Keyword: plasma
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MOPAB049 Gyroresonant Acceleration of Electrons by an Axisymmetric Transverse Electric Field electron, resonance, acceleration, cyclotron 213
 
  • E.A. Orozco, O. Otero Olarte
    UIS, Bucaramanga, Colombia
  
  The acceleration of electrons using gyromagnetic autoresonance consist on the sustaint of the electron cyclotron resonant condition through of a magnetic field which increase on time, this scheme was propose by K. S. Golovanivsky. In this work, we considerer the gyroresonant acceleration of electrons using an axisymmetric transverse electric field and its limitations. The 2D acceleration of electrons by a TE011 cylindrical mode is studied numerically. The trajectory, energy and phase-shift between the electron transverse velocity and the electric field are determined by the numerical solution of the relativistic Newton-Lorentz equation using a finite difference scheme. The growth rate of the magnetic field obtained is such that it maintains the phase difference within the acceleration band. The study includes the evolution of the energy for electrons initially ubicated in diferents initial points. For an electron that starts from rest and located at the radial midpoint of the transverse central plane of the cavity, it is reaches an energy close to 560 keV in 625 cycles of the microwave field using an electric field amplitude of 1 kV/cm and a frequency of 2.45 GHz.  
poster icon Poster MOPAB049 [3.541 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB049  
About • paper received ※ 17 May 2021       paper accepted ※ 14 June 2021       issue date ※ 23 August 2021  
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MOPAB054 Start-to-End Simulation of a Free-Electron Laser Driven by a Laser-Plasma Wakefield Accelerator laser, bunching, electron, radiation 233
 
  • W. Liu, Y. Jiao, S. Wang
    IHEP, Beijing, People’s Republic of China
  
  The rapid development of laser-plasma wakefield accelerator (LPA) has opened up a new possible way to achieve ultra-compact free-electron laser (FEL). To this end, LPA experts have made many efforts to generate electron beams with sub-micrometer emittance and low energy spread. Recently, a new laser modulation method was proposed for generating EUV coherent pulse in an LPA-driven FEL. The simulation demonstration of this scheme is based on the Gaussian beam. However, the distribution of the LPA beam is not Gaussian. To further verify the feasibility of the method mentioned above, a start-to-end simulation is required.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB054  
About • paper received ※ 18 May 2021       paper accepted ※ 27 May 2021       issue date ※ 22 August 2021  
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MOPAB145 Acceleration and Focusing of Positron Bunch by Electron Bunch Wakefield in the Dielectric Waveguide Filled with Plasma positron, electron, focusing, 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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MOPAB148 Liénard-Wiechert Numerical Radiation Modeling for Plasma Acceleration Experiments at FACET-II radiation, betatron, acceleration, experiment 517
 
  • M. Yadav, G. Andonian, C.E. Hansel, N. Majernik, P. Manwani, B. Naranjo, J.B. Rosenzweig, O. Williams, Y. Zhuang
    UCLA, Los Angeles, California, USA
  • G. Andonian
    RadiaBeam, Marina del Rey, California, USA
  • O. Apsimon, A. Perera, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • O. Apsimon, A. Perera, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: This work was supported by DE-SC0009914 (UCLA) and the STFC Liverpool Centre for Doctoral Training on Data Intensive Science (LIV. DAT) under grant agreement ST/P006752/1.
Future plasma acceleration experiments at FACET-II will measure betatron radiation in order to provide single-shot non-destructive beam diagnostics. We discuss three models for betatron radiation: a new idealized particle tracking code with Liénard-Wiechert radiation, a Quasi-Static Particle-in-Cell (PIC) code with Liénard-Wiechert radiation, and a full PIC code with radiation computed via a Monte-Carlo QED Method. Predictions of the three models for the E-310 experiment are presented and compared. Finally, we discuss beam parameter reconstruction from the double differential radiation spectrum. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB148  
About • paper received ※ 24 May 2021       paper accepted ※ 01 June 2021       issue date ※ 17 August 2021  
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MOPAB149 Ion Motion in Flat Beam Plasma Accelerators emittance, electron, collider, linear-collider 521
 
  • M. Yadav, C.E. Hansel, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • O. Apsimon, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • O. Apsimon, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: This work was supported by UCLA and the STFC Liverpool Centre for Doctoral Training on Data Intensive Science (LIV. DAT) under grant agreement ST/P006752/1. This work is done on SCARF Cluster.
Intense beams, such as those in proposed plasma based linear colliders, can not only blow out electrons to form a bubble but can also attract ions towards the beam. This violates the assumption that the ions are stationary on the timescale of the beam, which is a common assumption for shorter and less intense beams. While some research has been done on understanding the physics of ion motion in blowout Plasma Wakefield Accelerators (PWFAs), this research has almost exclusively focused on cylindrically symmetric beams, rather than flat asymmetric emittance beams which are often used in linear colliders in order to minimize beamstrahlung at the final focus. This contribution investigates both analytically and computationally ion motion of a flat beam scenario in order to understand the basic physics as well as how to mitigate emittance growth, beam hosing and quadrupole. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB149  
About • paper received ※ 24 May 2021       paper accepted ※ 17 June 2021       issue date ※ 11 August 2021  
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MOPAB156 Wakefields and Transverse Bunch Dynamics Studies of a Plasma-Dielectric Accelerating Structure wakefield, GUI, focusing, 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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MOPAB164 Miniature, High Strength Transport Line Design for Laser Plasma Accelerator-Driven FELs laser, quadrupole, electron, undulator 561
 
  • S. Fatehi, A. Bernhard, A.-S. Müller, M.S. Ning
    KIT, Karlsruhe, Germany
  
  Funding: This work is supported by the BMBF project 05K19VKA PlasmaFEL (Federal Ministry of Education and Research).
Laser-plasma acceleration is an outstanding candidate to drive the next-generation compact light sources and FELs. To compensate large chromatic effects using novel compact beam optic elements in the beam transport line is required. We aim at designing miniature, high strength, normal conducting and superconducting transport line magnets and optics for capturing and matching LPA-generated electron bunches to given applications. Our primary application case is a demonstration experiment for transverse gradient undulator (TGU) FELs, to be performed at the JETI laser facility, Jena, Germany. In this contribution, we present the current design of the beam transport line magnets and the beam optics calculations.
Laser Plasma Accelerators, FELs, Magnets, Beam Dynamics, Superconductivity, transverse gradient undulator 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB164  
About • paper received ※ 19 May 2021       paper accepted ※ 25 May 2021       issue date ※ 20 August 2021  
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MOPAB165 Identical Focusing of Train of Relativistic Positron Gaussian Bunches in Plasma focusing, 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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MOPAB166 Wakefield Excitation by a Sequence of Laser Pulses in Plasma laser, wakefield, simulation, acceleration 568
 
  • 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).
PIC simulation by means of 2.5D UMKA code * of the wakefield excitation by a sequence of three Gaussian laser pulses in plasma was carried out. The dependence of excited wakefield intensity on power and width of laser pulses was investigated. It was shown the coherent addition of wakefield, excited by each laser pulse of the sequence, for linear case, while for the nonlinear case the coherency was destroyed. The profiled sequence of laser pulses was also considered. The possibility to obtain the same total wakefield excited by the profiled sequence of laser pulses with decreasing intensity, as for the uniform sequence was studied.
* G. I. Dudnikova et al. Comp. Techn. 10 (2005) 37. 		 
poster icon Poster MOPAB166 [2.638 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB166  
About • paper received ※ 17 May 2021       paper accepted ※ 20 May 2021       issue date ※ 15 August 2021  
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MOPAB167 Wakefield Excitation in Plasma of Metallic Density by a Laser Pulse laser, wakefield, electron, acceleration 571
 
  • 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 Foundation of Ukraine under the program "Leading and Young Scientists Research Support" (project # 2020.02/0299).
Recently the proposal to use X-ray Exawatt pulse for particle acceleration in a crystal has been declared *. Short X-ray high-power pulse excites wakefield in electron plasma of metallic density which can be used for high gradient acceleration of charged particles. This wakefield is suited for laser wakefield acceleration. In this paper there are simulated with PIC code UMKA: excitation of the large wakefield amplitude up to several TV/m in electron plasma of metallic density by a powerful X-ray laser pulse; laser-plasma wakefield acceleration of self-injected electron bunch in such setup; combined acceleration by plasma wakefield driven by a laser pulse (LPWA) and by self-injected electron bunch (PWFA).
* T.Tajima. Eur. Phys. J. Special Topics 223 (2014) 1037. 		 
poster icon Poster MOPAB167 [2.054 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB167  
About • paper received ※ 17 May 2021       paper accepted ※ 21 May 2021       issue date ※ 22 August 2021  
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MOPAB168 Nanoplasmonic Accelerators Towards Tens of TeraVolts per Meter Gradients Using Nanomaterials electron, wakefield, experiment, focusing 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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MOPAB171 Numerical Simulation on Plasma-Based Beam Dumps Using Smilei laser, electron, wakefield, acceleration 582
 
  • S. Kumar, C. Davut, G.X. Xia
    UMAN, Manchester, United Kingdom
  • A. Bonatto, C. Davut, L. Liang
    The University of Manchester, Manchester, United Kingdom
  • A. Bonatto
    Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil
  • B.S. Nunes
    IF-UFRGS, Porto Alegre, Brazil
  • R.P. Nunes
    UFRGS, Porto Alegre, Brazil
  
  The active plasma beam dump utilizes a laser to generate a plasma wakefield and decelerate an externally injected beam to low energy. We use the particle-in-cell code "Smi-lei" for the investigation of electron beam energy loss in plasma. In this research work, we optimize the laser and plasma parameters to investigate the active plasma beam dump scheme. In doing so, most of the beam energy will be deposited in the plasma. The optimization strategy for the beam energy loss in plasma is presented.
*A. Bonatto, C. B. Schroeder et al., Physics of Plasmas 22 (8) 083106 (2015).
*G. Xia, A. Bonatto et al., Instruments 4 (2) 10 (2020).
*A Bonatto et al., J. Phys.: Conf. Ser. 1596 012058, 2020.
 		 
