Time Resolved Diagnostics and Synchronization
Paper Title Page
MOCLA01 Microbunching Instability in Relativistic Electron Bunches: Direct Observations of the Microstructures Using Ultrafast YBCO Detectors 1
 
  • E. Roussel, S. Bielawski, C. Evain, C. Szwaj
    PhLAM/CERLA, Villeneuve d'Ascq, France
  • M. Adachi, M. Katoh, S.I. Kimura, T. Konomi
    UVSOR, Okazaki, Japan
  • M. Hofherr, K.S. Ilin, J. Raasch, A. Scheuring, M. Siegel, P. Thoma, S. Wuensch
    KIT, Karlsruhe, Germany
  • M. Hosaka, Y. Takashima, N. Yamamoto
    Nagoya University, Nagoya, Japan
  • H. Zen
    Kyoto University, Kyoto, Japan
 
  Relativistic electron bunches circulating in accelerators are subjected to a dynamical instability leading to microstructures at millimeter to centimeter scale. Although this is a well-known fact, direct experimental observations of the structures, or the field that they emit, remained up to now an open problem. Here, we report the direct, shot-by-shot, time-resolved recording of the shapes (including envelope and carrier) of the pulses of coherent synchrotron radiation that are emitted, and that are a 'signature' of the electron bunch microstructure. The experiments are performed on the UVSOR-III storage ring, using electrical field sensitive YBa2Cu3O7−x thin-film ultrafast detectors. The observed patterns are subjected to permanent drifts, that can be explained from a reasoning in phase space, using macroparticle simulations.
http://dx.doi.org/10.1103/PhysRevLett.113.094801
 
slides icon Slides MOCLA01 [37.740 MB]  
 
MOCLA02 Design of a Compact L-band Transverse Deflecting Cavity with Arbitrary Polarisations for the SACLA Injector 1
 
  • H. Maesaka, T. Asaka, T. Ohshima, Y. Otake, H. Tanaka
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  • S. Matsubara
    JASRI/SPring-8, Hyogo, Japan
 
  We are planning to install a transverse deflecting cavity (TCAV) in the injector of the X-ray free electron laser (XFEL) facility, SACLA [*], in order to measure longitudinal bunch profiles after a velocity bunching process. This is because the longitudinal bunch profile in the injector is critically important for reproducing the XFEL performance [**]. The TCAV will be installed at the end of the velocity bunching section, where the bunch length ranges from 10 ps to several 100 ps, the kinetic energy of the beam is approximately 1 MeV, and the transverse beam motion is rotated by solenoid lenses. Considering these conditions, we designed a compact L-band (1428 MHz) TM110-mode pillbox-shape TCAV (~300 mm-diameter and ~100 mm-long) with two input ports intersecting at a right angle. One of the advantages of this TCAV is that the polarisation of a deflecting rf field can be freely chosen, e.g. linear or circular, by changing the amplitude and phase at each rf port. We can select the linear polarisation for linear streaking with an arbitrary direction, or the circular one for axially symmetric deflection to reduce transverse mixing due to a solenoid B-field, depending on the situation.
[*] T. Ishikawa, et al., Nature Photonics 6, 540-544 (2012).
[**] T. Asaka, et al., Proceedings of LINAC2012, 486-488, TUPB006, (2012).
 
slides icon Slides MOCLA02 [11.991 MB]  
 
MOCLA03
Fully Intensity and Timing Jitter Compensated Ultra-Fast Experiments at Accelerator-Driven Photonsources at High Repetition Rates  
 
  • S. Kovalev, M. Gensch, B.W. Green
    HZDR, Dresden, Germany
  • A.S. Fisher
    SLAC, Menlo Park, California, USA
  • T. Golz, N. Stojanovic
    DESY, Hamburg, Germany
  • T. Kampfrath
    FHI, Berlin, Germany
 
