Keyword: HOM
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MOPOST030 Proton Irradiation Site for Si-Detectors at the Bonn Isochronous Cyclotron radiation, cyclotron, proton, site 130
 
  • D. Sauerland, R. Beck, P.D. Eversheim
    HISKP, Bonn, Germany
  • J. Dingfelder, P. Wolf
    SiLab, Bonn, Germany
 
  The Bonn Isochronous Cyclotron provides proton, deuteron, alpha particle and other light ion beams with a charge-to-mass ratio Q/A of ’ 1/2 and kinetic energies ranging from 7 to 14 MeV per nucleon. At a novel irradiation site, a 14 MeV proton beam with a diameter of a few mm is utilized to homogeneously irradiate silicon detectors, so-called devices under test (DUTs), to perform radiation hardness studies. Homogeneous irradiation is achieved by moving the DUT through the beam in a row-wise scan pattern with constant velocity and a row separation smaller than the beam diameter. During the irradiation procedure, the beam parameters are continuously measured non-destructively using a calibrated, secondary electron emission-based beam monitor, installed at the exit window of the beamline. The diagnostics and the irradiation procedure ensure a homogeneous irradiation with a proton fluence error of smaller than 2 %. In this work, an overview of the accelerator facility is given and the irradiation site with its beam diagnostics is presented in detail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST030  
About • Received ※ 08 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 07 July 2022  
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MOPOST033 Betatron Tune Characterization of the Rutgers 12-Inch Cyclotron for Different Magnetic Poles Configurations focusing, cyclotron, betatron, experiment 136
 
  • C. Hernalsteens
    CERN, Meyrin, Switzerland
  • B.L. Beaudoin, T.W. Koeth
    UMD, College Park, Maryland, USA
  • M. Miller
    Brown University, Providence, USA
  • T.S. Ponter
    IBA, Louvain-la-Neuve, Belgium
  • K.J. Ruisard
    ORNL, Oak Ridge, Tennessee, USA
  • R. Tesse
    ULB, Bruxelles, Belgium
 
  The Rutgers cyclotron is a small 12-Inch, 1.2MeV proton cyclotron. Sets of magnet pole-tips were designed to demonstrate different cyclotron focusing options: weak focusing, radial sector focusing and spiral sector focusing. The purpose of this paper is to experimentally characterize the transverse dynamics provided by different types of focusing. Magnetic field measurements provide insight into the as-built properties of these magnetic poles configurations. First we discuss the axial betatron tune measurements as a function of the beam energy towards outer radii, which agree well with the values expected from measured magnetic data. Turn-by-turn betatron envelope oscillation measurements are also reported and compared with the tune measurements. Excellent agreement is once again found.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST033  
About • Received ※ 09 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 08 July 2022
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MOPOPT006 Characterization of the Electron Beam Visualization Stations of the ThomX Accelerator target, diagnostics, MMI, controls 240
 
  • A. Moutardier, C. Bruni, J-N. Cayla, I. Chaikovska, S. Chancé, N. Delerue, H. Guler, H. Monard, M. Omeich, S.D. Williams
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • S.D. Williams
    The University of Melbourne, Melbourne, Victoria, Australia
 
  Funding: Research Agency under the Equipex convention ANR-10-EQPX-0051.
We present an overview of the diagnostics screens stations - named SSTs - of the ThomX compact Compton source. ThomX is a compact light source based on Compton backscattering. It features a linac and a storage ring in which the electrons have an energy of 50 MeV. Each SST is composed of three screens, a YAG:Ce screen and an Optical Transition Radiation (OTR) screen for transverse measurements and a calibration target for magnification and resolution characterisation. The optical system is based on commercial lenses that have been reverse-engineered. An Arduino is used to control both the aperture and the focus remotely, while the magnification must be modified using an external motor. We report on the overall performance of the station as measured during the first steps of beam commissioning and on the optical system remote operations.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT006  
About • Received ※ 20 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 17 June 2022
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MOPOPT058 Machine Learning Training for HOM Reduction in a TESLA-Type Cryomodule at FAST cavity, electron, emittance, experiment 400
 
  • J.A. Diaz Cruz
    UNM-ECE, Albuquerque, USA
  • J.A. Diaz Cruz, A.L. Edelen, B.T. Jacobson, J.P. Sikora
    SLAC, Menlo Park, California, USA
  • D.R. Edstrom, A.H. Lumpkin, R.M. Thurman-Keup
    Fermilab, Batavia, Illinois, USA
 