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB171  
About • paper received ※ 15 May 2021       paper accepted ※ 24 May 2021       issue date ※ 26 August 2021  
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MOPAB173 Physics Program and Experimental for AWAKE Run 2 electron, wakefield, proton, experiment 586
 
  • P. Muggli
    MPI, Muenchen, Germany
  
  Run 1 experimental results demonstrate many characteristics of the self-modulation (SM) in plasma of a long, 400GeV SPS proton bunch*. Externally injected, 19MeV electrons were accelerated to 2GeV**. Based on these results, we are assembling a physics and experiment program aiming at producing a multi-GeV electron bunch with emittance and energy spread sufficiently low for possible early applications to high-energy physics experiments. Plans include two plasmas, the first for SM, the second for acceleration, and of scalable length, separated by an injection region. The first plasma includes a density step to maintain large-amplitude wakefields after saturation of the SM process. Seeding of the SM process may be obtained from an electron bunch. The 150MeV witness electron bunch from an S-band gun, X-band linac has parameters that produce plasma electron blow out and loading of the wakefields in order to minimize final energy spread and emittance***. We are studying the possibility of using a helicon plasma source for the accelerator, a source that can in principle be very long (100s of m).
*AWAKE, PRL 122, 054802 (2019), Turner, PRL 122, 054801 (2019), Turner, PRAB 23, 081302, (2020), Braunmueller PRL 125, 264801 (2020)
**AWAKE, Nature 561, 363 (2018)
***Olsen, PRAB 21, 011301 (2018) 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB173  
About • paper received ※ 18 May 2021       paper accepted ※ 28 May 2021       issue date ※ 02 September 2021  
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MOPAB209 Commissioning of SANAEM RFQ Accelerator rfq, cavity, vacuum, proton 690
 
  • B. Yasatekin, A. Alacakir, A.S. Bolukdemir, I. Kilic, Y. Olgac
    TENMAK-NUKEN, Ankara, Turkey
  • E. Cicek
    KEK, Ibaraki, Japan
  • E. Cosgun
    UNIST, Ulsan, Republic of Korea
  
  The former SANAEM RFQ is upgraded with a newly manufactured cavity, made of oxygen-free copper (OFC), having the capability of accelerating protons from 20 keV to 1.3 MeV. In the assembling of cavity vanes, flanges, etc., indium wire is preferred over the brazing process providing a more flexible and easy method for vacuum sealing. After assembling the cavity, argon plasma cleaning is performed for the final cleaning and RF pre-conditioning. Vacuum tests revealed that levels of 2·10-7 mbar could be achieved quite easily. RF power conditioning of the RFQ cavity is successfully completed with the observation of quite few sparks. In the commissioning tests with the proton beam, a magnetic analyzer is used to measure the energy of the particles. This paper presents the strategy and the results concerning the commissioning of the proton beam with special emphasis on the RFQ cavity.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB209  
About • paper received ※ 19 May 2021       paper accepted ※ 14 June 2021       issue date ※ 22 August 2021  
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MOPAB241 Design of the Proton and Electron Transfer Lines for AWAKE Run 2c electron, proton, acceleration, experiment 778
 
  • R.L. Ramjiawan
    JAI, Oxford, United Kingdom
  • S. Döbert, E. Gschwendtner, P. Muggli, F.M. Velotti, L. Verra
    CERN, Meyrin, Switzerland
  • J.P. Farmer
    MPI-P, München, Germany
  • P. Muggli
    MPI, Muenchen, Germany
  
  The AWAKE Run 1 experiment achieved electron acceleration to 2 GeV using plasma wakefield acceleration driven by 400 GeV, self-modulated proton bunches from the CERN SPS. The Run 2c phase of the experiment aims to build on these results by demonstrating acceleration to ~10 GeV while preserving the quality of the accelerated electron beam. To realize this, there will be an additional plasma cell, to separate the proton bunch self-modulation and the electron acceleration. A new 150 MeV beamline is required to transport and focus the witness electron beam to a beam size of several microns at the injection point. This specification is designed to preserve the beam emittance during acceleration, also requiring micron-level stability between the driver and witness beams. To facilitate these changes, the Run 1 proton transfer line will be reconfigured to shift the first plasma cell 40 m downstream. The Run 1 electron beamline will be adapted and used to inject electron bunches into the first plasma cell to seed the proton bunch self-modulation. Proposed adjustments to the proton transfer line and studies for the designs of the two electron transfer lines are detailed in this contribution.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB241  
About • paper received ※ 18 May 2021       paper accepted ※ 02 June 2021       issue date ※ 17 August 2021  
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MOPAB318 Beam Characterization of Five Electrode ECR Ion Source emittance, ECR, ECRIS, experiment 980
 
  • H.M. Kewlani, S. Gharat, S. Krishnagopal, J.V. Mathew, S.V.L.S. Rao
    BARC, Mumbai, India
  • B. Dikshit, H.M. Kewlani, S. Krishnagopal
    Homi Bhbha National Institute (HBNI), DAE, Mumbai, India
  
  A five electrode ECR Ion Source (ECRIS) was developed for the Low Energy High-Intensity Proton Accelerator (LEHIPA) at BARC. The ECRIS is operated at the energy of 50 keV with a beam current of 20 mA. The ECRIS characterization is done for the beam current, beam emittance, and proton fraction in continuous and pulse beam operation. The pulsed beam operation of the ion source starting from 500 µs to 200 ms of pulse on time with a repetition rate of 1 to 10 Hz. The transverse beam emittance measurement is done by using an Allison scanner. The beam emittance characterization experiments are conducted by varying applied microwave power to the plasma, operating gas pressure of plasma and puller voltage. The measured beam emittance is in the range of 0.3 pi.mm. mrad to 0.4 pi.mm. mrad for 50 keV beam. In this paper beam emittance experiment setup and results are discussed.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB318  
About • paper received ※ 19 May 2021       paper accepted ※ 10 June 2021       issue date ※ 16 August 2021  
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MOPAB360 Anomalous Skin Effect Study of Normal Conducting Film impedance, ECR, interface, vacuum 1119
 
  • B.P. Xiao, M. Blaskiewicz, T. Xin
    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.
For the radiofrequency (RF) applications of normal conducting film with large mean free path at high frequency and low temperature, the anomalous skin effect differs considerably from the normal skin effect with field decaying exponentially in the film. Starting from the relationship between the current and the electric field (E field) in the film, the amplitude of E field along the film depth is calculated, and is found to be non-monotonic. The surface impedance is found to have a minimum value at certain film thickness. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB360  
About • paper received ※ 17 May 2021       paper accepted ※ 25 June 2021       issue date ※ 17 August 2021  
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TUPAB026 Application of Plasma Lenses as Optical Matching Device for Positron Sources at Linear Colliders positron, simulation, target, optical-matching 1394
 
  • M. Formela, N. Hamann, G.A. Moortgat-Pick
    University of Hamburg, Hamburg, Germany
  • K. Flöttmann, G.A. Moortgat-Pick
    DESY, Hamburg, Germany
  • S. Riemann
    DESY Zeuthen, Zeuthen, Germany
  
  Funding: Quantum Universe
In the baseline design of the International Linear Collider (ILC) an undulator-based positron source is foreseen. The proposed luminosity of the recently chosen first energy stage with √{s}=250 GeV requires an improvement by a factor of 2500 to the world’s first linear collider, the past SLC experiment. This ambitious luminosity goal can only be achieved, if all technological boundaries are being pushed. One such area is the captured positron number, which is primarily determined in the capture section within the positron source and specifically by its optical matching device. It is responsible for transforming the phase-space of the outgoing particles produced in the target for the succeeding accelerator sections. The plasma lens is a new candidate for this task. It being an especially adequate method due its magnetic field being azimuthal. Optimizing an idealised tapered active plasma lens for the ILC led us to a design with improved captured positron yield, outperforming ILC’s currently proposed quarter wave transformer by approximately 50%. The captured yield also proved to be stable within ±1.5% for deviations in design parameters of ±10%. 		 
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB026  
About • paper received ※ 20 May 2021       paper accepted ※ 24 June 2021       issue date ※ 24 August 2021  
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TUPAB057 Carbon Beam at I-3 Injector for Semiconductor Implantation radiation, laser, target, ion-source 1489
 
  • A.A. Losev, P.N. Alekseev, N.N. Alexeev, T. Kulevoy, A.D. Milyachenko, Yu.A. Satov, A. Shumshurov
    ITEP, Moscow, Russia
  • P.B. Lagov
    NUST MISIS, Moscow, Russia
  • M.E. Letovaltseva
    MIREA, Moscow, Russia
  • Y.S. Pavlov
    IPCE RAS, Moscow, Russia
  