  Funding: European Union through project EUCALL
Timing jitter and power instabilities are crucial parameters which greatly reduce the applicability of accelerator driven light sources for time-resolved experiments. In this contribution we present a technique that allows achieving few 10 fs time-resolution in experiments operating at cw repetition rates of up to 100 kHz by employing high repetition rate data acquisition. The method employs a fs-level arrival time monitor based on electro-optic sampling* ** of residual pulses from a coherent diffraction radiator and a fast THz detector allowing for pulse to pulse detection of arrival time and pump intensity. The monitor can operate at high repetition rates cw (presently up to a few 100 kHz) and low electron bunch charges (sub pC). The prototype device has been tested at the quasi CW SRF accelerator (ELBE) by performing an ultra-fast THz driven magnetization dynamics experiment***. Our method has high potential to provide few fs level timing on next generation large scale X-ray photon sources based on high repetition rate electron accelerators such as LCLSII. A demonstrator aiming at operation up to 4.7 MHz is under development for the European X-FEL.
* Z. Jiang, X. C. Zhang, IEEE Journal of Quantum Electronics, 36, 1214, 2000
** I. Wilke et al., Phys. Rev. Lett., 88, 124801, 2002.
*** S. Kovalev et. al., under review (2015).
 
 
MOPB001 Development of a Beam Pulse Monitor for the Heavy Ion Accelerator Facility 1
 
  • D. Tsifakis, P. Linardakis, N.R. Lobanov
    Research School of Physics and Engineering, Australian National University, Canberra, Australian Capitol Territory, Australia
 
  The ANU Heavy Ion Accelerator Facility (HIAF) comprises a 15 MV electrostatic accelerator (NEC 14UD) followed by a superconducting LINAC booster. The pulsing system consists of a low energy single gap gridded buncher and two high energy choppers. Buncher and choppers need to be set in phase and amplitude for maximum efficiency. The LINAC encompasses twelve lead tin-plated Split Loop Resonators (SLR). Each SLR, as well as the superbuncher and time energy lens, needs to be individually tuned in phase and amplitude for correct operation. The HIAF pulsing system is based on a few techniques. The first one utilises a U-bend at the end of the LINAC. One special wide Beam Profile Monitor (BPM) is installed after the 90 degrees magnet. The technique allows to set up correct phase by observing the displacement of beam profile versus phase shift of the last phase locked resonator. The determination of beam pulse characteristics are based on X-ray detection produced by beam striking a Ta target. In this paper the HIAF set up for pulsed beam diagnostics with sub nanosecond time resolution is described. The system has demonstrated simplicity of operation and high reliability.  
poster icon Poster MOPB001 [3.526 MB]  
 
MOPB005
A Single-Shot High-Repetition Rate Electro-Optic Detection of Short Pulses Using the Photonic Time-Stretch Strategy  
 
  • E. Roussel, S. Bielawski
    PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
  • J.B. Brubach, L. Cassinari, M.-E. Couprie, M. Labat, L. Manceron, J.P. Ricaud, P. Roy, M.-A. Tordeux
    SOLEIL, Gif-sur-Yvette, France
  • C. Evain, C. Szwaj
    PhLAM/CERLA, Villeneuve d'Ascq, France
  • M. Le Parquier
    CERLA, Villeneuve d'Ascq, France
 
  In accelerator-based light sources, there is a growing need for high repetition rate, single-shot, characterization of electron bunch shapes and THz pulses. At moderate repetition rate, an efficient strategy consists in encoding the ultrafast information onto a laser pulse, which is subsequently analysed (electro-optic sampling). However, these methods usually require cameras as the final detector, which represents a bottleneck in the quest for high-repetition rates. A promising candidate for breaking this « high repetition rate barrier » is the so-called photonic time-stretch technique. In this presentation, we present the first results obtained with time-stretch in the accelerator context: Electro-optic sampling of successive terahertz bursts of coherent synchrotron radiation at SOLEIL*, with 88 MHz acquisition rates (and picosecond resolution). In practice, the time-stretch is potentially realizable as a relatively simple upgrade of existing setups (provided it is possible to imprint the ultrafast signal on chirped laser pulses). Finally we also present a performance analysis, including a comparative study of standard and time-stretched electro-optic sampling setups.
* "Observing microscopic structures of a relativistic object using a time-stretch strategy," E. Roussel et al., Scientific Reports 5, 10330 (2015).
 
