Keyword: electron
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MOCB04 Vertical Emittance Measurements using a Vertical Undulator undulator, emittance, photon, brilliance 20
 
  • K.P. Wootton, R.P. Rassool, G. Taylor
    The University of Melbourne, Melbourne, Australia
  • M.J. Boland, B.C.C. Cowie, R.T. Dowd, Y.E. Tan
    ASCo, Clayton, Victoria, Australia
  • Y. Papaphilippou
    CERN, Geneva, Switzerland
  
  With vertical dimensions of several microns, direct measurement of beam size is approaching diffraction limits of visible light and hard x-ray emittance diagnostics. We report on the development of a new vertical electron beam size measurement and monitoring technique which utilizes a vertical undulator. An APPLE-II type undulator was phased to produce a horizontal magnetic field, deflecting the electron beam in the vertical plane. The measured ratios of undulator spectral peak heights are evaluated by fitting to simulations of the apparatus. Vertical electron beam emittances of several picometres have been observed at the Australian Synchrotron storage ring. With this apparatus immediately available at most existing electron and positron storage rings, we find this to be an appropriate and novel vertical emittance diagnostic.  
slides icon Slides MOCB04 [3.449 MB]  
 
MOCC01 UV/X-ray Diffraction Radiation for Non-intercepting Micron-scale Beam Size Measurement target, radiation, experiment, background 24
 
  • L.M. Bobb, N. Chritin, T. Lefèvre
    CERN, Geneva, Switzerland
  • M.G. Billing
    CLASSE, Ithaca, New York, USA
  • L.M. Bobb, V. Karataev
    JAI, Egham, Surrey, United Kingdom
  
  Diffraction Radiation (DR) is produced when a relativistic charged particle moves in the vicinity of a medium. The electric field of the charged particle polarizes the target atoms which then oscillate, emitting radiation with a very broad spectrum. The spatial-spectral properties of DR are sensitive to a range of electron beam parameters. Furthermore, the energy loss due to DR is so small that the electron beam parameters are unchanged. Therefore DR can be used to develop non-invasive diagnostic tools. The aim of this project is to measure the transverse (vertical) beam size using incoherent DR. To achieve the micron-scale resolution required by CLIC, DR in the UV and X-ray spectral-range must be investigated. During the next few years, experimental validation of such a scheme will be conducted on the CesrTA at Cornell University, USA. Here we present the current status of the experiment preparation.  
slides icon Slides MOCC01 [3.064 MB]  
 
MOCC03 The First Electron Bunch Measurement by means of DAST Organic EO Crystals laser, FEL, real-time, operation 29
 
  • Y. Okayasu, S. Matsubara, T. Togashi
    JASRI/SPring-8, Hyogo-ken, Japan
  • M. Aoyama
    JAEA/Kansai, Kyoto, Japan
  • A. Iwasaki, S. Owada
    The University of Tokyo, Tokyo, Japan
  • T. Matsukawa
    RIKEN ASI, Sendai, Miyagi, Japan
  • H. Minamide
    RIKEN Advanced Science Insititute, Sendai, Miyagi, Japan
  • K. Ogawa, T. Sato, H. Tomizawa
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  • E. Takahashi
    RIKEN, Saitama, Japan
  
  Pilot user experiments via the seeded FEL have been demonstrated at the Prototype Test Accelerator (VUV-FEL), SPring-8 from July, 2012. A precise measurement of the electron bunch charge distribution (BCD) is crucial key to keep spatial and temporal overlaps between high-order harmonic (HH) laser pulses and electron bunches. R&D of the 3D-BCD monitor with a single-shot detection has been extensively promoted at SPring-8. The monitor adopts a spectral decoding based Electro-Optic (EO) sampling technique that is non-destructive and enables real-time reconstruction of the 3D-BCD with a temporal resolution of 30- to 40-fs (FWHM). So far, such EO sampling based BCD monitors have been developed by utilizing inorganic EO crystals such as ZnTe and their temporal resolutions are limited to ~130 fs (FWHM). As a part of this project, the first BCD measurement with an organic EO crystal DAST has been successfully demonstrated at the facility. Signal intensities, temporal resolutions and radiation related issues via both ZnTe and DAST are discussed.  
slides icon Slides MOCC03 [3.912 MB]  
 
MOCC04 Improvement of Screen Monitor with Suppression of Coherent-OTR Effect for SACLA target, emittance, operation, radiation 34
 
  • S. Matsubara, Y. Otake
    RIKEN/SPring-8, Hyogo, Japan
  • S.I. Inoue
    SES, Hyogo-pref., Japan
  • H. Maesaka
    RIKEN Spring-8 Harima, Hyogo, Japan
  
  The construction of SACLA (SPring-8 Angstrom Compact free electron LAser) was already completed and it is under operation. A screen monitor (SCM) system has been developed and was installed in order to obtain a direct image of a transverse beam profile with a spatial resolution of about 10 um, which is required to investigate electron-beam properties, such as a beam emittance. The SCM originally has a stainless steel target as a OTR radiator or a Ce:YAG crystal as a scintillation target. At the beginning of the SACLA operation, strong coherent OTR (COTR), which made an incorrect beam profile, was observed after bunch compressors. In order to suppress the COTR on the SCM, the stainless steel target was replaced to the Ce:YAG scintillation target. Since the COTR was still generated from the Ce:YAG target, a spatial mask was employed. The mask was mounted on the center of the optical line of the SCM, because the COTR light is emitted forward within ~1/γ radian, while the scintillation light has not angular dependence. Clear beam profiles with a diameter of a few tens of micro-meter are observed by means of the SCMs with this simple improvement.  
slides icon Slides MOCC04 [1.618 MB]  
 
MOIC02 Electron Beam Diagnostic System for the Japanese XFEL, SACLA undulator, emittance, cavity, radiation 38
 
  • H. Maesaka, H. Ego, C. Kondo, T. Ohshima, Y. Otake, H. Tomizawa
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  • S. Matsubara, T. Matsumoto, K. Yanagida
    JASRI/SPring-8, Hyogo, Japan
  
  An x-ray free-electron laser (XFEL) based on self-amplified spontaneous emission (SASE) requires a highly brilliant electron beam. The Japanese XFEL facility, SACLA, requires a normalized emittance less than 1 mm mrad and a peak current more than 3 kA. To achieve this high peak current, 1 A beam with 1 ns duration from a thermionic electron gun is compressed down to 30 fs by means of a multi-stage bunch compressor system. Therefore, the beam diagnostic system for SACLA was designed for the measurements of the emittance and bunch length at each compression stage. We developed a high-resolution transverse profile monitor and a temporal bunch structure measurement system with a C-band rf deflector cavity etc. In addition, precise overlapping between an electron beam and radiated x-rays in the undulator section is necessary to ensure the XFEL interaction. Therefore, we employed a C-band sub-micron resolution RF-BPM to fulfill the demanded accuracy of 4 um. The beam diagnostic system surely contributed to the first x-ray lasing at a wavelength of 1.2 Angstrom. We present a design strategy of the whole beam diagnostic system and the achieved performance for each monitor.  
slides icon Slides MOIC02 [7.861 MB]  
 
MOPA02 270 degree Electron Beam Bending System using Two Sector Magnets for Therapy Application target, linac, dipole, simulation 50
 
  • S.D. Dhole, S. Akhter, V.N. Bhoraskar, B.J. Patil
    University of Pune, Pune, India
  • S.T. Chavan, R. Krishnan, S.N. Pethe
    SAMEER, Mumbai, India
  
  The 270 degree doubly achromatic beam bending magnet system using two sector magnets has been designed mainly for treating cancer and skin diseases. The main requirements of the design of two magnet system is to focus an electron beam having a spot size less than 3 mm X 3 mm, energy spread within 3% and divergence angle <= 3 mrad at the target. To achieve these parameters the simulation was carried out using Lorentz-3EM software. The beam spot, divergence angle and energy spread were observed with respect to the variation in angles of sector magnets and drift distance. From the simulated results, it has been optimized that the first and second magnet has an angle 195 degree and 75 degree and the drift distance 64 mm. It is also observed that at the 1396, 2878 and 4677 A-turn, the optimized design produces 3324, 6221 and 9317 Gauss of magnetic field at median plane require to bend 6, 12 and 18 MeV electron respectively. The output parameters of the optimized design are energy spread 3 %, divergence angle ~ 2.8 mrad and spot size 2.6 mm.  
 
