Keyword: linac
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MO2C2 Beam Tuning Studies in the ESS MEBT MEBT, MMI, rfq, emittance 6
  • N. Milas, M. Akhyani, R.A. Baron, C.S. Derrez, M. Eshraqi, Y. Levinsen, R. Miyamoto, D. Noll, R. Tarkeshian, I. Vojskovic, R.H. Zeng
    ESS, Lund, Sweden
  The European Spallation Source (ESS), currently under construction and initial commissioning in Lund, Sweden, will be the brightest spallation neutron source in the world, when its driving proton linac achieves the design power of 5 MW at 2 GeV. Such a high power requires production, efficient acceleration, and almost no-loss transport of a high current beam, thus making design and beam commissioning of this machine challenging. During the the commissioning time in 2022 a campaign for a full characterisation of the ESS Medium Beta Transport session (MEBT) was carried out. Both transverse optics and longitudinal parameters were measured and compared to simulation, amongst them: buncher cavity tunning, trasnverse emittance and initial twiss parameters. In this paper we present the results and future plans.  
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DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2022-MO2C2  
About • Received ※ 07 September 2022 — Revised ※ 10 September 2022 — Accepted ※ 12 September 2022 — Issue date ※ 07 November 2022
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MOP07 Beam Instrumentation Performance During Commissioning of the ESS RFQ, MEBT and DTL DTL, MMI, MEBT, proton 32
  • T.J. Shea, R.A. Baron, C.S. Derrez, E.M. Donegani, V. Grishin, H. Hassanzadegan, I. Kittelmann, H. Kocevar, N. Milas, D. Noll, H.A. Silva, R. Tarkeshian, C.A. Thomas
    ESS, Lund, Sweden
  • I. Bustinduy
    ESS Bilbao, Zamudio, Spain
  • M. Ferianis
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • T. Papaevangelou, L. Seguí
    CEA-IRFU, Gif-sur-Yvette, France
  In late 2021 through mid 2022, the first protons were accelerated and transported through the European Spallation Source (ESS) Radio Frequency Quadrupole and Medium Energy Transport line at 3.6 MeV, and finally through the first Drift Tube Linac tank at 21 MeV. To enable these achievements, the following beam instrumentation systems were deployed: Ion Source power supply monitors, beam chopping systems, Faraday Cups, Beam Current Monitors (BCM) and Beam Position Monitors (BPM) that also measured phase. Additional systems were deployed for dedicated studies, including Wire Scanners, a slit and grid Emittance Measurement Unit, neutron Beam Loss Monitors and fast BCM and BPM systems. The instrumentation deployment is the culmination of efforts by a partnership of the ESS beam diagnostics section, multiple ESS groups and institutes across the globe. This paper summarizes the beam tests that characterized the performance of the instrumentation systems and verified the achievement of commissioning goals.  
poster icon Poster MOP07 [5.388 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2022-MOP07  
About • Received ※ 30 August 2022 — Accepted ※ 15 September 2022 — Issue date ※ 07 November 2022  
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MOP26 Bunch Length Measurement Systems at S-DALINAC* cavity, target, electron, diagnostics 96
  • A. Brauch, M. Arnold, J. Enders, L.E. Jürgensen, N. Pietralla, S. Weih
    TU Darmstadt, Darmstadt, Germany
  Funding: *Work supported by DFG (GRK 2128) and the State of Hesse within the Research Cluster ELEMENTS (Project ID 500/10.006).
A high-quality beam is necessary for electron scattering experiments at the superconducting Darmstadt electron linear accelerator S-DALINAC. An optimization of the bunch length to typical values of < 2 ps is performed to reach a high energy resolution of 1e-4. Currently, this is accomplished by inducing a linear momentum spread on the bunch in one of the accelerating cavities. The bunch length can then be measured with a target downstream. This method is time consuming and provides only an upper limit of the bunch length. Two new setups for bunch length measurements will improve the optimization process significantly. On the one hand, a new diagnostic beam line is set up in the low energy beam area. It includes a deflecting copper cavity used for measuring the bunch length by shearing the bunch and projecting its length on a target. On the other hand, a streak camera placed at different positions downstream the injector and the main linac will be used to measure the bunch length. Optical transition radiation from an aluminium coated kapton target is used to perform this measurement. The present layout of both systems and their current status will be presented in this contribution.