  Low emittance electron beams are of high importance at facilities like the Linac Coherent Light Source II (LCLS-II) at SLAC. Emittance dilution effects due to off-axis beam transport for a TESLA-type cryomodule (CM) have been shown at the Fermilab Accelerator Science and Technology (FAST) facility. The results showed the correlation between the electron beam-induced cavity high-order modes (HOMs) and the Beam Position Monitor (BPM) measurements downstream the CM. Mitigation of emittance dilution can be achieved by reducing the HOM signals. Here, we present a couple of Neural Networks (NN) for bunch-by-bunch mean prediction and standard deviation prediction for BPMs located downstream the CM.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT058  
About • Received ※ 15 June 2022 — Revised ※ 18 June 2022 — Accepted ※ 24 June 2022 — Issue date ※ 26 June 2022
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TUPOPT050 Investigation of Polarization Dependent Thomson Scattering in an Energy-Recovering Linear Accelerator on the Example of Mesa electron, scattering, photon, polarization 1114
 
  • C.L. Lorey, A. Meseck
    KPH, Mainz, Germany
 
  Funding: GRK 2128 AccelencE funded by the DFG
At the Johannes Gutenberg University (JGU) in Mainz, a new accelerator is currently under construction in order to deliver electron beams of up to 155 MeV to two experiments. The Mainz Energy-recovering Superconducting Accelerator (MESA) will offer two modes of operation, one of which is an energy-recovering (ER) mode. As an ERL, MESA, with it’s high brightness electron beam, is a promising accelerator for supplying a Thomson back scattering based Gamma source. Furthermore, at MESA, the polarization of the electron beam can be set by the injector. The aim of this work is to provide a concept and comprehensive analysis of the merit and practical feasibility of a Thomson backscattering source at MESA under consideration of beam polarization and transversal effects. In this paper, an overview and results of our semi analytical approach to calculate various Thomson back scattering light source scenarios at MESA will be given. Furthermore we will discuss the benefits of using polarized electrons in combination with a polarized laser beam.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT050  
About • Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 26 June 2022
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TUPOTK014 Refurbishment of SRF Cavities and HOM Antenna Coating Studies for the Mainz Energy-Recovering Superconducting Accelerator (MESA) cavity, cryomodule, SRF, linac 1226
 
  • P.S. Plattner, F. Hug, T. Stengler
    KPH, Mainz, Germany
 
  Funding: The work received funding by BMBF through 05H21UMRB1.
The Mainz Energy-Recovering Superconducting Accelerator (MESA) will be a new recirculating accelerator, which can operate in an external beam mode and an energy recovering mode. In the ERL-mode the electrons cross an internal gas-target at MAGIX and give their kinetic energy into the Superconducting Radio Frequency (SRF) system back after experimental use. The MESA cryomodules are based on ELBE-type cryomodules, which contain two 9-cell TESLA/XFEL-type cavities. For any maintenance the clean room infrastructure at the Helmholtz Institute Mainz (HIM) can be used. Currently, a cryomodule from the decommissioned ALICE ERL at Daresbury, UK is in the process of refurbishment. The refurbishment includes an HPR rinse of the cavities suffering from field emission at present and various adjustments of the module for a future use in MESA, which includes adding piezo tuners and new HOM antennas. For the new antennas, different superconducting coatings (Nb3Sn and NbTiN) will be tested to reach higher critical temperatures in the future for giving the possibility to couple out more HOM power without quenching as the prospected cw beamload lays above 4 mA in MESA ERL operation. Using a superconducting 3 GHz six-cell injector cavity for the S-DALINAC the successful refurbishment of a SRF cavity by applying a high pressure rinse in the clean room infrastructure at HIM was demonstrated the first time.
* The authors acknowledge the transfer of one cryomodule to Mainz by STFC Daresbury.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK014  
About • Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 23 June 2022
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TUPOTK015 HOM Coupler Design and Optimization for the FCC-ee W Working Point cavity, impedance, multipactoring, damping 1230
 
  • S. Udongwo, S.G. Zadeh, U. van Rienen
    Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
  • R. Calaga
    CERN, Meyrin, Switzerland
 
