Keyword: laser
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MOBO01 Overview of the Beam Instrumentation and Commissioning Results from the BNL Low Energy RHIC Electron Cooling Facility electron, gun, cathode, MMI 14
 
  • T.A. Miller, Z. Altinbas, D. Bruno, J.C. Brutus, M.R. Costanzo, L. DeSanto, C. Degen, K.A. Drees, A.V. Fedotov, W. Fischer, J.M. Fite, D.M. Gassner, X. Gu, J. Hock, R.L. Hulsart, P. Inacker, J.P. Jamilkowski, D. Kayran, J. Kewisch, C. Liu, K. Mernick, R.J. Michnoff, M.G. Minty, S.K. Nayak, L.K. Nguyen, P. Oddo, R.H. Olsen, M.C. Paniccia, W.E. Pekrul, I. Pinayev, V. Ptitsyn, V. Schoefer, S. Seletskiy, H. Song, A. Sukhanov, P. Thieberger, J.E. Tuozzolo, D. Weiss
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Con-tract No. DE-AC02-98CH10886 with the U.S. Department of Energy
The Low Energy RHIC Electron Cooling (LEReC) facility at BNL demonstrated, for the first time, cooling of ion beams using a bunched electron beam from an SRF accelerating cavity and photoinjector. LEReC is planned to be operational to improve the luminosity of the Beam Energy Scan II physics program in RHIC in the following two years. In order to establish cooling of the RHIC Au ion beam using a 20 mA, 1.6 MeV bunched electron beam; absolute energy, angular and energy spread, trajectory and beam size were precisely matched. A suite of instrumentation was commissioned that includes a variety of current transformers, capacitive pick-up for gun high voltage ripple monitor, BPMs, transverse and longitudinal profile monitors, multi-slit and single-slit scanning emittance stations, time-of-flight and magnetic field related energy measurements, beam halo & loss monitors and recombination monitors. The commissioning results and performance of these systems are described, including the latest design efforts of high-power electron beam transverse profile monitoring using a fast wire scanner, residual gas beam induced fluorescence monitor, and Boron Nitride NanoTube (BNNT) screen monitor
 
slides icon Slides MOBO01 [17.119 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOBO01  
About • paper received ※ 05 September 2019       paper accepted ※ 11 September 2019       issue date ※ 10 November 2019  
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MOPP034 Beam Instrumentation Challenges for the Fermilab PIP-II Accelerator linac, MEBT, emittance, instrumentation 180
 
  • V.E. Scarpine, N. Eddy, D. Frolov, M.A. Ibrahim, L.R. Prost, R.M. Thurman-Keup
    Fermilab, Batavia, Illinois, USA
 
  Funding: This work was supported by the U.S. Department of Energy under contract No. DE-AC02-07CH11359.
Fermilab is undertaking the development of a new 800 MeV superconducting RF linac to replace it’s present normal conducting 400 MeV linac. The PIP-II linac warm front-end consists of an ion source, LEBT, RFQ and MEBT which includes an arbitrary pattern bunch chopper, to generate a 2.1 MeV, 2mA H beam. This is followed immediately by a series of superconducting RF cryomodules to produce a 800 MeV beam. Commissioning, operate and safety present challenges to the beam instrumentation. This paper describes these beam instrumentation challenges and the choices made for PIP-II.
 
poster icon Poster MOPP034 [0.999 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP034  
About • paper received ※ 10 September 2019       paper accepted ※ 11 September 2019       issue date ※ 10 November 2019  
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MOPP048 Development of the Linac Extension Area 450-MeV Electron Test Beam Line at the Advanced Photon Source* electron, linac, experiment, gun 220
 
  • W. Berg, J.C. Dooling, S.H. Lee, Y. Sun, A. Zholents
    ANL, Lemont, Illinois, USA
 
