Keyword: photon
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MOPGW053 Residual Gas Lifetime In High Energy Photon Source (HEPS) scattering, electron, dynamic-aperture, vacuum 210
 
  • S.K. Tian, H.S. Xu
    IHEP, Beijing, People’s Republic of China
 
  High vacuum has always been mandatory in particle accelerators. This is especially true for circular machines, where the beam makes thousands or millions turns, and beam lifetime is heavily affected by the residual gas scattering. At the beginning of storage ring operation the lifetime was very short mostly dominated by residual gas scattering. The residual gas lifetime is comprised of the elastic and inelastic scattering on electrons and elastic and inelastic scattering on nuclei. One usually calculates only the elastic scattering on nuclei (single Coulomb scattering) and inelastic scattering on nuclei (bremsstrahlung) of the residual gas scattering lifetime component. The analytic calculation the residual gas scattering lifetime and simulations of the beam interaction with the residual gas with code will be shown in this presentation  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW053  
About • paper received ※ 15 May 2019       paper accepted ※ 19 May 2019       issue date ※ 21 June 2019  
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MOPMP035 Effect of Emittance Constraints on Monochromatization at the Future  Circular e+e Collider emittance, luminosity, collider, radiation 516
 
  • M.A. Valdivia García, F. Zimmermann
    CERN, Meyrin, Switzerland
 
  Direct s-channel Higgs production in e+e− collisions is of interest if the collision energy spread can be comparable to the natural width of the standard model Higgs boson. At the Future Circular e+e Collider (FCC-ee), a monochromatization scheme could be employed in order to reduce the collision energy spread to the target value. This may be achieved by introducing a non-zero horizontal dispersion of opposite sign for the two colliding beams at the interaction point. In this case, the beamstrahlung increases the horizontal emittance in addition to energy spread and bunch length.  The vertical emittance could either be tuned to a certain minimum value, possibly limited by the diagnostics resolution, or it could scale linearly with the horizontal emittance. For the FCC-ee at 62.5 GeV beam energy, we optimize the IP optics and beam parameters, considering these two different assumptions for the vertical emittance. We derive the maximum achievable luminosity as a function of collision energy spread for either case.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP035  
About • paper received ※ 16 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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MOPRB024 Beam-Gas and Beam-Thermal Photon Scattering in CEPC scattering, background, detector, factory 626
 
  • S. Bai, J. Gao, H. Geng, D. Wang, Y. Wang, C.H. Yu, Y. Zhang
    IHEP, Beijing, People’s Republic of China
  • Y. Zhang
    University of Chinese Academy of Sciences, Beijing, People’s Republic of China
 
  The Circular Electron Positron Collider (CEPC) is a proposed Higgs factory with center of mass energy of 240 GeV to measure the properties of Higgs boson and test the standard model accurately. Beam loss background in detectors is an important topic at CEPC. Beam-Gas scattering (BG) and Beam-Thermal photon scattering (BTH), although not so serious as Radiative Bhabha scattering (RBB) and Beamstrahlung (BS), are also important components of the beam induced backgrounds at CEPC due to the beam lifetime. In this paper, we evaluated the beam-gas and beam-thermal photon scattering in simulation and designed collimators to suppress the radiation level on the machine and the detector.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB024  
About • paper received ※ 28 April 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPRB052 Gamma Factory at CERN: Design of a Proof-of-Principle Experiment laser, experiment, electron, cavity 685
 
  • Y. Dutheil, R. Alemany-Fernández, H. Bartosik, N. Biancacci, R. Bruce, P. Czodrowski, V. Fedosseev, B. Goddard, S. Hirlaender, J.M. Jowett, R. Kersevan, M. Kowalska, M. Lamont, D. Manglunki, J. Molson, A.V. Petrenko, M. Schaumann, F. Zimmermann
    CERN, Geneva, Switzerland
  • S. E. Alden, A. Bosco, S.M. Gibson, L.J. Nevay
    JAI, Egham, Surrey, United Kingdom
  • A. Apyan
    ANSL, Yerevan, Armenia
  • E.G. Bessonov
    LPI, Moscow, Russia
  • A. Bosco, S.M. Gibson, L.J. Nevay
    Royal Holloway, University of London, Surrey, United Kingdom
  • F. Castelli
    Università degli Studi di Milano, Milano, Italy
  • F. Castelli, C. Curatolo, L. Serafini
    INFN-Milano, Milano, Italy
  • K. Kroeger
    FSU Jena, Jena, Germany
  • A. Martens
    LAL, Orsay, France
  • V. Petrillo
    Universita’ degli Studi di Milano, Milano, Italy
  • M. Sapinski, T. Stöhlker
    GSI, Darmstadt, Germany
  • G. Weber
    IOQ, Jena, Germany
  • Y.K. Wu
    FEL/Duke University, Durham, North Carolina, USA
 
  The Gamma Factory (GF) initiative proposes to create novel research tools at CERN by producing, accelerating and storing highly relativistic partially stripped ion beams in the LHC rings and by exciting their atomic degrees of freedom by lasers, to produce high-energy photon beams. Their intensity would be several orders of magnitude higher than those of the presently operating light sources in the particularly interesting gamma-ray energy domain reaching up to 400 MeV. In this energy domain, the high-intensity photon beams can be used to produce secondary beams of polarized electrons, polarized positrons, polarized muons, neutrinos, neutrons and radioactive ions. Over the years 2017-2018 we have demonstrated that these partially stripped ion beams can be successfully produced, accelerated and stored in the CERN accelerator complex, including the LHC. The next step of the project is to build a proof of principle experiment in the SPS to validate the principal GF concepts. This contribution will present the initial conceptual design of this experiment along with its main challenge - the demonstration of the fast cooling method of partially stripped ion beams.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB052  
About • paper received ※ 19 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPRB056 THz Radiator Based on Photonic Band Gap Crystal for SwissFEL electron, GUI, experiment, FEL 693
 
  • L. Shi, R. Ischebeck, S. Reiche
    PSI, Villigen PSI, Switzerland
 
  Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 701647.
The electromagnetic radiation in 1-20 THz has many unique properties when it interacts with matter due to its non-ionizing excitation in matter. Especially the dynamics of the excited matter can be probed with the help of X-ray pulses at a free electron laser facility, e.g. SwissFEL, to deepen our understanding of a wide range of phenomena. Due to its high research potential, various means of THz generation have been proposed and demonstrated. We investigate preliminarily here its generation based on a relativistic electron bunch and a photonic band gap crystal (PBG) made of dielectric rods. The PBG provides additional degrees of freedom for the THz pulse tuning. Additionally, the unwanted radiation parts can be damped by the structure in order to minimize the deleterious beam dynamics effects. The crystal also promises the integration of generation, filtering and coupling for transport into a single piece.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB056  
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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MOPRB088 Study of Fluctuations in Undulator Radiation in the IOTA Ring at Fermilab experiment, undulator, electron, radiation 777
 
  • I. Lobach
    University of Chicago, Chicago, Illinois, USA
  • A. Halavanau, Z. Huang, V. Yakimenko
    SLAC, Menlo Park, California, USA
  • K. Kim
    ANL, Argonne, Illinois, USA
  • V.A. Lebedev, S. Nagaitsev, A.L. Romanov, G. Stancari, A. Valishev
    Fermilab, Batavia, Illinois, USA
  • A.Y. Murokh
    RadiaBeam, Los Angeles, California, USA
  • T.V. Shaftan
    BNL, Upton, Long Island, New York, USA
 
  We study turn-by-turn fluctuations in the number of emitted photons in an undulator, installed in the IOTA electron storage ring at Fermilab with an InGaAs PIN photodiode and an integrating circuit. Our study was motivated by the previous experiment *. We propose a theoretical model for the experimental data from * and in our own experiment we attempted to verify the model in an independent and more systematic way. Moreover, these fluctuations are an interesting subject for a study by itself, since they act as a seed for SASE in FELs. We improve the precision of the measurements from * by subtracting the average signal amplitude using a comb filter with a one-turn IOTA delay, and by using a special algorithm for noise subtraction. We obtain a reasonable agreement between our theoretical model and experiment. Along with repeating the experiment from *, which was performed at a constant beam current, we also collect data for fluctuations in undulator light at different beam current values. Lastly, in our experiment we were able to see the transition from Poisson statistics to Super-Poisson statistics for undulator light, whereas in * only the latter statistics was observed.
* M. Teich et al., PRL, vol. 65, no. 27, p. 3393 (1990).
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB088  
About • paper received ※ 14 May 2019       paper accepted ※ 18 May 2019       issue date ※ 21 June 2019  
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MOPRB089 Experimental Study of a Single Electron in a Storage Ring via Undulator Radiation electron, undulator, experiment, radiation 781
 
  • S. Nagaitsev, A.L. Romanov, G. Stancari
    Fermilab, Batavia, Illinois, USA
  • A. Arodzero, A.Y. Murokh, M. Ruelas
    RadiaBeam, Santa Monica, California, USA
  • I. Lobach
    University of Chicago, Chicago, Illinois, USA
  • T.V. Shaftan
    BNL, Upton, Long Island, New York, USA
 
  A single electron orbiting around a ring and emitting single quanta at the rate of about one event per hundred turns could produce a wealth of information about physical processes in large traps (i.e. storage rings) for charged particles. It should be noted that Paul and Penning traps in the 1980s led to the Nobel prize for studying state and motion of single quantum particles, and just recently the Penning trap technique has enabled the measurement of a single proton magnetic moment with an unprecedented precision of 10 decimal places. The information from the storage ring traps could also be used for characterization of a quantum system as well as the "trap" itself, i.e. measuring properties of the storage ring lattice and electron interaction with the laser fields. Although, the interest in single electron quantum processes today is mostly academic in nature, the diagnostics and methodology developed for single electron radiation studies could find subsequent applications in a variety of applied disciplines in quantum technology, including quantum communications and quantum computing.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB089  
About • paper received ※ 15 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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TUYPLM1 XFEL Performance Achieved at PAL-XFEL FEL, undulator, electron, emittance 1182
 
  • H. Heo, M.-H. Cho, J.H. Han, H.-S. Kang, C. Kim, G. Kim, M.J. Kim, J.H. Ko, H.-S. Lee, C.-K. Min, I.H. Nam, K.-H. Park, C.H. Shim, H. Yang
    PAL, Pohang, Kyungbuk, Republic of Korea
 
  The hard X-ray free electron laser at Pohang Accelerator Laboratory (PAL-XFEL) successfully completed the commissioning of SASE and started user operation in late 2016. Since then, the facility has demonstrated excellent stability with very small timing jitter of about 20 fs, and commissioned the self-seeding system over a wide range of photon energies, etc. The talk will provide an overview of the last three years at the PAL-XFEL, including some detailed experimental results, as well as future prospects for the laboratory.  
slides icon Slides TUYPLM1 [7.516 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUYPLM1  
About • paper received ※ 20 May 2019       paper accepted ※ 24 May 2019       issue date ※ 21 June 2019  
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TUZPLS2 Beam Dynamics Study in the HEPS Storage Ring lattice, storage-ring, emittance, brightness 1203
 
