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photon

Paper Title Other Keywords Page
MOPC028 Experimental Layout of 30 nm High Harmonic Laser Seeding at FLASH electron, undulator, radiation, laser 127
 
  • H. Schlarb, S. Düsterer, J. Feldhaus, T. Laarmann
    DESY, Hamburg
  • A. Azima, J. Boedewadt, H. Delsim-Hashemi, M. Drescher, S. Khan, Th. Maltezopoulos, V. Miltchev, M. Mittenzwey, J. Rossbach, R. Tarkeshian, M. Wieland
    Uni HH, Hamburg
  Since 2004, the free-electron laser FLASH at DESY has operated in the Self-Amplified Stimulated Emission mode, delivering to users photon beams with wavelengths between 6.5 nm and 40 nm. In 2009, DESY plans to install a 3.9 GHz RF acceleration section for the production of electron bunches with high peak currents (~kA), but ten times larger pulse durations (~250 fs) compared to the present configuration. The relaxed timing requirements of the new configuration make it possible to externally seed FLASH with high harmonics of an optical laser (sFLASH). The aim of the project is to study the technical feasibility of seeding an FEL at 30 nm with a stability suited for user operation. sFLASH will use 10 m of gap-tunable undulators installed in front of the fixed gap SASE-undulator. A chicane behind the seeding undulators will allow to extract the output radiation for a careful characterisation and for first pump-probe experiments with a resolution in the 10 fs range by combining FEL and seed laser pulses.  
 
MOPC040 COBALD - an Inverse Compton Back-scattering Source at Daresbury laser, electron, vacuum, beam-transport 160
 
  • D. J. Holder
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • D. Laundy
    STFC/DL, Daresbury, Warrington, Cheshire
  • G. Priebe
    STFC/DL/SRD, Daresbury, Warrington, Cheshire
  An inverse Compton Back-scattering (CBS) ultra-short pulsed x-ray source driven by the multi-terawatt laser installed at Daresbury’s Energy Recovery Linac Prototype (ERLP) is being developed. Hard x-rays, ranging from 15 keV to 30 keV, depending on the backscattering geometry, will be generated through the interaction of the laser pulse and an electron bunch delivered by ERLP. The X-rays created contain 15 ·106 photons per pulse from head-on collisions, with a pulse duration comparable to that of the incoming electron bunch, and 5 ·106 photons per pulse from side-on collisions, where the laser pulse defines the pulse width. The peak spectral brightness of ≈1020 photons/s/mm2/mrad2/0.1% ΔE/E is close to that of 4th-generation synchrotron light sources. Called COBALD, it will initially be used as a short pulse diagnostic for the ERLP electron beam and will explore the extreme challenges of photon/electron beam synchronization, which is a fundamental requirement for all accelerator-based (whether FEL or spontaneous SR) dynamics programmes. Furthermore, a fast-melting experiment will be used as a diagnostic tool to provide further information on the stability of the source.  
 
MOPC046 Femtoslicing at BESSY - Detecting More Photons laser, background, single-bunch, electron 172
 
  • T. Quast, K. Holldack
    BESSY GmbH, Berlin
  • S. Khan
    Uni HH, Hamburg
  • R. Mitzner
    Universität Muenster, Physikalisches Institut, Muenster
  The BESSY femtoslicing facility is now well established* and has proven its succesful operation for femtosecond laser-pump and x-ray-probe experiments**. However, many interesting physical phenomena cannot be addressed with the presently available comparably low number of photons detected at the sample. The most direct way to increase the photon flux is to increase the laser repetition rate. In order to preserve the excellent fs-signal to ps-background ratio special storage ring fill patterns and corresponding laser synchronisation schemes have been studied. We present calculations showing the influence of a dedicated new radiator promising better flux and polarisation properties. Recent results from a new beamline based on high transmission reflection zone plates will be presented. A new avalanche photo diode-array-based detection system has been successfully tested. This allows a parallel detection in the dispersion plane behind the monochomator. The status of these improvements will be presented.

*S. Khan et al. Phys. Rev. Lett, (97), 074801 (2006).
**C. Stamm et al. Nature Mater. 6, 740 (2007).