poster icon Poster MOPB005 [3.282 MB]  
 
MOPB006
Electro-Optical Measurements of the Longitudinal Bunch Profile in the Near-Field on a Turn-by-Turn Basis at the Anka Storage Ring  
 
  • E. Roussel, S. Bielawski
    PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
  • A. Borysenko, N. Hiller, A.-S. Müller, P. Schönfeldt, J.L. Steinmann
    KIT, Karlsruhe, Germany
  • C. Evain, C. Szwaj
    PhLAM/CERLA, Villeneuve d'Ascq, France
 
  Funding: This work is partially funded by the German Federal Ministry of Education and Research (BMBF) under contract numbers: 05K10VKC, 05K13VKA.
ANKA is the first storage ring worldwide with a near-field single-shot electro-optical bunch profile monitor. Previously, the method of electro-optical spectral decoding (EOSD) was employed to record single-shot longitudinal bunch profiles. The readout rate of the required spectrometer detector system limited the acquisition rate to a few Hz and thus did not allow us to study the evolution of the longitudinal bunch shape on a turn-by-turn basis. The setup at ANKA was combined with the novel method of photonic time-stretch* for which the modulated laser pulse is not detected in the spectral domain, but stretched to a few nanoseconds by a long fiber and, subsequently, detected in the time domain. This method allows the sampling of the longitudinal bunch profile on a turn-by-turn basis for several milliseconds, uninterrupted. Here, we present first results obtained with the photonic time-stretch method in the near-field at the ANKA storage ring.
* "Observing microscopic structures of a relativistic object using a
time-stretch strategy," E. Roussel et al, Scientific Reports 5, 10330
(2015).
 
 
MOPB009 Jitter Analysis at CW Repetition Rate With Large Spectral Range and High Resolution. 1
 
  • M. Kuntzsch, M. Gensch, U. Lehnert, P. Michel, R. Schurig, J. Teichert
    HZDR, Dresden, Germany
 
  At the superconducting CW accelerator ELBE electron bunch diagnostics has been installed recently, enabling the investigation of bunch arrival-time jitter and electron energy fluctuations for varying bunch compression states. Using these diagnostic systems, a comprehensive investigation has been performed that reveals the influence of the bunch compression to spectral noise components up to a frequency of 100 kHz (i.e. 200 kHz bunch repetition rate). The transformation of arrival-time jitter into energy jitter and vice versa can be observed. The perfomances of a DC thermionic and a SRF photoinjector at the CW- SRF Linac ELBE are compared and an interpretation for different noise components is presented.  
 
MOPB011
Trigger Generator for the Superconducting Linear Accelerator ELBE  
 
  • R. Steinbrück, M. Justus, M. Kuntzsch
    HZDR, Dresden, Germany
  • T. Bergmann
    BME, Murnau, Germany
  • A. Kessler
    HIJ, Jena, Germany
 
  Funding: none
The Center for High-Power Radiation Sources ELBE at HZDR in Germany runs a superconducting linear electron accelerator for research applications. A recent machine upgrade enabled new time resolved experiments and made a replacement of the current trigger system necessary. The requirements focused on centralisation, trigger quality, and versatile trigger pattern generation. To address these needs digital delay generators developed by Bergmann Messgeräte Entwicklung have been evaluated. Each of the FPGA-based PCI boards has 6 independent trigger channels with a resolution of 25 ps. PCI modules can be connected by a dedicated trigger bus to ensure extensibility. The boards are installed in an industrial Windows 7 PC. Trigger generation runs stand-alone in an FPGA making it independent of operating system timing and ensuring stable phase relation between individual channels. FPGA control is possible via C and LabVIEW APIs. The ELBE control system is built with Siemens PLCs and WinCC HMI. A LabVIEW application will offer a GUI for local and remote control via OPC. The contribution will show the layout of the trigger generation system and the status of software development activities.
 
