Keyword: photon
Paper Title Other Keywords Page
MOPWA009 Channeling Radiation Experiment at Fermilab ASTA electron, brilliance, experiment, detector 95
 
  • D. Mihalcea, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • D.R. Edstrom, P. Piot, T. Sen
    Fermilab, Batavia, Illinois, USA
  • W.D. Rush
    KU, Lawrence, Kansas, USA
  
  Electron beams with moderate energy ranging from 4 to 50 MeV can be used to produce x-rays through the Channeling Radiation (CR) mechanism. Typically, the x-ray spectrum from these sources extends up to 140 keV and this range covers the demand for most practical applications. The parameters of the electron beam determine the spectral brilliance of the x-ray source. The electron beam produced at the Fermilab new facility Advanced Superconducting Test Accelerator (ASTA) meets the requirements to assemble an experimental high brilliance CR x-ray source. In the first stage of the experiment the energy of the beam is 20 MeV and due to the very low emittance (100 nm) at low bunch charge (20 pC) the expected average brilliance of the x-ray source is 0.8x107 photons/[s-(mm-mrad)2-0.1%BW]. In the second stage of the experiment the beam energy will be increased to 50 MeV and consequently the average brilliance will be 4.8x108 photons/[s-(mm-mrad)2-0.1%BW]. Also, the x-ray spectrum will be extended from about 30 keV to 140 keV.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA009  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPWA021 Transverse Resonance Island Buckets at the MLS and BESSY II resonance, operation, radiation, electron 138
 
  • M. Ries, J. Feikes, T. Goetsch, P. Goslawski, J. Li, M. Ruprecht, A. Schälicke, G. Wüstefeld
    HZB, Berlin, Germany
  
  By operating the Metrology Light Source (MLS) near horizontal resonances (fx/frev=1/2, 1/3 or 1/4), two, three or four resonance island buckets may be populated for beam storage. This paper presents experimental results and operational experience such as tuning the machine for high current, controlling inter-bucket diffusion rates, improving overall lifetime and extraction of radiation pulses with sub-revolution repetition rate. First approaches to transfer this mode of operation to the BESSY II storage ring will also be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA021  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPWA023 Preserving Information of the Three Spatial Electron Beam Dimensions in One Streak Camera Measurement operation, electron, synchrotron, diagnostics 144
 
  • M.T. Switka, W. Hillert
    ELSA, Bonn, Germany
  
  Funding: Work funded by the DFG within SFB/TRR16
At the pulse stretcher ring ELSA, a streak camera is used for the analysis of visible synchrotron radiation. It functions as fast time resolving beam diagnostic apparatus capable of visualizing dynamics down to the picosecond time range. The optical beamline splits the photon beam and projects the electron beam's image onto the streak camera with transversely perpendicular orientation and slight displacement, thereby providing simultaneous imaging of both transverse planes. Thus, the information of bunch and beam dynamics in three dimensions is preserved and can be observed in slow sweep or synchroscan operation. Characteristics and exemplary measurements, demonstrating the capabilities and limits of this technique, are presented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA023  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPJE071 New Electron Cloud Detectors for the CERN Proton Synchrotron electron, detector, proton, extraction 476
 
  • C. Yin Vallgren, P. Chiggiato, S.S. Gilardoni, H. Neupert, M. Taborelli
    CERN, Geneva, Switzerland
  
  Electron cloud (EC) has already been observed during normal operation of the PS using classical shielded button pick-up detectors in drift sections. In the context of the LHC Injector Upgrade (LIU project), similar measurements are also needed for the combined function magnets of the machine, where the access to the vacuum chamber is strongly limited by the presence of the yoke. Two new electron cloud detectors have been studied, developed, and installed during the Long Shutdown (LS1) in one of such magnets. The first is based on current measurement by using a shielded button-type pick-up with a special geometry to reach the bottom surface of the vacuum pipe embedded in the magnet. The second one relies on a newly developed measurement method based on detection of the photons, which are emitted by cathodoluminescence from the electron cloud impinging on the vacuum chamber walls. Part of the emitted photons is collected through a quartz window by a Micro-Channel Plate Photomultiplier Tube (MCP-PMT). First results obtained during machine development runs show the feasibility of the photon detection scheme. The results are discussed and compared with pick-up measurements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE071  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPMA008 Simulation of Gas-Scattering Lifetime using Position- and Species-Dependent Pressure and Aperture Profiles scattering, vacuum, simulation, storage-ring 546
 
  • M. Borland, J.A. Carter, H. Cease, B.K. Stillwell
    ANL, Argonne, Ilinois, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
When computing gas-scattering lifetime for storage rings, it is common to use the average pressure, even though it is known that the pressure varies with location in the ring and varies differently for different gas species. In addition, other simplifications are commonly made, such as assuming that the apertures in the horizontal and vertical planes are independent and assuming that the momentum acceptance can be characterized by a single value. In this paper, we describe computation of the elastic- and bremsstrahlung-scattering lifetimes that includes species-specific gas pressure profiles computed with VACCALC and MOLFLOW. In addition, the computations make use of the detailed shape of the dynamic acceptance and the position-dependent momentum acceptance. Comparisons are made to simpler methods for the Advanced Photon Source storage ring and the multi-bend achromat upgrade lattice. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA008  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPMA031 Simulations of Diamond Detectors with Schottky Contacts electron, simulation, detector, scattering 617
 
  • G.I. Bell, J.R. Cary, D.A. Dimitrov, D. Meiser, D.N. Smithe, C.D. Zhou
    Tech-X, Boulder, Colorado, USA
  • M. Gaowei, E.M. Muller
    SBU, Stony Brook, New York, USA
  • J. Smedley
    BNL, Upton, Long Island, New York, USA
  
  Funding: This work is supported by the US DOE Office of Science, department of Basic Energy Sciences, grant numbers DE-SC0006246 and DE-SC0007577.
We present simulations of semiconductor devices using the code VSim (formerly Vorpal). The 3D simulations involve the movement and scattering of electrons and holes in the semiconductor, voltages which may be applied to external contacts, and self-consistent electrostatic fields inside the device. Particles may experience a Schottky barrier when moving between the semiconductor and a metal contact. Example devices include MOSFETs as well as a diamond X-ray detector. Our code VSim includes scattering models for GaAs and diamond, and runs in parallel on thousands of processors. We compare our simulation results with experimental results from a prototype diamond X-ray detector. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA031  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPHA037 Visible Light Diagnostics at the ANKA Storage Ring synchrotron, diagnostics, detector, radiation 866
 
  • B. Kehrer, A. Borysenko, E. Hertle, N. Hiller, M. Holz, A.-S. Müller, P. Schönfeldt, P. Schütze
    KIT, Karlsruhe, Germany
  
  Synchrotron radiation in the visible light range is a versatile diagnostics tool for accelerator studies. At the ANKA storage ring of the Karlsruhe Institute of Technology (KIT), we have a dedicated visible light diagnostics beamline and two additional beam ports close to the radiation's source point. The visible light diagnostics beamline hosts a time-correlated single-photon-counting unit to measure the bunch filling pattern and a streak camera for longitudinal diagnostics. Recently, the beamline has been extended with a fast-gated intensified camera to study transverse instabilities. The synchrotron light monitor ports were previously used for direct source imaging. Due to the diffraction limit the vertical beam size could not be resolved. One of the two ports has recently been equipped with a double-slit to allow for interferometric measurements of the vertical beam size. In this paper we give an overview of the different setup modifications and present first results.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPHA037  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPHA040 First Results of Energy Measurements with a Compact Compton Backscattering Setup at ANKA laser, electron, detector, storage-ring 876
 