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2022-MOP26  
About • Received ※ 07 September 2022 — Revised ※ 09 September 2022 — Accepted ※ 11 September 2022 — Issue date ※ 12 November 2022
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MOP29 Low Gain Avalanche Detector Application for Beam Monitoring monitoring, detector, operation, electron 109
  • V. Kedych, T. Galatyuk, W. Krüger
    TU Darmstadt, Darmstadt, Germany
  • T. Galatyuk, S. Linev, J. Pietraszko, C.J. Schmidt, M. Träger, M. Traxler, F. Ulrich-Pur
    GSI, Darmstadt, Germany
  • J. Michel
    Goethe Universität Frankfurt, Frankfurt am Main, Germany
  • A. Rost
    FAIR, Darmstadt, Germany
  • V. Svintozelskyi
    Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
  Funding: This work has been supported by DFG under GRK 2128
The S-DALINAC is a superconductive linear electron accelerator operating at 3 GHz and allows operation in energy recovery mode (ERL). For the operation in the ERL mode accelerated and decelerated beams travel inside the same beamline but not necessarily share the same orbit. That leads to a bunch rate of 6 GHz. Non-destructive monitoring tools that allow optimization of acceleration and deceleration processes and achieve high recovery efficiency are important for operation in the ERL mode. The Low Gain Avalanche Detector (LGAD) is a silicon detector with internal gain layer optimized for 4-D tracking with timing resolution below 50 ps* which makes it a promising candidate for beam time structure monitoring. In this contribution we present the status of the first proof of principle beam time structure measurement with LGAD sensors at S-DALINAC in normal operation mode together with future activities overview.
* J.Pietraszko, et al., Low Gain Avalanche Detectors for the HADES reaction time (T0) detector upgrade, Eur. Phys. J. A 56, 183 (2020)
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2022-MOP29  
About • Received ※ 06 September 2022 — Revised ※ 09 September 2022 — Accepted ※ 13 September 2022 — Issue date ※ 16 October 2022
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TU2C3 Commissioning Beam-Loss Monitors for the Superconducting Upgrade to LCLS gun, cryomodule, electron, MMI 207
  • A.S. Fisher, G.W. Brown, E.P. Chin, C.I. Clarke, W.G. Cobau, T. Frosio, B.T. Jacobson, R.A. Kadyrov, J.A. Mock, J. Park, E. Rodriguez, P.K. Roy, M. Santana-Leitner, J.J. Welch
    SLAC, Menlo Park, California, USA
  Commissioning of the 4-GeV, 120-kW superconducting linac, an upgrade to the LCLS x-ray FEL at SLAC, began in summer 2022, by accelerating a beam through the first cryomodule to 100 MeV. This autumn the beam will accelerate along the full linac, pass through the bypass transport line above the copper linac, and end at a new high-power tune-up dump at the muon shield wall. The first beam through the undulators is expected by early 2023, at a rate well below the full 1 MHz. A new system of beam-loss detectors will provide radiation protection, machine protection, and diagnostics. Radiation-hard optical fibres span the full 4 km from the electron gun to the undulators and their beam dumps. Diamond detectors cover anticipated loss points. These replace ionization chambers previously used with the copper linac, due to concern about ion pile-up at high loss rates. Signals from the new detectors are integrated with a 500-ms time con-stant and compared to the allowed threshold. If this level is crossed, the beam stops within 0.2 ms. We report on the initial commissioning of this system and on the detection of losses of both photocurrent and of dark current from the gun and cryomodules.  
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DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2022-TU2C3  
About • Received ※ 08 September 2022 — Revised ※ 09 September 2022 — Accepted ※ 11 September 2022 — Issue date ※ 12 October 2022
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TUP10 Development of a New Measurement System for Beam Position Pickups in the LINAC and Beam Energy Measurement (Time of Flight) in the MEBT for Medaustron pick-up, LLRF, synchrotron, operation 238
  • M. Repovž, M. Cerv, C. Kurfürst, G. Muyan, S. Myalski, A. Pozenel, C. Schmitzer, M. Wolf
    EBG MedAustron, Wr. Neustadt, Austria
  • A. Bardorfer, B. Baričevič, P. Paglovec, M. Škabar
    I-Tech, Solkan, Slovenia
  The MedAustron Ion Therapy Centre is a synchrotron-based particle therapy facility which delivers proton and carbon beams for clinical treatment. Currently, the facility treats roughly 40 patients per day and is improving its systems and workflows to further increase this number. MedAustron was commissioned and is operational without fully integrated systems for measurements of ’time of flight’ (beam energy) in the MEBT and beam position in the LINAC. This paper presents the newly developed system for these use cases, which will improve the overall commissioning and QA accuracy. It will unify the hardware used for the cavity regulation in the injector LLRF and the synchrotron LLRF. It will also be used for SYNC pickups, Schottky monitors and RF knock-out exciter. The new system is based on the CotS MicroTCA platform, which is controlled by the MedAustron Control System based on NI-PXIe. Currently it supports fiber-optic links (SFP+), but other links (e.g. EPICS, DOOCS) can be established. The modular implementation allows for connections to other components, such as motors, amplifiers, or interlock systems and will increase the robustness and maintainability of the accelerator.  
