Keyword: focusing
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MOPAB040 Gain of Hard X-Ray Fel at 3 GeV and Required Parameters FEL, electron, undulator, laser 178
 
  • L.H. Yu
    BNL, Upton, New York, USA
  
  We develop a tool for the calculation to study the conditions for a hard x-ray FEL oscillator based on an electron beam in the medium energy range from 3 to 4.5 GeV. We show that the approach developed by K.J. Kim et al. for the small-signal low gain formula can be modified so that the gain can be derived without taking the "no focusing approximation" adopted in the approach so that a strong focusing can be applied. We also derive the formula to allow for the gain calculation of harmonic lasing. The gain in this formula can be cast in the form of a product of two factors with one of them only depends on the harmonic number, undulator period, and gap. Thus this factor can be used to show that it is favorable to use harmonic lasing to achieve hard x-ray FEL working in the medium energy range and in the small-signal low gain regime.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB040  
About • paper received ※ 09 May 2021       paper accepted ※ 26 May 2021       issue date ※ 10 August 2021  
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MOPAB139 High Resolution Imaging Design Using Permanent Magnet Quadrupoles at BNL UEM experiment, electron, quadrupole, target 485
 
  • G. Andonian, T.J. Campese, I.I. Gadjev, M. Ruelas
    RadiaBeam, Marina del Rey, California, USA
  • M.G. Fedurin, K. Kusche, X. Yang, Y. Zhu
    BNL, Upton, New York, USA
  • C.C. Hall
    RadiaSoft LLC, Boulder, Colorado, USA
  
  Ultrafast electron microscopy techniques have demonstrated the potential to reach very high combined spatio-temporal resolution. In order to achieve high resolution, strong focusing magnets must be used as the objective and projector lenses. In this paper, we discuss the design and development of a high-resolution objective lens for use in the BNL UEM. The objective lens is a quintuplet array of permanent magnet quadrupoles, which in sum, provide symmetric focusing, high magnification, and control of higher order aberration terms. The application and design for a proof-of-concept experiment using a calibrated slit for imaging are presented. The image resolution is monitored as a function of beam parameters (energy, energy spread, charge, bunch length, spot size), and quintuplet lens parameters (drifts between lenses).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB139  
About • paper received ※ 26 May 2021       paper accepted ※ 28 May 2021       issue date ※ 18 August 2021  
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MOPAB145 Acceleration and Focusing of Positron Bunch by Electron Bunch Wakefield in the Dielectric Waveguide Filled with Plasma plasma, positron, electron, wakefield 505
 
  • G.V. Sotnikov, R.R. Kniaziev, P.I. Markov
    NSC/KIPT, Kharkov, Ukraine
  
  Funding: The National Research Foundation of Ukraine, program "Leading and Young Scientists Research Support" (project # 2020.02/0299)
The results of the numerical PIC-simulation of accelerated positron bunch focusing in the plasma dielectric wakefield accelerator unit, filled with radially inhomogeneous plasma that has vacuum channel inside are presented. The Wakefield was created by drive electron bunch in quartz dielectric tube with external and internal diameters of 1.2 mm and 1.0 mm, respectively. The tube was embedded in cylindrical metal waveguide. The internal area of dielectric tube has been filled with different transverse density profiles of plasma: homogeneous density and inhomogeneous density created in capillary discharge. Drive bunch electrons energy was 5 GeV, drive bunch charge was 3 nC. The test positron bunch had the same parameters as the drive bunch except for the charge of 0.05 nC. Results of numerical PIC simulation have shown the possibility of simultaneous acceleration and focusing of test positron bunch in the wakefield excited by drive electron bunch. The dependence of transport and acceleration of positron bunch on size of vacuum channel is studied. 		 
poster icon Poster MOPAB145 [2.003 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB145  
About • paper received ※ 19 May 2021       paper accepted ※ 20 May 2021       issue date ※ 25 August 2021  
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MOPAB151 A Stable Drive Beam for High Gradient Dielectric Wakefield Acceleration wakefield, accelerating-gradient, acceleration, quadrupole 528
 
  • T.J. Overton, Y.M. Saveliev, G.X. Xia
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • T.J. Overton, G.X. Xia
    The University of Manchester, Manchester, United Kingdom
  • T.H. Pacey, Y.M. Saveliev
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  Funding: Science and Technology Funding Council (STFC) student grant.
A high accelerating gradient, with stable beam transport, is necessary for the next generation of particle accelerators. Dielectric wakefield accelerators are a potential solution to this problem. In these proceedings, we present simulation studies of electron bunches in the self-wake regime inside a planar dielectric structure. This is analogous to driving beams in a dielectric wakefield accelerator. The transverse and longitudinal wake fields are investigated for dielectric plate gaps, various transverse beam sizes, and longitudinal bunch profiles. The effects of these on the stability of drive bunches, and acceleration of a witness bunch, are discussed in the context of electron bunches that can be produced with conventional linac RF technology. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB151  
About • paper received ※ 13 May 2021       paper accepted ※ 07 June 2021       issue date ※ 24 August 2021  
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MOPAB154 Multi-Cell Accelerating Structure Driven by a Lens-Focused Picosecond THz Pulse laser, electron, timing, acceleration 537
 
  • S.P. Antipov, S.V. Kuzikov
    Euclid TechLabs, Solon, Ohio, USA
  • A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
  
  Recently, gradients on the order of 1 GV/m level have been obtained in a form of a single cycle (~1 ps) THz pulses produced by conversion of a high peak power laser radiation in nonlinear crystals (~1 mJ, 1 ps, up to 3% conversion efficiency). Such high-intensity radiation can be utilized for charged particle acceleration. However, these pulses are short in time (~1ps) and broadband, therefore a new accelerating structure type is required. In this paper, we propose a novel structure based on focusing of THz radiation in accelerating cell and stacking such cells to achieve a long-range interaction required for an efficient acceleration process. We present an example in which a 100 microJoule THz pulse produces a 600 keV energy gain in 5 mm long 10 cell accelerating structure for an ultra-relativistic electron. This design can be readily extended to non-relativistic particles. Such structure had been laser microfabricated and appropriate dimensions were achieved.  
poster icon Poster MOPAB154 [1.283 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB154  
About • paper received ※ 27 May 2021       paper accepted ※ 05 July 2021       issue date ※ 14 August 2021  
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MOPAB156 Wakefields and Transverse Bunch Dynamics Studies of a Plasma-Dielectric Accelerating Structure plasma, wakefield, GUI, electron 542
 
  • K. Galaydych, I.N. Onishchenko, G.V. Sotnikov
    NSC/KIPT, Kharkov, Ukraine
  
  Funding: The National Research Foundation of Ukraine, programme "Leading and Young Scientists Research Support" (grant agreement n. 2020.02/0299).
A theoretical investigation of a wakefield excitation in a plasma-dielectric accelerating structure by a drive electron bunch in the case of an off-axis bunch injection is carried out. The structure under investigation is a round dielectric-loaded metal waveguide with channel for the charged particles, filled with homogeneous cold plasma. In this paper we focus on the spatial distribution of the bunch-excited wakefield components, which act on both the drive and test bunches, and on transverse bunch dynamics. Dependence of the drive bunch propagation distance on its offset is studied. 		 
poster icon Poster MOPAB156 [2.042 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB156  
About • paper received ※ 19 May 2021       paper accepted ※ 18 June 2021       issue date ※ 14 August 2021  
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MOPAB165 Identical Focusing of Train of Relativistic Positron Gaussian Bunches in Plasma plasma, electron, positron, wakefield 565
 
  • D.S. Bondar
    KhNU, Kharkov, Ukraine
  • V.I. Maslov, I.N. Onishchenko
    NSC/KIPT, Kharkov, Ukraine
  
  Funding: The study is supported by the National Research Fundation of Ukraine under the program "Leading and Young Scientists Research Support" (project # 2020.02/0299).
Focusing of both electron and positron bunches in an electron-positron collider is necessary. The focusing mechanism in the plasma, in which all electron bunches are focused identically, has been proposed earlier*. This mechanism is considered for positron bunches by using simulation with LCODE**. Three types of lenses with different trains of cosine profile positron bunches are considered depending on the bunch length, the distance between bunches, and their charge. It has been shown that all positron bunches are focused identically at special parameters of the first positron bunch, wherein the middle of bunches are focused weaker than their fronts.
* V. I. Maslov et al. PAST. 3(2012) 159.
** K. V. Lotov, Phys. Plas. 5 (1998) 785. 		 
poster icon Poster MOPAB165 [2.272 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB165  
About • paper received ※ 17 May 2021       paper accepted ※ 20 May 2021       issue date ※ 17 August 2021  
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MOPAB168 Nanoplasmonic Accelerators Towards Tens of TeraVolts per Meter Gradients Using Nanomaterials electron, plasma, wakefield, experiment 574
 
