Time Resolved Diagnostics and Synchronization
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MOPG50 Deflecting Cavity Dynamics for Time-Resolved Machine Studies of SXFEL User Facility 169
  • M. Song, H.X. Deng, B. Liu, D. Wang
    SINAP, Shanghai, People's Republic of China
  Radio frequency deflectors are widely used for time-resolved beam energy, emittance and radiation profile measurements in modern free electron laser facilities. Here, we present the beam dynamics aspects of the deflecting cavity of SXFEL user facility. With a targeted time resolution around 10 fs, it is expected to be an important tool for time-resolved machine studies for SXFEL user facility.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG50  
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MOPG51 Electron Beam Longitudinal Diagnostic With Sub-Femtosecond Resolution 173
  • G. Andonian, M.A. Harrison, F.H. O'Shea, A.G. Ovodenko
    RadiaBeam, Santa Monica, California, USA
  • J.P. Duris, J.B. Rosenzweig, N.S. Sudar
    UCLA, Los Angeles, California, USA
  • M.G. Fedurin, K. Kusche, I. Pogorelsky, M.N. Polyanskiy, C. Swinson
    BNL, Upton, Long Island, New York, USA
  • M.K. Weikum
    DESY, Hamburg, Germany
  Ultra-short, high brightness electron beams, with applications to next generation light sources or advanced accelerators, require enhanced resolution of the longitudinal bunch properties to study effects such as the micro-bunching instability. In this paper, we describe a diagnostic that has the promise to achieve sub-femtosecond longitudinal resolution. The diagnostic employs a laser-electron beam interaction in an undulator magnet in tandem with a RF bunch deflecting cavity to impose a angular-longitudinal coordinate correlation on the bunch which is resolvable with standard optical systems. The fundamental underlying concepts of the diagnostic have been tested experimentally at the Brookhaven National Laboratory Accelerator Test Facility (BNL ATF) with the high-brightness electron beam and >100GW IR laser operating in the TEM10 mode. The results include a systematic study of the effects of this laser mode, and energy, on the beam angular projection. Initial runs from the x-band deflecting cavity will also be presented here.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG51  
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MOPG52 Simulation of THz Streak Camera Performance for Femtosecond FEL Pulse Length Measurement 176
  • I. Gorgisyan, R. Ischebeck, P.N. Juranič, E. Prat, S. Reiche
    PSI, Villigen PSI, Switzerland
  • I. Gorgisyan
    EPFL, Lausanne, Switzerland
  Measurement of the temporal duration of FEL pulses is important both for the operators to monitor the performance of the machine and the users performing pump-probe measurements with FEL beam. The light-field streak camera is a promising methods for the photon pulse length measurement that uses the electric field of an IR/THz laser to streak the photoelectrons*. This contribution presents a simulation of the performance of a streak camera using a single-cycle THz pulse**. The simulation recreates the photoionization process and generates electron spectra in presence of the THz field and without it. Using these spectra the photon pulse lengths are calculated and compared to the initial values. Most of the parameters used in the simulation are chosen based on experiments performed earlier.*** This contribution presents the simulation method and the obtained results. It validates the pulse length calculation analysis method and estimates the expected measurement accuracy and precision for the THz streak camera measurement technique. The simulations were done for different FEL pulse lengths ranging from about 1 fs to 40 fs both in soft and hard X-ray range.
*J. Itatani et al, PRL 88,2002
*U. Fruhling et al, N. Phot. 3,2009
**I. Gorgisyan et al, JSR 3,2016
***P. N. Juranic et al, Opt. Exp. 22,2014
***P. N. Juranic et al, J. Inst. 9,2014
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG52  
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MOPG53 Electron Beam Probe Diagnostic for BESSY II Storage Ring 179
  • D. Malyutin, A.N. Matveenko
    HZB, Berlin, Germany
  A low energy electron beam can be used to characterize the high energy ultra-relativistic bunches. This technique allows one to obtain the bunch transverse profiles as well as the bunch length within a non-destructive single shot measurement. In this paper the bunch length measurement technique based on the interaction of the low energy electron beam with an ultra-relativistic bunch is described. Results of numerical simulations of measurements related to BESSY II are presented. A possible setup of such diagnostic system for BESSY II and in future for BESSY VSR is proposed.  
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MOPG54 Laser-Based Beam Diagnostics for Accelerators and Light Sources 183
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  Funding: This project has received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no 289191.
The Laser Applications at Accelerators network (LA≥NET) was selected for funding within the European Union's 7th Framework Programme. During its 4 year duration the project has successfully trained 19 Fellows and organized numerous events that were open to the wider laser and accelerator communities. The network linked research into lasers and accelerators to develop advanced particle sources, new accelerating schemes, and in particular beyond state-of-the-art beam diagnostics. This contribution summarizes the research results in laser-based beam diagnostics for accelerators and light sources. It discusses the achievable resolution of laser-based velocimeters to measure the velocity of particle beams, the resolution limits of bunch shape measurements using electro-optical crystals, position resolution of laser wire scanners, and limits in energy measurements using Compton backscattering at synchrotron light sources. Finally, it also provides a summary of past and future events organized by the network and shows how an interdisciplinary research program can provide comprehensive training to a cohort of early career researchers.
