- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Wavelet Analysis and Decomposition Into Color Spaces in Researching of Human Fluorescently Labeled Images Tissues
摘要： At the Linac Coherent Light Source (LCLS) X-ray free-electron laser, a laser “heater” is used to generate an uncorrelated 20-keV energy spread on an electron beam to suppress the microbunching instability in downstream bunch compressors. Here we describe an alternative approach using emittance partitioning, where the increase in energy spread is generated by moving phase space volume from the transverse dimensions into the longitudinal dimension. For LCLS-relevant beam parameters, about a factor of six reduction in the product of both transverse emittances is feasible with the same amount of induced energy spread, with additional improvements possible with an optimized setup.
关键词： particle accelerators,electron beams,free-electron lasers,Electron accelerators
更新于2025-09-23 15:21:01
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Tilted Snowplow Ponderomotive Electron Acceleration With Spatio-Temporally Shaped Ultrafast Laser Pulses
摘要： We propose a novel scheme for using the ponderomotive force of a tilted ultrafast laser pulse to accelerate electrons in free space. The tilt of the intensity envelope results from the angular dispersion of the pulse’s spectrum and slows down the interaction of the pulse with free electrons. The slower effective pulse velocity allows time for the electrons to accelerate from rest while remaining on the wave. We present both non-relativistic and relativistic analytic single-particle models in the adiabatic ponderomotive approximation, describing the process for an ideal infinite tilted pulse as well as a finite width beam. The analysis predicts the threshold intensity as a function of the pulse front tilt angle and shows that in the ideal case the output energy of the electrons is four times that of the ponderomotive potential at the capture threshold. Full-field simulations using the 2D OSIRIS 4.0 particle-in-cell code confirm the basic scheme. This tilted pulse acceleration scheme shows promise as a lab-scale method of accelerating electrons to the MeV level with good energy and angular resolution, to be used for ultrafast electron diffraction or injection into a second stage accelerator.
关键词： ponderomotive force,spatio-temporal pulse shaping,ultrafast lasers,laser electron accelerators,relativistic kinematics
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - High-Frequency Modulated Photoluminescence: a simulation study of cases describing the signature of carrier recombination and trap centers
摘要： At the Linac Coherent Light Source (LCLS) X-ray free-electron laser, a laser “heater” is used to generate an uncorrelated 20-keV energy spread on an electron beam to suppress the microbunching instability in downstream bunch compressors. Here we describe an alternative approach using emittance partitioning, where the increase in energy spread is generated by moving phase space volume from the transverse dimensions into the longitudinal dimension. For LCLS-relevant beam parameters, about a factor of six reduction in the product of both transverse emittances is feasible with the same amount of induced energy spread, with additional improvements possible with an optimized setup.
关键词： particle accelerators,electron beams,free-electron lasers,Electron accelerators
更新于2025-09-19 17:13:59
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Compact low-pass/band-pass filters based on quarter-mode substrate integrated waveguide and a connected network of CSRRs
摘要： At the Linac Coherent Light Source (LCLS) X-ray free-electron laser, a laser “heater” is used to generate an uncorrelated 20-keV energy spread on an electron beam to suppress the microbunching instability in downstream bunch compressors. Here we describe an alternative approach using emittance partitioning, where the increase in energy spread is generated by moving phase space volume from the transverse dimensions into the longitudinal dimension. For LCLS-relevant beam parameters, about a factor of six reduction in the product of both transverse emittances is feasible with the same amount of induced energy spread, with additional improvements possible with an optimized setup.
关键词： free-electron lasers,electron beams,particle accelerators,Electron accelerators
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Intra-hour Cloud Index Forecasting with Data Assimilation
摘要： At the Linac Coherent Light Source (LCLS) X-ray free-electron laser, a laser “heater” is used to generate an uncorrelated 20-keV energy spread on an electron beam to suppress the microbunching instability in downstream bunch compressors. Here we describe an alternative approach using emittance partitioning, where the increase in energy spread is generated by moving phase space volume from the transverse dimensions into the longitudinal dimension. For LCLS-relevant beam parameters, about a factor of six reduction in the product of both transverse emittances is feasible with the same amount of induced energy spread, with additional improvements possible with an optimized setup.
关键词： free-electron lasers,electron beams,particle accelerators,Electron accelerators
更新于2025-09-19 17:13:59
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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - Topological edge state laser using a photonic crystal nanocavity array
摘要： In next-generation light sources, high-brightness electron beams are used in a free-electron laser configuration to produce light for use by scientists and engineers in numerous fields of research. High-brightness beams are described for such light sources as having low transverse and longitudinal emittances, high peak currents, and low slice emittance and energy spread. The optimal generation and preservation of such high-brightness electron beams during the acceleration process and propagation to and through the photon-producing element is imperative to the quality and performance of the light source. To understand the electron beam’s phase space in the accelerating section of a next-generation light source machine, we employed radio-frequency cavities operating in a deflecting mode in conjunction with a magnetic spectrometer and imaging system for both low (250 MeV) and high (1.2 GeV) electron energies. This high-resolution, high-energy system is an essential diagnostic for the optimization and control of the electron beam in the FERMI light source generating fully transversely and longitudinally coherent light in the VUV to soft x-ray wavelength regimes. This device is located at the end of the linear accelerator in order to provide the longitudinal phase space nearest to the entrance of the photon-producing beam-lines. Here, we describe the design, fabrication, characterization, commissioning, and operational implementation of this transverse deflecting cavity structure diagnostic system for the high-energy (1.2 GeV) regime.
关键词： electron beam deflection,free-electron lasers,particle beam measurements,Electron accelerators
更新于2025-09-19 17:13:59
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Circumventing the Dephasing and Depletion Limits of Laser-Wakefield Acceleration
摘要： Compact electron accelerators are paramount to next-generation synchrotron light sources and free-electron lasers, as well as for advanced accelerators at the TeV energy frontier. Recent progress in laser-plasma driven accelerators (LPA) has extended their electron energies to the multi-GeV range and improved beam stability for insertion devices. However, the subluminal group velocity of plasma waves limits the final electron energy that can be achieved in a single LPA accelerator stage, also known as the dephasing limit. Here, we present the first laser-plasma driven electron accelerator concept providing constant acceleration without electrons outrunning the wakefield. The laser driver is provided by an overlap region of two obliquely incident, ultrashort laser pulses with tilted pulse fronts in the line foci of two cylindrical mirrors, aligned to coincide with the trajectory of the accelerated electrons. Such a geometry of laterally coupling the laser into a plasma allows for the overlap region to move with the vacuum speed of light, while the laser fields in the plasma are continuously being replenished by the successive parts of the laser pulses. Our scheme is robust against parasitic self-injection and self-phase modulation as well as drive-laser depletion and defocusing along the accelerated electron beam. It works for a broad range of plasma densities in gas targets. This method opens the way for scaling up electron energies beyond 10 GeV, possibly towards TeV-scale electron beams, without the need for multiple laser-accelerator stages.
关键词： Laser-wakefield acceleration,photonics,optics,electron accelerators,plasma physics
更新于2025-09-11 14:15:04