  Funding: Funded by CERN under ADDENDUM FCC-GOV-CC-00213 (KE4978/ ATS) to FCC-GOV-CC- 0213/2431149/KE4978 VERSION 1.0.
The Future Circular electron-positron Collider (FCC-ee) is planned to operate with beam energies from 45.6 to 182.5 GeV and beam currents from 5.4 to 1390 mA. The purpose is to study the properties of the Z-, W- and Higgs boson and the top and anti-top quarks in four operation points. The beam current of 147 mA of the W working point requires particular care to string damp HOMs. This paper proposes 2-cell 400 MHz SRF cavities with improved damping as an alternative to the baseline 4-cell cavities for this working point. The resulting impedance of the HOM-damped cavity is then calculated and compared with the impedance budget.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK015  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022
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TUPOTK025 Design Study of the Third Harmonic Superconducting Cavity for a Bunch Lengthening cavity, superconducting-cavity, status, vacuum 1258
 
  • J.Y. Yoon, E.-S. Kim
    KUS, Sejong, Republic of Korea
  • J.H. Han, H.S. Park
    Kiswire Advanced Technology Ltd., Daejeon, Republic of Korea
  • E. Kako
    KEK, Ibaraki, Japan
 
  The bunch lengthening by the 3rd harmonic cavity reduces the electron collisions in a bunch and increases the Touschek lifetime of a storage ring. We performed the multi-physics simulations including the electromagnetic, thermal, and mechanical analysis of the cavity. In the electromagnetic simulation, the geometry is optimized for the required performance of the cavity. The elliptical double-cell geometry is selected to increase the accelerating voltage and reduce the power losses of the cavity. Thermal/mechanical analyses were performed to check the deformation of the thermal and pressure contraction. The prototype cavity does not require the power coupler as it is a passive type. The conceptual design and copper prototype of the 3rd harmonic cavity will be described in this paper. Based on this design, the fabrication of Niobium cavity is in progress.
Superconducting RF, Cavity
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK025  
About • Received ※ 02 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 09 July 2022
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TUPOTK040 Design of the Electron Ion Collider Electron Storage Ring SRF Cavity cavity, impedance, simulation, operation 1307
 
  • J. Guo, E. Daly, J. Henry, J. Matalevich, G.-T. Park, R.A. Rimmer, H. Wang, S. Wang
    JLab, Newport News, Virginia, USA
  • D. Holmes, K.S. Smith, W. Xu, A. Zaltsman
    BNL, Upton, New York, USA
 
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
The Electron Ion Collider (EIC) under construction at Brookhaven National Laboratory is a high luminosity collider as the next major research facility for the nuclear physics community. Among the numerous RF subsystems in the EIC, the electron storage ring (ESR) fundamental RF cavities system is one of the most challenging. This system will handle a high beam current of up to 2.5 A and replenish up to 10 MW of beam power losses from synchrotron radiation and HOM. Variable coupling is required in the cavities due to the wide range of required total RF voltage and beam current combinations. In this paper, we will present the status of the design and future plans.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK040  
About • Received ※ 16 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 28 June 2022
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TUPOTK048 Optimization of a 600 MHz Two-Cell Slotted Waveguide Elliptical Cavity for FCC-ee cavity, impedance, collider, GUI 1323
 
  • S. Gorgi Zadeh, O. Brunner, F. Peauger, I. Syratchev
    CERN, Meyrin, Switzerland
 
  The radio-frequency (RF) system of the future circular lepton collider (FCC-ee) must cope with different machine parameters ranging from Ampere-class operation required for the Z-peak working point to the high-gradient operation for the ttbar threshold. The Superconducting Slotted Waveguide Elliptical cavity (SWELL) concept was recently proposed as an alternative to the challenging RF baseline design of the FCC-ee. In this paper, random optimization methods are used to minimize the peak surface magnetic field and the maximum longitudinal impedance of the higher order modes (HOM) of a two-cell \unit[600]{MHz} SWELL cavity. In the next step, the waveguide slots are optimized to first have a smooth transition from the cavity to the slots to avoid large peak surface fields and second to achieve high transmission at dipole mode frequencies and low transmission at fundamental mode frequency while keeping the design compact.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK048  
About • Received ※ 23 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 15 June 2022
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TUPOTK064 HL-LHC Crab Cavity HOM Couplers: Challenges and Results cavity, impedance, simulation, cryomodule 1374
 