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MOPG55 Streak Camera Calibration Using RF Switches 186
  • U. Iriso, M. Alvarez, A.A. Nosych
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  • A. Molas
    UAB, Barcelona, Spain
  The streak camera has been used to measure the bunch length since the ALBA storage ring commissioning in 2011. Previously, we developed an optical calibration system based on the Michelson interferometry. Similar to the work at the DLS*, in this report we show the calibration kit based on the different electrical delays which can be used via rf switches. We compare both calibration systems and we show measurements of the longitudinal impedance obtained with the new calibration.
*L. Bobb, A. Morgan, and G. Rehm, "Streak Camera PSF optimisation and udal sweep calibration for sub-ps bunch length measurements", Proc. of IBIC2015 (Australia)
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MOPG56 Development of Accelerator System and Beam Diagnostic Instruments for Natural Rubber and Polymer Research 190
  • E. Kongmon, N. Kangrang, S. Rimjaem, J. Saisut, C. Thongbai
    Chiang Mai University, Chiang Mai, Thailand
  • M.W. Rhodes
    ThEP Center, Commission on Higher Education, Bangkok, Thailand
  • P. Wichaisirimongkol
    Chiang Mai University, Science and Technology Research Institute, Chiang Mai, Thailand
  This research aims to design and develop an elec-tron linear accelerator system and beam diagnostic instruments for natural rubber and polymer research at the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The accelerator con-sists of a DC thermionic electron gun and an S-band standing-wave linac. The system can produce electron beams with the energy range of 0.5 to 4 MeV for the pulse repetition rate of 30 to 200 Hz and the pulse duration of 4 μs. Commissioning of the accelerator system and development of beam diagnostic instru-ments to measure electron beam energy, electron pulse current and electron dose are underway. This contribu-tion presents and discusses on the RF commissioning progress as well as status of design and construction of the beam diagnostic system.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG56  
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MOPG57 Temperature and Humidity Drift Characterization of Passive RF Components for a Two-Tone Calibration Method 194
  • E. Janas, K. Czuba
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
  • E. Janas, U. Mavrič, H. Schlarb
    DESY, Hamburg, Germany
  Femtosecond-level synchronization is required for various systems in modern accelerators especially in fourth generation light sources. In those high precision synchronization systems the phase detection accuracy is crucial. However, synchronization to a low noise electrical source is corrupted by a phase detection error originating in the electrical components and connections due to thermal and humidity-related drifts. In future, we plan to implement calibration methods to mitigate these drifts. Those methods require a calibration signal injection, called second tone, into the system. Intrinsically, the injection circuit remains uncalibrated therefore it needs to be drift-free. We performed drift characterization of a set of RF components, which could serve for implementation of a signal injection circuit, namely selected types of couplers and splitters. We describe the measurement setup and discuss the challenges associated with this kind of measurement. Finally, we provide a qualitative and quantitative evaluation of the measurements results.  
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MOPG58 Coherent Diffraction Radiation Imaging Methods to Measure RMS Bunch 198
  • R.B. Fiorito, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • C.I. Clarke, A.S. Fisher
    SLAC, Menlo Park, California, USA
  • A.G. Shkvarunets
    UMD, College Park, Maryland, USA
  The measurement of the RMS bunch length with high resolution is very important for latest generation light sources and also a key parameter for the optimization of the final beam quality in high gradient plasma accelerators. In this contribution we present progress in the development of novel single shot, RMS bunch length diagnostic techniques based on imaging the near and far fields of coherent THz diffraction radiation (CTHzDR) that is produced as a charged particle beam interacts with a solid foil or an aperture. Recent simulation results show that the profile of a THz image of the coherent point spread function (CSF) of a beam whose radius is less than the PSF, i.e. the image produced by a single electron, is sensitive to bunch length and can thus be used as a diagnostic. The advantages and disadvantages of near field and far field imaging are examined and the results of a recent high energy (20 GeV) CTHzDR experiments at SLAC/FACET are presented. Plans for experiments to further validate and compare these imaging methods for both moderate and high energy charged particle beams are also discussed.  
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MOPG59 Time Correlated Single Photon Counting Using Different Photon Detectors 201
  • L. Torino, U. Iriso
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  Time Correlated Single Photon Counting (TCSPC) is used in accelerators to measure the filling pattern and perform bunch purity measurements. The most used photon detectors are photomultipliers (PMTs), generally used to detect visible light; and Avalanche Photo-Diodes (APDs), which are often used to detect X-rays. At ALBA synchrotron light source, the TCSPC using a standard PMT has been developed and is currently in operation and further tests are performed using an APD. This work presents the experimental results using both detectors, and compares their performances.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG59  
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MOPG60 Development, Calibration and Application of New-Generation Dissectors With Picosecond Temporal Resolution 205
  • O.I. Meshkov, O. Anchugov, G.Y. Kurkin, A.V. Petrozhitskii, D.A. Shvedov, E.I. Zinin
    BINP SB RAS, Novosibirsk, Russia
  • V.L. Dorokhov
    BINP, Novosibirsk, Russia
  • P.B. Gornostaev, M.Ya. Schelev, E.V. Shashkov, A. V. Smirnov, A.I. Zarovskii
    GPI, Moscow, Russia
  A dissector is an electron-optical device designed for measurement of periodic light pulses of subnanosecond and picosecond duration. LI-602 dissector developed at BINP SB RAS is widely used for routine measurements of a longitudinal profile of electron and positron beams at BINP electron-positron colliders and other similar installations. LI-602 dissector is a part of many optical diagnostic systems and provides temporal resolution of about 20 ps. Recently a new generation of picosecond dissectors were created on the basis of the PIF-01/S1 picosecond streak-image tube designed and manufactured at the GPI Photoelectronics Department. The results of the measurements of instrument function of the new dissector based on PIF-01/S1, which were carried out in the static mode, showed that temporal resolution of the dissector can be better than 3-4 ps (FWHM). The results of temporal resolution calibration of the new-generation picosecond dissector, carried out at the specialized set-up based on a femtosecond Ti:sapphire laser, and recent results of longitudinal beam profile measurements at BINP accelerators are given in this work.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG60  
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MOPG62 Novel Grating Designs for a Single-Shot Smith-Purcell Bunch Profile Monitor 213
  • A.J. Lancaster, G. Doucas, H. Harrison, I.V. Konoplev
    JAI, Oxford, United Kingdom
  Funding: This work was supported by the STFC UK (grant ST/M003590/1) and the Leverhulme Trust (International Network Grant IN-2015-012). H. Harrison is supported by STFC UK and the JAI for her DPhil.