  Carbon implantation can be effectively used for axial minority charge carriers lifetime control in various silicon bulk and epitaxial planar structures. When carbon is implanted, more stable recombination centers are formed and silicon is not doped with additional impurities, as for example, when irradiated with protons or helium ions. Economically, such a process competes with alternative methods, and is more efficient for obtaining small lifetimes (several nanoseconds). I-3 ion injector with laser-plasma ion source in Institute for theoretical and experimental physics (ITEP) is used as ion implanter in semiconductors. The ion source uses pulsed CO2 laser setup with radiation-flux density of 1011 W/cm2 at target surface. The ion source produces beams of various ions from solid targets. The generated ion beam is accelerated in the two gap RF resonator at voltage of up to 2 MV per gap. Resulting beam energy is up to 4 MV per charge. Parameters of carbon ion beam generated and used for semiconductor samples irradiation during experiments for axial minority charge carriers lifetime control in various silicon bulk and epitaxial planar structures are presented.  
poster icon Poster TUPAB057 [0.630 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB057  
About • paper received ※ 15 May 2021       paper accepted ※ 28 May 2021       issue date ※ 01 September 2021  
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TUPAB095 Arbitrary Longitudinal Pulse Shaping with a Multi-Leaf Collimator and Emittance Exchange wakefield, acceleration, laser, emittance 1600
 
  • N. Majernik, G. Andonian, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • D.S. Doran, G. Ha, J.G. Power, E.E. Wisniewski
    ANL, Lemont, Illinois, USA
  • R.J. Roussel
    Enrico Fermi Institute, University of Chicago, Chicago, Illinois, USA
  
  Funding: DOE HEP Grant DE-SC0017648, and National Science Foundation Grant No. PHY-1549132
Drive and witness beams with variable current profiles and bunch spacing can be generated using an emittance exchange beamline (EEX) in conjunction with transverse masks. Recently, this approach was used to create advanced driver profiles and demonstrate record-breaking plasma wakefield transformer ratios [Roussel, R., et al., Phys. Rev. Lett. 124, 044802 (2020)], a crucial advancement for effective witness acceleration. Presently, these transverse masks are individually laser cut, making the refinement of beam profiles a slow process. Instead, we have proposed the used of a UHV compatible multileaf collimator (MLC) to replace these masks. An MLC permits real-time adjustment of the beam masking, permitting faster optimization in a manner highly synergistic with machine learning. Beam dynamics simulations have shown that practical MLCs offer resolution that is functionally equivalent to that offered by the laser cut masks. In this work, the engineering considerations and practical implementation of such a system at the AWA facility are discussed and the results of benchtop tests are presented.
* Roussel, Ryan, et al. PRL 124.4 (2020): 044802 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB095  
About • paper received ※ 19 May 2021       paper accepted ※ 20 July 2021       issue date ※ 29 August 2021  
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TUPAB136 On Nonlinear Electron Beam Dynamics in a Plasma Environment electron, emittance, linear-dynamics, wakefield 1707
 
  • H.Y. Barminova
    MEPhI, Moscow, Russia
  • B. Kak
    RUDN University, Moscow, Russia
  
  The nonlinear dynamics of an electron beam propagating in a low-density plasma is investigated. The beam envelope equation is obtained analytically for the case of an axisymmetric beam using a model approximation close to the Kapchinsky-Vladimirsky model. Solutions of the envelope equation are presented for various initial conditions (beam current, initial beam radius, transverse beam emittance).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB136  
About • paper received ※ 19 May 2021       paper accepted ※ 26 May 2021       issue date ※ 26 August 2021  
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TUPAB138 Determination of the Phase of Wakefield Driven by a Self-Modulated Proton Bunch in Plasma wakefield, electron, proton, emittance 1710
 
  • K. Moon, M. Chung
    UNIST, Ulsan, Republic of Korea
  • P. Muggli
    MPI-P, München, Germany
  
  Funding: This work was partly supported by the National Research Foundation of Korea (Nos. NRF-2016R1A5A1013277 and NRF-2020R1A2C1010835)
The phase of wakefield driven by a self-modulated proton bunch depends on the type of seeding method and by the beam-plasma parameters.* Particularly when a preceding electron bunch generates seed wakefield, the proton bunch modulation is strongly affected by the seed bunch dynamics along with the plasma. Intrinsic wakefield dephasing from self-modulation of proton bunch can lead to complex evolution of the bunch and wakefield, making it difficult to design an experimental setup for witness beam injection. Using the particle-in-cell code FBPIC,** we investigate in detail the trends of seed electron and driver proton bunch parameter sensitivity to the phase of wakefield in time in the proton bunch frame. We focus on the parameters affecting the phase of the wakefield through the beam’s radial dynamics, such as beam emittance, radial size, energy, and beam to plasma density ratio. Parameter variations are compared to those in the case of the phase of wakefield driven by a non-evolving seed bunch.
*F. Batsch, arXiv:2012.09676 [physics.plasm-ph]
**R. Lehe, M. Kirchen, I.A. Andriyash, B.B. Godfrey, and J.-L. Vay, Comput. Phys. Comm. 203, 66-82 (2016) 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB138  
About • paper received ※ 19 May 2021       paper accepted ※ 21 June 2021       issue date ※ 30 August 2021  
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TUPAB141 On the Development of a Low Peak-Power, High Repetition-Rate Laser Plasma Accelerator at IPEN laser, electron, experiment, photon 1713
 
  • A. Bonatto
    Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil
  • E.P. Maldonado
    ITA, São José dos Campos, Brazil
  • R.P. Nunes
    UFRGS, Porto Alegre, Brazil
  • R.E. Samad, F.B.D. Tabacow, N.D. Vieira, A.V.F. Zuffi
    IPEN-CNEN/SP, São Paulo, Brazil
  
  Funding: FAPESP (Grant #2018/25961), CNPq and CAPES.
In this work, the current status on the development of a laser plasma accelerator at the Nuclear and Energy Research Institute (Instituto de Pesquisas Nucleares e Energéticas, IPEN/CNEN), in São Paulo, Brazil, is presented. Short pulses to be produced by an under-development near-TW, kHz laser system will be used to ionize a gas jet, with a density profile designed to optimize the self-injection of plasma electrons. The same laser pulse will also drive a plasma wakefield, which will allow for electron acceleration in the self-modulated regime. The current milestone is to develop the experimental setup, including electron beam and plasma diagnostics, required to produce electron bunches with energies of a few MeV. Once this has been achieved, the next milestone is to produce beams with energies higher than 50 MeV. Besides kickstarting the laser wakefield accelerator (LWFA) technology in Brazil, this project aims to pave the way for conducting research on the production of radioisotopes by photonuclear reactions, triggered by LWFA-accelerated beams. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB141  
About • paper received ※ 18 May 2021       paper accepted ※ 15 June 2021       issue date ※ 10 August 2021  
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TUPAB142 Simulation Study of Laser Wakefield Acceleration Varying the Down-Ramp Length of a Gas Jet electron, laser, simulation, injection 1717
 
  • R.P. Nunes
    UFRGS, Porto Alegre, Brazil
  • A. Bonatto
    Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil
  • E.P. Maldonado
    ITA, São José dos Campos, Brazil
  • R.E. Samad, N.D. Vieira
    IPEN-CNEN/SP, São Paulo, Brazil
  
  In this work, particle-in-cell simulations were carried out to investigate the role of the down-ramp length of a H\textsubscript{2} gas jet in accelerating electrons ionized by the laser pulse. The laser and plasma density were chosen so that the system is operating in the self-modulated regime. Preliminary results show how the down-ramp length can control the injection of electrons in the first bubble induced in the plasma by the laser pulse.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB142  
About • paper received ※ 20 May 2021       paper accepted ※ 15 June 2021       issue date ※ 13 August 2021  
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TUPAB143 Laser Pulse Dynamics in the Self-Modulated Regime laser, electron, wakefield, simulation 1721
 
  • R.P. Nunes
    UFRGS, Porto Alegre, Brazil
  • A. Bonatto
    Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil
  • E.P. Maldonado
    ITA, São José dos Campos, Brazil
  • R.E. Samad, N.D. Vieira
    IPEN-CNEN/SP, São Paulo, Brazil
  
  In this work, particle-in-cell simulations were carried out to investigate the dynamics of a laser pulse propagating along a H2 gas jet. The laser-driven wakefield and the density of ionized electrons are analyzed during the pulse propagation through the gas jet. The laser and plasma quantities were chosen in order to have the system operating in the self-modulated regime. Results show how the self-modulation fragments the laser pulse, originating higher-amplitude pulses that can induce bubble formation with wave-breaking and particle injection.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB143  
About • paper received ※ 19 May 2021       paper accepted ※ 14 June 2021       issue date ※ 21 August 2021  
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TUPAB145 Methods for Numerical Noise Mitigation in Quasistatic Three-Dimensional Particle-in-Cell Code LCODE3D simulation, wakefield, acceleration, electron 1725
 
  • I.Yu. Kargapolov, K.V. Lotov, A. Sosedkin
    Budker INP & NSU, Novosibirsk, Russia
  • I.A. Shalimova
    ICM&MG SB RAS, Novosibirsk, Russia
  • I.A. Shalimova, P.V. Tuev
    NSU, Novosibirsk, Russia
  • P.V. Tuev
    BINP SB RAS, Novosibirsk, Russia
  
