Paper | Title | Other Keywords | Page |
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MOPMB014 | Simultaneous Detection of Longitudinal and Transverse Bunch Signals at ANKA | synchrotron, detector, radiation, synchrotron-radiation | 109 |
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Funding: This work has been supported by the Initiative and Networking Fund of the Helmholtz Association under contract number VH-NG-320 and by the BMBF under contract number 05K13VKA. The ANKA storage ring offers different operation modes including the short-bunch mode with bunch lengths tuned down to a few picoseconds. This can lead to the occurrence of micro-bunching instabilities coupled to the emission of coherent synchrotron radiation (CSR) in so-called 'bursts'. To study this CSR instability we use several turn-by-turn enabled detector systems to synchronously measure both the THz signal as well as bunch profiles. The different detectors are placed at different locations around the storage ring. Here we discuss the experimental setup and calibration of the various systems' synchronisation. |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB014 | ||
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MOPOW028 | Research on Pulse Energy Fluctuation of a Cascaded High Gain Harmonic Generation Free Electron Laser | electron, FEL, laser, linac | 781 |
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Shot to shot pulse energy fluctuation is one of the most critical issues for two-stage cascaded high gain harmonic generation (HGHG) free electron lasers (FELs). In this paper, we study the effects of various electron parameters jitters on the output pulse energy fluctuations based on Shanghai Soft X-ray free electron laser facility (SXFEL). The results show that the relative timing jitter between the electron beam and the seed laser is proved to be the most sensitive factor. The energy jitter and charge jitter make some contributions and are non-ignorable as well. Some comparisons between our facility and FERMI have been made and we hope the conclusions draw from this study would be a reference for the optimization of future seeded FEL facilities based on cascading stages of HGHG. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW028 | ||
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TUPOW027 | Model Independent Analysis of Beam Jitter on VELA | laser, cathode, distributed, gun | 1806 |
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The Versatile Electron Linear Accelerator (VELA) is a facility designed to provide high quality electron beams for accelerator systems development, as well as industrial and scientific applications. A key performance indicator for many applications is the inherent beam jitter on the machine (temporal, momentum and positional). Analysis of this beam jitter indicates that there are several independent mechanisms driving the beam motion. We use model independent analysis to correlate various dominant modes of beam jitter and compare them to simulations. We also compare the dominant modes before and after intervention work on the DLLRF timing system, and determine the relevant changes in beam motion. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW027 | ||
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WEPOR004 | Fast Orbit Feedback System at the Pls-Ii Storage Ring | feedback, electron, storage-ring, operation | 2667 |
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Funding: This work is supported by the Ministry of science, ICT and Future Planning, Korea. The transverse position of the electron beam in the Pohang Light Source-II (PLS-II) is stabilized by the global orbit feedback system. Currently, 2 Hz slow orbit feedback (SOFB) system is operating, and 1 kHz fast orbit feedback (FOFB) system is installed recently. This FOFB system is consists of 96 electron beam position monitors (BPMs), 48 horizontal fast correctors, 48 vertical fast correctors and VME control system. We present the design and implementation of the FOFB system and its test result. Analysis through the simulation is presented and future improvement is discussed |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR004 | ||
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WEPOR010 | Recent Upgrades to the CERN SPS Wideband Intra-bunch Transverse Feedback Processor | feedback, controls, FPGA, operation | 2687 |
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In support of the CERN High Luminosity LHC (HL-LHC) upgrade program, a research and development effort has been underway to understand and develop feedback control techniques for mitigating transverse intra-bunch instabilities in the SPS driven by electron cloud and TMCI effects. These effects could be a limiting factor to overall machine performance. A result of this effort has been the development of a very wide band transverse feedback demonstration system. This system has been used for the last several years in machine development studies where we have demonstrated single-bunch stability control of low order intra-bunch modes. In continuation of these efforts, recent upgrades have been performed in all stages of the system, including the feedback processor itself. This paper discusses the upgrades specific to it, including the ability to process multiple proton bunches in the SPS; and also highlights future directions in the development effort. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR010 | ||
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WEPOW011 | BESSY II Supports an Extensive Suite of Timing Experiments | experiment, synchrotron, operation, photon | 2840 |
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The synchrotron light source facility BESSY II has put top-up and a fast orbit feedback (FOFB) into operation in 2013. Both operational improvements have matured and turned out to be especially beneficial for the advanced timing opportunities supported at BESSY. In combination with very tight injection efficiency requirements a thorough understanding of top-up injections under all operational conditions has been developed. Consequently arbitrary bunch currents can be dialed in and maintained on demand. In standard mode, a very pure camshaft bunch is available both in general for laser pump/X-ray probe and for pseudo single bunch experiments at the MHz chopper beamline. 3 constant high current bunches support the FEMTOSPEX slicing facility. An additional bunch can be resonantly excited and pulse picked via custom orbit bumps at 3 different undulator beamlines (PPRE). Due to the FOFB the classical timing modes "single bunch" and "low alpha" feature an attractive pointing stability. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW011 | ||