Smith-Purcell radiation has been successfully used to perform longitudinal profile measurements of electron bunches with sub-ps lengths. These measurements require radiation to be generated from a series of gratings to cover a sufficient frequency range for accurate profile reconstruction. In past systems the gratings were used sequentially and so several bunches were required to generate a single profile, but modern accelerators would benefit from such measurements being performed on a bunch by bunch basis. To do this the radiation from all three gratings would need to be measured simultaneously, increasing the mechanical complexity of the device as each grating would need to be positioned individually and at a different azimuthal angle around the electron beam. Investigations into gratings designed to displace the radiation azimuthally will be presented. Such gratings could provide an alternative to the rotated-grating approach, and would simplify the design of the single-shot monitor by reducing the number of motors required as all of the gratings could be positioned using a single mount.
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Temporal Profile Measurements of Relativistic Electron Bunch Based on Wakefield Generation  
  • S. Bettoni, P. Craievich, M. Pedrozzi
    PSI, Villigen PSI, Switzerland
  • A.A. Lutman
    SLAC, Menlo Park, California, USA
  A full characterization of the beam longitudinal phase space is crucial for the optimization of the performances of Free Electron Laser facilities, which require very short bunches to reach the time resolution for experiments of physics, biology and material science. We studied a novel approach to perform time-resolved measurements of a relativistic electron bunch based on the self-transverse wakefield interaction of the beam itself passing off-axis through a dielectric-lined or corrugated waveguide. The method is passive, can reach sub-fs resolution, and does not suffer of jitter issues. The main limitation is the poor resolution at the head of the bunch. We present simulations and a proof-of-principle experiment carried out at the SwissFEL injector test facility as well.  
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TUBL03 Synchronous Laser-Microwave Network for Attosecond-Resolution Photon Science 286
  • K. Shafak, F.X. Kärtner, A. Kalaydzhyan, O.D. Mücke, W. Wang, M. Xin
    CFEL, Hamburg, Germany
  • F.X. Kärtner, M.Y. Peng, M. Xin
    MIT, Cambridge, Massachusetts, USA
  Funding: This work was supported by the Center for Free-Electron Laser Science at Deutsches Elektronen-Synchrotron, a research center of the Helmholtz Association in Germany.
Next-generation photon-science facilities such as X-ray free-electron lasers (X-FELs)* and intense-laser beamline centers** are emerging world-wide with the goal of generating sub-fs X-ray pulses with unprecedented brightness to capture ultrafast chemical and physical phenomena with sub-atomic spatiotemporal resolution. The only obstacle preventing this long-standing scientific dream to come true is a high- precision timing distribution system*** synchronizing various microwave and optical sub-sources across multi-km distances which is required for seeded X-FELs and attosecond pump-probe experiments. Here, we present, for the first time, a synchronous laser-microwave network that will enable attosecond precision photon science facilities. By developing new ultrafast metrological timing devices and carefully balancing fiber nonlinearities and fundamental noise contributions, we have achieved timing stabilization of a 4.7 km fiber network with 580 attosecond precision over 52 hours. Furthermore, we have realized a complete laser-microwave network incorporating two mode-locked lasers and one microwave source with total 950 attosecond jitter integrated from 1 microsecond to 18 hours.
*J. Stohr, LCLS-II Conceptual Design Report. No. SLAC-R-978. (SLAC, 2011).
**G. Mourou, T. Tajima, Optics & Photonics News 22, 47 (2011).
***J. Kim, et al., Nat. Photonics 2(12), 733-736 (2008).
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TUBL04 Electro-Optical Methods for Multipurpose Diagnostics 290
  • R. Pompili, M.P. Anania, M. Bellaveglia, F.G. Bisesto, E. Chiadroni, A. Curcio, D. Di Giovenale, G. Di Pirro, M. Ferrario
    INFN/LNF, Frascati (Roma), Italy
  • A. Cianchi
    INFN-Roma II, Roma, Italy
  • A. Zigler
    The Hebrew University of Jerusalem, The Racah Institute of Physics, Jerusalem, Israel
  Electro-optic sampling (EOS) based temporal diagnostics allows to precisely measure the temporal profile of electron bunches with resolution of about 50 fs in a non-destructive and single-shot way. At SPARC_LAB we adopted the EOS in very different experimental fields. We measured for the first time the longitudinal profile of a train of multiple bunches at THz repetition rate, as the one required for resonant Plasma Wakefield Acceleration (PWFA) in a single-shot and non-intercepting way. By means of the EOS we demonstrated a new hybrid compression scheme that is able to provide ultra-short bunches (<90 fs) with ultra-low (<20 fs) timing-jitter relative to the EOS laser system. Furthermore, we recently developed an EOS system in order to provide temporal and energy measurements in a very noisy and harsh environment: electron beams ejected by the interaction of high-intensity (hundreds TW class) ultra-short (35fs) laser pulses with solid targets by means of the so-called Target Normal Sheath Acceleration (TNSA) method.  