  We discuss a new quasistatic 3D particle-in-cell code LCODE3D for simulating plasma wakefield acceleration, which is a modified version of the quasistatic 2D3V code LCODE, focus on the numerical noise of the plasma solver and propose methods for reducing it. We compare different particle shape functions, as these functions affect the code stability. We also introduce the so-called dual plasma approach, which improves stability and dampens small-scale noise. After applying the proposed methods, the results of the new code closely agree with LCODE simulation results.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB145  
About • paper received ※ 19 May 2021       paper accepted ※ 17 June 2021       issue date ※ 25 August 2021  
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TUPAB146 High Brightness Electron Beams from Dragon Tail Injection and the E-312 Experiment at FACET-II laser, injection, electron, experiment 1728
 
  • P. Manwani, N. Majernik, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • D.L. Bruhwiler
    RadiaSoft LLC, Boulder, Colorado, USA
  • B. Hidding
    USTRAT/SUPA, Glasgow, United Kingdom
  • M.D. Litos
    Colorado University at Boulder, Boulder, Colorado, USA
  
  Funding: This work was performed with support of the US Department of Energy under Contract No. DE-SC0009914
The advent of optically triggered injection in multi component plasma wakefield accelerators has been shown to enable a substantial increase in witness electron beam quality. Here we present a novel way of using the overlap of laser and beam radial fields to locally liberate electrons from the tunneling ionization of the non-ionized gas species. These liberated ultracold electrons gain sufficient energy to be trapped in the accelerating phase at the back of the plasma blowout. This method of controlled injection has advantages in precision timing since injection is locked to peak beam current and has the potential of generating beams with very low emittance and energy spread. This method has been investigated using particle-in-cell (PIC) simulations. This scenario corresponds to a planned experiment, E-312, at SLAC’s FACET-II facility. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB146  
About • paper received ※ 20 May 2021       paper accepted ※ 01 July 2021       issue date ※ 22 August 2021  
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TUPAB147 Asymmetric Beam Driven Plasma Wakefields at the AWA wakefield, simulation, emittance, electron 1732
 
  • P. Manwani, H.S. Ancelin, G. Andonian, J.B. Rosenzweig, M. Yadav
    UCLA, Los Angeles, California, USA
  • G. Andonian
    RadiaBeam, Santa Monica, California, USA
  • G. Ha, J.G. Power
    ANL, Lemont, Illinois, 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, Division of High Energy Physics under Contract No. DE-SC0017648 and DE-SC0009914
In future plasma wakefield acceleration-based scenarios for linear colliders, beams with highly asymmetric emittance are expected. In this case, the blowout region is no longer axisymmetric, but elliptical in cross-section, which implies that the focusing is not equal in the two transverse planes. In this paper, we analyze simulations for studying the asymmetries in flat-beam driven plasma acceleration using the round-to-flat-beam transformer at the Argonne Wakefield Accelerator. Beams with high charge and emittance ratios, in excess of 100:1, are routinely available at the AWA. We use particle-in-cell codes to compare various scenarios including a weak blowout, where the plasma focusing effect exhibits higher order mode asymmetry. Further, practical considerations for tunable plasma density using capillary discharge and laser ionization are compared for implementation into experimental designs. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB147  
About • paper received ※ 20 May 2021       paper accepted ※ 13 July 2021       issue date ※ 02 September 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 electron, wakefield, experiment, focusing 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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TUPAB153 Modeling of Capillary Discharge Plasmas for Wakefield Accelerators and Beam Transport simulation, laser, electron, GUI 1740
 
  • N.M. Cook, J.A. Carlsson, S.J. Coleman, A. Diaw, J.P. Edelen
    RadiaSoft LLC, Boulder, Colorado, USA
  • E.C. Hansen, P. Tzeferacos
    Flash Center for Computational Science, Chicago, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC0018719.
Next generation accelerators demand sophisticated beam sources to reach ultra-low emittances at large accelerating gradients, along with improved optics to transport these beams without degradation. Capillary discharge plasmas can address each of these challenges. As sources, capillaries have been shown to increase the energy and quality of wakefield accelerators, and as active plasma lenses they provide orders-of-magnitude increases in peak magnetic field. Capillaries are sensitive to energy deposition, heat transfer, ionization dynamics, and magnetic field penetration; therefore, capillary design requires careful modeling. We present simulations of capillary discharge plasmas using FLASH, a publicly-available multi-physics code developed at the University of Chicago. We report on the implementation of 2D and 3D models of capillary plasma density and temperature evolution with realistic boundary and discharge conditions. We then demonstrate laser energy deposition to model channel formation for guiding intense laser pulses. Lastly, we examine active capillary plasmas with varying fill species and compare our simulations against experimental studies. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB153  
About • paper received ※ 24 May 2021       paper accepted ※ 29 July 2021       issue date ※ 30 August 2021  
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TUPAB155 Obtaining Accelerated Electron Bunch of High Quality in Plasma Wakefield Accelerator wakefield, electron, acceleration, accelerating-gradient 1744
 
  • R.T. Ovsiannikov
    KhNU, Kharkov, Ukraine
  • I.P. Levchuk (Yarovaya), V.I. Maslov, I.N. Onishchenko
    NSC/KIPT, Kharkov, Ukraine
  
  Funding: "This work is supported by National Research Fundation of Ukraine "Leading and Young Scientists Research Support", grant agreement # 2020.02/0299."
Earlier, high-gradient accelerating electrons of a relativistic beam was demonstrated. However, due to dynamic processes in the plasma, there are problems in maintaining the small size and small energy spread of the accelerated electron bunch while maintaining sufficient values of the accelerating wakefields. Also, the question arises about the values of the limiting bunch dimensions at which the accelerating process is stable. To form a stable accelerated electron bunch, a method is usually used that involves the formation of the same accelerating fields at the location of the bunch. The same fields (plateau due to beam loading (see *, **)) in the region of the accelerated bunch allow all its parts to move as a whole, and ensure the preservation of the spatial distribution of electrons over time, which, in fact, means an accelerated beam of good quality. In this report, the problem of electron bunch accelerating by a short or long electron driver-bunch is considered.
* Romeo S., Ferrario M., Rossi A.R. Phys. Rev. Accel. Beams. 23 (2020) 071301.
** Maslov V.I. et al. Problems of Atomic Science and Technology. 6 (2020) 47.
 
poster icon Poster TUPAB155 [1.723 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB155  
About • paper received ※ 18 May 2021       paper accepted ※ 16 June 2021       issue date ※ 23 August 2021  
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TUPAB156 Optimal Field Shape, Accelerating Positron Bunch in Plasma Wakefield wakefield, electron, positron, acceleration 1747
 
  • R.T. Ovsiannikov
    KhNU, Kharkov, Ukraine
  • I.P. Levchuk (Yarovaya), V.I. Maslov, I.N. Onishchenko
    NSC/KIPT, Kharkov, Ukraine
  
  Funding: This work is supported by National Research Fundation of Ukraine "Leading and Young Scientists Research Support", grant agreement # 2020.02/0299.
The quality of the electron or positron beam, accelerated in plasma accelerators, is still insufficient for applications. Accurate control over the properties of the electron or positron beam is a key issue for wakefield plasma accelerators. The effect of the presence of a witness-beam (the effect of the spatial charge distribution of the witness beam) (see [*, **]) to compensate the energy spread of the positron beam in plasma wakefield accelerators has been studied. This paper presents the results of a numerical simulation on the optimization of the parameters of the driver-bunch and witness-bunch for the formation of a self-consistent longitudinal distribution of the accelerating plateau-type field, which leads to the same values of the wakefield for the whole bunch of accelerated particles and minimizing bunch degradation during acceleration by means of an ion-driver-bunch with external injection into the plasma wake accelerator. The dependence of the longitudinal distribution of the accelerating wakefield on the density and shape of the accelerated bunch in the blowout regime was investigated. Plateau formation and energy spread compensation were observed.
* Romeo S., Ferrario M., Rossi A.R. Phys. Rev. Accel. Beams. 23 (2020) 071301.
** Katsouleas T. et al. Particle Accelerators. 22 (1987) 81. 		 
poster icon Poster TUPAB156 [1.200 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB156  
About • paper received ※ 18 May 2021       paper accepted ※ 16 June 2021       issue date ※ 25 August 2021  
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TUPAB157 Obtaining Long Accelerated Electron Bunch of Good Quality in Plasma Wakefield Accelerator at High Transformer Ratio wakefield, electron, acceleration, simulation 1750
 
  • R.T. Ovsiannikov
    KhNU, Kharkov, Ukraine
  • I.P. Levchuk (Yarovaya), V.I. Maslov, I.N. Onishchenko
    NSC/KIPT, Kharkov, Ukraine
  
  Funding: "This work is supported by National Research Fundation of Ukraine "Leading and Young Scientists Research Support", grant agreement # 2020.02/0299."
The efficiency of electron acceleration by a wakefield, excited in a plasma by an electron bunch, is determined by the transformer ratio (see *, **). The transformer ratio is the ratio of energy acquired by the witness to energy lost by the driver. The transformer ratio can be increased by shaping driver-bunch. In this work, using a non-linear version of the 2d3v code lcode (see ***), numerical simulation of excitation of a wakefield in a plasma in blowout regime by a shaped relativistic electron bunch was performed. There is also the problem of maintaining the small dimension and small energy spread of the accelerated electron bunch while maintaining sufficient values of the accelerating gradient and the transformer ratio. Also, the question arises about the values of the limiting dimension of the witness-bunch at which the acceleration process is stable. Numerical simulation solves the problem of electron bunch acceleration of the best quality with simultaneous maximization of the transformer ratio and maximization of the witness bunch length, at which the accelerating gradient and the focusing force are constant.
*Maslov V.I. et al. Problems of Atomic Science and Technology. 4 (2012) 128.
**Baturin S.S., Zholents A. Phys. Rev. ST Accel. Beams. 20 (2017) 061302.
***Lotov K.V. Phys. Plasmas. 5 (1998) 785.
 