 
 
MOPC053 BEAM DYNAMICS IN THE LASER-ELECTRON STORAGE RING FOR A COMPTON X-RAY SOURCE laser, electron, scattering, lattice 187
 
  • P.-CH. Yu, W.-H. Huang, C.-X. Tang, Y. Wang
    TUB, Beijing
  We present the lattice analysis and simulation study of the beam dynamics in the pulse mode of the laser-electron storage ring. Compton Scattering (CS), Intra-beam Scattering (IBS) with non-Gaussian beam and Synchro-tron Radiation (SR) are taken into consideration. Emittance growth, energy spread and phase space of the electron beam, as well as spatial and temporal distribution of the scattered photon are studied in this paper.  
 
MOPC072 Photocathode Studies at FLASH cathode, vacuum, laser, electron 232
 
  • S. Lederer, S. Schreiber
    DESY, Hamburg
  • J. H. Han
    Diamond, Oxfordshire
  • P. M. Michelato, L. Monaco, C. Pagani, D. Sertore
    INFN/LASA, Segrate (MI)
  Since several years, the DESY photoinjectors at FLASH and PITZ use cesium telluride photocathodes. One concern of operating an electron source with these cathodes is the degradation of the quantum efficiency (QE), starting from about 10 % to below 0.5 % during operation. To further understand this behavior the QE is monitored routinely. In this paper recent results from photocathode studies at FLASH are presented.  
 
MOPC094 Irradiation Effects on the Physio-mechanical Properties of Super-alloys Characterized by Low Thermal Expansion proton, target, radiation, electron 283
 
  • N. Simos, H. G. Kirk
    BNL, Upton, Long Island, New York
  • K. T. McDonald
    PU, Princeton, New Jersey
  • N. V. Mokhov
    Fermilab, Batavia, Illinois
  In an effort to address the limitations on high power accelerator target performance prompted by the elevated dose levels and the associated irradiation damage, an experimental study has been undertaken to evaluate the potential applicability of super alloys characterized by low thermal expansion over certain thermal regimes. The intriguing properties associated with materials such as super-Invar and the “gum” metal (Ti-12Ta-9Nb-3V-6Zr-O) are observed in their un-irradiated state. Irradiations were performed using the 200 MeV protons of the BNL Linac and/or a neutron flux generated by the stopping of the primary 112 MeV protons upstream of the exposed super-alloys. The paper presents the post-irradiation analysis results which reveal interesting damage reversal by the super-invar and unexpected low threshold of radiation resistance by the “gum” metal.

Work performed under the auspices of the US DOE.

 
 
MOPD026 Radiological Hazards Assessment for the Beam Dump of High Intensity Deuteron Accelerators proton, ion 502
 
  • D. López, M. Garcia, A. Mayoral, F. Ogando, J. Sanz, P. Sauvan
    UNED, Madrid
  Several of the most important aspects with regards to the radiological potential hazards assessment in the beam dump of a high intensity deuteron accelerator are analyzed. Deuteron and neutron induced activation as well as neutron production for the beam dump cartridge, in order to select low activation materials; evaluation of the tritium production due to the implanted deuterium in the material and the presence of water in the cooling and local shielding systems, relevant for the associated radiotoxicity; estimation of gamma dose rate in beam-off phase in the vicinity of the cartridge, important issue for accessibility and maintenance works of the system. All these points are assessed both for normal operation and commissioning phase in the IFMIF-EVEDA accelerator prototype. Several materials are studied according to neutron production using transport codes (MCNPX and PHITS) and EAF2007 libraries. Activation calculations with ACAB code use irradiation fluxes obtained with MCNPX. Evaluation of tritium production due to implanted deuterium is calculated with SRIM-TMAP7 coupled code. Tritium in water is calculated by activation procedures. Gamma dose rate is computed with MCNPX.  
 
MOPP008 Design of the Photon Collimators for the ILC Positron Helical Undulator undulator, positron, vacuum, electron 565
 
  • A. Bungau
    UMAN, Manchester
  • I. R. Bailey, J. B. Dainton, K. M. Hock, L. J. Jenner, L. I. Malysheva
    Liverpool University, Science Faculty, Liverpool
  • E. Baynham, T. W. Bradshaw, F. S. Carr, J. Rochford
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon
  • A. J. Brummitt, A. J. Lintern
    STFC/RAL, Chilton, Didcot, Oxon
  • J. A. Clarke, O. B. Malyshev, N. C. Ryder, D. J. Scott
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • N. A. Collomb
    STFC/DL, Daresbury, Warrington, Cheshire
  • A. F. Hartin
    OXFORDphysics, Oxford, Oxon
  • S. Hesselbach, G. A. Moortgat-Pick
    Durham University, Durham
  • L. Zang
    Cockcroft Institute, Warrington, Cheshire
  A number of photon collimators are placed inside the helical undulator to protect the cold surfaces of the vacuum vessel from being hit by the photons and thus achieving the baseline pressure requirement. Computer simulations were run in order to determine the energy deposition and instantaneous temperature rise in these collimators and various material candidates were studied. This paper presents the status of the simulation.  
 