  • A.A. Sahai, M. Golkowski, V. Harid
    CU Denver, Denver, Colorado, USA
  • C. Joshi
    UCLA, Los Angeles, California, USA
  • T.C. Katsouleas
    Duke ECE, Durham, North Carolina, USA
  • A. Latina, F. Zimmermann
    CERN, Geneva, Switzerland
  • J. Resta-López
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • P. Taborek
    UCI, Irvine, California, USA
  • A.G.R. Thomas
    University of Michigan, Ann Arbor, Michigan, USA
  
  Funding: University of Colorado Denver
Ultra-high gradients which are critical for future advances in high-energy physics, have so far relied on plasma and dielectric accelerating structures. While bulk crystals were predicted to offer unparalleled TV/m gradients that are at least two orders of magnitude higher than gaseous plasmas, crystal-based acceleration has not been realized in practice. We have developed the concept of nanoplasmonic crunch-in surface modes which utilizes the tunability of collective oscillations in nanomaterials to open up unprecedented tens of TV/m gradients. Particle beams interacting with nanomaterials that have vacuum-like core regions, experience minimal disruptive effects such as filamentation and collisions, while the beam-driven crunch-in modes sustain tens of TV/m gradients. Moreover, as the effective apertures for transverse and longitudinal crunch-in wakes are different, the limitation of traditional scaling of structure wakefields to smaller dimensions is significantly relaxed. The SLAC FACET-II experiment of the nano2WA collaboration will utilize ultra-short, high-current electron beams to excite nonlinear plasmonic modes and demonstrate this possibility.
* doi:10.1109/ACCESS.2021.3070798
** doi:10.1142/S0217751X19430097
*** indico.fnal.gov/event/19478/contributions/52561
**** indico.cern.ch/event/867535/contributions/3716404 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB168  
About • paper received ※ 11 May 2021       paper accepted ※ 08 June 2021       issue date ※ 20 August 2021  
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MOPAB178 Systematic Effects Limiting the Sensitivity of "Magic Energy" Proton EDM Rings proton, dipole, betatron, pick-up 602
 
  • C. Carli, M. Haj Tahar
    CERN, Geneva, Switzerland
  
  Proposals to measure a possible Electric Dipole Moment (EDM) of protons in an electro-static storage ring are studied by a world-wide community. The machine is operated at the so-called "magic energy" to satisfy the "frozen spin" condition such that, without imperfections and with the well known magnetic moment of the particle, the spin is always oriented parallel to the direction of movement. The effect of a finite EDM is a build-up of a vertical spin component. Any effect, other than a finite EDM, leading as well to a build-up of a vertical spin limits the sensitivity of the experiment. Such "systematic effects" are caused by machine imperfections, such as magnetic fields inside the magnetic shield surrounding the ring, and misalignments of electro-static elements or of the RF cavity. Operation of the machine with counter-rotating beams helps mitigating some of the effects. The most dangerous effects are those, which cannot be disentangled from an EDM by combining measurements from both counter-rotating beams, such as an average residual radial magnetic field penetrating the magnetic shield or a combination of magnetic fields and misalignments of electric elements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB178  
About • paper received ※ 18 May 2021       paper accepted ※ 17 June 2021       issue date ※ 20 August 2021  
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MOPAB210 High-Gradient Booster for Enhanced Proton Radiography at LANSCE linac, booster, cavity, proton 693
 
  • S.S. Kurennoy, Y.K. Batygin
    LANL, Los Alamos, New Mexico, USA
  
  Increasing energy of proton beam at LANSCE from 800 MeV to 3 GeV improves radiography resolution ~10 times. We propose accomplishing this energy boost with a compact cost-effective linac based on cryo-cooled normal conducting high-gradient RF accelerating structures. High-gradient structures exceeding 100 MV/m have been developed for electron acceleration and operate with short RF pulse lengths below 1 us. Though such parameters are unusual for typical proton linacs, they fit perfectly for proton radiography (pRad) applications. The pRad limits contiguous trains of beam micro-pulses to less than 80 ns to prevent blur in images. For a compact pRad booster at LANSCE, we develop a staged design: a short section to capture and compress the 800-MeV proton beam followed by the main high-gradient linac. Our beam dynamics study addresses the beam magnetic focusing and minimizing its energy spread, which are challenging in high-gradient structures but very important for successful pRad operation.  
poster icon Poster MOPAB210 [0.809 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB210  
About • paper received ※ 10 May 2021       paper accepted ※ 17 August 2021       issue date ※ 11 August 2021  
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MOPAB234 Analysis of the Chromatic Vertical Focusing Effect of Dipole Fringe Fields dipole, simulation, optics, closed-orbit 760
 
  • K. Hwang, C.E. Mitchell, R.D. Ryne
    LBNL, Berkeley, California, USA
  
  Funding: U.S. Department of Energy under Contract No. DE-AC02-05CH11231
There have been questions regarding the impact of the dipole fringe-field models (used by accelerator codes including ELEGANT and MADX) on vertical chromaticity. Here, we analyze the cause of the disagreement among codes and suggest a correction. 		 
poster icon Poster MOPAB234 [0.486 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB234  
About • paper received ※ 20 May 2021       paper accepted ※ 01 June 2021       issue date ※ 23 August 2021  
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MOPAB351 Using an RFQ to Transport Intense Heavy Ion Beams from an ECR Ion Source rfq, ECR, ion-source, gun 1093
 
  • G.O. Rodrigues
    IUAC, New Delhi, India
  • R.W. Hamm
    R&M Technical Enterprises, Pleasanton, California, USA
  
  In the transport of high intensity, heavy ions from an ECR ion source through a low energy beam transport (LEBT) section, space charge can limit the transmission. It has been proposed to use a Radio Frequency Quadrupole (RFQ) to efficiently address this problem. The stray magnetic field of the ECR ion source can be used to provide focusing against the space charge blow-up when using the Direct Plasma Injection Scheme (DPIS) developed for laser ion sources. The RFQ will focus and transport the injected beam, eliminating most of the charge states extracted from the ECR ion source. This narrowing of the charge state distribution is a filter, reducing the low energy beam transport problem, as well as the emittance growth for the desired beam. A combined extraction/matching system has been designed for direct injection into a 48.5 MHz RFQ for the production of 238U40+ (0.52 mA) and 209Bi30+ (1.047 mA) beams. The IGUN code has been used to design the injection directly into the RFQ. The RFQ design has been modified with a pre-buncher built into the vanes to narrow the transmitted charge state distribution as much as possible. The design details of this system will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB351  
About • paper received ※ 20 May 2021       paper accepted ※ 17 August 2021       issue date ※ 15 August 2021  
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MOPAB417 Preliminary Study of a Large Energy Acceptance FFA Beam Delivery System for Particle Therapy proton, optics, superconducting-magnet, radiation 1256
 
  • J.S.L. Yap, E.R. Higgins, S.L. Sheehy
    The University of Melbourne, Melbourne, Victoria, Australia
  
  The availability and use of ion beams for radiotherapy has grown significantly, led by technological developments to exploit the dosimetric advantages offered by charged particles. The benefits of particle therapy (PT) are well identified however its utilisation is still limited by high facility costs and technological challenges. A possibility to address both of these can be considered by improvements to the beam delivery system (BDS). Existing beamlines and gantries transport beams with a momentum range of ±1% and consequently, adjustments in depth or beam energy require all the magnetic fields to be changed. The speed to switch energies is a limiting constraint of the BDS and a determinant of the overall treatment time. A novel concept using fixed field alternating gradient (FFA) optics enables a large energy acceptance (LEA) as beams of varying energies can traverse the beamline at multiple physical positions given the same magnetic field. This presents the potential to provide faster, higher quality treatments at lower costs, with the capability to deliver advanced PT techniques such as multi-ion therapy. We explore the applicability and benefits of a LEA BDS.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB417  
About • paper received ※ 18 May 2021       paper accepted ※ 27 July 2021       issue date ※ 15 August 2021  
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TUXA07 Beam Dynamics Study in a Dual Energy Storage Ring for Ion Beam Cooling* storage-ring, cavity, electron, emittance 1290
 
