Keyword: injection
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MOAL03 Beam Commissioning of SuperKEKB Rings at Phase 1 feedback, operation, detector, damping 6
  • M. Tobiyama, M. Arinaga, J.W. Flanagan, H. Fukuma, H. Ikeda, H. Ishii, K. Mori, E. Mulyani, M. Tejima
    KEK, Ibaraki, Japan
  • G. Bonvicini
    Wayne State University, Detroit, Michigan, USA
  • E. Mulyani
    Sokendai, Ibaraki, Japan
  • G.S. Varner
    University of Hawaii, Honolulu,, USA
  The Phase 1 commissioning of SuperKEKB rings with-out superconducting final focus magnets or Belle-II de-tector began in Feb., 2016. A total of 1010 mA (LER) and 870 mA (HER) stored beam has been achieved close to the design emittance and x-y coupling. Most of the beam diagnostics, including new systems such as gated turn-by-turn monitors and X-ray beam size monitors, have been commissioned with beam and proved to be essential to the success of machine commissioning. The results of the beam commissioning, including the evaluation and diffi-culties of the beam diagnostics are shown.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOAL03  
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MOBL04 LHC Online Chromaticity Measurement - Experience After One Year of Operation operation, controls, feedback, hardware 20
  • K. Fuchsberger, G.H. Hemelsoet
    CERN, Geneva, Switzerland
  Hardware and infrastructural requirements to measure chromaticity in the LHC were available since the beginning. However, the calculation of the chromaticity was mostly made offline. This gap was closed in 2015 by the development of a dedicated application for the LHC control room, which takes the measured data and produces estimates for the chromaticity values immediately online and allows to correct chroma and tune accordingly. This tool proved to be essential during commissioning as well as during every injection-phase of the LHC. It became particularly important during the intensity ramp-up with 25ns where good control of the chromaticity became crucial at injection. This paper describes the concepts and algorithms behind this tool, the experience gained as well as further plans for improvements.  
slides icon Slides MOBL04 [7.414 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOBL04  
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MOPG19 Diamond Monitor Based Beam Loss Measurements in the LHC detector, software, instrumentation, data-acquisition 82
  • C. Xu, B. Dehning, F.S. Domingues Sousa
    CERN, Geneva, Switzerland
  • E. Griesmayer
    CIVIDEC Instrumentation, Wien, Austria
  Two pCVD diamond based beam loss monitors (dBLM) are installed near the primary collimators of the LHC, with a dedicated, commercial readout-system used to acquire their signals. The system is simultaneously able to produce a high sampling rate waveform and provide a real-time beam loss histogram for all bunches in the machine. This paper presents the data measured by the dBLM system during LHC beam operation in 2016.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG19  
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MOPG20 Optimized Beam Loss Monitor System for the ESRF detector, electron, controls, vacuum 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 vacuum, storage-ring, 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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MOPG33 Design of RISP RFQ Cooler Buncher ion, emittance, rfq, extraction 115
  • R. Boussaid, S.A. Kondrashev, Y.H. Park
    IBS, Daejeon, Republic of Korea
  Under RISP project, wide variety of intense rare isotope ion beams will be provided. An EBIS charge breeder has been designed to charge breed these beams. Its optimum operation requires injection of bunched beam with high quality. An RFQ cooler buncher RFQCB is designed to meet these requirements. To meet the EBIS beam requirements, RFQCB should efficiently accept high intensity continuous beams and deliver to the EBIS bunched beams with small emittance (3 '.mm.mrad), low energy spread (< 10 eV) and short bunch width (2-10 μs). A new design concept to be implemented in this RFQCB have been developed, including a novel injection/extraction electrodes geometry, new RF voltages with frequency up to 10 MHz and amplitude up to 10 kV with improved differential pumping system. Simulations have shown the efficient handling of beam intensities which were never handled so far with improved beam quality. An overview of the RFQCB design concept will be presented. Simulated performance of the device and design of different sub-systems will be discussed. Beam parameters will be measured using Faraday cups and emittance meter. The design of these diagnostics tools will be described as well.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG33  
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MOPG48 Optimized Cryogenic Current Comparator for CERN's Low-Energy Antiproton Facilities antiproton, cryogenics, controls, flattop 161
  • M.F. Fernandes, D. Alves, T. Koettig, A. Lees, E. Oponowicz, J. Tan
    CERN, Geneva, Switzerland
  • M.F. Fernandes, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • R. Geithner, R. Neubert, T. Stöhlker
    HIJ, Jena, Germany
  • R. Geithner, R. Neubert, T. Stöhlker
    IOQ, Jena, Germany
  • M. Schwickert
    GSI, Darmstadt, Germany
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  Funding: This project has received funding from the European Unions Seventh Framework Programme for research, technological development and demonstration under grant agreement number 289485.