MOPP024 Depolarization and Beam-beam Effects at the Linear Collider polarization, positron, background, linear-collider 598
 
  • G. A. Moortgat-Pick, S. Hesselbach
    Durham University, Durham
  • I. R. Bailey, G. A. Moortgat-Pick, B. J.A. Shepherd
    Cockcroft Institute, Warrington, Cheshire
  • D. P. Barber
    DESY, Hamburg
  • E. Baynham, T. W. Bradshaw, F. S. Carr, J. Rochford
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon
  • A. J. Brummitt, A. J. Lintern
    STFC/RAL, Chilton, Didcot, Oxon
  • A. Bungau
    UMAN, Manchester
  • J. A. Clarke, O. B. Malyshev, N. C. Ryder, D. J. Scott
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • J. B. Dainton, K. M. Hock, L. J. Jenner, L. I. Malysheva, L. Zang
    Liverpool University, Science Faculty, Liverpool
  • A. F. Hartin
    OXFORDphysics, Oxford, Oxon
  The clean environment at the interaction point of a lepton linear collider allows high-precision measurements for physics analyses. In order to exploit this potential, precise knowledge about the polarization state of the beams is also required. In this paper we concentrate on depolarization effects caused by the intense beam-beam interaction, which is expected to be the dominant source of depolarization. Higher-order effects, as well as critical analyses of the theoretical assumptions used in the past and theoretical improvements in the derivation of suitable equations, are given. Updates on existing simulation programs are reported. Numerical results for the design of the International Linear Collider (ILC) are discussed.  
 
MOPP057 ILC DR Vacuum Design and E-cloud electron, vacuum, positron, dipole 673
 
  • O. B. Malyshev
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • W. Bruns
    WBFB, Berlin
  An electron cloud parameters and vacuum design are tightly bounded to each other. Input parameters for the e-cloud depend on shape of vacuum chamber and surface property (material, roughthness, coatings, etc.), electron multipacting in the vacuum chamber causes the electron stimulated gas desorption and may require modification of vacuum system to deal with it. This paper describes the e-cloud modelling performed in a way to optimise ILC DR vacuum design in positron ring and to have clear understanding what modification in vacuum chamber are required. Three parameters of e-cloud were varied in turn: photo-electron emission, secondary electron yield and gas pressure. It was found all three parameter should not exceed certain value to keep the e-cloud density to an acceptable level. The energy and intensity of electron bombardment of the vacuum chamber walls and electron stimulated gas desorption were also calculated. It was found that electron stimulated gas desorption is comparable or larger than the photon stimulated desorption and should be considered in vacuum design.  
 
MOPP069 A Prototype Target Wheel for the ILC Positron Source target, positron, undulator, simulation 706
 
  • I. R. Bailey, L. J. Jenner, C. J. Nelson
    Liverpool University, Science Faculty, Liverpool
  • I. R. Bailey
    Cockcroft Institute, Warrington, Cheshire
  • D. G. Clarke, K. P. Davies, A. Gallagher
    STFC/DL, Daresbury, Warrington, Cheshire
  • J. A. Clarke
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • J. Gronberg, L. B. Hagler, W. T. Piggott
    LLNL, Livermore, California
  In this paper we describe the design, construction and commissioning of a prototype based on the positron production target wheel planned for the ILC positron source. The efficiency of the current baseline positron source design for the ILC can be improved if the conversion target is partially immersed in the magnetic field of the capture optics, thereby increasing the overall capture efficiency for positrons by a factor of two or more. However, immersion of the rotating target wheel generates strong eddy currents leading to additional heating and stresses on the wheel. The primary purpose of our prototype, which had been assembled at Daresbury Laboratory, is to investigate the effects of eddy currents induced in a titanium alloy wheel moving with rim speeds up to 100 metres per second in magnetic fields of the order of 1 Tesla.  
 
