Keyword: vacuum
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MOCL02 Harmonically Resonant Cavity as a Bunch Length Monitor cavity, electron, laser, real-time 24
 
  • B.F. Roberts, M.H. Pablo
    Electrodynamic, Albuquerque, New Mexico, USA
  • M.M. Ali
    ODU, Norfolk, Virginia, USA
  • E. Forman, J.M. Grames, F.E. Hannon, R. Kazimi, W. Moore, M. Poelker
    JLab, Newport News, Virginia, USA
 
  Funding: US DOE DE-SC0009509
RF cavities have been designed and constructed that simultaneously and exclusively resonate many harmonic TMono modes. These modes are axially symmetric and have their electric field maximum along the cavities bore. A periodic beam passing through a harmonic cavities bore excites these modes whose superposition can be measured at the cavities antenna with a sampling oscilloscope. Processing the detected waveform with the harmonic cavities transfer function yields the Fourier series of the beam, and a near real-time, non-invasive measurement of the beams longitudinal bunch shape and duration. Experiments have been performed on the 130 kV injector at the Thomas Jefferson National Accelerator Facilities Continuous Electron Beam Accelerator Facility. The harmonic cavities sensitivity was near 1 mV/μA and measured beam bunches ranging in width from 45 to 150 picoseconds (FWHM). These measurements were in close agreement with measurements made using an invasive bunch measurement system as well as predictions by a particle tracking simulations.
 
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOCL02  
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MOPG03 Investigation of Transverse Beam Instability Induced by an In-vacuum Undulator at SPEAR3 simulation, coupling, operation, insertion-device 31
 
  • K. Tian, J.J. Sebek, J.L. Vargas
    SLAC, Menlo Park, California, USA
 
  Funding: Work supported by U.S. Department of Energy Contract No. DE-AC02-76SF00515
Vertical beam instabilities have been observed at SPEAR3 when a newly installed in-vacuum undulator (IVUN) is operated at a set of narrow gap settings. The source of the instabilities is believed to be vertically deflecting trapped modes inside the IVUN tank that are excited by the beam. We have used beam-based measurements to characterize the frequencies and strengths of the excited modes using both our bunch-by-bunch feedback system and a spectrum analyzer. Using numerical simulations of our IVUN structure, we have found modes with high shunt impedance near the measured frequencies. Recently, we have successfully measured these IVUN modes during our current downtime. In this paper, we will report on the measurements, simulations, and plans to damp these modes.
 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG03  
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MOPG10 BPM Stabiltiy Studies for the APS MBA Upgrade detector, ground-motion, diagnostics, experiment 55
 
  • R.M. Lill, N. Sereno, B.X. Yang
    ANL, Argonne, Illinois, USA
 
  Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The Advanced Photon Source (APS) is currently in the preliminary design phase for the multi -bend achromat (MBA) lattice upgrade. Beam stability is critical for the MBA and will require long term drift defined as beam motion over a seven-day timescale to be no more than 1 micron at the insertion device locations and beam angle change no more than 0.5 micro-radian. Mechanical stability of beam position monitor (BPM) pickup electrodes mounted on insertion device vacuum chambers place a fundamental limitation on long-term beam stability for insertion device beamlines. We present the design and implementation of using prototype mechanical motion system (MMS) instrumentation for quantifying this type of motion specifically in the APS accelerator tunnel and experiment hall floor under normal operating conditions. The MMS presently provides critical position information on the vacuum chamber and BPM support systems. Initial results of the R&D prototype systems have demonstrated that the chamber movements far exceed the long-term drift tolerance specified for the APS Upgrade MBA storage ring.
 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG10  
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MOPG20 Optimized Beam Loss Monitor System for the ESRF detector, injection, electron, controls 86
 
  • K.B. Scheidt, F. Ewald
    ESRF, Grenoble, France
  • P. Leban
    I-Tech, Solkan, Slovenia
 