  • B. Dhital, G.A. Krafft
    ODU, Norfolk, Virginia, USA
  • Y.S. Derbenev, D. Douglas, A. Hutton, G.A. Krafft, F. Lin, V.S. Morozov, Y. Zhang
    JLab, Newport News, Virginia, USA
  
  Funding: * Work supported by the U.S. Department of Energy, Office of Science, and Office of Nuclear Physics under Contracts DE-AC05-06OR23177 and DE-AC02-06CH11357. / Jefferson Lab EIC Fellowship2020.
A dual energy storage ring designed for beam cooling consists of two closed rings with significantly different energies: the cooling and damping rings. These two rings are connected by an energy recovering superconducting RF structure that provides the necessary energy difference. In our design, the RF acceleration has a main linac and harmonic cavities both running at crest that at first accelerates the beam from low energy EL to high energy EH and then decelerates the beam from EH to EL in the next pass. The purpose of the harmonic cavities is to extend the bunch length in a dual energy storage ring as such a longer bunch length may be very useful in a cooling application. Besides these cavities, a bunching cavity running on zero-crossing phase is used outside of the common beamline to provide the necessary longitudinal focusing for the system. In this paper, we present a preliminary lattice design along with the fundamental beam dynamics study in such a dual energy storage ring. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUXA07  
About • paper received ※ 19 May 2021       paper accepted ※ 07 June 2021       issue date ※ 28 August 2021  
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TUPAB028 Permanent Magnets Future Electron Ion Colliders at RHIC and LHeC linac, electron, permanent-magnet, collider 1401
 
  • D. Trbojevic, S.J. Brooks, V. Litvinenko, T. Roser
    BNL, Upton, New York, USA
  • G.H. Hoffstaetter
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • V. Litvinenko
    Stony Brook University, Stony Brook, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
We present a new ’green energy’ approach to the Energy Recovery Linac (ERL) and Recirculating Linac Accelerators (RLA) for the future Electron Ion Colliders (EIC) using single beam line made of very strong focusing combined function permanent magnets and the Fixed Field Alternating Linear Gradient (FFA-LG) principle. We are basing our design on recent very successful commissioning results of the Cornell University and Brookhaven National Laboratory ERL Test Accelerator. 		 
poster icon Poster TUPAB028 [2.720 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB028  
About • paper received ※ 17 May 2021       paper accepted ※ 27 May 2021       issue date ※ 30 August 2021  
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TUPAB102 A New 2nd Bunch Compression Chicane for the FLASH2020+ Project quadrupole, dipole, vacuum, FEL 1618
 
  • M. Vogt, J. Zemella
    DESY, Hamburg, Germany
  
  The first stage of the FLASH2020+ project is an upgrade of the FLASH injector beamline. Within this framework, the 2nd bunch compression chicane (BCC) will be completely redesigned. The old S-chicane will be replaced with a new C-chicane which is 3.5m shorter thereby generating space a new section for re-matching the beam from the injector into the linac. The new BCC will be equipped with quad/skew-quad units in both legs of the chicane to compensate correlations of the transverse degrees of freedom with the longitudinal ones. Since quadrupoles tend to have a circular bore, the chicane is designed with movable round vacuum chambers and movable dipoles for maintaining full flexibility in choosing the compression parameters. This article describes the technical details and introduces a thin-lens model of BCCs which allows analytical estimates on the effects of powering the quad/skew-quad units on optics parameters as well as estimates on the required strengths of these magnets in order to remove correlations of the magnitudes typically observed at FLASH.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB102  
About • paper received ※ 19 May 2021       paper accepted ※ 14 June 2021       issue date ※ 29 August 2021  
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TUPAB148 Optical-Period Bunch Trains to Resonantly Excite High Gradient Wakefields in the Quasi-Nonlinear Regime and the E-317 Experiment at FACET-II plasma, electron, wakefield, experiment 1736
 
  • P. Manwani, C.E. Hansel, N. Majernik, J.B. Rosenzweig, M. Yadav
    UCLA, Los Angeles, California, USA
  • M. Yadav
    The University of Liverpool, Liverpool, United Kingdom
  • M. Yadav
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: This work was performed with the support of the US Department of Energy under Contract No. DE-SC0009914 and National Science Foundation under Grant No. PHY-1549132
Periodic electron bunch trains spaced at the laser wavelength created via inverse free electron laser (IFEL) bunching can be used to resonantly excite plasmas in the quasi-nonlinear (QNL) regime. The excitation can produce plasma blowout conditions using very low emittance beams despite having a small charge per bunch. The resulting plasma density perturbation is extremely nonlinear locally, but preserves the resonant response of the plasma electrons at the plasma frequency. This excitation can produce plasma blowout conditions using very low emittance beams despite having a small charge per bunch. To match the resonance condition, the plasma wavelength has to be equal to the laser period of a few microns. This corresponds to a high density plasma resulting in extremely large wakefield amplitudes. Matching the beam into such a dense plasma requires an extremely short focusing beta function. We present the beam-plasma interaction using quasi-static particle-in-cell (PIC) simulations and discuss the micro-bunching and focusing mechanism required for this scheme which would be a precursor to the planned experiment, E-317, at SLAC’s FACET-II facility. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB148  
About • paper received ※ 20 May 2021       paper accepted ※ 08 July 2021       issue date ※ 19 August 2021  
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TUPAB190 Design and Simulation of the Extraction System of DC140 Cyclotron extraction, cyclotron, quadrupole, septum 1849
 
  • V.I. Lisov, A.A. Protasov, A.S. Zabanov
    JINR/FLNR, Moscow region, Russia
  • K. Gikal, G.G. Gulbekyan, I.A. Ivanenko, G.N. Ivanov, I.V. Kalagin, N.Yu. Kazarinov, S.V. Mitrofanov, N.F. Osipov, V.A. Semin
    JINR, Dubna, Moscow Region, Russia
  
  Flerov Laboratory of Nuclear Reaction of Joint Institute for Nuclear Research carries out the works under creating of FLNR JINR Irradiation Facility based on the cyclotron DC140. The facility is intended for SEE testing of microchip, for production of track membranes and for solving of applied physics problems. The DC140 cyclotron is intended for acceleration of heavy ions with mass-to-charge ratio A/Z within interval from 5 to 5.5 up to two fixed energies 2.124 and 4.8 MeV per unit mass. The intensity of the accelerated ions will be about 1 pmcA for light ions (A<86) and about 0.1 pmcA for heavier ions (A>132). The system based on four main elements - electrostatic deflector, focusing magnetic channel, Permanent Magnet Quadrupole lens and steering magnet is used in the DC140 cyclotron for extraction of the accelerated beam. The design and simulation of the beam extraction system from the DC140 cyclotron are presented in this report.  
poster icon Poster TUPAB190 [1.102 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB190  
About • paper received ※ 18 May 2021       paper accepted ※ 02 June 2021       issue date ※ 25 August 2021  
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TUPAB206 Matching of Intense Beam in Six-Dimensional Phase Space space-charge, emittance, framework, quadrupole 1897
 
  • Y.K. Batygin
    LANL, Los Alamos, New Mexico, USA
  
  Funding: Work supported by US DOE under contract 89233218CNA000001
Beam matching is a common technique that is routinely employed in accelerator design to minimize beam losses. Despite being widely used, a full theoretical understanding of beam matching in 6D phase space remains elusive. Here, we present an analytical treatment of 6D beam matching of a high-intensity beam onto an RF structure. We begin our analysis within the framework of a linear model, and apply the averaging method to attain a matched solution for a set of 3D beam envelope equations. We then consider the nonlinear regime, where the beam size is comparable with the separatrix size. Starting with a Hamiltonian analysis in 6D phase space, we attain a self-consistent beam profile and show that it is significantly different from the commonly used ellipsoidal shape. Subsequently, we analyze the special case of equilibrium with equal space charge depression between all degrees of freedom. A comparison of beam dynamics for equipartitioned, equal space charge depression, and equal emittances beams is given. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB206  
About • paper received ※ 14 May 2021       paper accepted ※ 28 May 2021       issue date ※ 24 August 2021  
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TUPAB209 The Particle Tracking Code Fixfield lattice, FFAG, quadrupole, acceleration 1905
 