MOPP070 Construction of a Full Scale Superconducting Undulator Module for the International Linear Collider Positron Source undulator, vacuum, positron, electron 709
 
  • J. A. Clarke, O. B. Malyshev, D. J. Scott, B. J.A. Shepherd
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • I. R. Bailey, J. B. Dainton, K. M. Hock, L. J. Jenner, L. I. Malysheva, L. Zang
    Liverpool University, Science Faculty, Liverpool
  • E. Baynham, T. W. Bradshaw, A. J. Brummitt, F. S. Carr, A. J. Lintern, J. Rochford
    STFC/RAL, Chilton, Didcot, Oxon
  • A. Bungau
    UMAN, Manchester
  • N. A. Collomb
    STFC/DL, Daresbury, Warrington, Cheshire
  • A. F. Hartin
    OXFORDphysics, Oxford, Oxon
  • S. Hesselbach, G. A. Moortgat-Pick
    Durham University, Durham
  • Y. Ivanyushenkov
    ANL, Argonne, Illinois
  • N. C. Ryder
    University of Bristol, Bristol
  The positron source for the ILC is dependent upon a >200m long undulator to generate a high flux of multi-MeV photons. The undulator system is broken down into a series of 4m cryomodules, which each contain two superconducting helical undulators. Following a dedicated R&D phase and the construction and measurement of a number of short prototypes a full scale cryomodule has now been completed for the first time. This paper reports on the design, manufacture, and test results of this cryomodule.  
 
MOPP072 A Study of Mechanical and Magnetic Issues for a Prototype Positron Source Target target, simulation, positron, undulator 715
 
  • L. J. Jenner, I. R. Bailey
    Cockcroft Institute, Warrington, Cheshire
  • D. G. Clarke, K. P. Davies, A. Gallagher
    STFC/DL, Daresbury, Warrington, Cheshire
  • J. A. Clarke
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • J. Gronberg, L. B. Hagler, W. T. Piggott
    LLNL, Livermore, California
  • S. Hesselbach
    Durham University, Durham
  • C. J. Nelson
    STFC/RAL, Chilton, Didcot, Oxon
  • J. Rochford
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon
  In order to construct a high yield, positron source that can meet the intensity requirements of future facilities, a robust conversion target is needed. One solution is to use a rotating titanium alloy wheel upon which a beam of photons is incident. The efficiency of capturing the resulting positrons can be optimised by immersing this system in a magnetic field. As described elsewhere*, a prototype of such a target has been built at Daresbury Laboratory, to investigate the mechanical challenges associated with its construction and to study the magnetic effects that the wheel will experience. In this paper, calibration of the instrumentation, the data acquisition system and the initial results from operating the wheel in a strong magnetic field are described. Such phenomena as the eddy current heating experienced by the wheel are measured and compared to results from modelling codes. Vibrational issues surrounding the wheel and supporting structure at various speeds are studied.

*ID: 3894 A Prototype Target Wheel for the ILC Positron Source

 
 
MOPP079 Studies on the Role of a Photon Collimator for the ILC Positron Source undulator, radiation, positron, simulation 733
 
  • L. Zang
    Cockcroft Institute, Warrington, Cheshire
  • I. R. Bailey, A. Wolski, L. Zang
    Liverpool University, Science Faculty, Liverpool
  Use of a helical undulator in the ILC positron source provides the possibility of producing a polarised positron beam. The degree of polarisation of the positrons depends upon the polarisation of the photons produced from the undulator, where the polarisation depends on the photon energy and production angle. We calculate these quantities for one design of the helical undulator for the ILC, investigate approximations commonly made in calculating the undulator photon spectrum and explore the role of of a photon collimator in determining the positron polarisation.  
 
MOPP106 Study of Radiation From RF Cavities electron, radiation, acceleration, background 805
 
  • R. Sandstrom
    DPNC, Genève
  • D. Huang
    IIT, Chicago, Illinois
  • J. Norem
    ANL, Argonne, Illinois
  Essential for muon accelerators such as neutrino factories or muon colliders, ionization cooling channels use RF cavities to restore the energy lost in liquid hydrogen absorbers. One major limitation in cooling comes from electrons emitted from the cavities which can cause breakdowns or unacceptable thermal load to the liquid hydrogen vessels. In the Muon Ionization Cooling Experiment MICE, these electrons also cause background in the detectors. This paper presents simulations related to these dark currents, and analysis of data from a direct measurement of this radiation in the MuCool Test Area (MTA).  
 