  Monitoring of the 6 GeV electron losses around the ESRF storage ring is presently done by a hybrid system consisting of ionization chambers and scintillators. It allows a rough localization of the losses, but has numerous limitations : size, weight, time-resolution, sensitivity, versatility, and costs. A new system was developed consisting of a detector head (BLD) and the electronics for signal acquisition and control (BLM). The BLD is compact, based on a scintillator coupled to a small photo-multiplier module. The BLM controls 4 independent BLDs and acquires data with sampling rates up to 125 MHz. Measurements performed on different configurations of BLD prototypes have lead to an optimized design that allows, together with the flexible signal processing performed in the BLM, to cover a wide range of applications: measurement of fast and strong losses during injection is just as well possible as detection of very small variations of weak losses during the slow current decay. This paper describes the BLD/BLM design, its functionality and performance characteristics, and shows results from prototypes installed in the injection zone and in close vicinity to in-vacuum undulators.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG20  
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MOPG22 Studies and Historical Analysis of ALBA Beam Loss Monitors storage-ring, injection, detector, operation 94
 
  • A.A. Nosych, U. Iriso
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
 
  During 5 years of operation in the 3 GeV storage ring of ALBA, the 124 beam loss monitors (BLM) have provided stable measurements of relative losses around the machine, with around 10% breakdown of units. We have analyzed these BLM failures and correlated the integrated received dose with any special conditions of each BLM location which might have led to their breakdown. We also show studies of beam losses in the insertion devices, with particular attention to the results in the multipole wiggler (MPW), where the vacuum chamber is (suspected to be) misaligned and high BLM counts are detected.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG22  
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MOPG41 A New Wall Current Monitor for the CERN Proton Synchrotron impedance, proton, synchrotron, simulation 143
 
  • J.M. Belleman, W. Andreazza
    CERN, Geneva, Switzerland
  • A.A. Nosych
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
 
  Wall Current Monitors are the devices of choice to observe the instantaneous beam current in proton accelerators. These entirely passive transformers deliver a high-fidelity image of the beam intensity in a bandwidth spanning from about 100kHz up to several GHz. They serve as a signal source for a diverse set of applications including Low Level RF feedback and longitudinal diagnostics such as bunch shape measurements and phase-space tomography. They are appreciated for their excellent reliability, large bandwidth and unsurpassed dynamic range. We describe the design of a new Wall Current Monitor for the CERN Proton Synchrotron with a useful bandwidth of 100kHz to 4GHz. Two such devices have been installed in the PS machine and are now used in regular operation. Some usage examples will be shown.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG41  
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MOPG61 AXD Measurements at SOLEIL dipole, electron, radiation, photon 209
 
  • M. Labat, M. El Ajjouri, N. Hubert, D. Pédeau, M. Ribbens, M.-A. Tordeux
    SOLEIL, Gif-sur-Yvette, France
 
  A first prototype of in-Air X-ray Detector (AXD) has been installed on the SOLEIL storage ring. An AXD simply consists of a scintillator, an objective and a camera installed in air behind the absorber of the bending magnet's synchrotron radiation layer. The radiation vertical profile analysis easily enables to retrieve the vertical beam size of the electron beam at the source point. This simple diagnostics opens large perspectives of beam size measurement all around the ring for an accurate caracterization of the beam and improvment of its stability survey.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG61  
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MOPG62 Novel Grating Designs for a Single-Shot Smith-Purcell Bunch Profile Monitor radiation, detector, electron, background 213
 
  • A.J. Lancaster, G. Doucas, H. Harrison, I.V. Konoplev
    JAI, Oxford, United Kingdom
 
  Funding: This work was supported by the STFC UK (grant ST/M003590/1) and the Leverhulme Trust (International Network Grant IN-2015-012). H. Harrison is supported by STFC UK and the JAI for her DPhil.
Smith-Purcell radiation has been successfully used to perform longitudinal profile measurements of electron bunches with sub-ps lengths. These measurements require radiation to be generated from a series of gratings to cover a sufficient frequency range for accurate profile reconstruction. In past systems the gratings were used sequentially and so several bunches were required to generate a single profile, but modern accelerators would benefit from such measurements being performed on a bunch by bunch basis. To do this the radiation from all three gratings would need to be measured simultaneously, increasing the mechanical complexity of the device as each grating would need to be positioned individually and at a different azimuthal angle around the electron beam. Investigations into gratings designed to displace the radiation azimuthally will be presented. Such gratings could provide an alternative to the rotated-grating approach, and would simplify the design of the single-shot monitor by reducing the number of motors required as all of the gratings could be positioned using a single mount.
 