  • C. Chang, E. Bründermann, E. Hertle, N. Hiller, E. Huttel, A.-S. Müller, M.J. Nasse, M. Schuh, J.L. Steinmann
    KIT, Karlsruhe, Germany
  • H.-W. Hübers, H. Richter
    DLR, Berlin, Germany
  
  Funding: This work is funded by the European Union under contract PITN-GA-2011-289191
An electron energy measurement setup based on the detection of Compton backscattered photons, generated by laser light scattered off the relativistic electron beam, has been proposed and developed for operation at the ANKA storage ring of the Karlsruhe Institute of Technology (KIT). In contrast to conventional methods based on head-on collisions, the setup at ANKA is, for the first time, realized in a transverse configuration where the laser beam hits the electron beam at an angle of ~90°. This makes it possible to achieve a relatively low-cost and very compact setup since it only requires a small side-port instead of a straight section. This development could benefit storage rings with restricted space or where no straight sections are available, for example due to interferences with existing beamlines. The setup and the first measurement results are presented in the paper. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPHA040  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPTY062 The Energy Saving Processes for Utility System in TPS controls, experiment, operation, factory 1082
 
  • C.S. Chen, W.S. Chan, J.-C. Chang, Y.C. Chang, Y.-C. Chung, C.W. Hsu, C.Y. Liu, Z.-D. Tsai
    NSRRC, Hsinchu, Taiwan
  
  There are more and more non-linear electronic equipments such as inverters using in facility nowadays. These non-linear electronic equipments let us achieve energy saving, but induce other electrical pollution to the whole power grid in contrast. Among these electrical pollutions, electric harmonic is the most common and harmful to power facility. Therefore, how to monitor the electrical noises from these non-linear equipments becomes an important issue. In this article, a set of power quality monitoring system based on FPGA (Field-Programmable Gate Arrays) modules and PAC (Programmable Automatic Controller) has been built because of their programmability and fast processing speed. By using this monitoring system, any abnormality in power system and its spectrum will be recorded thoroughly. On the other hand, the maintainer could follow the trace of noise and then propose a suitable solution to eliminate the electrical interference too.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPTY062  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPWI014 Design and Development for the Next Generation X-ray Beam Position Monitor System at the APS undulator, background, electron, coupling 1175
 
  • B.X. Yang, G. Decker, Y. Jaski, S.-H. Lee, M. Ramanathan, N. Sereno, F. Westferro
    ANL, Argonne, Ilinois, USA
  
  Funding: Work performed at Argonne National Laboratory, operated by UChicago Argonne, LLC, for the U.S. Department of Energy under contract DE-AC02-06CH11357.
The proposed Advanced Photon Source (APS) Upgrade will bring storage-ring beam sizes down to several micrometers and require x-ray beam directional stability in 100 nrad range for undulator power exceeding 16 kW. The next generation x-ray beam position monitors (XBPMs) are designed to meet these requirements. We present first commissioning data on the recently installed grazing-incidence insertion device x-ray beam position monitor (GRID-XBPM) based on Cu K-edge x-ray fluorescence from limiting absorbers of the front end for two inline undulators. It demonstrated a 50-fold improvement for signal-to-background ratio over existing photoemission-based XBPMs. Techniques for calibrating the XBPMs will be discussed. We will also present a new XBPM design based Compton scattering from diamond blades. This XBPM is designed for less powerful undulators such as the APS canted-undulator beamlines where each undulator generates < 10 kW of beam power. We will discuss the thermal design of the blade, the optics design of the detector assembly, and computer simulations of expected response to the x-ray beam. Test data of the prototype may be presented if available. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWI014  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPWI052 Responsivity Study of Diamond X-ray Monitors with nUNCD Contact synchrotron, detector, plasma, database 1273
 
  • M. Gaowei, J. Smedley
    BNL, Upton, Long Island, New York, USA
  • E.M. Muller, T. Zhou
    SBU, Stony Brook, New York, USA
  • A.V. Sumant
    Argonne National Laboratory, Center for Nanoscale Materials, Argonne, USA
  
  Nitrogen doped ultrananocrystalline diamond (nUNCD) grown on the surface of a CVD single crystal diamond is tested at various beamlines covering an x-ray photon energy range of 200eV to 28 keV. The nUNCD has much lower x-ray absorption than metal contacts and is designed to improve the performance of our device. The responsivity of nUNCD diamond x-ray detector is compared with the conventional platinum coated diamond x-ray beam position monitor and the results are presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWI052  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUBC2 Multi-GHz Pulse-Train X-Band Capability for Laser Compton X-Ray and Gamma-Ray Sources laser, electron, brightness, scattering 1363
 
  • D.J. Gibson, G.G. Anderson, S.G. Anderson, C.P.J. Barty, R.A. Marsh, M. J. Messerly, M.A. Prantil
    LLNL, Livermore, California, USA
  
  Funding: This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
A wide variety of light-source applications would benefit from increased average brightness, which generally corresponds to increasing average current in the driving accelerator. Presented is an accelerator architecture that is capable of producing hundreds of electron bunches, spaced as close together as every RF cycle, which provides the chance to increase current while maintaining beam quality. This system relies on an X-band photoinjector and a photoinjection drive laser that is driven by the same rf source to ensure synchronization, and an interaction laser system designed to match the duty cycle of the electron pulse train. Results of the photoinjector laser performance and initial experimental measurements of beam quality in accelerated bunch trains are presented, along with a discussion of the impact on the performance of tunable, narrow-bandwidth x-ray and gamma-ray beams based on Compton-scattering. 		 
slides icon Slides TUBC2 [20.256 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUBC2  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPWA001 Measurement of the Incoherent Depth of Field Effect on Horizontal Beam Size Using a Synchrotron Light Interferometer electron, synchrotron, storage-ring, lattice 1391
 
  • M.J. Boland
    SLSA, Clayton, Australia
  • W.J. Corbett
    SLAC, Menlo Park, California, USA
  • T.M. Mitsuhashi
    KEK, Ibaraki, Japan
  
  The electron beam size as measured using synchrotron light in a circular accelerator is influenced by the incoherent depth of field effect. This effect comes about due to the instantaneous opening angle of the emitted synchrotron radiation (SR) and the acceptance angle of the SR light monitor beamline. Measurements were made using a visible light interferometer at the visible light beamlines in three circular accelerators at ATF, SPEAR3 and AS. The first order spatial coherence of the beam was measured and from that the horizontal beam size was calculated. The data is compared with a theory of synchrotron radiation with and without the horizontal incoherent field depth effect.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA001  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPWA007 UPGRADED OPTICS FOR SIRIUS WITH IMPROVED MATCHING OF ELECTRON AND PHOTON BEAM EMITTANCES optics, quadrupole, brightness, emittance 1407
 
  • L. Liu, N. Milas, A.H.C. Mukai, X.R. Resende, F. H. de Sá
    LNLS, Campinas, Brazil
  
  A new optics has been designed for Sirius with improved betatron function matching in the 6 meter-long low beta straight sections for insertion devices. Both horizontal and vertical betatron functions are set to 1.5 m in the center of the section, improving the matching of the electron and undulator photon beams. In addition, the horizontal beam stay clear has also been reduced allowing for small horizontal gap devices as well as the conventional small vertical gap ones. The new design optics has been optimized to the same previous performance regarding dynamic aperture and momentum acceptance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA007  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPWA012 SOLEIL Status Report undulator, operation, storage-ring, vacuum 1419
 
  • A. Nadji, Y.-M. Abiven, F. Bouvet, P. Brunelle, A. Buteau, N. Béchu, L. Cassinari, M.-E. Couprie, X. Delétoille, C. Herbeaux, N. Hubert, N. Jobert, M. Labat, J.-F. Lamarre, P. Lebasque, A. Lestrade, A. Loulergue, P. Marchand, O. Marcouillé, J.L. Marlats, L.S. Nadolski, R. Nagaoka, P. Prigent, K.T. Tavakoli, M.-A. Tordeux, M. Valléau
    SOLEIL, Gif-sur-Yvette, France
  