  • J.A. Mitchell, R. Calaga, E. Montesinos
    CERN, Meyrin, Switzerland
 
  To compensate for the detrimental effect of the crossing angle on luminosity production in the High Luminosity Large Hadron Collider’s (HL-LHC) interaction regions, superconducting crab cavities (vertical and horizontal) will be installed at the two interaction regions of the ATLAS and CMS experiments. Both cavity designs use multiple Higher Order Mode (HOM) couplers to reduce beam instabilities and heat loads caused by the very high proton current in the HL-LHC. The conceptual RF designs of the HOM couplers are firstly presented, evaluating HOM damping requirements, fundamental mode rejection and dynamic heat load constraints. A special focus is given to the coupler’s characteristic impedance (Z0), to improve the robustness during transport and operation. Following this, RF measurements of the HOM couplers before installation, installed on the superconducting cavities and with a circulating proton beam are detailed, analysing deviations from the simulated cases.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK064  
About • Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 10 July 2022
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TUPOTK065 Design of a Passive Superconducting Harmonic Cavity for HALF Storage Ring cavity, storage-ring, cryomodule, impedance 1378
 
  • Y. Wei, B. Du, G. Feng, D. Jia, J. Pang, S.C. Zhang
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  • C.P. Welsch, H.D. Zhang
    The University of Liverpool, Liverpool, United Kingdom
  • C.P. Welsch, H.D. Zhang
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  Higher harmonic cavities, also known as Landau cavities, have been proposed to improve beam lifetime and provide Landau damping by lengthening the bunch without energy spread for stable operations of present and future low-emittance storage rings. This contribution presents design of a passive superconducting 3rd-harmonic cavity (super-3HC) for the planned Hefei Advanced Light Facility (HALF) at University of Science and Technology of China. It is designed to provide 0.43 MV at 1499.4 MHz for the nominal 2.2 GeV, 350 mA electron beam, and 1.44 MV main RF voltage in storage ring. Through optimizations it has a low R/Q < 45 Ohm, which has potential to achieve a good bunch lengthening. Higher-order-modes are strongly damped using a pair of room-temperature silicon carbide (SiC) rings to meet the requirement of beam instabilities. In addition, preliminary engineering design for the super-3HC cryomodule is also described in this contribution.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK065  
About • Received ※ 03 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
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TUPOMS010 BESSY III Status Report and Lattice Design Process lattice, sextupole, emittance, radiation 1417
 
  • P. Goslawski, M. Abo-Bakr, M. Arlandoo, J. Bengtsson, K. Holldack, A. Jankowiak, B.C. Kuske, A. Meseck, M.K. Sauerborn, M. Titze, J. Viefhaus, J. Völker
    HZB, Berlin, Germany
 
  Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association.
Since 2020 a detailed discussion about a BESSY~II successor is ongoing at HZB and its user community in order to define the science and layout of the new facility. Still free locations close to BESSY~II have triggered a discussion about a greenfield project, but in-house upgrade solutions have also been investigated. As an additional boundary condition, BESSY~III has to meet the requirement of the Physikalische Technische Bundesanstalt (PTB) for radiation sources for metrology applications and bending magnet sources for tender X-rays. A Conceptional Design Report is in preparation. Here, we give a status report including a first parameter space, technical specifications and a first candidate for the linear lattice.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS010  
About • Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 25 June 2022
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TUPOMS028 3HC - Third Harmonic Normal Conducting Active Cavity Collaboration Between HZB, DESY and ALBA cavity, impedance, simulation, storage-ring 1471
 
  • F. Pérez, J.R. Ocampo, A. Salom, P. Solans
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  • W. Anders, V. Dürr, T. Loewner, A.N. Matveenko, M. Ries, L. Shi, Y. Tamashevich, A.V. Tsakanian
    HZB, Berlin, Germany
  • M. Ebert, R. Onken
    DESY, Hamburg, Germany
  • P. Hülsmann
    GSI, Darmstadt, Germany
  • W.F.O. Müller
    TEMF, TU Darmstadt, Darmstadt, Germany
 