MOPA04 An Electron Beam Profile Monitor for the Race-track Microtron controls, microtron, experiment, operation 54
 
  • S.D. Dhole, V.N. Bhoraskar, B.J. Patil, N.S. Shinde
    University of Pune, Pune, India
  
  In electron irradiation experiments on materials such as semiconductors, solar cells etc., an uniformity and the charge distribution in the electron beam is very important. Therefore, an electron beam current monitor and its electronic system have been designed and built to measure the distribution of a beam current either in the horizontal or vertical direction along with the beam dimensions. To obtain X-Y beam profile, a special type of Faraday Cup was designed which mainly consists of charge collecting electrodes made up of thin copper strips. Each strip having dimensions 0.5 mm wide, 4 mm thick and 20 mm long were fixed parallel to each other and separation between them was ~ 0.5 mm. This multi electrode Faraday was mounted at the extraction port of the Race Track Microtron, where 1 MeV electron beam allowed to fall on it. The beam characterization in the form of current and uniformity were measured. The current from each strip were measured using an electronic circuit developed based on the multiplexing principle. The uniformity of the beam can be measured with an accuracy of 10%. The minimum and maximum dimensions which can be measured are 3 mm and 15 mm respectively.  
 
MOPA13 Real-time Calculation of Scale Factors of X-ray Beam Position Monitors during User Operation photon, polarization, factory, insertion 79
 
  • C. Bloomer, G. Rehm
    Diamond, Oxfordshire, United Kingdom
  
  Photoemission based X-ray Beam Position Monitors (XBPMs) are widely used at 3rd generation light sources to both monitor and stabilise the photon beam to sub-micron precision. Traditionally, finding the geometric scale factors requires either systematic stepper motor movements of the XBPM or well controlled electron beam displacements to measure the response of the XBPM. For each Insertion Device gap it is required to repeat this in order to build up a complete set of scale factors covering all possible operating conditions. Elliptically Polarising Undulators further complicate matters by having multiple operating modes which would require multi dimensional lookup tables. Presented in this paper is a method for retrieving the geometric scale factors of an XBPM in real time by making use of the intrinsic small random movements of the electron beam and finding the correlation in synchronous measurements from Electron BPMs and XBPMs at kHz sample rates.  
 
MOPA17 Modular Logarithmic Amplifier Beam Position Monitor Readout System at the University of Hawai'i GUI, FEL, detector, laser 90
 
  • B.T. Jacobson, M.R. Hadmack, J. Madey, P. Niknejadi
    University of Hawaii, Honolulu, HI, USA
  
  High brightness electron beams for inverse Compton backscatter photon sources driven by thermionic microwave guns require real-time position measurements in order to achieve the spatial and temporal coincidence necessary to ensure statistically measurable signals. True logarithmic amplifiers are more adequately suited to signal comparison than are σ-delta methods. A low-cost, modular and scalable readout and data acquisition system for strip-line beam position monitors utilizing the AD640 log-amp is being developed at University of Hawai'i MkV Linear Accelerator and Free Electron Laser Lab. Initial measurements and prototyping of the hardware is complete with commissioning and deployment of the system currently ongoing. We present the methodology and early results of this project.  
 
MOPA20 Development of 3D EO-Sampling System for the Ultimate Temporal Resolution FEL, laser, timing, feedback 98
 
  • K. Ogawa, H. Tomizawa
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  • S. Matsubara, Y. Okayasu
    JASRI/SPring-8, Hyogo, Japan
  
  We have been developing three dimensional bunch charge distribution (3D-BCD) monitor for FEL seeded with high-order harmonic (HH) pulse. 3D-BCD is based on EO-sampling technique with multiple EO crystal detectors in the manner of spectral decoding. Using this 3D-EO sampling technique, the positioning and timing of electron bunch is obtained in real-time with non-destructive measurement. For obtaining the high temporal resolution, an octave broadband probe laser with linear chirp rate of 1 fs/nm is required. We are developing an EO-probe laser pulse with ~10 μJ pulse energy and the bandwidth over 300 nm (FWHM). For meet these bandwidth and pulse energy, this EO-probe pulse is using a supercontinuum generated by photonic crystal fiber (PCF) and amplified with optical parametric amplification (OPA). Especially, for amplification with maintaining octave bandwidth, non-collinear OPA (NOPA) using BBO crystal and a pump source with a wavelength of 450 nm are adopted. The EO-probe pulse energy of 10 μJ provides for high S/N ratio to each detector and the bandwidth of 300 nm with 300 fs pulse duration allows the measurement for the 30 fs electron bunch duration (FWHM).  
 
MOPA24 Photon Beam Position Monitor at SIAM Photon Source photon, undulator, insertion, insertion-device 104
 
  • P. Sudmuang, S. Boonsuya, S. Chaichuay, P. Klysubun, S. Krainara, H. Nakajima, S. Rugmai, N. Sumano, N. Suradet
    SLRI, Nakhon Ratchasima, Thailand
  
  Photon beam position monitors (PBPM) have been designed and installed in the beamline front-ends at Siam Photon Source (SPS). Up till now, these blade-type PBPMs have been successfully installed at three bending magnet and an insertion device (planar undulator) beamlines. Its performance has been tested and compared with that of the electron beam position monitor. The achieved resolution is found to be better than 3 μm. The obtained PBPM data proved to be extremely invaluable in the investigation of the sources of the observed beam positional fluctuation, and for compensation of the orbit perturbation caused by undulator gap change. In this paper, the details of the calibration procedure will be presented. Various factors affecting reading of the signal such as back scattering effect, choice of bias voltage, and temperature variation have been investigated and the results will be discussed herewith.  
 
MOPA28 Turn-by-turn BPM System using Coaxial Switches and ARM Microcontroller at UVSOR controls, injection, betatron, storage-ring 112
 
  • T. Toyoda
    IMS, Okazaki, Japan
  • K. Hayashi, M. Katoh
    UVSOR, Okazaki, Japan
  
  A major upgrade of the electron storage ring at UVSOR (Institute for Molecular Science, Japan) started from April 2012. To assist the commissioning procedure, we have developed a turn-by-turn Beam Position Monitor (BPM) system which consists of a signal switching circuit, a digital oscilloscope and software. The storage ring has 24 BPMs, each of which consists of four electrodes. By using the signal switching circuit, we can select one BPM from eight BPM's. The four signals from the BPM are sent to a digital oscilloscope and are recorded. In the switching circuit, coaxial switches of SPDT (Single Pole Dual Throw) and SP4T type are used. To control coaxial switches, we adopted 'mbed', the ARM microcontroller development kit. The 'mbed' stores the control applications configured in the HTML file and JavaScript library which can handle multiple I/O ports. It responds as a HTTP server and the control application runs on a Web browser. By clicking buttons with a mouse, we can control the I/O ports of 'mbed' through JavaScript library and accordingly can control coaxial switches. In the presentation, we will report the detail of the developed BPM system and its performance.  
 
MOPA43 RF Front end for High Bandwidth Bunch Arrival Time Monitors in Free-Electron Lasers at DESY pick-up, simulation, operation, laser 157
 
  • A. Penirschke, A. Angelovski, M. Hansli, R. Jakoby
    TU Darmstadt, Darmstadt, Germany
  • M. Bousonville, M.K. Czwalinna, H. Schlarb, C. Sydlo
    DESY, Hamburg, Germany
  • A. Kuhl
    Uni HH, Hamburg, Germany
  • S. Schnepp
    IFH, Zurich, Switzerland
  • T. Weiland
    TEMF, TU Darmstadt, Darmstadt, Germany
  
  Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors"
The Free-Electron Laser in Hamburg FLASH is equipped with Bunch Arrival-time Monitors (BAMs) that use an electro-optical detection scheme to modulate the intensity of the femtosecond laser pulse train with the pickup signals (*). The achieved resolution of the existing BAMs are less than 10 fs for bunch charges higher than 500 pC. For lower bunch charges the time resolution drops significantly. Increased demands for low bunch charge operation modes of 20 pC and less at FLASH II and the European X-ray Free-Electron Laser XFEL require an upgrade of the existing beam diagnostic equipment. High bandwidth BAMs with newly developed cone-shaped pickups (**) promise sub-10 fs time resolution for both, the high and low bunch charge operation mode. This paper addresses the RF signal path of the high bandwidth BAMs for FLASH II and XFEL. It comprises radiation resistant coaxial cables, combiners and limiters up to a frequency of 40 GHz from the pickup electrodes to the Electro-optical Mach-Zehnder type modulator (EOM). Detailed investigations of the signal path using measurements and simulations with AWR Microwave Office allows for a good prediction of the signal quality and shape at the EOM.
(*) F. Löhl et al., Phys. Rev. Lett. 104,144801 (2010)
(**) A. Angelovski et al. in Proceedings of the International Particle Accelerator Conference (IPAC2011), San Sebastian, Spain, 2011, p.1177
 		 
 
MOPA46 Realization and Measurements of Cone-shaped Pickups for Bunch Arrival-time Monitors for FLASH and XFEL pick-up, simulation, laser, free-electron-laser 165
 
  • A. Angelovski, M. Hansli, R. Jakoby, A. Penirschke
    TU Darmstadt, Darmstadt, Germany
  • M. Bousonville, M.K. Czwalinna, H. Schlarb, C. Sydlo
    DESY, Hamburg, Germany
  • A. Kuhl
    Uni HH, Hamburg, Germany
  • S. Schnepp
    IFH, Zurich, Switzerland
  • T. Weiland
    TEMF, TU Darmstadt, Darmstadt, Germany
  