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG62  
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MOPG66 Design and Experimental Tests of the SwissFEL Wire-Scanners electron, FEL, operation, radiation 225
 
  • G.L. Orlandi, R. Ischebeck, C. Ozkan Loch, V. Schlott
    PSI, Villigen PSI, Switzerland
  • M. Ferianis, G. Penco
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
 
  The SwissFEL wire-scanner (WSC) composes of an in-vacuum beam-probe - motorized by a stepper motor - and an out-vacuum pick-up of the wire-signal. In SwissFEL, WSCs will absolve two main tasks: high precision measurement of the beam profile for determining the beam emittance as a complement to view-screens; routine monitoring of the beam profile under FEL operations. In order to fulfill the aforementioned tasks, the design of the in-vacuum component of the SwissFEL WSCs followed the guidelines to ensure a mechanical stability of the scanning wire at the micrometer level as well as a significative containment of the radiation-dose release along the machine thanks to the choice of metallic wires with low density and Atomic number. Beam-loss monitors have been suitably designed to ensure a sufficient sensitivity and dynamics to detect signals from scanned beams in the charge range 10-200 pC. The design, the prototyping phases, the bench and electron-beam tests - performed at SITF (Paul Scherrer Institut) and FERMI (Elettra, Trieste) - of the entire SwissFEL WSC set-up will be presented.
Contribution accepted for publication in Physical Review Accelerators and Beams
 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG66  
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MOPG68 Development and Commissioning of the Next Generation X-ray Beam Size Monitor in CESR detector, operation, alignment, storage-ring 229
 
  • N.T. Rider, S.T. Barrett, M.G. Billing, J.V. Conway, B.K. Heltsley, A.A. Mikhailichenko, D.P. Peterson, D. L. Rubin, J.P. Shanks, S. Wang
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Funding: Work supported by NSF grant PHY-0734867, PHY-1002467 and DOE grant 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. The x-ray beam size monitor development has matured to include the design of a new instrument which has been permanently integrated into the storage ring. A new beam line has been designed and constructed which allows for the extraction of x-rays from the positron beam using a newly developed electro magnet pair. This new instrument utilizes custom, high bandwidth amplifiers and digitization hardware and firmware to collect signals from a linear InGaAs diode array. This paper reports on the development of this new instrument and its integration into storage ring operation including vacuum component design, electromagnet design, electronics and capabilities.
 
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MOPG74 Design and Performance of Coronagraph for Beam Halo Measurements in the LHC injection, scattering, synchrotron, background 253
 
  • A. Goldblatt, E. Bravin, F. Roncarolo, G. Trad
    CERN, Geneva, Switzerland
  • T.M. Mitsuhashi
    KEK, Ibaraki, Japan
 
  The CERN Large Hadron Collider is equipped with two Beam Synchrotron Radiation (BSR) systems, one per beam, used to monitor the transverse distribution of the beam, its longitudinal distribution and the abort gap population. During the 2015-2016 winter shut-down period, one of the two BSR systems was equipped with a prototype beam halo monitor, based on the coronagraph technique, classically used in astrophysics telescopes to measure the sun corona. The system design, as well as its optics, was inherited from the coronagraph used in the KEK Photon Factory with some modifications made in order to satisfy the LHC BSR source constraints. This project is in the framework of the HL-LHC project, for which there is the requirement to monitor the beam halo at the level of 10-6 of the core intensity. This first prototype has been designed as a demonstrator system aimed at resolving a halo-core contrast in the 10-3 to 10-4 range. After discussing the design of the LHC coronagraph and its technical implementation, this contribution presents the result of the first tests with beam and the planned system upgrades for 2017.  
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MOPG78 Scintillation and OTR Screen Characterization with a 440 GeV/c Proton Beam in Air at the CERN HiRadMat Facility proton, photon, radiation, controls 268
 
  • S. Burger, B. Biskup, S. Mazzoni, M. Turner
    CERN, Geneva, Switzerland
  • B. Biskup
    Czech Technical University, Prague 6, Czech Republic
  • M. Turner
    TUG/ITP, Graz, Austria
 
