Keyword: photon
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MOIYGD1 Progress in Developing an Accelerator on a Chip laser, electron, acceleration, focusing 16
 
  • R.J. England
    SLAC, Menlo Park, California, USA
  • R.L. Byer
    Stanford University, Stanford, California, USA
  • P. Hommelhoff
    University of Erlangen-Nuremberg, Erlangen, Germany
  
  Acceleration of particles in photonic structures fabricated using semiconductor manufacturing techniques and driven by ultrafast solid state lasers is a new and promising approach to developing future generations of compact particle accelerators. Substantial progress has been made in this area in recent years, fueled by a growing international collaboration of universities, national laboratories, and companies. Performance of these micro-accelerator devices is ultimately limited by laser-induced material breakdown limits, which can be substantially higher for optically driven dielectrics than for radio-frequency metallic cavities traditionally used in modern particle accelerators, allowing for 1 to 2 order of magnitude increase in achievable accelerating fields. The lasers required for this approach are commercially available with moderate (microJoule class) pulse energies and repetition rates in the MHz regime. We summarize progress to date and outline potential near-term applications and offshoot technologies.  
slides icon Slides MOIYGD1 [13.851 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOIYGD1  
About • Received ※ 03 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022
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MOOYSP1 Impact of Longitudinal Gradient Dipoles on Storage Ring Performance dipole, emittance, storage-ring, electron 30
 
  • F. Zimmermann, Y. Papaphilippou, A. Poyet
    CERN, Meyrin, Switzerland
  
  Funding: This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No 101004730 (iFAST).
Innovative new magnets with longitudinally varying dipole field are being produced for installation in a few modern light-source storage rings. We investigate some of the associated beam-dynamics issues, in particular the photon spectrum and quantum fluctuation associated with such magnets, and we study whether the resulting equilibrium emittance may deviate from the value expected in the long-magnet limit. 		 
slides icon Slides MOOYSP1 [2.364 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOOYSP1  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 17 June 2022
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MOPOPT013 Comparative Study of Broadband Room Temperature THz Detectors for High and Intermediate Frequency Response detector, experiment, electron, laser 257
 
  • R. Yadav, S. Preu
    IMP, TU Darmstadt, Darmstadt, Germany
  • A. Penirschke
    THM, Friedberg, Germany
  
  Funding: Scholarship from Hesse ministry of science and culture (HMWK), Germany.
Room temperature terahertz (THz) detectors based on Field effect transistors (FETs) and Zero-bias Schottky diodes (SD) are prominent members for the temporal-spatial characterization of pulses down to the picosecond scale generated at particle accelerators. Comparative study of in house developed THz detectors both at higher and intermediate frequency (IF) is carried out using table top THz systems and commercially available sources. In this paper, we present high frequency and intermediate frequency (IF) response of Gallium Arsenide (GaAs) FET and Zero-bias Schottky diode THz detectors. The IF results obtained are helpful for understanding and designing of optimized IF circuit with broader bandwidth. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT013  
About • Received ※ 19 May 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 25 June 2022
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MOPOPT017 Terahertz Sampling Rates with Photonic Time-Stretch for Electron Beam Diagnostics software, electron, laser, data-acquisition 263
 
  • O. Manzhura, E. Bründermann, M. Caselle, S.A. Chilingaryan, T. Dritschler, S. Funkner, A. Kopmann, A.-S. Müller, M.J. Nasse, G. Niehues, M.M. Patil, J.L. Steinmann
    KIT, Karlsruhe, Germany
  • S. Bielawski, E. Roussel, C. Szwaj
    PhLAM/CERCLA, Villeneuve d’Ascq Cedex, France
  • S. Bielawski, E. Roussel, C. Szwaj
    PhLAM/CERLA, Villeneuve d’Ascq, France
  
  Funding: Supported by the Helmholtz Program-Oriented Funding (PoF), research program Matter and Technologies (Detector Technology and System), ANR-DFG ULTRASYNC funding program, CEMPI LABEX and Wavetech CPER.
To understand the underlying complex beam diagnostic often large numbers of single-shot measurements must be acquired continuously over a long time with extremely high temporal resolution. Photonic time-stretch is a measurement method that is able to overcome speed limitations of con- ventional digitizers and enable continuous ultra-fast single- shot terahertz spectroscopy with refresh rates of trillions of consecutive frames. In this contribution, a novel ultra- fast data sampling system based on photonic time-stretch is presented and the performance is discussed. THERESA (TeraHErtz REadout SAmpling) is a data acquisition system based on the recent ZYNQ-RFSoC family. THERESA has been developed with an analog bandwidth up to 20 GHz and a sampling rate up to 90 GS/s. When combined with the photonic time-stretch setup, the system will be able to sample a THz signal with an unprecedented frame rate of 8 TS/s. Continuous acquisition for long observation times will open up new possibilities in the detection of rare events in accelerator physics. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT017  
About • Received ※ 08 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 05 July 2022
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MOPOPT045 Beam Loss Localisation with an Optical Beam Loss Monitor in the CLEAR Facility at CERN beam-losses, electron, detector, experiment 351
 
  • S. Benítez Berrocal, E. Effinger, J.C. Esteban Felipe, W. Farabolini, P. Korysko, A.T. Lernevall, B. Salvachúa
    CERN, Meyrin, Switzerland
  • M. Chen
    University of Huddersfield, Huddersfield, United Kingdom
  
  A prototype of a Beam Loss Monitor based on the detection of Cherenkov light in optical fibres is being developed to measure beam losses in the CERN Super Proton Synchrotron. Several testing campaigns have been planned to benchmark the simulations of the system and test the electronics in the CLEAR facility at CERN. During the first campaigns, the emission of Cherenkov light inside optical fibres and the photodetector characterisation were studied. Fibre-based Beam Loss monitors continuously monitor beam losses over long distances. The localisation of the beam loss could be calculated from the timing of the signals generated by the photosensors coupled at both ends of the optical fibre. The experimental results of an optical fibre Beam Loss Monitor installed in the CLEAR facility are reported in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT045  
About • Received ※ 03 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 24 June 2022
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MOPOPT048 Design of a Prototype Gas Jet Profile Monitor for Installation Into the Large Hadron Collider at CERN electron, proton, vacuum, experiment 363
 
  • R. Veness, M. Ady, C. Castro Sequeiro, T. Lefèvre, S. Mazzoni, I. Papazoglou, A. Rossi, G. Schneider, O. Sedláček, K. Sidorowski
    CERN, Meyrin, Switzerland
  • P. Forck, S. Udrea
    GSI, Darmstadt, Germany
  • N. Kumar, A. Salehilashkajani, O. Sedláček, C.P. Welsch, H.D. Zhang
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • N. Kumar, A. Salehilashkajani, O. Sedláček, O. Stringer, C.P. Welsch, H.D. Zhang
    The University of Liverpool, Liverpool, United Kingdom
  
