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MOBO04 Characterization and First Beam Loss Detection with One ESS-nBLM System Detector neutron, detector, linac, proton 28
 
  • L. Segui, H. Alves, S. Aune, J. Beltramelli, Q. Bertrand, M. Combet, M. Kebbiri, Ph. Legou, O. Maillard, A. Marcel, T. Papaevangelou
    CEA-IRFU, Gif-sur-Yvette, France
  • A. Dano-Daguze, D. Desforge, F. Gougnaud, T.J. Joannem, C. Lahonde-Hamdoun, P. Le Bourlout, Y. Mariette, J. Marroncle, V. Nadot, G. Tsiledakis
    CEA-DRF-IRFU, France
  • I. Dolenc Kittelmann, T.J. Shea
    ESS, Lund, Sweden
 
  The monitoring of losses is crucial in any accelerator. In the new high intensity hadron facilities even low energy beam can damage or activate the materials so the detection of small losses in this region is very important. A new type of neutron beam loss monitor has been developed specifically targeting this region, where only neutrons and photons can be produced and where typical BLM, based on charged particle detection, could not be appropriate because of the photon background due to the RF cavities. The BLM proposed is based on gaseous Micromegas detectors, designed to be sensitive to fast neutrons and with little sensitivity to photons. Development of the detectors presented here has been done to fulfil the requirements of ESS and they will be part of the ESS-BI systems. The detector has been presented in previous editions of the conference. Here we focus on the neutron/gamma rejection with the final FEE and in the first operation of one of the modules in a beam during the commissioning of LINAC4 (CERN) with the detection of provoked losses and their clear separation from RF gammas. The ESS-nBLM system is presented in this conference in a separate contribution.  
slides icon Slides MOBO04 [7.609 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOBO04  
About • paper received ※ 05 September 2019       paper accepted ※ 09 September 2019       issue date ※ 10 November 2019  
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MOCO04 Overview of Bunch-Resolved Diagnostics for the Future BESSY VSR Electron-Storage Ring diagnostics, electron, timing, storage-ring 49
 
  • G. Schiwietz, J.G. Hwang, M. Koopmans, M. Ries
    HZB, Berlin, Germany
 
  The upgrade of the BESSY II light source in Berlin towards the Variable pulse-length Storage-Ring BESSY VSR will lead to a complex fill pattern. This involves co-existing electron bunches with significant variations of bunch-length, bunch charge as well as charge density. Among many other boundary conditions, this calls for bunch resolved measurements with sub-ps time resolution and micrometer spatial resolution. Currently, we are constructing a diagnostic platform connected to three new dipole beamlines for visible light as well as THz measurements. The mid-term aim is a 24/7 use of beam-diagnostic tools and the development of advanced methods for specific purposes. Recently, we have set-up a sub-ps streak camera* and we are investigating other innovative methods for bunch-length** as well as lateral size determination using visible light*** at the first of our new diagnostic dipole beamlines. Preliminary results as well as our concepts for achieving high sensitivity, good signal-to-noise ratio and time resolution will be presented and discussed at the conference.
* G.Schiwietz et al., J.Phys.:Conf. Series 1067, 072005 (2018)
** T.Mitsuhashi, M.Tadano, Proc. of EPAC’02, Paris, France, p. 1936
*** J.Breunlin et al., NIM- A803, pp.55 (2015) &refs. therein
 
slides icon Slides MOCO04 [10.924 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOCO04  
About • paper received ※ 04 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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MOPP006 Commissioning of the Beam Loss Monitoring system for the HADES beam-line at GSI detector, proton, simulation, heavy-ion 73
 
  • P. Boutachkov, S. Damjanovic, M. Sapinski, B. Walasek-Höhne
    GSI, Darmstadt, Germany
 
  The High Acceptance Di-Electron Spectrometer experiments at GSI (HADES) require high-intensity heavy ion beams. Monitoring and minimization of the beam losses are critical for the operation at the desired beam intensities. FAIR-type Beam Loss Monitor (BLM) system based on sixteen plastic scintillator detectors is installed along the beam line from the SIS-18 synchrotron to the experiment location. The detectors are used in counting mode, with maximum counting rate of order of 20 MHz. The system has been commissioned during the 2018 beam time. Details on the detector setup, its calibration procedure and how it can be used for quantitative beam loss determination are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP006  
About • paper received ※ 04 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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MOPP007 Versatile Beamline Cryostat for the Cryogenic Current Comparator (CCC) for FAIR cryogenics, resonance, simulation, vacuum 77
 