  Funding: *Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-ACO2O6CH11357.
A low-emittance electron beam line for accelerator-based R&D hardware experimentation and study of novel accelerator techniques is under development at the injection linac of the Advanced Photon Source (APS). The Linac Extension Area (LEA) beam line will operate at the full 400 MeV energy of the APS linac. The electron beam is generated from a photo-cathode (PC) electron gun delivering 300 pC of charge with a 3 ps, rms bunch length and normalized beam emittance of ~ 1 micron. The bunch length can be compressed to 150 fs in a flexible chicane at a beam energy of 150 MeV. The APS linac contains an extensive set of conventional and advanced beam diagnostics including a recently commissioned s-band transverse deflecting cavity. The low-emittance electron beam is transported to an independent experimental tunnel enclosure that contains the LEA beam line. Implementing the LEA beam line separate from the APS injector complex allows for on-demand access to the area to perform work without interrupting beam operations of the APS. We discuss the overall scheme of the existing linac beam delivery & diagnostic systems, and report the design of the LEA beam line and initial planned experiments.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP048  
About • paper received ※ 05 September 2019       paper accepted ※ 09 September 2019       issue date ※ 10 November 2019  
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TUPP001 KALYPSO: Linear Array Detector with Continuous Read-Out at MHz Frame Rates FEL, detector, electron, radiation 266
 
  • C. Gerth, B. Steffen
    DESY, Hamburg, Germany
  • M. Caselle, L. Rota
    KIT, Karlsruhe, Germany
  • D.R. Makowski, A. Mielczarek
    TUL-DMCS, Łódź, Poland
 
  The novel linear array detector KALYPSO has been developed for beam diagnostics based on 1-dimensional profile measurements at high-repetition rate free-electron lasers (FEL) and synchrotron radiation facilities. The current version of KALYPSO has 256 pixels with a maximum frame rate of 2.7~MHz. The detector board, which comprises the radiation sensor, analog signal amplification, and analog-to-digital signal conversion, has been designed as a mezzanine card that can be plugged onto application-specific carrier boards for data pre-processing and transmission. Either a Si or InGaAs sensor can be mounted for the detection of visible or near infrared radiation. Results obtained in several beam diagnostics applications at the European XFEL and FLASH are presented to demonstrate the powerful capabilities of the KALYPSO detector.
* The KAYLYPSO detector is a collaboration between the Karlsruhe Institute of Technology, Paul Scherrer Institut, Łódź University of Technology, and Deutsches-Elektronen Synchrotron.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP001  
About • paper received ※ 04 September 2019       paper accepted ※ 07 September 2019       issue date ※ 10 November 2019  
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TUPP002 Direct-Sampling Coarse Bunch Arrival Time Monitor in the Free Electron Laser FLASH Based on the Fast Digitizer Implemented in the FMC VITA 57.1 Standard FEL, pick-up, electron, timing 270
 
  • J. Zink, M.K. Czwalinna, M. Fenner, S. Jabłoński, J. Marjanovic, H. Schlarb
    DESY, Hamburg, Germany
  • F. Gerfers
    Technische Universität Berlin, Berlin, Germany
 
  At the free-electron lasers FLASH and European-XFEL bunch arrival times are monitored with a high-accuracy electro-optical based data acquisition system (BAM). Due to only a couple of picoseconds time measurement range of this system, large timing changes might cause the monitor to fail. To remove any ambiguity and for health status monitoring a high-speed direct-sampling FPGA mezzanine card (FMC) and an analogue RF front-end was added. The circuitry has lower precision than the electro-optical based BAM, but it can determine bunch arrival time with respect to a reference signal over a large time range, i.e. of the order of 1 ms. After restarts or larger energy changes during operation, the electron bunch arrival time may have been changed by tens or even hundreds of picoseconds, which causes that the BAM is out of its operation range and needs to be recalibrated. With the solution developed, the BAM gets the coarse bunch timing from the digitizer and adjusts its optical delay lines accordingly. This allows for finding the operation point fast and automatically. Performance data of the fast direct-sampling digitizer FMC and first measurement data from FLASH will be presented.  
poster icon Poster TUPP002 [3.810 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP002  
About • paper received ※ 04 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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TUPP012 Image of the Transverse Bunch Profile via COTR electron, radiation, target, detector 308
 