  • Y. Jiao, X. Cui, Z. Duan, Y.Y. Guo, P. He, X.Y. Huang, D. Ji, H.F. Ji, C. Li, J.Y. Li, X.Y. Li, C. Meng, Y.M. Peng, Q. Qin, S.K. Tian, J.Q. Wang, N. Wang, Y. Wei, G. Xu, H.S. Xu, F. Yan, C.H. Yu, Y.L. Zhao
    IHEP, Beijing, People’s Republic of China
 
  The High Energy Photon Source (HEPS) is the first high-energy diffraction-limited storage ring (DLSR) light source to be built in China, with a natural emittance of a few tens of pm rad and a circumference of 1360.4 m. After 10 years’ evolution, the accelerator physics design of the HEPS has been basically determined, with the ring consisting of 48 hybrid-7BAs with anti-bends and super-bends. This paper will discuss the accelerator physics studies of the HEPS storage ring, covering issues of lattice design, nonlinear optimization, collective effects, error correction, insertion devices, etc.  
slides icon Slides TUZPLS2 [9.517 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUZPLS2  
About • paper received ※ 15 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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TUPMP007 DYVACS (DYnamic VACuum Simulation) Code: Calculation of Gas Density Profiles in Presence of Electron Cloud electron, vacuum, proton, experiment 1244
 
  • G. Sattonnay, S. Bilgen, B. Mercier
    LAL, Orsay, France
  • V. Baglin
    CERN, Meyrin, Switzerland
 
  The computation of residual gas density profiles in particle accelerators is an essential task to optimize beam pipes and vacuum system design. In a hadron collider such as the LHC, the beam induces dynamic effects due to ion, electron and photon-stimulated gas desorption. The well-known VASCO* code developed at CERN in 2004 (and then PyVASCO**) is already used to estimate vacuum stability and density profiles in steady state conditions. Nevertheless, some phenomena are not taken into account such as the ionization of residual gas by the electron clouds. Therefore, we propose an upgrade of this code by introducing electron cloud maps*** to estimate the electron density and the ionization of gas by electrons, leading to an increase of both electron- and ion-induced desorption. Results obtained with the new code (called DYVACS for DYnamic VACuum Simulation) will be compared to pressure measurements in the VPS sector**** of the LHC.
* A. Rossi, Tech. Rep., LHC Proj. Note 341
** I. Aichinger, et al arXiv:1707.07525
*** T. Demma et al Phys. Rev. Acceler. and Beams 10, 114401 (2007)
**** B. Henrist et al, Proc. IPAC2014, Dresden
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP007  
About • paper received ※ 15 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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TUPMP018 Feasibility Tests of a Vacuum System for SPring-8-II vacuum, hardware, multipole, operation 1272
 
  • K. Tamura, T. Bizen, M. Masaki, H. Ohkuma, M. Oishi, M. Shoji, S. Takahashi, Y. Taniuchi
    JASRI, Hyogo, Japan
  • T. Bizen, M. Oishi, S. Takahashi
    RIKEN SPring-8 Center, Hyogo, Japan
 
  For SPring-8-II, the major upgrade of SPring-8, a test half-cell including permanent/electro magnets and a vacuum system was constructed, and hardware feasibility tests have been performed since 2017. Features of the SPring-8-II vacuum system are 1) introduction of the concept of a stainless steel 12 m-long integral chamber (LIC) with a welded structure, and 2) adoption of ex-situ baking of the chamber. The 12 m LIC with a narrow aperture, flangeless structure and a minimum number of bellows was designed so that the vacuum system could be installed without interference with the magnets of a narrow bore diameter aligned on girders with a severe packing factor. For replacement of the existing system with a new one in a short black-out period, the 12 m LIC is planned to be moved into the accelerator tunnel with keeping ultra-high vacuum (UHV) by closing thin gate valves at both ends, after evacuation to UHV by ex-situ baking and NEG activation. This presentation will overview the vacuum system, mainly the 12 m LIC, developed for the test half-cell, and describe the vacuum performance and the result of the assembly test conducted with the permanent/electro magnets.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP018  
About • paper received ※ 15 May 2019       paper accepted ※ 17 May 2019       issue date ※ 21 June 2019  
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TUPMP019 Vacuum Performance of the NEG-coated Chamber for U#19 at PF-ring vacuum, simulation, MMI, undulator 1276
 
  • Y. Tanimoto, T. Honda, X.J. Jin, T. Nogami, R. Takai, M. Yamamoto
    KEK, Ibaraki, Japan
 
  At the Photon Factory storage ring (PF-ring) in KEK, a new APPLE-II type elliptically polarizing undulator (U#19) was installed in October 2018. The U#19 vacuum chamber is 4.1 meters in length, and the beam channel with a 15x90 elliptical profile and two cooling-water channels alongside were formed by extrusion of A6060-T6 aluminum alloy. The inner surface of the beam channel is coated with a Ti-Zr-V Non-Evaporable Getter (NEG) thin film, as it has a high effective pumping speed and a low Photon Stimulated Desorption (PSD) yield. After the installation of the U#19, the neighboring uncoated chambers and vacuum components were baked out at 200 °C for 44 hours, and then the NEG coating was activated at 160 °C for 48 hours. As a result, the pressures in the neighboring chambers reached as low as 10-8 Pa. The conditioning of the vacuum chambers with irradiation of Synchrotron radiation evolved favorably as had been expected by a combined simulation of Synrad and Molflow, leading to a satisfactory recovery of the beam lifetime. Vacuum performance of the NEG-coated chamber was assessed especially by means of a residual gas analysis, and the properties of the NEG film were characterized by surface analyses including SEM, EDX, and XRD.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP019  
About • paper received ※ 16 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPMP035 Design of the Vacuum System of the FCC-ee Electron-Positron Collider collider, vacuum, dipole, quadrupole 1319
 
  • R. Kersevan, C. Garion
    CERN, Geneva, Switzerland
 
  The Future Circular Collider (FCC) Design Study includes the twin storage ring (FCC-ee) where electrons and positrons are stored and made to collide inside two detectors. The vacuum system of FCC-ee must be designed in order to deal with a lower-energy (45.6 GeV), high-current (1390 mA) Z-pole machine and at a later stage with a higher-energy (182.5 GeV) low-current (5.4 mA). The former machine is the most challenging one from the point of view of vacuum, since the photon-stimulated desorption (PSD) generated by the copious synchrotron radiation (SR) fans is quite large. While several concepts have been considered at the beginning, the design retained for the Conceptual Design Report (CDR) is one where the cross-section of the vacuum chamber (VC) in the arcs is a scaled-down version of the one implemented in the SUPERKEKB collider. Contrary to SUPERKEKB tough, the SR fans are absorbed by many short absorbers, with average spacing of 5.8 m. This allow a localization of the PSD gas load and to place lumped pumps in front of the SR absorbers, to maximize the pumping efficiency. The VC design is compatible with the design of the common-yoke dipoles and quadrupoles. The VC material is copper alloy. Optimization of the pressure profiles has been carried out by means of extensive coupled montecarlo simulations, for SR and molecular flow. For the higher energy versions of the machine, for which the SR spectra are characterized by critical energies well above the Compton edge, the localized absorbers facilitate also shielding the tunnel and any radiation-sensitive machine components from X-ray photon damage, by installing short high-Z material around the absorbers. The major features of the CDR relevant for vacuum will be highlighted in the paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP035  
About • paper received ※ 13 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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TUPMP036 Results on the FCC-hh Beam Screen Sawtooth at the Kit Electron Storage Ring Kararesults on the Fcc-Hh Beam Screen Sawtooth at the Kit Electron Storage Ring Kara radiation, vacuum, experiment, electron 1323
 
  • L.A. Gonzalez, V. Baglin, I. Bellafont, P. Chiggiato, C. Garion, R. Kersevan
    CERN, Geneva, Switzerland
  • I. Bellafont, F. Pérez
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  • S. Casalbuoni, E. Huttel
    KIT, Eggenstein-Leopoldshafen, Germany
 
  Funding: * The European Circular Energy-Frontier Collider Study (EuroCirCol) project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant No 654305.
In the framework of the EuroCirCol collaboration (work package 4 "Cryogenic Beam Vacuum System"), the fabrication of the FCC-hh beam screen (BS) prototype has been carried out with the aim of testing it at room temperature on the Karlsruhe Institute of Technology (KIT) 2.5 GeV electron storage ring KARA (KArlsruhe Research Accelerator) light source. The BS prototype was tested on a beamline installed by the collaboration, named as BEam Screen TEstbench EXperiment (BESTEX). KARA has been chosen because its synchrotron radiation (SR) spectrum, photon flux and power match quite well the one foreseen for the 50+50 TeV FCC-hh proton collider. The BS prototype (2 m in length) was manufactured according to the base line design (BD) of the FCC-hh BS. It implements a saw-tooth profile designed to absorb the SR generated at the bending magnets. Also, a laser-ablated anti-electron cloud surface texturing [2] was applied at the BS inner walls. We present here the results obtained at BESTEX and the comparison of the results obtained during irradiation of the saw-tooth profile at different geometric configurations.
This activity has been carried out in the framework of the EuroCirCol* collaboration (work package 4 "Cryogenic Beam Vacuum System").
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP036  
About • paper received ※ 13 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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TUPMP037 Recent Developments of Monte-Carlo Codes Molflow+ and Synrad+ simulation, vacuum, synchrotron, synchrotron-radiation 1327
 
  • R. Kersevan, M. Ady
    CERN, Geneva, Switzerland
 
  Molflow+ and Synrad+ are Monte Carlo simulation tools for ultra-high vacuum and synchrotron radiation, respectively. Over the years they have become a common tool for designing and analysing the vacuum system of particle accelerators. This contribution gives a short summary about new features added since IPAC-14*. Some highlights: In traditional Monte Carlo simulations, one simulated ’virtual’ particle represents a given number of physical molecules or photons. This is a weakness where the pressure or flux of the simulated system spans across multiple orders of magnitude. Synrad now supports low flux mode, a weighed Monte Carlo technique where the represented number of photons is reduced at every reflection, providing significantly better statistics at low flux regions. As for Molflow+, angle maps allow recording the molecules, directional distribution at any point, and then desorb a reduced gas quantity according to the recording. In linear systems, this allows iterative simulations that have been proven to treat systems up to 7 orders of magnitude of pressure difference. Without the new technique the computing time would be prohibitively slow on desktop computers, which is what most users of the two codes use. Both codes now have a built-in geometry builder that allows creating simple models through a set of 3D operations, and modifying those imported from CAD tools. Molflow+ has recently become open source, and it has been made compatible with, and tested on different versions of Linux and macOS. Examples of application of Molflow+ to novel Beam Gas Curtain detector and the design of the FCC-ee vacuum system will be given, alongside with some benchmarking runs against data published in literature.
* M. Ady, R. Kersevan, "Introduction to the Latest Version of the Test-particle Monte Carlo Code Molflow+", Proc. IPAC’14, Dresden, Germany, June 2014, pp. 2348-2350.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP037  
About • paper received ※ 13 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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TUPMP038 Summary of Modelling Studies on the Beam Induced Vacuum Effects in the FCC-hh vacuum, electron, collider, synchrotron 1331
 