poster icon Poster TUPAB157 [1.920 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB157  
About • paper received ※ 18 May 2021       paper accepted ※ 23 June 2021       issue date ※ 30 August 2021  
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TUPAB158 Electron Witness Constraints for AWAKE emittance, acceleration, wakefield, electron 1753
 
  • J.P. Farmer, P. Muggli
    MPI-P, München, Germany
  • E. Gschwendtner
    CERN, Meyrin, Switzerland
  • L. Liang
    The University of Manchester, Manchester, United Kingdom
  • M.S. Weidl
    MPI/IPP, Garching, Germany
  
  The AWAKE project at CERN successfully demonstrated the use of a proton driver to accelerate an electron witness in plasma*. One of the key goals for AWAKE Run2 is to better control this acceleration, separating the proton-beam-modulation and electron-acceleration stages in order to achieve high energy electrons with high beam quality. Controlled acceleration additionally requires careful tuning of the witness bunch parameters at the injection point. In this work, we use particle-in-cell simulations to study the tolerances for this matching, and discuss techniques to loosen these constraints.
*Adli et al. (AWAKE Collaboration), Nature (2018) 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB158  
About • paper received ※ 19 May 2021       paper accepted ※ 14 June 2021       issue date ※ 11 August 2021  
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TUPAB159 Awake Run 2 at CERN electron, experiment, proton, acceleration 1757
 
  • E. Gschwendtner
    CERN, Meyrin, Switzerland
  
  The AWAKE Run 2 experiment, starting in 2021 at CERN, aims to achieve high-charge bunches of electrons accelerated to high energy (~10 GeV) while maintaining beam quality. AWAKE Run 2 also aims to show that the process is scalable so that, by the end of the run, the AWAKE-scheme technology could be used for first particle physics applications. The first two phases of Run 2 include the investigation of the seeding of the proton bunch self-modulation with the current electron beam in the existing AWAKE facility and the test of a second new plasma source with a density step allowing to maintain strong accelerating fields. In the third phase of Run 2, electrons with an energy of 150 MeV, produced in a newly installed electron source, will be injected into a second plasma source and accelerated to high energies (several GeVs) while keeping good emittance. In the fourth phase, it is planned to replace the second plasma source with a scalable one, which eventually could be used for long-distance acceleration and first applications. In this paper, we present the program of the four phases of AWAKE Run 2, the technical challenges and the proposed schedule.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB159  
About • paper received ※ 17 May 2021       paper accepted ※ 11 June 2021       issue date ※ 19 August 2021  
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TUPAB160 Preparation for Electron-Seeding of Proton Bunch Self-Modulation in AWAKE electron, proton, experiment, simulation 1761
 
  • G. Zevi Della Porta, E. Gschwendtner, L. Verra
    CERN, Meyrin, Switzerland
  • K. Moon
    UNIST, Ulsan, Republic of Korea
  • P. Muggli, L. Verra
    MPI, Muenchen, Germany
  
  The next milestone of the Advanced Wakefield Experiment (AWAKE) at CERN will be to demonstrate that the self-modulation of a long proton bunch can be seeded by a short electron bunch preceding it. This seeding method will lead to phase-reproducible self-modulation of the entire proton bunch, as required for the future AWAKE program. In the Spring of 2021, before receiving proton beams from the CERN SPS, AWAKE plans to hold a dry run of the electron seeding experiments, to commission the system and to determine the parameter scans that will be used in experiments with protons. Electron bunches of 10-20 MeV with varying charge, radius, emittance and energy will be sent in 10 m of low-density plasma. The effects of beam-plasma interactions on the amplitude of the wakefields driven by the different bunches will be studied by observing the energy spectra at the end of the plasma. This paper presents preliminary experimental results from the first two days of measurements as well as the beginning of a simulation-based study of electron propagation in plasma.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB160  
About • paper received ※ 18 May 2021       paper accepted ※ 15 June 2021       issue date ※ 27 August 2021  
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TUPAB163 Developing a 50 MeV LPA-Based Injector at ATHENA for a Compact Storage Ring laser, electron, storage-ring, target 1765
 
  • E. Panofski, J. Dirkwinkel, T. Hülsenbusch, A.R. Maier, J. Osterhoff, G. Palmer, T. Parikh, P.A. Walker, P. Winkler
    DESY, Hamburg, Germany
  • C. Braun, T.F.J. Eichner, L. Hübner, S. Jalas, L. Jeppe, M. Kirchen, P. Messner, M. Schnepp, M. Trunk, C.M. Werle
    University of Hamburg, Hamburg, Germany
  • E. Bründermann, B. Härer, A.-S. Müller, C. Widmann
    KIT, Karlsruhe, Germany
  • M. Kaluza, A. Sävert
    HIJ, Jena, Germany
  
  The laser-driven generation of relativistic electron beams in plasma and their acceleration to high energies with GV/m-gradients has been successfully demonstrated. Now, it is time to focus on the application of laser-plasma accelerated (LPA) beams. The "Accelerator Technology HElmholtz iNfrAstructure" (ATHENA) of the Helmholtz Association fosters innovative particle accelerators and high-power laser technology. As part of the ATHENAe pillar several different applications driven by LPAs are to be developed, such as a compact FEL, medical imaging and the first realization of LPA-beam injection into a storage ring. The latter endeavor is conducted in close collaboration between Deutsche Elektronen-Synchrotron (DESY), Karlsruhe Institute of Technology (KIT) and Helmholtz Institute Jena. In the cSTART project at KIT, a compact storage ring optimized for short bunches and suitable to accept LPA-based electron bunches is in preparation. In this conference contribution we will introduce the 50 MeV LPA-based injector and give an overview about the project goals. The key parameters of the plasma injector will be presented. Finally, the current status of the project will be summarized.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB163  
About • paper received ※ 19 May 2021       paper accepted ※ 31 May 2021       issue date ※ 21 August 2021  
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WEPAB017 General Approach to Physics Limits of Ultimate Colliders collider, luminosity, acceleration, radiation 2624
 
  • V.D. Shiltsev
    Fermilab, Batavia, Illinois, USA
  
  The future of the particle physics is critically dependent on feasibility of future energy frontier colliders. The concept of the feasibility is complex and includes at least three factors: feasibility of energy, feasibility of luminosity, and feasibility of cost and construction time. Here we discuss major beam physics limits of ultimate accelerators, take a look into ultimate energy reach of possible future colliders. We also foresee a looming paradigm change for the HEP research as the thrust for higher energies by necessity will mean lower luminosity.  
poster icon Poster WEPAB017 [1.720 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB017  
About • paper received ※ 19 May 2021       paper accepted ※ 24 June 2021       issue date ※ 17 August 2021  
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WEPAB031 Frequency Dependence of Plasma Cascade Amplification electron, distributed, simulation, hadron 2672
 
  • G. Wang, V. Litvinenko, J. Ma
    BNL, Upton, New York, USA
  • V. Litvinenko
    Stony Brook University, Stony Brook, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
A new type of amplifier, plasma cascade amplifier (PCA) has been proposed for a coherent electron cooling (CeC) system. Previously, the 1D model for PCA assumes that the transverse distribution of the density perturbation in the electrons is uniform and consequently, the plasma frequency does not depend on the wavelength of the perturbation. This assumption is valid if the longitudinal wavelength of the beam frame is much shorter than the transverse width of perturbation. In this work, we explore the PCI gain at a long wavelength by assuming the perturbation in the electron density has a non-uniform transverse profile. Specifically, we solve the 3D Poisson equation for given charge distribution (longitudinal sinusoidal, transversely Gaussian, or Beer-can), average the electric field over the transverse plane, and then apply it to 1D Vlasov equation. Similar to the previous calculation, the Vlasov equation can be reduced to a Hill’s equation but the plasma frequency now depends on the longitudinal wavelength of the density perturbation in the electrons. By numerically solving Hill’s equation, we obtain the gain of a PCA and compare it with the results from 3D SPACE simulations. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB031  
About • paper received ※ 20 May 2021       paper accepted ※ 23 June 2021       issue date ※ 27 August 2021  
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WEPAB055 Development of a Linac for Injection of Ultrashort Electron Bunches Into Laser Plasma Electron Accelerators electron, laser, acceleration, linac 2725
 
  • S. Masuda, N. Kumagai, T. Masuda, Y. Otake
    JASRI, Hyogo, Japan
  • Y. Koshiba, S. Otsuka
    Waseda University, Tokyo, Japan
  • T. Sakai, T. Tanaka
    LEBRA, Funabashi, Japan
  • K. Sakaue
    The University of Tokyo, The School of Engineering, Tokyo, Japan
  