  The Beam-Gas Curtain or BGC is the baseline instrument for monitoring the concentricity of the LHC proton beam with a hollow electron beam for the hollow e-lens (HEL) beam halo suppression device which is part of the High-Luminosity LHC upgrade. The proof-of-principles experiments of this gas-jet monitor have now been developed into a prototype instrument which has been built for integration into the LHC ring and is now under phased installation for operation in the upcoming LHC run. This paper describes the challenges overcome to produce a gas-jet fluorescence monitor for the ultra-high vacuum accelerator environment. It also presents preliminary results from the installation of the instrument at CERN.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT048  
About • Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 17 June 2022
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MOPOPT056 Commissioning of a Gas Jet Beam Profile Monitor for EBTS and LHC electron, simulation, vacuum, MMI 393
 
  • H.D. Zhang, N. Kumar, A. Salehilashkajani, O. Sedláček, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • M. Ady, T. Lefèvre, S. Mazzoni, I. Papazoglou, A. Rossi, G. Schneider, O. Sedláček, K. Sidorowski, R. Veness
    CERN, Meyrin, Switzerland
  • P. Forck, S. Udrea
    GSI, Darmstadt, Germany
  • N. Kumar, A. Salehilashkajani, O. Sedláček, O. Stringer, C.P. Welsch, H.D. Zhang
    The University of Liverpool, Liverpool, United Kingdom
  
  Funding: This work is supported by the HL-LHC-UK II project funded by STFC and CERN and the STFC Cockcroft core grant No. ST/G008248/1.
A gas jet beam profile monitor was designed for measuring the electron beam at the electron beam test stand (EBTS) for the Hollow electron lens (HEL) and the proton beam in the large hadron collider (LHC). It is partially installed in the LHC during the second long shutdown. The current monitor is tailored to the accelerator environment including vacuum, geometry, and magnetic field for both the EBTS and the LHC. It features a compact design, a higher gas jet density, and a wider curtain size for a better integration time and a larger detecting range. In this contribution, the commissioning of this monitor at the Cockcroft Institute will be discussed. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT056  
About • Received ※ 08 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022  
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MOPOMS005 Start-to-End Simulations of a THz-Driven ICS Source electron, linac, gun, simulation 631
 
  • M. Fakhari, Y.-K. Kan
    DESY, Hamburg, Germany
  • F.X. Kärtner
    The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany
  • F.X. Kärtner
    Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany
  • N.H. Matlis, M. Vahdani
    CFEL, Hamburg, Germany
  • M. Vahdani
    University of Hamburg, Hamburg, Germany
  
  We present start-to-end simulations for a fully THz-driven table-top X-ray source. A dielectric-loaded metallic cavity operating at its Higher Order Mode accelerates 1 PC photo emitted electron bunch up to 430 keV kinetic energy. The output beam of the gun is injected into a dielectric-loaded waveguide where phase velocity of the traveling wave is adjusted in such a way that electrons see an accelerating field all the way along the tube resulting to an 18.5-MeV output beam which is then transported to an inverse Compton scattering (ICS) stage. The injection phase of the electrons can be tuned to introduce a negative energy chirp to the electron bunch leading to a ballistic bunch compression after the linac. In addition, a set of permanent magnet quadrupoles is designed to focus the beam at the ICS interaction point where the electron beam scatters off a 250-mJ, 0.5ps, 1-µm laser beam and generates an X-ray beam with 2.6x107 photons per shot containing photon energies 2keV< Eph <8keV in a beam with 50 mrad half opening angle. The required terahertz waves to power the gun and linac are 550-ps pulses at 300 GHz containing 5 mJ and 23 mJ energies respectively with 1 kHz repetition rate.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS005  
About • Received ※ 08 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 25 June 2022  
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MOPOMS023 Start-to-End Beam-Dynamics Simulations of a Compact C-Band Electron Beam Source for High Spectral Brilliance Applications electron, simulation, FEL, laser 687
 
  • L. Faillace, M. Behtouei, B. Spataro, C. Vaccarezza
    LNF-INFN, Frascati, Italy
  • R.B. Agustsson, I.I. Gadjev, S.V. Kutsaev, A.Y. Murokh
    RadiaBeam, Santa Monica, California, USA
  • F. Bosco, M. Carillo, L. Giuliano, M. Migliorati, A. Mostacci, L. Palumbo
    Sapienza University of Rome, Rome, Italy
  • D.L. Bruhwiler
    RadiaSoft LLC, Boulder, Colorado, USA
  • O. Camacho, A. Fukasawa, N. Majernik, J.B. Rosenzweig, O. Williams
    UCLA, Los Angeles, USA
  • A. Giribono
    INFN/LNF, Frascati, Italy
  • S.G. Tantawi
    SLAC, Menlo Park, California, USA
  
  Funding: This work is partially supported by DARPA under the Contract No. HR001120C0072, by DOE Contract DE-SC0009914, DOE Contract DE-SC0020409, and by the National Science Foundation Grant No. PHY-1549132.
Proposals for new linear accelerator-based facilities are flourishing world-wide with the aim of high spectral brilliance radiation sources. Most of these accelerators are based on electron beams, with a variety of applications in industry, research and medicine such as colliders, free-electron lasers, wake-field accelerators, coherent THz and inverse Compton scattering X/’ sources as well as high-resolution diagnostics tools in biomedical science. In order to obtain high-quality electron beams in a small footprint, we present the optimization design of a C-band linear accelerator machine. Driven by a novel compact C-band hybrid photoinjector, it will yield ultra-short electron bunches of few 100’s pC directly from injection with ultra-low emittance, fraction of mm-mrad, and a few hundred fs length simultaneously, therefore satisfying full 6D emittance compensation. The normal-conducting linacs are based on a novel high-efficiency design with gradients up to 50 MV/m. The beam maximum energy can be easily adjusted in the mid-GeV’s range. In this paper, we discuss the start-to-end beam-dynamics simulations in details. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS023  
About • Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022
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MOPOMS025 Photocathode Performance Characterisation of Ultra-Thin MgO Films on Polycrystalline Copper cathode, electron, experiment, emittance 691
 
  • C. Benjamin, H.M. Churn, L.B. Jones, T.C.Q. Noakes
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • G.R. Bell, C. Benjamin, T.J. Rehaag
    University of Warwick, Coventry, United Kingdom
  • H.M. Churn, L.B. Jones, T.C.Q. Noakes
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: Department of Physics, The University of Warwick, Coventry, United Kingdom STFC ASTeC, Daresbury, Warrington, United Kingdom WA4 4AD
The performance expected from the next generation of electron accelerators is driving research into photocathode technology as this fundamentally limits the achievable beam quality. The performance characteristics of a photocathode are most notably; normalised emittance, brightness and energy spread*. Ultra–thin Oxide films on metal substrates have been shown to lower the work function (WF) of the surface, enhancing commonly utilised metal photocathodes, potentially improving lifetime and performance characteristics**. We present the characterisation of two MgO/Cu photocathodes grown at Daresbury. The surface properties such as; surface roughness, elemental composition and WF, have been studied using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). The photoemissive properties have been characterised with quantum efficiency (QE) measurements at 266 nm. Additionally, we measure the Transverse Energy Distribution Curves (TEDC) for these photocathodes under illumination at various wavelengths using ASTeC’s Transverse Energy Spread Spectrometer (TESS) and extract the Mean Transverse Energy (MTE)***.
*D.H. Dowell, et al, Nucl. Instr. and Meth A (2010), doi:10.1016/j.nima.2010.03.104
**V. Chang, et al, Phys. Rev. B (2018), doi.org/10.1103/PhysRevB.97.155436
***Proc. FEL ’13, TUPPS033, 290-293 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS025  
About • Received ※ 19 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 21 June 2022
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MOPOMS036 Simulations of Laser Field Emission from Nanostructures with Image Charge Trapping and Band Structure Transitions electron, laser, simulation, vacuum 717
 