  • I. Bellafont, R. Kersevan, L. Mether
    CERN, Geneva, Switzerland
 
  Funding: The European Circular Energy-Frontier Collider Study (EuroCirCol) project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant No 654305.
EuroCirCol is a conceptual design study of a Future Circular Collider (FCC-hh) which aims to expand the current energy and luminosity frontiers that the LHC has established. The vacuum chamber of this 50 TeV, 100 km collider, will have to cope with unprecedented levels of synchrotron radiation power for proton colliders, dealing simultaneously with a tighter magnet aperture. Since the high radiation power and photon flux will release large amounts of gas into the system, the difficulty to keep a low level of residual gas density increases considerably compared with the LHC. This article presents a study of the beam induced vacuum effects for the FCC-hh novel conditions, the different phenomena which, owing to the presence of the beam, have an impact on the vacuum level of the accelerator. To achieve this, a novel beam screen has been proposed, featuring specific mitigating measures aimed at dealing with the beam induced effects. It is concluded that thanks to the new beam screen design, the vacuum level in the FCC-hh shall be adequate, allowing to reach the molecular density requirement of better than 1015 H2/m3 with baseline beam parameters within the first months of conditioning.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP038  
About • paper received ※ 10 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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TUPMP044 Special Aluminum Gasket Sealing of Non-circular Profile Flanges for the Accelerator UHV Systems vacuum, impedance, experiment, emittance 1347
 
  • G.Y. Hsiung
    NSRRC, Hsinchu, Taiwan
 
  Most of the beam ducts for the accelerators are not regularly the circular profile. Unfortunately, the conflat (CF-) flanges and the gaskets with non-circular profile were not commercially available. Besides, additional RF-contact bridges between the flanges must be built in for mitigating the impedance from the flange-gaps. In this presentation, various types of the aluminum (Al-) gaskets designed for the non-circular profile Al-flanges for the accelerator ultrahigh vacuum (UHV) systems are introduced. The surface of the Al-flange is flat to accommodate the special Al-gasket with knife edges for the sealing. Both the flange and gasket are manufactured by the oil-free Ethanol-CNC-machining process that any non-circular profile, e.g. rectangular, race-track, key-hole, etc., flanges can be precisely produced. The inner diameters of the gasket just suits those of the flanges that the impedance from the gap is significantly reduced. The flanges and gaskets after oil-free machining can be assembled immediately without any chemical cleaning. The experimental results for the as-mentioned non-circular profile Al-flanges reveal the UHV quality at pressure < 20 nPa after vacuum baking.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP044  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPMP046 Improvement the Bending Magnet Power Supply Performance for TPS Storage Ring power-supply, storage-ring, feedback, controls 1353
 
  • B.S. Wang, C.H. Huang, J.C. Huang, C.Y. Liu, K.-B. Liu, Y.S. Wong
    NSRRC, Hsinchu, Taiwan
 
  In the TPS (Taiwan Photon Source) facility, current stability of the electron beam depends on the bending magnet power supply and an orbit FOFB system to compensate the magnetic field. Due to the output current stability of the bending magnet power supply drifts with temperature so the orbit FOFB system should be applied to fine tune magnetic field and the photon beam should circulate in storage ring. In this paper, to stabilize the temperature of regulation circuit’s temperature box of the bending magnet power supply, the long-term output current stability is improve from ± 50ppm to ± 10ppm, and orbit FOFB system substantially reduce the tune X of beam position, effectively increasing the beam current stability and quality.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP046  
About • paper received ※ 12 April 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPMP050 Conceptual Design of the Diamond-II Vacuum System vacuum, storage-ring, target, controls 1362
 
  • M.P. Cox, C. Burrows, A.G. Day, J. A. Dymoke-Bradshaw, R.K. Grant, N.P. Hammond, X. Liu, A.G. Miller, H.S. Shiers, N. Warner
    DLS, Oxfordshire, United Kingdom
 
  The conceptual design of the vacuum system for the Diamond-II storage ring upgrade is described. Due to the small vessel cross section, typically 20 mm inside diameter (ID), and the consequent conductance limitation, distributed pumping is provided by non-evaporable getter (NEG) coating supplemented by ion pumps at high gas load locations. In-situ bakeout is incorporated to allow rapid recovery from both planned vacuum interventions and unplanned vacuum events. The vacuum vessels are constructed mainly from copper alloy while stainless steel is used in regions of AC magnets requiring low electrical conductivity. The proposed layout, engineering and build sequence of the vacuum system are described along with gas flow simulations confirming the vacuum performance advantages of NEG-coated vessels compared with uncoated vessels.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP050  
About • paper received ※ 14 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPGW013 Tune and Chromaticity Optimization at Bessy II for the Transverse Resonant Island Bucket Optics optics, simulation, resonance, emittance 1411
 
  • F. Armborst, P. Goslawski, A. Jankowiak
    HZB, Berlin, Germany
 
  Funding: Federal Ministry of Education and Research
Transverse Resonant Island Buckets (TRIBs *) correspond to a second stable orbit, longitudinally winding around the core orbit in the transverse x-x-phasespace. The exploitation possibilities for stable TRIBs are under investigation at the third generation light source BESSY II in Berlin. The applicability for bunch separation is a main subject of these studies. Stable operation of TRIBs optics with a single or few bunches on the second orbit and a multibunch train on the main orbit has been shown **. Photons emitted on the second orbit are well separated from those of the main orbit at all beamlines. This provides the possibility of bunch separation by beamline adjustment for the timing community without significant impact on the average brightness for other users. Simulations based on linear optics from closed orbits (LOCO) and on nonlinear optics derived from the measured chromaticity and tune shift with action (TSWA) predict this separation well. Friendly user experiments in 2018 confirmed these results. The scheduled upgrade BESSY VSR *** features simultaneously stored long and short bunches. Then TRIBs optics would in principle enable the separation of the different bunches at every beamline offering unique possibilities to our users. Simulations and measurements aiming to investigate further possible optimization of the TRIBs optics are presented.
* F. Armborst, P. Goslawski et al, DOI: 10.18429/JACoW-IPAC2018-TUPML052
** P. Goslawski, F. Armborst et al. DOI: 10.18429/JACoW-IPAC2017-WEPIK057
*** A. Jankowiak et al., DOI: 10.5442/R0001
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW013  
About • paper received ※ 14 May 2019       paper accepted ※ 18 May 2019       issue date ※ 21 June 2019  
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TUPGW046 Progress of Lattice Design and Physics Studies on the High Energy Photon Source lattice, storage-ring, booster, injection 1510
 
  • Y. Jiao, X. Cui, Z. Duan, Y.Y. Guo, P. He, X.Y. Huang, D. Ji, C. Li, J.Y. Li, X.Y. Li, C. Meng, Y.M. Peng, Q. Qin, S.K. Tian, J.Q. Wang, N. Wang, Y. Wei, G. Xu, H.S. Xu, F. Yan, C.H. Yu, Y.L. Zhao
    IHEP, Beijing, People’s Republic of China
 
  The High Energy Photon Source (HEPS) is an ul-tralow-emittance, kilometer-scale storage ring light source to be built in China. In this paper we will introduce the progress of the physics design and related studies of HEPS over the past year, covering issues in storage ring lattice design, injection and injector design, insertion device effects, error study and lattice calibration, collective effects, etc.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW046  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPGW085 A Hard X-Ray Compact Compton Source at CBETA electron, laser, scattering, brilliance 1604
 
  • K.E. Deitrick, C. Franck, G.H. Hoffstaetter, V.O. Kostroun, K.W. Smolenski
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • J. Crone, H.L. Owen
    UMAN, Manchester, United Kingdom
  • B.D. Muratori
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
 
  Compton backscattering at energy recovery linacs (ERLs) promises high flux, high energy x-ray sources in the future, made possible by high quality, high repetition rate electron beams produced by ERLs. CBETA, the Cornell-BNL ERL Test Accelerator currently being built and commissioned at Cornell, is an SRF multi-turn ERL using Non-Scaling Fixed Field Alternating-gradient (NS-FFA) arcs. CBETA has high quality design parameters with an anticipated top energy of 150 MeV on the fourth pass. The expected parameters of a Compton source at CBETA include a top x-ray energy of over 400 keV with a flux on the order of 1012 ph/s. In this paper, we present anticipated parameters and potential applications in science and engineering for this source.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW085  
About • paper received ※ 14 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPGW106 Present Status of the PF-ring and PF-AR Operations operation, injection, undulator, ECR 1654
 
  • R. Takai, T. Honda, Y. Kobayashi, S. Nagahashi
    KEK, Ibaraki, Japan
 
  The Photon Factory at KEK has been managing two synchrotron radiation sources, the PF-ring and PF-AR, for over 30 years. Although their operation time has been decreasing in recent years for budget reasons, continuous efforts to improve their performance have been made. In this paper, the operational status of these light sources for FY2018 is described. At the PF-ring, a first-generation undulator was renewed with the beamline components. A vacuum chamber for the new undulator was applied the NEG coating on the inner surface. This is the first attempt in Japanese light sources that the NEG-coated chamber is used for undulators. At the PF-AR, the top-up injection using the direct beam transport line was introduced to the user operation for the first time. Since modification of the beam injector LINAC for enabling simultaneous injection to the four different rings (the PF-ring, PF-AR, SuperKEKB HER and LER) was completed, this top-up operation no longer disturbs the operation of the other three rings. A low-energy operation of the PF-AR was also tested to secure more operation time within the limited budget.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW106  
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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TUPGW109 Conceptual Design of Vacuum Chamber for SPS-II Storage Ring vacuum, storage-ring, impedance, emittance 1666
 
  • T. Phimsen, S. Chaichuay, N. Juntong, P. Klysubun, S. Prawanta, P. Sudmuang, P. Sunwong
    SLRI, Nakhon Ratchasima, Thailand
  • R. Deepan, A. Khamkham
    Suranaree University of Technology, Nakhon Ratchasima, Thailand
 
  The SPS-II is a 3 GeV ultralow emittance light source which is now under studied and designed by Thailand Synchrotron Light Research Institute (SLRI). The SPS-II storage ring is based on Double-Triple Bend Achromat (DTBA) cell with a circumference of 321.3 m aiming for horizontal emittance of less than 1 nm-rad. The compact lattice leaves narrow space for vacuum components. The small gap between poles of the magnets requires narrow vacuum chambers and limits the conductance of the chambers. The chambers will be made by stainless steel with a thickness of 1.5 mm. the cross section of beam duct is 40 mm × 16 mm elliptical shape. The bending chamber is designed as a long triangular chamber such that photon absorber can be installed as far from the light source as possible to lower the power density of the heat load. The overview of designed vacuum system for the SPS-II is presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW109  
About • paper received ※ 14 May 2019       paper accepted ※ 18 May 2019       issue date ※ 21 June 2019  
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TUPRB002 The Conceptual Design of a 36 GHz RF Undulator undulator, cavity, electron, GUI 1676
 
  • D. Zhu
    ASCo, Clayton, Victoria, Australia
  • A.W. Cross, L. Zhang
    USTRAT/SUPA, Glasgow, United Kingdom
  • Y.E. Tan
    AS - ANSTO, Clayton, Australia
 