TUXM02 Performance and Trends of Storage Ring Light Sources emittance, storage-ring, brilliance, radiation 993
 
  • R. Bartolini
    Diamond, Oxfordshire
  We present an overview of the performance of the latest generation of operating storage ring light sources. Emphasis is given to the comparison of design parameters to the achieved performances. Trends and innovations of established light sources to meet the increasing user’s demand for high brightness and different time structures will be presented. Report on upgrades and improvements will be given including orbit stability, top-up, feedback systems, lower-ID gap operation and a review of the activities for the generation of ultra-short radiation pulses in storage rings.  
slides icon Slides  
 
TUOCM02 X-ray Monitor Based on Coded-aperture Imaging for KEKB Upgrade and ILC Damping Ring optics, damping, synchrotron, monitoring 1029
 
  • J. W. Flanagan, H. Fukuma, S. Hiramatsu, H. Ikeda, K.-I. Kanazawa, T. Mitsuhashi, J. Urakawa
    KEK, Ibaraki
  • J. P. Alexander
    CLASSE, Ithaca
  • M. A. Palmer
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • G. S. Varner
    UH, Honolulu, HI
  We present here design considerations for an x-ray monitor for high-resolution (a few um) and fast response (sub-nanosecond) for beam profile measurements to be used at an upgraded KEKB and/or ILC damping ring. The optics for the monitor are based on a technique borrowed from x-ray astronomy, coded-aperture imaging, which should permit broad-spectrum, low-distortion measurements to maximize the observable photon flux per bunch. Coupled with a high-speed digitizer system, the goal is to make sub-bunch-length, turn-by-turn measurements of beam profile and position.  
slides icon Slides  
 
TUPC007 Numerical and Experimental Investigation of the Contamination of X-ray Beam Position Monitors by Bending Magnet Edge Radiation radiation, dipole, undulator, synchrotron 1053
 
  • C. Bloomer, G. Rehm, C. A. Thomas
    Diamond, Oxfordshire
  The details of an investigation into bending magnet edge radiation at Diamond are discussed, reviewing the effects of this radiation on X-ray Beam Position Monitoring (XBPM) equipment. For some time it has been recognized that there are difficulties using XBPMs for determining the centre of mass position of an undulator beam due to contamination from bending magnet radiation. While the geometry of the XBPM blades is designed to help reduce background dipole interference, this radiation is known to account for approximately 1% of the signal received, skewing the calculated beam position by several micrometres. We made detailed models of the bending magnet edge radiation using the SRW program and used Matlab to analyse the data. We present this model and compare our prediction to experimental results obtained at Diamond.  
 
TUPC038 Filling Pattern Measurement for the Taiwan Light Source synchrotron, injection, controls, storage-ring 1137
 
  • C. Y. Wu, J. Chen, K. T. Hsu, K. H. Hu, C. H. Kuo
    NSRRC, Hsinchu
  Filling pattern will affect various operation performance of a synchrotron light source. Measurement of the filling pattern correctly is important. The dedicated filling pattern measurement system has been implemented in 2004 for multi-bunch operation in top-up operation mode. Measurement the purity of an isolated bunch by using time correlated single photon counting method is also addressed. Results are presented in this report.  
 
TUPC046 Study on Longitudinal Phase-space of High-brightness Electron Beams at ISIR, Osaka University electron, vacuum, linac, radiation 1161
 
  • R. Kato, T. Igo, G. Isoyama, S. Kashiwagi, M. Morio
    ISIR, Osaka
  The performance of the free-electron laser based on self-amplified spontaneous emission strongly depends on characteristics of the electron beam, such as its transverse, longitudinal, and energy profiles as well as bunch charge. The longitudinal phase-space for the electron beam consists of the longitudinal position and energy of electrons, and several methods are extensively under study to evaluate the phase-space profile of the electron beam. We are developing a measurement system consisting of a profile monitor, a bending magnet and a streak camera. We first considered an optical transition radiation monitor as the profile monitor, but we could not get the efficient number of photons to obtain the phase-space images since the angular distribution of the transition radiation is too large to concentrate in the electron energy region of 10 – 20 MeV. In order to increase the number of photons, we have changed to a Cherenkov radiator using a hydrophobic silica aerogel. The Cherenkov radiator was installed in the beam transport line from the linac to the FEL system. We will present an outline of the phase-space measurement system and preliminary experimental results.  
 