  Funding: Funded by the Federal Ministry of Education and Research (BMBF): 05K10RDA "Weiterentwickung eines Ankunftszeitmonitors"
At the Free Electron Laser FLASH at DESY, the installed Bunch Arrival-time Monitors (BAMs) use an electro-optical detection scheme for arrival-time measurements. The achieved time resolution is in the sub-10 fs range for bunch charges higher than 500 pC. The extension of FLASH II and the European X-ray Free Electron Laser Project (XFEL) foresees a low charge operation mode with bunch charge of 20 pC or less. The time resolution of the BAMs significantly drops as the bunch charge reduces (*). By expanding the bandwidth of the pickups one can increase the time resolution at low charges. In this paper, we present the characterization results of the manufactured cone-shaped pickups introduced in (**) with a bandwidth up to 40 GHz. The pickups mounted in a vacuum body exhibit four-fold rotational symmetry with respect to the beam pipe. Due to different beam pipe apertures for FLASH and XFEL, two bodies are manufactured. The rf properties of the mounted pickups in case of open and sealed body as well as the pickups separately are measured and compared to the simulation results obtained by CST STUDIO SUITE®.
(*)M. K. Bock et al. in Proceedings of DIPAC 2011, Hamburg, Germany, 2011, p.365
(**)A. Angelovski et al. in Proceedings of IPAC 2011, San Sebastian, Spain, 2011, p.1177 		 
 
MOPA47 Planar Transmission Line BPM for Horizontal Aperture Chicane for XFEL pick-up, simulation, electronics, kicker 168
 
  • A. Angelovski, R. Jakoby, A. Penirschke
    TU Darmstadt, Darmstadt, Germany
  • C. Gerth, U. Mavrič, C. Sydlo
    DESY, Hamburg, Germany
  
  In order to obtain ultra-short bunches in the Free Electron Laser FLASH at DESY, the electron beam is compressed in magnetic chicanes. Precise knowledge of the beam position in the chicane is of great significance for the longitudinal dynamics control. In the current implementation cylindrical pickup-striplines mounted perpendicularly to the beam are used as a Beam Position Monitor (BPM)(*). One can determine the horizontal beam position by measuring the phase difference of the beam induced signal at opposite ends of a pickup. Due to the different electrical and mechanical requirements for the European XFEL a new BPM has to be developed. In this paper, we present the design and analysis of a planar transmission line structure which is planned to be used as a BPM in the European XFEL. The planar design of the pickups can provide for proper impedance match to the subsequent electronics as well as sufficient mechanical stability along the aperture when using alumina substrates. A scaled non-hermetic prototype of the BPM is built and characterized by scattering parameters. The measurement results are compared to simulations obtained by CST STUDIO SUITE®.
(*) K. Hacker at el, Proceedings of DIPAC 2007, Venice, Italy 2007, p.108 		 
 
MOPA48 Measurement of Temporal Resolution and Detection Efficiency of X-ray Streak Camera by Single Photon Images photon, timing, experiment, cathode 171
 
  • A. Mochihashi, M. Masaki, H. Ohkuma, S. Takano, K. Tamura
    JASRI/SPring-8, Hyogo-ken, Japan
  
  Funding: This work was partly supported by MEXT Grant-in-Aid for Young Scientists (B) Grant number 21740215.
In the third generation and the next generation synchrotron radiation light sources, the electron beam bunch length of ps ~ sub-ps is expected to be achieved. An X-ray streak camera (X-SC) can directly measure the temporal width of X-ray synchrotron radiation pulse. The temporal resolution of X-SC depends on the initial velocity distribution of the photoelectrons from a photocathode which converts the X-ray photons to the photoelectrons. To measure the temporal resolution of the X-SC, we have observed 'single photon' streak camera images and measured the temporal spread of the images. By this 'single photon' experiment, we have evaluated the dependence of the temporal resolution and the detection efficiency on the photon energy. We have also tried to evaluate the dependence of the temporal resolution and the detection efficiency on the thickness of the photocathode. For this purpose, we have developed a multi-array type CsI photocathode with 3 different thickness of the photocathode. The experimental setups, and the results of the measurements of the temporal spread and the detection efficiency of the single photon events will be presented. 		 
 
MOPA49 EO-sampling-based Temporal Overlap Control System for an HH Seeded FEL laser, FEL, operation, timing 176
 
  • S. Matsubara
    RIKEN/SPring-8, Hyogo, Japan
  • M. Aoyama
    JAEA/Kansai, Kyoto, Japan
  • A. Iwasaki, S. Owada
    The University of Tokyo, Tokyo, Japan
  • K. Ogawa, T. Sato, H. Tomizawa
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  • Y. Okayasu, T. Togashi, T. Watanabe
    JASRI/SPring-8, Hyogo-ken, Japan
  • E. Takahashi
    RIKEN, Saitama, Japan
  
  FELs have greatly interested for the short-wavelength region. However, their temporal profile and frequency spectra have shot-to-shot fluctuation by a SASE process. One of the promising approached for the problems is a seeded FEL scheme by using a full-coherent light source. The seeded FEL has been demonstrated in the EUV region by employ the high-order harmonics (HH) generation from an external laser source at the SCSS test-accelerator in the SPring-8. It is important for the HH-seeded FEL scheme to synchronize and overlap between the seeding laser pulse and the electron bunch. Their timing difference and laser spatial pointing is drifting. Therefore, a timing feedback and non-destructive monitor are necessary to operate seeded FEL continuously. We have constructed the timing monitor based on Electro-Optic (EO) sampling which is measure the timing difference the seeded laser pulse and the electron bunch simultaneously with the seeded FEL process. The probe laser pulse for the EO-sampling system is optically split from the common external HH laser driver for the seeded FEL. The EO-sampling system is able to use timing feedback for continual operation of the HH-seededFEL.  
 
MOPB55 Electron Cloud Measurements using Shielded Pickups at CesrTA simulation, detector, pick-up, synchrotron 198
 
  • J.P. Sikora, J.A. Crittenden, J.S. Ginsberg, D. L. Rubin
    CLASSE, Ithaca, New York, USA
  
  Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505.
The Cornell storage ring was originally a positron/electron collider with beam energies ranging from 2 to 5 GeV. In 2008 it was reconfigured as the Cornell Electron Storage Ring Test Accelerator (CesrTA). An important part of the research at CesrTA is the study of the growth, decay and mitigation of electron clouds. Electron Cloud (EC) densities can be measured with a Shielded Pickup (SPU), where cloud electrons pass into the detector through an array of small holes in the wall of the beam-pipe. The signals produced by SPU have proved to be very useful in measuring the mitigating effect of different vacuum chamber surfaces - including differences in quantum efficiency as well as secondary and elastic yield. This has been accomplished through the careful comparison of observed signals with the output of the EC simulation code ECLOUD. We present example comparisons of data and simulation that show the effect of different surfaces as well as beam conditioning effects. In addition, some data has been acquired using a solenoid to produce a longitudinal magnetic field at the SPU. We will present our current understanding of the effect of a longitudinal magnetic field on SPU signals. 		 
 
MOPB56 Electron Cloud Measurements using a Time Resolved Retarding Field Analyzer at CesrTA detector, dipole, positron, storage-ring 201
 
  • J.P. Sikora, M.G. Billing, J.V. Conway, J.A. Crittenden, Y. Li, X. Liu, D. L. Rubin, C.R. Strohman
    CLASSE, Ithaca, New York, USA
  • K. Kanazawa
    KEK, Ibaraki, Japan
  • M.A. Palmer
    Fermilab, Batavia, USA
  
  Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, the US Department of Energy DE-FC02-08ER41538, DE-SC0006505 and US-Japan funding.
The Cornell Electron Storage Ring has been reconfigured as a test accelerator (CesrTA) with positron or electron beam energies ranging from 2 GeV to 5 GeV. An area of research at CesrTA is the study of the growth, decay and mitigation of electron clouds in the storage ring. With a Retarding Field Analyzer (RFA), cloud electrons pass into the detector through an array of small holes in the wall of the beam-pipe. The electrons are captured by several collectors, so that the electron flux can be measured vs. horizontal position. Up to now, we have integrated the collector currents to provide DC measurements. We have recently constructed a new Time Resolved RFA, where the collector currents can be observed on the time scale of the bunch train in the storage ring. We present a summary of the design, construction and commissioning of this device, as well as initial beam measurements at CesrTA. 		 
 
MOPB57 Overview of Beam Instrumentation and Tuning at RIKEN RI Beam Factory ion, cyclotron, pick-up, acceleration 204
 
  • N. Fukunishi, M. Fujimaki, O. Kamigaito, M. Kase, M. Komiyama, J. Ohnishi, H. Okuno, N. Sakamoto, H. Watanabe, T. Watanabe, K. Yamada
    RIKEN Nishina Center, Wako, Japan
  • R. Koyama
    SHI Accelerator Service Ltd., Tokyo, Japan
  
  RIKEN RI Beam Factory (RIBF) was constructed as the first of the next-generation radioactive-beam facilities aiming at investigating vast unknown fields of unstable nuclei. In order to obtain the world-most intense heavy-ion beams, we have employed, taking into account cost effectiveness, a multistage acceleration scheme including 4 ring cyclotrons. We have already obtained 1 pμA, 0.42 pμA, and 24 pnA beams for 18O, 48Ca and 124Xe ions, respectively. The present performance has been obtained by using very conventional beam instruments such as Faraday cups, wire scanners and so on. Beam instruments used in RIBF are briefly summarized putting emphasis on beam tuning methods using them. In addition, limitations of these conventional devices and possible upgrade of beam instruments are discussed for further intensity upgrades and more stable operations of RIBF.  
 