  The CompactLight project supported by European H2020 is to design a hard X-ray FEL facility beyond today’s state of the art. The project integrates photo injector, X-band acceleration and innovative compact short-period undulators together to make the machine more compact. RF undulator has an extraordinary advantage of working at very short undulator period. A conceptual design for a RF undulator at 36 GHz using a corrugated cylindrical waveguide operating in the HE11 mode is presented in this paper. Based on beam dynamics simulation and photon beam radiation simulations, the possibility of RF undulator to be used in CompactLight project is evaluated.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB002  
About • paper received ※ 15 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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TUPRB005 Photon Polarisation Modelling of APPLE-II EPUs polarization, undulator, operation, simulation 1687
 
  • M.J. Sigrist, C.K. Baribeau, T.M. Pedersen
    CLS, Saskatoon, Saskatchewan, Canada
 
  The CLS is currently commissioning two APPLE-II in-sertion devices (IDs), see [1], and constructing two more that allow for operation in ’universal mode’, i.e. selecting arbitrary photon polarisation parameters. Two of these devices will operate in the soft x-ray range where there is expected to be a significant change to polarisation at the sample due to transmission effects of the beam line op-tics. Arbitrary polarisation selection of the ID will counter transmission effects and enable circular polarisation at the sample position. A polarisation model of the device is derived which allows for the calculation of both the Stokes parameters and photon energy for any set point of ID gap and phase. Numerical solutions of these equa-tions allow the calculation of gap and phase set points for any desired photon energy or polarisation. The results of the polarisation model are compared with numerical simulations of the synchrotron radiation calculated using measured magnetic fields at various polarisation modes.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB005  
About • paper received ※ 13 May 2019       paper accepted ※ 18 May 2019       issue date ※ 21 June 2019  
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TUPRB008 LUXE - a QED Experiment at the European XFEL experiment, FEL, electron, laser 1694
 
  • F. Burkart, R.W. Aßmann, R. Brinkmann, W. Decking, N. Golubeva, B. Heinemann, M. Hüning, J. List, M. Wing
    DESY, Hamburg, Germany
  • M. Wing
    UCL, London, United Kingdom
 
  The proposed experiment aims to measure QED in the presence of strong fields and above the Schwinger critical field. An experiment is being considered at the European XFEL, which should be able to measure non-perturbative QED and its transition from the perturbative regime. This paper presents the current status of the LUXE (Laser und XFEL Experiment) design study. First layout considerations; accelerator beam line design, electron and laser beam parameters, radioprotection issues and first results of the start to end simulations will be presented and discussed in detail. An outlook concerning the implementation into the XFEL schedule and timeline of this experiment will be given.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB008  
About • paper received ※ 14 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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TUPRB020 Status of the European XFEL FEL, operation, electron, MMI 1721
 
  • W. Decking, F. Brinker, L. Fröhlich, R. Kammering, T. Limberg, S. Liu, D. Nölle, M. Omet, M. Scholz, T. Wamsat
    DESY, Hamburg, Germany
 
  The European XFEL is a Hard X-ray Free Electron Laser based on superconducting accelerator technology. In operation since 2017, it now serves 3 FEL beamlines simultaneously for user experiments. We will report on the present operation of the linear accelerator, the beam distribution to the various beamlines and the performance of the FEL radiators.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB020  
About • paper received ※ 15 May 2019       paper accepted ※ 17 May 2019       issue date ※ 21 June 2019  
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TUPRB022 Triple Period Undulator undulator, radiation, vacuum, operation 1728
 
  • A. Meseck, J. Bahrdt, W. Frentrup, M. Huck, C. Kuhn, C. Rethfeldt, M. Scheer
    HZB, Berlin, Germany
  • E.C.M. Rial
    DLS, Oxfordshire, United Kingdom
 
  Insertion devices are one of the key components of modern synchrotron radiation facilities. They allow for generation of radiation with superior properties enabling experiments in a variety of disciplines, such as chemistry, biology, crystallography and physics to name a few. For future cutting edge experiments in soft and tender x-rays users require high flux and variable Polarization over a wide photon energy range independent of other desired properties like variable pulse length, variable timing or Fourier transform limited pulses. In this paper, we propose a novel ID-structure, called Triple Period Undulator (TPU), which allow us to deliver a wide energy range from a few ten eV to a few keV at the same beamline with high flux and variable Polarization. The TPU are particularly interesting in context of BESSY III, the successor facility of BESSY II.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB022  
About • paper received ※ 15 May 2019       paper accepted ※ 18 May 2019       issue date ※ 21 June 2019  
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TUPRB023 Considerations for the Ultrahard X-ray Undulator Line of the European XFEL undulator, FEL, electron, operation 1732
 
  • E. Schneidmiller, V. Balandin, W. Decking, M. Dohlus, N. Golubeva, D. Nölle, M.V. Yurkov, I. Zagorodnov
    DESY, Hamburg, Germany
  • G. Geloni, Y. Li, S. Molodtsov, J. Pflüger, S. Serkez, H. Sinn, T. Tanikawa, S. Tomin
    EuXFEL, Schenefeld, Germany
 
  The European XFEL is a multi-user X-ray FEL facility based on superconducting linear accelerator. Presently, three undulators (SASE1, SASE2, SASE3) routinely deliver high-brightness soft- and hard- X-ray beams for users. There are two empty undulator tunnels that were originally designed to operate with spontaneous radiators in the range 20-90 keV. We consider, instead a possible installation of two FEL undulators. One of them (SASE4) is proposed for operation in a standard (7-25 keV) range as well as in ultrahard (25-100 keV) regime. We discuss a possible location and length of SASE4, modifications of electron beam transport, beam dynamics, choice of undulator technology, different operation modes (SASE and advanced lasing concepts) etc.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB023  
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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TUPRB025 Harmonic Lasing of the European XFEL in the Angstrom Regime FEL, undulator, experiment, operation 1740
 
  • E. Schneidmiller, F. Brinker, W. Decking, D. Nölle, M.V. Yurkov, I. Zagorodnov
    DESY, Hamburg, Germany
  • N. Gerasimova, J. Grünert, N.G. Kujala, J. Laksman, Y. Li, J. Liu, Th. Maltezopoulos, I. Petrov, L. Samoylova, S. Serkez, H. Sinn, F. Wolff-Fabris
    EuXFEL, Hamburg, Germany
 
  Harmonic lasing in XFELs is an opportunity to extend the photon energy range of existing and planned X-ray FEL user facilities. Contrary to nonlinear harmonic generation, harmonic lasing can provide much more intense, stable, and narrow-band FEL beam. Another interesting application is Harmonic Lasing Self-Seeding (HLSS) that allows to improve longitudinal coherence and spectral power of a Self-Amplified Spontaneous Emission (SASE) FEL. This concept was successfully tested at FLASH2 in the range of 4.5 - 15 nm and at PAL XFEL at 1 nm. In this contribution we present recent results from the European XFEL where we successfully demonstrated operation of HLSS FEL at 5.9 A, thus pushing harmonic lasing for the first time into the Angstrom regime.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB025  
About • paper received ※ 09 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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TUPRB031 FERMI Configuration for the Echo Enabled Harmonic Generation Experiment laser, FEL, electron, experiment 1752
 
  • E. Allaria, D. Castronovo, M. Cautero, I. Cudin, M.B. Danailov, B. Diviacco, L. Giannessi, M. Veronese, M. Zangrando
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
 
  The FERMI FEL-2 undulator line, normally operated in the double stage high gain harmonic generation with the fresh bunch (HGHG-FB) has been temporary modified to allow operating the FEL in the Echo Enabled Harmonic Generation (EEHG) scheme. An increase of the dispersion in the delay-line was required together with a replacement of the second stage modulator allowing the electron beam to resonantly interact with a second seed laser. Another critical component of the EEHG setup is a new manipulator installed in the delay-line chicane and hosting additional diagnostic components. In this work we describe in some detail these new components that allowed a successful demonstration of the EEHG at harmonics as high as 101.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB031  
About • paper received ※ 17 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPRB047 Proposal of the Reflection Hard X-Ray Self-Seeding at the SHINE Project FEL, undulator, polarization, lattice 1792
 
  • T. Liu, C. Feng
    SARI-CAS, Pudong, Shanghai, People’s Republic of China
 
  FEL self-seeding has been demonstrated a great advantage for the generation of a fully coherent and high brightness X-ray pulse experimentally. Generally, transmission monochromators with single crystal are adopted worldwide, such as LCLS, PAL-XFEL and European-XFEL. Recently, the self-seeding scheme based on a reflection monochromator with a double-crystal is proposed and demonstrated at SACLA successfully. In view of several potential advantages of the reflection type, here we give the proposal of the reflection monochromator based self-seeding and enable the application on the SHINE project. This manuscript is mainly focus on monochromator schemes at SHINE, instead of FEL simulations. We will present considerable schemes based on the specific undulator line.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB047  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPRB072 Compact APPLE X for Future SXL FEL and 3 GeV Ring at MAX IV Laboratory undulator, polarization, vacuum, FEL 1833
 
  • H. Tarawneh, P. N’gotta, L.K. Roslund, A. Thiel, K. Åhnberg
    MAX IV Laboratory, Lund University, Lund, Sweden
 
  An overview of the design of compact elliptically polarizing undulator with small round magnetic gap to provide full polarization control of synchrotron radiation in a more cost effective manner and consuming less built in space than the state of the art devices. This type of undulator is meant as source for the potential future Soft X-ray (SXL) FEL beamline using the linear accelerator at MAX IV. In addition, it offers new capabilities for future beamlines at the 3 GeV ring to use full polarization control to photon energies using the fundamental harmonic which are not attainable with today’s technology of the out-of-vacuum insertion devices at 3 GeV beam energy.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB072  
About • paper received ※ 30 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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TUPRB081 Beam Motion and Photon Flux Dips during Injection at the Taiwan Photon Source injection, kicker, betatron, vacuum 1848
 
  • C.H. Huang, H.-P. Chang, C.H. Chen, Y.-S. Cheng, P.C. Chiu, C.-S. Fann, K.T. Hsu, K.H. Hu, C.Y. Liao, Y.-C. Liu, C.Y. Wu
    NSRRC, Hsinchu, Taiwan
 
  The Taiwan photon source (TPS) is a 3 GeV synchrotron light source now in routine operation at the NSRRC. At the beginning of beam commissioning, significant photon flux dips could be observed at injection due to a blow-up of the beam size. To eliminate this transient effect, all four kickers were rematched. The leakage field was shielded and the induced current loops at vacuum chambers in the injection area were also eliminated. These efforts reduced the horizontal betatron oscillations and orbit distortions to around one-tenth. In order to decrease the recovery time of photon dips during injection, the operational chromaticity was reduced to improve incoherent effects. After all those improvements, the photon flux dips during injection dropped to 30 % and the recovery time to less than 1 msec.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB081  
About • paper received ※ 17 April 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPRB088 Generation of High Peak Power Hard X-Rays at LCLS-II with Double Bunch Self-seeding FEL, electron, laser, undulator 1863
 
  • A. Halavanau, F.-J. Decker, Y. Ding, C. Emma, Z. Huang, J. Krzywiński, A.A. Lutman, G. Marcus, C. Pellegrini, D. Zhu
    SLAC, Menlo Park, California, USA
 