  Beam observation systems, based on charged particles passing through a light emitting screen, are widely used and often crucial for the operation of particle accelerators as well as experimental beamlines. The AWAKE experiment, currently under construction at CERN, requires a detailed understanding of screen sensitivity and the associated accuracy of the beam size measurement. We present the measurement of relative light yield and screen resolution of seven different materials (Chromox, YAG, Alumina, Titanium, Aluminium, Aluminium and Silver coated Silicon). The Chromox and YAG samples were additionally measured with different thicknesses. The measurements were performed at the CERN's HiRadMat test facility with 440 GeV/c protons, a beam similar to the one foreseen for AWAKE. The experiment was performed in an air environment.  
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TUCL02 Novel Accelerator Physics Measurements Enabled by NSLS-II RF BPM Receivers impedance, closed-orbit, factory, feedback 294
 
  • B. Podobedov, W.X. Cheng, Y. Hidaka
    BNL, Upton, Long Island, New York, USA
  • D. Teytelman
    Dimtel, San Jose, USA
 
  NSLS-II light source has state of the art RF BPM receivers that were designed and built in-house incorporating the latest technology available in the RF, digital, and software domains. The recently added capability to resolve the orbits of multiple bunches within a turn as well as further improvement in transverse positional resolution for single- and few-bunch fills [*] allowed us to perform a number of novel beam dynamics measurements. These include measuring small impedances of vacuum chamber components, and of extremely small (~10-5) current-dependent tune shifts (transverse and synchrotron), as well as obtaining an amplitude-dependent tune shift curve from a single kicker pulse. We are also effectively utilizing our BPMs to decipher the lifetimes of individual bunches and to visualize single bunch instability dynamics. In this paper we review the unique capabilities of NSLS-II BPMs and present examples of beam physics measurements that greatly benefit from them.
* B. Podobedov, W. Cheng, K. Ha, Y. Hidaka, J. Mead, O. Singh, K. Vetter "Single Micron Single-Bunch Turn-by-Turn BPM Resolution Achieved at NSLS-II", in Proc. IPAC'16, Busan, Korea, May 2016, WEOBB01
 
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUCL02  
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TUPG07 Commisioning of Beam Position and Phase Monitors for LIPAc pick-up, coupling, simulation, electronics 326
 
  • I. Podadera, A. Guirao, D. Jiménez-Rey, L.M. Martínez, J. Mollá, A. Soleto, R. Varela
    CIEMAT, Madrid, Spain
 
  Funding: Work partially supported by the Spanish Ministry of Science and Innovation under project AIC-A-2011-0654 and FIS2013-40860-R
The LIPAc accelerator will be a 9 MeV, 125 mA CW deuteron accelerator which aims to validate the technology that will be used in the future IFMIF accelerator. Several types of Beam Position Monitors BPMs- are placed in each section of the accelerator to ensure a good beam transport and minimize beam losses. LIPAc is presently under installation and commissioning of the second acceleration stage at 5 MeV. In this stage two types of BPMs are used: four striplines to control the position at the Medium Energy Beam Transport line (MEBT), and three striplines to precisely measure the mean beam energy at the Diagnostics Plate. The seven pickups have been installed and assembled in the beamlines after characterization in a wire test bench, and are presently been commissioned in the facility. In addition, the in-house acquisition system has been fully developed and tested in the wire test bench at CIEMAT. In this contribution, the results of the beam position monitors characterization, the tests carried out during the assembly and the first measurements with the electronics system will be reported.
 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG07  
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TUPG18 Design Optimization of Button-Type BPM Electrode for the SPring-8 Upgrade resonance, impedance, simulation, storage-ring 360
 
  • M. Masaki, H. Dewa, T. Fujita, S. Takano
    JASRI, Hyogo, Japan
  • H. Maesaka, S. Takano
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
 
  The requirements for a BPM system for the SPring-8 upgrade are long-term stability, sufficient signal intensity and high accuracy*. The design of a button-type electrode for the BPM has been optimized from the perspectives of 1) mechanical structure, 2) rf characteristics, 3) thermal issue. We have adopted the electrode structure without a sleeve enclosing the button to maximize the button diameter for the narrow aperture of the vacuum chamber. The absence of an annular slot around the sleeve in a lodging hole for the electrode eliminates the associated beam impedance. To minimize the beam impedance and the trapped mode heating of the electrode, the rf structure has been optimized by 3D electro-magnetic simulations. To suppress the ohmic loss on the button and center pin thermally isolated from the water cooled BPM block, we have selected molybdenum as a material with high electric and thermal conductivities. The reduction of the heating suppresses thermal deformation of the electrode and the BPM block, and improves thermal stability of the BPM system. The mechanical tolerance of the electrode was defined to fit the error budget for the total BPM offset error of 0.1 mm rms.
* H. Maesaka et al., in this conference.
 