  • B. Wang, G.E. Lawler, J.I. Mann, J.B. Rosenzweig
    UCLA, Los Angeles, California, USA
  • T. Arias, J.K. Nangoi
    Cornell University, Ithaca, New York, USA
  • S.S. Karkare
    Arizona State University, Tempe, USA
  
  Funding: National Science Foundation Grant No. PHY-1549132
Laser-induced field emission from nanostructures as a means to create high brightness electron beams has been a continually growing topic of study. Experiments using nanoblade emitters have achieved peak fields upwards of 40 GV/m, begging further investigation in this extreme regime. A recent paper has provided analytical reductions of the common semi-infinite Jellium system for pulsed incident lasers. We utilize these results as well as similar previous results to further understand the physics underlying electron rescattering-type emissions. We progress in numerically evaluating the analytical solution to attempt to more efficiently generate spectra for this system. Additionally, we use the full 1-D time-dependent Schrödinger equation with a Hartree potential and a dispersion-relation transition from material to vacuum to study the same system. We determine what importance the inclusion of the material band structure may have on emissions using this computationally challenging approach. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS036  
About • Received ※ 08 June 2022 — Revised ※ 21 June 2022 — Accepted ※ 27 June 2022 — Issue date ※ 01 July 2022
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MOOPLGD2 SPS-II: A 4th Generation Synchrotron Light Source in Southeast Asia storage-ring, synchrotron, vacuum, lattice 764
 
  • P. Klysubun, S. Boonsuya, T. Chanwattana, S. Jummunt, N. Juntong, A. Kwankasem, T. Phimsen, P. Photongkam, S. Prawanta, T. Pulampong, K. Sittisard, S. Srichan, P. Sudmuang, P. Sunwong, O. Utke
    SLRI, Nakhon Ratchasima, Thailand
  
  Upon its completion, Siam Photon Source II (SPS-II) will be the first 4th generation synchrotron light source in Southeast Asia. The 3.0 GeV, 327.5 m storage ring based on the Double-Triple Bend Achromat lattice will have the natural emittance of 0.97 nm·rad. The storage ring includes 14 long and 14 short straight sections for insertion devices and machine subsys-tems. The beam injection will be performed by a 150 MeV linear accelerator and a full-energy concentric booster synchrotron sharing the same tunnel with the storage ring. In the first phase, there will be 7 insertion devices and 7 associated beamlines with the end sta-tions for different techniques utilizing synchrotron radiation from 80 eV to 60 keV. High-energy and high-brightness radiation generated by the new light source will serve as one of the most powerful analytical tools in the region for advanced science and technology research.  
slides icon Slides MOOPLGD2 [4.168 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOOPLGD2  
About • Received ※ 12 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 05 July 2022  
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TUPOST046 Machine Learning Applied for the Calibration of the Hard X-Ray Single-Shot Spectrometer at the European XFEL FEL, controls, laser, operation 965
 
  • C. Grech, M.W. Guetg
    DESY, Hamburg, Germany
  • G. Geloni
    EuXFEL, Schenefeld, Germany
  
  Single-crystal monochromators are used in free electron lasers for hard x-ray self-seeding, selecting a very narrow spectral range of the original SASE signal for further amplification. When rotating the crystal around the roll and pitch axes, one can exploit several symmetric and asymmetric reflections as established by Bragg’s law. This work describes the implementation of a machine learning classifier to identify the crystal indices corresponding to a given reflection, and eventually calculate the difference between the photon energy as measured by a single-shot spectrometer and the actual one. The image processing techniques to extract the properties of the crystal reflection are described, as well as how this information is used to calibrate two spectrometer parameters.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST046  
About • Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 24 June 2022 — Issue date ※ 09 July 2022
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TUPOST049 Simulation Study for an Inverse Designed Narrowband THz Radiator for Ultrarelativistic Electrons radiation, simulation, electron, experiment 973
 
  • G. Yadav, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • T. Feurer
    Universität Bern, Institute of Applied Physics, Bern, Switzerland
  • U. Haeusler, A. Kirchner
    FAU, Erlangen, Germany
  • B. Hermann, R. Ischebeck
    PSI, Villigen PSI, Switzerland
  • P. Hommelhoff
    University of Erlangen-Nuremberg, Erlangen, Germany
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  THz radiation has many applications, including medical physics, pump-probe experiments, communications, and security systems. Dielectric grating structures can be used to generate cost-effective and beam synchronous THz radiation based on the Smith Purcell effect. We present a 3-D finite difference time domain (FDTD) simulation study for the THz radiation emitted from an inverse designed grating structure after a 3 GeV electron bunch traverses through it. Our farfield simulation results show a narrowband emission spectrum centred around 881 um, close to the designed value of 900 um. The grating structure was experimentally tested at the SwissFEL facility, and our simulated spectrum shows good agreement with the observed one.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST049  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 12 June 2022
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TUPOPT006 The New FLASH1 Beamline for the FLASH2020+ Project undulator, FEL, electron, dipole 1010
 
  • M. Vogt, J. Zemella
    DESY, Hamburg, Germany
  
  The 2nd stage of the FLASH2020+ project will be an upgrade of the FLASH1 beamline, downstream of the injector/linac section FLAH0 which is currently being upgraded. The currently existing beamline drives the original planar fixed gap SASE undulators from the TTF-2 setup, a THz undulator that uses the spent electron beam and deflects the e-beam into a dump beamline capable of safely dumping several thousand bunches per second. The updated beamline has been designed for EEHG seeding with 2 modulators, 3 chicanes, and a helical Apple-III undulator beamline as seeding radiator, followed by a transverse deflecting (S-band) structure for longitudinal diagnostics. The separation of the electron beam from the FEL beam will be moved upstream w.r.t. the old design to create more space for the photon diagnostics and will be achieved by a 5 deg double-bend-almost-achromat. To allow enable high power THz radiation output from a moderately compressed seeding beam, a post compressor will be installed. The capability of dumping the the long bunch trains safely may and will not be compromised by the design. This article describes the conceptional and some technical and details of the beamline.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT006  
About • Received ※ 07 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 23 June 2022  
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TUPOPT010 Virtual Commissioning of the European XFEL for Advanced User Experiments at Photon Energies Beyond 25 keV Using Low-Emittance Electron Beams FEL, electron, laser, free-electron-laser 1018
 