  Funding: Co-funded by the European Regional Development Fund (ERDF)
A collaboration agreement between the HZB, DESY and ALBA institutions was signed on 2021 in order to test the 3rd harmonic normal conducting, HOM damped, active cavity designed and prototyped by ALBA*. The test will involve low power characterization of the fundamental mode, bead pull measurements to fully determine the HOM characteristics, a full high power conditioning to validate the power capability of the cavity, and finally, the installation of the cavity in the BESSY II storage ring in order to test the cavity in real conditions with beam. In this paper the low power, bead pull and conditioning results will be presented. The cavity has been installed at BESSY II on May 2022 to be tested after the summer shutdown.
* Prototype fabrication of an active normal conducting third harmonic cavity for the ALBA Storage Ring. J.Ocampo et al. , IPAC 2022 proceedings.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS028  
About • Received ※ 06 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 02 July 2022
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TUPOMS040 Characterization of Higher-Order-Modes (HOM) in THOMX Storage Ring RF Cavity cavity, controls, storage-ring, impedance 1513
 
  • M. El Khaldi, J-N. Cayla, H. Monard
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • M. Diop, F. Ribeiro
    SOLEIL, Gif-sur-Yvette, France
 
  The RF system of the ThomX storage ring consists in a 500 MHz single cell copper cavity of the ELETTRA type, powered with a 50 kW CW solid state amplifier, and the associated Low-Level RF feedback and control loops. The low operating energy of 50-100 MeV makes the impedances of the cavity higher order modes (HOMs) particularly critical for the beam stability. Their parasitic effects on the beam can be cured by HOM frequency shifting techniques, based on a fine temperature tuning and a dedicated adjustable plunger. A cavity temperature stability of ± 0.1 °C within a range from 30 up to 70 °C is achieved by a precise control of its water-cooling temperature. On the other hand, the tuning of the cavity fundamental mode is achieved by changing its axial length by means of a mechanical tuner. In order to insure a fine control of the HOM frequencies, a good knowledge of their characteristics is mandatory. The main parameters of the fundamental and of the HOMs up to 2.2 GHz versus temperature have been measured at low power using a vector network analyzer (VNA).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS040  
About • Received ※ 03 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 21 June 2022
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TUPOMS051 Prototype Fabrication of an Active Normal Conducting Third Harmonic Cavity for the ALBA Storage Ring cavity, GUI, simulation, storage-ring 1542
 
  • J.R. Ocampo, J.M. Álvarez, B. Bravo, F. Pérez, A. Salom, P. Solans
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
 
  Funding: Co-funded by the European Regional Development Fund (ERDF)
ALBA has designed a normal conducting active 1.5 GHz HOM damped cavity for the active third harmonic RF system for the ALBA Storage Ring (SR), which also will serve for the upgraded ALBA II. The third harmonic cavity at ALBA will be used to increase the bunch length in order to improve the beam lifetime and increase the beam stability thresholds. A prototype has been constructed by the company AVS in collaboration with VITZRO. This paper presents the design of the cavity, the constructed prototype, the Acceptance Tests measurements, and the future plans.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS051  
About • Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 30 June 2022 — Issue date ※ 01 July 2022
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TUPOMS061 RF System Design for Elettra 2.0 cavity, storage-ring, operation, booster 1570
 
  • C. Pasotti, M. Bocciai, L. Bortolossi, M. Rinaldi
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
 
  The Elettra 2.0 low emittance light source project aims to a substantial increase of the brilliance and coherence fraction of the source improving, at the same time, the storage ring stability and reliability. The Radio Frequency (RF) system plays a pivotal role in the beam quality, stability and reliability for the user operation. This paper will cover the design and the implemented strategy to meet these features for the Elettra 2.0 RF system. Starting point of the new RF design is the final choice of the RF frequency, 500 MHz, and the available room, 1260 mm, to install the accelerating cavities. Thanks to the 500 MHz frequency choice, some components of the new RF system for Elettra 2.0 are already installed and set into operation in the current Elettra storage ring. Their features and performance’s optimization can therefore start well in advance with respect to the foreseen operation the new Elettra 2.0 storage ring.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS061  
About • Received ※ 06 June 2022 — Accepted ※ 21 June 2022 — Issue date ※ 04 July 2022  
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WEOYSP2 First Electron Beam of the ThomX Project linac, gun, electron, emittance 1632
 
  • C. Bruni, M. Alkadi, J-N. Cayla, I. Chaikovska, S. Chancé, V. Chaumat, O. Dalifard, N. Delerue, K. Dupraz, M. El Khaldi, N. ElKamchi, E.E. Ergenlik, P. Gauron, A. Gonnin, E. Goutierre, H. Guler, M. Jacquet, V. Kubytskyi, P. Lepercq, F. Letellier-Cohen, J.C. Marrucho, B. Mercier, E. Mistretta, H. Monard, A. Moutardier, M. Omeich, V. Soskov, F. Wicek
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
 