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TUPG20 The CMS Beam Halo Monitor at the LHC: Implementation and First Measurements detector, background, experiment, luminosity 364
 
  • N. Tosi
    INFN-Bologna, Bologna, Italy
 
  A Cherenkov based detector system has been installed at the Large Hadron Collider (LHC), in order to measure the Machine Induced Background (MIB) for the Compact Muon Solenoid (CMS) experiment. The system is composed of forty identical detector units formed by a cylindrical Quartz radiator directly coupled to a Photomultiplier. These units are installed at a radius of 1.8m and a distance of 20.6 m from the CMS interaction point. The fast and direction-sensitive signal allows to measure incoming MIB particles while suppressing the much more abundant collision products and albedo particles, which reach the detector at a different time and from a different direction. The system readout electronics is based on the QIE10 ASIC and a uTCA based back-end, and it allows a continuous online measurement of the background rate separately per each bunch. The detector has been installed in 2015 and is now fully commissioned. Measurements demonstrating the capability of detecting anomalous beam conditions will be presented.
on behalf of the CMS collaboration
 
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TUPG40 The Cherenkov Detector for Proton Flux Measurement (CpFM) in the UA9 Experiment detector, experiment, proton, radiation 430
 
  • S. Montesano, W. Scandale
    CERN, Geneva, Switzerland
  • F.M. Addesa, G. Cavoto, F. Iacoangeli
    INFN-Roma, Roma, Italy
  • L. Burmistrov, S. Dubos, V. Puill, W. Scandale, A. Stocchi
    LAL, Orsay, France
 
  The UA9 experiment at the CERN SPS investigates the possibility to use bent crystals to steer particles in high energy accelerators. In this framework the CpFM have been developed to measure the beam particle flux in different experimental situations. Thin movable fused-silica bars installed in the SPS primary vacuum and intercepting the incoming particles are used to radiate Cherenkov light. The light signal is collected outside the beam pipe through a quartz optical window by radiation hard PMTs. The PMT signal is readout by the WaveCatcher acquisition board, which provides count rate as well as waveform information over a configurable time window. A bundle of optical fibers can be used to transport the light signal far from the beam pipe, allowing to reduce the radiation dose to the PMT. A first version of the CpFM has been successfully commissioned during the data taking runs of the UA9 Experiment in 2015, while a second version has been installed in the TT20 extraction line of the SPS in 2016. In this contribution the design choices will be presented and the final version of the detector will be described in detail.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG40  
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TUPG67 Recent Results From New Station for Optical Observation of Electron Beam Parameters at KCSR Storage Ring electron, diagnostics, synchrotron, storage-ring 508
 
  • O.I. Meshkov, V.M. Borin, A.D. Khilchenko, A.I. Kotelnikov, A.N. Kvashnin, L.M. Schegolev, A.N. Zhuravlev, E.I. Zinin, P.V. Zubarev
    BINP SB RAS, Novosibirsk, Russia
  • V.L. Dorokhov
    BINP, Novosibirsk, Russia
  • V. Korchuganov, G. Kovachev, D.G. Odintsov, A.I. Stirin, Yu.F. Tarasov, A.G. Valentinov, A.V. Zabelin
    NRC, Moscow, Russia
 
  New station for optical observation of electron beam parameters is being designed at KCSR SIBERIA-2 storage ring in collaboration with Budker Institute of Nuclear Physics, Novosibirsk, Russia. For the purpose of easy operation, control and alignment, the new station is located outside the shielding wall of the storage ring. The station serves for the automatic measurement of electron bunches transverse and longitudinal sizes with the use of SR visible spectrum in one-bunch and multi-bunch modes; the study of individual electron bunches behavior in time with changing accelerator parameters; the precise measurement of betatron and synchrotron oscillations frequency. The station contains the set of diagnostics: double-slit interferometer, CCD camera, optical dissector, TV camera and two linear avalanche photodiodes arrays. New optical observation station meets the requirements of accelerator physics experiments and experiments with the use of SR related to the knowledge of exact parameters of separate electron bunches. The recent experimental results obtained with the diagnostics are described.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG67  
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TUPG80 Design and Implementation of Non-Invasive Profile Monitors for the ESS LEBT alignment, proton, photon, controls 551
 