  • Y. Chen, F. Brinker, W. Decking, M. Scholz, L. Winkelmann, Z.H. Zhu
    DESY, Hamburg, Germany
  
  Funding: The authors acknowledge support from Deutsches Elektronen-Synchrotron DESY (Hamburg, Germany), a member of the Helmholtz Association HGF and European XFEL GmbH (Schenefeld, Germany).
Growing interests in ultra-hard X-rays are pushing forward the frontier of commissioning the European X-ray Free-Electron Laser (XFEL) for routine operation towards the sub-ångström regime, where a photon energy of 25 keV (0.5 ångström) is desired. Such X-rays allow for larger penetration depths and enable the investigation of materials in highly absorbing environments. Delivering the requested X-rays to user experiments is of crucial importance for the XFEL development. Unique capabilities of the European XFEL are formed by combining a high energy linac and the long variable-gap undulator systems for generating intense X-rays at 25 keV and pushing the limit even further to 30 keV. However, the FEL performance relies on achievable electron bunch qualities. Low-emittance electron bunch production, and the associated start-to-end modelling of beam physics thus becomes a prerequisite to dig into the XFEL potentials. Here, we present the obtained results from a virtual commissioning of the XFEL for the user experiments at 25 keV and beyond, including the optimized electron bunch qualities at variable accelerating cathode gradients and lasing studies under different conditions.
*Appl. Sci. 11(22), 10768 (2021)
**Phys. Rev. Accel. Beams 23, 044201(2020)
***NIM A 995, 11 165111 (2021) 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT010  
About • Received ※ 19 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 08 July 2022
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TUPOPT050 Investigation of Polarization Dependent Thomson Scattering in an Energy-Recovering Linear Accelerator on the Example of Mesa electron, scattering, HOM, polarization 1114
 
  • C.L. Lorey, A. Meseck
    KPH, Mainz, Germany
  
  Funding: GRK 2128 AccelencE funded by the DFG
At the Johannes Gutenberg University (JGU) in Mainz, a new accelerator is currently under construction in order to deliver electron beams of up to 155 MeV to two experiments. The Mainz Energy-recovering Superconducting Accelerator (MESA) will offer two modes of operation, one of which is an energy-recovering (ER) mode. As an ERL, MESA, with it’s high brightness electron beam, is a promising accelerator for supplying a Thomson back scattering based Gamma source. Furthermore, at MESA, the polarization of the electron beam can be set by the injector. The aim of this work is to provide a concept and comprehensive analysis of the merit and practical feasibility of a Thomson backscattering source at MESA under consideration of beam polarization and transversal effects. In this paper, an overview and results of our semi analytical approach to calculate various Thomson back scattering light source scenarios at MESA will be given. Furthermore we will discuss the benefits of using polarized electrons in combination with a polarized laser beam. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT050  
About • Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 26 June 2022
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TUPOPT052 Proposal for Non-Destructive Electron Beam Diagnostic with Laser-Compton Backscattering at the S-Dalinac electron, laser, scattering, linac 1121
 
  • M.G. Meier, M. Arnold, J. Enders, N. Pietralla
    TU Darmstadt, Darmstadt, Germany
  
  Funding: Work supported in part by the state of Hesse within the research cluster ELEMENTS (project ID 500/10.006) and the LOEWE research cluster Nuclear Photonics and by DFG through GRK 2128 "Accelence" and Inst163/308-1 FUGG.
To recover a large fraction of energy from the accelerator process in an energy-recovery linac, experiments, secondary-beam production, and beam diagnostics must be non-destructive and/or, hence, feature a low interaction probability with the very intense electron-beam. Laser-Compton backscattering can provide a quasi-monochromatic highly polarized X-ray to γ-ray beam without strongly affecting the electron beam due to the small recoil and the small Compton cross-section. Highest energies of the scattered photons are obtained for photon-scattering angles of \ang{180}, i. e., backscattering. A project at TU Darmstadt foresees to synchronize a highly repetitive high-power laser with the Superconducting DArmstadt electron LINear ACcelerator S\hbox{-}DALINAC, capable of running in energy recovery mode * to realize a laser-Compton backscattering source with photon beam energy up to §I{180}{\kilo\electronvolt}. The source will be first used as a diagnostic tool for determining and monitoring key electron-parameters, in particular energy and the energy spread at the S\hbox{-}DALINAC operation. Results are foreseen to be used for optimizing the design of laser-Compton backscattering sources at energy-recovery linacs.
*M. Arnold et al., Phys. Rev. Accel. Beams 23, 020101(2020)
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT052  
About • Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 24 June 2022
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TUPOMS005 SOLEIL Machine Status and Upgrade injection, lattice, synchrotron, vacuum 1397
 
  • L.S. Nadolski, G. Abeillé, Y.-M. Abiven, F. Bouvet, P. Brunelle, N. Béchu, M.-E. Couprie, X. Delétoille, S. Duigou, A. Gamelin, C. Herbeaux, N. Hubert, M. Labat, J.-F. Lamarre, V. Le Roux, A. Lestrade, A. Loulergue, O. Marcouillé, F. Marteau, A. Nadji, R. Nagaoka, M. Nouna, Y. Rahier, F. Ribeiro, G. Schaguene, K. Tavakoli, M.-A. Tordeux
    SOLEIL, Gif-sur-Yvette, France
  • S. Ducourtieux
    LNE, Trappes Cedex, France
  
  SOLEIL is both a 2.75 GeV third generation synchrotron light source and a research laboratory at the forefront of experimental techniques dedicated to matter analysis down to the atomic scale, as well as a service platform open to all scientific and industrial communities. We present the performance of the accelerators delivering extremely stable photon beams to 29 beamlines. We report on the commissioning of a superbend magnet replacing a standard 1.71T dipole with a 2.84 T narrow peak permanent magnet-based dipole. It required local modification of the lattice to compensate linear and nonlinear optics distortions introduced by the new magnet field. The latest measurements made with a Multipole Injection Kicker are also reported. Work on the NEG test bench and its dedicated front-end for a 10 mm inner diameter vacuum pipe and other major R&D areas are also addressed in the frame of the SOLEIL upgrade.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS005  
About • Received ※ 10 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 30 June 2022
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TUPOMS053 Start-to-End Simulations of the LCLS-II HE Free Electron Laser electron, FEL, undulator, simulation 1549
 
  • D.B. Cesar, G. Marcus, H.-D. Nuhn, T.O. Raubenheimer
    SLAC, Menlo Park, California, USA
  • J. Qiang
    LBNL, Berkeley, California, USA
  