  The 2.75 GeV synchrotron light source SOLEIL (France) delivers photons to 27 beamlines and 2 new ones are under construction. The commissioning of the Femtoslicing operation mode involving two beamlines is in progress. The uniform filling pattern is now available to users with a 500 mA stored beam current. The operation of the two canted and long beamlines ANATOMIX and Nanoscopium both using in-vacuum insertion devices (IDs) as a photon source has been raising challenges still under investigation. Upgrades of crucial subsystem equipment like magnet power supplies, storage ring RF input power couplers, and solid state amplifiers are continuing. New user requests for beam stability are under upgrade consideration. Other projects for the storage ring are ongoing such as the design and construction of new insertion devices, new multipole injection kicker, localised small and round photon beam production, as well as R&D on 500 MHz solid-state amplifiers. In parallel first studies for a future upgrade of the machine have been progressing.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA012  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPWA019 A Canted Double Undulator System With a Wide Energy Range for EMIL undulator, optics, betatron, permanent-magnet 1442
 
  • J. Bahrdt, H.-J. Bäcker, W. Frentrup, S. Gottschlich, C. Rethfeldt, M. Scheer, B. Schulz
    HZB, Berlin, Germany
  
  At BESSY II a canted double undulator system for the Energy Materials In-situ Laboratory EMIL is under construction. The energy regime is covered with two undulators, an APPLE II undulator for the soft and a cryogenic permanent magnet undulator CPMU17 for the hard photons. The layout and the performance of the undulators are discussed in detail. The minimum of the vertical betatron function is shifted to the center of the CPMU17. The neighboring quadrupoles and an additional quadrupole between the undulators control the vertical betatron function. Prior to the undulator installation a testing chamber with four movable scrapers has been implemented at the CPMU17 location. Utilizing the scrapers the new asymmetric lattice optics is tested and evaulated.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPWA033 Status of the Soft X-ray Free Electron Laser FLASH operation, FEL, optics, laser 1482
 
  • M. Vogt, B. Faatz, J. Feldhaus, K. Honkavaara, S. Schreiber, R. Treusch
    DESY, Hamburg, Germany
  
  The superconducting free-electron laser FLASH at DESY routinely produces up to several thousand photon pulses per second with wavelengths in the soft X-ray and vacuum UV regime and with energies up to 0.5 mJ per pulse. In 2014 the assembly of a second undulator beamline, FLASH2, was finished. While recommissioning of the FLASH linac and the original FLASH1 beamline was finished already at the end of 2013, the commissioning of FLASH2 could only be started in early February 2014. Only a few weeks have been reserved for dedicated set up of FLASH2, and most of its commissioning has been performed parasitically during the FLASH1 user run. The first beam was extracted through the septum to the FLASH2 beamline on March 4th, 2014, and the first lasing of FLASH2 at a wavelength of about 40 nm was achieved on August 20th, while FLASH1 was lasing simultaneously with 250 bunches at 13.5 nm. We summarize here the status of the FLASH2 commissioning and the FLASH1 operation during its 5th user period.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA033  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPWA048 Radiative Cooled Target for the ILC Polarized Positron Source target, positron, vacuum, radiation 1526
 
  • A. Ushakov
    University of Hamburg, Hamburg, Germany
  • F. Dietrich, S. Riemann, T. Rublack
    DESY Zeuthen, Zeuthen, Germany
  • P. Sievers
    CERN, Geneva, Switzerland
  
  Funding: Work supported by the German Federal Ministry of Education and Research, Joint Research Project R&D Accelerator "Spin Optimization", contract number 19XL7IC4
The target for the polarized positron source of the future International Linear Collider (ILC) is designed as wheel of 1 m diameter spinning with 2000 revolutions per minute to distribute the heat load. The target system is placed in vacuum since exit windows would not stand the load. In the current ILC design, the positron target is assumed to be water-cooled. Here, as an alternative, radiative cooling of the target has been studied. The energy deposition in the target is the input for ANSYS simulations. They include the temperature evolution as well as the corresponding thermo-mechanical stress in the target components. A principal design is suggested for further consideration. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA048  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPWA055 DAΦNE Gamma-Ray Factory electron, laser, factory, emittance 1542
 
  • D. Alesini, S. Guiducci, C. Milardi, A. Variola, M. Zobov
    INFN/LNF, Frascati (Roma), Italy
  • I. Chaikovska, Z.F. Zomer
    LAL, Orsay, France
  
  Gamma sources with high flux and spectral densities are the main requirements for new nuclear physics experiments to be performed in several worldwide laboratories with dedicated facilities. The presentation is focalized on a proposal of experiment of gamma photons production using Compton collisions between the DAΦNE electron beam and a high average power laser pulse, amplified in a Fabry-Pérot optical resonator. The calculations show that the resulting gamma beam source has extremely interesting properties in terms of spectral density, energy spread and gamma flux comparable (and even better) with the last generation gamma sources. The energy of the gamma beam depends on the adopted laser wavelength and can be tuned changing the energy of the electron ring. In particular we have analyzed the case of a gamma factory tunable in the 2-9 MeV range. The main parameters of this new facility are presented and the perturbation on the transverse and longitudinal electron beam dynamics is discussed. A preliminary accelerator layout to allow experiments with the gamma beam is presented with a first design of the accelerator optics.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA055  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPWA059 Modeling of Photoemission and Electron Spin Polarization from NEA GaAs Photocathodes electron, scattering, polarization, simulation 1556
 
  • O. Chubenko, A. Afanasev
    GWU, Washington, USA
  
  Funding: Work supported by The George Washington University and Thomas Jefferson National Accelerator Facility.
Many nuclear-physics and particle-physics scientific laboratories, including Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (Jefferson Lab) which studies parity violation and nucleon spin structure, require polarized electron sources. At present, photoemission from strained GaAs activated to negative electron affinity (NEA) is a main source of polarized electrons. Future experiments at advanced electron colliders will require highly efficient polarized electron beams, which sets new requirements for photocathodes in terms of high quantum efficiency (QE) (>>1%) and spin polarization (~85%). Development of such materials includes modeling and design of photocathodes, material growth, fabrication of photocathodes, and photocathode testing. The purpose of the present work is to develop a semi-phenomenological model, which could predict photoemission and electron spin polarization from NEA GaAs photocathodes. Detailed Monte Carlo simulation and modeling of physical processes in photocathodes is important for optimization of their design in order to achieve high QE and reduce depolarization mechanisms. Electron-phonon interactions near the surface and influence of the presence of quantum heterostructures on the diffusion length are studied in depth. Simulation results will be compared to the experimental results obtained at Jefferson Lab and can be used to optimize the photocathode design and material growth, and thus develop high-polarization high-brightness electron source. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA059  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPWA061 Analyses of Light's Orbital Angular Momentum from Helical Undulator Harmonics radiation, undulator, polarization, emittance 1563
 
  • S. Sasaki, A. Miyamoto
    HSRC, Higashi-Hiroshima, Japan
  • M. Hosaka, N. Yamamoto
    Nagoya University, Nagoya, Japan
  • M. Katoh, T. Konomi
    UVSOR, Okazaki, Japan
  