  Funding: This work was supported by the U.S. Department of Energy Contract No. DE-AC02-76SF00515.
We propose to use existing LCLS copper S-band linac double bunch infrastructure to significantly improve LCLS-II hard X-ray performance. In our setup, we use the first bunch to generate a strong seeding X-ray signal, and the second bunch, initially traveling off-axis, to interact with the seed in the amplifier undulator and generate a near TW, 15 fs duration X-ray pulse in the 4 to 8 keV photon energy range. We investigate, via numerical simulations, the required transverse beam dynamics and the four crystals X-ray monochromator to be added to the existing LCLS-II beamline and discuss the final properties of the hard X-ray pulses and their potential application in high intensity, high-field physics experiments, including QED above the Schwinger critical field.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB088  
About • paper received ※ 13 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPRB089 Undulator Radiation Generated by a Single Electron electron, undulator, experiment, radiation 1867
 
  • A. Halavanau, Z. Huang, C. Pellegrini, T.O. Raubenheimer
    SLAC, Menlo Park, California, USA
  • I. Lobach
    University of Chicago, Chicago, Illinois, USA
  • S. Nagaitsev
    Fermilab, Batavia, Illinois, USA
  • D. Seipt
    HZDR, Dresden, Germany
 
  Funding: This work was supported by the U.S. Department of Energy Contract No. DE-AC02-76SF00515.
The facilities providing single electron beams are currently being commissioned at Fermilab and will be at SLAC. Recently, Fermilab’s IOTA ring routinely demonstrated circulation of a single electron at 100 MeV beam energy. Alternatively, SLAC is working on constructing LCLS-II an X-ray FEL driven by a 4 GeV SRF linac. A parasitic beamline, S30XL, is planned that will extract 4 GeV dark current from between the primary LCLS-II electron bunches. The dark current will be delivered to End Station A and can work independently of LCLS-II experiments. The dark current will be bunched at a frequency of 46 MHz while extracted current varied from single electrons to 10’s of nA. In the present paper, we estimate the feasibility of propagating single electron beams through a conventional undulator, placed in the IOTA and S30XL beamlines. We explore the possible observable effects and experimental parameters range. In addition, we focus on potential applications of such beams in systems for high fidelity quantum measurements.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB089  
About • paper received ※ 13 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPRB090 Preliminary Considerations of Atomic Inner-Shell X-Ray Laser for Self-Seeding at LCLS-II FEL, simulation, radiation, experiment 1871
 
  • A. Halavanau, C. Pellegrini, J. Wu
    SLAC, Menlo Park, California, USA
  • A.I. Benediktovitch
    EuXFEL, Hamburg, Germany
  • N. Rohringer
    Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
 
  Funding: This work was supported by the U.S. Department of Energy Contract No. DE-AC02-76SF00515.
The atomic inner-shell X-ray lasing, induced by the irradiation of focused XFEL SASE pulses, was demonstrated in gases, liquid jets and solids. In this proceeding, we discuss the possible use of this concept in self-seeding scheme at LCLS-II. We provide a preliminary study of different lasing media and corresponding SASE XFEL parameters. For the case of noble gas inner-shell X-ray laser, we study the requirements for gas pressure and XFEL pulse focusing. Finally, we discuss possible designs of this system and its advantages in LCLS-II operations.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB090  
About • paper received ※ 13 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPRB094 New Superconducting Undulator Magnetic Measurement System for the Advanced Photon Source Upgrade GUI, undulator, vacuum, storage-ring 1881
 
  • M. Kasa, E.R. Anliker, Y. Ivanyushenkov, Y. Shiroyanagi
    ANL, Argonne, Illinois, USA
 
  Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
Magnetic measurements of existing superconducting undulators (SCUs) are performed under normal operating conditions after final assembly into the cryostat and before installation on the Advanced Photon Source (APS) storage ring. The SCU cryostat for the APS upgrade has been scaled in length from the current cryostat and will contain two SCUs. While some aspects of the current measurement system are desirable to retain, such as a room temperature measurement bore, scaling the current measurement techniques to the length required for the APS upgrade cryostat is not feasible. To address these challenges a unique system has been developed at the APS to allow measurements of the two SCU magnets in the long cryostat. The measurement system developed allows the magnets to be operated under normal operating conditions while maintaining the measurement equipment at room temperature and atmospheric pressure.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB094  
About • paper received ※ 14 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPRB095 Superconducting Undulators for the Advanced Photon Source Upgrade undulator, vacuum, electron, operation 1884
 
  • M. Kasa, E.R. Anliker, J.D. Fuerst, Q.B. Hasse, Y. Ivanyushenkov, I. Kesgin, Y. Shiroyanagi, E. Trakhtenberg
    ANL, Argonne, Illinois, USA
 
  Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
The magnetic devices group at the Advanced Photon Source (APS) is in the process of designing and developing superconducting undulators (SCUs) for the APS upgrade. While similar in some aspects to previous SCU systems currently in operation at the existing APS, the new SCU systems will include two undulators installed in one cryostat which occupies an entire straight section of the storage ring. Straight sections containing planar undulators will either be configured as ’in-line’, where the two undulators behave as one source, or canted, where the two undulators are operated independently. Also under development is a superconducting arbitrary polarizing emitter (SCAPE) which can produce planar, elliptical, and helical undulator fields.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB095  
About • paper received ※ 14 May 2019       paper accepted ※ 18 May 2019       issue date ※ 21 June 2019  
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TUPTS026 Negative Electron Affinity GaAs Cathode Activation With CsKTe Thin Film cathode, electron, vacuum, gun 1986
 
  • M. Kuriki
    KEK, Ibaraki, Japan
  • K. Masaki
    HU/AdSM, Higashi-Hiroshima, Japan
 
  Funding: This work is partly supported by Japan-US Cooperative grant for scientific studies, Grant aid for scientific study by MEXT Japan (KAKENHI).
Negative Electron Affinity (NEA) GaAs cathode is an unique device which can generate a highly polarized electron beam with circularly polarized light. The NEA surface is conventionally made by Cs and \rm O/NF3 adsorption on the cleaned p-doped GaAs crystal, but the robustness of the cathode is very limited, so that the electron emission is easily lost by residual gas adsorption, ion back-bombardment, etc. To improve the cathode robustness, NEA activation with a stable thin-film on GaAs surface according to Hetero junction hypothesis has been proposed by the author. An experiment of the NEA activation with CsKTe thin film was carried out at Hiroshima University and a significant electron emission with 1.43 eV photon was observed which strongly suggested NEA activation. The cathode showed 16 to 20 times improvement of lifetime comparing to GaAs activated with Cs and O.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS026  
About • paper received ※ 26 April 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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TUPTS069 A Plasmonic Niobium Photocathode for SRF Gun Applications cathode, gun, laser, cavity 2079
 
  • F.E. Hannon
    JLab, Newport News, Virginia, USA
  • G. Andonian, L.H. Harris
    RadiaBeam, Marina del Rey, California, USA
 
  The typical quantum efficiency of niobium is of the order 10-4, whilst also requiring UV lasers for emission. This paper presents the results of a plasmonic niobium surface that operates with IR laser via multiphoton emission.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS069  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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TUPTS089 Observations of the Femtosecond Laser-Induced Emission From the Diamond Field Emitter Tips laser, electron, cathode, experiment 2130
 
  • E.I. Simakov, H.L. Andrews, R.L. Fleming, D. Kim, V.N. Pavlenko
    LANL, Los Alamos, New Mexico, USA
  • D.S. Black, K.J. Leedle
    Stanford University, Stanford, California, USA
 
  Funding: Los Alamos National Laboratory LDRD Program
We present the results of experimental observation of emission from single diamond field emitter tips when triggered by an ultra-short laser pulse. Diamond field emitter array (DFEA) cathodes were originally proposed for applications that require large current densities. DFEAs represent periodic arrays of diamond pyramids with micron-size dimensions and tips with diameters of the order of tens of nanometers. DFEAs are known to produce significant currents in field emission regime under direct current (DC) fields and in radio-frequency (RF) guns. It has been proposed that single diamond tip emitters can be employed for production of small tightly focused electron beams for dielectric laser accelerators (DLAs) that accelerate particles using the energy of light produced by infrared lasers. To generate short electron bunches required by DLAs diamond pyramids may be triggered with a laser. We have recently observed emission produced by a single diamond pyramid when triggered by a laser at different wavelengths from 256 nm to 2020 nm. We have conducted studies with the goal to understand mechanism of the emission. We clearly observed the change in emission mechanism when the wavelength changed from 256 nm to 512 nm. We believe that while the emission at 256 nm is a clear photoemission, the emission at longer wavelengths is likely the field emission caused by intense electric fields of the laser.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS089  
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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WEPMP009 Renovation of Off-Axis Beam Injection Scheme for Next-Generation Photon Sources septum, injection, vacuum, kicker 2318
 
  • S. Takano, K. Fukami, C. Kondo, M. Masaki, M. Oishi, M. Shoji, K. Tamura, T. Taniuchi, T. Watanabe, K. Yanagida
    JASRI, Hyogo, Japan
  • H. Akikawa, K. Sato
    Nihon Koshuha Co. Ltd, Yokohama, Japan
  • K. Fukami, T. Hara, T. Inagaki, C. Kondo, M. Oishi, S. Takano, H. Tanaka, T. Watanabe
    RIKEN SPring-8 Center, Hyogo, Japan
  • K. Hamato, J. Kataoka, K. Kusano, K. Ogata, Y. Saito
    TOKIN, Sendai, Miyagi, Japan
 
  Funding: Work supported by Ministry of education, culture, sports, science and technology JAPAN (MEXT).
Photon sources are looking for performance upgrades by pursuing higher photon brilliance and coherence these years. The trend is pushing the lattice design to lower the beam emittance, which naturally results in the narrower dynamic aperture. One bottleneck in the upgrades is a beam injection system capable of accumulating required beam intensity and keeping top-up operations with such narrow apertures. Beam injection with a nonlinear kicker and transverse/longitudinal on-axis injections are now in the limelight. However, these techniques still need time to be put into practical use. We take an alternative approach for the SPring-8 upgrade, SPring-8-II, renovating the off-axis beam injection scheme to address the following requirements for the coming diffraction-limited storage rings (DLSRs): minimizing of both injection beam amplitude and perturbation to stored beam, and topping-up functionality. This presentation will overview the renewed off-axis beam injection scheme and report the development status of the following three key components: 1) permanent magnet based DC septum magnet, 2) in-vacuum pulse septum magnet, and 3) twin kickers driven by a single solid state pulser.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP009  
About • paper received ※ 10 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPGW031 Measurement of Cherenkov Diffraction Radiation from a Short Electron Bunches at t-ACTS electron, radiation, experiment, detector 2536
 
  • S. Ninomiya, H. Hama, F. Hinode, K. Kanomata, S. Kashiwagi, S. Miura, N. M. Morita, T. Muto, I. Nagasawa, K. Nanbu, H. Saito, K. Takahashi, H. Yamada
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
 
  Cherenkov Diffraction Radiation (ChDR) can be considered as a tool of non-destructive beam diagnostics. It also has the feature that the photon flux of ChDR is proportional to the thickness of the dielectric used as the radiator and can be much larger than ordinary diffraction radiation. An experimental set-up for the measurement of coherent ChDR from short electron bunches of about 100 fs is being prepared at t-ACTS, Tohoku University. Results of a basic experimental study about coherent ChDR will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW031  
About • paper received ※ 16 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPGW062 Synchrotron Light Diagnostic Beamline Design for HEPS Storage Ring emittance, diagnostics, storage-ring, lattice 2619
 
