Keyword: photon
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MOPOB07 Off-Orbit Ray Tracing Analysis for the APS-Upgrade Storage Ring Vacuum System ion, vacuum, storage-ring, site 82
 
  • J.A. Carter, K.C. Harkay, B.K. Stillwell
    ANL, Argonne, Illinois, USA
 
  Funding: Argonne National Laboratory's work was supported by the U.S. Department of Energy, Office of Science under contract DE-AC02-06CH11357.
A MatLab program has been created to investigate off-orbit ray tracing possibilities for the APS-Upgrade stor-age ring vacuum system design. The goals for the pro-gram include calculating worst case thermal loading conditions and finding minimum shielding heights for photon absorbers. The program computes the deviation possibilities of synchrotron radiation rays emitted along bending magnet paths using discretized local phase space ellipses. The sizes of the ellipses are computed based on multi-bend achromat (MBA) lattice parameters and the limiting aperture size within the future storage ring vacuum system. For absorber height calculations, rays are projected from each point in the discretized ellipse to the locations of downstream absorbers. The absorber heights are mini-mized while protecting downstream components from all possible rays. For heat loads, rays are projected until they hit a vacuum chamber wall. The area and linear power densities are calculated based on a ray's distance trav-elled and striking incidence angle. A set of worse case local heat loads is collected revealing a maximum condi-tion that each vacuum component must be designed to withstand.
 
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB07  
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MOPOB11 Research and Development on the Storage Ring Vacuum System for the APS Upgrade Project ion, vacuum, storage-ring, impedance 92
 
  • B.K. Stillwell, B. Brajuskovic, J.A. Carter, H. Cease, R.M. Lill, G. Navrotski, J. R. Noonan, K.J. Suthar, D.R. Walters, G.E. Wiemerslage, J. Zientek
    ANL, Argonne, Illinois, USA
  • M.P. Sangroula
    IIT, Chicago, Illinois, USA
 
  Funding: UChicago Argonne, LLC, operator of Argonne National Laboratory, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357.
A number of research and development activities are underway at Argonne National Laboratory to build confidence in the designs for the storage ring vacuum system required for the Advanced Photon Source Upgrade project (APS-U) [1]. The predominant technical risks are: excessive residual gas pressures during operation, insufficient beam position monitor stability, excessive beam impedance, excessive heating by induced electrical surface currents, and insufficient operational reliability. Present efforts to mitigate these risks include: building and evaluating mock-up assemblies, performing mechanical testing of chamber weld joints, developing computational tools, investigating design alternatives, and performing electrical bench measurements. Status of these activities and some of what has been learned to date will be shared.
*B. Stillwell et al., Conceptual Design of a Storage Ring Vacuum System Compatible with Implementation of a Seven Bend Achromat Lattice at the APS, in Proc. IPAC'14, Dresden, Germany, 2409-2411.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB11  
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TUPOA54 Examination of Out-of-Field Dose and Penumbral Width of Flattening Filter Free Beams in Medical Linear Accelerators ion, linac, ECR, radiation 396
 
  • L.C. Bennett, O.N. Vassiliev
    M.D.A.C.C., Houston, Texas, USA
 
  Medical linear accelerators (LINACS) have traditionally used a flattening filter to ensure that the photon spectrum entering the patient was homogeneous within a given field size. Recently, leading manufacturers of medical accelerators have begun including an option for Flattening Filter Free (FFF) beams on their accelerators. These beams are characterized by a softer spectrum (lower average energy), peaked profiles, and less side scatter. Previous work with Monte Carlo models has shown that the elimination of the flattening filter from the beam path has the potential to greatly reduce scatter in regions immediately adjacent to the primary field (Kry 2010); however, systematic in-depth investigation of these effects has yet to be done using actual measurements from a linac equipped with FFF beams. We have examined and compared measurements of different energy pairings of FFF and FF beams from the Varian TrueBeam accelerators and found reductions of peripheral dose at upwards of 30% for the FFF beams and nearly 5% reduction in penumbral width at nearly all depths and field sizes; reductions were greatest for shallow depths and small field size.
Kry et al. Out-of-field photon dose following removal of the flattening filter from a medical accelerator. Physics in Medicine and Biology. vol. 55, no. 8, 2010. pp 2155-2166.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUPOA54  
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TUB4CO03 Optimization of Compton Source Performance Through Electron Beam Shaping ion, electron, radiation, brightness 474
 