 
MOPB017 Development of FPBA-Based TDC With Wide Dynamic Range for Monitoring the Trigger Timing Distribution System at the KEKB Injector Linac 1
 
  • T. Suwada, K. Furukawa, F. Miyahara
    KEK, Ibaraki, Japan
 
  A new field-programmable gate array (FPGA)-based time-to-digital converter (TDC) with a wide dynamic range greater than 20 ms has been developed to monitor the timing of various pulsed devices in the trigger timing distribution system of the KEKB injector linac. The pulsed devices are driven by feeding regular as well as any irregular (or event-based) timing pulses. For monitoring the timing as precisely as possible, a 16-ch FPGA-based TDC has been developed on a Xilinx Spartan-6 FPGA equipped on VME board with a time resolution of 1 ns. The resolution was achieved by applying a multisampling technique, and the accuracies were 2.6 ns (rms) and less than 1 ns (rms) within the dynamic ranges of 20 ms and 7.5 ms, respectively. The various nonlinear effects were improved by implementing a high-precision external clock with a built-in temperature-compensated crystal oscillator.  
poster icon Poster MOPB017 [3.161 MB]  
 
MOPB034 CW Laser Based Phase Reference Distribution for Particle Accelerators 1
 
  • S. Jabłoński
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
  • H. Schlarb, C. Sydlo
    DESY, Hamburg, Germany
 
  We present a cost-effective solution for the synchronization of RF signal sources separated by tens of kilometers with the femtosecond accuracy. For the synchronization a phase reference distribution system (PRDS) is developed, which is comprised of a CW optical transmitter connected via single mode fiber-optic links to remote receivers. This technique enables to use only one transmitter for multiple receivers and removes the necessity of active stabilization units (e.g. piezo-driven fiber stretchers or laser wavelength tuning), which reduces considerably the system cost. The concept of the new RF reference distribution, parameters of crucial components, phase drift detection and correction techniques are introduced, which lead to low noise and long-term stable PRDS operation. Detrimental effects of various linear and nonlinear fiber impairments are discussed. One of the most important elements is the phase detector, which is based on a direct RF-sampling ADC and it features a femtosecond measurement precision over 2pi phase change. Finally, the long-term performance of the designed PRDS is shown, which was evaluated with a 500-m single-mode fiber and an RF signal of 1.3 GHz.  
 
MOPB037 Development of High Precision Capacitive Beam Phase Probe for KHIMA Project 1
 
  • J.G. Hwang, S.Y. Noh
    KIRAMS/KHIMA, Seoul, Republic of Korea
  • P. Forck
    GSI, Darmstadt, Germany
  • T.K. Yang
    KIRAMS, Seoul, Republic of Korea
 
  In the medium energy beam transport (MEBT) line of KHIMA project, a high precision beam phase probe monitor is required for a precise tuning of RF phase and amplitude of RFQ and IH-DTL. It is also used for measuring a kinetic energy of ion beam by time-of-flight (TOF) method using two phase probes. In this paper, we show the electromagnetic design of the high precision phase probe to satisfy the phase resolution of 1 deg (@ 200 MHz), the test result with a wire test bench to estimate a signal strength and phase accuracy, the design of the 0.2 ~ 2.0 GHz broad-band electronics for amplifying the signal strength, and the results of beam energy and RF frequency measurement using a proton beam from the cyclotron in KIRAMS.  
 