  • D.M. Haider, F. Kurian, M. Schwickert, T. Sieber, T. Stöhlker, F. Ucar
    GSI, Darmstadt, Germany
  • H. De Gersem, N. Marsic, W.F.O. Müller
    TEMF, TU Darmstadt, Darmstadt, Germany
  • J. Golm
    FSU Jena, Jena, Germany
  • J. Golm, T. Koettig
    CERN, Meyrin, Switzerland
  • M. Schmelz, R. Stolz, V. Zakosarenko
    IPHT, Jena, Germany
  • T. Stöhlker
    IOQ, Jena, Germany
  • T. Stöhlker, V. Tympel
    HIJ, Jena, Germany
  • V. Zakosarenko
    Supracon AG, Jena, Germany
 
  Funding: Work supported by AVA - Accelerators Validating Antimatter the EU H2020 Marie-Curie Action No. 721559 and by the BMBF under contract No. 05P15SJRBA and 5P18SJRB1.
The Cryogenic Current Comparator (CCC) extends the measurement range of traditional non-destructive current monitors used in accelerator beamlines down to a few nano-amperes of direct beam current. This is achieved by a cryogenic environment of liquid helium around the beamline, in which the beam’s magnetic field is measured with a Superconducting Quantum Interference Device (SQUID), which is itself enclosed in a superconducting shielding structure. For this purpose, a versatile UHV-beamline cryostat was designed for the CCCs at FAIR and is currently in production. It is built for long-term autonomous operation with a closed helium re-liquefaction cycle and with good access to all inner components. The design is supported by simulations of the cryostat’s mechanical eigenmodes to minimize the excitation by vibrations in an accelerator environment. A prototype at GSI has demonstrated the self-contained cryogenic operation in combination with a 15 l/day re-liquefier. The cryostat will be used in CRYRING to compare the FAIR-CCC-X with newly developed CCC-types for 150 mm beamlines. Both which will supply a nA current reading during commissioning and for the experiments.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP007  
About • paper received ※ 04 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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MOPP010 Design and Properties of a New DCCT Chamber for the PF-Ring at KEK simulation, impedance, HOM, cavity 90
 
  • R. Takai, T. Honda, T. Nogami, T. Obina, Y. Tanimoto
    KEK, Ibaraki, Japan
 
  A DC current transformer (DCCT) for the PF-ring was renewed during the 2018 summer shutdown. A vacuum chamber for the new DCCT was designed based on a circular duct with an inner diameter of 100 mm and has a structure housing a toroidal core inside of electromagnetic shields. The geometry of the ceramic break for interrupting the wall current flow was optimized using a three-dimensional electromagnetic field simulator, and the break was fabricated considering some technical limitations. Both ends of the ceramic break were short-circuited in a high-frequency manner by a sheet-like capacitive structure to suppress the radiation of unneeded higher-order modes (HOMs) into the core housing. The ceramic break is also equipped with water-cooling pipes on metal sleeves brazed to the both ends to efficiently remove the heat generated by HOMs. The new DCCT chamber has been used already in user operation without any problems. A temperature rise near the ceramic break is still approximately six degrees Celsius, even when a 50-mA isolated bunch is stored.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP010  
About • paper received ※ 04 September 2019       paper accepted ※ 07 September 2019       issue date ※ 10 November 2019  
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MOPP011 A Dual Functional Current Monitor for Stripping Efficiency Measurement in CSNS electronics, electron, proton, injection 95
 
  • W.L. Huang, F. Li, R.Y. Qiu, A.X. Wang
    IHEP CSNS, Guangdong Province, People’s Republic of China
  • M.Y. Huang, M.Y. Liu, T.G. Xu
    IHEP, Beijing, People’s Republic of China
 