  • A. Malyzhenkov, N.A. Yampolsky
    LANL, Los Alamos, New Mexico, USA
 
  We investigate a novel scheme for significantly increasing the brightness of x-ray light sources based on inverse Compton scattering (ICS) - scattering laser pulses off relativistic electron beams. The brightness of these sources is limited by the electron beam quality since electrons traveling at different angles, and/or having different energies, produce photons with different energies. Therefore, the spectral brightness of the source is defined by the 6d electron phase space shape and size, as well as laser beam parameters. The peak brightness of the ICS source can be maximized then if the electron phase space is transformed in a way so that all electrons scatter off the x-ray photons of same frequency in the same direction. We describe the x-ray photon beam quality through the Wigner function (6d photon phase space distribution) and derive it for the ICS source when the electron and laser rms matrices are arbitrary. We find the optimal uncorrelated electron beam phase space distribution resulting in the highest brightness of the ICS source for the simple on axis case as an example.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUB4CO03  
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TUB4CO04 Progress on the Magnetic Performance of Planar Superconducting Undulators ion, undulator, quadrupole, octupole 477
 
  • M. Kasa, C.L. Doose, J.D. Fuerst, E. Gluskin, Y. Ivanyushenkov
    ANL, Argonne, Illinois, USA
 
  Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
One of the primary goals of the superconducting undulator (SCU) program at the Advanced Photon Source (APS) is to achieve a high quality undulator magnetic field without the need for magnetic shimming to tune the device. Over the course of two years, two SCUs were designed, manufactured, assembled, and tested at the APS. Both SCUs were one meter in length with a period of 1.8 cm. After magnetic measurements of the first undulator were completed, several design changes were made in order to improve the quality of the undulator magnetic field. The design modifications were implemented during construction and assembly of the second SCU. The details of the design modifications along with a comparison of the magnetic measurement results will be described.
 
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-TUB4CO04  
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WEPOA13 RF Design and Simulation of a Non-Periodic Lattice Photonic Band Gap (PBG) Accelerating Structure ion, lattice, cavity, wakefield 716
 
  • N. Zhou, A. Nassiri
    ANL, Argonne, Illinois, USA
 
  Photonic Band Gap (PBG) structures (metallic and or dielectric) have been proposed for accelerators. These structures act like a filter, allowing RF field at some frequencies to be transmitted through, while rejecting RF fields in some (unwanted) frequency range. Additionally PBG structures are used to support selective field patterns (modes) in a resonator or waveguide. In this paper, we will report on the RF design and simulation results of an X-band PBG structure, including lattice optimization, to improve RF performance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA13  
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WEPOA51 Update on Photonic Band Gap Accelerating Structure Experiment ion, experiment, wakefield, higher-order-mode 807
 
  • J. Upadhyay, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
 
  Photonic band gap (PBG) structures have great potential in filtering higher order modes (HOMs) without perturbing the fundamental mode and in suppressing the wakefields. An efficient PBG structure would help a lot in terms of beam quality for high beam current future free-electron lasers (FEL). An improved design of X-band normal conducting PBG accelerating structure with elliptical rods will be presented. A comparison of cavity parameters between cylindrical and elliptical shape rod PBG structures will be shown. This new optimized PBG structure would be fabricated and tested at Argonne Wakefield Accelerator (AWA) test facility. The status of the test will be reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOA51  
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WEPOB11 Tuning of the APS Linac Accelerating Cavities After Structural Re-Alignment ion, linac, cavity, cathode 910
 
  • T.L. Smith, G.J. Waldschmidt
    ANL, Argonne, Illinois, USA
 
  A new S-band LCLS type Photo-cathode (PC) gun was recently installed in the APS linac. As a consequence, it was recognized that many of the linac accelerating structures were out of their 1mm straightness tolerances. In order to reduce the effects of wakefield on the beam, several of the misaligned structures were straightened. This paper discusses the bead-pull RF measurements, the effect of the straightening efforts on rf and the cell to cell retuning efforts that were performed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB11  
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WEPOB13 Online Minimization of Vertical Beam Sizes at APS ion, storage-ring, operation, lattice 916
 
  • Y.P. Sun
    ANL, Argonne, Illinois, USA
 
  In this paper, online minimization of vertical beam sizes along the APS (Advanced Photon Source) storage ring is presented. A genetic algorithm (GA) was developed and employed for the online optimization in the APS storage ring. A total of 59 families of skew quadrupole magnets were employed as knobs to adjust the coupling and the vertical dispersion in the APS storage ring. Starting from initially zero current skew quadrupoles, small vertical beam sizes along the APS storage ring were achieved in a short optimization time of one hour. The optimization results from this method are briefly compared with the one from LOCO (Linear Optics from Closed Orbits) response matrix correction.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB13  
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WEPOB18 Bend Magnet Head Loads and Out of Orbit Scenarios ion, software, electron, lattice 931
 