MOPB60 Beam Diagnostics for AREAL RF Photogun Linac diagnostics, linac, gun, emittance 212
 
  • K. Manukyan, G.A. Amatuni, B. Grigoryan, V. Sahakyan, A. Sargsyan, G.S. Zanyan
    CANDLE, Yerevan, Armenia
  
  Advanced Research Electron Accelerator Laboratory (AREAL) based on photocathode RF gun is under construction at CANDLE. The basic approach to the new facility is the photocathode S-band RF electron gun followed by two 1 m long S-band travelling wave accelerating sections. Linac will operate in single bunch mode with final beam energy up to 20 MeV and the bunch charge 10 - 200 pC. In this paper the main approaches and characteristics of transverse and longitudinal beam diagnostics are presented.  
 
MOPB63 Emittance Measurement using X-ray Beam Profile Monitor at KEK-ATF emittance, controls, software, damping 215
 
  • T. Naito, H. Hayano, K. Kubo, S. Kuroda, N. Nakamura, T. Okugi, H. Sakai, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  
  The X-ray profile monitor (XPM) is used for the beam size measurement in the KEK-ATF damping ring(ATF-DR) at all times. The XPM consists of a crystal monochromator, two Fresnel zone plates(FZPs) and X-ray CCD camera. Two FZPs make the imaging optics. The design resolution of the selected wavelength 3.8nm is less than 1μm, which is sufficiently small for the emittance measurement of the ATF-DR. However, the measured results at the early stage were affected by the mechanical vibration. This paper describes the improvement of the resolution and the measurement results.  
 
MOPB65 Measurement of Sub-picosecond Bunch Length with the Interferometry from Double Diffraction Radiation Target radiation, target, detector, simulation 218
 
  • G.A. Naumenko, A. Potylitsyn, M.V. Shevelev, D.A. Shkitov
    TPU, Tomsk, Russia
  • H.X. Deng, S.L. Lu, T. Yu, J.B. Zhang
    SINAP, Shanghai, People's Republic of China
  
  Funding: This work was supported by the joint Russian-Chinese grant (RFBR N 110291177 and NSFC N 11111120065) and partially by the Program of Russian MES 'Nauka' and Chinese NSFC grant N 11175240.
Reliable and precise methods for non-invasive diagnostics of sub-picosecond electron bunches are required for new accelerator facilities (FEL, LWFA, et al.). Measurements of spectral characteristics of coherent radiation generated by such bunches using interferometer allow to determine a bunch length [1]. The interference pattern obtained by two diffraction radiation (DR) beams from two shifted plates (double DR target) may be used instead an interferometer [2]. Recently the coherent DR interferometry scheme at the SINAP accelerator facility was established [3]. Here we report the results of comparing the first measurement from such a technique with the measurement from Michelson interferometer. The parameters of fs linac are described in [4]. The DR target was consisted of two plates made from aluminum foil. The pyroelectric detector SPI-D-62 was used. The analysis of results from two techniques gives the same estimated bunch length about 660 fs (0.2 mm), which confirms the ability of the proposed technique for non-invasive bunch length measurements in the sub-picosecond range without a complicated scheme like Michelson interferometer or similar.
1. Murokh A.et al.,NIMA 410(1998)452
2. Potylitsyn A.P.,NIMB 227(2005)191
3. Shevelev M. et al.,Journal of Physics: Conference Series 357(2012)
4. Lin X.et al., Chin. Phys. Lett.27,4(2010)044101 		 
 
MOPB73 Beam Size and Intensity Diagnostics for a SRF Photoelectron Injector gun, cathode, solenoid, scattering 241
 
  • R. Barday, A. Jankowiak, T. Kamps, A.N. Matveenko, M. Schenk, J. Völker
    HZB, Berlin, Germany
  • F. Siewert
    BESSY GmbH, Berlin, Germany
  • J. Teichert
    HZDR, Dresden, Germany
  
  Funding: Work supported by Bundesministerium für Bildung und Forschung and Land Berlin
A high brightness photoelectron injector must be developed as a part of the BERLinPro program. The injector is designed to produce an electron beam with 100 mA average current and a normalized emittance of 1 mm*mrad. The project will be realized in two stages. First with a Pb cathode in a SRF gun, work ongoing, followed by a normal conducting CsK2Sb cathode capable of generating high current beams. In the first stage we have measured the fundamental beam parameters bunch charge, beam energy and energy spread with a special focus on the measurement of the transverse beam profiles. We also discuss our plans for the beam characterization at high currents. 		 
 
MOPB77 Adjustable Optics for a Non-destructive Beam Profile Monitor based on Scintillation of Residual Gas vacuum, operation, injection, detector 253
 
  • K. Reimers, V. Kamerdzhiev, A. Pernizki
    FZJ, Jülich, Germany
  
  The scintillation profile monitor (SPM) is being developed at COSY in addition to the existing ionisation profile monitor (IPM). Contrary to the IPM it does not require in-vacuum components, making it a robust and inexpensive instrument. The SPM is suitable for high intensity operation rather than operation with low intensity polarised beams. A multichannel PMT is used to detect scintillation light. The rate of detectable scintillation events is about three orders of magnitude lower compared to the rate of ionisation events. To boost the photon yield, small amounts of nitrogen are injected into the SPM vacuum chamber. An adjustable light focusing system is being built to optimise the SPM performance for different machine operation modes. The new system allows using a variety of optical components ranging from single lenses to high-grade camera objectives. Cylindrical lenses are considered to further boost the sensitivity by better fitting the beam image to the detector geometry. The latest experimental results and the new design of the optical system are presented.  
 
MOPB81 Residual Gas Ionization Profile Monitors in J-PARC Slow-extraction Beam Line proton, extraction, radiation, vacuum 267
 
  • Y. Sato, A. Agari, E. Hirose, M. Ieiri, Y. Katoh, M. Minakawa, R. Muto, M. Naruki, S. Sawada, Y. Shirakabe, Y. Suzuki, H. Takahashi, M. Takasaki, K.H. Tanaka, A. Toyoda, H. Watanabe, Y. Yamanoi
    KEK, Tsukuba, Japan
  • H. Noumi
    RCNP, Osaka, Japan
  
  Residual gas ionization profile monitors (RGIPMs) working in 1 Pa pressure have been developed for high-intensity proton beam (maximum: 50GeV-15uA) at J-PARC slow-extraction beam line. The transverse beam profiles are measured by collecting electrons produced by ionization of 1 Pa residual gas. The electrons are guided to the segmented electrode with a uniform electrostatic field applied in the gap. A uniform magnetic field is applied parallel to the electric field to reduce diffusion of electrons travelling to the electrodes. Typical spatial resolution of the RGIPMs with a 10 cm gap, a 10 V/cm electrostatic field, and a 400 gauss magnetic field at center is 0.5 mm. The collected charge is integrated during every extraction period (typically 2 second in 6 second accelerator cycle). Subtracting background distributions measured during off-beam period, profile distributions are measured clearly. The 14 RGIPMs installed in the slow-extraction beam line are working stably for the 30 GeV-0.46 uA proton beam at current maximum. In this contribution, detailed specifications and performance of the present RGIPMs will be reported.  
 
MOPB82 Bunch-Compressor Transverse Profile Monitors of the SwissFEL Injector Test Facility operation, laser, vacuum, undulator 271
 
  • G.L. Orlandi, M. Aiba, S. Bettoni, B. Beutner, H. Brands, R. Ischebeck, P. Peier, E. Prat, T. Schietinger, V. Schlott, V.G. Thominet
    PSI, Villigen PSI, Switzerland
  • C. Gerth
    DESY, Hamburg, Germany
  
  The 250 MeV SwissFEL Injector Test Facility (SITF) is the test bed of the future 5.7 GeV SwissFEL linac that will drive a coherent FEL light source in the wavelength range 7-0.7 and 0.7-0.1 nm. Aim of the SITF is to demonstrate the technical feasibility of producing and measuring 10 or 200pC electron bunches with normalized emittance down to 0.25 μm. A further goal is to demonstrate that the electron beam quality is preserved in the acceleration process, in the X-Band linearizer and the magnetic compression from about 10 ps down to 200 fs. The SITF movable magnetic bunch-compressor is equipped with several CCD/CMOS cameras for monitoring the beam transverse profile and determining the beam energy spread: a Ce:YAG screen and an OTR screen camera at the mid-point of the bunch compressor and a SR camera imaging in the visible the Synchrotron Radiation emitted by the electron beam crossing the third dipole. Results on the commissioning of such instrumentations, in particular in the low charge limit, and measurements of the beam energy spread vs. the compression factor will be presented.  
 