Non-perturbative measurement of low-intensity charged particle beams is particularly challenging for beam diagnostics due to the low amplitude of the induced electromagnetic fields. In the low-energy Antiproton Decelerator (AD) and the future Extra Low ENergy Antiproton (ELENA) rings at CERN, an absolute measurement of the beam intensity is essential to monitor operational efficiency and provide important calibration data for all AD experiments. Cryogenic Current Comparators (CCC) based on Superconducting QUantum Interference Device (SQUID) have in the past been used for the measurement of beams in the nA range, showing a very good current resolution. However these were unable to provide a measurement of short bunched beams, due to the slew-rate limitation of SQUID devices and their strong susceptibility to external perturbations. Here, we present the measurements and results obtained during 2016 with a CCC system developed for the Antiproton Decelerator, which has been optimized to overcome these earlier limitations in terms of current resolution, system stability, the ability to cope with short bunched beams, and immunity to mechanical vibrations.
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG48  
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MOPG55 Streak Camera Calibration Using RF Switches impedance, synchrotron, cavity, storage-ring 186
  • U. Iriso, M. Alvarez, A.A. Nosych
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  • A. Molas
    UAB, Barcelona, Spain
  The streak camera has been used to measure the bunch length since the ALBA storage ring commissioning in 2011. Previously, we developed an optical calibration system based on the Michelson interferometry. Similar to the work at the DLS*, in this report we show the calibration kit based on the different electrical delays which can be used via rf switches. We compare both calibration systems and we show measurements of the longitudinal impedance obtained with the new calibration.
*L. Bobb, A. Morgan, and G. Rehm, "Streak Camera PSF optimisation and udal sweep calibration for sub-ps bunch length measurements", Proc. of IBIC2015 (Australia)
poster icon Poster MOPG55 [0.848 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG55  
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MOPG57 Temperature and Humidity Drift Characterization of Passive RF Components for a Two-Tone Calibration Method detector, laser, radio-frequency, hardware 194
  • E. Janas, K. Czuba
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
  • E. Janas, U. Mavrič, H. Schlarb
    DESY, Hamburg, Germany
  Femtosecond-level synchronization is required for various systems in modern accelerators especially in fourth generation light sources. In those high precision synchronization systems the phase detection accuracy is crucial. However, synchronization to a low noise electrical source is corrupted by a phase detection error originating in the electrical components and connections due to thermal and humidity-related drifts. In future, we plan to implement calibration methods to mitigate these drifts. Those methods require a calibration signal injection, called second tone, into the system. Intrinsically, the injection circuit remains uncalibrated therefore it needs to be drift-free. We performed drift characterization of a set of RF components, which could serve for implementation of a signal injection circuit, namely selected types of couplers and splitters. We describe the measurement setup and discuss the challenges associated with this kind of measurement. Finally, we provide a qualitative and quantitative evaluation of the measurements results.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG57  
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MOPG74 Design and Performance of Coronagraph for Beam Halo Measurements in the LHC vacuum, 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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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-MOPG74  
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TUAL03 Beam Loss and Abort Diagnostics during SuperKEKB Phase-I Operation hardware, kicker, timing, cavity 282
  • H. Ikeda, J.W. Flanagan, H. Fukuma, T. Furuya, M. Tobiyama
    KEK, Ibaraki, Japan
  Beam commissioning of SuperKEKB Phase-I started in Feb., 2016. In order to protect the hardware components of the accelerator against unstable Ampere class beams, the controlled beam abort system was upgraded. Because of the higher beam intensity and shorter beam lifetime than at the original KEKB, a beam abort monitor system is important for machine tuning and the safety of the components. The system collected the data of all aborts of more than 1000 in this operation period, and we diagnosed not only the hardware performance but the tuning software by analyzing the relations between beam current, loss monitor signals and RF cavity voltages. This paper will give the outline of the monitoring system, and will present typical examples of signal and diagnoses.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUAL03  
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TUPG24 Online Total Ionisation Dosimeter (TID) Monitoring Using Semiconductor Based Radiation Sensors in the ISIS Proton Synchrotron radiation, synchrotron, proton, experiment 379
  • D.M. Harryman, A. Pertica
