TUPLH —  Tuesday Poster Session-Lake Huron   (03-Sep-19   16:30—18:00)
Paper Title Page
TUPLH01 Status of the Superconducting Undulator Program at the Advanced Photon Source -1
  • M. Kasa, E.R. Anliker, J.D. Fuerst, E. Gluskin, Q.B. Hasse, Y. Ivanyushenkov, W.G. Jansma, I. Kesginpresenter, Y. Shiroyanagi
    ANL, Lemont, Illinois, USA
  Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
Since 2013 there has been at least one superconducting undulator (SCU) in operation at the Advanced Photon Source (APS), currently there are two planar SCUs and one helical SCU. The combined operational experience of SCUs at the APS is more than 11 years and counting. Through all these years, APS SCUs operated with the predicted or better than predicted radiation performance and with 99% availability. With this demonstrated reliability and experimentally confirmed spectral performance, the APS upgrade project is planning on leveraging the advantages of SCU technology. The present planar SCUs are comprised of ~1.1-m-long magnets, each operated within a 2-m-long cryostat, while the planar SCUs for the upgrade will have two ~1.8-m-long magnets operating within a 5-m-long cryostat. Progress is also being made in other areas of SCU development with work on an arbitrary polarizing SCU, referred to as SCAPE, and a planar SCU wound with Nb3Sn superconductor. A Nb3Sn SCU is being designed with two 1.3-m-long magnets within a 5-m-long cryostat, and installation is planned for 2021. Also under development are the alignment and magnetic measurement systems for use with the 5-m-long cryostat.
TUPLH03 Double-Bend Achromat Beamline for Injection Into a High-Power Superconducting Electron Linac -1
  • C.H. Boulware, T.L. Grimm, R. Hipplepresenter
    Niowave, Inc., Lansing, Michigan, USA
  • S.M. Lund
    FRIB, East Lansing, Michigan, USA
  • V.S. Morozov
    JLab, Newport News, Virginia, USA
  To take advantage of the high duty cycle operation of superconducting electron linacs, commercial systems use thermionic cathode electron guns that fill every RF bucket with an electron bunch. In continuous operation, the exit energy is limited when compared to pulsed systems. Bunch length and energy spread at the exit of the gun are incompatible with low losses in the superconducting cavity. A solenoid double-bend achromatic beamline is in operation at Niowave which allows energy and bunch length filtering of the beam leaving the gun before injection into the superconducting cavity. This system uses two solenoids and two dipoles to produce a round beam, using the edge angles of the dipoles to balance the focusing effects in the two transverse planes. The design allows beam filtering on the symmetry plane where the dispersion is maximum. Additionally, the bend angle moves the electron gun off the high-energy beam axis, allowing multiple-pass operation of the superconducting booster. This contribution will discuss the beam optics design of the double-bend achromat along with the design of the magnets and beam chambers and the operational experience with the system.  
TUPLH04 Feasibility Study of Fast Polarization Switching Superconducting Undulator -1
  • I. Kesgin, Y. Ivanyushenkov, M. Kasa
    ANL, Lemont, Illinois, USA
  Funding: U.S. Department of Energy, Office of Science, under Contract No. DE-ACO2-O6CH11357.
Polarization switching x-ray probes coupled with high-flux provide a unique tool to unraveling the nature of electronic heterogeneity and drive discovery of novel phases of electronic matter. Superconducting Arbitrary Polarization Emitter (SCAPE) is a new concept for a universal undulator, which offers linear or circular polarization states in one device and is ideal for experiments that require polarization switching. Polarization switching relies on modulating the magnetic field in the undulator. This, however, inevitably incurs losses in superconductors, which need to be mitigated. In this study, feasibility of fast switching SCAPE has been investigated through fabricating and testing several short prototype magnets wound with different superconductors and new design concepts. The losses at different frequencies and field amplitudes are measured and details will be discussed.
EEX Based Correlated Energy Spread Control for XFELO  
  • J. Seok, M. Chung
    UNIST, Ulsan, Republic of Korea
  • M.E. Conde, G. Ha, J.G. Power
    ANL, Lemont, Illinois, USA
  X-ray Free Electron Laser Oscillator (XFELO) is considered next generation of linac-based x-ray source which can provide fully coherent, ultra-narrow and stable x-ray pulse. However, a long accelerating beamline and bunch compressor are increasing the correlated energy spread. XFELO is trapping x-rays in optical cavity with mirror which requires small energy spread and emittance due to spectral acceptance. The correlated energy spread can be suppressed using precise control of longitudinal phase space. When a beam is entering a double-emittance exchange (DEEX), transverse phase space manipulation in the middle of beamline is able to convert to longitudinal phase space at the end. The manipulated longitudinal phase space will compensate the increasing of correlated energy spread along the beamline. In this paper, we discuss concept of energy suppression using DEEX beamline and present progress on simulation results for XFELO.  