  Funding: This work is supported in part by DOE Contract No. DE-AC02-76SF00515
In this proceeding we present start-to-end simulations of the LCLS-II-HE free electron laser. The HE project will extend the LCLS-II superconducting radio-frequency (SRF) linac from 4 GeV to 8 GeV in order to produce hard x-rays from the eponymous hard x-ray undulators (26 mm period). At the same time, soft x-ray performance is preserved (and extended into the tender regime) by using longer period undulators (56 mm period) than were originally built for LCLS-II (39 mm period). Here we use high-fidelity numerical particle simulations to study the performance of several SASE beamline configurations, and compare the resulting x-ray energy, power, duration, and transverse properties. Using the LCLS-II normal-conducting gun, we find that the x-ray pulse energy drops off rapidly above ~15 keV, while using the lower emittance beam from a proposed SRF gun, we improve the cutoff to ~20 keV. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS053  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 21 June 2022
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WEOYSP1 Experiments with Undulator Radiation, Emitted by a Single Electron synchrotron, electron, radiation, undulator 1628
 
  • I. Lobach
    ANL, Lemont, Illinois, USA
  • S. Nagaitsev, A.L. Romanov, A.V. Shemyakin, G. Stancari
    Fermilab, Batavia, Illinois, USA
  
  Funding: The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
We study a single electron, circulating in the Fermilab IOTA storage ring and interacting with an undulator through single and multi-photon emissions. The focus of this research is on single-photon and two-photon undulator emissions. We begin by using one Single Photon Avalanche Diode (SPAD) detector to detect the undulator radiation photons and search for possible deviations from the expected Poissonian photon statistics. Then, we go on to use a two-photon interferometer consisting of two SPAD detectors separated by a beam splitter. This allows to test if there is any correlation in the detected photon pairs. In addition, the photocount arrival times can be used to track the longitudinal motion of a single electron and to compare it with simulations. This allowed us to determine several dynamical parameters of the storage ring such as the rf cavity phase jitter and the dependence of the synchrotron motion period on amplitude. 		 
slides icon Slides WEOYSP1 [10.952 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOYSP1  
About • Received ※ 05 June 2022 — Revised ※ 25 June 2022 — Accepted ※ 03 July 2022 — Issue date ※ 27 June 2022
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WEPOST010 Controlling e+/e− Circular Collider Bunch Intensity by Laser Compton Scattering laser, electron, collider, scattering 1695
 
  • F. Zimmermann
    CERN, Meyrin, Switzerland
  • T.O. Raubenheimer
    SLAC, Menlo Park, California, USA
  
  Funding: This project receives funding from the European Union’s H2020 Framework Programme under grant agreement no. 951754 (FCCIS).
In the future circular electron-positron collider "FCC-ee", the intensity of colliding bunches must be tightly controlled, with a maximum charge imbalance between collision partner bunches of less than 3-5%. Laser Compton back scattering could be used to adjust and fine-tune the bunch intensity. We discuss a possible implementation and suitable laser parameters. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST010  
About • Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 03 July 2022
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WEPOST040 Comparing Methods of Recovering Gamma Energy Distributions from PEDRO Spectrometer Responses electron, positron, site, scattering 1784
 
  • M.H. Oruganti, B. Naranjo, J.B. Rosenzweig, M. Yadav
    UCLA, Los Angeles, California, USA
  
  To calculate the energy levels of the photons emitted from high-energy particle interactions, the new pair spectrometer (PEDRO) channels the photons through several Beryllium nuclear fields to produce electron-positron pairs through the nuclear field interaction. This project compared several methods of reconstruction and determined which best predicts original energy distributions based on simulated spectra. These methods included using Maximum Likelihood Estimation, Machine Learning, and directly analyzing a response matrix that modeled PEDRO’s response to any photon energy distribution. We report that performing the direct analysis, also known as QR decomposition, on a PEDRO-generated spectrum provides by far the most accurate calculation of the spectrum’s original energy distribution. These methods were tested against results from experimental cases, including Nonlinear Compton Scattering and Filamentation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST040  
About • Received ※ 15 June 2022 — Revised ※ 01 July 2022 — Accepted ※ 08 July 2022 — Issue date ※ 08 July 2022
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WEPOPT054 Target Studies for the FCC-ee Positron Source target, radiation, positron, electron 1979
 
  • F. Alharthi, I. Chaikovska, R. Chehab, S. Ogur, A. Ushakov, S. Wallon
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • L. Bandiera, A. Mazzolari, M. Romagnoni, A.I. Sytov
    INFN-Ferrara, Ferrara, Italy
  • J. Diefenbach, W. Lauth
    IKP, Mainz, Germany
  • O. Khomyshyn
    Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
  • D.M. Klekots
    National Taras Shevchenko University of Kyiv, The Faculty of Physics, Kyiv, Ukraine
  • V.V. Mytrochenko
    NSC/KIPT, Kharkov, Ukraine
  • P. Sievers, Y. Zhao
    CERN, Meyrin, Switzerland
  • M. Soldani
    Università degli Studi di Ferrara, Ferrara, Italy
  
  FCC-ee injector study foresees 3.5~nC electron and positron bunches with 200 Hz repetition and 2 bunches per linac pulse at 6~GeV extraction energy. Regarding the possible options of positron production, we retain both of the conventional amorphous target and the hybrid target options. The hybrid scheme uses an intense photon production by 6 GeV electrons impinging on a crystal oriented along a lattice axis. In such a way, it involves two targets: a crystal as a photon radiator and an amorphous target-converter. Therefore, to avoid early failure or damage of the target, the candidate materials for the crystal and conversion targets have started to be tested by using the intense electron beam at Mainzer Mikrotron in Germany by the end of 2021. By manipulating the beam intensity, focusing, and chopping, a Peak Energy Deposition Density in the tested targets could be achieved close to that generated by the electron/photon beam in the FCC-ee positron target. Radiation-damage studies of the crystal sample have been also performed allowing estimating the effect on the photon enhancement used in the hybrid positron source.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT054  
About • Received ※ 16 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 21 June 2022
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THPOST041 Construction and Manufacturing Process of Siam Photon Source II Storage Ring Girder Prototype controls, alignment, storage-ring, synchrotron 2537
 
  • S. Srichan, S. Klinkhieo, M. Phanak, S. Prabngulueam, P. Pruekthaisong, K. Sittisard
    SLRI, Nakhon Ratchasima, Thailand
  • O. Utke
    Synchrotron Light Research Institute (SLRI), Muang District, Thailand
  
  The Siam Photon Source II storage ring is designed with low emittance. This new machine requires a high performance support system and a precise alignment capability. In order to meet these requirements, we have planned for construction of a half-cell component prototype. In the end of 2021, we completed the first girder prototype. This report will describe construction and manufacturing process.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST041  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022
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THPOPT003 A First attempt at implementing TRIBs in BESSY III’s Design Lattice lattice, resonance, sextupole, quadrupole 2560
 