  Funding: Partially supported by the Grant-in-Aid for Scientific Research, Japan Society for the Promotion of Science, and supported by the Joint Studies Program of the Institute for Molecular Science.
The phenomenon of higher harmonic radiation from a helical undulator carrying orbital angular momentum (OAM)* attracts a great deal of attention because this novel property may be used as a new probe for synchrotron radiation science** that would be performed in a diffraction limited light source facility such as the APS-II. Although a diffraction limited x-ray source does not yet exist, the 750 MeV UVSOR-III is already a diffraction limited light source in the UV region. In this ring, a tandem-aligned double-APPLE undulator system similar to that in BESSY-II*** is installed for FEL and coherent light source experiments. Using this set-up, we observed spiral interference patterns between two different harmonic radiations with a scanning fiber multi-channel spectrometer and a CCD camera placed at the end of BL1U Beamline. By these measurements, various interference patterns such as single, double, and triple spirals were observed which concur with the theoretical prediction for every mode in the right or left circular polarization. The rotation of an interference pattern by rotating a polarizer was also observed.
* S. Sasaki and I. McNulty, Phys. Rev. Lett. 100, 124801, 2008.
** M. VanVeenendaal and I. McNulty, Phys. Rev. Lett. 98, 157401 (2007).
*** J. Bahrdt, et al., Phys. Rev. Lett. 111, 034801, 2013. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA061  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPWA062 GaAs Photocathode Activation with CsTe Thin Film electron, cathode, vacuum, experiment 1567
 
  • M. Kuriki, Y. Seimiya, K. Uchida
    HU/AdSM, Higashi-Hiroshima, Japan
  • S. Kashiwagi
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
  
  Funding: This work is partly supported by MEXT/JSPS KAKENHI (Grant-in-Aid for scientific research) 24654054.
GaAs is an unique and advanced photocathode which can generate highly polarized and extremely low emittance electron beam. The photo-emission is possible up to 900nm wavelength. These advantages are due to NEA (Negative Electron Affinity) surface where the conduction band minimum is higher than the vacuum energy state. The NEA surface is artificially made with Cs-O/F evaporation on the cleaned GaAs surface, but the NEA surface is fragile, so that the emission is easily lost by poor vacuum environment and high emission density. NEA activation with any vital material is desirable. We found that the GaAs can be activated by CsTe thin film which is known as a vital photo-cathode material. The photo-electron emission spectrum extends up to 900 nm wavelength which corresponds to the band-gap energy of GaAs. The result strongly suggests that the surface becomes effectively NEA state by the CsTe thin film. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA062  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPWA064 Study of Inherent Potential for Emittance Reduction at the SPring-8 Storage Ring optics, brilliance, emittance, storage-ring 1573
 
  • Y. Shimosaki
    JASRI/SPring-8, Hyogo-ken, Japan
  
  A design study for an upgrade project of the SPring-8, the SPring-8-II, is in progress, which is a full-scale major lattice modification. Besides the design study for the SPring-8-II, an inherent potential of achieving much higher brilliance than that of the present SPring-8 has been explored for the general evaluation. In this paper, the evaluation of the inherent potential for the SPring-8, not for the SPring-8-II, in terms of increasing the brilliance is discussed.

 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA064  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPWA066 Development of a High Average Power Laser for High Brightness X-ray Source and Imaging at cERL laser, cavity, electron, detector 1579
 
  • A. Kosuge, T. Akagi, S. Araki, Y. Honda, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  • R. Hajima, M. Mori, T. Shizuma
    JAEA, Ibaraki-ken, Japan
  • R. Nagai
    JAEA/ERL, Ibaraki, Japan
  
  Funding: This study is supported by Photon and Quantum Basic Research Coordinated Development Program of MEXT, Japan.
High brightness X-rays via laser-Compton scattering (LCS) of laser photons stored in an optical cavity by a relativistic electron beam is useful for many scientific and industrial applications such as X-ray imaging. The construction of compact Energy Recovery Linac (cERL) is now in progress at KEK to generate low-emittance and high-current electron beams. In order to demonstrate the generation of high brightness LCS X-rays, it is necessary to develop a high average power injection laser and an optical four-mirror ring cavity with two concave mirrors which is used to produce a small spot laser beam inside the cavity. In this presentation, we will show the result of the development of the high average laser system, the LCS X-rays generation, and the X-ray imaging. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA066  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPJE002 Demonstration of High-flux Photon Generation from an ERL-based Laser Compton Photon Source laser, electron, cavity, linac 1607
 
  • R. Nagai, R. Hajima, M. Mori, T. Shizuma
    JAEA, Ibaraki-ken, Japan
  • T. Akagi, S. Araki, Y. Honda, A. Kosuge, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  
  A high-flux photon source from the laser Compton scattering (LCS) by an electron beam in an energy-recovery linac (ERL) is a key technology for a nondestructive assay system to identify nuclear materials. In order to demonstrate accelerator and laser technologies required for a LCS photon generation, a LCS photon source is under construction at the Compact ERL (cERL). The LCS photon source consists of a mode-locked fiber laser and a laser enhancement cavity. Flux monitors and a data aqcuisition system are also under construction. The commissioning of the LCS photon source will be started in February 2015 and LCS photon generation is scheduled in March 2015. The demonstration result of the LCS photon source will be presented in detail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE002  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPJE011 Laser-Compton Scattering X-ray Source Based on Normal Conducting Linac and Optical Enhancement Cavity laser, cavity, electron, linac 1635
 
  • K. Sakaue, M. Washio
    Waseda University, Tokyo, Japan
  • S. Araki, M.K. Fukuda, Y. Honda, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
  
  Funding: Work 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 via laser-Compton scattering (LCS) at KEK-LUCX (Laser Undulator Compact X-ray source) facility. The LUCX system is based on S-band normal conducting linac with an energy of 30 MeV and optical enhancement cavity for photon target. As a photon target, we invented a burst mode laser pulse storage technique for a normal conducting linac, which enables to store the high power laser pulses at the timing of electron bunchs. The peak storage power exceeds to more than 250 kW with 357 MHz repetition. Electron linac is under operation with multi-bunch mode, 1000 bunches/train with 600 pC charge in each bunches. We have succeeded to produce 1000 pulse/train LCS X-ray train. Combining high repetition rate electron linac and burst mode optical enhancement cavity, more than 109 ph./sec/10%b.w. flux would be possible. In this conference, the introduction of our test facility LUCX, recent expermental results, and future prospective including normal conducting LCS X-ray source will be presented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE011  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPJE021 Interaction Chamber Design for a Sub-MeV Laser-compton Gamma-ray Source laser, electron, scattering, simulation 1665
 
  • H.H. Xu, J.H. Chen, G.T. Fan, D. Wang, H.L. Wu, B.J. Xu
    SINAP, Shanghai, People's Republic of China
  
  Previously, fixed angle Laser-Compton Scattering (LCS) experiments have been conducted at the terminal of the 100MeV LINAC of the Shanghai Institute of Applied Physics, using SINAP-I* and SINAP-II** facility. Sub-MeV energy continuously tunable laser-Compton light source device (SINAP-Ⅲ) is an updated facility that will allow the collision angle between the laser and electron beam continuously adjustable from 20 to 160 degrees. This new feature will enable convenient control on the peak energy of the generated X/γ ray, especially when the energy of electrons cannot be momentarily adjusted, e.g. on the storage ring. The well control of the status of LCS is necessary. An interaction chamber containing a rotatable structure that holds a series of plane mirrors and convex lens is presented to achieve it. This work is a summary of its design. The simulation of photon production's variation caused by the system errors is performed using a MC code***. The accuracies of installation and adjustment of mirrors and lens are given according to the simulation results. The sizes of these optical devices are also optimized to make the chamber as compact as possible due to space limitation.
* W. Luo et al., Rev. of Sci. Instrum, 81 (2010) 013304
** W. Luo et al., Applied Physics B, 101 (2010)761-771
*** W. Luo et al., NIM A, 660 (2011), p. 108
 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE021  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPJE048 Orbit Correction and Stability Studies for Ultra-Low Emittance Storage Rings emittance, simulation, dipole, storage-ring 1728
 