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TUPG53 Bunch Arrival-Time Monitoring for Laser Particle Accelerators and Thomson Scattering X-Ray Sources 468
  • J.M. Kraemer, M. Kuntzsch, U. Lehnert, P. Michel, U. Schramm
    HZDR, Dresden, Germany
  • J.P. Couperus, A. Irman, A. Koehler, O. Zarini
    Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
  The ELBE center of high power radiation sources at Helmholtz-Zentrum Dresden-Rossendorf combines a superconducting CW linear accelerator with Terawatt- and Petawatt-level laser sources. Key experiments rely on precise timing and synchronization between the different radiation pulses. An online single shot monitoring system has been set up in order to measure the timing between the high-power Ti:Sa laser DRACO and electron bunches generated by the conventional SRF accelerator. This turnkey timing system is suitable for timing control of Thomson scattering X-ray sources and external injection of electron bunches into a laser wakefield accelerator. It uses a broadband RF pickup to acquire a probe of the particle bunch's electric field and modulates a fraction of the high power laser pulse in a fast electro-optical modulator. The amplitude modulation gives a direct measure for the timing between both beams. Using this setup a resolution of <200 fs RMS has been demonstrated. The contribution will show the prototype, first measurement results and will discuss future modification in order to improve the resolution of the system.  
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TUPG54 Novel Approach to the Elimination of Background Radiation in a Single-Shot Longitudinal Beam Profile Monitor 471
  • H. Harrison, G. Doucas, I.V. Konoplev, A.J. Lancaster, H. Zhang
    JAI, Oxford, United Kingdom
  • A. Aryshev, M. Shevelev, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  It is proposed to use the polarization of coherent Smith-Purcell radiation (cSPr) to distinguish between the cSPr signal and background radiation in a single-shot longitudinal bunch profile monitor. A preliminary measurement of the polarization has been carried out using a 1mm periodic metallic grating installed at the 8MeV electron accelerator LUCX, KEK (Japan). The measured degree of polarization at '=90° (300GHz) is 72.6 ±%. To make a thorough test of the theoretical model, measurements of the degree of polarization must be taken at more emission angles - equivalent to more frequencies.
This work was supported (in parts) by the: STFC UK, the Leverhulme Trust, JAI University of Oxford and the Photon and Quantum Basic Research Coordinated Development (Japan).
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TUPG56 Design of a Time-resolved Electron Diagnostics Using THz Fields Excited in a Split Ring Resonator at FLUTE 475
  • M. Yan, E. Bründermann, S. Funkner, A.-S. Müller, M.J. Nasse, G. Niehues, R. Ruprecht, M. Schedler, T. Schmelzer, M. Schuh, M. Schwarz, B. Smit
    KIT, Karlsruhe, Germany
  • M.M. Dehler, N. Hiller, R. Ischebeck, V. Schlott
    PSI, Villigen PSI, Switzerland
  • T. Feurer, M. Hayati
    Universität Bern, Institute of Applied Physics, Bern, Switzerland
  Time-resolved electron diagnostics with ultra-high temporal resolution is increasingly required by the state-of-the-art accelerators. Strong terahertz (THz) fields, excited in a split ring resonator (SRR), have been recently proposed to streak electron bunches for their temporal characterisation. Thanks to the high amplitude and frequency of the THz field, temporal resolution down to the sub-femtosecond range can be expected. We are planning a proof-of-principle experiment of the SRR time-resolved diagnostics at the accelerator test-facility FLUTE (Ferninfrarot Linac und Test Experiment) at the Karlsruhe Institute of Technology. The design of the experimental chamber has been finished and integrated into the design layout of the FLUTE accelerator. Beam dynamics simulations have been conducted to investigate and optimise the performance of the SRR diagnostics. In this paper, we present the design layout of the experimental setup and discuss the simulation results for the optimised parameters of the accelerator and the SRR structure.  
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TUPG57 5 MeV Beam Diagnostics at the Mainz Energy-Recovering Superconducting Accelerator MESA 479
  • S. Heidrich, K. Aulenbacher
    IKP, Mainz, Germany
  Within the next few years a new energy recovering superconducting electron accelerator will be built at the institute for nuclear physics in Mainz. To adjust the properties of the beam correctly to the first acceleration in the superconducting cavities, a high resolution longitudinal beam diagnosis is required at the 5 MeV injection arc. The system employs two 90-degree vertical deflection dipoles to achieve an energy resolution of 500 eV and a phase resolution of 60 micrometers. As a second challenge the transverse emittance measurements will take place at full beam current. This demands an extremely heat resistant diagnosis system, realized by a method similar to flying wire.  
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TUPG58 Measurement of Femtosecond Electron Beam Based on Frequency and Time Domain Schemes 483
  • K. Kan, M. Gohdo, T. Kondoh, I. Nozawa, J. Yang, Y. Yoshida
    ISIR, Osaka, Japan
  Ultrashort electron beams are essential for light sources and time-resolved measurements. Electron beams can emit terahertz (THz) pulses using coherent transition radiation (CTR). Michelson interferometer* is one of candidates for analyzing the pulse width of an electron beam based on frequency-domain analysis. Recently, electron beam measurement using a photoconductive antenna (PCA)** based on time-domain analysis has been investigated. The PCA with enhanced radial polarization characteristics enabled time-domain analysis for electron beam because of radially polarized THz pulse of CTR. In this presentation, measurement of femtosecond electron beam with 35 MeV energy and < 1 nC from a photocathode based linac will be reported. Frequency- and time- domain analysis of THz pulse of CTR by combining the interferometer and PCA will be carried out.