  • M. Arlandoo, P. Goslawski, M. Titze
    HZB, Berlin, Germany
  
  At HZB’s BESSY II and PTB’s Metrology Light Source (MLS), resonances and islands in transverse phase space are exploited in a special operation mode usually referred to as Transverse Resonance Island Buckets (TRIBs). This mode provides a second stable orbit well separated from the main orbit and one of its applications in photon science is the ultra-fast switching of the helicity of circularly polarized light pulses. In the context of the conceptual design study of BESSY III, it is under investigation how this special optics mode can be implemented in an MBA structure and how it will impact the photon source parameters. In this paper we present a preliminary attempt at implementing TRIBs in BESSY III’s design lattice, a multi-bend achromat, by breaking the symmetry of the lattice.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT003  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022
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THPOPT031 SUNDAE1: A Liquid Helium Vertical Test-Stand for 2m Long Superconducting Undulator Coils undulator, FEL, power-supply, experiment 2646
 
  • B. Marchetti, S. Abeghyan, J.E. Baader, S. Casalbuoni, M. Di Felice, U. Englisch, V. Grattoni, D. La Civita, M. Vannoni, M. Yakopov, P. Ziolkowski
    EuXFEL, Schenefeld, Germany
  • S. Barbanotti, H.-J. Eckoldt, A. Hauberg, K. Jensch, S. Lederer, L. Lilje, R. Ramalingam, T. Schnautz, R. Zimmermann
    DESY, Hamburg, Germany
  • A.W. Grau
    KIT, Karlsruhe, Germany
  
  Superconducting Undulators (SCUs) can produce higher photon flux and cover a wider photon energy range compared to permanent magnet undulators (PMUs) with the same vacuum gap and period length. To build the know-how to implement superconducting undulators for future upgrades of the European XFEL facility, two magnetic measurement test stands named SUNDAE 1 and 2 (Superconducting UNDulAtor Experiment) are being developed. SUNDAE1 will facilitate research and development on magnet design thanks to the possibility of training new SCU coils and characterizing their magnetic field. The experimental setup will allow the characterization of magnets up to 2m in length. These magnets will be immersed in a Helium bath at 2K or 4K temperature. In this article, we describe the experimental setup and highlight its expected performances.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT031  
About • Received ※ 03 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 17 June 2022
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THPOPT035 A Second Generation Light Source Aiming at High Power on the Giant Dipole Resonance insertion, dipole, cavity, resonance 2661
 
  • X. Buffat, L.L. Cuanillon, E.N. Kneubuehler
    CERN, Meyrin, Switzerland
  
  We propose an accelerator concept which could enable nuclear waste transmutation and energy amplification using a second generation light source rather than a high power proton beam. The main parameters of the ring and insertion devices are estimated, targeting a photon beam power of 1 GW with a spectrum that maximizes the potential for nuclear reactions via the Giant Dipole Resonance. The synergies with technologies developed for high energy physics, in particular within the Future Circular Collider study (FCC), are highlighted.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT035  
About • Received ※ 03 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 25 June 2022
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THPOPT048 Impact of IDs on the Diamond Storage Ring and Application to Diamond-II electron, storage-ring, feedback, emittance 2705
 
  • R.T. Fielder, B. Singh
    DLS, Oxfordshire, United Kingdom
  
  When investigating the effect of insertion devices (IDs) on storage ring operations, it is not possible to simulate all of the large number of gap, phase and field settings that are available. This can be of particular concern for transient effects in IDs that are moved frequently, or APPLE-II devices which may use many different polarisation states. We therefore present measurements of the impact of selected IDs on various parameters in the current Diamond storage ring including orbit distortion, tunes, chromaticity and emittance, and assess the expected impact when applied to the Diamond-II lattice.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT048  
About • Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 28 June 2022
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THPOPT052 The Status of the In-Vacuum-APPLE II Undulator IVUE32 at HZB / BESSY II undulator, vacuum, shielding, polarization 2716
 
  • J. Bahrdt, J. Bakos, S. Gaebel, S. Gottschlich, S. Grimmer, S. Knaack, C. Kuhn, F. Laube, A. Meseck, C. Rethfeldt, E.C.M. Rial, A. Rogosch-Opolka, M. Scheer, P.I. Volz
    HZB, Berlin, Germany
  
  At BESSY II, two new beamlines for RIXS and for X-Ray-microscopy demand a short period variably polarizing undulator. For this purpose, the first in-vacuum APPLE undulator worldwide is under construction. The parameters are as follows: period length=32mm, magnetic length=2500mm, minimum gap=7mm. The design incorporates a force compensation scheme as proposed by two of the authors at the SRI2018. All precision parts of the drive chain are located in air. New transverse slides for the transversal slit adjustment have been developed and tested. Optical micrometers measure the gap and shift positions, similar to the system of the CPMU17 at BESSY II. They provide the signals for motor feedback loops. A new UHV-compatible soldering technique, as developed with industry, relaxes fabrication tolerances of magnets and magnet holders and simplifies the magnet assembly. A 10-period prototype has been setup for lifetime tests of the new magnetic keeper design. The paper describes first results of the prototype and other key-components and summarizes the status of the full-scale undulator.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT052  
About • Received ※ 19 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 22 June 2022
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THPOPT058 Status and Powering Test Results of HTS Undulator Coils at 77 K for Compact FEL Designs undulator, wiggler, superconductivity, FEL 2726
 
  • S.C. Richter, A. Bernhard, A.-S. Müller
    KIT, Karlsruhe, Germany
  • A. Ballarino, T.H. Nes, S.C. Richter, D. Schoerling
    CERN, Meyrin, Switzerland
  
  Funding: This work has been supported by the Wolfgang Gentner Program of the German Federal Ministry of Education and Research (grant no. 05E18CHA).
The production of low emittance positron beams for future linear and circular lepton colliders, like CLIC or FCC-ee, requires high-field damping wigglers. Just as compact free-electron lasers (FELs) require high-field but as well short-period undulators to emit high energetic, coherent photons. Using high-temperature superconductors (HTS) in the form of coated ReBCO tape superconductors allows higher magnetic field amplitudes at 4 K and larger operating margins as compared to low-temperature superconductors, like Nb-Ti. This contribution discusses the development work on superconducting vertical racetrack (VR) undulator coils, wound from coated ReBCO tape superconductors. The presented VR coils were modularly designed with a period length of 13 mm. Powering tests in liquid nitrogen of multiple vertical racetrack coils were performed at CERN. The results from the measurements are presented for three VR coils and compared with electromagnetic simulations. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT058  
About • Received ※ 17 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 21 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOPT061 European XFEL Undulators - Status and Plans undulator, FEL, electron, radiation 2737
 
  • S. Casalbuoni, S. Abeghyan, J.E. Baader, U. Englisch, V. Grattoni, S. Karabekyan, B. Marchetti, H. Sinn, F. Wolff-Fabris, M. Yakopov, P. Ziolkowski
    EuXFEL, Schenefeld, Germany
  