TUPLH07 High-Gradient Short Pulse Accelerating Structures -1
  • S.V. Kuzikov, S.P. Antipov, E. Gomez
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
  High gradients are necessary for lots of applications of electron accelerators. As the maximum gradient is limited by effects of RF breakdown, we present a development of an electron accelerating structure operating with a short multi-megawatt RF pulse. The structure exploits an idea to decrease the breakdown probability due to RF pulse length reduction. This concept requires to distribute RF power so that all accelerating cells are fed independently each other. This implies waveguide net system which allows to delay and to distribute properly RF radiation along the structure keeping synchronism of particles and waves. We have designed an X-band pi-mode structure including the RF design, optimization, and engineering. The structure will be tested as an RF power extractor at the Argonne Wakefield Accelerator Facility for two-beam acceleration experiments. In this regime we anticipate to obtain 10 ns, gigawatt power level RF pulses generated by train consisted of eight 25-50 nC relativistic bunches.  
poster icon Poster TUPLH07 [0.998 MB]  
TUPLH08 X-Ray and Charged Particle Detection by Detuning of a Microwave Resonator -1
  • S.P. Antipov, P.V. Avrakhov, E. Dosov, E. Gomez, S.V. Kuzikov
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • S. Stoupin
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • A.A. Vikharev
    IAP/RAS, Nizhny Novgorod, Russia
  Funding: DOE SBIR
Charged particle detection is important for beam alignment, beam loss and background control. In case of halo detection, traditional wire scanner measurement utilizing carbon or tungsten wires is limited by the damage threshold of these materials. In this paper we present an electrodeless method to measure halo with a diamond scraper. This measurement utilizes a microwave resonator placed around the diamond scraper which is sensitive to charged particle-induced conductivity. Due to this transient induced conductivity in the dielectric, a microwave coupling to the resonator changes. Diamond in this case is chosen as a radiation hard material with excellent thermal properties. The absence of electrodes makes the device robust under the beam. The same measurement can be done for x-ray flux monitoring which is important for measurement feedback and calibration at modern x-ray light sources. In this case x-rays passing through the diamond sensing element enable a photo-induced conductivity and that in turn detunes the cavity placed around the diamond. Diamond being a low-Z material allows for in-line x-ray flux measurement without significant beam attenuation.
TUPLH09 Thermal Effects on Bragg Diffraction of XFEL Optics -1
SUPLH05   use link to see paper's listing under its alternate paper code  
  • Z. Qu, J. Wu, G. Zhou
    SLAC, Menlo Park, California, USA
  • Y. Ma, Z. Qu
    UC Merced, Merced, California, USA
  • B. Yang
    Western Digital, Milpitas, California, USA
  Funding: The US Department of Energy (DOE) (DE-AC02-76SF00515); The US DOE Office of Science Early Career Research Program grant (FWP-2013-SLAC-100164).
Crystal optical devices are widely used in X-ray free electron laser (XFEL) systems, monochromators, beam splitters, high-reflectance backscattering mirrors, lenses, phase plates, diffraction gratings, and spectrometers. The absorption of X-ray in these optical devices can cause increase of temperature and consequent thermal deformation, which can dynamic change in optic output. In self-seeding XFEL, the thermal deformation and strain in monochromator could cause significant seed quality degradation: central energy shift, band broadening and reduction in seed power. To quantitatively estimate the impact of thermomechanical effects on seed quality, we conduct thermomechanical simulations combined with diffraction to evaluate the seed quality with residual temperature field in a pump-probe manner. With our results, we show that a critical repetition rate could be determined, once the criteria for deviation of the seed quality are selected. This tool shows great potential for the design of XFEL optics for stable operation.