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WEPOW058 | Top-off Tests and Controls Optimization | injection, operation, controls, booster | 2982 |
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Funding: DOE No.DE-AC02- 98CH10886 The National Synchrotron Light Source II (NSLS-II) is a state of the art 3 GeV third generation light source at Brookhaven National Laboratory. As in many other light sources, top-off injection is considered as a standard operation mode resulting in more stable beam intensity to minimize heat load variation on the beamline optics. Top off injection specifications include maintaining the stored beam current within 0.5% and the bunch to bunch charge variation within 20% bands. To make the top off commissioning smooth and efficient, a virtual machine model based on the measured beam properties was developed. The model helped to study robustness of this application operating under different conditions and optimize the input parameters. Once tested the model was transitioned to beam commissioning. To make the beam tests more efficient, the beam lifetime was controlled by adjusting RF voltage and scrapers. In this paper, we'll share the experience from the test stage to machine implementation of the top-off controls. |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW058 | ||
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WEPOY044 | Review of CPU and GPU Faddeeva Implementations | GPU, interface, simulation, space-charge | 3090 |
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Funding: CERN, Doctoral Studentship EPFL, Doctorate The Faddeeva error function is frequently used when computing electric fields generated by two-dimensional Gaussian charge distributions. Numeric evaluation of the Faddeeva function is particularly challenging since there is no single expansion that converges rapidly over the whole complex domain. Various algorithms exist, even in the recent literature there have been new proposals. The many different implementations in computer codes offer different trade-offs between speed and accuracy. We present an extensive benchmark of selected algorithms and implementations for accuracy, speed and memory footprint, both for CPU and GPU architectures. |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY044 | ||
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THOBA03 | Start-to-end Calculations and Trajectory Correction for BERLinPro | laser, linac, simulation, space-charge | 3167 |
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Funding: Work funded by the Bundesministerium für Bildung und Forschung, Land Berlin and grants of the Helmholtz Association BERLinPro is an ERL project under construction at the Helmholtz-Zentrum Berlin, with the goal to illuminate the challenges and promises of a high brightness 100 mA superconducting RF gun in combination with a 50 MeV return loop and energy recovery. Latest changes to the optics code OPAL allow for the first time to perform start-to-end tracking studies including space charge in a single run, without switching between codes. This opens the way to apply correction schemes to displaced trajectories in the complete machine and to study the effect of jitter sources, including the space charge dominated injector, on the machine performance parameters. Trajectory correction is discussed. Jitter is studied with respect to its potential impact on the recovery process and parameter changes before the dump. |
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Slides THOBA03 [5.903 MB] | ||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THOBA03 | ||
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THPMR020 | Bunch Purity Measurements at PETRA III | electron, scattering, synchrotron, operation | 3434 |
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Since 2010 the 6 GeV synchrotron light source PETRA III is in operation. With a horizontal emittance of 1.2 nm*rad, a coupling of typically 1% and a total beam current of 100 mA the machine provides extremely brilliant synchrotron radiation for the users. For time-resolved measurements a filling pattern with 40 equidistant bunches with equal charge is used. To measure parasitic bunches between the main bunches two beamlines are equipped with avalanche photodiodes (APD) and time to digital converters (TDC) electronics. Besides parasitic bunches originating from the pre-accelerators of PETRA III it has been observed that initially empty buckets following the main bunch are populated. Measurements of the effect will be discussed and compared with simulations. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR020 | ||
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THPMW008 | Study of Digital Quench Detection System Based on System-on-Chip Technology | embedded, controls, FPGA, software | 3549 |
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Quench detection system is a key component of the quench protection system for superconducting magnets. According to operating experience of the quench protec-tion system for BEPCII interaction region superconduct-ing magnets and study in depth on the development process of System-on-Chip, we are establishing a set of digital quench detection system with high integration density and favourable portability by integrating IP cores, custom modules and developing embedded soft-ware on one piece of FPGA chip (Cyclone V SX SoC). The main components of this system are: 1.Hard proces-sor system based-on ARM Cortex-A9 architecture inte-grated with embedded operating system (Linux).2.Floating point DSP based-on soft IP core.3.Function Module Portion designed for different functions such as communicating with front end ADC, timing control, etc. This paper introduces the research progress of the system.