  Funding: This work is supported by National Natural Science Fund(No.11605214).
China Spallation Neutron Source (CSNS), the biggest platform for neutron scattering research in China, has been finished construction and already in user operation stage by the end of 2017. During the multi-turn charge-exchange injection, H stripping by a carbon primary stripper foil (100 ’g/cm2) and a secondary stripper foil (200 ’g/cm2) is adopted for this high intensity proton synchrotron. In order to evaluate the stripping efficiency and the foil aging, a dual-function low noise current transformer and corresponding electronics are designed to measure the ultra-low intensity of H and H0, which are not stripped completely by the 1st foil but totally stripped charge changing to H+ and delivered to the IN-DUMP. The self-designed CT sensors made of domestic nanocrystalline toroids, the noise analysis and elimination, measurement results and further improvement proposals are presented in this paper.
 
poster icon Poster MOPP011 [3.186 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP011  
About • paper received ※ 04 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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MOPP014 Design of the ESS MEBT Faraday Cup electron, radiation, MEBT, proton 105
 
  • A. Rodríguez Páramo, I. Bustinduy, I. Mazkiaran, R. Miracoli, V. Toyos, S. Varnasseri, D. de Cos, C. de la Cruz
    ESS Bilbao, Zamudio, Spain
  • E.M. Donegani, J.P.S. Martins
    ESS, Lund, Sweden
 
  The European Spallation Source (ESS) is currently under construction and the Medium Energy Beam Transfer (MEBT) is developed by ESS-Bilbao as an in-kind contribution. In the MEBT a set of diagnostics is included for beam characterization, among them the MEBT Faraday Cup is used to measure beam current and as a beam stopper for the commissioning modes. The main challenges for the design and manufacturing of the Faraday Cup are the high irradiation loads and the necessity of a compact design due to the space constraints in the MEBT. We describe the design of the FC, characterized by a graphite collector, required to withstand irradiation, and a repeller for suppression of secondary electrons. For the operation of the Faraday Cup acquisition electronics and control system are developed, all systems have been integrated in the ESS-Bilbao ECR ion source to test operation under beam conditions. In this work, we discuss the design of the Faraday Cup, the results of the tests and how they agree with the expected performance of the Faraday Cup.  
poster icon Poster MOPP014 [1.786 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP014  
About • paper received ※ 02 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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MOPP019 Development and Evaluation of an Alternative Sensor Lifetime Enhancement Technique Used with the Online-Radiation-Monitoring System (DosiMon) at the European XFEL at DESY, Hamburg radiation, FEL, electron, controls 121
 
  • F. Schmidt-Föhre, S. Arab, D. Nölle, R. Susen
    DESY, Hamburg, Germany
 
  The European XFEL (E-XFEL), that started operation in September 2017 at the DESY/XFEL site in Hamburg/Germany uses a single-tunnel concept, forcing all frontend machine devices and electronics to be located inside the accelerator tunnel. Electro-magnetic showers, mainly produced by gun dark-current, RF cavity field-emission and beam-losses expose these devices to damaging irradiation. The new Online-Radiation-Monitoring-System (DosiMon) is mainly used for surveillance of radiation sensitive permanent magnet structures, diagnostic devices and rack-housed electronics. The integrated dose from Gamma- and optional future Neutron-radiation measurements can be monitored online by the DosiMon system. Safety limits ensure the correct function of monitored devices, provided by lifecycle estimations as measures for on time part exchange, to prevent significant radiation damage. A first expansion state currently enables more than 500 gamma measuring points. The development of a new sensor lifetime enhancement technique for the utilized RadFet sensors is presented together with corresponding evaluation measurements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP019  
About • paper received ※ 04 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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MOPP028 Longitudinal Bunch-by-Bunch Feedback Systems for SuperKEKB LER feedback, kicker, timing, damping 158
 
  • M. Tobiyama, J.W. Flanagan, T. Kobayashi, S. Terui
    KEK, Ibaraki, Japan
  • J.D. Fox
    Stanford University, Stanford, California, USA
 
  Longitudinal bunch-by-bunch feedback systems to suppress coupled bunch instabilities with minimum bunch spacing of 2 ns have been constructed in SuperKEKB LER. Through the grow-damp and excite-damp experiments with several filling patterns and the transient-domain analysis of unstable modes, the behaviors of possible impedance sources have been evaluated. The measured performance of the system, together with the performance of the related systems such as slow phase feedback to the reference RF clock are reported.  
poster icon Poster MOPP028 [0.519 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP028  
About • paper received ※ 03 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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MOPP030 Preliminary Test of XBPM Local Feedback in TPS feedback, electron, photon, synchrotron 162
 