  • A. Potylitsyn, T. Gusvitskii, L.G. Sukhikh
    TPU, Tomsk, Russia
  • G. Kube, A.I. Novokshonov
    DESY, Hamburg, Germany
 
  Funding: This work was supported by the grant of the Russian Ministry of Science # 3/1903.2017.
Transverse beam profile diagnostics based on Optical Transition Radiation (OTR) is a routine technique at most modern electron linear accelerators (linacs) which is difficult to implement for FEL beams [*] and LWPA accelerators [**]. The reason is that a standard OTR beam profile monitor with a few micrometers space resolution cannot be used for measurements of ultrashort bunch profiles due to coherent effects in the OTR emission process [***]. We have developed an approach which allows calculating the propagation of coherent optical transition radiation (COTR) through a standard optical system consisting of a focusing lens and a spatial resolving detector placed in the image plane. Strict summation of the OTR fields emitted coherently by electrons inside the bunch and its focusing onto the detector plane allows obtaining a COTR image of the bunch profile. With the assumption of a Gaussian transverse bunch profile it is shown that the resulting image has a typical "ring" shape, characteristics of which are depended on the bunch transverse rms size and optical system parameters.
* E. Saldin, et al., "The Physics of Free Electron Lasers", Springer-Verlag, 2010.
** N. Bourgeois, et al., AIP Conf. Proc., 1507, 258 (2012).
*** H. Loos, R. Akre, et al., SLAC-PUB-13395 (2008).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP012  
About • paper received ※ 04 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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TUPP013 Slit-Based Slice Emittance Measurements Optimization at PITZ emittance, quadrupole, electron, cathode 313
 
  • R. Niemczyk, P. Boonpornprasert, Y. Chen, J.D. Good, M. Groß, H. Huck, I.I. Isaev, C. Koschitzki, M. Krasilnikov, S. Lal, X. Li, O. Lishilin, G. Loisch, D. Melkumyan, A. Oppelt, H.J. Qian, H. Shaker, G. Shu, F. Stephan, G. Vashchenko
    DESY Zeuthen, Zeuthen, Germany
  • W. Hillert
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
 
  At the Photo Injector Test Facility at DESY in Zeuthen (PITZ) high-brightness electron sources are optimized for use at the X-ray free-electron lasers FLASH and European XFEL. Transverse projected emittance measurements are carried out by a single-slit scan technique in order to suppress space charge effects at an energy of ~20 MeV. Previous slice emittance measurements, which employed the emittance measurement in conjunction with a transverse deflecting structure, suffer from limited time resolution and low signal-to-noise ratio (SNR) due to a long drift space from the mask to the observation screen. Recent experimental studies at PITZ show improvement of the temporal resolution and SNR by utilizing quadrupole magnets between the mask and the screen. The measurement setup is described and first results are shown.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP013  
About • paper received ※ 26 August 2019       paper accepted ※ 09 September 2019       issue date ※ 10 November 2019  
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TUPP014 New Combined Function Wire Scanner-Screen Station for the High Resolution Transverse Profile Measurements at FERMI electron, FEL, vacuum, operation 317
 
  • M. Veronese, A. Abrami, M. Bossi, M. Ferianis, S. Grulja, G. Penco, M. Tudor
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
 
  We present the upgrade of the transverse profile diagnostics at the end of the FERMI Linac with a new high resolution instrumentation with the aim of improving the accuracy of the measurement of the twiss parameters and of the emittance. A scintillating screen, has been adopted instead of OTR screen due to known COTR issues. We used the same COTR suppression geometry that we had already implemented on our intra undulator screens and YAG:Ce as scintillating material. Screen based transverse profile diagnostics provide single shot measurements with a typical resolution of the order of tens of microns mainly due to refraction effects, geometry and other physical material properties. To extend the resolution to the micron level needed in case of low charge operation, we have equipped the same vacuum chamber with a wire scanner housing 10 micron tungsten wires. This paper describes the design and the first operational experience with the new device and discusses advantages as well as limitations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP014  
About • paper received ※ 04 September 2019       paper accepted ※ 09 September 2019       issue date ※ 10 November 2019  
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TUPP028 Double-Wire Vibrating Wire Monitor (DW-VWM) for Beam Halo Monitoring in High-intensity Accelerators vacuum, experiment, electron, operation 368
 