* I. Nozawa, K. Kan et al., Phys. Rev. ST Accel. Beams 17, 072803 (2014).
** K. Kan et al., Appl. Phys. Lett. 102, 221118 (2013).
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TUPG59 Bunch Extension Monitor for LINAC of SPIRAL2 Project 486
  • R.V. Revenko, J.L. Vignet
    GANIL, Caen, France
  A semi-interceptive monitor for bunch shape measure-ment has been developed for the LINAC of SPIRAL2. A Bunch Extension Monitor (BEM) is based on the registra-tion of X-rays emitted by the interaction of the beam ions with a thin tungsten wire. The time difference between detected X-rays and accelerating RF gives information about distribution of beam particles along the time axis. These monitors will be installed inside diagnostic boxes on the first five warm sections of the LINAC. The monitor consists of two parts: X-ray detector and mechanical system for positioning the tungsten wire into the beam. Emitted X-rays are registered by microchannel plates with fast readout. Signal processing is performed with constant fraction discriminators and TAC coupled with MCA. Results of bunch shape measurements obtained during commissioning of RFQ for SPIRAL2 are presented.  
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TUPG61 Stable Transmission of RF Signals and Timing Events With Accuracy at Femtoseconds 491
  • M. Liu, X.L. Dai, C.X. Yin
    SINAP, Shanghai, People's Republic of China
  Funding: Supported by the National Natural Science Foundation of China (No. 11305246) and the Youth Innovation Promotion Association CAS (No. 2016238).
We present a new design of femtosecond timing system. In the system, RF signal and timing events are transmitted synchronously in one single optical fiber with very high accuracy. Based on the theory of Michelson's interferometer, phase drift is detected with accuracy at femtoseconds. And phase compensation is accomplished in transmitter with two approaches afterwards. Moreover, the traditional event timing system is integrated into the new system to further reduce the jitter of timing triggers. The system could be applied in synchrotron light sources, free electron lasers and colliders, where distribution of highly stable timing information is required. The physics design, simulation analysis and preliminary results are demonstrated in the paper.
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG61  
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TUPG62 X-Ray Smith-Purcell Radiation for Non-Invasive Submicron Diagnostics of Electron Beams Having TeV Energy 494
  • A.A. Tishchenko, D.Yu. Sergeeva
    MEPhI, Moscow, Russia
  We present the general theory of X-ray Smith-Purcell radiation from ultrarelativistic beams proceeding from our earlier results. The theory covers also the case of oblique incidence of the beam to the target, which leads to the conical effect in spatial distribution of Smith-Purcell radiation and allows one to count the divergence of the beam; also, the analytical description of the incoherent form-factor of the beam is given.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG62  
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TUPG64 Bunch Length Measurement Based on Interferometric Technique by Observing Coherent Transition Radiation 498
  • I. Nozawa, M. Gohdo, K. Kan, T. Kondoh, J. Yang, Y. Yoshida
    ISIR, Osaka, Japan
  Generation and diagnosis of ultrashort electron bunches are one of the main topics of accelerator physics and applications in related scientific fields. In this study, ultrashort electron bunches with bunch lengths of femtoseconds and bunch charges of picocoulombs were generated from a laser photocathode RF gun linac and an achromatic arc-type bunch compressor. Observing coherent transition radiation (CTR) emitted from the electron bunches using a Michelson interferometer, the interferograms of CTR were measured experimentally. The bunch lengths were diagnosed by performing a model-based analysis of the interferograms of CTR.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG64  
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WEAL01 Longitudinal Diagnostics Methods and Limits for Hadron Linacs 563
  • A.P. Shishlo, A.V. Aleksandrov
    ORNL, Oak Ridge, Tennessee, USA
  Funding: This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC0500OR22725 with the U.S. Department of Energy. The United States Govern-ment retains and the publisher,
A summary of the longitudinal diagnostics for linacs is presented based on the Spallation Neutron Source (SNS) linac example. It includes acceptance phase scans, Bunch Shape Monitors (BSM), and a method based on the analysis of the stripline Beam Position Monitors (BPM) signals. The last method can deliver the longitudinal Twiss parameters of the beam. The accuracy, applicability, and limitations of this method are presented and discussed.