MOPB048 Design Concept for a THz Driven Streak Camera With Ultra High Resolution 1
 
  • M.M. Dehler, F. Frei, R. Ischebeck, V. Schlott
    PSI, Villigen PSI, Switzerland
  • J. Fabianska, T. Feurer, M. Hayati
    Universität Bern, Institute of Applied Physics, Bern, Switzerland
 
  The resolution of streak camera systems strongly depends on the slew rate of the deflecting element, being proportional to the amplitude and the frequency of the deflector. An attractive approach to reach femto and even sub-femtosecond resolution are THz driven electron streak cameras, which have been only recently proposed. Here, the ultra fast streaking field is generated by exciting a suitable resonant THz antenna, e.g. a split ring resonator with an intense THz pulse. With today's THz sources streak field amplitudes in excess of 1 GV/m are within reach. Here, we present the concept for a proof of principle system. The THz pulse will be generated by rectifying the pulse from an existing 800 nm laser system in a suitable crystal as LiNbO3. For the source of the electron beam to be streaked, we are exploring two options, first a DC driven photo gun with electron energies between 10 and 100 keV, and second an RF photo gun yielding a relativistic 6.5 MeV beam. We describe the setup of the system for both cases and present simulations of the beam dynamics.  
 
MOPB052
Plasma Monitor for Ultra-Short SwissFEL Electron Bunch Peak Current Measurement  
 
  • R. Tarkeshian, R. Ischebeck, V. Schlott
    PSI, Villigen PSI, Switzerland
 
  The peak current is a crucial factor in the lasing process of free electron laser (FEL). In order to obtain the high peak current, and short gain-length the electron bunch needs to be compressed. New techniques for resolving few fs or even sub-fs SwissFEL bunches are required. The electric field for the SwissFEL compressed bunch (< 20fs rms at 200 pC) is in GV/m level. Therefore it is proposed here to use SwissFEL bunches to tunnel-ionize neutral gas. The tunneling effect has exponential dependence on the electric field and bunch peak current. Therefore by characterizing the plasma emission, ion or electron wakes the bunch peak-current can be inferred. The field ionization effects can be characterized by the electron beam energy loss and a transverse size measurement upstream of the plasma cell. The PIC simulation package VSim* is used to carry out simulations of the SwissFEL beam propagating through the gas. First simulation results compared with theoretical prediction and analytical modeling as well as the proposed experimental setup will be presented.
*TECH-X, VSIM 7.2, http://www.txcorp.com/home/vsim/
 
 
MOPB063 First Experimental Results with the CLIC Drive Beam Phase Feedforward Prototype at the CLIC Test Facility CTF3 1
 
  • G.B. Christian, P. Burrows, C. Perry, J. Roberts
    JAI, Oxford, United Kingdom
  • A. Andersson, R. Corsini, R. Corsini, J. Roberts, J. Roberts, P.K. Skowroński, P.K. Skowroński
    CERN, Geneva, Switzerland
  • P. Burrows, C. Perry
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
  • A. Ghigo, A. Ghigo, F. Marcellini, F. Marcellini
    INFN/LNF, Frascati (Roma), Italy
 
  Funding: Work supported by the European Commission under the FP7 Research Infrastructures project Eu-CARD, grant agreement no. 227579
The two-beam acceleration scheme envisaged for CLIC will require a high degree of phase stability between two beams at the drive beam decelerator sections, to allow efficient acceleration of the main beam. There will be up to 48 such decelerator sections for the full 3 TeV design, and each decelerator section will be instrumented with a feed-forward system to correct the drive beam phase to a precision of 0.2 degrees at 12 GHz relative to the main beam, using a kicker system around a four-bend chicane. A prototype system has been developed and tested at the CLIC Test Facility (CTF3) complex, where the beam phase is measured upstream of the combiner ring and corrected with two kickers in a dog-leg chicane just upstream of the CLEX facility, where the resulting phase change is measured. This prototype is designed to demonstrate correction of a portion of the CTF3 bunch train to the level required for CLIC, with a bandwidth of greater than 30 MHz, and within a latency constraint of 380 ns as set by the beam time-of-flight through the combiner ring complex. A description of the hardware will be given and initial results from the first phase of the experiment will be presented.
 