Fabrication Progress of a Superconducting Helical Undulator with Superimposed Focusing Gradient for High Efficiency Tapered X-Ray FELs  
  • S.M. Lynam, R.B. Agustsson, I.I. Gadjev, A.Yu. Smirnov
    RadiaBeam, Santa Monica, California, USA
  • F.H. O’Shea
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  Funding: This work is supported by DOE grant no. DE-SC0017072, "Superconducting Helical Undulator with Superimposed Focusing Gradient for High Efficiency Tapered X-Ray FELs"
The Advanced Gradient Undulator (AGU) represents a potentially significant advancement in x-ray conversion efficiency for x-ray FELs. This increase in efficiency would have broad implications on the capabilities of x-ray light sources. To achieve this high conversion efficiency, the inner diameter of the undulator coil is a mere 7mm, even with the use of superconducting coils. To accommodate the beamline at the Advanced Photon Source this yields in a chamber with a wall thickness of 0.5mm fabricated from Aluminum. With a period of 2cm and a conductor position tolerance of <100 um over a length of >80cm at 4.2K, the engineering and fabrication challenges for the undulator alone are substantial. We will discuss these fabrication challenges and present solutions to meet the tolerances required for desired performance, and provide an update on current progress of the construction of a section of the AGU insertion device.
Mitigating a Large Energy Spread in the Laser Plasma Driven FEL Using FEL Beam Conditioning  
  • A.Y. Murokh, I.I. Gadjevpresenter
    RadiaBeam, Marina del Rey, California, USA
  The advances in laser-plasma acceleration (LPA) have enabled the production of quality electron beams for use in light-sources. In order to extend the usability of the LPA electron beam to drive a free-electron laser (FEL), the energy spread of the LPA beam must be reduced to the order of the FEL parameter. Here we propose a technique that circumvents the needed reduction in the electron beam’s energy spread and instead uses beam conditioning to introduce a correlation between the transverse position and energy spread of the electron beam. Such a correlation can be appropriately matched to a strong-focusing undulator FEL (such as VISA) in such a way that it induces an energy dependent transverse betatron amplitude. In this way, higher energy electrons that are off-resonance in the FEL can be made to participate in the lasing process and increase gain. In this paper, we will present preliminary numerical results, provide the theoretical basis for the effect, and discuss wavelength scaling for XFELs.  
Recent Developments in High Power High Brightness Double Bunch Self-Seeding at LCLS-II  
MOZBA4   use link to access more material from this paper's primary paper code  
  • A. Halavanau, F.-J. Decker, Y. Ding, C. Emma, Z. Huang, A.A. Lutman, G. Marcus, C. Pellegrini
    SLAC, Menlo Park, California, USA
  We discuss the power and spectral characteristics of an X-ray FEL, LCLS-II, operating in a double bunch self-seeding scheme (DBFEL). We show that it can reach very high power levels in the photon energy range of 4-8 keV. We discuss the system implementation on LCLS-II, including the design of a four-bounce crystal monochromator, and linac wakefields effects. Finally, we offer multiple applications of the DBFEL for high-field QED, AMO physics and single particle imaging.  
slides icon Slides TUPLH12 [3.166 MB]  
Study of Fluctuations in Undulator Radiation in the IOTA Ring at Fermilab  
SUPLH03   use link to access more material from this paper's primary paper code  
THYBA5   use link to access more material from this paper's primary paper code  
  • I. Lobach
    University of Chicago, Chicago, Illinois, USA
  • A. Halavanau, Z. Huang, V. Yakimenko
    SLAC, Menlo Park, California, USA
  • K. Kim
    ANL, Lemont, Illinois, USA
  • V.A. Lebedev, S. Nagaitsev, A.L. Romanov, G. Stancari
    Fermilab, Batavia, Illinois, USA
  • A.Y. Murokh
    RadiaBeam, Marina del Rey, California, USA
  • T.V. Shaftan
    BNL, Upton, 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. In this paper, we present a theoretical model for the experimental data from previous similar experiments and in our present experiment, we attempt to verify the model in an independent and a more systematic way. Moreover, in our experiment we consider the regime of very small fluctuation when the contribution from the photon shot noise is significant, whereas we believe it was negligible in the previous experiments. Accordingly, we present certain critical improvements in the experimental setup that let us measure such a small fluctuation.  