  • T.T. Valicenti, J.A. Carter, P.K. Den Hartog, K.J. Suthar
    ANL, Argonne, Illinois, USA
 
  This paper presents an analytical calculation of the spatial power spectrum emitted from relativistic electrons passing through a series of bend magnets. Using lattice files from the software Elegant, both the ideal and missteered trajectories taken by the beam are considered in determination of the power profile. Calculations were performed for the Advanced Photon Source Upgrade multi-bend-achromat storage-ring. Results were validated with Synrad, a monte-carlo based program designed at CERN. The power distribution and integrated total power values are in agreement with Synrad's results within one percent error. The analytic solution used in this software gives a both quick and accurate tool for calculating the heat load on a photon absorber. The location and orientation can be optimized in order to reduce the peak intensity and thus the maximum thermal stress. This can be used with any optimization or FEA software and gives rise to a versatile set of uses for the developed program.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB18  
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WEPOB70 Mechanical Straightening of the 3-m Accelerating Structures at the Advanced Photon Source ion, linac, operation, alignment 1051
 
  • D.J. Bromberek, W.G. Jansma, T.L. Smith, G.J. Waldschmidt
    ANL, Argonne, Illinois, USA
 
  A project is underway at the Advanced Photon Source to mechanically straighten the thirteen 3 meter accelerating structures in the Linac in order to minimize transverse wakefield, and improve charge transport efficiency and beam quality. Flexure supports allow positioning of the structures in the X & Y directions. Mechanical design of the flexure support system, straightening techniques, mechanical measurement methods, and mechanical & RF results will be discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB70  
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THA1CO06 Status of the Development of Superconducting Undulators for Storage Rings and Free Electron Lasers at the Advanced Photon Source undulator, ion, vacuum, operation 1068
 
  • Y. Ivanyushenkov, C.L. Doose, J.F. Fuerst, E. Gluskin, K.C. Harkay, Q.B. Hasse, M. Kasa, Y. Shiroyanagi, D. Skiadopoulos, E. Trakhtenberg
    ANL, Argonne, Illinois, USA
  • P. Emma
    SLAC, Menlo Park, California, USA
 
  Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
Development of superconducting undulator (SCU) technology continues at the Advanced Photon Source (APS). Experience of building and successful operation of the first short-length, 16-mm period length superconducting undulator SCU0 paved a way for the second 1-m long, 18-mm period device, SCU1, which is in operation since May 2015. The APS SCU team has also built and tested a 1.5-m long, 21-mm period undulator as a part of LCLS SCU R&D program aiming at demonstration of SCU technology availability for free electron lasers. This undulator successfully achieved all the requirements including a phase error of 5 degree rms. Our team is currently completing one more 1-m, 18-mm period undulator that will replace the SCU0. We are also working on a helical SCU for the APS. The status of these projects will be presented.
 
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THA1CO06  
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THB2IO02 Production of Medical Isotopes With Electron Linacs ion, target, radiation, electron 1091
 
  • D.A. Rotsch, K. Alford, J.L. Bailey, D.L. Bowers, T. Brossard, M.A. Brown, S. Chemerisov, D. Ehst, J.P. Greene, R. Gromov, J.J. Grudzinski, L. Hafenrichter, A.S. Hebden, T.A. Heltemes, W.F. Henning, J. Jerden, C.D. Jonah, M. Kalensky, J.F. Krebs, V. Makarashvili, B.J. Micklich, J.A. Nolen, K.J. Quigley, J.F. Schneider, N.A. Smith, D.C. Stepinski, P. Tkac, G.F. Vandegrift, M. Virgo, K.A. Wesolowski, A.J. Youker
    ANL, Argonne, Illinois, USA
  • Z. Sun
    SCSU, Orangeburg, South Carolina, USA
 
  Radioisotopes play important roles in numerous areas ranging from medical treatments to national security and basic research. Radionuclide production technology for medical applications has been pursued since the early 1900s both commercially and in nuclear science centers. Many medical isotopes are now in routine production and are used in day-to-day medical procedures. Despite these advancements, research is accelerating around the world to improve the existing production methodologies as well as to develop novel radionuclides for new medical applications. Electron linear accelerators (linacs) are unique sources of radioisotopes. Even though the basic technology has been around for decades, only recently have electron linacs capable of producing photons with sufficient energy and flux for radioisotope production become available. Housed in Argonne National Laboratory's building 211 is a newly upgraded 50 MeV/30-kW electron linear accelerator, capable of producing a wide range of radioisotopes. This talk will focus on the work being performed for the production of the medical isotopes 99Mo (99Mo/99mTc generator), 67Cu, and 47Sc.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THB2IO02  
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THPOA50 Development of an Optical Cavity for LCS Sources at the Compact ERL cavity, ion, laser, electron 1204
 