  European XFEL has three undulator lines based on permanent magnet technology: two for hard and one for soft X-rays. The planar undulators can be tuned to cover the acceptance in terms of photon beam energy of the respective photon beamlines: 3.6-25 keV (SASE1/2) and 0.25-3 keV (SASE3) by changing the electron energy range between 11.5 GeV and 17.5 GeV and/or the undulator gap. In order to obtain different polarization modes, as required by the soft X-ray beamlines, a helical afterburner consisting of four APPLE X undulators designed by PSI has been installed at the downstream end of the present SASE3 undulator system. The European XFEL plans to develop the technology of superconducting undulators, which is of strategic importance for the facility upgrade. In order to extend the energy range above 30 keV a superconducting undulator afterburner is foreseen to be installed at the end of SASE2. This contribution presents the current status and the planned upgrades of the undulator lines at European XFEL.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT061  
About • Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 04 July 2022
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THPOPT065 Operation of X-Ray Beam Position Monitors with Zero Bias Voltage at Alba Front Ends electron, operation, background, radiation 2747
 
  • J. Marcos, U. Iriso, V. Massana, R. Monge, D. Yépez
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  
  Blade-type X-ray Beam Position Monitors (XBPMs) are customarily operated with a negative bias voltage applied to the blades in order to prevent the transference of photoelectrons between the blades, and hence to maximize the signal at each blade and to avoid cross-talk. This was the selected approach at ALBA since the start of its operation for users in 2012. However, over the years the insulation provided by the ceramic pieces separating the blades from the support structure has degraded progressively, giving rise to an ever-increasing leakage current not related with the photon beam to be monitored. On 2020 the level of these leak currents had already become comparable to the photocurrents generated by the photon beam itself, making the readings from many of the XBPMs unreliable. Following the example from other facilities, we decided to remove the bias voltage from the blades and to test the performance of the XBPMs under these conditions, with such good results that we apply this method also for the new, non degraded, XBPMs. In this paper we present the approach used at ALBA to analyse XBPM data, and our experience operating them with zero bias voltage.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT065  
About • Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 29 June 2022
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THPOTK010 Development of a Short Period Superconducting Helical Undulator undulator, electron, FEL, simulation 2788
 
  • A.G. Hinton
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • J. Boehm, L. Cooper, B. Green, T. Hayler, P. Jeffery, C.P. Macwaters, B.J.S. Matthews
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  • S. Milward
    DLS, Oxfordshire, United Kingdom
  • B.J.A. Shepherd, N. Thompson
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  Superconducting technology provides the possibility to develop short period, small bore undulators that can generate much larger magnetic fields than alternative technologies. This may allow an XFEL with optimised superconducting undulators to cover a broader range of wavelengths than traditional undulators. At STFC, we have undertaken work to design and build a prototype superconducting helical undulator module with parameters suitable for use on a future XFEL facility. This work includes the design of an undulator with 13 mm period and 5 mm magnetic gap, as well as the supporting cryogenic and vacuum systems required for operation. We present here the updated design of the superconducting helical undulator that represents the results of prototyping work. Improved methods for manufacturing the undulator former and winding the superconducting wire have been developed. The measured mechanical tolerances and the impact on the field quality will be presented. The fields produced by prototype undulators will soon be measured using a Hall probe system.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK010  
About • Received ※ 06 June 2022 — Accepted ※ 10 June 2022 — Issue date ※ 17 June 2022  
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THPOTK036 Determination of Pumping and Dynamic Vacuum Properties of Conductive Quaternary Alloy of TiZrVAg Non-Evaporable Getter. vacuum, electron, experiment, site 2843
 
  • R. Valizadeh, A.N. Hannah, O.B. Malyshev
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • G.Y. Hsiung
    NSRRC, Hsinchu, Taiwan
  • J.M. O’Callaghan Castella
    Universitat Politécnica de Catalunya, Barcelona, Spain
  • M. Pont, N.D. Tagdulang
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  
  Non Evaporable Getter (NEG) coating has been employed extensively in the particle accelerator especially where the vacuum conductance of the vessel is severely restricted and ultra-high vacuum condition is required. NEG coating will significantly reduce the outgassing rate and provides active pumping surface for H2, CO and CO2. In addition, it has been proven that NEG coated surfaces have a very low secondary electron yield, as well as low photon and electron stimulated desorption yields. However, the existing NEG film increases the RF surface resistance of the beam pipe. In order to increase NEG coating conductivity, at ASTeC, in the past several years, the alternative NEG com-position have been studied by adding more conductive element such as Cu, Au, Al and Ag. In this study, we report on the photon stimulated desorption, activation temperature and surface resistance from room temperature to cryogenic temperature for a new NEG quaternary alloy of TiVZrAg as function of the film composition.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK036  
About • Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 01 July 2022
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THPOTK037 Measurement of the Photon Stimulated Desorption for Various Vacuum Tubes at a Beam Line of TLS experiment, vacuum, radiation, synchrotron 2847
 
  • G.Y. Hsiung, C.M. Cheng
    NSRRC, Hsinchu, Taiwan
  • R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  For most light sources, the synchrotron radiation (SR) hit on the beam ducts or absorbers results in higher pressure rise and the consequent higher radiation level through the commissioning stage. Various surface treatments, e.g. chemical cleaning, oil-free machining, NEG-coating, etc., for the beam ducts or absorbers have been developed worldwide for mitigating the yield of Photon Stimulated Desorption (PSD). A beam line, BL19B, of 1.5 GeV Taiwan Light Source (TLS) has been modified to measure the PSD-yield of the vacuum tubes. The white light of BL19B covers the critical length at 2.14 keV is suitable for generating higher yield of the photo-electrons (PEY) and the consequent PSD-yield to be measured can be resolved wide range of 10-2 ~ 10-7 molecules/photon. The PSD-outgas, measured by RGA, contains the typical H2, CO, CO2, hydrocarbons, and Kr from NEG-coating, alcohol from ethanol machined surface, in some cases. The effect of beam-cleaning reflects the PSD-molecules generated from the SR-irradiated surface. The comparison of the PSD for the various vacuum tubes will be described in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK037  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 08 July 2022
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THPOTK038 Electron Stimulated Desorption From Titanium Tube electron, vacuum, radiation, experiment 2850
 
  • O.B. Malyshev, R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  Titanium is one of material that used for production of accelerator vacuum chamber and components. In this paper we report the results of vacuum properties evaluation measurements of titanium vacuum chamber. The sample was produced from 40-mm inner diameter tube made of titanium and equipped with CF40 flanges at both ends. The electron stimulated desorption (ESD) was measured after 24-h bakeout to 80, 150, 180 and 250 oC. H2 and CO initial sticking probabilities were measured after bakeout before the ESD measurements. After ESD measurements, the initial H2 and CO sticking probabilities were measured again together with CO sorption capacity. These measurements provide the results for ESD as a function of electron dose baked to different temperatures and demonstrate the efficiency of electron stimulated activation of titanium vacuum chamber.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK038  
About • Received ※ 25 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
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THPOTK063 Open Source Software to Simulate Ti:Sapphire Amplifiers laser, simulation, optics, experiment 2925
 