poster icon Poster TUP10 [2.590 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2022-TUP10  
About • Received ※ 04 September 2022 — Revised ※ 09 September 2022 — Accepted ※ 11 September 2022 — Issue date ※ 28 September 2022
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TUP28 Coherent Difraction Radiation for Longitudinal Electron Beam Characteristics radiation, electron, diagnostics, FEL 291
  • R. Panaś
    NSRC SOLARIS, Kraków, Poland
  • A. Curcio
    CLPU, Villamayor, Spain
  • K. Łasocha
    Jagiellonian University, Kraków, Poland
  For the needs of diagnostics of the longitudinal electron beam characteristics at the first Polish free electron laser (PolFEL) project, a Coherent Diffraction Radiation (CDR) system is being developed and tested. It will allow for nondestructive bunch length measurement based on the power balance of CDR radiation collected by Schottky diodes in different ranges of sub-THz radiation. The first tests and measurements will be performed at the end of the Solaris synchrotron injector linac, where the beam profile is already known from previous studies. In addition the camera system with automatic focus was developed and tested. In this contribution the theoretical background of the measurement, calculations and first experimental steps will be presented.  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2022-TUP28  
About • Received ※ 07 September 2022 — Revised ※ 10 September 2022 — Accepted ※ 11 September 2022 — Issue date ※ 13 September 2022
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TUP32 Differential Current Transformer for Beam Charge Monitoring in Noisy Environments electron, pick-up, monitoring, laser 304
  • H. Maesaka, T. Inagaki
    RIKEN SPring-8 Center, Hyogo, Japan
  • H. Dewa, T. Inagaki, H. Maesaka, K. Yanagida
    JASRI, Hyogo, Japan
  • K. Ueshima
    QST, Sendai, Miyagi, Japan
  We developed a differential current transformer (CT) for electron beam charge measurement in noisy environments, such as near high-power pulse sources. This CT has four pickup wires coiled at equal intervals (90 deg.) on a toroidal core and each coil is wound for two turns. The midpoint of the coil is connected to the body ground so that a balanced differential signal is generated at both ends. A beam pipe with a ceramics insulation gap is inserted into the toroidal core to obtain a signal from a charged-particle beam. The four pairs of signals are transmitted through a CAT6 differential cable and fed into differential amplifiers. The common-mode noise from the noisy ground at the CT is canceled out by the amplifier. The four signals are then summed and digitized by an AD converter. We produced differential CTs and installed them into the new injector linac of NewSUBARU (*). Before the installation, the frequency response was measured in a laboratory and a flat response of up to 100 MHz was obtained as expected. Common-mode noise cancellation was also confirmed at NewSUBARU and the CTs have been utilized for beam charge monitoring stably.