  • J.-B. Lagrange
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  
  FixField is a code developed to track particles in Fixed Field alternating gradient Accelerators (FFAs). This paper discusses the structure and features of the code.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB209  
About • paper received ※ 19 May 2021       paper accepted ※ 02 July 2021       issue date ※ 25 August 2021  
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TUPAB215 Novel Non-Linear Particle Tracking Approach Employing Lie Algebraic Theory in the TensorFlow Environment quadrupole, network, lattice, operation 1920
 
  • J. Frank, M. Arlandoo, P. Goslawski, J. Li, T. Mertens, M. Ries, L. Vera Ramirez
    HZB, Berlin, Germany
  
  With this paper we present first results for encoding Lie transformations as computational graphs in Tensorflow that are used as layers in a neural network. By implementing a recursive differentiation scheme and employing Lie algebraic arguments we were able to reproduce the diagrams for well known lattice configurations. We track through simple optical lattices that are encountered as the main constituents of accelerators and demonstrate the flexibility and modularity our approach offers. The neural network can represent the optical lattice with predefined coefficients allowing for particle tracking for beam dynamics or can learn from experimental data to fine-tune beam optics.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB215  
About • paper received ※ 12 May 2021       paper accepted ※ 31 August 2021       issue date ※ 21 August 2021  
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TUPAB225 3D Magnetic Field Analysis of LHC Final Focus Quadrupoles with Beam Screen quadrupole, octupole, HOM, database 1952
 
  • T. Pugnat, B. Dalena, C. Lorin
    CEA-IRFU, Gif-sur-Yvette, France
  • S. Bagnis
    CEA-DRF-IRFU, France
  
  During the LHC commissioning, a discrepancy in the non-linear corrector strengths between the model and the beam-based values has been observed*. This has motivated the reconstruction of the 3D finite element model for the LHC final focusing MQXA type magnet. The longitudinal higher orders magnetic field pseudo-harmonics are computed taking into account ovalization of the magnet, interconnections design, and beam screens. The effect of this 3D field on the computation of the nonlinear correctors is evaluated and compared with beam-based corrector values.
*E. H. Maclean et al., "New approach to LHC optics commissioning for the nonlinear era", Phys. Rev. Acc. B, vol. 22, pp. 061004, June 2019. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB225  
About • paper received ※ 18 May 2021       paper accepted ※ 08 July 2021       issue date ※ 12 August 2021  
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TUPAB250 Axicon-Based Concentrator for Cherenkov Radiation target, radiation, diagnostics, simulation 2036
 
  • S.N. Galyamin, A.V. Tyukhtin
    Saint Petersburg State University, Saint Petersburg, Russia
  
  Funding: Work supported by Russian Science Foundation (Grant No. 18-72-10137).
We propose a new type of axisymmetric dielectric target - an "axicon-based concentrator" - which effectively concentrates generated Cherenkov radiation (CR) into a small vicinity of a focus point. It consists of two "glued" bodies of revolution: a hollow axicon and a hollow "lens." A theoretical investigation of the radiation field produced by a charge moving through the discussed radiator is performed for the general case where a charge trajectory is shifted with respect to the structure axis. The idea of a dielectric target with a specific profile of the outer surface and suitable analytical methods were presented and developed in our preceding papers *, **. An essential advantage of the current version of the device is that it allows the efficient concentration of CR energy from relativistic particles, making this device extremely prospective for various applications such as beam-driven THz sources and bunch diagnostic systems.
* S.N. Galyamin et al., Phys. Rev. Accel. Beams 22, 083001 (2019); 22, 109901 (2019).
** A.V. Tyukhtin et al., Phys. Rev. A 102, 053514 (2020). 		 
poster icon Poster TUPAB250 [1.255 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB250  
About • paper received ※ 24 May 2021       paper accepted ※ 21 June 2021       issue date ※ 12 August 2021  
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TUPAB280 Quantum Gas Jet Scanner Based Beam Profile Monitors electron, injection, beam-diagnostic, diagnostics 2128
 
  • N. Kumar, A. Salehilashkajani, C.P. Welsch, H.D. Zhang
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • N. Kumar, A. Salehilashkajani, C.P. Welsch, H.D. Zhang
    The University of Liverpool, Liverpool, United Kingdom
  
  Funding: This work is supported by the HL-LHC-UK project funded by STFC and CERN and the STFC Cockcroft core grant No. ST/G008248/1.
A quantum gas jet scanner-based beam profile monitor is under development at the Cockcroft Institute (CI), the UK for beam diagnostics based on the principle of ionization detection induced in a quantum gas jet interacting with an ionizing primary beam that shall be characterized. It promises superior position resolution and high signal intensity resulting from a strongly focused quantum gas jet. In order to achieve the gas jet with a diameter of less than 100 µm, a novel focusing method exploiting the quantum wave function of the neutral gas atoms, generate an interference pattern with a single maximum acting as an ultra-thin gas jet. An ‘atom sieve’ has been designed for generating the interference pattern, applying the principle of a photon sieve. It will be analogous to a mechanical wire scanner though with a minimal interception. The idea of moving a quantum gas jet through the beam is proposed for transverse profiling. This contribution provides a general overview of the design, working principle, the results obtained from initial measurements carried out at CI and University of Bergen (Norway), for designing the same and possible methods for optimizing the scanner’s design. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB280  
About • paper received ※ 19 May 2021       paper accepted ※ 31 May 2021       issue date ※ 25 August 2021  
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TUPAB313 Arrangement Optimization of Quadrupoles and Correctors for Beam Alignment quadrupole, alignment, electron, FEL 2221
 
  • L. Xu, Q.M. Zhang
    Xi’an Jiaotong University, People’s Republic of China
  • H.X. Deng
    SARI-CAS, Pudong, Shanghai, People’s Republic of China
  • N. Huang
    UCAS, Beijing, People’s Republic of China
  • N. Huang
    SINAP, Shanghai, People’s Republic of China
  
  In the X-ray free-electron laser (XFEL), the alignment and stability of beam orbit have a great impact on power and qualities of the generated X-ray pulses. Currently, the beam-based alignment (BBA) is the most widely used technique in beam alignment. In order to find the best arrangement of quadrupoles and correctors, a mathematical model is established based on the transmission matrix method. With this model, several simple arrangements of quadrupoles and correctors are selected to simulate the beam alignment process. It is found that when two correctors adjust two quadrupoles, the beam can pass through the center of quadrupoles approximately collimated.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB313  
About • paper received ※ 16 May 2021       paper accepted ※ 31 August 2021       issue date ※ 16 August 2021  
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TUPAB408 A Novel Automatic Focusing System for the Production of Radioisotopes for Theranostics target, cyclotron, detector, radiation 2480
 
  • P. Häffner, C. Belver-Aguilar, S. Braccini, P. Casolaro, G. Dellepiane, I. Mateu, P. Scampoli, M. Schmid
    AEC, Bern, Switzerland
  • P. Scampoli
    Naples University Federico II, Napoli, Italy
  
  Funding: This research was partially funded by the Swiss National Science Foundation (SNSF). Grants:200021175749, CRSII5180352, CR23I2156852.
A research program on the production of novel radioisotopes for theranostics is ongoing at the 18 MeV Bern medical cyclotron laboratory equipped with a solid target station. Targets are made of rare and expensive isotope enriched materials in form of compressed 6 mm diameter pellets. The irradiation of such a small target is challenging. A specific capsule has been developed made of two aluminum halves kept together by permanent magnets. Since the beam extracted from a medical cyclotron is about 12 mm FWHM, an automatic compact focusing system was conceived and constructed to optimise the irradiation procedure. It is based on a 0.5 m long magnetic system, embedding two quadrupoles and two steering magnets, and a non-destructive beam monitoring detector located in front of the target. The profiles measured by the detector are elaborated by a specific software that, through a feedback optimisation algorithm, acts on the magnets and keeps the beam focused on target. Being about 1 m long, it can be installed in any existing medical cyclotron facility. The design of the first prototype together with the results of the first beam tests are presented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB408  
About • paper received ※ 17 May 2021       paper accepted ※ 24 June 2021       issue date ※ 19 August 2021  
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WEXB06 Development of an APF IH-DTL in the J-PARC Muon g-2/EDM Experiment DTL, linac, cavity, experiment 2544
 