  • P.C. Chiu, J.-Y. Chuang, K.T. Hsu, K.H. Hu, C.H. Huang
    NSRRC, Hsinchu, Taiwan
 
  TPS is 3-GeV synchrotron light source which have opened for public users since September 2016 and now offers 400 mA top-up mode operation. The requirements of the long term orbit stability have been gradually more and more stringent. The report investigates the long-term orbit stability improved by applying local XBPM feedback.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP030  
About • paper received ※ 02 September 2019       paper accepted ※ 09 September 2019       issue date ※ 10 November 2019  
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MOPP045 MAX IV Operations - Diagnostic Tools and Lessons Learned storage-ring, synchrotron, status, injection 210
 
  • B. Meirose, V. Abelin, B.E. Bolling, M. Brandin, R. Høier, A. Johansson, P. Lilja, J.S. Lundquist, S. Molloy, F. Persson, J.E. Petersson, R. Svärd
    MAX IV Laboratory, Lund University, Lund, Sweden
 
  In this contribution, I present some of the new beam diagnostic and monitoring tools developed by the MAX IV Operations Group. In particular, new BPM and accelerator tunes visualization tools and other simple but useful applications we have developed, such as our RF System Monitor, are presented. I also briefly share our experience with the development of audible alarms, which help operators monitor various parameters of the machine and explain how the implementation of all these tools have improved accelerator operations at MAX IV.  
poster icon Poster MOPP045 [2.879 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP045  
About • paper received ※ 04 September 2019       paper accepted ※ 07 September 2019       issue date ※ 10 November 2019  
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TUBO02 FERMI-PSI Collaboration on Nano-Fabricated Wire-Scanners With Sub-Micrometer Resolution: Developments and Measurements. FEL, electron, experiment, emittance 243
 
  • G.L. Orlandi, S. Borrelli, Ch. David, E. Ferrari, V. Guzenko, B. Hermann, O. Huerzeler, R. Ischebeck, C. Lombosi, C. Ozkan Loch, E. Prat
    PSI, Villigen PSI, Switzerland
  • N. Cefarin, S. Dal Zilio, M. Lazzarino
    IOM-CNR, Trieste, Italy
  • M. Ferianis, G. Penco, M. Veronese
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
 
  Wire-scanners with micrometer resolution are in operation at SwissFEL and FERMI for measurements of the beam emittance and for beam profile monitoring (*,**). In addition, both laboratories are developing and testing innovative nano-fabricated wire-scanners capable of providing sub-micrometer resolution and being quasi non-destructive to the beam. Nano-fabricated wire-scanners with a free-standing design (***) and a sub-micrometer resolution (****) has been already successfully tested. In the present work, innovative nano-fabricated wire-scanners joining both features of a free-standing design and sub-micrometer resolution are presented. Experimental tests carried out at SwissFEL demonstrated the capability of such innovative wire-scanner solutions to resolve transverse profiles of the electron beams with a size of 400-500 nm without incurring in any resolution limit constraint and with a minimal beam perturbation. An overview on current status and results along with future developments of these nano-fabricated wire-scanners are here presented.
(*)G.L.Orlandi et al. PRAB 19, 092802 (2016).
(**)M.Veronese et al.this Conference.
(***)M.Veronese et al.NIM-A 891, 32-36, (2018)
(****)S.Borrelli et al. Comm. Phys.-Nature, 1, 52 (2018).
 
slides icon Slides TUBO02 [10.551 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUBO02  
About • paper received ※ 04 September 2019       paper accepted ※ 07 September 2019       issue date ※ 10 November 2019  
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TUPP010 A Fast Wire Scanner System for the European XFEL FEL, timing, detector, optics 299
 
  • T. Lensch, B. Beutner, T. Wamsat
    DESY, Hamburg, Germany
 
  The European-XFEL is an X-ray Free Electron Laser facility located in Hamburg (Germany). The 17.5 GeV superconducting accelerator will provide photons simultaneously to several user stations. Currently 14 Wire Scanner stations are used to image transverse beam profiles in the high energy sections. These scanners provide a slow scan mode for beam halo studies and beam optics matching. When operating with long bunch trains (>100 bunches) fast scans will be used to measure beam sizes in an almost non-destructive manner. This paper briefly describes the wire scanner setup and focusses on the fast scan concept and first measurements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP010  
About • paper received ※ 04 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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TUPP011 Observation of Scintillators Charging Effects at the European XFEL FEL, electron, diagnostics, site 303
 