*D.F.Orris, S.Feher, M.J.Lamm, J.Nogiec, S.Sharonov, M.Tartaglia, J.Tompkins, et al.," A digital quench detection system for superconducting magnets", Proceedings of PAC'99, New York, 1999. |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW008 | ||
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THPMW021 | Performance of a Compensation Kicker Magnet for J-PARC Main Ring | injection, kicker, pick-up, proton | 3588 |
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Four lumped-type kicker magnets have been equipped in the J-PARC MR (Main Ring) to inject 8 proton bunches. To increase beam power, the bunch length will be increased up to 350 ns that will restricts the rise time of the injection kicker to be less than 250 ns. We have already developed a method to improve the rising time to 200 ns*. However, two reflection pulses are appeared at the waveform tail, which will kick the circulating bunches and induce coherent oscillation leading to beam loss. To compensate reflection pulses, we decide to install two new lumped-type kicker magnets, which are excited independently making operation flexible. A ceramic vacuum duct with TiN coating is inserted in the compensation kickers. Magnetic field measurement and coupling impedance measurement have been carried. In this paper, the results of both these measurements and performance study using proton beam will be discussed.
* T.Sugimot et.al, "Upgrade of the Injection Kicker System for J-PARC Main Ring", MOPME069, IPAC14, Dresden, Germany, 2014. |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW021 | ||
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THPOR041 | High Gradient Properties of a CLIC Prototype Accelerating Structure made by Tsinghua University | operation, accelerating-gradient, vacuum, experiment | 3874 |
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A CLIC prototype structure, T24_THU_#1, was recently high-gradient tested at KEK X-band test stand, Nextef. The copper parts of this 24-cell TW structure were delivered from CERN, were bonded and brazed, bench-tested and tuned in Tsinghua University. The aim of this test was not only to verify the cavity high-gradient properties under 100 MV/m but also to study the breakdown phenomenon in high gradient. High power test results were presented and breakdown rate under 100 MV/m was compared to previously-tested CLIC prototype structures. The assembly capability of Tsinghua University for X-band high gradient structures was validated by the good high gradient performance of T24_THU_#1. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR041 | ||
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THPOW027 | Compact X-band Accelerator Controls for a Laser-Compton X-ray Source | controls, laser, LabView, interface | 3996 |
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Funding: This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL's compact, tunable, laser-Compton x-ray source has been built around an advanced X-band photogun and accelerator sections and two independent laser systems. In support of this source, a complete integrated control system has been designed and built from scratch to provide access to the critical control points and continues to grow to simplify operation of the system and to meet new needs of this research capability. In addition to a PLC-based machine protection component, a custom, LabView-based suite of control software monitors systems including low level and high power RF, vacuum, magnets, and beam imaging cameras. This system includes a comprehensive operator interface, automated and expandable arc detection to optimize rf conditioning of the high-gradient structures, and automated quad-scan-based emittance measurements to explore the beam tuning parameter space. An overview of this system is presented, including the latest upgrades to FPGA-based hardware for the RF system controls. |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW027 | ||
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THPOY003 | The Turn-key Control System for the ELI-NP Gamma Beam System | controls, EPICS, laser, electron | 4091 |
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The new Gamma Beam System (GBS) under construction in Magurele (RO) by the consortium EuroGammas led by INFN, as part of the ELI-NP project, can provide gamma rays that open new possibilities for nuclear photonics and nuclear physics. In the ELI-GBS, gamma rays are produced by means of Compton back-scattering to get mono-chromaticity (0,1% bandwidth), a high flux (1013 photon/s the highest in the world), tunable directions and energies up to 19 MeV. Such gamma beam characteristic is obtained when a high-intensity laser collides a high-brightness electron-beam with energies up to 720 MeV. In order to increase the gamma beam flux, the electron beam operates at a repetition rate of 100 Hz in a multi-bunch mode: trains of 32 bunches, 16 ns apart, interact with the laser pulse recirculated 32 times through the interaction point. The EPICS Control System collects data from all sub-systems, constantly monitoring to ensure the safety of the ELI-GBS facility. This paper describes all the aspects of the ELI-GBS turn-key Control System, such as hardware integration, micro-bunches diagnostics, high level applications, the data network and the pico-second timing system. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY003 | ||