  • Y. Nakazawa, H. Iinuma
    Ibaraki University, Hitachi, Ibaraki, Japan
  • E. Cicek, N. Kawamura, T. Mibe, M. Yoshida
    KEK, Ibaraki, Japan
  • N. Hayashizaki
    RLNR, Tokyo, Japan
  • Y. Iwata
    NIRS, Chiba-shi, Japan
  • R. Kitamura, Y. Kondo, T. Morishita
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • M. Otani, N. Saito
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • Y. Sue, K. Sumi, M. Yotsuzuka
    Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
  • Y. Takeuchi
    Kyushu University, Fukuoka, Japan
  • T. Yamazaki
    KEK, Tokai Branch, Tokai, Naka, Ibaraki, Japan
  • H.Y. Yasuda
    University of Tokyo, Tokyo, Japan
  
  An inter-digital H-mode drift-tube linac (IH-DTL) is under development in a muon linac at the J-PARC muon g-2/EDM experiment. It accelerates muons from 0.34 MeV to 4.3 MeV at an operating frequency of 324 MHz. The cavity can be miniaturized by introducing the alternative phase focusing (APF) method that enables transverse focusing only with an E-field. The APF IH-DTL cavity was modeled by a three-dimensional field analysis, and the beam dynamics were evaluated numerically. The beam emittance was calculated as 0.316pi and 0.189pi mm mrad in the horizontal and vertical directions, respectively. It satisfies the experimental requirement. Actually, the field error due to the fabrication errors and thermal expansion during operation causes an emittance growth. It was evaluated that the optimized tuners can suppress the emittance growth to less than 10%. In this paper, the detailed design of the APF IH-DTL including the tuner will be reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXB06  
About • paper received ※ 19 May 2021       paper accepted ※ 29 July 2021       issue date ※ 20 August 2021  
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WEXC05 First Results Operating a Long-Period EPU in Universal Mode at the Canadian Light Source polarization, photon, undulator, injection 2566
 
  • W.A. Wurtz, C.K. Baribeau, D. Bertwistle, M.J. Sigrist
    CLS, Saskatoon, Saskatchewan, Canada
  
  The Quantum Materials Spectroscopy Centre beamline at the Canadian Light Source (CLS) requires photons with energies as low as 15 eV with circular polarization at the end station. This energy range is accomplished on the 2.9 GeV CLS storage ring using an elliptically polarizing undulator (EPU) with a 180 mm period, which we call EPU180. In order to realize circular polarized photons at the end station with this low energy, we must overcome two technical issues. First, the beamline optics distort the polarization of the light, so we compensate by providing light with a flattened, tilted polarization ellipse at the source point - a mode of operation known as universal mode. Second, the device has a strong effect on the electron beam due to dynamic focusing and is capable of reducing the injection efficiency to zero. We overcome this non-linear dynamic focusing using current strips adhered to the vacuum chamber. In this report, we present the first results with operating EPU180 in universal mode and we recover the dynamic aperture using the current strips.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXC05  
About • paper received ※ 13 May 2021       paper accepted ※ 05 July 2021       issue date ※ 11 August 2021  
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WEPAB044 Status of VHEE Radiotherapy Related Studies at the CLEAR User Facility at CERN electron, experiment, radiation, linac 2704
 
  • R. Corsini, W. Farabolini, A. Gilardi
    CERN, Geneva, Switzerland
  • L.A. Dyks, P. Korysko
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
  • W. Farabolini
    CEA-DRF-IRFU, France
  • A. Gilardi
    University of Napoli Federico II, Napoli, Italy
  • K.N. Sjobak
    University of Oslo, Oslo, Norway
  
  Despite the increase in interest in using Very High Energy Electron (VHEE) beams for cancer radiotherapy many unanswered questions in its development remain. The use of test facilities will be an essential tool used to solve these issues. The 200 MeV electron beam from the CERN Linear Accelerator for Research (CLEAR) has been used extensively, in collaboration with several research institutes, to perform dosimetry studies and explore potential applications of VHEE beams to radiotherapy, including the exploitation of the so called FLASH effect. In this paper, we present an overview of past studies with emphasis on the more recent results. We describe methods, techniques and equipment developed at CERN in this framework, and give an outlook on future activities.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB044  
About • paper received ※ 18 May 2021       paper accepted ※ 23 June 2021       issue date ※ 27 August 2021  
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WEPAB089 Conceptual Design of Booster Synchrotron for Siam Photon Source II booster, synchrotron, lattice, dipole 2795
 
  • S. Krainara, S. Klinkhieo, P. Klysubun, T. Pulampong, P. Sudmuang
    SLRI, Nakhon Ratchasima, Thailand
  
  Funding: Synchrotron Light Research Institute (Public organization)
A project on a 3.0 GeV Siam Photon Source II (SPS-II) has been started. The storage ring of SPS-II was designed to obtain an electron beam with a low-emittance below 1 nm-rad. The SPS-II injector mainly consists of a 150 MeV linac and a full-energy booster synchrotron. The booster synchrotron will be installed in the same tunnel as the storage ring, with a total circumference of 304.829 meters. The proposed lattice of the booster contains 40 modified FODO cells with combined function magnets. This lattice achieves a small beam emittance less than 10 nm-rad at 3 GeV, which can provide a high injection efficiency for top-up operation. The conceptual design for SPS-II booster synchrotron is presented in this work. 		 
poster icon Poster WEPAB089 [1.187 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB089  
About • paper received ※ 19 May 2021       paper accepted ※ 08 June 2021       issue date ※ 24 August 2021  
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WEPAB131 Magnetic Tuning and Installation Modifications of U48 Undulator for the Delhi Light Source (DLS) undulator, electron, controls, vacuum 2918
 
  • M. Tischer, P. Neumann, A. Schöps, P. Vagin, T. Vielitz, T. Wohlenberg
    DESY, Hamburg, Germany
  • M. Aggarwal, R.N. Dutt, S. Ghosh, J. Karmakar, S. Sahu
    IUAC, New Delhi, India
  • J. Bahrdt, E.C.M. Rial
    HZB, Berlin, Germany
  
  A compact THz radiation facility based on the principle of a pre-bunched Free Electron Laser, called Delhi Light Source (DLS) is at the final stage of commissioning at IUAC, New Delhi, India. For generation of THz radiation in DLS, an undulator with period length of 48 mm (U48), built by HZB and refurbished at DESY will be used. The magnetic tuning and the field measurements have been done on the U48 along with the design and installation of correction coils at the entrance/exit of the U48. In addition, horizontal and vertical ambient field correction coils were integrated into the magnet girders. A quadrupole correction coil along the vacuum chamber in order to mitigate the defocusing effect of the U48 on the electron beam has been designed. The current through all coils has been adjusted as a function of the gap by the new control system designed for the U48. In addition, an extruded aluminium vacuum chamber was designed and fabricated and will be aligned with the the undulator soon.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB131  
About • paper received ※ 19 May 2021       paper accepted ※ 05 July 2021       issue date ※ 11 August 2021  
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WEPAB140 Second Beam Test and Numerical Investigation of the Imperial College Plasma (Gabor) Lens Prototype plasma, electron, proton, laser 2943
 
  • T.S. Dascalu
    Imperial College London, London, United Kingdom
  • R. Bingham, C.G. Whyte
    USTRAT/SUPA, Glasgow, United Kingdom
  • C.L. Cheung, H.T. Lau, K.R. Long, T. Nonnenmacher, J.K. Pozimski
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  
  Funding: STFC through the Imperial Impact Acceleration Account
The design of the Laser-hybrid Accelerator for Radiobiological Applications (LhARA) is based on a series of plasma lenses to capture, focus, and select the energy of the ions produced in the laser-target interaction. A second beam test of the first plasma lens prototype, built at the Imperial College London, took place in October 2017 at the Ion Beam Centre of the University of Surrey. 1.4 MeV proton pencil beams were imaged 0.67m downstream of the lens on a scintillator screen over a wide range of settings. On top of the focusing effect, the electron plasma converted pencil beams into rings. The intensity of each ring shows a different degree of modulation along its circumference. Analysis of the results indicates non-uniformity and an off-axis rotation of the electron plasma. The effect on the beam is presented and compared to the results of a simulation of the plasma dynamics and proton beam transport through the lens. A particle-tracking code was used to study the impact of plasma instabilities on the focusing forces produced by the lens. The m = 1 diocotron instability was associated with the formation of rings from the pencil beams. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB140  
About • paper received ※ 19 May 2021       paper accepted ※ 29 August 2021       issue date ※ 18 August 2021  
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WEPAB203 RFQ Beam Dynamics Optimization Using Machine Learning rfq, simulation, network, quadrupole 3100
 