*: T. Inagaki et al., ’Construction of a Compact Electron Injector Using a Gridded RF Thermionic Gun and a C-Band Accelerator’, in Proc. IPAC’21, pp. 2687-2689. doi:10.18429/JACoW-IPAC2021-WEPAB039
poster icon Poster TUP32 [1.393 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2022-TUP32  
About • Received ※ 07 September 2022 — Revised ※ 10 September 2022 — Accepted ※ 11 September 2022 — Issue date ※ 26 October 2022
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TUP35 First RF Phase Scans at the European Spallation Source DTL, cavity, MMI, simulation 313
  • Y. Levinsen, R.A. Baron, E.M. Donegani, M. Eshraqi, A. Garcia Sosa, H. Hassanzadegan, B. Jones, N. Milas, R. Miyamoto, D. Noll, I. Vojskovic, R.H. Zeng
    ESS, Lund, Sweden
  • M. Akhyani
    EPFL, Lausanne, Switzerland
  • I. Bustinduy
    ESS Bilbao, Zamudio, Spain
  • F. Grespan
    INFN/LNL, Legnaro (PD), Italy
  The installation and commissioning of the European Spallation Source is currently underway at full speed, with the goal to be ready for first neutron production by end of 2024. This year we accelerated protons through the first DTL tank. This included the RFQ, 3 buncher cavities in the medium energy beam transport as well as the DTL tank itself as RF elements. At the end of the DTL tank we had a Faraday cup acting as the effective beam stop. This marks the first commissioning when RF matching is required for beam transport. In this paper we discuss the phase scan measurements and analysis of the buncher cavities and the first DTL tank.  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2022-TUP35  
About • Received ※ 08 September 2022 — Revised ※ 10 September 2022 — Accepted ※ 12 September 2022 — Issue date ※ 03 October 2022
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TU3C3 LINAC4 Laser Profile and Emittance Meter Commissioning laser, emittance, detector, electron 357
  • A. Goldblatt, O.O. Andreassen, T. Hofmann, F. Roncarolo, J. Tagg
    CERN, Meyrin, Switzerland
  • G.E. Boorman, A. Bosco, S.M. Gibson
    Royal Holloway, University of London, Surrey, United Kingdom
  The LINAC4 is now equipped with two laser profile and emittance meters, basically non destructive and not limited by beam power density. A pulsed laser is transported through fibres and focused into the 160 MeV H beam. Its interaction with the H ions detaches electrons that are collected by an electron-multiplier, while the resultingH0 particles, after being separated from the main H beam by a dipole magnet, are recorded by a diamond strip detector, few meters away from the interaction point. The emittance and profile are reconstructed from the laser step by step scan of the beam. After several years of feasibility tests and prototyping, this paper will present all details about the final HW and SW implementation and the 2022 experimental results.  
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DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2022-TU3C3  
About • Received ※ 09 September 2022 — Revised ※ 10 September 2022 — Accepted ※ 11 September 2022 — Issue date ※ 23 September 2022
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WEP17 Electron Emission (SEM) Grids for the FAIR Proton Linac proton, electron, diagnostics, experiment 426
  • J. Herranz
    Proactive Research and Development, Sabadell, Spain
  • I. Bustinduy, .A. Rodríguez Páramo
    ESS Bilbao, Zamudio, Spain
  • P. Forck, T. Sieber
    GSI, Darmstadt, Germany
  • A. Navarro Fernandez
    CERN, Meyrin, Switzerland
  New SEM-Grid has been developed for FAIR Proton Linac, the instrument consists of 2 harps fixed together in an orthogonal way. This SEM-Grid will provide higher resolution and accuracy measurements as each harp consists of 64 tungsten wires 100 micro-meter in diameter and 0.5 mm pitch. Each wire is fixed to a ceramic PCB with an innovative dynamic stretching system, this system assures wire straightness under typical thermal expansion due to beam heat deposition. Electric field distribution has been performed, 3 main parameters have been optimized, wires distribution, quantity of polarization electrodes and distance between electrodes and wires. The design and production of the SEM-Grids have been performed by the company Proactive R&D that has count on the expertise of ESS-Bilbao to define safe operation limits and signal estimation by means of a code developed specifically for this type of calculations. Preliminary validations of the first prototypes shown good values of electric field behaviour signal. After additional beam test validations to be performed on June 2022, final series of the SEM-Grid will be produced and installed on FAIR proton LINAC.  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2022-WEP17  
About • Received ※ 07 September 2022 — Revised ※ 15 September 2022 — Accepted ※ 18 September 2022 — Issue date ※ 22 September 2022
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TH1I1 First Measurement of Longitudinal Profile of High-Power and Low-Energy H Beam by Using Bunch Shape Monitor with Graphite Target target, MEBT, electron, simulation 532
  • R. Kitamura
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  At J-PARC Linac, bunch shape monitors (BSMs) have been used to measure a longitudinal profile of high power H beam. Operational principle of the monitor is similar to that of the streak-camera. The BSM inserts a biased-solid target into H beam to extract and accelerate secondary electrons. These electrons are then modulated with synchronized RF. After passing through dipole B field, a longitudinal profile is converted to a transverse one. For the BSM, a choice of target material is essential to reduce beam loss and to have sufficient tolerance for breakage by the interaction with high power beams. The BSM with graphite target realized the measurement of high-power 3 MeV beam for the first time.  
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DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2022-TH1I1  
About • Received ※ 06 September 2022 — Revised ※ 11 September 2022 — Accepted ※ 13 September 2022 — Issue date ※ 06 December 2022
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