  • C.A. Thomas, T. Galh, T.J. Grandsaert, H. Kocevar, J.H. Lee, A. Serrano, T.J. Shea
    ESS, Lund, Sweden
 
  We present in this paper the design and implementation of the Non-invasive Profile Monitors for the ESS LEBT. Non-invasive Profile Monitors at ESS measure the transverse profile of the high power proton beam. As such the NPM for the LEBT is not different from NPM designed for other sections of the ESS linac, however, it received the requirement to measure the position of the beam accurately with respect to the centre of the vacuum chamber, representing the reference orbit. This particular requirement led to implement a specific design to provide absolute position measurement to the system. In the following we will first describe the design and the associated functionalities, and then we will present the performance measurements of this built system, fully integrated into the control system. Finally we will discuss the performance in comparison to the initial requirements.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG80  
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WEAL02 The Wall Current Transformer - a New Sensor for Precise Bunch-by-Bunch Intensity Measurements in the LHC impedance, instrumentation, network, operation 568
 
  • M. Krupa, M. Gąsior
    CERN, Geneva, Switzerland
 
  The Wall Current Transformer (WCT) is a new bunch-by-bunch intensity monitor developed by the CERN Beam Instrumentation Group to overcome the performance issues of commercial Fast Beam Current Transformers (FBCT) observed during Run 1 of the LHC. In the WCT the large magnetic cores commonly used in FBCTs are replaced with small RF transformers distributed around the beam pipe. Rather than directly measuring the beam current, the WCT measures the image current induced by the beam on the walls of the vacuum chamber. The image current is forced to flow through a number of screws which form the single-turn primary windings of the RF transformers. The signals of the secondary windings are combined and the resulting pulse is filtered, amplified and sent to the acquisition system. This paper presents the principle of operation of the WCT and its performance based on laboratory and beam measurements.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEAL02  
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WEPG02 Commissioning of the Bunch-by-Bunch Transverse Feedback System for the TPS Storage Ring kicker, feedback, insertion-device, insertion 612
 
  • Y.-S. Cheng, K.T. Hsu, K.H. Hu, C.H. Huang, C.Y. Liao
    NSRRC, Hsinchu, Taiwan
 
  TPS finish its Phase II commissioning in December of 2015 after installation of two superconducting RF cavities and ten sets of insertion devices in mid-2015. Storage beam current up to 520 mA was achieved. Intensive insertion devices commissioning were performed in March 2016 and delivery beam for beam-line commissioning and perform pilot experiments. One horizontal stripline kicker and two vertical stripline kickers were installed in May 2015. Bunch-by-bunch feedback system were commissioning in late 2015. Commercial available feedback processor was selected for the feedback system integration. Beam property and performance of the feedback system were measured. Results will summary in this report.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG02  
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WEPG19 Conceptual Design of LEReC Fast Machine Protection System laser, gun, electron, dipole 665
 
  • S. Seletskiy, Z. Altinbas, M.R. Costanzo, A.V. Fedotov, D.M. Gassner, L.R. Hammons, J. Hock, P. Inacker, J.P. Jamilkowski, D. Kayran, K. Mernick, T.A. Miller, M.G. Minty, M.C. Paniccia, I. Pinayev, K.S. Smith, P. Thieberger, J.E. Tuozzolo, W. Xu, Z. Zhao
    BNL, Upton, Long Island, New York, USA
 
  The low energy RHIC Electron Cooling (LEReC) accelerator will be running with electron beams of up to 110 kW power with CW operation at 704MHz. Although electron energies are relatively low (< 2.6MeV), at several locations along the LEReC beamline, where the electron beam has small (about 250 um RMS radius) design size, it can potentially hit the vacuum chamber at a normal incident angle. The accelerator must be protected against such a catastrophic scenario by a dedicated machine protection system (MPS). Such an MPS shall be capable of interrupting the beam within a few tens of microseconds. In this paper we describe the current conceptual design of the LEReC MPS.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG19  
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WEPG22 Relation between Signals of the Beam Loss Monitors and Residual Radiation in the J-PARC RCS beam-losses, operation, radiation, proton 673
 