  • D. Koser, J.M. Conrad, L.H. Waites, D. Winklehner
    MIT, Cambridge, Massachusetts, USA
  • A. Adelmann, M. Frey, S. Mayani
    PSI, Villigen PSI, Switzerland
  
  To efficiently inject a high-current H2+ beam into the 60 MeV driver cyclotron for the proposed IsoDAR project in neutrino physics, a novel direct-injection scheme is planned to be implemented using a compact radio-frequency quadrupole (RFQ) as a pre-buncher, being partially inserted into the cyclotron yoke. To optimize the RFQ beam dynamics design, machine learning approaches were investigated for creating a surrogate model of the RFQ. The required sample datasets are generated by standard beam dynamics simulation tools like PARMTEQM and RFQGen or more sophisticated PIC simulations. By reducing the computational complexity of multi-objective optimization problems, surrogate models allow to perform sensitivity studies and an optimization of the crucial RFQ beam output parameters like transmission and emittances. The time to solution might be reduced by up to several orders of magnitude. Here we discuss different methods of surrogate model creation (polynomial chaos expansion and neural networks) and identify present limitations of surrogate model accuracy.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB203  
About • paper received ※ 20 May 2021       paper accepted ※ 01 July 2021       issue date ※ 30 August 2021  
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WEPAB212 Physics Studies for the LBNF Graphite Target Design target, detector, simulation, proton 3123
 
  • J.J. Back
    University of Warwick, Coventry, United Kingdom
  
  We present the simulated physics performance of the Long-Baseline Neutrino Facility (LBNF) graphite target that is being designed by the RAL High Power Targets Group for the Deep Underground Neutrino Experiment (DUNE). We first compare three conceptual cylindrical target design options as a function of target length (up to 2.2 m): downstream supported, two individual targets and an upstream-supported cantilever. Choosing the cantilever design as the baseline, we show the effect of widening the upstream inner conductor of the first focusing horn to provide extra space for supporting the target. We also give estimates of the expected performance of the 1.5 m prototype and 1.8 m production cantilevered targets. Furthermore, we show the effects of the main engineering updates made to the other two focusing horns since the DUNE TDR.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB212  
About • paper received ※ 17 May 2021       paper accepted ※ 05 July 2021       issue date ※ 26 August 2021  
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WEPAB248 Kurth Vlasov-Poisson Solution for a Beam in the Presence of Time-Dependent Isotropic Focusing emittance, space-charge, simulation, proton 3213
 
  • C.E. Mitchell, K. Hwang, R.D. Ryne
    LBNL, Berkeley, California, USA
  
  Funding: This work was supported by the Director, Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The well-known K-V distribution provides an exact solution of the self-consistent Vlasov-Poisson system describing an unbunched charged particle beam with nonzero temperature in the presence of time-dependent linear transverse focusing. We describe a lesser-known exact solution of the Vlasov-Poisson system that is based on the work of Kurth in stellar dynamics. Unlike the K-V distribution, the Kurth distribution is a true function of the phase space variables, and the solution may be constructed on either the 4D or 6D phase space, for the special case of isotropic linear focusing. Numerical studies are performed for benchmarking simulation codes, and the stability properties of a 4D Kurth distribution are compared with those of a K-V distribution. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB248  
About • paper received ※ 19 May 2021       paper accepted ※ 14 July 2021       issue date ※ 02 September 2021  
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WEPAB254 Design of a 10 MeV Beamline at the Upgraded Injector Test Facility for e-Beam Irradiation electron, radiation, solenoid, cavity 3232
 
  • X. Li, H. Baumgart, G. Ciovati
    ODU, Norfolk, Virginia, USA
  • G. Ciovati, F.E. Hannon, S. Wang
    JLab, Newport News, Virginia, USA
  
  Funding: Jefferson lab LDRD.
Electron beam irradiation near 10 MeV is suitable for wastewater treatment. The Upgraded Injector Test Facility (UITF) at Jefferson Lab is a CW superconducting linear accelerator capable of providing an electron beam of energy up to 10 MeV and up to 100 µA current. This contribution presents the beam transport simulations for a beamline to be used for the irradiation of wastewater samples at the UITF. The simulations were done using the code General Particle Tracer with the goal of obtaining an 8 MeV electron beam of radius (3-σ) of ~2.4 cm. The achieved energy spread is ~74.5 keV. The space charge effects were investigated when the bunch charge is varied to be up to 1000 times and the results showed that they do not affect the beam quality significantly. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB254  
About • paper received ※ 20 May 2021       paper accepted ※ 25 June 2021       issue date ※ 13 August 2021  
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WEPAB258 Beam Dynamics Design of a 162.5 MHz Superconducting RFQ Accelerator rfq, emittance, cavity, accelerating-gradient 3248
 
  • Ying. Xia, H.P. Li, Y.R. Lu, Q.Y. Tan, Z. Wang
    PKU, Beijing, People’s Republic of China
  • Y.R. Lu
    IAP, Frankfurt am Main, Germany
  
  Superconducting(SC) RFQ has lower power consumption, larger aperture and higher accelerating gradient than room temperature RFQ. We plan to design a 162.5MHz SC RFQ to accelerate the 30 mA proton beams from 35 keV to 2.5 MeV, which will be used as a neutron source for BNCT and neutron imaging project. At an inter-vane voltage of 180kV, the beam dynamics design was carried out with acceptable peak surface electric field, high transmission efficiency, and relatively short cavity length.  
poster icon Poster WEPAB258 [1.251 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB258  
About • paper received ※ 17 May 2021       paper accepted ※ 06 July 2021       issue date ※ 14 August 2021  
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WEPAB263 Complex Unit Lattice Cell for Low-Emittance Synchrotrons lattice, sextupole, emittance, synchrotron 3254
 
  • Z.L. Ren, Z.H. Bai, J.J. Tan, L. Wang, H. Xu, P.H. Yang
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
  
  To reach the real diffraction-limited emittance, it is generally required to increase the number of bends in multi-bend achromat (MBA) lattices that are used in the designs of fourth-generation synchrotron light sources. For an MBA lattice with distributed chromatic correction, more bends mean much tighter space and much stronger magnets. Inspired by the hybrid MBA lattice concept, in this paper we propose a new lattice concept called complex unit lattice cell, which can save space and reduce magnet strengths. A 17BA lattice based on the complex unit cell concept is designed for a 3 GeV synchrotron light source with a circumference of 537.6 m, which reaches a natural emittance of about 21 pm·rad. Comparison is also made between this 17BA lattice and the 17BA lattice with distributed chromatic correction to demonstrate the merit of the complex unit cell concept.  
poster icon Poster WEPAB263 [1.279 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB263  
About • paper received ※ 16 May 2021       paper accepted ※ 02 July 2021       issue date ※ 12 August 2021  
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WEPAB277 Transverse Emittance Change and Canonical Angular Momentum Growth in MICE ‘Solenoid Mode’ with Muon Ionization Cooling solenoid, emittance, detector, collider 3289
 
  • T.W. Lord
    University of Warwick, Coventry, United Kingdom
  
  Emittance reduction of muon beams is an important requirement in the design of a Neutrino Factory or Muon Collider. Ionization cooling, whereby beam emittance is reduced by passing a beam through an energy-absorbing material, requires tight focusing in the transverse plane which is achieved in many designs using solenoid focusing. In solenoid focusing, the beam acquires kinetic angular momentum due to the radial field in the solenoid fringe. Cooling in ‘flip’ mode, where the beam-focusing solenoid field changes polarity at the absorber, has already been demonstrated in the Muon Ionization Cooling Experiment (MICE). In this mode the absorber is near to the field flip, so the kinetic angular momentum is zero at the absorber. ‘Solenoid mode’ cooling, where the field polarity does not change across the absorber leading to a beam crossing the absorber with significant kinetic angular momentum, has been considered for the final section of the muon collider design due to potentially stronger focussing that it enables. In this paper, we present the performance of MICE in ‘solenoid mode’.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB277  
About • paper received ※ 19 May 2021       paper accepted ※ 06 July 2021       issue date ※ 12 August 2021  
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WEPAB383 An Evolutionary Algorithm Approach to Multi-Pass ERL Optics Design linac, optics, quadrupole, simulation 3610
 