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEAL01  
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WECL01 Longitudinal Phase Space Diagnostics for Ultrashort Bunches With a Plasma Deflector 597
  • I. Dornmair, A.R. Maier
    CFEL, Hamburg, Germany
  • I. Dornmair
    University of Hamburg, Hamburg, Germany
  • K. Flöttmann, B. Marchetti
    DESY, Hamburg, Germany
  • A.R. Maier
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • C.B. Schroeder
    LBNL, Berkeley, California, USA
  We present with simulations a new method to diagnose the longitudinal phase space of ultrashort electron bunches. It harnesses the strong transverse fields of laser-driven wakefields to streak an electron bunch that is injected off-axis with respect to the driver laser. Owed to the short plasma wavelength and the high field amplitude present in a plasma wakefield, a temporal resolution around or below the femtosecond can be achieved with a plasma length of a few millimeters. We will explore the limitations on the time resolution, the calibration, and the influence of error sources such as beam loading and jitters. Amongst the possible applications are experiments aiming at external injection into laser-driven wakefields, or the diagnostics of laser-plasma accelerated beams.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WECL01  
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WEPG47 Progress on the PITZ TDS 744
  • H. Huck, P. Boonpornprasert, L. Jachmann, W. Köhler, M. Krasilnikov, A. Oppelt, F. Stephan
    DESY Zeuthen, Zeuthen, Germany
  • L.V. Kravchuk, V.V. Paramonov, A.A. Zavadtsev
    RAS/INR, Moscow, Russia
  • C. Saisa-ard
    Chiang Mai University, Chiang Mai, Thailand
  A transverse deflecting system (TDS) is under commissioning at the Photo Injector Test Facility at DESY, Zeuthen site (PITZ). The structure was designed and manufactured by the Institute for Nuclear Research (INR RAS, Moscow, Russia) as prototype for the TDS in the injector part of the European XFEL. Last year the deflection voltage was limited for safety reasons, but after thorough investigations of the waveguide system we are now able to operate the cavity close to design specifications. The PITZ TDS streaks the electron beam vertically, allowing measurements of the longitudinal bunch profile, and, in combination with a subsequent horizontal bending magnet, also of the longitudinal phase space and slice energy spread. Furthermore, several quadrupole magnets and screen stations can be employed for slice emittance measurements using the TDS. This paper describes the progress in commissioning of the hardware, measurement techniques and simulations, and outlines the prospects of reliable slice emittance measurements at 20 MeV/c, where space charge forces complicate the determination of transfer matrices.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG47  
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WEPG48 A THz Driven Transverse Deflector for Femtosecond Longitudinal Profile Diagnostics 748
  • S.P. Jamison, E.W. Snedden, D.A. Walsh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • M.J. Cliffe, D.M. Graham, D. Lake
    The University of Manchester, The Photon Science Institute, Manchester, United Kingdom
  Progress towards a THz-driven transverse deflecting longitudinal profile diagnostic is presented. The deflector is driven with sub-picosecond quasi-single cycle THz fields generated by non-linear optical rectification. To utilize the large deflection field strength of the source for longitudinal diagnostics it is necessary to maintain the single-cycle field profile of the THz pulse throughout the interaction with the relativistic beam. Our scheme allows for the octave spanning bandwidth of the single-cycle pulses to propagate without dispersion at subluminal velocities matched to co-propagating relativistic electrons, by passing the pulse distortion and group-carrier walk-off limitations of dielectric loaded waveguide structure. The phase velocity is readily tuneable, both above and below the speed of light in a vacuum, and single-cycle propagation of deflecting fields at velocities down to 0.77c have been demonstrated.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG48  
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WEPG49 A High Resolution Single-Shot Longitudinal Profile Diagnostic Using Electro-Optic Transposition 752
  • D.A. Walsh, S.P. Jamison, E.W. Snedden
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • T. Lefèvre
    CERN, Geneva, Switzerland
  Funding: This work was funded by CERN through contract KE1866/DG/CLIC and carried out at STFC Daresbury Laboratory.
Electro-Optic Transposition (EOT) is the basis for an improved longitudinal bunch profile diagnostic we are developing in ASTeC as part of the CLIC UK research program. The scheme consists of transposing the Cou-lomb field profile of an electron bunch into the intensity envelope of an optical pulse via the mixing processes that occur between a CW laser probe and Coulomb field in an electro-optic material. This transposed optical pulse can then be amplified and characterised using robust laser techniques ' in this case chirped pulse optical parametric amplification and frequency resolved optical gating, allowing the Coulomb field to be recovered. EOT is an improvement over existing techniques in terms of the achievable resolution which is limited by the EO material response itself, reduced complexity of the laser system required since nanosecond rather than femtosecond lasers are used, and insensitivity of the system to bunch-laser arrival time jitter due to using a nanosecond long probe. We present results showing the retrieval of a THz pulse (Coulomb field stand-in) which confirms the principle behind the EOT system.
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG49  
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WEPG50 Non-Invasive Bunch Length Diagnostics of Sub-Picosecond Beams 756
  • S.V. Kuzikov, A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
  • S.P. Antipov, S.V. Kuzikov
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • S.V. Kuzikov
    UNN, Nizhny Novgorod, Russia
  Funding: This work was partially supported by the Russian Scientific Foundation (grant #16-19-10448).
We propose a non-invasive bunch length measurement system based on RF pickup interferometry. A device performs interferometry between two broadband wake signals generated by a single short particle bunch. The mentioned wakes are excited by two consequent small gaps in beam channel. A field pattern formed by interference of the mentioned two coherent wake signals is registered by means of detector arrays placed at outer side of beam channel. The detectors are assumed to be low-cost integrating detectors (pyro-detectors or bolometers) so that integration time is assumed to be much bigger than bunch length. Because RF signals come from gaps to any detector with different time delays which depend on particular detector coordinate, the array allows to substitute measurements in time by measurements in space. Simulations with a 1 ps beam and a set of two 200 micron wide vacuum breaks separated by 0.5 mm were done using CST Particle Studio. These simulations show good accuracy. Moreover, one can recover the detailed temporal structure of the measured pulse using a new developed synthesis procedure.