  • M. Böge, M. Aiba, A. Streun
    PSI, Villigen PSI, Switzerland
  
  Ultra-low emittance storage rings exhibit extremely strong focusing and sextupolar chromaticity corrections. The therefore mandatory excellent centering of the closed orbit in the small aperture magnets is a challenging task and necessitates a proper beam diagnostics and correction layout. Correction and stability studies for a possible ultra-low emittance upgrade of the Swiss Light Source are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE048  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPJE050 Design of a Resonant Transition Radiation Source in the soft X-ray Range radiation, electron, resonance, vacuum 1735
 
  • P. Wang, K.C. Leou
    NTHU, Hsinchu, Taiwan
  • N.Y. Huang, W.K. Lau, A.P. Lee
    NSRRC, Hsinchu, Taiwan
  
  Resonant transition radiation (RTR) can be generated from multi-layer structures when they are driven by relativistic electron beams. In consideration of using the NSRRC 90 MeV photoinjector as driver, we examined the feasibility of generating narrow-band soft x-rays from various multi-layer structures. Based on analytical theory, the expected angular-spectral distribution and photon yield of these radiators are calculated and compared.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE050  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPJE064 Calibration of Fast Fiber-Optic Beam Loss Monitors for the Advanced Photon Source Storage Ring Superconducting Undulators undulator, simulation, electron, vacuum 1780
 
  • J.C. Dooling, K.C. Harkay, Y. Ivanyushenkov, V. Sajaev, A. Xiao
    ANL, Argonne, Ilinois, USA
  • A. Vella
    University of Illinois at Urbana-Champaign, Illinois, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of Science, under contract number DE-AC02-06CH11357.
We report on the calibration and use of fast fiber-optic (FO) beam loss monitors (BLMs) in the Advanced Photon Source storage ring (SR). A superconducting undulator prototype (SCU0) has been operating in SR Sector 6 since the beginning of CY2013, and another undulator SCU1 (a 1.1-m length undulator that is three times the length of SCU0) is scheduled for installation in Sector 1 in 2015. The SCU0 main coil often quenches during beam dumps. MARS simulations have shown that relatively small beam loss (<1 nC) can lead to temperature excursions sufficient to cause quenching when the SCU0 windings are near critical current. To characterize local beam losses, high-purity fused-silica FO cables were installed in Sector 6 next to the SCU0 cryostat and in Sector 1 where SCU1 will be installed. These BLMs aid in the search for operating modes that protect the SCU structures from beam-loss-induced quenching. In this paper, we describe the BLM calibration process that included deliberate beam dumps at locations of BLMs. We also compare beam dump events where SCU0 did and did not quench. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE064  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPJE067 Status of the APS Upgrade Project brightness, lattice, emittance, dipole 1791
 
  • S. Henderson
    ANL, Argonne, Ilinois, USA
  
  Funding: Work supported by U.S. Dept. of Energy, Office of Science, under Contract No. DE-AC02-06CH11357
A concept for an upgrade to the Advanced Photon Source based on a multi-bend achromat lattice is being developed at Argonne National Laboratory. An MBA upgrade to the APS will reduce the horizontal emittance by a factor of ~50. Coupled with superconducting undulators, the APS-U brightness will be two to three orders of magnitude beyond that which is available today at the APS. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE067  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPJE068 Development and Performance of 1.1-m Long Superconducting Undulator at the Advanced Photon Source undulator, dipole, operation, storage-ring 1794
 
  • 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, Ilinois, USA
  
  Funding: Work supported by U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
Development of superconducting undulators continues at the Advanced Photon Source (APS). The second superconducting undulator, SCU1, has been built and installed in the storage ring of the APS. This undulator has a 1.1-m long superconducting magnet and utilizes an improved version of the cryostat of the first superconducting undulator, SCU0. The results of the cold test of the SCU1, and its performance in the APS storage ring are presented in this paper. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE068  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPJE078 Modeling of Impedance Effects for the APS-MBA Upgrade impedance, vacuum, wakefield, simulation 1825
 
  • R.R. Lindberg
    ANL, Argonne, Illinois, USA
  • A. Blednykh
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Understanding the sources of impedance is critical to accelerator design, and only becomes more important as vacuum chambers become smaller and closer to the electron beam. The multibend achromat upgrade at the Advanced Photon Source (APS) requires small, 22-mm diameter vacuum chambers and even smaller (6 mm) gaps for the insertion devices, so that both rf heating and wakefield-driven transverse instabilities become important concerns. We discuss modeling the primary sources of geometric impedance using the electromagnetic finite difference codes GdfidL and ECHO, and how these codes are influencing vacuum and accelerator component design. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE078  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPMA001 Progress of the R&D towards a diffraction limited upgrade of the Advanced Light Source optics, injection, radiation, lattice 1840
 
  • C. Steier, A. Anders, D. Arbelaez, J.M. Byrd, K. Chow, S. De Santis, R.M. Duarte, J.-Y. Jung, T.H. Luo, A. Madur, H. Nishimura, J.R. Osborn, G.C. Pappas, L.R. Reginato, D. Robin, F. Sannibale, D. Schlueter, C. Sun, C.A. Swenson, W.L. Waldron, E.J. Wallén, W. Wan
    LBNL, Berkeley, California, USA
  
  Funding: This work was supported by the Laboratory Directed Research and Development Program of Lawrence Berkeley National Laboratory under U.S. Department of Energy Contract No. DE-AC02-05CH11231.
Improvements in brightness and coherent flux of about two orders of magnitude over operational storage ring based light sources are possible using multi bend achromat lattice designs. These improvements can be implemented as upgrades of existing facilities, like the proposed upgrade of the Advanced Light Source, making use of the existing infrastructure, thereby reducing cost and time needed to reach full scientific productivity on a large number of beamlines. An R&D program funded by internal laboratory funds was started at LBNL to further develop the technologies necessary for diffraction-limited storage rings (DLSR). It initially involves five areas, and focuses on the specific needs of soft x-ray facilities: vacuum system/NEG coating of small chambers, injection/pulsed magnets, RF systems/bunch lengthening, magnets/radiation production with advanced radiation devices, and beam physics design optimization. Some hardware prototypes have been built. The work will expand in the future to demonstrate necessary key technologies at the subsystem level or in beam tests and include new areas like photon beamline optics. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA001  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPMA030 Narrowband Continuously Tunable Radiation in the 5 to 10 Terahertz Range by Inverse Compton Scattering electron, laser, radiation, scattering 1901
 
  • Z. Wu, K. Fang, M.-H. Wang, J. Wu
    SLAC, Menlo Park, California, USA
  
  Funding: Work supported by U.S. Department of Energy under Grants DE-AC02-76SF00515, DE-FG02-13ER41970 and by DARPA Grant N66001-11-1-4199.
5 to 10 THz has recently become the frontier of THz radiation sources development, pushed by the growing interests of spectroscopy and pump-probe material study in this frequency range. This spectrum “Gap” lies in between the several THz range covered by Electro-Optical crystal based THz generation, and the tens of THz range covered by the difference frequency generation method. The state-of-the-art EO crystal THz source using tilted pulse front technique has been able to reach ~ 100 MV/m peak field strength, large enough to be used in an inverse Compton scattering process to push these low energy photons to shorter wavelengths of the desired 5-10 THz range. The required electron beam energy is within 1~2 MeV, therefore a compact footprint of the whole system. The process would occur coherently granted the electron beam is bunched to a fraction of the radiation wavelengths (several microns). A system operating at KHz or even MHz repetition rate is possible given the low electron energy and thus low RF acceleration gradient required. This work will explore the scheme with design parameters and simulation results. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA030  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPMA036 First e-/Photon Commissioning Results for the GlueX Experiment/Hall D at CEBAF radiation, detector, acceleration, target 1916
 