  • I. Neththikumara, T. Satogata
    ODU, Norfolk, Virginia, USA
  • R.M. Bodenstein, S.A. Bogacz, T. Satogata
    JLab, Newport News, Virginia, USA
  • A. Vandenhoeke
    ULB, Bruxelles, Belgium
  
  Funding: This material is based upon work supported by the U.S. Department of Energy under contract DE-AC05-06OR23177.
An Energy Recovery Experiment at CEBAF (ER@CEBAF) is aimed at demonstrating high energy, low current, multi-pass energy recovery at the existing 12 GeV CEBAF accelerator. The beam break-up instability, limiting the maximum beam current, can be controlled through minimizing beta functions for the lowest energy pass, which gives a preference to strongly focusing optics, e.g. a semi-periodic FODO lattice. On the other hand, one needs to limit beta function excursions, caused by under focusing, at the higher energy passes, which in turn favors weakly focusing linac optics. Balancing both effects is the main objective of proposed multi-pass linac optics optimization. Here, we discuss an optics design process for ER@CEBAF transverse optics using a genetic algorithm. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB383  
About • paper received ※ 19 May 2021       paper accepted ※ 02 July 2021       issue date ※ 15 August 2021  
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THPAB071 Physics Goals of DWA Experiments at FACET-II experiment, wakefield, quadrupole, acceleration 3922
 
  • J.B. Rosenzweig, H.S. Ancelin, G. Andonian, A. Fukasawa, C.E. Hansel, G.E. Lawler, W.J. Lynn, N. Majernik, J.I. Mann, P. Manwani, Y. Sakai, O. Williams, M. Yadav
    UCLA, Los Angeles, California, USA
  • S.V. Baryshev
    Michigan State University, East Lansing, Michigan, USA
  • S. Baturin
    Northern Illinois University, DeKalb, Illinois, USA
  • M.J. Hogan, B.D. O’Shea, D.W. Storey, V. Yakimenko
    SLAC, Menlo Park, California, USA
  
  Funding: This work supported by DOE HEP Grant DE-SC0009914,
The dielectric wakefield acceleration (DWA) program at FACET produced a multitude of new physics results that range from GeV/m acceleration to the discovery of high field-induced conductivity in THz waves, and beyond, to a demonstration of positron-driven wakes. Here we review the rich program now developing in the DWA experiments at FACET-II. With increases in beam quality, a key feature of this program is extended interaction lengths, near 0.5 m, permitting GeV-class acceleration. Detailed physics studies in this context include beam breakup and its control through the exploitation of DWA structure symmetry. The next step in understanding DWA limits requires the exploration of new materials with low loss tangent, large bandgap, and improved thermal characteristics. Advanced structures with photonic features for mode confinement and exclusion of the field from the dielectric, as well as quasi-optical handling of coherent Cerenkov signals is discussed. Use of DWA for laser-based injection and advanced temporal diagnostics is examined. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB071  
About • paper received ※ 25 May 2021       paper accepted ※ 28 July 2021       issue date ※ 22 August 2021  
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THPAB121 Plasma Muon Beam Cooling for HEP plasma, cavity, simulation, emittance 3999
 
  • M.A. Cummings, R.J. Abrams, R.P. Johnson, S.A. Kahn, T.J. Roberts
    Muons, Inc, Illinois, USA
  • V.S. Morozov, A.V. Sy
    JLab, Newport News, Virginia, USA
  • K. Yonehara
    Fermilab, Batavia, Illinois, USA
  
  Ionization cooling has the potential to shrink the phase space of a muon beam by a factor of 106 within the muons’ short lifetime (2.2 µs) because the collision frequency in a cooling medium is extremely high compared to conventional beam cooling methods. It has been realized that ionization cooling inherently produces a plasma of free electrons inside the absorber material, and this plasma can have an important effect on the muon beam. In particular, under the right circumstances, it can both improve the rate of cooling and reduce the equilibrium emittance of the beam. This has the potential to improve the performance of muon facilities based on muon cooling; in particular a future muon collider. We describe how this project will integrate Plasma muon beam cooling into both the basic Helical Cooling Channel (HCC) and extreme Parametric-resonance Ionization Cooling (PIC) techniques. This potentially whole new approach to muon cooling has exciting prospects for significantly reduced muon beam emittance.  
poster icon Poster THPAB121 [1.214 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB121  
About • paper received ※ 19 May 2021       paper accepted ※ 12 July 2021       issue date ※ 11 August 2021  
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THPAB124 Application of the FFA Concept to a Muon Collider Complex quadrupole, collider, lattice, optics 4006
 
  • S. Machida, J.-B. Lagrange
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • M.E. Topp-Mugglestone
    JAI, Oxford, United Kingdom
  
  Muon collider complex is one of the places where the concept of fixed field alternating gradient (FFA) optics can be applied with great benefits. Vertical excursion FFA (vFFA) provides the isochronous condition for the ultra-relativistic muon beams after pre-acceleration. Together with the fixed transverse tune, it will be an ideal accelerator of short-lived muon beams with no time variation of magnetic fields and RF frequency. Novel collider ring optics is a design based on skew quadrupole after extracting essential functions from vFFA. That enables control of the momentum compaction factor. Neutrinos from the continuing decay of muons are spread out with orbit wiggling in the vertical direction as well as horizontal. The paper discusses the underline principle and describes some design examples.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB124  
About • paper received ※ 19 May 2021       paper accepted ※ 02 August 2021       issue date ※ 28 August 2021  
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THPAB155 Strong Quadrupole Wakefield Based Focusing in Dielectric Wakefield Accelerators wakefield, controls, simulation, electron 4059
 
  • W.J. Lynn, G. Andonian, N. Majernik, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  
  Funding: Grant number: DOE HEP Grants DE-SC0017648, DE-SC0009914, and National Science Foundation Grant No. PHY-1549132.
We propose here to exploit the quadrupole wakefields in an alternating symmetry slab-based dielectric wakefield accelerator (DWA) to produce second-order focusing. The resultant focusing is found to be strongly dependent on longitudinal position in the bunch. We analyze this effect with analytical estimates and electromagnetic PIC simulations. We examine the use of this scenario to induce beam stability in very high gradient DWA, with positive implications for applications in linear colliders and free-electron lasers. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB155  
About • paper received ※ 20 May 2021       paper accepted ※ 27 July 2021       issue date ※ 19 August 2021  
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THPAB197 Enhancing Efficiency of Multi-Objective Neural-Network-Assisted Nonlinear Dynamics Lattice Optimization via 1-D Aperture Objectives & Objective Focusing lattice, network, simulation, storage-ring 4156
 
  • Y. Hidaka, D.A. Hidas, F. Plassard, T.V. Shaftan, G.M. Wang
    BNL, Upton, New York, USA
  
  Funding: This work is supported by U.S. DOE under Contract No. DE-SC0012704.
Mutli-objective optimizers such as multi-objective genetic algorithm (MOGA) have been quite popular in discovering desirable lattice solutions for accelerators. However, even these successful algorithms can become ineffective as the dimension and range of the search space increase due to exponential growth in the amount of exploration required to find global optima. This difficulty is even more exacerbated by the resource-intensive and time-consuming tendency for the evaluations of nonlinear beam dynamics. Lately the use of surrogate models based on neural network has been drawing attention to alleviate this problem. Following this trend, to further enhance the efficiency of nonlinear lattice optimization for storage rings, we propose to replace typically used objectives with those that are less time-consuming and to focus on a single objective constructed from multiple objectives, which can maximize utilization of the trained models through local optimization and objective gradient extraction. We demonstrate these enhancements using a NSLS-II upgrade lattice candidate as an example. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB197  
About • paper received ※ 20 May 2021       paper accepted ※ 23 June 2021       issue date ※ 10 August 2021  
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THPAB224 The Correction of Time-Dependent Tune Shift by Harmonic Injection injection, quadrupole, simulation, neutron 4234
 
  • X.H. Lu
    IHEP CSNS, Guangdong Province, People’s Republic of China
  • J. Chen, S. Wang, S.Y. Xu
    IHEP, Beijing, People’s Republic of China
  
  In the Rapid Cycling Synchrotron(RCS) of China Spallation Neutron Source(CSNS), transverse painting injection is employed to suppress the space-charge effects. The beta-beating caused by edge focusing of the injection bump magnets leads to tune shift. A new method based on the harmonic injection is firstly introduced to correct the time-dependent tune shift caused by the edge focusing effect of the chicane bump magnets in RCS. The simulation study was done on the application of the new method to the CSNS/RCS, and the results show the validity and effectiveness of the method.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB224  
About • paper received ※ 19 May 2021       paper accepted ※ 16 July 2021       issue date ※ 10 August 2021  
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THPAB230 Design of Split Permanent Magnet Quadrupoles for Small Aperture Implementation quadrupole, permanent-magnet, electron, simulation 4247
 