  Funding: This work is supported by JST-Mirai Program Grant Number JPMJMI17A1, Japan.
We are developing a C-band linac that produces ultrashort electron bunches as an injector for laser plasma accelerators. A plasma wave excited by a high intense ultrashort laser pulse has a wavelength of the order of 10 to 100 fs and transverse dimensions of the order of 10 to 100 um. To inject the bunch into a proper phase of the plasma wave, a length and transverse sizes of the bunch must be much smaller than the plasma wave structure. A laser triggered photo cathode electron RF-gun and a 2pi/3 mode traveling wave buncher with 24 cells for ultrashort electron bunch production have been developed based on electron beam tracking simulations that show the bunch length is less than 10 fs with a charge of 100 fC at a focus on the plasma wave. The simulations also show that sufficiently small transverse sizes of the bunch at the focus can be obtained by a Q triplet. A highly accurate timing lower than the plasma wavelength (~10fs) is required for the synchronization between the electron bunch injection and the plasma wave excitation. An RF master oscillator with low SSB phase noise (-150dBc/Hz@10MHz) has been developed for the synchronization. We will report present development status. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB055  
About • paper received ※ 19 May 2021       paper accepted ※ 15 July 2021       issue date ※ 29 August 2021  
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WEPAB072 PAX: A Plasma-Driven Attosecond X-Ray Source electron, experiment, FEL, simulation 2755
 
  • C. Emma, J. Cryan, M.J. Hogan, K. Larsen, J.P. MacArthur, A. Marinelli, G.R. White, X.L. Xu
    SLAC, Menlo Park, California, USA
  • A.C. Fisher, R.M. Hessami, P. Musumeci
    UCLA, Los Angeles, California, USA
  • R. Robles
    Stanford University, Stanford, California, USA
  
  Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515. This work was also partially supported by DOE grant DESC0009914
Plasma accelerators can generate ultra high brightness electron beams which open the door to light sources with smaller physical footprint and properties unachievable with conventional accelerator technology. In this work * we show that electron beams from Plasma WakeField Accelerators (PWFAs) can generate coherent tunable soft X-ray pulses with TW peak power and duration of tens of attoseconds in a meter-length undulator. These X-ray pulses are an order of magnitude more powerful, shorter and can be produced with better stability than state-of-the-art X-ray Free Electron Lasers (XFELs). The X-ray emission in this approach is driven by coherent radiation from a pre-bunched, near Mega Ampere (MA) current electron beam of attosecond duration rather than the SASE FEL process starting from noise. This approach significantly relaxes the restrictive requirements on emittance, energy spread, and pointing stability which has thus far hindered the realization of a high-gain FEL driven by a plasma accelerator. We discuss the approach and progress towards the experimental realization of this concept at the FACET-II accelerator facility.
* C. Emma, X. Xu, A. Fisher, J. P. MacArthur, J. Cryan, M. J. Hogan, P. Musumeci, G. White, A. Marinelli, "Terawatt attosecond X-ray source driven by a plasma accelerator", arXiv:2011.07163 (2020) 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB072  
About • paper received ※ 20 May 2021       paper accepted ※ 24 June 2021       issue date ※ 31 August 2021  
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WEPAB109 Initial Study of GaN Thin Films for Photocathodes Prepared by Magnetron Sputtering on Copper Substrates cathode, electron, gun, experiment 2850
 
  • M. Vogel, X. Jiang, C. Wang
    University Siegen, Siegen, Germany
  • P. Murcek, J. Schaber, R. Xiang
    HZDR, Dresden, Germany
  
  Funding: This research is funded by the Federal Ministry of Education and Research of Germany in the framework of BETH (project number 05K19PSB).
On the path for high brightness electron beams, Gallium Nitride (GaN) is one promising candidate for a photo-cathode material. In this contribution, we report on the continuation of the study to optimize the crystallization quality and crystallography of Mg-doped GaN samples on copper substrates that are synthesized by RF magnetron sputtering. SEM and XRD results show that the pretreatment methods and the sputtering conditions (temperature, sputtering power, and partial pressure of the reactive gas) can both affect the morphology and crystal quality of GaN films. The initial QE measurements of these samples are done in our newly build in-situ QE measurement system and the first results of QE analyses done at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) are presented in a dedicated contribution.
Part of this work was performed at the Micro- and Nanoanalytics Facility (MNaF) of the University of Siegen. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB109  
About • paper received ※ 19 May 2021       paper accepted ※ 09 June 2021       issue date ※ 27 August 2021  
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WEPAB139 Beam Tracking Simulations for Stage 1 of the Laser-Hybrid Accelerator for Radiobiological Applications (LhARA) laser, proton, simulation, target 2939
 
  • H.T. Lau
    Imperial College London, London, United Kingdom
  
  The Laser-hybrid Accelerator for Radiobiological Applications (LhARA) is a unique and flexible facility proposed for radiobiological studies. The first stage of LhARA consists of an intense laser source interacting with a thin foil target producing a large flux of protons with energies up to 15 MeV. Particles will propagate through a combination of plasma (Gabor) lenses and magnetic elements to an achromat arc delivering the beam vertically to an in-vitro end station. An end-to-end simulation from the laser source to the end station is required to verify the conceptual design of the beamline. The laser-plasma interaction is simulated with Smilei (a particle-in-cell code) to produce a two-dimensional (2D) distribution of particles. Whilst it is possible to simulate the laser-plasma interaction in three dimensions (3D), access to the computing resources needed to run highly resolved simulations was not available. A sampling routine will be described which samples the 2D distribution to generate a 3D beam. The Monte Carlo simulation programs BDSIM and GPT were used to track the beam. Results of the simulations will be shown and compared to the results of an idealized Gaussian beam.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB139  
About • paper received ※ 18 May 2021       paper accepted ※ 01 July 2021       issue date ※ 10 August 2021  
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WEPAB140 Second Beam Test and Numerical Investigation of the Imperial College Plasma (Gabor) Lens Prototype focusing, 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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WEPAB141 Preliminary Simulation of CERN’s Linac4 H− Source Beam Formation simulation, electron, extraction, linac 2947
 
  • A. Vnuchenko, J. Lettry
    CERN, Geneva, Switzerland
  • U. Fantz, S. Mochalskyy, D. Wünderlich
    MPI/IPP, Garching, Germany
  • T. Minea, A. Revel
    CNRS LPGP Univ Paris Sud, Orsay, France
  
  Linac4 is the new (H−) linear injector of CERN’s accelerator complex. This contribution describes the modelling activities required to get insight into H− beam formation processes and their impact on beam properties. The simulation region starts from a homogeneous hydrogen plasma, the plasma then expands through the magnetic filter field. H− ions and electrons are electrostatically extracted through the meniscus (line of separation between the plasma and the extracted beam) and eventually accelerated. The physics is simulated via the 3D PIC code ONIX. This code, originally dedicated to ITER’s neutral injector sources, has been modified to match single aperture sources. A new type of boundary condition is described, as well as the field distribution and geometry of the standard IS03 and a dedicated proto-type of CERN’s Linac4 H− source. A plasma electrode prototype designed to provide metallic boundary conditions was produced and tested. This plasma electrode geometry enables Optical Emission Spectroscopy in the region closest to meniscus. A set of plasma parameters was chosen as input characterizing the plasma. Preliminary simulation results of beam formation region are presented.  
poster icon Poster WEPAB141 [0.710 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB141  
About • paper received ※ 18 May 2021       paper accepted ※ 02 June 2021       issue date ※ 31 August 2021  
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WEPAB143 Sub-MeV Ion Generation by Standing Wave Excitation of Ionized Gases electron, acceleration, laser, simulation 2951
 
  • Sz. Turnár, G. Almási, J. Hebling, Cs. Korpa, M.I. Mechler, L. Pálfalvi, Z. Tibai
    University of Pecs, Pécs, Hungary
  
  Funding: Hungarian Scientific Research Fund (OTKA) (125808, 129134) ÚNKP-20-3 New National Excellence Program of the Ministry for Innovation and Technology from the source of the National Research
Many ion acceleration techniques have been suggested and thoroughly studied in the last two decades*. One of the promising techniques is the Coulomb explosion acceleration (CEA)**. Using CEA in clusters could result in symmetric acceleration if there are not any other significant mechanisms. We proposed a THz-driven accelerator scheme that is based on CEA in proton, deuterium and heavy water gas plasmas. Two counter-propagating THz pulses are focused to the ionized region of the gas jet. Following the ripping of the electrons from the gas plasmas by ultrafast standing waves, the Coulomb explosion accelerates the positive ions. According to our calculation, using 2 x 34 mJ THz pulses electrons and protons with 1.1 nC charge are accelerated up to 0.4 MeV and 0.1 MeV, respectively. The total energy of the particles is 0.7 % of the energy of the THz pulses. We examined the effect of the initial bunch charge, bunch size and shape on the final energy spectra and the directional distribution of the particles. Our presented technique is scalable from a few µm to a few thousand µm driving wavelengths and can be used for electron and heavy-ion acceleration.
*J. Badziak, IOP Conf. Series: J Phys: Conf. Series 959, 012001 (2018).
** M. Murakami and K. Mima, Phys. of Plasmas 16, 103108 (2009).
 		 
poster icon Poster WEPAB143 [3.467 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB143  
About • paper received ※ 19 May 2021       paper accepted ※ 07 June 2021       issue date ※ 15 August 2021  
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WEPAB174 Study of the Electron Seeded Proton Self-Modulation Using FBPIC proton, wakefield, electron, simulation 3008
 