TUPC054 Pulse-by-pulse Photon Beam Monitor with Microstripline Structure in NSRRC storage-ring, synchrotron, synchrotron-radiation, impedance 1176
 
  • C. K. Kuan, C. L. Chen, J.-R. Chen, G.-Y. Hsiung, I. C. Sheng, Z.-D. Tsai, D.-J. Wang
    NSRRC, Hsinchu
  • H. Aoyagi, H. Kitamura, S. Takahashi
    JASRI/SPring-8, Hyogo-ken
  In order to diagnostic pulse-by-pulse beam movement of photon beam, NSRRC(Taiwan) and SPring-8 (Japan) have worked together to develop a front end beam monitor with microstripline structure, which is designed to have specific impedance of 50 ohm. The detector head is composed of a metal line (copper), ceramic plates (aluminum nitride) and a cooling base (copper tungsten). The metal line functions as a photocathode. The metal line is directly connected to SMA feed-through connectors to have fast response time. The detector head has been fabricated in SPring-8, and mounted on the monitor chamber and installed in NSRRC Superconducting Wiggler (SW) front end. The beam monitor can be used to examine not only pulse-by-pulse photon beam, but also the storage ring intensity and the pulse timing. Unique feature of the monitor is to produce unipolar short pulses. The design, fabrication and the measurement will be presented in this paper.  
 
TUPC060 A Counting Module for an Advanced Ionization Profile Monitor controls, background, synchrotron, extraction 1194
 
  • D. A. Liakin, S. V. Barabin, A. Y. Orlov
    ITEP, Moscow
  • P. Forck, T. Giacomini
    GSI, Darmstadt
  A new multi-channel counting module has been developed for advanced Ionization Profile Monitor applications. The module's maximal performance concerning time resolution is about 10 beam profile measurements per microsecond at the cost of a slightly reduced spatial resolution with 80% accuracy (or better). Module architecture, basic modes of operation and the user interface are discussed. The results of the first test in laboratory and first beam profile measurements are also presented.  
 
TUPC064 Design and Commissioning of a Quadrant BPM for the LNLS Beamlines vacuum, shielding, synchrotron, instrumentation 1200
 
  • S. R. Marques, F. H. Cardoso, C. Grizolli, L. Sanfelici, M. M. Xavier
    LNLS, Campinas
  We have recently designed and installed the first quadrant beam position monitor in the MX2 beamline. The whole monitor, including its electronics, was installed in vacuum to reduce errors from current leakage and noise coupled outside the vacuum chamber. Aspects of the mechanical and electronic design of this fluorescence-based beam position monitor, as well as the commissioning results are presented.  
 
TUPC067 Development of the Methods of Beam Energy Spread Determination in the VEPP-4M Collider collider, diagnostics, simulation, electron 1209
 
  • O. I. Meshkov, V. A. Kiselev, N. Yu. Muchnoi, S. V. Sinyatkin, V. V. Smaluk, V. N. Zhilich, A. N. Zhuravlev
    BINP SB RAS, Novosibirsk
  The nearest experimental program of the VEPP-4M electron-positron collider and the KEDR detector includes a scan of the energy area below J/psi meson to search narrow resonances. The monitoring of beam energy spread is important for that. In this report we discuss the application of several diagnostics for beam energy spread measurement. The data obtained with Compton Back-Scattering (CBS) technique are compared with the value of the spread derived from the betatron motion of the beam. Similar experiments were carried out before. They demonstrated the necessity to improve the algorithm of beam energy spread derivation using CBS technique. New set of experiments was aimed on the examination of the improved algorithm. The measurements by all the methods were done at the same accelerator run, i.e., the different diagnostics are compared directly. The value of the energy spread was determined for a fixed collider energy E= 1855 MeV. The beam energy spread was changed by the wiggler current variation.  
 
TUPC074 Beam Transverse Size Effects on the Transition Radiation Energy Spectrum electron, radiation, diagnostics, luminosity 1221
 
  • G. L. Orlandi
    ENEA C. R. Frascati, Frascati (Roma)
  A theoretical model for the transition radiation emission by a relativistic electron bunch is here presented. Such a model, based on an extension of the virtual quanta method to the case of high density charged beams, predicts the existence of beam transverse size effects on the short wavelength part of the transition radiation energy spectrum. The relevance of such effects to the transition radiation based beam diagnostics of an electron linear accelerator is discussed. The physical consistency of the proposed theoretical model for the transition radiation emission is demonstrated on the basis of the constraints imposed by the temporal causality and Huygens-Fresnel principles. Further arguments in favour of such a thesis, which concern the relativistic nature of the radiative mechanism, are discussed. A possible experiment, devoted to a crosscheck of the theoretical results in an electron linear accelerator, is also proposed.  
 