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THPOY008 | Tango Based Control System at SOLARIS Synchrotron | controls, TANGO, PLC, device-server | 4101 |
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A National Synchrotron Radiation Centre SOLARIS has been recently built in Kraków, Poland. The accelerator is in commissioning phase. The control system is in operation and provides all functionalities required for the commissioning process. The system is based on Tango Controls and has been developed with strong collaboration with MAX-IV, Lund Sweden and the Tango Community. Protections systems uses Rockwell and Siemens PLC hardware. Synchronization system is based on the MRF hardware. Status, technologies and performance experience will be presented. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY008 | ||
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THPOY016 | Fast Machine Interlock Platform for Reliable Machine Protection Systems | hardware, power-supply, EPICS, controls | 4119 |
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This article presents a machine interlock system (MIS), designed and developed in collaboration between SINAP and Cosylab. The design is based on the experience and requirements of different accelerator facilities around the world, with the goal of providing, out of the box, the flexibility, reliability, availability, determinism, response speed, etc., which facilities need for a Machine Protection System (MPS). The goal of the MIS platform is to provide a reliable tool, which covers all the common MIS behaviour, required by an MPS designer. The system is based on a proven hardware platform, uses radiation-tolerant FPGAs, has built-in redundancies for power supply, hardware components and logic and is configurable from EPICS. We present several design principles that were used and explain the features and principles of application. Furthermore, we present the system architecture, from hardware and firmware to software. The MIS system is currently being installed at the BNCT facility at the Ibaraki Neutron Medical Research Center in Japan and is planned in the treatment interlock system of APTRON, the Advanced Proton Therapy Facility in Shanghai, China. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY016 | ||
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THPOY019 | Design and Implementation of Control Interface and Timing Support of TPS Phase-I Beamlines | EPICS, controls, injection, status | 4128 |
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Taiwan Photon Source (TPS) with low emittance provides extremely bright X-rays. Seven advanced phase-I beamlines of TPS are being constructed and commissioned. The control interfaces for a beamline or experimental station and support from the accelerator control system are designed and are being implemented. The beamline control interface and supports include a beamline interlock status monitor, accelerator timing transmission, broadcast of accelerator operating status, transmission of the beam-current reading and control of insertion devices. This report summarizes the efforts in implementing the beamline EPICS IOC and support from the accelerator control system during beamline commissioning in TPS phase-I. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY019 | ||
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THPOY048 | NSLS-II Active Interlock System and Post-Mortem Architecture | status, operation, FPGA, hardware | 4214 |
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The NSLS-II at Brookhaven National Laboratory (BNL) started the user beam service in early 2015, and is currently operating 13 of the insertion device (ID) and beamlines as well as constructing new beamlines. The fast machine protection consists of an active interlock system (AIS), beam position monitor (BPM), cell controller (CCs) and front-end (FE) systems. The AIS measures the electron beam envelop and the dumps the beam by turning off RF system, and then the diagnostic system provides the post-mortem data for an analysis of which system caused the beam dump and the machine status analysis. NSLS-II post-mortem system involves AIS, CCs, BPMs, radio frequency system (RFs), power supply systems (PSs) as well as the timing system. This paper describes the AIS architecture and PM performance for NSLS-II safe operations. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY048 | ||
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THPOY051 | Upgrades to the SPEAR3 Single-Photon Bunch Measurement System | controls, EPICS, software, interface | 4223 |
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The SPEAR3 accelerator uses a Single Photon Time-Correlated Counting (TCSPC) system to accurately measure the time profile of electron bunches circulating in the storage ring. The detection hardware uses the PicoHarp 300 TCSPC processor module initially equipped with an available Hamamatsu H7360-01 photon counting head. The H7360-01 was later replaced with a PicoQuant Hybrid-06 PMA to decrease single-photon arrival time jitter. At the same time we adopted an EPICS-based TCSPC software package developed at DIAMOND for robust data acquisition and display. In this paper we report on recent beam profile measurements and upgrades to the data acquisition software system including installation of a local EPICS IOC for real-time access to the bunch profile from SLAC's centralized Accelerator Control Room (ACR). High-level operator interface and monitoring applications developed in Python are discussed. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY051 | ||