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  During routine operation, the radiation levels in the ISIS proton synchrotron become high enough to permanently affect systems and electronics. This can potentially cause critical components to fail unexpectedly or denature over time, causing disruption for users of the ISIS facility or a loss of accuracy on a number of systems. To study the long term effects of ionising radiation on ISIS systems and electronics, the total dose received by such components must be recorded. A semiconductor based online Total Ionisation Dosimeter (TID) was developed to do this, using pin diodes and Radiation sensing Field Effect Transistors (RadFETs) to measure the total ionisation dose. Measurements are made by feeding the TIDs with a constant current, with the threshold voltage on each device increasing in relation to the amount of radiation that it has received. This paper will look at preliminary offline results using off the shelf Field Effect Transistors (FETs) and diodes, before discussing the development of the RadFET online monitor and the results it has gathered thus far. Finally the paper will look at future applications and studies that this type of monitor will enable.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG24  
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TUPG35 LEReC Instrumentation Design & Construction electron, ion, gun, emittance 417
  • T.A. Miller, M. Blaskiewicz, K.A. Drees, A.V. Fedotov, W. Fischer, J.M. Fite, D.M. Gassner, R.L. Hulsart, D. Kayran, J. Kewisch, C. Liu, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, P. Oddo, M.C. Paniccia, I. Pinayev, S. Seletskiy, K.S. Smith, Z. Sorrell, P. Thieberger, J.E. Tuozzolo, D. Weiss, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
RHIC will be run at low ion beam center-of-mass energies of 7.7 - 20 GeV/nucleon, much lower than the typical operations at 100 GeV/nucleon. The primary motivation is to explore the existence and location of the critical point on the QCD phase diagram. An electron accelerator is being constructed to provide Low Energy RHIC electron Cooling (LEReC) to cool both the blue & yellow RHIC ion beams by co-propagating a 10 - 50 mA electron beam of 1.6 - 2.6 MeV. This cooling facility will include a 400 keV DC gun, SRF booster cavity and a beam transport with multiple phase adjusting RF cavities to bring the beam to one ring to allow electron-ion co-propagation for ~21 m, then through a 180° U-turn electron transport so that the same electron beam can similarly cool the other counter-rotating ion beam, and finally to a beam dump. The injector commissioning is planned to start in early 2017 and full LEReC commissioning planned to start in early 2018. The instrumentation systems that will be described include current transformers, BPMs, profile monitors, multi-slit and single slit scanning emittance stations, time-of-flight and magnetic energy measurements, and beam halo & loss monitors.
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-TUPG35  
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WEBL02 Beam Size Measurements Using Interferometry at LHC radiation, extraction, synchrotron, undulator 583
  • G. Trad, E. Bravin, A. Goldblatt, S. Mazzoni, F. Roncarolo
    CERN, Geneva, Switzerland
  • T.M. Mitsuhashi
    KEK, Ibaraki, Japan
  During the long LHC shutdown 2013-2014, both the LHC and its injector chain underwent significant upgrades. The most important changes concerned increasing the maximum LHC beam energy from 4TeV to 6.5TeV and reducing the transverse emittance of the beam from the LHC injectors. These upgrades pose challenges to the measurement of the transverse beam size via Synchrotron Radiation (SR) imaging, as the radiation parameters approach the diffraction limit. Optical SR interferometry, widely used in synchrotron light facilities, was considered as an alternative method to measure the 150 'm rms beam size at top energy as it allows measurements below the diffraction limit. A system based on this technique was therefore implemented in the LHC, for the first time on a proton machine. This paper describes the design of the LHC interferometer and its two SR sources (a superconducting undulator at low energy and a bending dipole at high energy), along with the expected performance in terms of beam size measurement as compared to the imaging system. The world's first proton beam interferogram measured at the LHC will be shown and plans to make this an operational monitor will be presented.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEBL02  
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WECL01 Longitudinal Phase Space Diagnostics for Ultrashort Bunches With a Plasma Deflector plasma, laser, electron, wakefield 597
  • I. Dornmair, A.R. Maier
    CFEL, Hamburg, Germany
  • I. Dornmair
    University of Hamburg, Hamburg, Germany
  • K. Flöttmann, B. Marchetti
    DESY, Hamburg, Germany
  • A.R. Maier
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • C.B. Schroeder
    LBNL, Berkeley, California, USA
  We present with simulations a new method to diagnose the longitudinal phase space of ultrashort electron bunches. It harnesses the strong transverse fields of laser-driven wakefields to streak an electron bunch that is injected off-axis with respect to the driver laser. Owed to the short plasma wavelength and the high field amplitude present in a plasma wakefield, a temporal resolution around or below the femtosecond can be achieved with a plasma length of a few millimeters. We will explore the limitations on the time resolution, the calibration, and the influence of error sources such as beam loading and jitters. Amongst the possible applications are experiments aiming at external injection into laser-driven wakefields, or the diagnostics of laser-plasma accelerated beams.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WECL01  
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WEPG10 Phase and Energy Stabilization System at the S-Dalinac electron, controls, linac, cavity 638
  • T. Bahlo, C. Burandt, L.E. Jürgensen, T. Kürzeder, N. Pietralla, J. Wissmann
    TU Darmstadt, Darmstadt, Germany