  • L. Liang, G.X. Xia
    The University of Manchester, Manchester, United Kingdom
  • A. Bonatto
    Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brazil
  • L. Liang, G.X. Xia
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: This work is supported by the Cockcroft Institute Core Grant and the STFC AWAKE Run 2 grant ST/T001917/1
In order to make a full use of the whole proton bunch to drive large amplitude plasma wakefields and suppress the uncontrolled growth of any possible instabilities at the head of the proton bunch, the AWAKE Run 2 experiment plans to use an electron bunch to seed the formation of the proton bunch self-modulation. Additionally, a density step in the plasma channel will be used to freeze the selfmodulation process to keep the wakefield amplitude. In this work, numerical simulations performed with FBPIC are used to investigate the electron seeded proton self-modulation and the effect of the plasma density step as well. 		 
poster icon Poster WEPAB174 [1.751 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB174  
About • paper received ※ 10 May 2021       paper accepted ※ 28 June 2021       issue date ※ 24 August 2021  
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WEPAB175 Simulation Study of Electron Beam Acceleration with Non-Gaussian Transverse Profiles for AWAKE Run 2 emittance, electron, acceleration, wakefield 3012
 
  • L. Liang, G.X. Xia
    The University of Manchester, Manchester, United Kingdom
  • J.P. Farmer
    MPI-P, München, Germany
  • L. Liang, G.X. Xia
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: The authors would like to acknowledge the support from the Cockcroft Institute Core Grant and the STFC AWAKE Run 2 grant ST/T001917/1
In the physics plan for AWAKE Run 2, two known effects, beam loading the longitudinal wakefield and beam matching to the pure plasma ion channel, will be implemented for the better control of electron acceleration. It is founded in our study of beam matching that the transverse profile of the initial witness beam have a significant impact on its acceleration quality. In this paper, particle-in-cell (PIC) simulations are used to study factors that affect the acceleration quality of electron beams with different transverse profiles. 		 
poster icon Poster WEPAB175 [1.860 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB175  
About • paper received ※ 10 May 2021       paper accepted ※ 25 June 2021       issue date ※ 02 September 2021  
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WEPAB183 Big Data Techniques for Accelerator Optimization laser, experiment, wakefield, radiation 3039
 
  • C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: This project has received funding from STFC under grant reference ST/P006752/1.
Accelerators and the experiments that they enable are some of the largest, most data-intensive, and most complex scientific systems in existence. The interrelations between machine subsystems are complicated and often nonlinear. The system dynamics involve large parameter spaces that evolve over multiple relevant time scales and accelerator systems. Any accelerator-based experiments and applications are almost always difficult to model. LIV. DAT, the Liverpool Centre for Doctoral Training in Data-intensive science, was established in 2017 as a hub for training students in Big Data science. The centre currently has 36 PhD students that are working across nuclear, particle and astrophysics, as well as in accelerator science. This paper presents results from R&D into betatron radiation models and beam parameter reconstruction for plasma acceleration experiments at FACET-II, simulations for MeV energy gain in dielectric structures driven by a CO2 laser, and modelling of seeded self-modulation of long elliptical bunches in plasma. It also gives an overview of the training program offered to the LIV. DAT students. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB183  
About • paper received ※ 16 May 2021       paper accepted ※ 16 June 2021       issue date ※ 23 August 2021  
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WEPAB191 Magnet System for a Proton/helium ECR Ion Source ECR, solenoid, ion-source, electron 3066
 
  • M.S. Dmitriyev, K.G. Artamonov, M.V. Dyakonov, M.I. Zhigailova
    MEPhI, Moscow, Russia
  
  The study of the magnetic system of ECRIS with operating frequency of 2.45 GHz for producing protons and double-charged helium ions has been carried out. The results of the numerical simulation of the ECRIS magnetic system based on permanent magnets have been performed. The possibility of shifting the ring magnets in both injection and extraction regions is considered to adjust maximum and minimum values of the axial distribution of a magnetic field in a plasma chamber. The possibility of shifting the bar magnets of the hexapole is shown to provide the adjustment of the radial magnetic field Brad at the chamber wall. Additional solenoids are introduced to the system for providing the required Binj and Bext adjustment and tuning the axial magnetic field distribution including the minimum on the axis Bmin. Furthermore, the magnetic system allows to switch the operation mode of the ECR source to the microwave mode.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB191  
About • paper received ※ 20 May 2021       paper accepted ※ 08 June 2021       issue date ※ 26 August 2021  
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WEPAB256 Three-Dimensional Space Charge Oscillations in a Hybrid Photoinjector emittance, simulation, electron, cathode 3240
 
  • M. Carillo, M. Behtouei, F. Bosco, L. Faillace, A. Giribono, L. Giuliano, M. Migliorati, A. Mostacci, L. Palumbo
    Sapienza University of Rome, Rome, Italy
  • L. Ficcadenti
    INFN-Roma, Roma, Italy
  • J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • B. Spataro, C. Vaccarezza
    INFN/LNF, Frascati, Italy
  
  Funding: This work supported by DARPA GRIT under contract no. 20204571 and partially by INFN National committee V through the ARYA project.
A new hybrid C-band photo-injector, consisting of a standing wave RF gun connected to a traveling wave structure, operating in a velocity bunching regime, has shown to produce an extremely high brightness beam with very low emittance and a very high peak current through a simultaneous compression of the beam in the longitudinal and transverse dimensions. A beam slice analysis has been performed in order to understand the evolution of the relevant physical parameters of the beam in the longitudinal and transverse phase spaces along the structure. A simple model for the envelope equation has been developed to describe the beam behavior in this particular dynamics regime that we term "triple waist", since all three dimensions reach a minimum condition almost simultaneously. The model analyzes the transverse envelope dynamics at the exit of the hybrid photo-injector, in the downstream drift where the triple waist occurs. The analytical solutions obtained from the envelope equation are compared with the simulations, showing a good agreement. Finally, these results have been analyzed also in terms of plasma oscillation to obtain a further physical interpretation of the beam dynamics. 		 
poster icon Poster WEPAB256 [1.162 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB256  
About • paper received ※ 19 May 2021       paper accepted ※ 21 July 2021       issue date ※ 13 August 2021  
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WEPAB265 Simulations of Cooling Rate for Coherent Electron Cooling with Plasma Cascade Amplifier electron, simulation, kicker, hadron 3261
 
  • J. Ma, V. Litvinenko, G. Wang
    BNL, Upton, 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.
Coherent electron cooling (CeC) is a novel technique for rapidly cooling high-energy, high-intensity hadron beams. A plasma cascade amplifier (PCA) has been proposed for the CeC experiment in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). The cooling rate of CeC experiment with PCA has been predicted in 3D start-to-end CeC simulations using code SPACE. 		 
poster icon Poster WEPAB265 [1.507 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB265  
About • paper received ※ 13 May 2021       paper accepted ※ 10 June 2021       issue date ※ 18 August 2021  
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WEPAB266 Simulation Studies of Plasma Cascade Amplifier electron, simulation, emittance, experiment 3265
 
  • J. Ma, V. Litvinenko, G. Wang
    BNL, Upton, 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.
Plasma cascade amplifier (PCA) is an advanced design of amplifier for the coherent electron cooling (CeC) experiment in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Working principle of PCA is the new plasma cascadeμbunching instability occurring in electron beams propagating along a straight trajectory. PCA is cost-effective as it does not require separating electron and hadron beams. SPACE, a parallel, relativistic 3D electromagnetic Particle-in-Cell (PIC) code, has been used for simulation studies of PCA. 		 
poster icon Poster WEPAB266 [2.317 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB266  
About • paper received ※ 13 May 2021       paper accepted ※ 10 June 2021       issue date ※ 31 August 2021  
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WEPAB273 Cooling and Diffusion Rates in Coherent Electron Cooling Concepts electron, proton, kicker, hadron 3281
 
  • S. Nagaitsev, V.A. Lebedev
    Fermilab, Batavia, Illinois, USA
  • W.F. Bergan, E. Wang
    BNL, Upton, New York, USA
  • G. Stupakov
    SLAC, Menlo Park, California, USA
  
  Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
We present analytic cooling and diffusion rates for a simplified model of coherent electron cooling (CEC), based on a proton energy kick at each turn. This model also allows to estimate analytically the rms value of electron beam density fluctuations in the "kicker" section. Having such analytic expressions should allow for better understanding of the CEC mechanism, and for a quicker analysis and optimization of main system parameters. Our analysis is applicable to any CEC amplification mechanism, as long as the wake (kick) function is available. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB273  
About • paper received ※ 10 May 2021       paper accepted ※ 28 July 2021       issue date ※ 29 August 2021  
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WEPAB328 Rapid Surface Microanalysis Using a Low Temperature Plasma cathode, electron, radiation, target 3440
 
  • V.G. Dudnikov, M.A. Cummings, R.P. Johnson
    Muons, Inc, Illinois, USA
  
  There is a need for rapid, high-resolution (micron or sub-micron) scanning of surfaces of special nuclear materials (SNM) and surrogate materials to locate and identify regions of abnormalities. One technique that is commonly used to analyze the composition of solid surfaces and thin films is secondary-ion mass spectrometry (SIMS). SIMS devices are very complex and expensive. We propose to develop simpler, less expensive surface analysis devices, based on glow-discharge optical emission spectroscopy (GOES) that can provide excellent spatial resolution. Ions from a plasma discharge sputtered atoms from the surface and the discharge electrons effectively excite and ionize the sputtered atoms. GOES uses the light emitted by the excited particles for quantitative analysis. In the GOES device, the ion flux is extracted from the gas-discharge plasma and focused to a micron size on the sample, providing very local sputtering and local elemental analysis. The radiation from the sputtered atoms is passed through an optical fiber to an optical spectrometer and recorded. To register the distribution of elements over the sample, the sample is scanned electro-mechanically.  
poster icon Poster WEPAB328 [0.385 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB328  
About • paper received ※ 19 May 2021       paper accepted ※ 29 July 2021       issue date ※ 02 September 2021  
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WEPAB390 High-Quality, Conformal Bellows Coatings Using Ultra-Fast HiPIMS with Precision Ion Energy Control vacuum, target, operation, experiment 3626
 