poster icon Poster MOPB063 [1.783 MB]  
 
MOPB066 Streak Camera PSF Optimisation and Dual Sweep Calibration for Sub-ps Bunch Length Measurement 1
 
  • L.M. Bobb, A.F.D. Morgan, G. Rehm
    DLS, Oxfordshire, United Kingdom
 
  Streak cameras are commonly used for bunch length measurement. In normal beam modes, bunch lengths are on the order of 10 ps. For the study of microbunch instabilities, a low alpha single bunch mode is implemented with bunch lengths approaching 1 ps and beam current in the tens of microamps. In order to reliably measure such a short bunch at low beam currents, the input optics for the streak camera must be optimised for sufficient incident light intensity and high resolution in both sweep directions. This is achieved through the use of reflective input optics in which a pinhole is imaged to provide a small circular Point Spread Function. Furthermore to precisely measure the bunch length, the calibration of the dual sweep must be known. Here we describe a calibration method using electrical delays to incorporate calibration information within streak camera images.  
poster icon Poster MOPB066 [0.739 MB]  
 
MOPB074 Reference Signal Distribution for Beam Position and Phase Monitors at LANSCE 1
 
  • R.C. McCrady, H.A. Watkins
    LANL, Los Alamos, New Mexico, USA
 
  Funding: This work is supported by the United States Department of Energy under contract DE-AC52-06NA2596.
The new beam position and phase monitors at LANSCE measure the phase of the beam relative to a reference signal from the master reference oscillator. The distribution of the reference signal along the 800 m long linac is subject to thermal effects, and phase drifts of the reference signal are observed to be greater than 15 degrees. We are investigating stabilisation schemes, one of which involves distributing two RF signals of different frequencies. By observing the phase difference between the two signals, the phase drift of the reference signal can be deduced. Initial tests indicate that the reference can be stabilised to within 0.5 degrees using this scheme. In this paper we will present the principles of operation of this stabilisation scheme and results from tests of the system.
 
 
MOPB076
Implementation of Phase Cavity Algorithm for Beam Arrival Time Monitoring System for LCLS  
 
  • K.H. Kim, J.C. Frisch, B.L. Hill, S.R. Smith, E. Williams
    SLAC, Menlo Park, California, USA
 
  Funding: US DOE
The phase cavity system is an essential part of the femtosecond timing system for the Linac Coherent Light Source (LCLS) at the SLAC National Accelerator Laboratory. Electrons exiting the LCLS undulator excite a phase cavity which measures the electron beam time relative to a phase reference line from the accelerator. Beam phase measured by the cavity is very sensitive to the cavity resonant frequency. We compensate for this effect by measuring cavity frequency on each beam pulse and correct the measured phase using calibration data, giving more accurate phase for the reference line feedback. We implement major numerical calculations and slow feedback in a processor separate from the phase cavity real-time system to avoid real-time performance dragging for shot to shot phase measurements. The new algorithm also reduces down the computational complexity of the real-time system to O(N) from O(N log N) comparing to the current implementation. The reliability of algorithm and exception handling for the communication between those systems is important. We describe implementation details and improvements in this poster.
 
poster icon Poster MOPB076 [1.626 MB]  
 
MOPB080
Design and Commissioning of in-Vacuum Martin-Puplett Interferometer at Elbe Facility  
 
  • P.E. Evtushenko
    JLab, Newport News, Virginia, USA
  • J. Hauser, R. Schurig
    HZDR, Dresden, Germany
 