  • T. Akagi, S. Araki, Y. Honda, A. Kosuge, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  • R. Hajima, M. Mori, R. Nagai, T. Shizuma
    QST, Tokai, Japan
 
  High-energy photons from the laser Compton scattering (LCS) sources are expected to be applied in various fields in a wide range photon energies from keV to GeV. High-flux and narrow-bandwidth LCS photon beam is realized in an energy recovery linac (ERL). An electron beam of high-average current and small-emittance collides with accumulating laser pulses in an enhancement cavity for generating high-flux LCS photon beam. We have developed the high-finesse bow-tie ring cavity for the LCS experiment at the Compact ERL (cERL) in KEK. In this presentation, we will report the detail of the optical cavity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA50  
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THPOA51 Improvement of X-Ray Generation by Using Laser Compton Scattering in Laser Undulator Compact X-Ray Source(LUCX) ion, laser, gun, electron 1207
 
  • M.K. Fukuda, S. Araki, Y. Honda, Y. Sumitomo, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  • K. Sakaue
    Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
  • M. Washio
    RISE, Tokyo, Japan
 
  Funding: This work was supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
We have been developing a compact X-ray source based on the laser Compton scattering(LCS) at Laser Undulator Compact X-ray source(LUCX) accelerator in KEK. We have started to take X-ray images such as refraction contrast images and phase contrast imaging with Talbot interferometer. In this accelerator, 6-10keV X-rays are generated by LCS. An electron beam is produced by a 3.6cell RF-gun and accelerated to 18-24MeV by a 12cell accelerating tube. A laser pulse is stored in a 4-mirror planar optical cavity to enhance the power. To increase the flux of LCS X-rays, we perform an optimization of the beam-loading compensation, improvement of the intensity of an electron beam and a laser light at the collision point. We report the result of the X-ray generation in this accelerator.
 
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THPOA53 Luminosity Increase in Laser-Compton Scattering by Crab Crossing Method ion, electron, laser, luminosity 1213
 
  • Y. Koshiba, D. Igarashi, S. Ota, T. Takahashi, M. Washio
    RISE, Tokyo, Japan
  • K. Sakaue
    Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
  • J. Urakawa
    KEK, Ibaraki, Japan
 
  In collider experiments such as KEKB, crab crossing method is a promising way to increase the luminosity and KEK (High Energy Accelerator Research Organization) has achieved the luminosity record in 2009. We are planning to apply crab crossing to laser-Compton scattering, which is a collision of electron beam and laser, to gain a higher luminosity leading to a higher brightness X-ray source. It is well known that the collision angle between electron beam and laser affects the luminosity. It is the best when the collision angle is zero, head-on collision, to get a higher luminosity but difficult to construct such system especially when using an optical cavity for laser. Concerning this difficulty, we are planning crab crossing by tilting the electron beam using an rf-deflector. Although crab crossing in laser-Compton scattering has been already proposed*, nowhere has demonstrated yet. We are going to demonstrate and conduct experimental study at our compact accelerator system in Waseda University. In this conference, we will report about our compact accelerator system, laser system for laser-Compton scattering, and expected results of crab crossing laser-Compton scattering.
*V. Alessandro, et al. "Luminosity optimization schemes in Compton experiments based on Fabry-Perot optical resonators." Physical Review Special Topics-Accelerators and Beams 14.3 (2011): 031001.
 
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THPOA69 Evolution of the Design of the Magnet Structure for the APS Planar Superconducting Undulators ion, undulator, insertion-device, insertion 1245
 
  • E. Trakhtenberg, Y. Ivanyushenkov, M. Kasa
    ANL, Argonne, Illinois, USA
 
  Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357
Abstract A number of superconducting planar undulators (SCU) with different pole gaps and periods were designed, manufactured, and successfully operated at the Advanced Photon Source (APS) storage ring. A key component of the project is the precision machining of the magnet structure and the precision of the coil winding. The design of the magnet core had a number of modifications during the evolution of the design in order to achieve the best magnetic performance. The current design of the magnet structure is based on the assembled jaws with individual poles, while previous designs utilized solid cores with machined coil grooves. The winding procedure also changed from the first test cores to the current final design. Details of the magnet structure's design, manufacturing, winding and jaw assembly, and changes made from the first prototype system to the production unit, are presented.
[1] Status of the First Planar Superconducting Undulator for the Advanced Photon Source, Y. Ivanyushenkov, E.M. Trakhtenberg et al., Proc. in IPAC-2012, New Orleans, May 2012.
 
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