  • M.D. McCaughan, J. F. Benesch, Y. Roblin, T. Satogata
    JLab, Newport News, Virginia, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Experimental Hall D, with flagship experiment GlueX, was constructed as part of the 12 GeV CEBAF upgrade. A new magnetically extracted electron beam line was installed to support this hall. Bremsstrahlung photons from retractable radiators, are delivered to the experiment through a series of collimators following a long drift to allow for beam convergence. Coherent Bremsstrahlung generated by interaction with a diamond radiator will achieve a nominal 40% linear polarization and photon energies between 8.5 and 9 GeV from 12.1 GeV electrons, which are then tagged or diverted to a medium power 60kW electron dump. The expected photon flux is 107-108 Hz. This paper discusses the experimental line design, commissioning experience gained since first beam in spring 2014, and the present results of beam commissioning by the experiment. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA036  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPMA057 Commissioning of Active Interlock System for NSLS II Storage Ring storage-ring, synchrotron, radiation, synchrotron-radiation 1962
 
  • S. Seletskiy, C. Amundsen, J. Choi, J.H. De Long, K.M. Ha, C. Hetzel, H.-C. Hseuh, Y. Hu, P. Ilinski, S.L. Kramer, Y. Li, M.A. Maggipinto, J. Mead, D. Padrazo, T.V. Shaftan, G. Shen, O. Singh, R.M. Smith, W.H. Wahl, G.M. Wang, F.J. Willeke, L. Yang
    BNL, Upton, Long Island, New York, USA
  
  The NSLS-II storage ring is protected from possible damage from insertion devices (IDs) synchrotron radiation by a dedicated active interlock system (AIS). It monitors electron beam position and angle and triggers beam drop if beam orbit exceeds the boundaries of pre-calculated active interlock envelope. In this paper we describe functional details of the AIS and discuss our experience with commissioning of the AIS for the first six IDs installed in the storage ring.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA057  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTY006 Study of Electron Cloud Instabilities in FCC-hh electron, proton, emittance, simulation 2007
 
  • K. Ohmi
    KEK, Ibaraki, Japan
  • L. Mether, D. Schulte, F. Zimmermann
    CERN, Geneva, Switzerland
  
  Electron cloud effects are serious issue for LHC and future hadron colliders, FCC-hh. Electron cloud causes coherent instabilities due to collective motion between beam and electrons. Electron cloud also causes incoherent emittance growth due to nonlinear force of beam-cloud electron force. We discuss the fast head-tail instability and the emittance growth in FCC-hh.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY006  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTY016 Study of Background and MDI Design for CEPC background, detector, scattering, simulation 2028
 
  • Y. Yue, Q. Qin
    IHEP, Beijing, People's Republic of China
  
  CEPC is a project designed to obtain a large number of Higgs events by keeping e+e− collisions at the center-of-mass energy of 240 GeV and deliver peak luminosity above 1034 cm-2 s-1 for each interaction point. The super high energy and the pretty high luminosity will bring some special background problems, which will exert difficulty on the MDI design and the detectors protection. In this article, I will show the simulation result of the main background sources at CEPC and give some suggestions on the MDI design and detectors protection.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY016  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTY079 Initial Modeling of Electron Cloud Buildup in the Final-focus Quadrupole Magnets of the SuperKEKB Positron Ring electron, quadrupole, positron, vacuum 2218
 
  • J.A. Crittenden
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: US National Science Foundation contracts PHY-0734867, PHY-1002467, and PHY-1068662, US Department of Energy contract DE-FC02-08ER41538 and the Japan/US Cooperation Program
We present modeling results for electron cloud buildup in the final-focus quadrupole magnet nearest the interaction point in the SuperKEKB positron storage ring. The calculations employ as input recently obtained estimates of synchrotron radiation absorption rates on the vacuum chamber wall including the effect of photon scattering. While the effect both adds to and subtracts from photoelectron production at the points in the ring where unscattered photons strike the wall, it also produces cloud in the other regions. Results for beam-pipe-averaged and beam-averaged cloud densities are presented, as are estimates for the contribution to the fractional vertical coherent tune shift. The effect of the strong magnetic fields is studied and the dependence on the vacuum chamber surface secondary yield characteristics is considered. Cloud buildup is modeled with a 2D particle-in-cell macroparticle tracking code validated using recent measurements of electron trapping in a quadrupole magnet at the Cornell Electron Storage Ring Test Accelerator. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY079  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTY080 Synchrotron Radiation Analysis of the SuperKEKB Positron Storage Ring positron, scattering, electron, vacuum 2222
 
  • J.A. Crittenden, D. Sagan
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • T. Ishibashi, Y. Suetsugu
    KEK, Ibaraki, Japan
  
  Funding: US National Science Foundation contracts PHY-0734867, PHY-1002467, and PHY-1068662, US Department of Energy contract DE-FC02-08ER41538 and the Japan/US Cooperation Program.
We report on modeling results for synchrotron radiation absorption in the SuperKEKB positron storage ring vacuum chamber including the effects of photon scattering on the interior walls. A detailed model of the geometry of the inner vacuum chamber profile has been developed and used as input to a photon tracking code. Particular emphasis is placed on the photon absorption rates in the electron-positron interaction region. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY080  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPWI009 Development of Un-destructive Inspection System for Large Concrete Infrastructure by using Accelerator Based Compact Neutron Source neutron, detector, target, proton 2262
 
  • A. Taketani, H. Baba, T. Hashiguchi, G. Hu, Y. Ikeda, Q. Jia, H. Ota, Y. Otake, Y. Seki, S. Wang, Y. Yamagata, S. Yanagimachi
    RIKEN, Saitama, Japan
  • K. Hirota
    Nagoya University, Nagoya, Japan
  • K. Kino
    Hokkaido University, Sapporo, Japan
  • S. Tanaka
    KEK, Tsukuba, Japan
  
  Aged large concrete structure, such as highway, bridges and so on, need to be inspected in order to maintain with less cost by un-destructive method. We have been developing un-destructive inspection system by using fast neutron which can penetrate thick concrete. The system will be consisted of (1) Transportable Accelerator based Neutron Source, (2) Fast neutron imaging detector, and (3) Image processing for getting 3D image. RIKEN Accelerator based compact Neutron Source (RANS), which consists of 7MeV proton LINAC and target station, has been operating since 2013. RANS can generate thermal (~25meV) and fast (~2MeV) neutron. Fast neutron detector are developed with plastic scintillator and semiconductor photon sensors. It can see 10mm thick steel rod with 2mm accuracy through 300mm thick concrete.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI009  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPWI026 A Monochromatic Gamma Source without Neutrons neutron, proton, rfq, DTL 2292
 
  • R.W. Garnett, S.S. Kurennoy, L. Rybarcyk, T.N. Taddeucci
    LANL, Los Alamos, New Mexico, USA
  
  Funding: This work is supported by the U. S. Department of Energy Contract DE-AC52-06NA25396.
High-energy gamma rays can be efficiently produced using the direct excitation of the 15.1-MeV level in 12C via the (p, p’) reaction. This reaction has the threshold energy of 16.38 MeV. The threshold for neutron production via 12C (p, n) is 19.66 MeV, so there is an energy window of 3.28 MeV where the 15.1-MeV photons can be produced without any direct neutrons. Thick-target yield estimates indicate that just below the neutron production threshold, the photon output is about twice that of the more well-known 11B (d, n) reaction requiring 4-MeV deuterons, with the expected 15.1-MeV photon flux to be approximately 1011 s-1 sr-1 per 1 mA of 19.6-MeV proton current on a carbon target. A compact pulsed proton accelerator capable of 10-mA or greater peak currents to drive such a gamma source will be presented. The accelerator concept is based on a 4-rod RFQ followed by compact H-mode structures with PMQ focusing. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI026  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPJE002 Photoinjector Improvement and Control by Surface Acoustic Waves electron, experiment, controls, linac 2678
 