  Funding: The present work is financed by the French National Research Agency (ANR) under the Equipex program ANR-10-EQPX-0051.
The ThomX accelerator beam commissioning phase is now ongoing. The 50 MeV electron accelerator complex consists of a 50 MeV linear accelerator and a pulsed mode ring. It is dedicated to the production of X-rays by Compton backscattering. The performance of the beam at the interaction point is demanding in terms of emittance, charge, energy spread and transverse size. The choice of an undamped ring in pulsed mode also stresses the performance of the beam from the linear accelerator. Thus, commissioning includes a beam based alignment and a simulation/experimental matching procedure to reach the X-ray beam requirements. We will present the first 50 MeV electron beam obtained with ThomX and its characteristics.
on behalf of the ThomX collaboration : ThomX collaboration, https://thomx.ijclab.in2p3. fr/collaboration-thomx/, [Online; accessed 19-May- 2022].
 
slides icon Slides WEOYSP2 [80.558 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOYSP2  
About • Received ※ 08 June 2022 — Revised ※ 21 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 06 July 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOPT020 Modeling RHIC Spin Tilt as Lattice Imperfections resonance, proton, injection, lattice 1884
 
  • V.H. Ranjbar, E.C. Aschenauer, H. Huang, A. Marusic, F. Méot, V. Schoefer
    BNL, Upton, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
A tilt in the spin direction from the vertical has been observed for a number of years in the RHIC collider during store. This tilt has been extensively studied by scanning snake strengths, energies and orbital angles during the 2017 polarized proton run. Using a spin transport model, we attempt to model this spin tilt by fitting all the relevant data.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT020  
About • Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 18 June 2022
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WEPOTK039 Radiation of a Particle Moving Along a Helical Trajectory in a Semi-Infinite Cylindrical Waveguide GUI, radiation, undulator, injection 2154
 
  • M. Ivanyan, A. Grigoryan, B. Grigoryan, V.G. Khachatryan, B.K. Sargsyan
    CANDLE SRI, Yerevan, Armenia
  • K. Flöttmann, F. Lemery
    DESY, Hamburg, Germany
  • A. Grigoryan
    YSU, Yerevan, Armenia
 
  Funding: The work was supported by the Science Committee of RA, in the frames of the research project 21T-1C239
The radiation field of a particle which suddenly appears in an ideal waveguide and moves on a helical trajectory under the influence ofexternal magnetic fields is calculated. The shape and character of the front of the propagating wave is determined. The time dependence of radiation energy accumulated in the waveguide is investigated.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK039  
About • Received ※ 31 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 05 July 2022 — Issue date ※ 06 July 2022
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WEPOMS008 Impact of Broadband Impedance on Longitudinal Coupled-Bunch Instability Threshold impedance, synchrotron, cavity, damping 2245
 
  • I. Karpov, E.N. Shaposhnikova
    CERN, Meyrin, Switzerland
 
  Coupled-bunch instabilities (CBI) and the loss of Landau damping (LLD) in the longitudinal plane can affect the performance of high-current synchrotrons. The former is driven by the narrowband impedance of resonant structures, while the latter is mainly determined by the broadband impedance of the entire accelerator and is a single-bunch effect. Therefore, the CBI and LLD thresholds are usually evaluated separately in order to define the corresponding critical impedance budget for given beam parameters. In this paper, we show that the CBI threshold in the presence of broadband impedance can be significantly lower than the one defined by only the narrowband impedance, especially if the LLD threshold is below the CBI threshold. In some cases, the beam becomes unstable even below the LLD threshold. This explains the low CBI threshold observed for the LHC-type beams in the CERN SPS. For HL-LHC, the broadband impedance may also significantly reduce the CBI threshold driven by higher-order modes of the crab cavities.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS008  
About • Received ※ 08 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 06 July 2022  
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOMS010 Studies of Transverse Coupled-Bunch Instabilities from Resistive-Wall and Cavity Higher Order Modes for Diamond-II impedance, cavity, simulation, storage-ring 2253
 
  • S.W. Wang, H.C. Chao, R.T. Fielder, I.P.S. Martin, T. Olsson
    DLS, Oxfordshire, United Kingdom
 
