lasing EEHG free-electron laser (FEL) an extreme (EUV) wavelength with seeded FEL facility, Shanghai soft x-ray FEL. For first time, we have benchmarked basic theory by measuring bunching factor distributions over one octave down to EUV region. Our results demonstrated key advantages...
The spectroscopic techniques for time-resolved fine analysis of matter require coherent X-ray radiation with femtosecond duration and high average brightness. Seeded free-electron lasers (FELs), which use the frequency up-conversion an external seed laser to improve temporal coherence, are ideal providing fully soft pulses. However, it is difficult operate seeded FELs at a repetition rate due limitations present state-of-the-art systems. Here, we report novel self-modulation method enhancing...
The room temperature continuous wave (cw) very-high-frequency (VHF) gun is one of the candidates for electron high-repetition-rate free-electron lasers (FELs). VHF operates with a cathode gradient <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mo>∼</a:mo><a:mn>20</a:mn><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi>MV</a:mi><a:mo>/</a:mo><a:mi mathvariant="normal">m</a:mi></a:mrow></a:math> and an accelerating voltage <d:math...
It is a long-standing challenge for laser technologies to generate intense fully coherent pulses in the x-ray regime. Here, we demonstrate an external seeding mechanism, termed echo-enabled harmonic cascade (EEHC) generating and ultrashort soft pulses. The mechanism uses generation as first stage, producing extreme ultraviolet that seed second stage free-electron (FEL) with high-gain setup. Benefiting from low sensitivity electron-beam imperfections of EEHC, generated high-power nearly...
Abstract Coupler RF kick due to the asymmetric structure caused by coupler, is more likely lead emittance growth in SHINE injector with low beam energy. The calculation of coupler and resulting dilution has been studied detail literature. In this paper, a novel approach provided that lossy material placed on surface superconducting cavity approximate Q 0 TESLA cavity, frequency solver CST used simulate electromagnetic field distribution, which calculate kick, calibrated against results...
Photocathodes based on bialkali antimonides have great potential in the field of high-brightness electron sources. In this paper, influence incident light absorption performance ${\mathrm{K}}_{2}\mathrm{CsSb}$ photocathodes was studied using Monte Carlo simulations. The surface plasmon polaritons (SPPs) were first introduced into employing a nanopattern structure to improve effective and adjust initial distribution photoelectrons. To evaluate effect SPPs photocathode performance,...
The output current characteristics of a high-gain photoconductive semiconductor switch (PCSS) were analyzed under different bias voltages. results indicate that the voltages on discharge regions filament are dynamic, which determines transient characteristics. physical processes anode region influenced by voltage PCSS dominate presents characteristic lock-on or overshoot. quench is determined external circuit and carrier recombination process, resulting in turn-off PCSS.
The authors designed the voltage withstand test of photoconductive semiconductor switch (PCSS) in which electrode gap was 18 mm condition pulsed laser triggered. During experiments, flashover quenching photon-activated charge domain (PACD) has been observed, namely, when occurred, pulse current amplitude semi-insulating GaAs PCSS lower than normal value without and rise time output increased. experiment indicates that characteristics contain information flashover, occurs with discharge PCSS....
Semi-insulating gallium arsenide (GaAs) photoconductive semiconductor switches (PCSS) have great potential for high voltage switching application, however, the utility is restricted by surface flashover which would result in breakdown. In this paper, a model of photo-activated charge wave was proposed based on theory domain (PACD) GaAs PCSS, and moderate suppression PACD formation loading with dielectric material investigated theoretically experimentally. Current as 3.7 kA obtained at 28 kV,...
It is very important to increase the quantum efficiency (QE) and prolong lifetime of photocathode in a variety applications. We have succeeded preparing high QE cesium potassium antimonide (K–Cs–Sb) by K Cs co-evaporation preparation facility. In order better understand effect substrate (photocathode) temperature on performance, preparation, performance degradation, recovery removal are studied detail.
In Recent years, the Cherenkov light radiation transformed from surface plasmon polaritons has been found and proposed for a compact adjustable source. As process is motivated by charged particle beam, characteristics of are not only related with device but can also reflect certain beam. this paper, beam position energy measurement method based on polaritons. Early-stage numerical analytical investigations presented planar structure device.
In order to prepare high-quantum-efficiency semiconductor Cs-Te photocathode which can produce a high-quality electron source, based on the INFN-LASA preparation method, method with Te intermittent, Cs continuous deposition is developed. The quantum efficiency greater than 5% under 265 nm UV irradiation successfully prepared in device of SINAP and SARI, fabrication success rate reaches 100%. As long as chamber vacuum degree better 10<sup>–8</sup> Pa, high be by this will not...
The introduction of the surface plasmon polarizations makes emittance photocathode complicated. In this paper, plasmon-enhanced is analyzed. It first demonstrated that plasmonic near field can increase photocathode. A simulation method has been used to estimate caused by field, and suppression also discussed, both which are significant for design high performance
Flashover severely restricts the development of photoconductive semiconductor switch (PCSS) in high-voltage and high power. This paper reported peculiar phenomenon that current pulse, when flashover occurred, was lower wider than normal value. Based on photon-activated charge domain model mechanism, reason, influence secondary electron emission avalanche output wave, analyzed. The dipole imported to describe critical state where pulse occurred during flashover.
Coupler RF kick due to the asymmetric structure caused by coupler, is more likely lead emittance growth in SHINE injector with low beam energy. The calculation of coupler and resulting dilution has been studied detail literature. In this paper, a novel approach provided that lossy material placed on surface superconducting cavity approximate Q0 TESLA cavity, frequency solver CST used simulate electromagnetic field distribution, which calculate kick, calibrated against results Particle...