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THPOY054 | An External Synchronization of PHIL to a High Power Femtosecond Laser | electron, laser, gun, cavity | 4228 |
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The synchronization accuracy between laser systems and RF wave is a crucial ingredient for the successful operation of any particle accelerator based on photo-emission. In the case of ultra-short highly charged electron accelerator, the beam is highly sensitive to timing jitter. Thus, a high level of synchronization accuracy is needed. In this paper, we describe the current synchronization system of PHIL (electron accelerator at LAL), and a new approach to synchronize PHIL externally with a high power femtosecond laser (LASERIX) . The main goal of the experience is to design and study a compact way to obtain ultra-short electron bunches (few tens to few hundreds of femtoseconds) under high charge levels (hundred pC). We continue with a description of different modifications made on PHIL timing master to adapt it to external synchronization. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY054 | ||
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THPOY056 | Implementation of SINAP Timing System in Shanghai Proton Therapy Project | proton, hardware, extraction, synchrotron | 4231 |
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Funding: The project of SINAP Timing System was supported by the National Natural Science Foundation of China (No. 11305246). SINAP v2 timing system was implemented in the timing system of Shanghai Proton Therapy Project. The timing system in Shanghai Proton Therapy Project is required not only to generate operation sequence for medical proton synchrotron, but also to realize irradiation flow for beam delivery system. For these purposes, the firmware of SINAP v2 timing system is redesigned to satisfy both event code sequenced broadcasting to generate operation sequence and bidirectional event code transmit to realize irradiation flow. Thanks of the hardware advantage of SINAP v2 timing system, the event receiver (EVR) could transmit event code to event generator (EVG) and then broadcast to timing network by bidirectional transmit ability. By this design, the EVR installed in treatment room has ability to send event code to timing network to stop/start beam during slow extraction. The architecture of the timing system in Shanghai Proton Therapy Project is presented in the paper. The risk analysis is also described in detail. |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY056 | ||
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THPOY057 | RF Timing Distribution and Laser Synchronization Commissioning of PAL-XFEL | laser, linac, LLRF, FEL | 4234 |
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PAL-XFEL requires <100 fs synchronization of LLRF systems and optical lasers for stable operation and even lower jitter is favorable in higher performance and pump-probe experiments. The RF timing distribution system is based on a 476 MHz reference line, which is converted to 2.856 GHz at 16 locations over 1.5 km distance using phase-locked DRO. The 2.856 GHz signals are amplified and split to 10 outputs, which is connected to LLRFs, BAMs, and DCMs through low timing drift cables. The jitter between two different PLDRO units is estimated to ~1 fs from 1 Hz to 1 MHz. The synchronization jitter between a Ti:sapphire laser and the 2.856 GHz signal is measured less than 20 fs. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY057 | ||
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THPOY060 | Four Beam Generation for Simultaneous Four-Hall Operation at CEBAF | laser, electron, space-charge, gun | 4240 |
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Funding: Authored by JSA, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Gov't retains a non-exclusive, paidup, irrevocable, worldwide license to publish or reproduce this for U.S. Gov't purposes. As part of the CEBAF 12 GeV upgrade at Jefferson Lab, a new experimental hall was added to the existing three halls. To deliver beam to all four halls simultaneous-ly, a new timing pattern for electron bunches is needed at the injector. This pattern change has consequences for the frequency of the lasers at the photogun, beam behavior in the chopping system, beam optics due to space charge, and setup procedures. We have successfully demonstrated this new pattern using the three existing drive lasers. The implementation of the full system will occur when the fourth laser is added and upgrades to the Low Level RF (LLRF) are complete. In this paper we explain the new bunch pattern, the challenges for setting and measuring the pattern such as 180° RF phase ambiguity, addition of the fourth laser to the laser table and LLRF upgrade. |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY060 | ||
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