  • D.C. Zhu, J.S. Cao, Y.F. Sui, J.H. Yue
    IHEP, Beijing, People’s Republic of China
 
  Funding: National Nature Science Foundation of China(11605213)
High Energy Photon Source (HEPS) is a 6 GeV ul-tralow-emittance storage ring light source to be built in Beijing, China. With a multiple-bend achromat lattice design, the storage ring is expected to achieve an ul-tralow emittance of 34 pm.rad. The horizontal and verti-cal beam sizes will be in the sub-10 μm level. Beam emit-tance will be measured with x-ray diagnostic beamline at a low dispersion bending magnet source point. A visible light beamline will be designed to measure the bunch length and purity. In this paper, we will introduce the x-ray beamline, which combine with different techniques to resolve beam sizes and emittance.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW062  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPGW077 Recent Results using Incoherent Cherenkov Diffraction Radiation for Non-Invasive Beam Diagnostics radiation, experiment, diagnostics, beam-diagnostic 2654
 
  • M. Bergamaschi, R. Kieffer, T. Lefèvre, S. Mazzoni
    CERN, Geneva, Switzerland
  • A. Aryshev
    KEK, Ibaraki, Japan
  • P. Karataev
    Royal Holloway, University of London, Surrey, United Kingdom
  • P. Karataev, K. Lekomtsev
    JAI, Egham, Surrey, United Kingdom
  • A. Potylitsyn
    TPU, Tomsk, Russia
  • A. Schloegelhofer
    TU Vienna, Wien, Austria
 
  When a relativistic charged particle travels at a short distance from the surface of dielectric material Cherenkov Diffraction Radiation (ChDR) is produced inside the dielectric. Recent observation of incoherent ChDR in the visible spectrum has opened the possibility of using this radiation for non-invasive beam size and position measurements. An experimental test to study this technique for highly directional beam position measurement has been initiated on the CLEAR facility at CERN, whilst another experimental investigation is underway at the Accelerator Test Facility 2 (ATF2) at KEK, Japan, to measure the resolution limit of ChDR for beam imaging diagnostics. This contribution presents the latest experimental results from both of these test facilities.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW077  
About • paper received ※ 01 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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WEPGW087 Control System Studio to Monitor Front End and Beamlines Status as well as Light Source Stability electron, status, operation, controls 2687
 
  • W.Y. Lin, B.Y. Chen, C.S. Huang, C.H. Kuo, T.Y. Lee
    NSRRC, Hsinchu, Taiwan
 
  The primary task during a shift change at the Taiwan Photon Source Accelerator Operations team is to know the exact status of the machine, so that problems can be discovered immediately and solved when the machine behaves abnormal. To provide a stable beam during top-up operation, it is necessary to monitor closely the stability of the light source, of front end areas and beamlines. Should any abnormality occur, the operator would initiate initial troubleshooting and adjustments, inform users and sub-system staff members and perform subsequent first anal-yses and system optimizations. In this article, we describe how to sort through the nec-essary information with the Control System Studio (CSS) design page. There are currently seven beamlines in operation at the Taiwan Photon Source (05, 09, 21, 23, 25, 41, 45) and more new beamlines will be added in the future. Com-pared with other tools, CSS is intuitive and easy to revise. No matter weather adding new parameters or changing settings, the operation team can quickly get familiar with the machine status and perform an interface upgrade.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW087  
About • paper received ※ 27 April 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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WEPGW093 Commissioning of the Prototype for a New Gas Curtain Beam Profile Monitor Using Beam Induced Fluorescence for HL-LHC electron, gun, background, experiment 2709
 
  • A. Salehilashkajani, C.P. Welsch, H.D. Zhang
    The University of Liverpool, Liverpool, United Kingdom
  • M. Ady, N. Chritin, J. Glutting, O.R. Jones, R. Kersevan, T. Marriott-Dodington, S. Mazzoni, A. Rossi, G. Schneider, R. Veness
    CERN, Geneva, Switzerland
  • P. Forck, S. Udrea
    GSI, Darmstadt, Germany
  • C.P. Welsch, H.D. Zhang
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  Funding: This work is supported by the HLLHCUK project and the STFC Cockcroft Institute core grant No. ST/G008248/1.
A new supersonic gas-jet curtain based beam profile monitor is under development for minimally invasive simultaneous transverse profile diagnostics of proton and electron beams, at pressures compatible with LHC. The monitor makes use of a thin gas-jet curtain angled at 45 degrees with respect to the charged particle beams. The fluorescence caused by the interaction between the curtain and the beam can then be detected using a dedicated imaging system to determine its transverse profile. This contribution details design features of the monitor, discusses the gas-jet curtain formation and presents various experimental tests, including profile measurements of an electron beam using nitrogen and neon curtains. The gas-jet density was estimated by correlating it with the number of photons detected by the camera. These measurements are then compared with results obtained using a movable pressure gauge. This monitor has been commissioned in collaboration with CERN, GSI and the University of Liverpool. It serves as a first prototype of a final design that will be placed in the LHC beam line to measure the profile of the proton beam.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW093  
About • paper received ※ 14 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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WEPGW096 Development of Supersonic Gas-Sheet-Based Beam Profile Monitors electron, background, radiation, monitoring 2717
 
  • H.D. Zhang, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • M. Ady, J. Glutting, O.R. Jones, T. Marriott-Dodington, S. Mazzoni, A. Rossi, G. Schneider, R. Veness
    CERN, Geneva, Switzerland
  • P. Forck, S. Udrea
    GSI, Darmstadt, Germany
  • A. Salehilashkajani, C.P. Welsch, H.D. Zhang
    The University of Liverpool, Liverpool, United Kingdom
 
  Funding: HL-LHC project funded by STFC and CERN, and the STFC Cockcroft core grant No. ST/G008248/1.
Non-destructive beam profile monitoring is very desirable, essentially for any particle accelerator but particularly for high-energy and high-intensity machines. Supersonic gas jet-based monitors, detecting either the ionization or fluorescence of a gas sheet interacting with the primary beam to be characterized, allow for minimally invasive measurements. They can also be used over a wide energy range, from keV to TeV beams. This contribution gives an overview of the jet-based ionization and fluorescence beam profile monitors which have been developed, built and tested at the Cockcroft Institute. It discusses gas sheet generation, vacuum considerations, choice of gas species and detection methods.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW096  
About • paper received ※ 14 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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WEPGW120 Fluorescence-Based Imaging Diagnostic for High Average Power Deuteron Beam neutron, diagnostics, quadrupole, target 2777
 
  • R.A. Marsh, S.G. Anderson, D.J. Gibson, J. Hall, B. Rusnak
    LLNL, Livermore, California, USA
 
  Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Lawrence Livermore National Laboratory is developing an intense, high-brightness fast neutron source to create sub-millimeter-scale resolution neutron radiographs and imag-es. An intense source (1011 n/s/sr at 0 degrees) of fast neutrons (10 MeV) will be produced using a pulsed 7 MeV, 300μAmp average-current commercial deuteron accelerator producing a small (1.5 mm diameter) beam spot size to achieve high resolution. The high average power beam is a challenge for diagnostics, and a precise full power emittance measurement is critical to benchmark the system performance. A fluorescence-based beam profiling diagnostic has been selected, and this paper presents the design for the system including chamber layout, light yield calculations, and imaging system details.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW120  
About • paper received ※ 15 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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WEPRB116 X-ray Pinhole Camera for Emittance Measurements in Solaris Storage Ring emittance, storage-ring, radiation, diagnostics 3084
 
  • A. Kisiel, A.M. Marendziak, M. Ptaszkiewicz, A.I. Wawrzyniak
    Solaris National Synchrotron Radiation Centre, Jagiellonian University, Kraków, Poland
 
  X-ray pinhole camera is widely used system for the transverse beam profile measurement and emittance feedback. However this method is predominantly applied to the middle and high energy storage rings. At Solaris storage ring with the nominal energy of 1.5 GeV, the design of the beamline was modified to provide sufficient X-ray photon flux for proper imaging. The successful installation and commissioning of the X-ray pinhole beamline allows now to measure the emittance and helps in proper 3rd harmonic cavities tuning against the coupled bunch mode instabilities. The paper describes the design details, simulations and measurement results obtained during the beamline operation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB116  
About • paper received ※ 14 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPTS104 Synchrotron Radiation Reflections in the CLIC Beam Delivery System detector, collider, synchrotron, radiation 3363
 
  • D. Arominski, A. Latina, A. Sailer, D. Schulte
    CERN, Meyrin, Switzerland
 
  Synchrotron radiation (SR) reflection is an important issue for future linear colliders. High fluxes of the SR might impact the performance of the detector, through irradiation of the forward luminosity and beam quality calorimeters or of the innermost layers of the vertex detector. The photon reflections depend on the beam pipe apertures’ size, their shape, and materials used with various surface roughness. In this work, we present a study of SR including reflection for the 380 GeV and 3 TeV beam parameters and optics of the Compact Linear Collider’s Final Focus System. The simulations of the SR reflections using the Synrad+ software are presented and the impact on the detector is discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS104  
About • paper received ※ 29 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THYPLM1 Development of the Vertically Polarizing Hard X-Ray Undulator Segments for the Linear Coherent Light Source Upgrade (LCLS-II) Project undulator, operation, free-electron-laser, electron 3408
 
  • M. Leitner, D. Arbelaez, J.N. Corlett, A.J. DeMello, L. Garcia Fajardo, D. Leitner, S. Marks, K.A. McCombs, T. Miller, D.V. Munson, J. Niu, K.L. Ray, D.A. Sadlier, D. Schlueter, E.J. Wallén
    LBNL, Berkeley, California, USA
  • H. Bassan, D.E. Bruch, D.S. Martinez-Galarce, H.-D. Nuhn, M. Rowen, Z.R. Wolf
    SLAC, Menlo Park, California, USA
  • C.W. Chen
    NSRRC, Hsinchu, Taiwan
 
  Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Linear Coherent Light Source II (LCLS-II) is a free electron laser facility currently in its final construction stage at Stanford Linear Accelerator Center. The project includes two variable-gap, hybrid-permanent-magnet undulator lines: A soft x-ray undulator line with 21 undulator segments optimized for a photon energy range from 0.2 keV to 1.3 keV and a hard x-ray undulator line with 32 undulator segments designed for a photon energy range from 1.0 keV to 25.0 keV. This paper focuses on the design, development, and performance of the hard x-ray undulator line which utilizes uniquely-developed, vertically-polarizing undulators. To fully compensate the magnetic force throughout the entire gap range these devices incorporate non-linear spring systems which permit the construction of relatively compact undulators. However, significant magnetic field repeatability challenges have been encountered during prototyping of this novel design. The paper describes the innovative design improvements that were implemented which lead to reaching the LCLS-II required performance. These final design solutions can also be advantageous improving the operation of any future undulator design.
 
slides icon Slides THYPLM1 [28.498 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THYPLM1  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THYYPLS3 A Remote-Controlled Robot-Car in the TPS Tunnel controls, radiation, operation, laser 3435
 