poster icon Poster WEPG50 [2.780 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG50  
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WEPG51 A Transverse Deflecting Structure for the Plasma Wakefield Accelerator Experiment, FLASHForward 759
  • R.T.P. D'Arcy, V. Libov, J. Osterhoff
    DESY, Hamburg, Germany
  The FLASHForward project at DESY is an innovative plasma-wakefield acceleration experiment, aiming to accelerate electron beams to GeV energies over a few centimeters of ionized gas. These accelerated beams must be of sufficient quality to be used in a free-electron laser; achievable only through rigorous analysis of both the drive- and accelerated-beam's longitudinal phase space. The pulse duration of these accelerated beams is typically in the few femtosecond range, and thus difficult to resolve with traditional diagnostic methods. In order to longitudinally resolve these very short bunch-lengths, it is necessary to utilize the properties of a transverse RF deflector (operating in the hybrid electromagnetic mode, HEM11), which provides a relation between longitudinal and transverse co-ordinates. It is proposed that this type of device, commonly known as a Transverse Deflecting Structure (TDS) due to its 'streaking' in the transverse plane, will be introduced to the FLASHForward beamline in order to perform these single-shot longitudinal phase space measurements. The initial investigations into the realization of this diagnostic tool are outlined.  
poster icon Poster WEPG51 [10.726 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG51  
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WEPG52 Laser Arrival Time Measurement and Correction for the SwissFEL Lasers 763
  • M.C. Divall, C.P. Hauri, S. Hunziker, A. Romann, A. Trisorio
    PSI, Villigen PSI, Switzerland
  SwissFEL will ultimately produce sub-fs X-ray pulses. Both the photo-injector laser and the pump lasers used for the experimental end stations therefore have tight requirements for relative arrival time to the machine and the X-rays. The gun laser oscillator delivers excellent jitter performance at ~20fs integrated from 10Hz-10MHz. The Yb:CaF2 regenerative amplifier, with an over 1km total propagation path, calls for active control of the laser arrival time. This is achieved by balanced cross-correlation against the oscillator pulses and a translation stage before amplification. The experimental laser, based on Ti:sapphire laser technology will use a spectrally resolved cross-correlator to determine relative jitter between the optical reference and the laser, with fs resolution. To be able to perform fs resolution pump-probe measurements the laser has to be timed with the X-rays with <10fs accuracy. These systems will be integrated into the machine timing and complemented by electron bunch and X-ray timing tools. Here we present the overall concept and the first results obtained on the existing laser systems.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG52  
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WEPG53 Unambiguous Electromagnetic Pulse Retrieval Through Frequency Mixing Interference in Frequency Resolved Optical Gating 767
  • E.W. Snedden, S.P. Jamison, D.A. Walsh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • S.P. Jamison
    The University of Manchester, The Photon Science Institute, Manchester, United Kingdom
  We demonstrate a method for full and unambiguous temporal characterization of few-cycle electromagnetic pulses, including retrieval of the carrier envelope phase (CEP), in which the interference between non-linear frequency mixing components is spectrally resolved using Frequency Resolved Optical Gating (FROG). We term this process Real-Domain FROG (ReD-FROG) and demonstrate its capabilities through the complete measurement of the temporal profile of a single-cycle THz pulse. When applied at THz frequencies ReD-FROG overcomes the bandwidth limitations relating probe and test pulses in Electro-Optic (EO) sampling. The approach can however be extended generally to any frequency range and we provide a conceptual demonstration of the CEP retrieval of few-cycle optical field.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG53  
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WEPG54 Bunch Shape Measurements at the National Superconducting Cyclotron Laboratory ReAccelerator (ReA3) 771
  • R. Shane, S.M. Lidia, Z. Liu, S. Nash, A.C.C. Villari, O. Yair
    FRIB, East Lansing, USA
  Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University.
The longitudinal bunch shape of a reaccelerated heavy-ion beam at the National Superconducting Cyclo-tron Laboratory's (NSCL) ReA3 beamline was measured using an Ostrumov-type bunch-shape monitor. The phase of the last accelerating cavity was varied to change the bunch length, while the energy was kept constant by adjusting the amplitude of the voltage on the cavity. Two peaks were observed in the longitudinal projection of the bunch shape distribution. The widths of the two peaks did not vary much when the cavity phase was changed, while the peak separation decreased to the point that the two peaks became unresolvable as the bunching was increased. The relative amplitudes of the two peaks was very sensitive to tuning parameters. This, coupled with a lack of information about the transverse profile of the bunch, complicated the analysis and made a simple width assignment difficult. Measurements were also made with an MCP timing grid for comparison. The general shape and trend of the two data sets were similar; however, the widths measured by the timing grid were about 30-50% smaller.
poster icon Poster WEPG54 [2.160 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG54  
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WEPG55 Synchronization of ps Electron Bunches and fs Laser Pulses Using a Plasmonics-Enhanced Large-Area Photoconductive Detector 774
  • E.J. Curry, M. Jarrahi, P. Musumeci, N.T. Yardimci
    UCLA, Los Angeles, California, USA
  • B.T. Jacobson
    RadiaBeam, Santa Monica, California, USA
  Temporal synchronization between short relativistic electron bunches and laser pulses at the ps and sub-ps level is required for accelerator applications like inverse Compton light sources. Photoconductive antennas with THz and sub-THz bandwidth which are gated by fs lasers provide this level of timing resolution. This paper describes the operating principals of the diagnostic along with bench-top experimental results with recently developed plasmonics-enhanced large-area devices. A vacuum chamber with robust electronic noise reduction has been designed for upcoming beam-based experiments.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG55  
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WEPG56 Single-Shot THz Spectroscopy for the Characterization of Single-Bunch Bursting CSR 778
  • J. Raasch, M. Arndt, J. Hänisch, K.S. Ilin, K. Kuzmin, A.-S. Müller, A. Schmid, M. Siegel, J.L. Steinmann, S. Wuensch
    KIT, Karlsruhe, Germany
  • G. Cinque, M. Frogley
    DLS, Oxfordshire, United Kingdom
  • B. Holzapfel
    Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
  Funding: The work was supported by the BMBF (05K13VK4), the Helmholtz International Research School for Teratronics & the Karlsruhe School of Elementary Particle and Astroparticle Physics.