  • D.H. Kwak, M. Chung
    UNIST, Ulsan, Republic of Korea
  • S.G. Arutunian, A.V. Margaryan
    ANSL, Yerevan, Armenia
  • G.S. Harutyunyan, E.G. Lazareva
    YSU, Yerevan, Armenia
 
  Funding: This work was partly supported by the National Research Foundation of Korea (Grants No. 2017M1A7A1A02016413).
Double-Wire Vibrating Wire Monitor (DW-VWM) has been designed and manufactured to monitor the beam halo in high-intensity accelerators. Compared with the previous VWM, we increase the ratio between the aperture and wire length by using strong 5 mm x 5 mm Samarium-Cobalt magnets. In addition, we install two stainless steel vibrating wires on the same frame. The first wire is placed in the beam halo region for measurements, and the second wire, which is separated from the beam by a screen, is used to subtract background signal caused by ambient temperature shifts. The new electronics of the DW-VWM consist of two main boards: auto-generation unit which is placed near the VWM, and the frequency measurement unit which is placed in the control room (100 m distance operation was tested). Typical frequency of the VWM (at start tension about 0.7 of tensile strength) is about 8000 Hz. The temperature sensitivity is about 110 Hz/K with 0.2 mK Hz resolution. The VWM was tested in vacuum tank and the frequency corresponding to each vacuum level was analyzed. The process of oscillation excitation at different levels of vacuum was also investigated.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP028  
About • paper received ※ 04 September 2019       paper accepted ※ 11 September 2019       issue date ※ 10 November 2019  
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TUPP033 Laboratory and Beam Based Studies for Assessing the Performance of the New Fast Wire Scanners for the CERN Injector Complex controls, feedback, operation, emittance 387
 
  • J. Emery, P. Andersson, W. Andreazza, J.M. Fernandez Ochoa, A. Goldblatt, D. Gudkov, F. Roncarolo, J.L. Sirvent, J. Tassan-Viol, R. Veness
    CERN, Geneva, Switzerland
 
  At CERN, fast beam wire scanners serve as reference transverse profile monitors in all synchrotrons. As part of the LHC Injector Upgrade project, a new generation of scanners has been designed to improve system reliability, precision and accuracy in view of higher brightness beams. This paper will discuss the performance achieved during both laboratory calibration and prototype testing with beam. The beam measurements performed in 2018 demonstrated excellent system reliability and reproducibility, while calibration in the laboratory showed that an accuracy below 10 um can be achieved on the wire position determination.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP033  
About • paper received ※ 04 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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TUPP043 Fast and Robust Wire Scanners with Novel Materials for Profiling High Intensity Beams operation, controls, detector, diagnostics 433
 
  • G. Andonian, T.J. Campese, A. Laurich, M. Ruelas
    RadiaBeam, Marina del Rey, California, USA
  • G. Andonian, J.K. Penney
    UCLA, Los Angeles, California, USA
  • J. Gubeli, K. Jordan, J. Yan
    JLab, Newport News, Virginia, USA
  • C.F. Huff, L.R. Scammell, R.R. Whitney
    BNNT, LLC, Newport News, USA
 
  Wire scanners are robust devices for beam characterization in accelerator facilities. However, prolonged usage with intense particle beams leads to wire damage, requiring replacement and beam diagnostic downtime. The fast, robust wire scanner was recently designed and engineered with swappable and modular wire cards, that can accommodate different wire materials under tension. Testing is currently underway at the Jefferson Laboratory (JLab) Low Energy Recirculating Facility. During the course of the diagnostic development and commissioning, we will test Tungsten, Carbon, and boron-nitride nanotube in wire form. The latter is particularly relevant as early results on the material show that it has very high thermal thresholds and may withstand the high-power of the beam during regular operations. This paper will report on the system design and engineering, and preliminary results with operation on the beamline.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP043  
About • paper received ※ 05 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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WEAO04 Beam Measurements at the CERN SPS Using Interferometric Electro-Optic Pickups pick-up, simulation, proton, luminosity 454
 