slides icon Slides TUPLH13 [8.044 MB]  
Strongly Tapered Helical Undulator System for TESSA-266  
MOZBA3   use link to access more material from this paper's primary paper code  
  • T.J. Campese, R.B. Agustsson, I.I. Gadjev, A.Y. Murokh
    RadiaBeam, Santa Monica, California, USA
  • W. Berg, A. Zholents
    ANL, Lemont, Illinois, USA
  • P.E. Denham, P. Musumeci, Y. Park
    UCLA, Los Angeles, USA
  Funding: DOE SBIR Award No. DE-SC0017102
RadiaBeam, in collaboration with UCLA and Argonne National Laboratory (ANL), is developing a strongly tapered helical undulator system for the Tapering Enhanced Stimulated Superradiant Amplification experiment at 266 nm (TESSA-266). The experiment will be carried out at the APS LEA facility at ANL and aims at the demonstration of very high energy conversion efficiency in the UV. The undulator system was designed by UCLA, engineered by RadiaBeam, and is presently in fabrication at RadiaBeam. The design is based on a permanent magnet Halbach scheme and includes a short 30 cm long buncher section and four 1 m long undulator sections. The undulator period is fixed at 32 mm and the magnetic field amplitude can be tapered by tuning the gap along the interaction. Each magnet can be individually adjusted by 1.03 mm, offering up to 25% magnetic field tunability with a minimum gap of 5.58 mm. A custom designed 316L stainless steel beampipe runs through the center with a clear aperture of 4.5 mm. This paper discusses the design and engineering of the undulator system, fabrication status, and plans for magnetic measurements, and tuning.
slides icon Slides TUPLH14 [9.166 MB]  
High-Power Superconducting Electron Linacs for Commercial Applications  
WEZBB4   use link to access more material from this paper's primary paper code  
  • C.H. Boulware, S. Baurac, J. Diemer, T.L. Grimm, A.B. Schnepp
    Niowave, Inc., Lansing, Michigan, USA
  Because of advances in niobium cavity resonator design and the continuing development of small helium cryocoolers, superconducting RF linacs have become a viable industrial technology for low-cost, high-power electron beams. These beams are being used to produce high-flux bremsstrahlung x-ray and neutron sources for commercial applications, particularly for the production of radioisotopes. This contribution will cover recent developments in commercial superconducting accelerator technology including thermionic cathode electron guns, superconducting cryomodules, helium cryocoolers, microwave sources, and target stations for the production of medical and industrial isotopes including molybdenum-99 and actinium-225. Machines at different stages of development span the energy range from 2-40 MeV and powers up to hundreds of kW. Connections will be made to high-power machines for high-throughput x-ray sterilization and accelerator-driven systems with electron beams.  
slides icon Slides TUPLH15 [6.860 MB]  
TUPLH17 Design Study of Low-Level RF Control System for CW Superconducting Electron Linear Accelerator in KAERI -1
  • S.H. Lee, J.Y. Lee
    Korea Atomic Energy Research Institute (KAERI), Daejeon, Republic of Korea
  • P. Buaphad, I.G. Jeong, Y.J. Joo, H.R. Lee
    University of Science and Technology of Korea (UST), Daejeon, Republic of Korea
  • M.-H. Chun, I.H. Yu
    PAL, Pohang, Kyungbuk, Republic of Korea
  • Y. Kim
    KAERI, Jeongeup-si, Republic of Korea
  Korea Atomic Energy Research Institute (KAERI) has been operating a 20 MeV superconducting RF linear accelerator (SRF LINAC) to conduct research on atom/nuclear reaction using neutron Time-Of-Flight (nTOF). It can accelerate electron beams up to 20 MeV with 1 kW continuous wave (CW) operation mode. Unfortunately, this machine has been aged over 15 years that brings about considerably difficulty in normal operation due to the performance degradation of sub-systems. To improve the operation condition of 20 MeV SRF LINAC, we has been carrying out an upgrade project with replacement and repair of old sub-systems from 2018. This paper describes a design study of Low-Level RF (LLRF) feedback system to raise the stability and acceleration efficiency of the electric field generated in the superconducting RF cavity structure in 20 MeV SRF LINAC.  
poster icon Poster TUPLH17 [0.643 MB]  
TUPLH18 NSLS-II Inject Linac RF Control Electronics Upgrade -1
  • H. Ma
    BNL, Upton, New York, USA
  Funding: US DOE
The electron LINAC injector of NSLS-II synchrotron light-source runs both Single-Bunch beam and long Multi-Bunch beam of up to 150 bunches. The key component for achieving this dual injector beam mode support capability is a high-speed rf modulator (or RFM) in the LINAC RF electronics front-end, which performs the necessary rf control and the beam loading compensation of different injection beams. The original LINAC rf electronics front-end successfully supported the machine commissioning and meets the basic needs of the machine operation. The upgrade being pursued is focused on improving the RFM control performance through replacing the current analog implementation in the RFM with a much more capable digital implementation, while still maintaining the necessary control bandwidth that is required for long and short Multi-Bunch beams. A variety of modern COTS rf transmission/reception DSP technology will be incorporated in the new design. The improvement in the reliability of network connection between the RFM’s and their host server is another focus in the upgrade, and the solution includes the adoption of the COTS TCP/IP and other communication protocol offload engines.