  • I.I. Gadjev, G. Andonian, T.J. Campese, M. Ruelas
    RadiaBeam, Santa Monica, California, USA
  • C.C. Hall
    RadiaSoft LLC, Boulder, Colorado, USA
  
  Permanent magnet quadrupoles are ideal for strong focusing in compact footprints. Recent research in the use of permanent magnet based quadrupole magnets has enabled very high-gradient uses approaching 800T/m in final focus systems. However, in order to achieve high quality field profiles with strong fields, small diameter bore magnets must be used necessitating in vacuum operation, or very small beampipes. For small beampipe geometry, we have developed a hybrid-permanent magnet quadrupole, with steel and permanent magnet wedges, that is able to maintain high quality fields but also readily machinable in a separable design. The split design allows for accurate and reproducible reconfiguration on a beam pipe. In this paper, we will discuss the design, engineering, fabrication and first measurements of the split permanent magnet quadrupole.  
poster icon Poster THPAB230 [1.605 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB230  
About • paper received ※ 15 May 2021       paper accepted ※ 08 July 2021       issue date ※ 30 August 2021  
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THPAB236 First Order Analytic Approaches to Modelling the Vertical Excursion Fixed Field Alternating Gradient Accelerator lattice, closed-orbit, optics, simulation 4262
 
  • M.E. Topp-Mugglestone, S.L. Sheehy
    JAI, Oxford, United Kingdom
  • J.-B. Lagrange, S. Machida
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  
  Whilst the Vertical Excursion Fixed Field Alternating Gradient Accelerator (VFFA) remains a promising solution to a number of problems at the frontiers of accelerator physics, the optics of this type of machine are still poorly understood. Current designers are forced to rely on brute-force numerical tracking codes, with optimisation dependent on time-consuming parameter scans. With an aim to both improve understanding of this machine, as well as to develop tools for rapid design and optimisation of VFFA lattices, first steps towards an analytic approach based on a linearised Hamiltonian formalism have been developed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB236  
About • paper received ※ 13 May 2021       paper accepted ※ 14 July 2021       issue date ※ 10 August 2021  
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THPAB286 Quadrupole Focusing Lenses for Heavy Ion Linac DTL, quadrupole, flattop, operation 4359
 
  • V. Skachkov, A.V. Kozlov, G. Kropachev, T. Kulevoy, D.A. Liakin, O.S. Sergeeva, V.S. Skachkov, Yu. Stasevich
    ITEP, Moscow, Russia
  
  Simulation results of pulsed current electromagnet quadrupoles with integral of the magnetic field gradient up to 7 T are presented. Magnets for the DTL and MEBT focusing channels are designing for the heavy-ion linac in Institute for Theoretical and Experimental Physics (ITEP - NRC "Kurchatov Institute"). Appropriate conditions which promise getting the magnetic lens parameters required at restrictions on the overall length <130 mm as well as on the beam aperture >45 mm are defined. It is shown that the channel acceptance to beam emittance ratio desired not less than 3 can be provided by conventional low-carbon steel up to a magnetic aperture of 50 mm in diameter while beyond this size permendur is out of competition. Some aspects of the pulsed power supply system are considered and main parameters of the pulse current generator (PCG) are given.  
poster icon Poster THPAB286 [0.701 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB286  
About • paper received ※ 14 May 2021       paper accepted ※ 30 June 2021       issue date ※ 02 September 2021  
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THPAB328 Tapered Modular Quadrupole Magnet to Reduce Higher-Order Optical Aberrations quadrupole, simulation, operation, optics 4429
 
  • Y.Z. Shao, G.E. Lawler, B. Naranjo, J.B. Rosenzweig
    UCLA, Los Angeles, USA
  
  Funding: US Department of Energy under the contract Nos. DE-SC0017648, DE-SC0009914 and National Science Foundation Grant No. PHY-1549132m
At UCLA’s SAMURAI Laboratory, there will be a need for beam optics to accommodate operation over a range of beam energies. We present a modular quadrupole design that, in addition to satisfying this requirement, incorporates interchangeable tapered end-pieces for mitigation of higher-order aberrations *. The design progresses in an iterative fashion, whereby the tapered shapes, generated algorithmically, are fed into a field solver, and then the aberrations of the resulting particle trajectories are calculated and minimized.
* R. Baartman, Quadrupole shapes, Phys. Rev. ST Accel. Beams 15, 074002 (2012). 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB328  
About • paper received ※ 19 May 2021       paper accepted ※ 27 July 2021       issue date ※ 20 August 2021  
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THPAB343 Test Results of the Prototype SSR1 Cryomodule for PIP-II at Fermilab cavity, cryomodule, SRF, vacuum 4461
 
  • D. Passarelli, J. Bernardini, C. Boffo, B.M. Hanna, S. Kazakov, T.N. Khabiboulline, A. Lunin, J.P. Ozelis, M. Parise, Y.M. Pischalnikov, V. Roger, B. Squires, A.I. Sukhanov, G. Wu, V.P. Yakovlev, S. Zorzetti
    Fermilab, Batavia, Illinois, USA
  • C. Contreras-Martinez
    FRIB, East Lansing, Michigan, USA
  
  Funding: Work supported by Fermi Research Alliance, LLC under Contract No. DEAC02- 07CH11359 with the United States Department of Energy
A prototype cryomodule containing eight Single Spoke Resonators type-1 (SSR1) operating at 325 MHz and four superconducting focusing lenses has been successfully assembled and cold tested in the framework of PIP-II project at Fermilab. The performance of cavities and focusing lenses along with test results of other cryomodule’s key parameters are presented in this contribution. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB343  
About • paper received ※ 20 May 2021       paper accepted ※ 08 August 2021       issue date ※ 28 August 2021  
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THPAB372 SABINA: A Research Infrastructure at LNF laser, radiation, experiment, electron 4505
 
  • L. Sabbatini, D. Alesini, M.P. Anania, M. Bellaveglia, A. Biagioni, B. Buonomo, S. Cantarella, F. Cardelli, E. Chiadroni, G. Costa, G. Di Pirro, F. Dipace, A. Esposito, M. Ferrario, M. Galletti, A. Gallo, A. Ghigo, L. Giannessi, A. Giribono, S. Incremona, L. Pellegrino, L. Piersanti, R. Pompili, R. Ricci, J. Scifo, A. Stecchi, A. Stella, C. Vaccarezza, A. Vannozzi, S. Vescovi, F. Villa
    INFN/LNF, Frascati (Roma), Italy
  • A. Cianchi
    Università di Roma II Tor Vergata, Roma, Italy
  • A. Cianchi
    INFN-Roma II, Roma, Italy
  • A. Doria, A. Petralia
    ENEA C.R. Frascati, Frascati (Roma), Italy
  • L. Giannessi
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • S. Lupi
    Sapienza University of Rome, Roma, Italy
  • S. Macis
    La Sapienza University of Rome, Rome, Italy
  • V. Petrillo
    Universita’ degli Studi di Milano, Milano, Italy
  • V. Petrillo
    INFN-Milano, Milano, Italy
  
  Funding: SABINA is a project co-funded by Regione Lazio within POR-FESR 2014-2020 program.
SABINA (Source of Advanced Beam Imaging for Novel Applications) is a project aimed at the enhancement of the SPARC_LAB research facility. This enhancement is carried out through the following actions: first, the increase of the uptime through the consolidation of technological systems and the replacement of some critical equipment in order to limit the number and extent of faults; then, the improvement of the accelerator performances, by replacing some devices with updated ones. The effect will be greater reliability of the accelerator, which will allow it to be opened as a facility for external users, both industrial and scientific, with the goal of increasing the competitiveness of industries in a broad range of technological areas and enhancing collaborations with research institutions. The two user lines that will be implemented are a power laser target area and a THz radiation line, by using a dedicated undulator. The undulator and the THz line are also described in other contributions to this conference. A brief description of the project and potential exploitations are reported. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB372  
About • paper received ※ 24 May 2021       paper accepted ※ 01 July 2021       issue date ※ 20 August 2021  
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