MOPB83 Turn-by-turn Observation of the Injected Beam Profile at the Australian Synchrotron Storage Ring injection, storage-ring, synchrotron, timing 276
 
  • M.J. Boland
    ASCo, Clayton, Victoria, Australia
  • T.M. Mitsuhashi
    KEK, Ibaraki, Japan
  • K.P. Wootton
    The University of Melbourne, Melbourne, Australia
  
  A fast gated intensified CCD camera was used to observe the beam profile turn-by-turn in the visible light region. Using the visible light from the optical diagnostic beamline on the storage ring at the Australian Synchrotron an optical telescope was constructed to focus an image on the ICCD. The event driven timing system was then used to synchronise the camera with the injected beam. To overcome the problem of dynamic range between the amount of charge in an injected bunch and the stored beam, the beam was dumped by slowly phase flipping the RF by 180 degrees between each one 1 Hz injection cycle. The injection process was verified to be stable enough so that measurements of the different turns could be captured on successive injections and did not need to be captured in single shot. The beam was seen to come in relatively cleanly in a tight beam but would then rapidly decohere due to the strong non-linear fields needed to run the storage ring at high chromaticity. It would take thousands of turns for the beam to damp down again and recohere into a tight beam spot again. This measurement technique will be used to tune the storage ring injection process.  
 
MOPB87 Development and First Tests of a High Sensitivity Charge Monitor for SwissFEL electronics, operation, FEL, instrumentation 287
 
  • S. Artinian, J.F. Bergoz, F. Stulle
    BERGOZ Instrumentation, Saint Genis Pouilly, France
  • P. Pollet, V. Schlott
    PSI, Villigen PSI, Switzerland
  
  The compact X-ray free electron laser SwissFEL, which is presently under development at the Paul Scherrer Institut (PSI) in Villigen, Switzerland, will operate at comparably low charges, allowing the compression of the electron bunches to a few femto-seconds (nominal 200 pC mode) and even towards the atto-second range (short bunch 10 pC mode). A high precision charge measurement turns out to be a challenge, especially in the presence of dark currents, which may occur from high gradient RF gun and accelerating structure operation. In response to this challenge, a higher sensitivity charge transformer and new beam charge monitor electronics were developed in collaboration between Bergoz Instrumentation and PSI. The Turbo-ICT captures sub-pC bunch charge thanks to a new magnetic alloy exhibiting very low core loss. Transmission over a carrier using narrow-band cable television technique preserves the signal integrity from the Turbo-ICT to the BCM-RF. Electro-magnetic and RF interferences are strongly attenuated; the dark current signal is suppressed. First beam test results, which have been performed at the SwissFEL Test Injector Facility (STIF), are presented in this contribution.  
 
MOPB88 Beam Size Monitor for TPS photon, synchrotron, radiation, synchrotron-radiation 291
 
  • C.K. Kuan, S.Y. Perng, I.C. Sheng, T.C. Tseng
    NSRRC, Hsinchu, Taiwan
  • J.-R. Chen
    National Tsing Hua University, Hsinchu, Taiwan
  
  The third-generation light source TPS is under construction in NSRRC. There are two diagnostic beamlines in the storage ring. Visible SR interferometers and X-ray pinhole cameras are widely used to measure the transverse beam profile in synchrotron light sources. In phase-I we will adopt the two methods to be the beam size monitor. The visible SR interferometer uses a double slit to obtain one-dimensional interference pattern along the horizontal or vertical axis. The simple X-ray pinhole camera is designed for the measurement of the size, the emittance and energy spread of the electron beam. In this paper we present the design and calculation of the two beam size monitors for TPS.  
 
TUCC01 Electron Storage Ring as a Single Shot Linac Beam Monitor injection, linac, synchrotron, emittance 302
 
  • Y. Shoji, K. Takeda
    LASTI, Hyogo, Japan
  • T. Asaka, Y. Minagawa, S. Suzuki, Y. Takemura
    JASRI/SPring-8, Hyogo-ken, Japan
  
  The SPring-8 linac has been operated as an injector to the electron storage ring, NewSUBARU. Because of the small acceptance of the ring, fine parameter tuning is required for the stable top-up injection. In that process, some single shot linac beam measurements were necessary to understand the shot-by-shot fluctuation of the injection efficiency. We used the electron ring itself as a linac beam monitor. The time-resolving visible light monitor in the ring records the profiles of the injected linac beam for many revolutions. The pulse width for the single rf bucket (500MHz) of the ring is normally 1 ns, which contains 3 linac bunches (2856MHz). The time profile in the ring gives the energy profile at after 1/4 of the synchrotron oscillation period. The spatial profile of several revolutions, recorded by a double-sweep streak camera or ICCD gated camera, gives a beam emittance of a single-shot. The streak camera enables the bunch by bunch measurement. The effective resolution depends on the beta function of the ring, which can easily be changed. For the vertical emittance, our spatial resolution of 0.3 mm FWHM at βy = 17 m was good enough to identify the quadrupole mismatch.  
slides icon Slides TUCC01 [1.481 MB]  
 
TUIC02 Direct Observation of the Dust-trapping Phenomenon vacuum, ion, high-voltage, experiment 315
 
  • Y. Tanimoto
    KEK, Ibaraki, Japan
  
  Dust trapping has long been an unwelcome and mysterious phenomenon in electron storage rings. As it leads to a sudden decrease in beam lifetime, dust trapping has been a perpetual nuisance at the Photon Factory Advanced Ring (PF-AR) since its beginning in the 1980s. However, during recent research on dust trapping at the PF-AR, video cameras serendipitously captured the culprit behind this phenomenon; the cameras recorded a luminous micro-particle trapped in the electron beam, just as if a shooting star were traveling in the beam tube. In the successive research, supersensitive cameras repeatedly observed trapped dust particles, and revealed that they behaved differently under different conditions. My presentation will summarize these experimental results, as well as long-term statistics supporting present dust-trapping theories.  
slides icon Slides TUIC02 [8.200 MB]  
 
TUPA05 The Calibration Factor Determined and Analysis for HLS Bunch Current Measurement System pick-up, storage-ring, experiment, data-analysis 334
 
  • Y.L. Yang, C. Cheng, P. Lu, T.J. Ma, B.G. Sun, J.G. Wang, J.Y. Zou
    USTC/NSRL, Hefei, Anhui, People's Republic of China
  
  Funding: Work supported by National Natural Science Project(11105141) and Chinese Universities Scientific Fund
For bunch current measurement, the calibration factor is a key parameter. Usually, button electrode or stripline electrode can be selected as signal pickup, and peak value or integral of bunch signal from pickup can be used to calculate the related bunch current value. To obtain the absolute value of bunch current, the calibration factor should be determined with the help of DCCT. At HLS, the Stretch effect of bunch length was observed when bunch current decay over time and this will affect the performance of bunch current detection for different pickup type and calculate method. Theoretical analysis and experimental validation results are performed to find out an ideal solution for bunch current measurement at HLS. The results show that, bunch current measurement system can obtain the best performance by stripline and its integral signal. 		 
 
TUPA06 Pulsed Electron Beam Current and Flux Monitor for the Race-track Microtron induction, microtron, controls, experiment 337
 
  • S.D. Dhole, S. Akhter, V.N. Bhoraskar, B.J. Patil, N.S. Shinde
    University of Pune, Pune, India
  
  In electron irradiation experiments on the materials, a true current of the electron beam is to be known to calculate the electron fluence received by the sample. Therefore, a pulsed electron beam current and flux monitor alongwith electronic system for an electron accelerator called Race-Track Microtron has been designed and developed. The sensing device used was a ferrite core having suitable number of turns of copper wire wound around it, through which the electron beam was passed without loss in the intensity. With an appropriate developed electronic circuit, the instantaneous value of the induced voltage was measured which in turn provides value of the electron beam pulsed current. The total charge passed through the ferrite core per unit time was therefore recorded and an integrated value of the total charge in a given period could be derived. This system can be used to measure the electron flux in the range from 108 electron/cm2 to 1016 electron/cm2. Moreover, this system has been used successfully in a few electron irradiation experiments where the knowledge of the electron fluence received by the sample is required.  
 
TUPA10 Optical-Fiber Beam Loss Monitor for the KEK Photon Factory injection, vacuum, storage-ring, kicker 351
 
  • T. Obina, Y. Yano
    KEK, Ibaraki, Japan
  
  Beam loss monitor system using optical fibers has been developed to determine the loss point of the injected beam at the KEK Photon Factory (PF) electron storage ring. Large-core optical fiber was installed along the vacuum chamber of the storage ring, of which circumference is about 187m. In order to cover the whole location, total 10 optical fibers with the length of 30 m is used. Both ends of the fiber has been fed out of the radiation shield of the ring. The Cherenkov light produced by the electron which is not captured in the ring, is detected by a photomultiplier tube (PMT) attached on the upstream side of the fiber. Rise-time of the PMT of 5 ns is fast enough to determine the location of the beam loss point. In the KEK-PF, two kinds of injection system, kicker magnets and a pulsed sextupole magnet (PSM), has been used for the routine operation. In this paper, details of the loss monitor system are reported and the difference of the two injection system will be discussed.  
 