  • T.J. Houlahan, I. Haehnlein, W.M. Huber, B.E. Jurczyk, I.A. Shchelkanov, R.A. Stubbers
    Starfire Industries LLC, Champaign, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy under Award Number DE-SC0020481.
In this paper we demonstrate a replacement for traditional ’wet’ chemical deposition processes using a vacuum, ionized physical vapor deposition (iPVD) process that results in a conformal metal film, capable of coating complex, convoluted parts that are common in modern particle accelerators (e.g., bellows, RF cavities). Results are presented for a process utilizing the combined deposition and etching that are achieved using ultra-fast high-power impulse magnetron sputtering (HiPIMS) coupled with precision control of the ion energy using a positive voltage reversal. This process results in a conformal film and has been used to coat both test coupons and full bellows assemblies. The resulting Cu films, which are 5-10 µm in thickness, exhibit excellent adhesion. Further, they have been shown to tolerate temperature extremes ranging from 77 K to a 400 C vacuum bakeout as well as extreme plastic deformation of the substrate without any buckling, cracking, or delamination. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB390  
About • paper received ※ 19 May 2021       paper accepted ※ 02 July 2021       issue date ※ 31 August 2021  
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THPAB062 Long-Wave IR Terawatt Laser Pulse Compression to Sub-Picoseconds laser, simulation, experiment, FEM 3893
 
  • I. Pogorelsky, M. Babzien, M.A. Palmer, M.N. Polyanskiy
    BNL, Upton, New York, USA
  
  Funding: U.S. Department of Energy under contract DE-SC0012704
We report an experiment and simulations on post-compression of 2 ps, 0.15 TW CO2 laser pulses to 480 fs, ~0.25 TW by means of a self-phase modulation accompanied by a negative group dispersion in KCl and BaF2 optical slabs. In addition, down to 130 fs fine pulse structure, but at lower conversion efficiency, has been observed through self-compression in a bulk NaCl crystal. The obtained results surpass by far previous achievements in the ultra-fast long-wave IR laser technology 		 
poster icon Poster THPAB062 [2.675 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB062  
About • paper received ※ 12 May 2021       paper accepted ※ 18 June 2021       issue date ※ 24 August 2021  
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THPAB121 Plasma Muon Beam Cooling for HEP focusing, 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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THPAB140 Modelling Seeded Self Modulation of Long Elliptical Bunches in Plasma wakefield, simulation, proton, emittance 4030
 
  • A. Perera, O. Apsimon, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • O. Apsimon, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • J. Resta-López
    IFIC, Valencia, Spain
  
  Funding: This work was supported by STFC Centre for Doctoral Training in Data-Intensive Science (LIV. DAT) under grant ST/P006752/1 and the STFC Scientific Computing Department’s SCARF cluster.
The stability of particle bunches undergoing seeded self-modulation (SSM) over tens or hundreds of meters is crucial to the generation of GV/m wakefields that can accelerate electron beams as proposed for use in several high energy plasma-based linear colliders. Here, 3D particle-in-cell simulations using QuickPIC are compared to an analytical model of seeded self-modulation (SSM) of elliptical beam envelopes using linear wakefield theory. It is found that there is quantitative agreement between simulations and analytical predictions for the envelope in the early growth of the SSM. A scaling law is derived for the reduction of the maximum overall modulation growth rate with aspect ratio and is found to match well with simulation. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB140  
About • paper received ※ 19 May 2021       paper accepted ※ 22 July 2021       issue date ※ 31 August 2021  
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THPAB269 Compton Spectrometer for FACET-II electron, detector, simulation, wakefield 4332
 
  • B. Naranjo, G. Andonian, A. Fukasawa, W.J. Lynn, N. Majernik, J.B. Rosenzweig, Y. Sakai, O. Williams, M. Yadav, Y. Zhuang
    UCLA, Los Angeles, California, USA
  
  Funding: DARPA GRIT Contract 20204571, DOE HEP Grant DE-SC0009914
We present the design of a Compton spectrometer for use at FACET-II. A sextupole is used for magnetic spectral analysis, giving a broad dynamic range (180 keV through 28 MeV) and the capability to capture an energy-angular double-differential spectrum in a single shot. At low gamma energies, below 1 MeV, Compton spectroscopy becomes increasingly challenging as the scattering cross-section becomes more isotropic. To extend the range of the spectrometer down to around 180 keV, we use a 3D-printed tungsten collimator at the detector plane to preferentially select forward-scattered electrons at the Compton edge. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB269  
About • paper received ※ 20 May 2021       paper accepted ※ 22 July 2021       issue date ※ 19 August 2021  
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THPAB284 Analytical and Numerical Characterization of Cherenkov Diffraction Radiation as a Longitudinal Electron Bunch Profile Monitor for AWAKE Run 2 radiation, electron, proton, wakefield 4355
 
  • C. Davut, G.X. Xia
    UMAN, Manchester, United Kingdom
  • O. Apsimon
    The University of Liverpool, Liverpool, United Kingdom
  • O. Apsimon
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • P. Karataev
    Royal Holloway, University of London, Surrey, United Kingdom
  • P. Karataev
    JAI, Egham, Surrey, United Kingdom
  • T. Lefèvre, S. Mazzoni
    CERN, Geneva, Switzerland
  
  In this paper, CST simulations of the coherent Cherenkov Diffraction Radiation with a range of parameters for different dielectric target materials and geometries are discussed and compared with the theoretical investigation of the Polarization Current Approach to design a prototype of a radiator for the bunch length/profile monitor for AWAKE Run 2. It was found that the result of PCA theory and CST simulation are consistent with each other regarding the shape of the emitted ChDR cone.
* Karlovets, D. V. (2011). JETP, 113(1), 27-45.
** Shevelev, M. V., & Konkov, A. S. (2014). JETP, 118(4), 501-511.
*** Curcio, A., et al.(2020). PRAB, 23(2), 022802.
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB284  
About • paper received ※ 16 May 2021       paper accepted ※ 14 July 2021       issue date ※ 10 August 2021  
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THPAB320 ALD-Based NbTiN Studies for SIS R&D site, cavity, SRF, niobium 4420
 
  • I. González Díaz-Palacio, R.H. Blick, R. Zierold
    University of Hamburg, Hamburg, Germany
  • W. Hillert, M. Wenskat
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  
  Superconductor-Insulator-Superconductor multilayers improve the performance of SRF cavities providing magnetic screening of the bulk cavity and lower surface resistance. In this framework NbTiN mixtures stand as a potential material of interest. Atomic layer deposition (ALD) allows for uniform coating of complex geometries and enables tuning of the stoichiometry and precise thickness control in sub-nm range. In this talk, we report about NbTiN thin films deposited by plasma-enhanced ALD on insulating AlN buffer layer. The deposition process has been optimized by studying the superconducting electrical properties of the films. Post-deposition thermal annealing studies with varying temperatures, annealing times, and gas atmospheres have been performed to further improve the thin film quality and the superconducting properties. Our experimental studies show an increase in Tc by 87.5% after thermal annealing and a maximum Tc of 13.9 K has been achieved for NbTiN of 23 nm thickness. Future steps include lattice characterization, using XRR/XRD/EBSD/PALS, and SRF measurements to obtain Hc1 and the superconducting gap.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB320  
About • paper received ※ 24 May 2021       paper accepted ※ 23 July 2021       issue date ※ 18 August 2021  
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THPAB340 Sub-Nanosecond Switching of HV SiC MOS Transistors for Impact Ionisation Triggering kicker, electron, laser, high-voltage 4454
 
  • V. Senaj, T. Kramer, A.A. del Barrio Montañés
    CERN, Geneva 23, Switzerland
  • M. Sack
    KIT, Karlsruhe, Germany
  
  Pulse generators with multi kV/kA pulses are necessary for the particle accelerator environment for beam transfer magnets. Traditionally these generators are using thyratrons - until recently the only switches capable of switching such pulses within tens of ns. There is a strong demand to replace thyratrons with semiconductor switches to avoid their future obsolescence. Very promising candidates are components from the family of fast ionization dynistors triggered by impact ionization. Their sub-nanosecond switching time and extreme current densities can provide performances superior to that of thyratrons. Recent investigations showed that impact ionization triggering is feasible also in cheap industrial thyristors. The main issue is the generation of triggering pulses with slew rates in the multi kV/ns region and with the required output current for charging the parasitic capacitance of the thyristor. We present an approach of generating > 1 kV/ns pulses by ultra-boosted gate driving of HV SiC MOS transistors. We found that the MOS lifetime under these extreme triggering conditions can still reach more than 108 pulses, enough for kicker generator applications.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB340  
About • paper received ※ 18 May 2021       paper accepted ※ 01 July 2021       issue date ※ 27 August 2021  
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