  • R.P. Johnson
    Muons, Inc, Illinois, USA
  • A. Afanasev, C.E. Korman
    GWU, Washington, USA
  
  A new technique is being developed to enhance the efficiency of photocathodes used for electron sources to improve emission capabilities of electron sources, such as bunch charge and average current. The proposed technique is based on the use of surface acoustical waves (SAW) generated on the piezoelectric surface of a GaAs photocathode. The generation of SAW on piezoelectric substrates is known to produce strong piezoelectric fields that propagate on the surface of the material. These fields can significantly suppress recombination effects and result in enhanced quantum efficiency of photoemission. Experimental measurements of photoemission quantum efficiency will be done on semiconductors used as photocathode materials (e.g., GaAs) in presence of SAW with varied parameters. The experimental results will be used as input for physics modeling that will provide a basis for design of operational SAW-enhanced photocathodes. While the improved quantum efficiency and parameter control expected from the use of SAW will be useful for many research devices and accelerators, the commercialization of such a widespread field as electron microscopy is compelling.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPJE002  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPMA045 Energy Deposition and DPA in the Superconducting Links for the HiLumi LHC project at the LHC Interaction Points neutron, luminosity, simulation, radiation 2865
 
  • F. Broggi, A. Bignami, C. Santini
    INFN/LASA, Segrate (MI), Italy
  • A. Ballarino, F. Cerutti, L.S. Esposito
    CERN, Geneva, Switzerland
  
  Funding: The work is part of HiLumi LHC Design Study, partly funded by the European Commission, GA 284404, and included in the High Luminosity LHC project.
In the framework of the upgrade of the LHC machine, the powering of the LHC magnets foresees the removal of the power converters and distribution feedboxes from the tunnel and its location at the surface[1]. The Magnesium Diboride (MgB2) connecting lines in the tunnel will be exposed to the debris from 7+7 TeV p-p interaction. The Superconducting (SC) Links will arrive from the surface to the tunnel near the separation dipole, at about 80 m from the Interaction Point at IP1 and IP5. The Connection Box (where the cables of the SC Links are connected to the NbTi bus bar) will be close to the beam pipe. The debris and its effect on the MgB2 SC links in the connection box (energy deposition and displacement per atom) are presented. The effect of thermal neutrons on the Boron consumption and the contribution of the lithium nucleus and the alpha particle on the DPA are evaluated. The results are normalized to an integrated luminosity of 3000 fb-1, value that represents the LHC High Luminosity lifetime. The dose delivered to the SC Links is found to be below the damage limit. Further studies are necessary to correlate the induced displacement per atom to the superconducting properties. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMA045  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPHA011 Photodesorption and Electron Yield Measurements of Thin Film Coatings for Future Accelerators vacuum, electron, experiment, solenoid 3123
 
  • R. Kersevan, M. Ady, P. Chiggiato
    CERN, Geneva, Switzerland
  • T. Honda, Y. Tanimoto
    KEK, Tsukuba, Japan
  
  The performance of future accelerators could be limited by electron cloud phenomena and high photodesorption yields. For such a reason, the study of secondary electron and photodesorption yields of vacuum materials is essential. The eradication or mitigation of both secondary electron and molecule desorption could strongly reduce the beam scrubbing time and increase the availability of nominal beams for experiments. Surface modifications with the desired characteristics can be achieved by thin-film coatings, in particular made of amorphous carbon and non-evaporable getters (NEG). In the framework of a new collaboration, several vacuum chambers have been produced, and different coatings on each of them have been applied. The samples were then irradiated at KEK’s Photon Factory with SR light of 4 keV critical energy during several days, allowing the measurement of the photodesorption yield as a function of the photon dose. This paper presents the experiment and briefly summarizes the preliminary photodesorption and photoelectron yield data of different coatings. The results can be used for future machine design with similar conditions, such as the FCC-hh.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPHA011  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPHA012 Synchrotron Radiation Distribution and Related Outgassing and Pressure Profiles for the HL-LHC Final Focus Magnets radiation, vacuum, synchrotron, synchrotron-radiation 3127
 
  • R. Kersevan
    CERN, Geneva, Switzerland
  
  The HL-LHC final focus area, from D2 to the interaction point, has been modelled based on the latest vacuum chamber geometry and orbits. The synchrotron radiation (SR) fans are computed using the Monte Carlo code SYNRAD+, in the dipole approximation regime. The angular and energy dependence of the reflectivity of the copper surfaces is considered, as well as the surface roughness. Once the SR distributions are computed, they are converted into outstanding profiles by using data available in literature. The test-particle Monte Carlo code Molflow+ is then used and the related pressure profiles and gas density distribution are computed. This allows an optimization of the pattern of the perforations on the tungsten-shielded beam screen proposed for this area. It is shown that the resultant gas density is below the limit dictated by the ATLAS and CMS detectors.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPHA012  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPHA019 Development and Production of Non-evaporable Getter Coatings for MAX IV cathode, electron, vacuum, cavity 3145
 
  • P. Costa Pinto, B. Bártová, B. Holliger, S. Marques Dos Santos, V. Nistor, A. Sapountzis, M. Taborelli, I. Wevers
    CERN, Geneva, Switzerland
  • J. Ahlbäck, E. Al-Dmour, M.J. Grabski, C. Pasquino
    MAX-lab, Lund, Sweden
  
  MAX IV is presently under construction at Lund, Sweden, and the first beam for the production of synchrotron radiation is expected to circulate in 2016. The whole set of 3-GeV ring beam pipes is coated with Ti-Zr-V Non Evaporable Getter (NEG) thin film in order to fulfil the average pressure requirement of 1x10-9 mbar, despite the compact magnet layout and the large aspect ratio of the vacuum chambers. In this work, we present the optimisations of the coating process performed at CERN to coat different geometries and mechanical assembling used for the MAX IV vacuum chambers; the morphology of the thin films is analysed by Scanning Electron Microscopy; the composition and thickness is measured by Energy Dispersive X-ray analysis; the activation of the NEG thin film is monitored by X-ray Photoemission Spectroscopy; the vacuum performance of the coated beam pipes is evaluated by the measurement of hydrogen sticking coefficient. The results of the coating production characterisation for the 84 units coated at CERN are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPHA019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPHA034 Commissioning of the De-ionized Water System for Taiwan Photon Source booster, controls, target, storage-ring 3188
 
  • W.S. Chan, J.-C. Chang, Y.C. Chang, C.S. Chen, Y.-C. Chung, C.W. Hsu, C.Y. Liu, Z.-D. Tsai
    NSRRC, Hsinchu, Taiwan
  
  The de-ionized water (DIW) system plays a critical role in removing waste heat from an accelerator machine. Through years of design and constructs, the DIW system for Taiwan Photon Source (TPS) was complete at the end of 2013, but it is important to confirm that the quantity and quality of DIW comply with the requirements of the accelerator machine. Testing, adjustment and balancing methods have been applied to verify that the DIW system for TPS can provide flow rates greater than 1659, 380, 1284 and 1238 GPM in the individual Cu, Al, RF and booster subsystems. The proposed system can supply DIW of quality such that the resistivity is greater than 10 MΩ-cm at 25±0.1 oC; the concentration of dissolved oxygen (DO) is less than 10 ppb.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPHA034  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPHA039 Inrush Current Suppression Scheme of Hot Swap Power Modules power-supply, controls, simulation, synchrotron 3200
 