  • M. Yoshimoto, H. Harada, M. Kinsho, K. Yamamoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
 
  The most important issue in realizing such a MW-class high-power routine beam operation is to keep machine activations within a permissible level, that is, to preserve a better hands-on-maintenance environment. Thus, a large fraction of our effort has been concentrated on reducing and managing beam losses. To validate the beam loss optimizations, residual radiation measurement along the ring provide us with further information. By relating signals of the beam loss monitors with the measured distribution of the residual radiation, achievements of the high power beam operation will be described. In this presentation, we will report on the measurement results of residual radiation distribution along the ring together with the relation with the beam loss signals.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG22  
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WEPG35 Design of an Electron Cloud Detector in a Quadrupole Magnet at CesrTA detector, electron, quadrupole, simulation 704
 
  • J.P. Sikora, S.T. Barrett, M.G. Billing, J.A. Crittenden, K.A. Jones, Y. Li, T.I. O'Connell
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, 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.
We have designed a detector that measures the electron cloud density in a quadrupole magnet using two independent techniques. Stripline electrodes collect electrons that would otherwise impact the beam-pipe surface. The striplines are placed behind an array of small holes in the beam-pipe wall in order to shield them from the beam-induced electromagnetic pulse. There are three striplines placed near one of the pole tips so that they cover a roughly 0.43 radian azimuth. The beam-pipe chamber has also been designed so that microwave measurements of the electron cloud density can be performed. Beam position monitor buttons have been included for excitation and reception of microwaves and the chamber has been designed so that the resonant microwaves are confined to be within the 56 cm length of the quadrupole field. This paper provides some details of the design including CST Microwave Studio time domain simulation of the stripline detectors and eigenmode simulation of the resonant chamber. The detector is installed in the Cornell Electron Storage Ring and is part of the test accelerator program for the study of electron cloud using electron and positron beams from 2 to 5 GeV.
 
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG35  
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WEPG37 Nondestructive High-Accuracy Charge Measurement of the Pulses of a 27 MeV Electron Beam from a Linear Accelerator linac, electron, radiation, monitoring 708
 
  • A. Schüller, J. Illemann, R.-P. Kapsch, C. Makowski, F. Renner
    PTB, Braunschweig, Germany
 
  This work presents a description of measuring devices and procedures in order to enable the nondestructive (non-intercepting) absolute measurement of the charge of individual beam pulses (macro-pulses) from an electron linear accelerator with high accuracy, i.e. with a measurement uncertainty <0.1%. In particular, we demonstrate the readout and calibration of a Bergoz integrating current transformer which is frequently applied at many different types of accelerators as a beam intensity monitor. The current transformer signal is calibrated against a custom-made compact Faraday cup with a high degree of collection efficiency for electron beams in the energy range of 6 MeV to 50 MeV (99.2 % at 27 MeV), which is well known from measurements and Monte Carlo calculations.  
poster icon Poster WEPG37 [1.513 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG37  
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WEPG43 A Procedure for the Characterization of Corrector Magnets storage-ring, electron, controls, feedback 728
 
  • S. Gayadeen, M.J. Furseman, G. Rehm
    DLS, Oxfordshire, United Kingdom
 
  At Diamond Light source, the main assumption for the Fast Orbit Feedback (FOFB) controller design is that the corrector magnets all have the same dynamic response. In this paper, a procedure to measure the frequency responses of the corrector magnets on the Diamond Storage Ring is presented and the magnet responses are measured and compared in order to assess whether this assumption is valid. The measurements are made by exciting a single corrector magnet with a sinusoidal input and measuring the resulting sinusoidal movement on the electron beam using electron Beam Position Monitors (eBPMs). The input excitation is varied from 10 Hz to 5 kHz using a 10 mA sine wave. The amplitude ratio and the phase difference between the input excitation and the beam position excitation are determined for each input frequency and the procedure is repeated for several magnets. Variations in both gain and phase across magnets are discussed in this paper and the effect of such variations on the performance of the FOFB controller performance is determined.  
poster icon Poster WEPG43 [1.137 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG43  
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WEPG48 A THz Driven Transverse Deflector for Femtosecond Longitudinal Profile Diagnostics electron, laser, diagnostics, acceleration 748
 
  • S.P. Jamison, E.W. Snedden, D.A. Walsh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • M.J. Cliffe, D.M. Graham, D. Lake
    The University of Manchester, The Photon Science Institute, Manchester, United Kingdom
 