  • T.Y. Lee, B.Y. Chen, T.W. Hsu, B.Y. Huang, C.H. Kuo, W.Y. Lin
    NSRRC, Hsinchu, Taiwan
 
  A remote-controlled robot-car named ’PhotonBot’ was put into the TPS accelerator tunnel and is equipped with a 360 degrees LiDAR for SLAM and navigation, two cameras for perception and first-person view, and a thermal imaging system. The robot can be remotely controlled and can send data to a remote PC through Wi-Fi. With SLAM, it can go more freely without being restricted to a designated path. In order to ensure it can work continuously, there is a wireless charging station in case of a low battery.  
slides icon Slides THYYPLS3 [18.013 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THYYPLS3  
About • paper received ※ 09 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPMP008 Feasibility Study on Mo-99 Production Using Hybrid Method Based on High Power Electron Accelerator target, neutron, radiation, electron 3462
 
  • A. Taghibi Khotbeh-Sara, F. Rahmani
    KNTU, Tehran, Iran
  • F. Ghasemi
    NSTRI, Tehran, Iran
  • H. Khalafi
    AEOI, Tehran, Iran
  • M. Mohseni Kejani
    Shahid Beheshti University, Tehran, Iran
 
  In this study, the idea 99Mo production using hybrid method based on electron accelerator has been pre-sented. Two different main production channels of 100Mo(γ,n)99Mo and 98Mo(n,γ)99Mo can be used for 99Mo production in this system. By considering high power Linac (30 MeV, 1 mA in average beam current) and one-stage approach, the calculation of 100Mo(γ,n)99Mo reactions in the optimized 100Mo target in two different designs (strip and disc) has been simu-lated. It is predicted that about 61 and 53 Ci of 99Mo activity per 24-hour irradiation on the strip target and the disc plates can be achieved, respectively. The threshold energy of photoneutron at 100Mo is about 9 MeV, so a large part of bremsstrahlung photons cannot participate in photoneutron reaction. For feasibility study, new hybrid approach has been tested by 10 MeV Rhodotron. Due to the low threshold of photo-neutron in deuteron (about 2.2 MeV) and significant low energy photons in 100Mo, photoneutron flux is available. So, Molybdenum target in heavy water Tank increases the production yield of 99Mo using neutron absorption reaction in 98Mo. The total activity of 99Mo has been predicted about 0.23 Ci per 24 hours e-beam irradiation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP008  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THPMP049 Sequential Excitation Scheme for Laser Stripping of Hydrogen Ion Beams laser, electron, cavity, proton 3558
 
  • Y. Liu, A.V. Aleksandrov, S.M. Cousineau, T.V. Gorlov, A. Rakhman
    ORNL, Oak Ridge, Tennessee, USA
 
  Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE.
Resonant laser excitation of the electron in a hydrogen atom is essential to achieve high-efficiency laser stripping of hydrogen ion (H) beam. In the laser stripping experiments recently carried out at SNS, an ultra-violet (UV) laser was used to excite the electrons in 1-GeV hydrogen atoms from the n=1 state to the n=3 state. In this talk, we propose a sequential resonant excitation scheme by using two laser beams to excite electrons in a sequence of two steps: from the n=1 state to the n=2 state and from the n=2 state to any higher state. The advantages of the sequential resonant excitation scheme include (1) lower laser power requirement due to higher transition probability in the first excitation step and (2) possibility of shifting the stripping laser wavelength from UV regime to longer wavelengths. An application of the sequential resonant excitation scheme in combination with the double-resonance optical cavity technology to the laser stripping of 1.3-GeV H beam (envisioned in the SNS proton power upgrade project) will be described.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP049  
About • paper received ※ 14 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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THPGW014 Tolerance Studies and Limitations for Photonic Bandgap Fiber Accelerators laser, acceleration, simulation, electron 3605
 
  • L. Genovese, R.W. Aßmann, U. Dorda, M. Kellermeier, W. Kuropka, F. Lemery, F. Mayet
    DESY, Hamburg, Germany
  • W. Kuropka, F. Mayet
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
 
  Laser-driven hollow core photonic bandgap (PBG) fibers were proposed by Lin in 2001 as high-gradient accelerators. The central defect in the transversely periodic lattice supports an accelerating mode for synchronous acceleration in the ultra-relativistic regime. The optical frequencies in such dielectric laser accelerators motivate a sensitivity and tolerance study to overcome manufacturing imperfections. Finally we discuss the propagation characteristics of Lin-fibers and find that small-bandwidth (~ns) pulses would be needed for efficient acceleration over longer distances.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW014  
About • paper received ※ 16 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THPGW033 Numerical Study of Photonic-Crystal-Based Dielectric Accelerators GUI, acceleration, electron, impedance 3653
 
  • G. Torrisi, L. Celona, S. Gammino, D. Mascali, G. Sorbello
    INFN/LNS, Catania, Italy
  • C. De Angelis, A. Locatelli
    University of Brescia, Brescia, Italy
  • G.S. Mauro
    INFN/LNL, Legnaro (PD), Italy
  • G. Sorbello
    University of Catania, Catania, Italy
 
  All-dielectric electromagnetic band gap (EBG) waveguides structures promise significant improvement of accelerating gradient of laser-driven acceleration with the potential to miniaturize the accelerator itself. In this work we study photonic crystal structures designed for acceleration of relativistic electrons. We explore the performance of the all-dielectric EBG accelerating waveguide structures thanks to full wave electromagnetic simulations of couplers and accelerating waveguides. The characteristic interaction impedance, accelerating gradient and all the key parameters that are typically used to characterize linear accelerators are evaluated and used to compare the properties of the accelerating mode field distribution in different geometries.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW033  
About • paper received ※ 30 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPGW051 MCP Based Detectors of European XFEL FEL, detector, radiation, electron 3703
 
  • E. Syresin, O.I. Brovko, A.Yu. Grebentsov
    JINR, Dubna, Moscow Region, Russia
  • W. Freund, J. Grünert
    EuXFEL, Schenefeld, Germany
  • M.V. Yurkov
    DESY, Hamburg, Germany
 
  Radiation detectors based on microchannel plates (MCP) are used for measurements of the SASE process of the European XFEL. Detectors operate in a wide dynamic range from the level of spontaneous emission to the saturation level (between a few nJ and 25 mJ) and in a wide wavelength range from 0.05 nm to 0.4 nm for SASE1 and SASE2 and from 0.4 nm to 4.43 nm for SASE3. Photon pulse energies are measured by the MCPs with an anode and by a photodiode. The MCP imager measures the photon beam image with a phosphor screen. Three MCP detectors are installed, one behind each SASE undulator (SASE1, SASE2, and SASE3). Calibration and first experiments with the MCP detectors are under discussion.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW051  
About • paper received ※ 29 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPGW061 The K12 Beamline for the KLEVER Experiment target, detector, experiment, background 3726
 
  • M.W.U. Van Dijk, D. Banerjee, J. Bernhard, M. Brugger, N. Charitonidis, N. Doble, L. Gatignon, A. Gerbershagen, E. Montbarbon, B. Rae, M.S. Rosenthal, B. Veit
    CERN, Geneva, Switzerland
  • G. D’Alessandro
    JAI, Egham, Surrey, United Kingdom
  • M. Moulson
    INFN/LNF, Frascati, Italy
 
  The KLEVER experiment is proposed to run in the CERN ECN3 underground cavern from 2026 onward. The goal of the experiment is to measure BR(KL -> pi0 nu nu), which could yield information about potential new physics, by itself and in combination with the measurement of BR(K+ -> pi+ nu nu) of NA62. A full description will be given of the considerations in designing the new K12 beamline for KLEVER, as obtained from a purpose made simulation with FLUKA. The high intensities required by KLEVER, 2·1013 protons on target every 16.8s, with 5·1019 protons accumulated over 5~years, place stringent demands on adequate muon sweeping to minimize backgrounds in the detector. The target and primary dump need to be able to survive these demanding conditions, while respecting strict radiation protection criteria. A series of design choices will be shown to lead to a neutral beamline sufficiently capable of suppressing relevant backgrounds, such as photons generated by pi0 decays in the target, and Lambda -> npi0 decays, which mimic the signal decay.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW061  
About • paper received ※ 30 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPGW071 Genetic Optimisation of Beamline Design for DIAMOND synchrotron, framework, radiation, experiment 3753
 
  • F. Bakkali Taheri, M. Apollonio, R. Bartolini, B. Singh
    DLS, Oxfordshire, United Kingdom
  • R. Bartolini, J. Li
    JAI, Oxford, United Kingdom
  • R. Bartolini
    Oxford University, Physics Department, Oxford, Oxon, United Kingdom
 
  The problem of optimisation of beamline structures is studied, from the point of view of multi-objective genetic algorithms. While this approach has been successfully used in the exploration of potential particle accelerator lattices, it has never been applied to beamline design. In this paper, the Non-Dominated Sorting Genetic Algorithm II (NGSA II) is used to optimize a structure where photons are assumed to propagate through the optical elements according to the wavefront model as implemented in SRW. It is shown that appropriate objective functions can help to set up an interesting set of parameters, with competitive computational resources compared to the traditional approach. Examples illustrating this optimization method are shown in the context of DIAMOND.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW071  
About • paper received ※ 13 May 2019       paper accepted ※ 18 May 2019       issue date ※ 21 June 2019  
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THPRB033 Development Status of RF Reference Phase Stabilization System for SuperKEKB Injector LINAC linac, controls, feedback, distributed 3879
 
  • N. Liu, B. Du
    Sokendai - Hayama, Hayama, Japan
  • D.A. Arakawa, H. Katagiri, T. Kobayashi, T. Matsumoto, S. Michizono, T. Miura, F. Qiu, Y. Yano
    KEK, Ibaraki, Japan
  • T. Matsumoto, T. Miura, F. Qiu
    Sokendai, Ibaraki, Japan
 
  SuperKEKB injector linear accelerator (LINAC) has 600 m beam lines which consist of 8 sectors. The 2856 MHz RF reference signals are distributed to each sector with long phase stabilized optical fiber (PSOF). The RF reference phase stability requirement is estimated to be 0.2°(RMS) corresponding to 200 fs. The prototype of RF reference phase stabilization system with single mode optical circulator was implemented and demonstrated in the laboratory. The returned phase drift is compensated by a piezo-driven fiber stretcher. The transmitted phase through 120 m PSOF is stabilized to 41 fs (pk-pk), which fulfilled the requirement. This paper introduces the RF reference phase stabilization system and reports the preliminary feedback result.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB033  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THPRB062 New Orbit Correction Method Based on SVDC Algorithm for Ring Based Light Sources feedback, lattice, controls, simulation 3943
 
  • X.Y. Huang, J.S. Cao, Y.Y. Du, Y.H. Lu, H.Z. Ma, Y.F. Ma, Y.F. Sui, S.J. Wei, Y. Wei, Q. Ye, X.E. Zhang, D.C. Zhu
    IHEP, Beijing, People’s Republic of China
 
  Funding: Union Foundation of excellent post-doctoral of China
Orbit feedback system is essential for realizing the exceeding beam stability in modern ring based light sources. Most advanced light sources adopt the global correction scheme by using singular value decomposition (SVD) algorithm. In this paper, a new SVD with constraints method (SVDC) is proposed to correct the global and local orbit simultaneously. Numerical simulations are presented with the case of High Energy Light Source (HEPS) by comparing classic algorithms. The results show that SVDC is very effective for orbit correction and very easy to implement.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB062  
About • paper received ※ 09 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THPRB090 Laboratory Exhaust Gas Treatment Systems at TPS controls, synchrotron, status, experiment 4029
 