  • F. Hug
    IKP, Mainz, Germany
  The Superconducting Darmstadt Linear Accelerator S‑DALINAC is a recirculating electron accelerator with a design energy of 130 MeV operating in cw. Before entering the 30 MeV main accelerator the low energetic electron beam passes both a normal-conducting injector beamline preparing the beam's 3 GHz time structure as well as a superconducting 10 MeV injector beamline for preacceleration. Since the superconducting injector accelerates on-crest while the main accelerator accelerates off-crest the beam phase is crucial for the efficiency of the acceleration process and the minimization of the energy spread. Due to thermal drifts of the normal-conducting injector cavities this injection phase varies by about 0.2 degree over a timescale of an hour. In order to compensate for these drifts, a high level phase controller has been implemented. Additionally a low-energy scraper system has been installed between the injector and main linac in order to lock both the phase and the energy spread at the linac entrance. We will present the hardware for the phase controller, the control algorithm and the scraper setup. A report on measurements showing the effect of both systems will be given.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG10  
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WEPG20 An Optical Fibre BLM System at the Australian Synchrotron Light Source booster, storage-ring, synchrotron, electron 669
  • M. Kastriotou, E.B. Holzer, E. Nebot Del Busto
    CERN, Geneva, Switzerland
  • M.J. Boland
    The University of Melbourne, Melbourne, Victoria, Australia
  • M. Kastriotou, E. Nebot Del Busto, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • M. Kastriotou, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  Increasing demands on high energy accelerators are triggering R&D into improved beam loss monitors with a high sensitivity and dynamic range and the potential to efficiently protect the machine over its entire length. Optical fibre beam loss monitors (OBLMs) are based on the detection of Cherenkov radiation from high energy charged particles. Bearing the advantage of covering more than 100m of an accelerator with only one detector and being insensitive to X-rays, OBLMs are ideal for electron machines. The Australian Synchrotron comprises an 100 MeV 15m long linac, an 130m circumference booster synchrotron and a 3 GeV, 216m circumference electron storage ring. The entire facility was successfully covered with four OBLMs. This contribution summarises a variety of measurements performed with OBLMs at the Australian Synchrotron, including beam loss measurements during the full booster and measurements of steady-state losses in the storage ring. Different photosensors, namely Silicon Photo Multipliers (SiPM) and fast Photo Multiplier Tubes (PMTs) have been used and their respective performance limits are discussed.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG20  
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WEPG66 Beam Induced Fluorescence Monitor R&D for the J-PARC Neutrino Beamline proton, radiation, space-charge, vacuum 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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WEPG69 Profile Measurement by the Ionization Profile Monitor with 0.2T Magnet System in J-PARC MR electron, ion, detector, simulation 811
  • K. Satou, H. Kuboki, T. Toyama
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  A nondestructive Ionization Profile Monitor (IPM) is widely used to measure transversal profile. At J-PARC Main Ring (MR), three IPM systems have been used not only to measure emittances but also to correct injection miss matchings. To measure injection 3GeV beam profiles, the high external E field of +50kV/130mm at the maximum is used to guide ionized positive ions to a position sensitive detector; transversal kick force originating from space charge E field of circulating beam is a main error source which deteriorates profile. The strong B field is also used to compensate the kick force. To measure 30GeV bunched beam at the flat top on the fast extraction mode in good resolution, the strong B field of about 0.2T is needed. One set of magnet system, which consists of a C-type and two H-type magnets, were developed and installed in one IPM system. The IPM chamber was inserted between the 2 poles of the C-type magnet. To make the line integral of B field along the beam axis zero, the H-type magnets have the opposite field polarity to that of the C-type magnet and were installed on both sides of the C-type magnet. Details of the magnet system and its first trials will be presented.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-WEPG69  
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THAL02 Recent Developments for Instability Monitoring at the LHC operation, diagnostics, pick-up, network 852
  • T.E. Levens, K. Łasocha, T. Lefèvre
    CERN, Geneva, Switzerland
  A limiting factor on the maximum beam intensity that can be stored in the Large Hadron Collider (LHC) is the growth of transverse beam instabilities. Understanding and mitigating these effects requires a good knowledge of the beam parameters during the instability in order to identify the cause and provide the necessary corrections. This paper presents the suite of beam diagnostics that have been put into operation to monitor these beam instabilities and the development of a trigger system to allow measurements to be made synchronously with multiple instruments as soon as any instability is detected.  
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DOI • reference for this paper ※ DOI:10.18429/JACoW-IBIC2016-THAL02  
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