TUPA11 SSRF BPM System Optimization and Upgrade brilliance, software, closed-orbit, injection 355
 
  • Y.B. Yan, Y.B. Leng
    SSRF, Shanghai, People's Republic of China
  • L.Y. Yu, W.M. Zhou
    SINAP, Shanghai, People's Republic of China
  
  The beam position monitor (BPM) system at SSRF was fully equipped with Libera Electrons. It have operated steadily for nearly five years. During the summer shutdown of 2012 more than 50 Libera Electrons were upgraded to Libera Brilliance which are used mainly for fast obit feedback system. The software of whole system is upgraded from 1.42 to 2.07. Some other hardware and software optimizations are carried out. After this upgrade, the stability and performance have been improved significantly. This paper introduces the details of the optimization and upgrade.  
 
TUPA16 HOM Choice Study with Test Electronics for use as Beam Position Diagnostics in 3.9 GHz Accelerating Cavities in FLASH cavity, HOM, dipole, electronics 364
 
  • N. Baboi, B. Lorbeer, P. Zhang
    DESY, Hamburg, Germany
  • N. Eddy, B.J. Fellenz, M. Wendt
    Fermilab, Batavia, USA
  
  Funding: Work supported in part by the European Commission within the Framework Programme 7, Grant Agreement 227579
Higher Order Modes (HOM) excited by the beam in the 3.9 GHz accelerating cavities in FLASH can be used for beam position diagnostics, as in a cavity beam position monitor. Previous studies of the modal choices within the complicated spectrum have revealed several options*: cavity modes with high coupling to the beam, and therefore with the potential for better position resolution, but which are propagating within all 4 cavities, and modes localized in the cavities or the beam pipes, which can give localized position information, but which provide worse resolution. For a better characterization of these options, test electronics has been built, which can down convert various frequencies between about 4 and 9 GHz to 70 MHz. The performance of various 20 MHz bands has been estimated. The best resolution of 20 μm was found for some propagating modes. Based on this study one band at ca. 5 GHz was chosen for high resolution position monitoring and a band at ca. 9 GHz for localized monitoring.
* N. Baboi et al., SRF2011, Chicago, IL, US 		 
 
TUPA19 First Tests of a Low Charge MTCA-based Electronics for Button and Strip-line BPM at FLASH electronics, detector, timing, operation 378
 
  • B. Lorbeer, N. Baboi, F. Schmidt-Föhre
    DESY, Hamburg, Germany
  
  Current FEL based light sources foresee operation with very short electron bunches. These can be obtained with charges of 100pC and lower. The specified charge range for FLASH, DESY, Hamburg goes from 100pC up to 1nC. The electronics currently installed at button and stripline BPMs of FLASH have been designed for best performance at higher charges and have reached their limits. Currently a new type of electronics is being developed at DESY to overcome these limitations. These electronics is/are conforming with the uTCA for physics standard(ref). This paper describes the next generation of FLASH BPM electronics suitable for button and stripline BPM. Furthermore the first measurement results taken with beam at FLASH, DESY are presented here.  
 
TUPA23 Performance of a Downconverter Test-electronics with MTCA-based Digitizers for Beam Position Monitoring in 3.9 GHz Accelerating Cavities HOM, electronics, cavity, monitoring 386
 
  • T. Wamsat, N. Baboi, B. Lorbeer
    DESY, Hamburg, Germany
  • P. Zhang
    UMAN, Manchester, United Kingdom
  
  Beam excited higher order modes (HOM) in 3.9GHz accelerating cavities at the European XFEL are planned to be used for beam position monitoring. The selected HOMs are located around 5440MHz and 9060MHz and are filtered in a bandwidth of 100MHz. A downconverter test electronics converts the HOMs to an intermediate frequency of 70MHz. The μTCA (Micro Telecommunications Computing Architecture) standard will be used for the XFEL. Thus it is important to have a performance study of the downconverter test electronics using the μTCA digitizer card SIS8300. In the digitizer IF frequency of 70MHz is undersampled with a clock frequency of 108MS/s. The paper will present the performance of the digitizer together with the test-electronics. A comparison with a 216MS/s VME (Versa Module Eurocard) digitizer will be made.  
 
TUPA41 Ultra-short Electron Bunch and X-ray Temporal Diagnostics with an X-band Transverse Deflecting Cavity FEL, photon, undulator, klystron 441
 
  • P. Krejcik, Y. Ding, J.C. Frisch, Z. Huang, H. Loos, J.W. Wang, M.-H. Wang
    SLAC, Menlo Park, California, USA
  • C. Behrens
    DESY, Hamburg, Germany
  • P. Emma
    LBNL, Berkeley, California, USA
  
  Funding: This work was supported by Department of Energy Contract No. DE-AC0276SF00515
The technique of streaking an electron bunch with a RF deflecting cavity to measure its bunch length is being applied in a new way at the Linac Coherent Light Source with the goal of measuring the femtosecond temporal profile of the FEL photon beam. A powerful X-band deflecting cavity is being installed downstream of the FEL undulator and the streaked electron beam will be observed at an energy spectrometer screen at the beam dump. The single-shot measurements will reveal which time slices of the streaked beam have contributed to the FEL process by virtue of their greater energy loss and energy spread relative to the non-lasing portions of the electron bunch. Since the diagnostic is located downstream of the undulator it can be operated continuously without interrupting the beam to the users. The resolution of the new X-band system will be compared to the existing S-band RF deflecting diagnostic systems at SLAC and consideration is given to the required RF phase stability tolerances required for acceptable beam jitter on the monitor. Simulation studies show that about 1 fs (rms) time resolution is achievable in the LCLS over a wide range of FEL wavelengths and pulse lengths. 		 
 
TUPA43 First Operation of the Electro-optical Sampling Diagnostics of the FERMI@Elettra FEL laser, FEL, alignment, vacuum 449
 
  • M. Veronese, A. Abrami, E. Allaria, M. Bossi, M.B. Danailov, M. Ferianis, L. Fröhlich, S. Grulja, M. Predonzani, F. Rossi, G. Scalamera, C. Spezzani, M. Trovò, M. Tudor
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  
  The FERMI@Elettra seeded FEL has demanding specifications in terms of longitudinal properties of the electron beam. Several diagnostics are installed along the linac. At the entrance of the FEL1 undulator chain an electro optical sampling (EOS) station based on the spatial encoding scheme is installed. The EOS provides both time jitter and longitudinal profile measurements in a non-destructive way. The layout of this system is described and the first operational measurement results obtained are reported. The paper includes also the capability of this diagnostics to perform the temporal coarse alignment of the seed laser to the electron beam. Finally a discussion on the future developments foreseen for this system is given.  
 
TUPA44 Status of the LCLS Experiment Timing System timing, laser, experiment, feedback 453
 
  • J.C. Frisch, C. Bostedt, R.N. Coffee, A.R. Fry, N. Hartmann, J. May, D.J. Nicholson, S. Schorb, S.R. Smith
    SLAC, Menlo Park, California, USA
  
  Funding: Work Supported by Department of Energy Contract DE AC03 76SF00515
X-ray / optical laser pump - probe experiments are used for a significant fraction of the scientific work performed at LCLS. The experimental laser systems are locked to the timing of the electron beam through a combination of RF and optical fiber based systems. The remaining ~100 femtosecond RMS jitter of the X-rays relative to the optical laser is measured shot-to-shot by both a RF timing detector, and by direct X-ray to optical cross-correlation, and the result is used to correct the experiment timing to 10s of femtoseconds. We present the present status of the system and plans for future upgrades. 		 
 
TUPB48 Beam Instrumentation for the COSY Electron Cooler gun, detector, laser, controls 468
 
  • V. Kamerdzhiev, L.J. Mao, K. Reimers
    FZJ, Jülich, Germany
  • E.A. Bekhtenev, V.N. Bocharov, M.I. Bryzgunov, A.V. Bubley, A.P. Denisov, G.V. Karpov, V.M. Panasyuk, V.V. Parkhomchuk, V.B. Reva
    BINP SB RAS, Novosibirsk, Russia
  • J. Dietrich
    HIM, Mainz, Germany
  
  The report deals with beam instrumentation of the electron cooler for COSY storage ring. The electron cooler is an electrostatic accelerator designed for beam energy up to 2 MeV and electron current up to 3 A with recuperation. The electron beam is immersed in longitudinal magnetic field so the electron motion is strongly magnetized. The control electrode in the electron gun is composed of four electrically isolated sectors. Applying AC voltage to one sector allows tracing of motion of that particular part of the beam. The electron beam shape is registered with the combination of 4-sector electron gun and the BPMs. This method allows observing both dipole and quadruple (galloping) modes of electron beam oscillation. Compass probe for measuring and tuning the direction of magnetic field in the cooling section is described. A profile monitor based on a few small Faraday cups for measuring distribution of the electron beam is presented.  
 