  • A. Arteche, A. Bosco, S.M. Gibson
    Royal Holloway, University of London, Surrey, United Kingdom
  • S.E. Bashforth, A. Bosco, S.M. Gibson
    JAI, Egham, Surrey, United Kingdom
  • M. Krupa, T. Lefèvre
    CERN, Geneva, Switzerland
 
  Funding: Work supported by UK STFC grants ST/N001583/1, JAI at Royal Holloway University of London and CERN.
Since 2016 a prototype electro-optic pickup has been installed on the SPS as part of the ongoing development of a high bandwidth electro-optic beam position monitor for the High Luminosity LHC. Following the success of initial beam signal observations with the prototype, improvements of the sensitivity and stability of the pickup have become the main focus of the project. A new concept has been developed which uses an interferometric technique to measure the image field of a passing bunch. One arm of an interferometer passes through an electro-optic lithium niobate crystal, embedded in a pickup, whereas the other arm bypasses. The recombination after the pickup results in an interference pattern that changes as a bunch passes by, due to the electro-optic response of the crystal to the image field. This technique enhances the sensitivity to the field and improves control of the working point. Results from high intensity beams at the SPS are presented. These include a comparison between two different interferometric configurations that were tested on different pickups with similar beam conditions. The stability is assessed by frequency scanning interferometry during beam operation.
 
slides icon Slides WEAO04 [52.252 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEAO04  
About • paper received ※ 10 September 2019       paper accepted ※ 12 September 2019       issue date ※ 10 November 2019  
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WEPP018 THz Generation by Optical Rectification for a Novel Shot to Shot Synchronization System Between Electron Bunches and Femtosecond Laser Pulses in a Plasma Wakefield Accelerator plasma, electron, wakefield, optics 548
 
  • S. Mattiello, A. Penirschke
    THM, Friedberg, Germany
  • H. Schlarb
    DESY, Hamburg, Germany
 
  Funding: The work of S. Mattiello is supported by the German Federal Ministry of Education and Research (BMBF) within the Project ’ MAKE-PWA.
We investigate the influence of the optical properties and of the theoretical description of the THz generation on the conversion efficiency of the generation of short THz pulses. The application is a feedback-system for SINBAD with a time resolution of less than 1 fs for the synchronization of the electron bunch and of the plasma wake field in a laser driven plasma particle accelerator*. Here stable THz pulses are generated by optical rectification of a fraction of the plasma generating high energy laser pulses in a nonlinear lithium niobate crystal. Then the generated THz pulses will energy modulate the electron bunches shot to shot before the plasma to achieve the required time resolution. In this contribution we compare different approximations for the modeling of the generation dynamics using second order or first order equations as well as considering pump depletion effects. Additionally, the dependence of the efficiency of the THz generation on the choice of the dielectric function has been investigated.
*The feedback system will be tested at the Accelerator R&D facility SINBAD (Short Innovative Bunches and Accelerators at DESY).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP018  
About • paper received ※ 04 September 2019       paper accepted ※ 09 September 2019       issue date ※ 10 November 2019  
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WEPP019 Concept of a Novel High-Bandwidth Arrival Time Monitor for Very Low Charges as a Part of the All-Optical Synchronization System at ELBE pick-up, electron, FEL, FEM 553
 
  • A. Penirschke
    THM, Friedberg, Germany
  • W. Ackermann
    TEMF, TU Darmstadt, Darmstadt, Germany
  • M.K. Czwalinna, H. Schlarb
    DESY, Hamburg, Germany
  • M. Kuntzsch
    HZDR, Dresden, Germany
 