  • D.L. Bruhwiler, D.T. Abell, B. Nash
    RadiaSoft LLC, Boulder, Colorado, USA
  • Q. Chen, C.G.R. Geddes, C. Tóth, J. van Tilborg
    LBNL, Berkeley, USA
  • N.B. Goldring
    STATE33 Inc., Portland, Oregon, USA
  
  Funding: This work is supported by the US Department of Energy, Office of High Energy Physics under Award Numbers DE-SC0020931 and DE-AC02-05CH11231.
The design of next-generation PW-scale fs laser systems, including scaling to kHz rates and development of new laser gain media for efficiency, will require parallel multiphysics simulations with realistic errors and nonlinear optimization. There is currently a lack of broadly available modeling software that self-consistently captures the required physics of gain, thermal loading and lensing, spectral shaping, and other effects required to quantitatively design such lasers.* We present initial work towards an integrated multiphysics capability for modeling pulse amplification in Ti:Sa lasers. All components of the software suite are open source. The Synchrotron Radiation Workshop (SRW)** is being used for physical optics, together with Python utilities. The simulations are being validated against experiments.
* R. Falcone et al., Brightest Light Initiative Workshop Report (2019).
** https://github.com/ochubar/srw 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK063  
About • Received ※ 14 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 16 June 2022
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THPOMS026 Monte Carlo Simulation of Electron Beam in Phantom Water for Radiotherapy Application electron, simulation, radiation, linac 3011
 
  • P. Apiwattanakul, C. Phueng-ngern, S. Rimjaem, J. Saisut
    Chiang Mai University, Chiang Mai, Thailand
  • P. Lithanatudom
    IST, Chiang Mai, Thailand
  • P. Nimmanpipug, S. Rimjaem, J. Saisut
    ThEP Center, Commission on Higher Education, Bangkok, Thailand
  
  Radiotherapy (RT) is an effective treatment that can control the growth of cancer cells. There is a hypothesis suggests that secondary electrons with an energy of a few eV produced from RT play an important role on cancer’s DNA strand break. In this study, the Monte Carlo simulation of electron beam irradiation in phantom water is performed to investigate the production of low-energy electrons. Electron beams produced from an radio-frequency linear accelerator (RF linac) are used in this study. The accelerator can generate the electron beam with adjustable energy of up to 4 MeV and adjustable repetition rate of up to 200 Hz. With these properties, the electron dose can be varied. We used ASTRA software to simulate the electron beam dynamics in the accelerator and GEANT4 toolkit for studying interactions of electrons in water. The energy of electrons decreases from MeV scale to keV-eV scale as they travel in the water. From simulations, the dose distribution and depth in phantom water were obtained for the electron dose of 1, 3, 5, 10, 25, and 50 Gy. Further study on effect of low-energy electron beam with these dose values on cancer DNAs will be performed with GEANT4-DNA simulation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS026  
About • Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 25 June 2022
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THPOMS033 Design and Optimisation of a Stationary Chest Tomosynthesis System with Multiple Flat Panel Field Emitter Arrays: Monte Carlo Simulations and Computer Aided Designs simulation, target, electron, diagnostics 3034
 
  • T.G. Primidis, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • T.G. Primidis, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • T.G. Primidis
    King’s College London, London, United Kingdom
  • V. Soloviev, S.G. Wells
    Adaptix Ltd, Oxford, United Kingdom
  
  Funding: Funded by the Accelerators for Security, Healthcare and Environment Centre for Doctoral Training of the United Kingdom Research and Innovation, Science and Technology Facilities Council, ST/R002142/1
Digital tomosynthesis (DT) allows 3D imaging by using a ~30° range of projections instead of a full circle as in computed tomography (CT). Patient doses can be ~10 times lower than CT and similar to 2D radiography but diagnostic ability is significantly better than 2D radiography and can approach that of CT. Moreover, cold-cathode field emission technology allows the integration of 10s of X-ray sources into source arrays that are smaller and lighter than conventional X-ray tubes. The distributed source positions avoid the need for source movements and Adaptix Ltd has demonstrated stationary 3D imaging with this technology in dentistry, orthopaedics, veterinary medicine and non-destructive testing. In this work we present Monte Carlo simulations of an upgrade to the Adaptix technology to specifications suited for chest DT and we show computer aided designs for a system with various populations of these source arrays. We conclude that stationary arrays of cold-cathode X-ray sources could replace movable X-ray tubes for 3D imaging and different arrangements of many such arrays could be used to tailor the X-ray fields to different patient size and diagnostic objective. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS033  
About • Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 22 June 2022
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THPOMS047 Design of Radiation Shielding for the PBP-CMU Electron Linac Laboratory radiation, shielding, electron, neutron 3073
 
  • P. Jaikaew, N. Khangrang
    Chiang Mai University, PBP Research Facility, Chiang Mai, Thailand
  • M. Jitvisate
    Suranaree University of Technology, Nakhon Ratchasima, Thailand
  • S. Rimjaem
    Chiang Mai University, Chiang Mai, Thailand
  • S. Rimjaem
    ThEP Center, Commission on Higher Education, Bangkok, Thailand
  
  The local radiation shielding is designed for the electron linear accelerator beam dump at the PBP-CMU Electron Linac Laboratory (PCELL) with the aim to control the annual ambient dose equivalent during the operation. The study of radiation generation and design of radiation shielding is conducted based on the Monte Carlo simulation toolkit GEANT4. The study results include an annual ambient dose equivalent map and design of local shielding for the first bam dump downstream the linac section. With this design, the leaking radiation outside the accelerator hall is completely blocked and the average annual ambient dose equivalent on the rooftop of the hall is within the IAEA safety limit for the supervised area. The shielding model will then be used as a guideline for the construction in the near future.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS047  
About • Received ※ 07 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 15 June 2022  
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THPOMS050 Design of Linac Based Neutron Source neutron, target, electron, linac 3084
 
  • N. Upadhyay, S. Chacko
    University of Mumbai, Mumbai, India
  • A.P. Deshpande, T.S. Dixit, R. Krishnan
    SAMEER, Mumbai, India
  
  Neutron sources are of great utility for various applications, especially in the fields of nuclear medicine, nuclear energy and imaging. At SAMEER, we have designed a linear electron accelerator based neutron source via photo-neutron generation. The accelerator is a 15 MeV linac with both photon and electron mode and is capable of delivering high beam current to achieve beam power of 1 to 2 kW. Efforts are in place to achieve further higher beam powers. 15 MeV electrons are incident on a bremsstrahlung target followed by a secondary target to achieve neutrons. To further optimize and enhance the neutron yield, backing material is provided. In this paper, we present the simulation of (e, g) and (g, n) processes using the Monte Carlo code FLUKA. The optimization of Tungsten as the convertor target whereas of the Beryllium as the neutron target is discussed in detail. We have explored various backing materials in order to optimize the total neutron yield as well as the thermal neutron yield. The simulation results have been considered for the finalisation of all material parameters for the set-up of this neutron source activity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS050  
About • Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 14 June 2022
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