  • A.I. Novokshonov, B. Beutner, G. Kube
    DESY, Hamburg, Germany
  • S.A. Strokov
    TPU, Tomsk, Russia
 
  Scintillating screens are widely used for beam profile diagnostics at various kinds of particle accelerators. At modern linac based electron machines with ultrashort bunches as the European XFEL in Hamburg (Germany), scintillators help to overcome the limitation of standard OTR based monitors imposed by the emission of coherent radiation. The XFEL injector section is equipped with four off-axis screens allowing to perform online beam profile diagnostics, i.e. a single bunch out of a bunch train is kicked onto the screen and the profile is analyzed. However, during user operation a decrease of the SASE level was observed in cases that one of the of-axis screens was used. The observation is explained by charging of the scintillator screen: each deflected bunch hitting the screens causes ionization and charging of the screen. The scintillator as good insulator keeps the charge for some time such that the non-deflected part of the bunch-train feels their Coulomb force and experiences a kick, resulting in a drop of the SASE level. This report summarizes the observations at the European XFEL and introduces a simple model for quantification of this effect.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP011  
About • paper received ※ 04 September 2019       paper accepted ※ 07 September 2019       issue date ※ 10 November 2019  
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TUPP014 New Combined Function Wire Scanner-Screen Station for the High Resolution Transverse Profile Measurements at FERMI electron, FEL, vacuum, laser 317
 
  • M. Veronese, A. Abrami, M. Bossi, M. Ferianis, S. Grulja, G. Penco, M. Tudor
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
 
  We present the upgrade of the transverse profile diagnostics at the end of the FERMI Linac with a new high resolution instrumentation with the aim of improving the accuracy of the measurement of the twiss parameters and of the emittance. A scintillating screen, has been adopted instead of OTR screen due to known COTR issues. We used the same COTR suppression geometry that we had already implemented on our intra undulator screens and YAG:Ce as scintillating material. Screen based transverse profile diagnostics provide single shot measurements with a typical resolution of the order of tens of microns mainly due to refraction effects, geometry and other physical material properties. To extend the resolution to the micron level needed in case of low charge operation, we have equipped the same vacuum chamber with a wire scanner housing 10 micron tungsten wires. This paper describes the design and the first operational experience with the new device and discusses advantages as well as limitations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP014  
About • paper received ※ 04 September 2019       paper accepted ※ 09 September 2019       issue date ※ 10 November 2019  
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TUPP018 Synchrotron Radiation Monitor for SuperKEKB Damping Ring in Phase-III Operation damping, injection, positron, MMI 331
 
  • H. Ikeda, J.W. Flanagan, H. Fukuma, H. Sugimoto, M. Tobiyama
    KEK, Ibaraki, Japan
 
  The SuperKEKB damping ring (DR) commissioned in March 2019, before main ring (MR) Phase-III operation. The design luminosity of SuperKEKB is 40 times that of KEKB with high current and low emittance. We constructed the DR in order to deliver a low-emittance positron beam. A synchrotron radiation monitor (SRM) was installed for beam diagnostics at the DR. Streak camera and gated camera were used for measurement of the damping time and the beam size. This paper shows the design of DR SRM and the result of the measurement.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP018  
About • paper received ※ 04 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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TUPP020 Development of a Gated IPM System for J-PARC MR electron, detector, GUI, impedance 338
 
  • K. Satou
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
 
  In the Main Ring (MR) of Japan Proton Accelerator Research Complex (J-PARC), a residual-gas ionization profile monitor (IPM) is used to measure bunched beam profiles. After injection, the beam widths of the first ~20 bunched beams are analysed to correct the Quadruple oscillation. While only a few dozen profiles are required for this correction, the present IPM auto-matically measures all bunched beams, more than 2·106 bunches from injection to the extraction, because the present IPM operates using DC. This system is unde-sirable due to the limited lifetime of the Micro Channel Plate (MCP) detector; the more particles the MCP senses, the more it loses gain flatness and thus lifetime. To improve this situation, a gated IPM system has been developed, in which the High Voltage (HV) is operated in pulse mode. Results of performance analysis of a new HV power supply, improvement of the electrodes, and particle-tracking simulation considering the space-charge-electric field of the bunched beam are de-scribed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP020  
About • paper received ※ 04 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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TUPP021 Development of 16 Electrodes Beam-size Monitors for J-PARC MR emittance, quadrupole, proton, impedance 342
 