  The transverse coupled-bunch instabilities from resistive-wall impedance and main cavity higher order modes (HOMs) are studied for the Diamond-II storage ring. The growth rates of all the coupled-bunch modes are calculated using both the results from tracking simulations and analytic formula, which show a good consistency. The instability threshold from the resistive-wall impedance is estimated and verified by simulation. The impact of the main cavity HOMs is studied in a similar way, and the results show instabilities from HOMs are much smaller than that from resistive-wall impedance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS010  
About • Received ※ 06 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 05 July 2022  
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WEPOMS042 The HOMEN Model: An Estimator of High Order Modes Evolution in an Energy Recovery Linac cavity, electron, acceleration, linac 2342
 
  • S. Samsam, A. Bacci, V. Petrillo, M. Rossetti Conti, A.R. Rossi, M. Ruijter, L. Serafini
    INFN-Milano, Milano, Italy
  • A. Bosotti, R. Paparella, D. Sertore
    INFN/LASA, Segrate (MI), Italy
  • M.R. Masullo, A. Passarelli
    INFN-Napoli, Napoli, Italy
  • M. Opromolla
    Università degli Studi di Milano, Milano, Italy
 
  Energy recovery linacs represent the new frontier of energy sustainability in the field of particle accelerators while providing remarkable performance in terms of high average current and average brightness. Operating superconducting radio-frequency cavities in continuous wave makes high repetition rates (GHz-class) affordable and allows the construction of light sources such as FEL or Compton based characterized by high flux. \ This study originates in the context of the design study of BriXSinO, an ERL based on the two-pass two-way scheme à la Maury Tigner in which the cavities are traveled by the beam in both directions, the first time in the accelerating phase and the second time in the decelerating phase. HOMEN was conceived as a model to simulate the evolution of high order modes on long time scales in high Q cavities of machines of this kind and monitor their effects on the beam.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS042  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 21 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOMS045 Modeling and Mitigation of Long-Range Wakefields for Advanced Linear Colliders linac, wakefield, collider, dipole 2350
 
  • F. Bosco, M. Carillo, L. Giuliano, M. Migliorati, A. Mostacci, L. Palumbo
    Sapienza University of Rome, Rome, Italy
  • O. Camacho, A. Fukasawa, N. Majernik, J.B. Rosenzweig
    UCLA, Los Angeles, USA
  • E. Chiadroni, B. Spataro, C. Vaccarezza
    LNF-INFN, Frascati, Italy
  • L. Faillace, A. Giribono
    INFN/LNF, Frascati, Italy
 
  Funding: This work is supported by DARPA under Contract N.HR001120C0072, by DOE Contract DE-SC0009914 and DE-SC0020409, by the National Science Foundation Grant N.PHY-1549132 and by INFN.
The luminosity requirements of TeV-class linear colliders demand use of intense charged beams at high repetition rates. Such features imply multi-bunch operation with long current trains accelerated over the km length scale. Consequently, particle beams are exposed to the mutual parasitic interaction due to the long-range wakefields excited by the leading bunches in the accelerating structures. Such perturbations to the motion induce transverse oscillations of the bunches, potentially leading to instabilities such as transverse beam break-up. Here we present a dedicated tracking code that studies the effects of long-range transverse wakefield interaction among different bunches in linear accelerators. Being described by means of an efficient matrix formalism, such effects can be included while preserving short computational times. As a reference case, we use our code to investigate the performance of a state-of-the-art linear collider currently under design and, in addition, we discuss possible mitigation techniques based on frequency detuning and damping.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS045  
About • Received ※ 20 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 10 July 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THOYSP1 Construction and Measurement of a Tuneable Permanent Magnet Quadrupole for Diamond Light Source permanent-magnet, quadrupole, simulation, radiation 2424
 
  • A.R. Bainbridge, B.J.A. Shepherd
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • A.G. Hinton, N. Krumpa
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • I.P.S. Martin, W. Tizzano
    DLS, Oxfordshire, United Kingdom
 