An integrated array of narrow-band high-Tc YBa2Cu3O7-x (YBCO) detectors embedded in broad-band readout was developed for the future use at synchrotron light sources as a single-shot terahertz (THz) spectrometer. The detection system consists of up to four thin-film YBCO nanobridges fed by planar double-slit antennas covering the frequency range from 140 GHz up to 1 THz. We present first results obtained at the ANKA storage ring and at Diamond Light Source during operation of two and four frequency-selective YBCO detectors, respectively.
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG56  
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WEPG57 Single-Shot THz Spectrometer for Bunch Length Measurements 782
  • S.V. Kutsaev, A.Y. Murokh, M. Ruelas, H.L. To
    RadiaBeam Systems, Santa Monica, California, USA
  • V. Goncharik
    Logicware Inc, New York, USA
  Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics, under contract DE-SC0013684
We present a new diagnostics instrument designed to measure bunch length in RF particle accelerators. Typically, scanning-type Michelson or Martin-Puplett interferometers are used to measure the coherent radiation from a short bunch. However, they require averaging over several shots over several minutes, thus being able to report only the average bunch length. We propose to measure the emitted coherent spectrum of a short bunch emission that contains the same spectral information as the bunch shape by means of single-shot spectrometry. In this paper we present design considerations, and first experimental results obtained at FACET for the instrument that allows shot-to-shot measurement of the emitted spectrum.
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG57  
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WEPG77 Sub-fs Resolution with the Enhanced Operation of the X-band Transverse Deflecting Cavity using an RF pulse Compression SLED Cavity 833
  • P. Krejcik, G.B. Bowden, S. Condamoor, Y. Ding, V.A. Dolgashev, J.P. Eichner, M.A. Franzi, A.A. Haase, J.R. Lewandowski, T.J. Maxwell, S.G. Tantawi, J.W. Wang, L. Xiao, C. Xu
    SLAC, Menlo Park, California, USA
  Funding: Work supported by DOE contract DE-AC03-76SF00515.
The successful operation of the x-band transverse deflecting cavity (XTCAV) installed downstream of the LCLS undulator has been further enhanced by the recent addition of an RF pulse compression "SLED" cavity that doubles the temporal resolving power of this powerful diagnostic system for measurement of the longitudinal profile of both the electron bunch and the x-ray FEL pulse. RF pulse compression has allowed us to use the existing SLAC X-band klystron with nominal output power of 50 MW and extend the RF pulse length by a factor 4 to give us 4 times the peak power after compression. A new, innovative SLED cavity was designed and built at SLAC to operate efficiently at X-band*. The elegant design uses a small spherical cavity combined with a polarizing mode coupler hybrid. We will report on the installation, commissioning and beam measurements demonstrating the sub-femtosecond resolution of the XTCAV system.
*J.W. Wang et al., "R&D of a Super-compact SLED System at SLAC", in Proc. 7th International Particle Accelerator Conference (IPAC'16), Busan, Korea, May 2016, paper MOOCA01, pp. 39-41.
poster icon Poster WEPG77 [20.909 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG77  
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THAL01 PALM Concepts and Considerations 848
  • P.N. Juranič, R. Abela, I. Gorgisyan, C.P. Hauri, R. Ischebeck, B. Monoszlai, L. Patthey, C. Pradervand, M. Radović, L. Rivkin, V. Schlott, A.G. Stepanov
    PSI, Villigen PSI, Switzerland
  • C.P. Hauri, L. Rivkin
    EPFL, Lausanne, Switzerland
  • R. Ivanov, P. Peier
    DESY, Hamburg, Germany
  • J. Liu
    XFEL. EU, Hamburg, Germany
  • K. Ogawa, T. Togashi, M. Yabashi
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  • S. Owada
    JASRI/RIKEN, Hyogo, Japan
  The Photon Arrival and Length Monitor (PALM), a THz streak camera device developed by PSI for non-destructive hard x-ray measurements of photon pulse length and arrival time versus a pump laser*, was brought to the SACLA XFEL** in Japan in a cross-calibration temporal diagnostics campaign after an initial experiment where only the PALM was being used***. The device was used with 9 keV pink beam and a 9.0 and 8.8 keV two-color mode, successfully measuring the arrival time and pulse lengths for several different FEL operating conditions. The device has shown itself to be very robust and transparent to the FEL beam, with temporal characterization accuracies of 15 fs or better. SwissFEL will employ two such devices at the end stations for use by both operators and experimenters to improve the operation of the FEL and to better interpret experimental data. This report presents the PALM and its uses and capabilities, and discusses the results from the SACLA cross-calibration experiments.
* P. N. Juranic et. al, Journal of Instrumentation (2014) 9.
** T. Ishikawa et. al., Nature Photonics (2012) 6(8).
*** P. N. Juranic et. al., Optics Express (2014) 22.
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-THAL01  
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