A5029444096- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Gyrotron and Vacuum Electronics Research
- Photocathodes and Microchannel Plates
- Advanced X-ray Imaging Techniques
- Superconducting Materials and Applications
- Electron and X-Ray Spectroscopy Techniques
- Radiation Therapy and Dosimetry
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Advanced Radiotherapy Techniques
- Radiation Detection and Scintillator Technologies
- Pulsed Power Technology Applications
- Particle Detector Development and Performance
- Laser-Plasma Interactions and Diagnostics
- Integrated Circuits and Semiconductor Failure Analysis
- Advanced Optical Sensing Technologies
- Radiation Effects and Dosimetry
- Electromagnetic Compatibility and Measurements
- Plant Physiology and Cultivation Studies
- Superconducting and THz Device Technology
- Soybean genetics and cultivation
- Plasma Diagnostics and Applications
- Magnetic confinement fusion research
- Advanced Electron Microscopy Techniques and Applications
Shanghai Zhangjiang Laboratory
2023-2024
Deutsches Elektronen-Synchrotron DESY
2018-2024
Lawrence Berkeley National Laboratory
2016-2019
Tsinghua University
2008-2013
Brookhaven National Laboratory
2009-2011
National Synchrotron Light Source II
2010
Heriot-Watt University
2002
With progress of photoinjector technology, thermal emittance has become the primary limitation electron beam brightness. Extensive efforts have been devoted to study emittance, but experiment results differ between research groups and few can be well interpreted. Besides ambiguity photoemission mechanism, variations cathode surface conditions during preparation, such as work function, field enhancement factor, roughness, will cause differences. In this paper, we report an experimental...
We report the first experimental characterization of efficiency and spectrum enhancement in a laser-seeded free-electron laser using tapered undulator. Output spectra fundamental third harmonic were measured versus distance for uniform undulators. With 4% field taper over 3 m, 300% (50%) increase (third harmonic) output was observed. A significant improvement with elimination sidebands observed The experiment is good agreement predictions MEDUSA simulation code.
Temporally modulated electron beams have a wide array of applications ranging from the generation coherently enhanced electromagnetic radiation to resonant excitation wakefields in advanced-accelerator concepts. Likewise producing low-energy ultrashort microbunches could be useful for ultrafast diffraction and new accelerator-based light-source In this Letter we propose experimentally demonstrate passive microbunching technique capable forming picosecond bunch train at...
Cylindrical asymmetry of an rf gun cavity excites the multipole field which will result in emittance growth electron beams. With demanding beams ultralow for x-ray free laser, it is necessary to study effect and eliminate on beam gun. In this paper, we present both theoretical analysis numerical simulations growth. We proposed a four-hole scheme minimize from field.
Electron photoinjectors provide high-brightness electron beams to numerous research applications in physics, chemistry, material, and life sciences. Semiconductor photocathodes are widely used here, as they enable the production of low-emittance with variable charge at high repetition rates. One key figures merit is minimum achievable bunch length. In semiconductor cathodes, this dominated by scattering effects varying penetration depths extracting photons, which leads a characteristic...
We report the experimental characterization of high-brightness electron beam generation from a magnesium (Mg) photocathode. Both quantum efficiency (QE) and thermal emittance an Mg cathode are experimentally investigated. The measured QE∼0.2% is highest reported for metal cathode. observed no change in as QE varies 0.015% to 0.15%. upper-limit emittance, 0.5 mm mrad, about 50% lower than theoretical prediction. Our results demonstrated feasibility having high low simultaneously robust
The very-high-frequency gun (VHF-Gun) is a new concept photo-injector developed and built at the Lawrence Berkeley National Laboratory (LBNL) for generating high-brightness electron beams capable of driving X-ray free lasers (FELs) MHz-class repetition rates. that purposely uses established mature radiofrequency mechanical technologies has demonstrated over last many years capability reliably operating in continuous wave mode design accelerating fields required vacuum performance. results...
Abstract Development of an accelerator-based tunable THz source prototype for pump-probe experiments at the European XFEL is ongoing Photo Injector Test facility DESY in Zeuthen (PITZ). The proof-of-principle on SASE FEL are performed utilizing LCLS-I undulator (on loan from SLAC) installed PITZ beamline. first lasing a center wavelength 100 μm was observed summer 2022. narrowband achieved using electron beam with energy ∼17 MeV and bunch charge up to several nC. Optimization transport...
The high peak current of the electron beam was found to be key parameter for THz SASE FEL at Photo Injector Test facility DESY in Zeuthen (PITZ). A multipurpose bunch compressor implemented PITZ expand space proof-of-principle studies on tunable high-power accelerator-based source pump-probe experiments European XFEL. magnetic chicane, consisting four rectangular dipole magnets, is designed with a bending angle 19 degrees, due limited original beamline, compress bunches momentum 15–20 MeV/c...
In state of the art photoemission electron sources, transverse emittance beam is approaching its intrinsic value from cathode. To reduce emittance, it straightforward to tune photon energy drive laser toward photocathode emission threshold. This paper aims at constructing an improved model which takes into account intermediate level better explain near threshold for semiconductors. A dynamic also proposed evaluate cathode degradation process due surface oxidation. The models agree well with...
Slice energy spread is one of the key parameters in free electron laser optimizations, but its accurate measurement not straightforward. Two recent studies from high ($>$100 MeV) photoinjectors at SwissFEL and European XFEL have reported much higher slice than expected their working points (200 - 250 pC). In this paper, a new method for measuring lower beam ($\sim$20 proposed demonstrated PhotoInjector Test facility DESY Zeuthen (PITZ), results pC 500 are those measured injectors.
We present the first experimental studies of initial source electron beam microbunching instability in a free laser (FEL) injector. By utilizing for transform-limited pulse at photocathode, we eliminated laser-induced National Synchrotron Light Source Development Laboratory (SDL). The detailed measurements resulting led us to conclude that, SDL, arising from shot noise is not amplified any significant level, thereby allowing set an upper limit on modulation depth noise. Our analysis...
In state of the art photoinjector electron sources, thermal emittance from photoemission dominates final injector emittance. Therefore, low cathode developments and diagnostics are very important. Conventional measurements for high gradient gun time-consuming thus is not measured as frequently quantum efficiency during lifetime photocathodes, although both important properties optimizations. this paper, a single shot measurement transverse momentum, i.e., per rms laser spot size, proposed...
After the successful commissioning of European XFEL in pulsed mode, continuous wave (CW) mode operation X-ray Free-Electron Laser (XFEL) is under considerations for future upgrade. DESY push-ing R&D on CW electron sources. A fully superconducting gun experimental development at Hamburg, and a normal conducting (NC) physics design Photo Injector Test facility Zeuthen (PITZ) as backup option. 217 MHz NC developed from LBNL 187 VHF gun, with enhancement both cathode gradient voltage to further...
Abstract Methodical studies to improve the existing e-beam Longitudinal Phase Space (LPS) tomography were performed at Photo Injector Test facility DESY in Zeuthen. Proof-of-principle simulations done address some core concerns e.g. booster phase range, space charge effects and noisy artefacts results. advance analysis was with help of an analytical model that determined range step size. A slit introduced before truncate beam reduce forces. The reconstruction method adopted image algorithm...
The injector for ERL-FEL has been widely researched. Unlike traditional linacs, the bunch in ERLs requires additional deflection and matching section at lower energies. It makes more susceptible to effects of Space Charge. This will lead a degradation beam quality. In this paper, we comprehensively analyze impact space charge on ERL-injector propose new design concepts further maintain