  Permanent magnets (PMs) are becoming an attractive proposition as a green and efficient replacement for electromagnets in particle accelerators. The Zero-Power Tuneable Optics (ZEPTO) collaboration between STFC and CERN has demonstrated that traditional limitations of PM technology, such as the ability to change the flux density in the magnet aperture, can be overcome. Moving PM blocks relative to fixed steel structures that define the field, the strength may be changed while suitable field homogeneity is maintained. A new ZEPTO variant has been developed in conjunction with Diamond Light Source (DLS) to demonstrate the technology on a real accelerator. This magnet features a number of crucial design innovations over previous generations of ZEPTO magnets that improve the convenience and versatility of PM systems and demonstrate that they can be deployed in many situations. We present the construction and measurement results of this new magnet and outline the planned data collection whilst installed on DLS. We analyse its performance relative to design and discuss the new features with focus on the real-world implications of PM technology for current and future accelerators.  
slides icon Slides THOYSP1 [3.675 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THOYSP1  
About • Received ※ 30 May 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 27 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOTK001 Variable Permanent Hybrid Magnets for the Bessy III Storage Ring dipole, lattice, quadrupole, storage-ring 2763
 
  • J. Völker, V. Dürr, P. Goslawski, A. Jankowiak, M. Titze
    HZB, Berlin, Germany
 
  The Helmholtz Zentrum Berlin (HZB) is working on the conceptual design of a successor source to BESSY II, an new BESSY III facility, designed for a beam energy of 2.5GeV and based on a multi-bend achromat (MBA) lattice for a low emittances of 100pm-rad. Bending and focusing magnets in the MBA cells should consist of permanent magnets (PM), to allow for a competitive and compact lattice, to increase the magnetic stability and to decrease the electric power consumption of the machine. However, using pure permanent magnet systems would result in a completely fixed lattice. Therefore, we are developing Variable Permanent Hybrid Magnets (VPHM), combining PM materials like NdFeB with a surrounding soft iron yoke and additional electric coils. This design can achieve the same field strength and field quality as conservative magnets, with only a small fraction of the electric power consumption, and a ca. 10% variability in the field amplitudes. In this paper, design and first optimization results of the magnets will be presented, which are a promising option for the new BESSY III facility, and an estimated reduction in total power consumption for the magnet lattice of up to 80%.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK001  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 01 July 2022
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THPOMS037 Ripple Pattern Formation on Silicon Carbide Surfaces by Low-Energy Ion-Beam Erosion radiation, experiment, cathode, ion-source 3045
 
  • D. Gupta, S. Aggarwal
    Kurukshetra University, Kurukshetra, India
  • R. Singhal
    Malviya Institute of Technology, Jaipur, India
  • G.R. Umapathy
    IUAC, New Delhi, India
 
  A versatile air insulated high current medium energy 200 kV Ion Accelerator has been running successfully at Ion Beam Centre, Kurukshetra University, India for carrying out multifarious experiments in material science and surface physics. Ion beam induced structures on the surfaces of semiconductors have potential applications in photonics, magnetic devices, photovoltaics, and surface-wetting tailoring etc. In this regard, silicon carbide (SiC) is a fascinating wide-band gap semiconductor for high-temperature, high-power and high-frequency applications. In the present work, fabrication of self-organized ripple patterns is carried out on the SiC surfaces using 80 keV Ar+ ions for different fluences at oblique incidence of 500. Studies demonstrate that ripple wavelength and amplitude, ordering and homogeneity of these patterns vary linearly with argon ion fluence. The ripples tend to align themselves parallel to the projection of the ion beam direction. The evolution of such surface structures is explained with the help of existing formalisms of coupling between surface topography and preferential sputtering.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS037  
About • Received ※ 20 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 18 June 2022
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THPOMS048 Challenge Based Innovation "Accelerators for the Environment" network, FEM, background 3077
 
  • N. Delerue
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • P. Burrows
    JAI, Oxford, United Kingdom
  • R. Holland, L. Rinolfi
    ESI, Archamps, France
  • E. Métral, M. Vretenar
    CERN, Meyrin, Switzerland
 
  Funding: This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No 101004730.
We present an initiative to foster new ideas about the applications of accelerators to the Environment. Called "Challenge Based Innovation" this initiative will gather four teams each of six master-level students each coming from different academic backgrounds. As part of the EU-funded I.FAST project (Innovation Fostering in Accelerator Science and Technology), they will gather during 10 days in Archamps near CERN to receive high level lectures on accelerators and the environment and to brainstorm on possible new applications of accelerators for the environment. At the end of the gathering, they will present their project at CERN to a jury made of experts.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS048  
About • Received ※ 09 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 20 June 2022 — Issue date ※ 01 July 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)