  • M. Tajima, T. Nakaya
    Kyoto University, Kyoto, Japan
  • T. Koseki, T. Toyama
    KEK, Tokai, Ibaraki, Japan
 
  For J-PARC, 16 electrodes beam-monitors are developed. It is possible to measure the transverse moments of beams from the induced voltages. A beam size is calculated from these in two locations with different values of beta functions. Beam-monitors such as a Flying Wire Monitor and an Ionization Profile Monitor (IPM) are already installed. However, the two monitors have issues in measuring higher intensity beams. The former is that the wire gets easily burned out and the latter is that there is a sign of the saturation by a space charge effect. Therefore, these aim at measuring the sizes of high intensity proton beams up to 4.2·10+13 protons/bunch, which corresponds to 1.3 MW in 1.16 s cycle operation of the MR. Furthermore, with high accuracy measurements, the injection mismatch from the RCS is to be decreased. In the beam test in February 2019, the signal-noise ratio (SNR) of this monitor in bunch-by-bunch measurements was nearly 40 dB and lower than the SNR > 50 dB which is comparable to IPM. To improve the SNR, we developed new LPFs for anti-aliasing and improved signal processing. In addition, the second monitor will be installed in August 2019 and tested with beams in November.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP021  
About • paper received ※ 04 September 2019       paper accepted ※ 09 September 2019       issue date ※ 10 November 2019  
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TUPP028 Double-Wire Vibrating Wire Monitor (DW-VWM) for Beam Halo Monitoring in High-intensity Accelerators vacuum, experiment, laser, electron 368
 
  • D.H. Kwak, M. Chung
    UNIST, Ulsan, Republic of Korea
  • S.G. Arutunian, A.V. Margaryan
    ANSL, Yerevan, Armenia
  • G.S. Harutyunyan, E.G. Lazareva
    YSU, Yerevan, Armenia
 
  Funding: This work was partly supported by the National Research Foundation of Korea (Grants No. 2017M1A7A1A02016413).
Double-Wire Vibrating Wire Monitor (DW-VWM) has been designed and manufactured to monitor the beam halo in high-intensity accelerators. Compared with the previous VWM, we increase the ratio between the aperture and wire length by using strong 5 mm x 5 mm Samarium-Cobalt magnets. In addition, we install two stainless steel vibrating wires on the same frame. The first wire is placed in the beam halo region for measurements, and the second wire, which is separated from the beam by a screen, is used to subtract background signal caused by ambient temperature shifts. The new electronics of the DW-VWM consist of two main boards: auto-generation unit which is placed near the VWM, and the frequency measurement unit which is placed in the control room (100 m distance operation was tested). Typical frequency of the VWM (at start tension about 0.7 of tensile strength) is about 8000 Hz. The temperature sensitivity is about 110 Hz/K with 0.2 mK Hz resolution. The VWM was tested in vacuum tank and the frequency corresponding to each vacuum level was analyzed. The process of oscillation excitation at different levels of vacuum was also investigated.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP028  
About • paper received ※ 04 September 2019       paper accepted ※ 11 September 2019       issue date ※ 10 November 2019  
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TUPP033 Laboratory and Beam Based Studies for Assessing the Performance of the New Fast Wire Scanners for the CERN Injector Complex controls, laser, feedback, emittance 387
 
  • J. Emery, P. Andersson, W. Andreazza, J.M. Fernandez Ochoa, A. Goldblatt, D. Gudkov, F. Roncarolo, J.L. Sirvent, J. Tassan-Viol, R. Veness
    CERN, Geneva, Switzerland
 
  At CERN, fast beam wire scanners serve as reference transverse profile monitors in all synchrotrons. As part of the LHC Injector Upgrade project, a new generation of scanners has been designed to improve system reliability, precision and accuracy in view of higher brightness beams. This paper will discuss the performance achieved during both laboratory calibration and prototype testing with beam. The beam measurements performed in 2018 demonstrated excellent system reliability and reproducibility, while calibration in the laboratory showed that an accuracy below 10 um can be achieved on the wire position determination.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP033  
About • paper received ※ 04 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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TUPP043 Fast and Robust Wire Scanners with Novel Materials for Profiling High Intensity Beams controls, detector, diagnostics, laser 433
 
