- 标题
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Fast global orbit feedback system in PLS-II
摘要： The transverse position of the electron beam in the Pohang Light Source-II is stabilized by the global orbit feedback system. A slow orbit feedback system has been operating at 2 Hz, and a fast orbit feedback (FOFB) system at 813 Hz was installed recently. This FOFB system consists of 96 electron-beam-position monitors, 48 horizontal fast correctors, 48 vertical fast correctors and Versa Module Europa bus control system. We present the design and implementation of the FOFB system and its test result. Simulation analysis is presented and future improvements are suggested.
关键词： Instrumentation for particle accelerators and storage rings - high energy (linear accelerators, synchrotrons),Instrumentation for synchrotron radiation accelerators,Accelerator Subsystems and Technologies
更新于2025-09-23 15:22:29
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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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[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 23rd International Conference on Mechatronics Technology (ICMT) - SALERNO, Italy (2019.10.23-2019.10.26)] 2019 23rd International Conference on Mechatronics Technology (ICMT) - Toward the Application of Reinforcement Learning to the Intensity Control of a Seeded Free-Electron Laser
摘要： The optimization of particle accelerators is a challenging task, and many different approaches have been proposed in years, to obtain an optimal tuning of the plant and to keep it optimally tuned despite drifts or disturbances. Indeed, the classical model-free approaches (such as Gradient Ascent or Extremum Seeking algorithms) have intrinsic limitations. To overcome those limitations, Machine Learning techniques, in particular, the Reinforcement Learning, are attracting more and more attention in the particle accelerator community. The purpose of this paper is to apply a Reinforcement Learning model-free approach to the alignment of a seed laser, based on a rather general target function depending on the laser trajectory. The study focuses on the alignment of the lasers at FERMI, the free-electron laser facility at Elettra Sincrotrone Trieste. In particular, we employ Q-learning with linear function approximation and report experimental results obtained in two setups, which are the actual setups where the final application has to be deployed. Despite the simplicity of the approach, we report satisfactory preliminary results, that represent the first step toward a fully automatic procedure for seed laser to the electron beam. Such a superimposition is, at present, performed manually.
关键词： Free-Electron Laser,Particle Accelerators,Q-learning,Reinforcement Learning,Machine Learning
更新于2025-09-19 17:13:59
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Laser Engineered Surface Structures for Custom Design of Secondary Electron Yield
摘要： Secondary Electron Yield (SEY) occurs in a system when a primary electron impinges a material’s surface and induces the emission of a 1st and potentially 2nd generation secondary electrons. The total number of secondary electrons per primary electron is the SEY. This phenomenon forms a highly challenging problem in many systems, for example in particle accelerators, where significant levels of SEY form as an electron cloud and can perturbate the circulating beams and generate a high level of heat load to be absorbed by cooling and cryogenics. The Large Hadron Collider (LHC) has a 54-km beam pipe in which copper-laminated steel beam-screens are placed in order to shield the beam pipes from heat loads, but inherently result in unwanted SEY. As such, the development of methods which mitigate the SEY are increasingly appealing, including surface texturing, shaping the geometry and orientation of patterns etched into the surfaces, and carbon-coating of the interior of the beam pipes in the Super Proton Synchrotron (SPS). Previously we have shown that nanosecond pulsed laser treatment of copper surfaces at 532 nm could significantly increase the optical absorbance of the surface, and furthermore reduce the SEY to close to 1. More recently we demonstrated that surface structures produced by a picosecond pulsed laser at 532nm exhibited SEY values below 1 and were successfully tested in a dipole magnet in the Super Proton Synchrotron (SPS) accelerator at CERN.
关键词： laser treatment,Secondary Electron Yield,copper surfaces,SEY,particle accelerators
更新于2025-09-11 14:15:04