  • Y.T. Li, C.Y. Liu, K.-B. Liu
    NSRRC, Hsinchu, Taiwan
  
  The corrected magnet power supplies apply modular designed for Taiwan Photon Source synchrotron project (TPS). If the module is damaged in the chassis, it must to be replaced without interrupting the power. However, the modular is a shared DC bus. If there is no good design and planning, it will cause the protection circuit into action. In this article the theoretical derivation and implementation are used to prove the feasibility and necessity of the soft-start circuit. In the actual signal measurements it could be clearly seen the inrush currents is refrained and improved. Finally, the soft-start circuit is implemented applications in correction magnet power supply modular of Taiwan Photon Source synchrotron project (TPS).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPHA039  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPHA046 Outgassing Analysis During Transport for 14m Long Arc-Cell Vacuum Chambers of the Taiwan Photon Source vacuum, ion, storage-ring, electron 3219
 
  • L.H. Wu, C.K. Chan, C.H. Chang, C.-C. Chang, S.W. Chang, Y.P. Chang, B.Y. Chen, J.-R. Chen, Z.W. Chen, C.M. Cheng, G.-Y. Hsiung, S-N. Hsu, H.P. Hsueh, C.S. Huang, Y.T. Huang, T.Y. Lee, I.C. Yang
    NSRRC, Hsinchu, Taiwan
  • J.-R. Chen
    National Tsing Hua University, Hsinchu, Taiwan
  
  An outgassing analysis during transportation for the large, 14-m-long, ultra-high-vacuum aluminum arc-cell chambers of the Taiwan Photon Source (TPS) was performed using residual gas analysis (RGA). Each cell was baked to 150 °C in the laboratory to achieve ultra-high vacuum. Under pumping by primarily ion pumps (IP) and non-evaporable getter (NEG) pumps, the cells obtained pressures of 6.4×10-9 Pa on average, and the main residual gas was H2. Here, vacuum pressure measurements and residual gas analyses were performed in situ while a cell chamber was being transported. It was found that the vibration of the arc-cell vacuum chamber caused the pressure to rise abruptly; in this case, the main outgassing gas was CH4. Once the arc cell had been fully installed, the vacuum pressure gradually decreased to the original vacuum pressure because of the pumping effect of the ion gauges.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPHA046  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPHA048 Behavior of Vacuum Pressure in TPS Vacuum System vacuum, storage-ring, booster, synchrotron 3222
 
  • I.C. Yang, C.K. Chan, C.-C. Chang, B.Y. Chen, J.-R. Chen, C.M. Cheng, J. -Y. Chuang, G.-Y. Hsiung, C.K. Kuan, C.C. Liang, I.C. Sheng, L.H. Wu
    NSRRC, Hsinchu, Taiwan
  
  Taiwan Photon source (TPS) is in its first stage commissioning in 2014-2015. The vacuum systems of TPS were installed for commissioning since August 2014. After four months performance testing and subsystem integration, the commissioning of booster ring began on 12 December and then the first 3 GeV beam was stored on 31 December. 100mA beam current, 35Ah accumulated beam dose was archived in March 2015 before machine shut down. The average pressure in storage ring is 2.8×10-8 Pa before commissioning, rising to 1.33×10-7 Pa with 100mA beam current. In 35Ah accumulated beam dose, the target of beam cleaning effect has reached to 8.92×10-10 Pa/mA. The vacuum performance, experience and events during commissioning will be presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPHA048  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPTY008 Superconducting Harmonic Cavity for the Advanced Photon Source Upgrade cavity, HOM, cryomodule, SRF 3267
 
  • M.P. Kelly, A. Barcikowski, J. Carwardine, Z.A. Conway, D. Horan, S.H. Kim, P.N. Ostroumov, G.J. Waldschmidt
    ANL, Argonne, Illinois, USA
  • J. Rathke, T. Schultheiss
    AES, Medford, New York, USA
  
  A new bunch lengthening cryomodule using a single-cell ‘higher-harmonic’ superconducting cavity (HHC) based on the TESLA shape and operating at the 4th harmonic (1408 MHz) of the main RF is under development at Argonne. The system will be used to improve the Touschek lifetime and increase the single-bunch current limit in the upgraded multibend achromat lattice of the Advanced Photon Source electron storage ring. The 4 K cryomodule will fit within one half of a straight section, ~2.5 meters, of the ring. The system will use a pair of moveable 20 kW (each) CW RF power couplers to adjust the loaded Q and extract power from the beam. This will provide the flexibility to adjust the impedance presented to the beam and run at various beam currents. Higher-order modes (HOMs) induced by the circulating electron beam will be extracted along the beam axis and damped using a pair of room temperature beam line absorbers. Engineering designs and the prototyping status for the cavity, power couplers and HOM absorbers are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY008  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWI013 New Results of Development on High Efficiency High Gradient Superconducting RF Cavities cavity, SRF, linac, niobium 3518
 
  • R.L. Geng
    JLab, Newport News, Virginia, USA
  • C. Adolphsen, Z. Li
    SLAC, Menlo Park, California, USA
  • J.K. Hao, K.X. Liu
    PKU, Beijing, People's Republic of China
  • H.Y. Zhao
    Ningxia Orient Tantalum Industry Co., Ltd., Dawukou District, Shizuishan city, People's Republic of China
  
  We report on the latest results of development on high efficiency high gradient superconducting radio frequency (SRF) cavities. Several 1-cell cavities made of large-grain niobium (Nb) were built, processed and tested. Two of these cavities are of the Low Surface Field (LSF) shape. Series of tests were carried out following controlled thermal cycling. Experiments toward zero-field cooling were carried out. The best experimentally achieved results are Eacc = 41 MV/m at Q0 = 6.5×1010 at 1.4 K by a 1-cell 1.3 GHz large-grain Nb TTF shape cavity and Eacc = 49 MV/m at Q0 = 1.5×1010 at 1.8 K by a 1-cell 1.5 GHz large-grain Nb CEBAF upgrade low-loss shape cavity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI013  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THYC1 Comparison of Beam Diagnostics for 3rd and 4th Generation Ring-based Light Sources diagnostics, feedback, emittance, electronics 3657
 
  • H. Maesaka
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  
  This talk will present the challenges and progress required in beam instrumentation for next generation storage-ring light sources. These light sources aim at small natural emittance of approximately 100 pm rad in order to achieve much higher brightness than the present 3rd generation light sources. This small emittance is realized by a multi-bend lattice, which has a small dynamic aperture of only several mm, a small beam size of approximately 10 microns, etc. Therefore, the beam orbit must be precisely measured by beam position monitors (BPM) for the orbit correction and the beam size should be monitored with less than 10-micron resolution in order to estimate the beam emittance. A bunch-by-bunch feedback system is also required for the suppression of various instabilities coming from narrow beam chamber. In addition, since the stable tune region is small, a real-time tune monitor is demanded for the tune correction. We introduce leading-edge instrumentation techniques to overcome these difficulties, comparing with of 3rd generation light sources.  
slides icon Slides THYC1 [3.690 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THYC1  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THYC2 Recent Trends in Beam Size Measurements using the Spatial Coherence of Visible Synchrotron Radiation synchrotron, optics, radiation, operation 3662
 
  • T.M. Mitsuhashi
    KEK, Ibaraki, Japan
  
  The optical method of measuring the transverse beam profile and size using visible synchrotron radiation (SR) began with simple imaging systems. The resolution was limited by both the diffraction and the wavefront error making it difficult to resolve beam sizes less than 50 μm. Instead of imaging, a method for measuring the beam profile and size using the spatial coherence was introduced. The method is based on Van Cittert-Zernike’s theorem, and can resolve 4-5 μm beam sizes with an error of only 0.5 μm. In this presentation, the principle of the measurement, the SR interferometer design, and some resent measurement results are reviewed. The incoherent field depth effect for the horizontal beam size measurement is also described with some results. Design study calculations for the SR interferometer at the LHC will be presented.  
slides icon Slides THYC2 [2.629 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THYC2  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)