TUPLH19 Upgrade and Operation Experience of Solid-State Switching Klystron Modulator in NSLS-II Linac -1
  • H. Ma, J. Rose
    BNL, Upton, New York, USA
  Funding: US DOE
The NSLS-II synchrotron light-source at BNL uses three S-band, 45MW klystrons in its injector LINAC. At the core of the klystron station design is the novel solid-state switching modulators (or SSM). Compared to the conventional PFN klystron modulators, the main advantages of the SSM include the compact size requiring a smaller footprint in the LINAC, and a very flat top in the produced klystron HV pulses. The flatness of the HV pulses is very important for NSLS-II LINAC that runs multi-bunch beams to keep the beam energy dispersion within the tolerance. The principle of the SSM is fairly simple. It uses a large number of relatively low-voltage switched charging capacitor cells (or SU’s) in parallel. A specially designed, high step-up ratio, pulse transformer in the oil-tank with the same number of primary windings (as SU’s) combines the power from all the SU’s, and steps up to the required ~300kV klystron beam voltage. The operation experience at NSLS-II has proven the performance and reliability of the SSM’s. The BNL Model K2 SSM’s are currently being upgraded to Model K300 to run more powerful, and more cost-effective Canon’s E37302A klystrons.
TUPLH20 Commissioning of the CESR Upgrade for CHESS-U -1
  • J.P. Shanks, G.W. Codner, M.J. Forster, D.L. Rubin, S. Wang, L. Ying
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  Funding: Funding for the CHESS-U upgrade provided by New York State Capital Grant #AA737 / CFA #53676
The Cornell Electron Storage Ring (CESR) was upgraded in the second half of 2018 to become a dedicated synchrotron light source, CHESS-U. The upgrade is by far the largest modification to CESR in its 40-year history, replacing one-sixth of the storage ring with six new double-bend achromats, increasing beam energy from 5.3 GeV to 6.0 GeV, and switching from two counter-rotating beams to a single on-axis positron beam. The new achromats include combined-function dipoles, a first in CESR, and reduce the horizontal emittance by a factor of four. Eight compact narrow-gap undulators (4.6mm vacuum chamber aperture) and one high-energy 24-pole wiggler feed a total of six new and five existing x-ray end stations from a single positron beam. Commissioning of CHESS-U took place in the first half of 2019. We report on the methods and results of beam commissioning, including initial beam accumulation, optics correction, characterization, and commissioning of compact permanent-magnet insertion devices.
Simulation Analysis and Optimization of Fresh-Slice Techniques in LCLS and LCLS-II  
  • Z.H. Guo, Z. Huang
    Stanford University, Stanford, California, USA
  • M.W. Guetg, A.A. Lutman
    SLAC, Menlo Park, California, USA
  The recent demonstration of Fresh-slice lasing control enhanced the power performance and delay control for multi-color operation over the basic split undulator concept, improved the power for self-seeded operation and enabled production of high power single spectral spike femtosecond pulses in the soft X-rays. We present a start-to-end simulation study on fresh-slice techniques in LCLS and LCLS-II. The simulation has been validated reproducing experimental results of the multi-stage amplification experiment in terms of spikes energy, bandwidth and statistics, using LCLS parameters. We show that the FEL performance based on fresh-slice techniques can be further improved by the tunable undulator gap in LCLS-II.  
TUPLH24 Performance of CeC PoP Accelerator -1
  • I. Pinayev, Z. Altinbas, J.C. Brutus, A.J. Curcio, A. Di Lieto, T. Hayes, R.L. Hulsart, P. Inacker, Y.C. Jing, V. Litvinenko, J. Ma, G.J. Mahler, M. Mapes, K. Mernick, K. Mihara, T.A. Miller, M.G. Minty, G. Narayan, I. Petrushinapresenter, F. Severino, K. Shih, Z. Sorrell, J.E. Tuozzolo, E. Wang, G. Wang, A. Zaltsman
    BNL, Upton, New York, USA
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Coherent electron cooling experiment is aimed for demonstration of the proof-of-principle demonstration of reduction energy spread of a single hadron bunch circulating in RHIC. The electron beam should have the required parameters and its orbit and energy should be matched to the hadron beam. In this paper we present the achieved electron beam parameters including emittance, energy spread, and other critical indicators. The operational issues as well as future plans are also discussed.
poster icon Poster TUPLH24 [11.182 MB]