  ELBE is an SRF LINAC based multipurpose user facility delivering electron beam with average current of up to 1 mA and beam energy of up to 40 MeV. During routine operation with thermionic triode gun the accelerator can operate with the RMS bunch length in the range from a few hundred fs to a few ps. The latest addition to the facility is a beam line for THz radiation generation. By design the beam line needs to operate with the RMS bunch length as short as 200 fs. In-vacuum Martin-Puplett interferometer (MPI) for bunch length measurements in the aforementioned bunch length range was designed, constructed, and commissioned with beam. In this contribution we describe the instrument and its design considerations. We also present bunch length measurements obtained during commissioning of the MPI with beam. RSM bunch length in the range from sub-600 fs to ~2 ps was measured. In this range we observe that the MPI can easily measure bunch length change of about 25 fs. At this point the measured bunch length range is attributed to the beam dynamics limitations rather than to the instrument itself. The instrument systematics, alignment, and further commissioning plans are discussed as well.  
 
MOPB081 Sub-Picosecond Shot-to-Shot Electron Beam and Laser Timing Using a Photoconductive THz Antenna 1
 
  • E.J. Curry, P. Musumeci
    UCLA, Los Angeles, California, USA
  • B.T. Jacobson, A.Y. Murokh
    RadiaBeam, Santa Monica, California, USA
 
  Temporal synchronization systems, which measure electron beam time of arrival with respect to a laser pulse, are critical for operation of advanced laser-driven accelerators and light sources. State-of-the-art synchronization tools, relying on electronic e-beam response and photodetector laser response are limited to few GHz bandwidths in most practical configurations. This paper presents a temporal diagnostic instrumentation based upon a photoconductive THz antenna, which could offer an inexpensive and user friendly method to provide shot-to-shot relative time of arrival information with sub-picosecond accuracy. We describe the overall instrument design and proof-of-concept prototype results at the UCLA PEGASUS facility.  
 
MOPB082 NSLS2 Fill Pattern Monitor and Control 1
 
  • W.X. Cheng, B. Bacha, Y. Hu, O. Singh, G.M. Wang
    BNL, Upton, Long Island, New York, USA
 
  NSLS2 storage ring has harmonic number of 1320. Possible fill patterns include multi bunch train(s) followed by ion cleaning gap(s), hybrid fill with single bunch in the ion gap. Storage ring filling pattern can be measured using button BPM sum signal together with high speed digitizer or oscilloscope. Button BPM sum signal typically has dynamic range of 10-2 to 10-3. Nonlinearity of BPM sum signal dependence on beam position has been characterized. In preparation for high dynamic single bunch current measurement, a filling pattern monitor system using synchrotron radiation is under development. Besides, the storage ring filling pattern can be controlled using the bunch cleaning function integrated in the bunch-by-bunch feedback system. Results of these two filling pattern monitors and bunch cleaning will be presented.  
 
MOPB083 Longitudinal Bunch Profile Measurement at NSLS2 Storage Ring 1
 
  • W.X. Cheng, B. Bacha, A. Blednykh, Y. Li, O. Singh
    BNL, Upton, Long Island, New York, USA
 
  Longitudinal bunch profile has been measured at NSLS2 storage ring using streak camera. From the measured profile, bunch lengthening and synchronous phase information can be derived to study the single bunch collective effect. Single bunch lengthening effect has been measured for bare lattice and for other lattices with different insertion devices. The streak camera can also be setup for other beam physics studies, for example to measure the injection beam dynamics and fast ion effects. Y-z imaging was measured using cylindrical lenses. Single bunch y-z profile was measured at threshold current.  
 
TUALA01 Beam Arrival Time Monitors 1
 
  • J.C. Frisch
    SLAC, Menlo Park, California, USA
 
  Funding: Work supported by the US Department of Energy contract DE-AC02-76SF00515
This is an overview of beam arrival time measurement techniques for FELs and other accelerators requiring femtosecond timing. This talk will present the trade-offs between the various techniques used at different facilities.
 
slides icon Slides TUALA01 [5.928 MB]