TUPC090 Ionisation Profile Monitor to Determine Spatial and Angular Stability of FEL Radiation of FLASH laser, ion, simulation, electron 1266
 
  • M. Sachwitz, A. Hofmann, S. Pauliuk
    DESY Zeuthen, Zeuthen
  • K. I. Tiedtke, H. Wabnitz
    DESY, Hamburg
  An Ionization Profile Monitor (IPM) is used to detect lateral position changes of an FEL beam. By its help, beam position stability can be measured via the parasitic ionization of the residual gas in the beamline. We give an outline on operation, calibration and maintenance of the two IPM that have been developed at DESY Zeuthen and that have recently been built into FLASH at DESY Hamburg.  
 
TUPD007 The Design and Fabrication of the Kicker Power Supply for TPS Project kicker, injection, storage-ring, power-supply 1446
 
  • C.-S. Fann, K. T. Hsu, S. Y. Hsu, K.-K. Lin, K.-B. Liu, Y.-C. Liu, C. Y. Wu
    NSRRC, Hsinchu
  The preliminary test results of the kicker power supply for TPS (Taiwan Photon Source) project will be presented in this report. The achieved capability of this test unit demonstrates that it fulfills the design requirement of providing half-sine pulsed current of 2.5 kA (peak), 5.2 s (base-width), with jitter < 1 ns (peak-to-peak). Both units of using thyratron and IGBT switches are built with the same requirements. The technical considerations of both units for this particular application will be discussed.  
 
TUPD036 G4Beamline Simulations for Detector Development simulation, electron, radiation, electromagnetic-fields 1506
 
  • T. J. Roberts, K. B. Beard
    Muons, Inc, Batavia
  In current research programs to develop radiation detection instruments, simplifying assumptions are frequently made in estimating the resolutions and efficiencies attainable by neutron and gamma-ray instruments. Monte Carlo programs (such as Geant4) are capable of realistically modeling such problems, but the technical details of setting up, running, and interpreting the required simulations are beyond the ability of all but the most expert researchers. G4beamline, a program that is an interface to the Geant4 toolkit for the simulation of accelerator beam lines, is being extended to model detectors and related systems needed for applications related to nuclear nonproliferation and other users. The program is flexible, extremely user friendly, and requires no programming by users. Simulations of simple or complex detectors can be setup quickly and are accurately simulated using the power and accuracy of Geant4 for the transport of particles, including scattering, attenuation, interactions, and decays.  
 
TUPP112 The RADIOTHOMX Project electron, laser, linac, gun 1785
 
  • C. Bruni, F. Couchot, Y. Fedala, J. Haissinski, M. Lacroix, R. Roux, V. Variola, Z. F. Zomer
    LAL, Orsay
  • N. Artemiev
    LOA, Palaiseau
  • Ph. Balcou, E. Cormier, S. Montant, M. C. Nadeau
    CELIA, Talence
  • JP. Brasile, A. S. Chauchat, C. Simonboisson
    THALES, Colombes
  • R. Czarny
    Thales Laser SA, Orsay
  • P. Gladkikh
    NSC/KIPT, Kharkov
  The goal of this project is to develop a compact device, which could produce an intense flux of monochromatic X-rays for medical applications. It is based on Compton back-scattering resulting from collisions between laser pulses and relativistic electron bunches. Intense laser beams can be obtained with a high gain Fabry-Perot cavity coupled with a high average power fiber laser. Such a scheme is going to be developed by CELIA and LAL laboratories. The accelerator design to produce high repetition rate electron bunches at 50 MeV is under study. Two possibilities are being investigated: either a linear accelerator combined with a storage ring operating at an injection frequency high enough to preserve the electron beam characteristics or a high average current ERL. Both accelerator configurations aiming at producing X-ray fluxes higher than 1012 photons/s will be presented.  
 