TUPB49 Electron Cloud Density Measurements using Resonant TE Waves at CesrTA resonance, simulation, storage-ring, positron 471
 
  • J.P. Sikora, M.G. Billing, D.O. Duggins, Y. Li, D. L. Rubin, R.M. Schwartz, K.G. Sonnad
    CLASSE, Ithaca, New York, USA
  • S. De Santis
    LBNL, Berkeley, California, USA
  
  Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505.
The Cornell Electron Storage Ring has been reconfigured as a test accelerator (CesrTA) with beam energies ranging from 2 GeV to 5 GeV of either positrons or electrons. Research at CesrTA includes the study of the growth, decay and mitigation of electron clouds in the storage ring. Electron Cloud (EC) densities can be measured by resonantly exciting the beam-pipe with microwaves. The EC density will change beam-pipe's resonant frequency by an amount that is proportional to the local electric field squared of the standing waves. When the EC density is not uniform, it is especially important to know the standing wave pattern in order to obtain an absolute EC density measurement. We will present our current understanding of this technique in the context of new test sections of beam-pipe installed in August 2012. This will include bench measurements of standing waves in the beam-pipe, simulations of this geometry and recent EC density measurements with beam. 		 
 
TUPB51 Gatling Gun Test Stand Instrumentation gun, cathode, diagnostics, emittance 474
 
  • D.M. Gassner, I. Ben-Zvi, J.C. Brutus, C. Liu, M.G. Minty, A.I. Pikin, O.H. Rahman, E.J. Riehn, J. Skaritka, E. Wang
    BNL, Upton, Long Island, New York, USA
  
  In order to reach the design eRHIC luminosity 50mA of polarized electron current is needed. This is far beyond what the present state-of-the-art polarized electron cathode can deliver. A high average polarized current injector based on the Gatling Gun principle is being designed. This technique will employ multiple cathodes and combine their multiple bunched beams along the same axis. A proof-of-principle test bench will be constructed that includes a 220 keV Gatling Gun, beam combiner, diagnostics station, and collector. The challenges for the instrumentation systems and the beam diagnostics that will measure current, profile, position, and halo will be described.  
 
TUPB57 Extreme Light Infrastructure (ELI Beamlines) - Research and Technology with new Ultra-short Pulse Intense Laser driven Sources of Energetic Photons and Charged Particles laser, proton, plasma, target 482
 
  • L. Pribyl, L. Juha, G. Korn, T. Levato, B. Rus, S. Ter-Avetisyan
    Czech Republic Academy of Sciences, Institute of Physics, Prague, Czech Republic
  • D. Margarone
    INFN/LNS, Catania, Italy
  • S. Sebban
    LOA, Palaiseau, France
  
  Funding: Czech Science Foundation (Project No. P205/11/1165), the Czech Republic's Ministry of Education, Youth and Sports to ELI-Beamlines (CZ.1.05/1.1.00/483/02.0061) and OPVK CZ.1.07/2.3.00/20.0087).
We will be giving an overview on the development of the 'ELI-Beamline facility', which will be a high-energy, repetition-rate laser pillar of the ELI (Extreme Light Infrastructure) project. It will be an international facility for both academic and applied research, slated to provide user capability since the beginning of 2016. The main purpose of the facility is the generation and applications of laser driven high-brightness X-ray sources and accelerated particles (electrons, protons and ions). The laser system will be delivering pulses with length ranging between 10 and 150 fs and will provide high-energy Petawatt and 10-PW peak powers. We will concentrate on the development of short photon wavelength (20 eV-100 keV) laser driven sources and their practical implementation. The sources are either based on direct interaction of the laser beam with a gaseous or solid target or will first accelerate electrons which then will interact with laser produced wigglers or directly injected into undulators. The main planned short pulse laser driven x-ray sources and their parameters will be presented together with requirements on the relevant beam detectors. 		 
 
TUPB60 Beam Diagnostics of Central Japan Synchrotron Radiation Research Facility Accelerator Complex synchrotron, booster, synchrotron-radiation, radiation 486
 
  • M. Hosaka, A. Mano, H. Morimoto, E. Nakamura, K. Takami, T. Takano, Y. Takashima, N. Yamamoto
    Nagoya University, Nagoya, Japan
  • Y. Hori
    KEK, Ibaraki, Japan
  • M. Katoh
    UVSOR, Okazaki, Japan
  • S. Koda
    SAGA, Tosu, Japan
  • A. Murata, K. Nakayama
    Toshiba, Yokohama, Japan
  • S. Sasaki
    JASRI/SPring-8, Hyogo-ken, Japan
  
  A new synchrotron radiation facility, Central Japan Synchrotron Radiation Research Facility is built in Aichi area. The light source accelerator complex consists of a 1.2 GeV compact electron storage ring and a full energy injector for top-up operation. The key equipments of the accelerator are four 5 T superconductive bending magnets. Although the acceleration energy of the storage ring is relatively low, synchrotron radiation from the superconductive bending magnet reaches hard X-ray region and can be provided for more than 10 beamlines. Construction of the facility started in 2010 and finished in Apr. 2012. Commissioning of the accelerator complex started in Mar. 2012. We adapted a turn-by-turn beam position monitoring system based on a digital oscilloscope developed at the UVSOR. In the presentation, we report on details of beam diagnostics conducted during the commissioning.  
 
TUPB61 The First Experience with the LHC Beam Gas Ionisation Monitor injection, emittance, controls, proton 489
 
  • M. Sapinski, W. Andreazza, B. Dehning, A. Guerrero, M. Patecki, R. Versteegen
    CERN, Geneva, Switzerland
  
  The Beam Gas Ionisation Monitors (BGI) are used to continuously measure the beam size at the LHC. This paper describes the detectors and their operation and discusses the issues encountered during the commissioning. It also discusses the various calibration procedures used to correct for non-uniformity of Multi-Channel plates and to correct the beam size for effects affecting the electron trajectory after ionisation.  
 
TUPB64 Methods to Reduce the System Error for High Power MSSW Emittance Meter emittance, ion, vacuum, ion-source 496
 
  • S.X. Peng, J. Chen, Z.Y. Guo, P.N. Lu, H.T. Ren, Y. Xu, Z.X. Yuan, J. Zhao
    PKU, Beijing, People's Republic of China
  
  Recently a new Multi-Slit Single-Wire (MSSW) type high power beam emittance meter named as HIBEMU-5 has developed in Peking University (PKU). Compared to previous MSSW devices, HIBEMU-5 greatly reduced the system error from 16.4% to 3.7% by specific designs to solve the incomplete short-slit sampling and fixed slit-wire distance. The problems of previous PKU devices are analyzed in part one. In part two, we describe the specific updating methods to solve its short-slit disadvantage by re-designing a longer-slit board with sufficient cooling, detail the mechanical scheme of changing the slit-wire distance for different beam divergence. The commissioning results given at part three prove that this new long slits design is successful to complete the beam sampling without being distorted by high power H+ beam. And the movable wire cup is able to locate the best measurement position for different beam focusing.  
 
TUPB69 Numerical Analysis on the Gain-reduction Characteristics of Multi-wire Proportional Chambers ion, simulation, cathode, space-charge 502
 
  • K. Katagiri, T. Furukawa, K. Noda
    NIRS, Chiba-shi, Japan
  
  Several MWPC (Multi-Wire Proportional Chamber) monitors are installed to diagnosis the beam profiles in the high-energy beam transport at HIMAC (Heavy Ion Medical Accelerator in Chiba) synchrotrons. When the intensity of the incident beams are much high, the gain reduction of the output signal from the MWPC monitor occurs due to the space charge effect of positive ions around the anode wires. The gain reduction is expected to be improved by changing geometric parameters, such as anode radius and distance between electrodes. In order to investigate the gain-reduction characteristics for different geometric parameters, we performed numerical simulation using a numerical code. The numerical code was developed using a two-dimensional drift-diffusion model to evaluate the gas gain including the reduction effect caused by the space charge effect of the moving positive ions. We investigate the gain-reduction rate for several parameters of the anode distance when changing the beam intensity. From these results, we discuss desirable distances between the anode wires to improve the gain reduction.  
 