  • G. Andonian, T.J. Campese, A. Laurich, M. Ruelas
    RadiaBeam, Marina del Rey, California, USA
  • G. Andonian, J.K. Penney
    UCLA, Los Angeles, California, USA
  • J. Gubeli, K. Jordan, J. Yan
    JLab, Newport News, Virginia, USA
  • C.F. Huff, L.R. Scammell, R.R. Whitney
    BNNT, LLC, Newport News, USA
 
  Wire scanners are robust devices for beam characterization in accelerator facilities. However, prolonged usage with intense particle beams leads to wire damage, requiring replacement and beam diagnostic downtime. The fast, robust wire scanner was recently designed and engineered with swappable and modular wire cards, that can accommodate different wire materials under tension. Testing is currently underway at the Jefferson Laboratory (JLab) Low Energy Recirculating Facility. During the course of the diagnostic development and commissioning, we will test Tungsten, Carbon, and boron-nitride nanotube in wire form. The latter is particularly relevant as early results on the material show that it has very high thermal thresholds and may withstand the high-power of the beam during regular operations. This paper will report on the system design and engineering, and preliminary results with operation on the beamline.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP043  
About • paper received ※ 05 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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WECO03 Tune Computation via Model Fitting to Swept Machine Response Measurement synchrotron, feedback, betatron, resonance 482
 
  • M.G. Abbott, G. Rehm
    DLS, Oxfordshire, United Kingdom
 
  At Diamond Light Source we compute the horizontal and vertical tunes by fitting a simple multi-pole resonator model to the measured electron beam frequency response. The transverse (and longitudinal) tune response is measured by sweeping an excitation across the range of possible tune frequencies and synchronously measuring the IQ response. The multi-pole resonator model is a good fit to the measured behaviour, but the fitting process is surprisingly challenging. Problems include noisy measurements, very complex beam responses in the presence of increasing chromaticity, poor data when the beam is close to instability, and a number of challenges with the stability of the algorithm. The tune fitting algorithm now in use at Diamond has been developed and refined over many years. It is finally stable enough to work reliably throughout most beam operating conditions. The algorithm involves alternating peak finding and non-linear fitting, with a fairly naive mathematical approach; the main focus is on providing reliable results.  
slides icon Slides WECO03 [1.059 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WECO03  
About • paper received ※ 04 September 2019       paper accepted ※ 09 September 2019       issue date ※ 10 November 2019  
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WEPP003 A new button-type beam position monitor for BESSY II and BESSY VSR impedance, vacuum, storage-ring, synchrotron 500
 
  • J.G. Hwang, V. Dürr, F. Falkenstern, M. Ries, A. Schälicke, G. Schiwietz, D. Wolk
    HZB, Berlin, Germany
 
  Funding: This work was supported by the German Bundesministerium für Bildung und Forschung, Land Berlin and grants of Helmholtz Association.
The future BESSY VSR system involves more than one order-of-magnitude differences in the total charge of adjacent short and long bunches within the bunch train. Thus, any signal ringing beyond a nanosecond in time will cause a misreading of beam position and current, specifically for low bunch charges. This calls for improved performance for the bunch-selective operation of the beam-position-monitor (BPM) system. We report on the corresponding design and fabrication of a new button BPM with advanced features, such as impedance matching inside the button as well as optimization of insulator material, button size, and position, for reduced crosstalk between buttons.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP003  
About • paper received ※ 04 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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WEPP004 Concept of a Beam Diagnostics System for the Multi-Turn ERL Operation at the S-DALINAC cavity, linac, recirculation, impedance 505
 
  • M. Dutine, M. Arnold, T. Bahlo, R. Grewe, L.E. Jürgensen, N. Pietralla, F. Schließmann, M. Steinhorst
    TU Darmstadt, Darmstadt, Germany
 