  Funding: This work is supported by the German Federal Ministry of Education and Research (BMBF) under contract no. 05K19RO1.
Numerous advanced applications of X-ray free-electron lasers require pulse durations and time resolutions in the order of only a few femtoseconds or better. The generation of these pulses to be used in time-resolved experiments require synchronization techniques that can simultaneously lock all necessary components to a precision in the range of a few fs only. The CW operated electron accelerator ELBE at the Helmholtzzentrum Dresden Rossendorf uses a all-optical synchronization system to ensure a timing stability on the few 10 fs scale. ELBE requires a minimum beam pipe diameter of 43mm that limits the achievable output voltage of the pickup structure to drive the attached electro-optical modulator. This contribution presents a concept for a novel high-bandwidth arrival time monitor with sufficient output signal for the attached EOMs for very low charges as a part of the all-optical synchronization system at ELBE.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP019  
About • paper received ※ 04 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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WEPP020 First results on Femtosecond Level Photocathode Laser Synchronization at the SINBAD Facility timing, electron, controls, linac 557
 
  • M. Titberidze, M. Felber, T. Kozak, T. Lamb, J. Müller, H. Schlarb, S. Schulz, C. Sydlo, F. Zummack
    DESY, Hamburg, Germany
 
  SINBAD, the "short-innovative bunches and accelerators at DESY" is an accelerator research and development facility which will host various experiments. SINBAD-ARES linac is a conventional S-band linear accelerator which will be capable of producing ultra-short electron bunches with duration of few femtoseconds and energy of up to 100 MeV. In order to fully utilize the potential of ultra-short electron bunches while probing the novel acceleration techniques (e.g. external injection in LWFA), it is crucial to achieve femtosecond level synchronization between photocathode laser and RF source driving the RF gun of the ARES linac. In this paper we present the first results on the synchronization of the near-infrared photocathode laser to the RF source with the residual timing jitter performance of ~10 fs rms. These results were obtained using a conventional laser-to-RF synchronization setup employing heterodyne detection of an RF signal generated by impinging the laser pulses to a fast photodetector. In addition, we describe an advanced laser-to-RF phase detection scheme as a future upgrade; promising even lower timing jitter and most importantly the long-term timing drift stability.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP020  
About • paper received ※ 04 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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WEPP022 A Method of Correcting the Beam Transverse Offset for the Cavity Bunch Length Monitor cavity, simulation, dipole, impedance 565
 
  • Q. Wang, Q. Luo, B.G. Sun
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
 
  Funding: Supported by National Key R&D Program of China (Grant No. 2016YFA0401900 and No. 2016YFA0401903) and The National Natural Science Foundation of China (Grant No. U1832169 and No. 11575181)
Cavity bunch length monitor uses monopole modes excited by bunches within the cavities to measure the bunch longitudinal root mean square (rms) length. It can provide a very high accuracy and high resolution. However, when the bunch passes through the cavities with transverse offset (that is, the bunch moves off the cavity axis), the amplitude of the monopole modes will change and cannot reflect the bunch length precisely. In this paper, a method of correcting the beam transverse offset is proposed. Simulation results show that the method can reduce the error of the bunch length measurement significantly.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP022  
About • paper received ※ 03 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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WEPP028 Laser Compton Backscattering Source for Beam Diagnostics at the S-DALINAC electron, photon, linac, scattering 575
 
  • M.G. Meier, M. Arnold, J. Enders, N. Pietralla, M. Roth
    TU Darmstadt, Darmstadt, Germany
  • V. Bagnoud
    GSI, Darmstadt, Germany
 
  Funding: Supported in part through the state of Hesse (LOEWE research cluster Nuclear Photonics) and DFG through GRK 2128 ’AccelencE’.
The Superconducting DArmstadt electron LINear ACcelerator S-DALINAC is a thrice-recirculating linac* providing electron beams with energies up to 130 MeV and beam currents up to 20 ’A for a variety of nuclear physics experiments**. It has been operated as Germany’s first energy-recovery linac (ERL) in 2017***. The electron beam is produced either in a thermionic gun or a DC photo-gun using GaAs as cathode material****. A new project foresees to use the S-DALINAC for Laser Compton Backscattering (LCB) to produce a monochromatic high-energy photon beam for nuclear photonics applications in photonuclear reactions and atomics physics experiments. Besides this LCB will be used as an additional diagnostic tool for determining electron beam energy and the energy spread at the third recirculation of the S-DALINAC, when the maximum reachable energy at this point (98.8 MeV) yields a scattered photon energy of 179.7 keV. An overview over the desired laser system for LCB at the S-DALINAC will be given, and simulations for the layout and the estimated output of the Compton-backscattering light source will be presented.
*M. Arnold, Diss., TU Darmstadt (2017)
**N. Pietralla, Nucl. Phys. News 28(2), 4(2018)
***M. Arnold et al., Proc. IPAC’18(4859), 9(2018)
****Y. Poltoratska et al., J.Phys.: Conf. S. 298, 012002(2011)
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP028  
About • paper received ※ 04 September 2019       paper accepted ※ 11 September 2019       issue date ※ 10 November 2019  
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WEPP031 Long Beam Pulse Extraction by the Laser Charge Exchange Method Using the 3-MeV Linac in J-Parc linac, proton, experiment, extraction 589
 