TUPB73 Development of a Beam Profile Monitor using Nitrogen-Molecular Jet for Intense Beams proton, target, ion, photon 511
 
  • Y. Hashimoto, T. Toyama
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • T. Fujisawa, T.M. Murakami, K. Noda
    NIRS, Chiba-shi, Japan
  • Y. Hori, S. Muto, K. Yoshimura
    KEK, Ibaraki, Japan
  • T. Morimoto
    Morimoto Engineering, Iruma, Saitama, Japan
  • D. Ohsawa
    Kyoto University, Radioisotope Research Center, Kyoto-shi, Japan
  
  Funding: This work was supported by MEXT/JSPS KAKENHI Grant Number of 24310079 (Grant-in-Aid for Scientific Research(B)).
A non-destructive beam profile monitor using a sheeted jet beam of nitrogen molecular as a target has been developed for intense ion beams. The pressure of the sheeted molecular beam was 5 x 10-4 Pa at the beam collision point. A light emitted from excited nitrogen by an ion beam collision is measured by a high sensitive camera with a radiation resistant image intensifier. Verification of such a principle was already demonstrated with low-energy ion beams[1]. In this paper, some actual designs for intense beams of the J-PARC MR will be discussed mainly as bellow, intensity upgrade of the jet beam production, configuration of the detection chamber and its apparatus placed beam collision point, and the optical system for the light detection.
*[1] Y. Hashimoto, et al., Proc. of IPAC'10, Kyoto, Japan, p.987-989. 		 
 
TUPB76 Intra Undulator Screen Diagnostics for the FERMI@Elettra FEL FEL, laser, undulator, radiation 519
 
  • M. Veronese, A. Abrami, E. Allaria, M. Bossi, A. Bucconi, M. De Marco, M. Ferianis, L. Fröhlich, L. Giannessi, S. Grulja, R. Sauro, C. Spezzani, M. Tudor
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • T. Borden
    FRIB, East Lansing, Michigan, USA
  • F. Cianciosi
    ESRF, Grenoble, France
  
  The FERMI@Elettra seeded FEL poses demanding requirements in terms of intra undulator diagnostics due to the short wavelength of its FEL radiation and to the coexistence of the electron and photon FEL beams. An advanced multi-beam screen system has equipped both FEL1 and FEL2. The system has been designed for transverse size and profile measurement on both the electron beam and the FEL radiation. Challenging design constrains are present: COTR suppression, seed laser suppression, FEL wavelength range and minimization of the ionizing radiation delivered to the undulators. This paper describes the novel design and the obtained performance with the FERMI intra undulator screen system (IU-FEL).  
 
TUPB81 Design of the Beam Profile Monitors for the SXFEL Facility controls, detector, linac, FEL 534
 
  • L.Y. Yu, J. Chen, Y.B. Leng, K.R. Ye, W.M. Zhou
    SINAP, Shanghai, People's Republic of China
  
  The Shanghai X-ray Free Electron Laser Facility will begin construction at next year. The linac electron beam energy is 0.84 GeV. Over 50 beam profile monitors with OTR and YaG screen will be installed along the linac and undulators. The profile monitor system design is a challenging task, since the system has to measure transverse electron beam sizes from millimeter down to 40μm scale with a 20μm resolution and 50μm repeat positioning accuracy. This paper describes the design of the mechanical detector , the integrated step-servo motor controlling system, the beam imaging system, as well as the software system.  
 
TUPB84 Storage Ring Tune Measurements using High-speed Metal-semiconductor-metal Photodetector synchrotron, storage-ring, coupling, detector 537
 
  • S. Dawson, D.J. Peake, R.P. Rassool
    The University of Melbourne, Melbourne, Australia
  • M.J. Boland
    ASCo, Clayton, Victoria, Australia
  • R.J. Steinhagen
    CERN, Geneva, Switzerland
  
  Knowledge of the betatron tunes within a storage ring is important to prevent the creation of instabilities and maximise the lifetime of the stored current within the ring. Typical tune measurements excite the beam and measure the resulting motion over time using electromagnetic pickups. The novel measurement technique presented utilises high-speed MSM photodiodes in a balanced detector set-up to measure the vertical and horizontal betatron tunes. Radiation from a bending magnet consists of both visible light and X-rays. The visible light is separated from the X-rays with an optical chicane and focussed onto a pair of length-matched optical fibers each coupled to an MSM photodiode. The specialised biasing circuit for the photodiodes is constructed in a balanced detector configuration to emphasise any motion in the beam. Signal resulting from beam motion is amplified and digitised for analysis. Using this set-up the tunes for the storage ring at the Australian Synchrotron have been measured and verified with comparison to existing tune measurement technologies. The results from the new optical tune measurement system will be presented and discussed.  
 
TUPB85 Spectrum of Multi-bunch Position Model and Parameter Acquisition Algorithm storage-ring, injection, wakefield, experiment 540
 
  • Y. Yang, Y.B. Leng
    SSRF, Shanghai, People's Republic of China
  • B.P. Wang
    SINAP, Shanghai, People's Republic of China
  
  Based on the spectrum of turn-by-turn model for the storage ring, spectrum of multi-bunch position model was derived through some assumptions. Spectrum of excited electron beam position was analyzed in Shanghai Synchrotron Radiation Facility(SSRF) and Genetic Algorithm was used to obtain the model parameters when fitting multi-curve data. Results show that, after 100 times iteration, all the correlation of fitted data and original data can be up to 95%, and the model can accurate estimate a bimodal split of the spectrum curve.  
 
WECC04 Analysis of the Electro-optical Front End for the New 40 GHz Bunch Arrival Time Monitor System laser, pick-up, timing, FEL 571
 
  • A. Kuhl, J. Rönsch-Schulenburg, J. Roßbach
    Uni HH, Hamburg, Germany
  • A. Angelovski, R. Jakoby, A. Penirschke
    TU Darmstadt, Darmstadt, Germany
  • M. Bousonville, M.K. Czwalinna, H. Schlarb, C. Sydlo
    DESY, Hamburg, Germany
  • S. Schnepp
    IFH, Zurich, Switzerland
  • T. Weiland
    TEMF, TU Darmstadt, Darmstadt, Germany
  
  The Free electron LASer in Hamburg (FLASH) is currently equipped with four Bunch Arrival time Monitors (BAMs) which achieve a time resolution of less than 10 fs for bunch charges higher than 500 pC (1). In order to achieve single spike FEL pulses at FLASH, electron bunch charges down to 20 pC are of interest. With the current BAMs the required time resolution is not reachable for bunch charges below 500 pC. Therefore new pickups with a bandwidth of up to 40 GHz (2) are designed and manufactured. The signal evaluation takes place with a time-stabilized reference laser pulse train which is modulated with an Electro-Optical intensity Modulator (EOM). The new pickup system also requires a new electro-optical frontend with a 40 GHz EOM. The theoretical limits of the time resolution depending on the RF signal at different bunch charges and on the jitter of the reference laser pulses where analyzed for the new EOM.
(1) M. K. Bock et al. in Proceedings of DIPAC 2011, Hamburg, Germany,2011, p. 365
(2) A. Angelovski, A. Kuhl et al. in Proceedings of IPAC 2011, San Sebastian, Spain, 2011, p. 1177 and p. 1186
 		 
slides icon Slides WECC04 [12.560 MB]  
 
WECD01 Operation of a Single Pass, Bunch-by-bunch x-ray Beam Size Monitor for the CESR Test Accelerator Research Program detector, positron, optics, vacuum 585
 
  • N.T. Rider, M.G. Billing, M. P. Ehrlichman, M.A. Palmer, D.P. Peterson, D. L. Rubin, J.P. Shanks, K.G. Sonnad
    CLASSE, Ithaca, New York, USA
  • J.W. Flanagan
    KEK, Ibaraki, Japan
  
  Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467, and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505.
The CESR Test Accelerator (CesrTA) program targets the study of beam physics issues relevant to linear collider damping rings and other low emittance storage rings. This endeavor requires new instrumentation to study the beam dynamics along trains of ultra low emittance bunches. A key element of the program has been the design, commissioning and operation of an x-ray beam size monitor capable, on a turn by turn basis, of collecting single pass measurements of each individual bunch in a train over many thousands of turns. This new instrument utilizes custom, high bandwidth amplifiers and digitization hardware and firmware to collect signals from a linear InGaAs diode array. The instrument has been optimized to allow measurements with 3x109 to 1x1011 particles per bunch. This paper reports on the operational capabilities of this instrument, improvements for its performance, and the methods utilized in data analysis. Examples of key measurements which illustrate the instrument's performance are presented. This device demonstrates measurement capabilities applicable to future high energy physics accelerators and light sources. 		 
slides icon Slides WECD01 [3.480 MB]  
 
THCB01 Electron-Lens Test Stand Instrumentation Progress gun, laser, instrumentation, cathode 602
 
  • T.A. Miller, J.N. Aronson, D.M. Gassner, X. Gu, A.I. Pikin, P. Thieberger
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by B.S.A, LLC under contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In preparation for installation of Electron Lenses into RHIC, planned for late 2012, a working test stand is in use testing the performance of the gun, collector, modulator, instrumentation and controls. While testing & operating the instrumentation, both progress and pitfalls were encountered. Results are presented from issues including ground loop signals generated by the DCCTs, static magnetic field interference, competing YAG screen illumination techniques, YAG crystal damage during beam operation, performance of the four quadrant beam scraper electrodes, and challenges in measuring beam current in conductors. Working knowledge and insight into each of these systems has been gained through difficulties leading to success. These insights are presented with supporting data and images. 		 
slides icon Slides THCB01 [32.453 MB]