  Funding: Work supported by BMBF through grant No. 05H18RDRB2 and DFG through GRK 2128.
The S-DALINAC* is a thrice-recirculating linear electron accelerator operating in cw-mode at a frequency of 3 GHz. A path-length adjustment system in the second recirculation beam line allows to shift the beam phase by 360° and thus to operate in ERL mode. For the multi-turn ERL operation, the beam will be accelerated twice and subsequently decelerated twice again (not demonstrated yet). For this mode, it is necessary to develop a nondestructive beam diagnostics system in order to measure the beam position, phase and beam current of both, the accelerated and the decelerated beam, simultaneously in the same beamline. A particular challenge will be the operation at low beam currents of 100 nA, which corresponds to bunch charges of about 30 aC. The conceptional study of a 6 GHz resonant cavity beam position monitor will be presented together with alternative solutions.
* N. Pietralla, Nuclear Physics News, Vol. 28, No. 2, 4 (2018)
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP004  
About • paper received ※ 03 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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WEPP006 Operational Performance of New Detection Electronics for Stripline-Type Beam Position Monitors at the SuperKEKB Injector Linac linac, quadrupole, emittance, electron 514
 
  • F. Miyahara, K. Furukawa, M. Satoh, Y. Seimiya, T. Suwada
    KEK, Ibaraki, Japan
 
  SuperKEKB injector linac delivers four different beam modes modulated pulse by pulse at 50 Hz, which have 100-times different beam charges, and a pulse may contain two bunches only 96-ns apart. Required low-emittance beams for SuperKEKB rings would need precise beam orbit controls in order to suppress the transverse wakefield in the accelerating structures. A new detection electronics with a wide dynamic range of 40 dB with a high resolution based on a 180-MHz narrow-band detection technique for stripline-type beam position monitors (BPMs) has been developed for the SuperKEKB injector linac. While such measurement condition is challenging, a position resolution of 3 micrometer in one standard deviation was successfully achieved with beam-based tests. The self-calibration system is also installed in order to compensate gain drifts for each input channel with an accuracy down to 0.1%, by using test pulses going through stripline heads between 50-Hz beam pulses. The design concept of the new detection electronics is described in detail, as well as operational performance of synchronized measurement with 100 BPMs for injection beams to four electron/positron storage rings.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP006  
About • paper received ※ 09 September 2019       paper accepted ※ 11 September 2019       issue date ※ 10 November 2019  
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WEPP035 Using Tune Measurement Systems Based on Diode Detectors for Quadrupolar Beam Oscillation Analysis in the Frequency Domain injection, detector, betatron, pick-up 609
 
  • M. Gąsior, T.E. Levens
    CERN, Geneva, Switzerland
 
  Requirements for diagnostics of injection matching and beam space charge effects have driven studies at CERN using high sensitivity tune measurement systems based on diode detectors for the observation of quadrupolar beam oscillations in the frequency domain. This has led to an extension of such tune systems to include a channel optimised for quadrupolar oscillation measurements. This paper presents the principles of such measurements, the developed hardware and example measurements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP035  
About • paper received ※ 03 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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THBO01 Machine Learning-Based Longitudinal Phase Space Prediction of Two-Bunch Operation at FACET-II diagnostics, simulation, experiment, linac 678
 
  • C. Emma, A.L. Edelen, M.J. Hogan, B.D. O’Shea, V. Yakimenko
    SLAC, Menlo Park, California, USA
  • A. Hanuka
    Technion, Haifa, Israel
 
  Funding: This work was supported by the U.S. Department of Energy under Contract No. DEAC02-76SF00515
We report on the application of machine learning (ML) methods for predicting the longitudinal phase space (LPS) distribution of particle accelerators. Our approach consists of training a ML-based virtual diagnostic to predict the LPS using only nondestructive linac and e-beam measurements as inputs. We validate this approach with a simulation study for the FACET-II linac and with an experimental demonstration conducted at LCLS. At LCLS, the e-beam LPS images are obtained with a transverse deflecting cavity and used as training data for our ML model. In both the FACET-II and LCLS cases we find good agreement between the predicted and simulated/measured LPS profiles, an important step towards showing the feasibility of implementing such a virtual diagnostic on particle accelerators in the future.
References:
* C. Emma, A. Edelen, M. J. Hogan, B. O’Shea, G. White, and V. Yakimenko., PRAB 21, 112802 (2018)
** A. Scheinker, A. Edelen, D. Bohler, C. Emma, A. Lutman., PRL 121, 044801 (2018)
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-THBO01  
About • paper received ※ 04 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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