  • H. Takei, K. Hirano, S.I. Meigo
    JAEA/J-PARC, Tokai-mura, Japan
  • K. Tsutsumi
    Nippon Advanced Technology Co., Ltd., Tokai, Japan
 
  The Accelerator-driven System (ADS) is one of the candidates for transmuting long-lived nuclides, such as minor actinide (MA), produced by nuclear reactors. For efficient transmutation of the MA, a precise pre-diction of neutronics of ADS is required. In order to obtain the neutronics data for the ADS, the Japan Pro-ton Accelerator Research Complex (J-PARC) has a plan to build the Transmutation Physics Experimental Facility (TEF-P), in which a 400-MeV negative proton (H) beam will be delivered from the J-PARC linac. Since the TEF-P requires a stable proton beam with a power of less than 10 W, a stable and meticulous beam extraction method is required to extract a small amount of the proton beam from the high power beam of 250 kW. To fulfil this requirement, the Laser Charge Exchange (LCE) method has been developed. To demonstrate the long beam pulse extraction using the bright continuous laser beam with a power of 196 W, we installed the LCE device at the end of a 3-MeV linac. As a result of the experiment, a charge-exchanged proton beam with a power of 0.67 W equivalent was obtained under the J-PARC linac beam condition, and this value agreed well with the theoretical value.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP031  
About • paper received ※ 04 September 2019       paper accepted ※ 09 September 2019       issue date ※ 10 November 2019  
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WEPP039 Single-Shot Diagnostics of Microbunched Electrons in Laser-Driven Plasma Accelerators and Free-Electron Lasers electron, diagnostics, radiation, experiment 628
 
  • A.H. Lumpkin
    Fermilab, Batavia, Illinois, USA
  • D.W. Rule
    Private Address, Silver Spring, USA
 
  Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
The need for single-shot diagnostics of the periodic longitudinal density modulation of relativistic electrons at the resonant wavelength (microbunching) in a free-electron laser (FEL) or at broadband visible wavelengths as in a laser-driven plasma accelerator (LPA) has been reaffirmed. In the self-amplified spontaneous emission (SASE) FEL case, statistical fluctuations in the microbunching occur in the startup-from-noise process. In the LPA, the plasma itself is chaotic and varies shot to shot. Fortunately, we have shown that coherent optical transition radiation (COTR) techniques, can assess beam size, divergence, spectral evolution, and z-dependent gain (100, 000) of microbunched electrons in a past SASE FEL experiment at 530 nm*. Recently, the application to LPAs has been demonstrated with single-shot near-field (NF) and far-field (FF) COTR imaging done at the exit of an LPA for the first time**. In this case few-micron beam sizes and extensive fringes due to sub-mrad divergences were measured based on point-spread-function effects and an analytical model for COTR interferometry, respectively. A proposed diagnostics application at 266 nm to pre-bunched beams is also described.
*A.H. Lumpkin et al., Phys. Rev. Lett. 88, No.23, 234801 (2002).
**A.H. Lumpkin, M. LaBerge, D.W. Rule, et al., Proceedings of AAC18, (IEEE), 2019.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP039  
About • paper received ※ 10 September 2019       paper accepted ※ 11 September 2019       issue date ※ 10 November 2019  
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