  • J.-C. Chang, W.S. Chan, Z.-D. Tsai
    NSRRC, Hsinchu, Taiwan
 
  There are three main laboratory exhaust gas treatment systems equipped at Taiwan Photon Source (TPS): acid/alkaline system for corrosive acids and alkalis, volatile solvents, and other hazardous chemicals; organic system for biological experiments; and general system for other gas. Gas is collected in hoods installed near the sources of contamination in laboratories. The contamination then is transported through duct to the gas treatment equipment installed outside of the TPS experimental hall.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB090  
About • paper received ※ 06 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPRB091 APPLICATION PROGRAMS FOR TPS BEAM TRIP ANALYSIS power-supply, kicker, electron, operation 4032
 
  • B.Y. Chen, T.W. Hsu, B.Y. Huang, C.S. Huang, C.H. Kuo, T.Y. Lee, W.Y. Lin
    NSRRC, Hsinchu, Taiwan
 
  For the Taiwan Photon Source (TPS), the orbit inter-lock system is one of the most important machine pro-tection systems. It is the fastest and the most preferred system to detect abnormalities to prevent possible dam-ages caused by magnet power supply failures or subsys-tems failures. In order to monitor electron orbit changes during a beam trip, we developed the ’orbit monitoring and recording tool’, the ’TBT BPM analysis tool’ and the ’magnet power supply recording and analysis tool’ to assist us in the failure analysis as will be discussed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB091  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THPRB095 A Simulation Framework for Photon-Particle Interactions for Laserwires and Further Applications laser, electron, scattering, simulation 4045
 
  • S. E. Alden, S.M. Gibson, L.J. Nevay
    JAI, Egham, Surrey, United Kingdom
 
  A model has been developed for simulating photon-particle interactions with Beam Delivery Simulation (BDSIM). BDSIM is a high energy physics program that utilises the Geant4, CLHEP, and ROOT libraries to seamlessly track particles through an accelerator. The photon-particle interactions introduce the capability for modelling a range of applications in accelerator physics. One such application is a laserwire which is a minimally invasive diagnostic technique to measure beam profiles and emittance. In this paper we describe the recent implementation of inverse Compton scattering and electron stripping of Hydrogen ions. This is demonstrated on an example beamline.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB095  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THPRB102 Monte Carlo Optimization of Fast Beam Loss Monitors for LCLS-II detector, target, electron, simulation 4066
 
  • M. Santana-Leitner, C.I. Clarke, A.S. Fisher, A.M. Harris, C. Hast, T.T. Liang
    SLAC, Menlo Park, California, USA
  • E. Griesmayer
    CIVIDEC Instrumentation, Wien, Austria
 
  Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515
Commissioning of the LCLS-II hard X-ray FEL is starting at SLAC National Accelerator Laboratory. This facility will ultimately accelerate electrons to 8 GeV, with beams of 375 kW at 1 MHz. At such high-powers, errant beams will need to be detected very fast -200 μs- to limit exposure and to protect beam-line and safety components. Currently, LCLS-I uses ion chambers both as Point Beam Loss Monitors (PBLM) by collimators, dumps, septa, etc., and also as Long Beam Loss Monitors (LBML) that provide detection coverage in extended areas where the accelerator enclosure is not sufficiently thick to shield full beam losses. But due to the finite ion mobility and related screening effects, ion chambers are not fast enough, and their response would not be linear at high charge rates. LCLS-II will use synthetic mono-crystalline diamond chips as PBLMs, as those offer nanosecond time resolution due to the high mobility of holes generated in the valence band by charged particles. LBLMs will be 200 m-long optical fibers, with photomultipliers to detect Cerenkov photons produced by charged particles in the fibers. Use of these technologies requires tests and models to correlate their response to different beam losses. Response functions for these detectors have been developed for the FLUKA Monte Carlo code. After benchmarking the models, these have been applied to place PBLMs at locations where signal is relatively insensitive to beam-strike uncertainties and sufficiently above electronic noise, while keeping lifetime to radiation-damage long. Also, topologies where found were one PBLM can protect several components, resulting in cost reductions. As for LBLMs, the existing model helps scale signals for different beam loss configurations as a function of the fiber position.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB102  
About • paper received ※ 14 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THPRB104 Improvements in Long-Term Orbit Stability at NSLS-II feedback, operation, controls, storage-ring 4070
 
  • Y. Hidaka, A. Caracappa, Y. Hu, B. Podobedov, R.M. Smith, Y. Tian, G.M. Wang
    BNL, Upton, Long Island, New York, USA
 
  Funding: The study is supported by U.S. DOE under Contract No. DE-SC0012704.
We report our latest efforts to further improve long-term orbit stability at NSLS-II, on top of what is already provided by fast orbit feedback (FOFB) system. A DC local bump generation program, only utilizing RF beam position monitors (BPM) and compatible with FOFB, was first implemented and deployed in operation successfully, allowing on-demand fine adjustments of beamline source positions and angles. Then we introduced a simple feedback version that performs these bump corrections automatically as needed to maintain the sources within in 1 um/urad for select beamlines. In addition, an RF frequency feedback was also implemented to improve stability for 3-pole wigglers and bending magnet users. As a parallel effort, X-ray BPMs were included in a local feedback system to stabilize photon beam motion for several ID beamlines. However, this feedback scheme is not transparent to FOFB, and suspected to be the source of occasional saturation of fast corrector strength. As an alternative solution, the local bump program and its feedback version has been recently upgraded to include bumps with X-ray BPMs and in operation since April 2019.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB104  
About • paper received ※ 19 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPTS056 New Undulator and Front End for XAIRA Beamline at ALBA undulator, vacuum, storage-ring, synchrotron 4231
 
  • J. Campmany, J. Marcos, V. Massana
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
 
  A new microfocus beamline for macromolecular crystallography, XAIRA, is being built at ALBA synchrotron light source. The light source for this new beamline is an in-vacuum undulator that can reach the spectrum range from 4 keV up to 20 keV. The in-vacuum undulator was terndered in 2018 and awarded to Kyma-RI consortium, and will be delivered to ALBA in November 2019. The Front End has been designed accordingly. It was tendered in 2018 and awarded to FMB. It will be delivered along second semester of 2019. In this paper we present the ID and FE designs.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS056  
About • paper received ※ 11 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPTS064 Sub-Picosecond X-Ray Streak Camera using High-Gradient RF Cavities electron, cathode, gun, simulation 4256
 
  • F. Toufexis, V.A. Dolgashev
    SLAC, Menlo Park, California, USA
 
  Funding: This project was funded by U.S. Department of Energy under Contract No. DE-AC02-76SF00515.
We are developing an ultrafast diagnostic system for X-ray beams from Synchrotron Light Sources and Free-Electron Lasers. In this system, the X-ray beam is focused on the photocathode of a high-gradient radio-frequency cavity that accelerates the photo-emitted electrons to a few MeV while preserving their time structure. The accelerated electron beam is streaked by radio-frequency deflectors and then imaged on a screen. This approach will allow orders of magnitude improvement in time resolution over traditional streak cameras and could potentially enable time-resolved diagnostics of sub-100 fs X-ray pulses. We present preliminary beam dynamics simulations of this system and discuss the implementation.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS064  
About • paper received ※ 11 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THPTS073 Radiation Damage to Undulator Electronics at an Electron Accelerator radiation, electron, electronics, neutron 4285
 
  • T.Y. Chung, C.-H. Chang, A.Y. Chen, Y.W. Chen, J.C. Huang, J.C. Jan
    NSRRC, Hsinchu, Taiwan
 
  Experience gained from commissioning and operation of three elliptical polarization undulators (EPU) at the TPS taught us that undulator driving systems can behave erratically following a beam dump or loss. In this work, we discuss possible harmful radiation sources in a storage ring and analyse the effect of lack of electronic component radiation resistance in the system. According to measurements of spatial radiation distribution at the TPS, we propose solutions and an improved design for Phase-II EPUs.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS073  
About • paper received ※ 19 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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THPTS093 Synchrotron Radiation Heating of the Helical Superconducting Undulator vacuum, synchrotron, radiation, synchrotron-radiation 4328
 
  • J.C. Dooling, R.J. Dejus, V. Sajaev
    ANL, Argonne, Illinois, USA
 
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02- 06CH11357.
A helical superconducting undulator (HSCU) was installed in the Advanced Photon Source (APS) Storage Ring (SR) during the January 2018 maintenance period. Shortly after the reintroduction of beam into the SR in late January, higher than expected heating was observed in the cryogenic cooling system. Steering the electron beam orbit in the upstream dipole provided reduction of the amount of synchrotron radiation reaching into the HSCU and allowed the device to properly cool and operate. Modeling the HSCU geometry with MARS shows the importance of Compton Scattering in transferring synchrotron photons with energies in the range of 10-100 keV through the vacuum chamber into the HSCU magnet pole and winding regions. Simulations carried out using MARS with EGS5 enabled indicate a rapid increase in transfer efficiency from the chamber wall to the HSCU with photon energy. Realistic spectral distributions of synchrotron photons are employed as input to MARS for several bending magnet field strengths.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS093  
About • paper received ※ 12 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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FRXXPLM2 Magnet Design for Siam Photon Source II quadrupole, sextupole, vacuum, multipole 4361
 
  • P. Sunwong, P. Klysubun, T. Phimsen, S. Prawanta, P. Sudmuang
    SLRI, Nakhon Ratchasima, Thailand
 
  Siam Photon Source II project has been approved and detailed technical design of the accelerator system is currently in progress. The Double Triple Bend Achromat (DTBA) lattice is implemented in the storage ring design for low emittance and more space for insertion devices. Magnets with moderate to high field requirements have been designed, including combined function magnet with the field gradient of 27.1 T/m, quadrupole magnets with the field gradient up to 60 T/m and multifunction sextupole magnets. This work presents the magnet requirement and specification, design concept, recent simulation results and analysis of the magnetic field quality. A plan for prototype development is also discussed.  
slides icon Slides FRXXPLM2 [1.475 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-FRXXPLM2  
About • paper received ※ 15 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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FRYPLM2 Lasers for Novel Accelerators laser, plasma, electron, operation 4385
 
  • L.A. Gizzi, P. Koester, L. Labate, G. Toci, M. Vannini
    INO-CNR, Pisa, Italy
  • F. Mathieu
    LULI, Palaiseau, France
  • Z. Mazzotta
    ARCNL, Amsterdam, The Netherlands
  • Z. Mazzotta
    Ecole Polytechnique, Palaiseau, France
 
  Significant progress has been made over the last decade in optical laser performance including repetition rate, average and peak power, and laser-system footprint making these systems attractive for many applications including novel accelerators. Most novel acceleration schemes require high-power lasers. The talk will present drive laser requirements for current novel accelerator schemes, industry plans to meet these requirements, and the future for high-power lasers.  
slides icon Slides FRYPLM2 [32.406 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-FRYPLM2  
About • paper received ※ 08 April 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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