  Progress towards a THz-driven transverse deflecting longitudinal profile diagnostic is presented. The deflector is driven with sub-picosecond quasi-single cycle THz fields generated by non-linear optical rectification. To utilize the large deflection field strength of the source for longitudinal diagnostics it is necessary to maintain the single-cycle field profile of the THz pulse throughout the interaction with the relativistic beam. Our scheme allows for the octave spanning bandwidth of the single-cycle pulses to propagate without dispersion at subluminal velocities matched to co-propagating relativistic electrons, by passing the pulse distortion and group-carrier walk-off limitations of dielectric loaded waveguide structure. The phase velocity is readily tuneable, both above and below the speed of light in a vacuum, and single-cycle propagation of deflecting fields at velocities down to 0.77c have been demonstrated.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG48  
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WEPG50 Non-Invasive Bunch Length Diagnostics of Sub-Picosecond Beams detector, pick-up, simulation, real-time 756
 
  • S.V. Kuzikov, A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
  • S.P. Antipov, S.V. Kuzikov
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • S.V. Kuzikov
    UNN, Nizhny Novgorod, Russia
 
  Funding: This work was partially supported by the Russian Scientific Foundation (grant #16-19-10448).
We propose a non-invasive bunch length measurement system based on RF pickup interferometry. A device performs interferometry between two broadband wake signals generated by a single short particle bunch. The mentioned wakes are excited by two consequent small gaps in beam channel. A field pattern formed by interference of the mentioned two coherent wake signals is registered by means of detector arrays placed at outer side of beam channel. The detectors are assumed to be low-cost integrating detectors (pyro-detectors or bolometers) so that integration time is assumed to be much bigger than bunch length. Because RF signals come from gaps to any detector with different time delays which depend on particular detector coordinate, the array allows to substitute measurements in time by measurements in space. Simulations with a 1 ps beam and a set of two 200 micron wide vacuum breaks separated by 0.5 mm were done using CST Particle Studio. These simulations show good accuracy. Moreover, one can recover the detailed temporal structure of the measured pulse using a new developed synthesis procedure.
 
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG50  
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WEPG55 Synchronization of ps Electron Bunches and fs Laser Pulses Using a Plasmonics-Enhanced Large-Area Photoconductive Detector electron, laser, detector, quadrupole 774
 
  • E.J. Curry, M. Jarrahi, P. Musumeci, N.T. Yardimci
    UCLA, Los Angeles, California, USA
  • B.T. Jacobson
    RadiaBeam, Santa Monica, California, USA
 
  Temporal synchronization between short relativistic electron bunches and laser pulses at the ps and sub-ps level is required for accelerator applications like inverse Compton light sources. Photoconductive antennas with THz and sub-THz bandwidth which are gated by fs lasers provide this level of timing resolution. This paper describes the operating principals of the diagnostic along with bench-top experimental results with recently developed plasmonics-enhanced large-area devices. A vacuum chamber with robust electronic noise reduction has been designed for upcoming beam-based experiments.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG55  
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WEPG66 Beam Induced Fluorescence Monitor R&D for the J-PARC Neutrino Beamline proton, radiation, injection, space-charge 799
 
  • M.L. Friend
    KEK, Ibaraki, Japan
  • C. Bronner, M. Hartz
    Kavli IPMU, Kashiwa, Japan
 
  Proton beam monitoring is essential for the J-PARC neutrino beamline, where neutrinos are produced by the collision of 30 GeV protons with a long carbon target. Along with continued upgrades to the J-PARC beam power, from the current 420 kW to 1.3+ MW, there is also a requirement for monitor upgrades. A Beam Induced Fluorescence monitor is under development, which would continuously and non-destructively measure the proton beam profile spill-by-spill by measuring fluorescence light from proton interactions with gas injected into the beamline. Monitor design is constrained by the J-PARC neutrino beamline configuration, where a major challenge will be getting sufficient signal to precisely reconstruct the proton beam profile. R&D for a pulsed gas injection system is under way, where injected gas uniformity and vacuum pump lifetime are main concerns. Design of a light detection system is also under way, where light transport away from the high radiation environment near the proton beamline, as well as fast detection down to very low light levels, are essential.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG66  
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