TUPP117 Review of Energy Variation Approaches in Medical Accelerators linac, electron, coupling, radiation 1797
 
  • S. M. Hanna
    MINA, Danville, California
  Most of cancer Radiation Therapy (RT) machines rely on a linac as the source of the treatment beam which can be an electron beam or an X-ray beam. In either case, an approach to vary the energy of the linac’s output beam may be needed to target cancer tumors of different depths. Over the last two decades, multiple approaches for medical linac energy variation were proposed and some of them have been developed and implemented clinically. The most direct and conventional technique is to vary the amount of the RF power delivered to the linac and hence the energy output as required by the treatment plan. A second approach involves keeping the RF power delivered to the linac fixed but varying the power delivered to different sections of the linac by utilizing a mechanical or an electronic switch that controls the power distribution inside the linac. A third approach is to use two separate linac sections. The first section receives a fixed amount of RF power while the RF power delivered to second section is controlled using conventional microwave power splitting techniques. In this paper we will review the above approaches and discuss the advantages and disadvantage of each technique.  
 
TUPP156 Development of a Compact X-ray Source Based on Laser-Compton Scattering with a Pulsed-laser Super-cavity laser, electron, target, scattering 1872
 
  • K. Sakaue, M. Washio
    RISE, Tokyo
  • S. Araki, M. K. Fukuda, Y. Higashi, Y. Honda, T. Taniguchi, N. Terunuma, J. Urakawa
    KEK, Ibaraki
  • N. Sasao
    Kyoto University, Kyoto
  A compact and high quality x-ray source is required for various fields, such as medical diagnosis, drug manifacturing and biological sciences. Laser-Compton based x-ray source that consists of a compact electron storage ring and a pulsed-laser super-cavity is one of the solutions of a compact x-ray source. Pulsed-laser super-cavity has been developed at KEK-ATF for a compact high brightness x-ray source. The pulsed-laser super-cavity enables to make high peak power and small waist laser at the collision point with the electron beam. Recently, 357MHz mode-locked Nd:VAN laser pulses can be stacked stably in a 420mm long Fabry-Perot cavity with 2.5kW average power in our R&D. On the other hand, we have succeeded to stack the pulsed amplified laser in the super-cavity. This indicates that the number of X-ray is multiplied due to the gain in the amplification system to synchronize the pulsed pump to the beam. In view of this successful result, we have started an X-ray generation experiment using a super-cavity and a multi-bunch electron beam at KEK-LUCX. Development of the super-cavity and the results of X-ray generation experiment will be presented at the conference.  
 
TUPP159 Dual Energy Material Recognition: Preliminary Results Obtained with the Radio-tomographic System Hosted in Messina simulation, electron, linac, target 1881
 
  • D. Loria, L. Auditore, R. C. Barnà, U. Emanuele, E. Morgana, A. Trifirò, M. Trimarchi
    INFN - Gruppo Messina, S. Agata, Messina
  • M. Carpinelli
    INFN-Cagliari, Monserrato (Cagliari)
  • A. Franconieri, M. Gambaccini
    INFN-Ferrara, Ferrara
  Dual Energy technique is a very powerful tool for material recognition. It typically involves X-ray energy below 1 MeV, thus limiting to few mm the thickness of the inspected heavy materials. However, it would be interesting to investigate the chance to extend this technique to higher energies, to allow recognition of thick heavy samples too. Encouraging preliminary tests performed by means of the radio-tomographic system based on a 5 MeV electron linac have suggested to develop a dual energy technique for high energy x-ray beams. This can be done because first experimental tests have confirmed the chance to vary the electron beam energy in a continuous way. As a consequence, bremsstrahlung beams with different end points can be produced, thus allowing to work with different x-ray transmissions. The composition of two different energies X-ray transmission results, allows to perform material recognition. By means of the MCNP4C2 code, simulations have been performed to evaluate the theoretical x-ray transmission in different materials and thickness. These results allow us to choose two x-ray energies providing the best results in order to perform material recognition.  
 
TUPP162 High Heat Load Components in TPS Front Ends synchrotron, undulator, radiation, synchrotron-radiation 1890
 
  • A. Sheng, J.-R. Chen, C. K. Kuan, Z.-D. Tsai
    NSRRC, Hsinchu
  National Synchrotron Radiation Research Center (NSRRC) will build a new synchrotron accelerator (TPS, Taiwan Photon Source) with a great heat-load power. Various IDs have been proposed. For instance, at 3.3 GeV, 350 mA, superconductivity wiggler SW4.8 may generate 5.8mrad wide, 57 kW/mrad2 power whereas undulator CU1.8 will be 0.7 mrad, 148 kW/mrad2. The function of the fixed mask in TPS front ends not only to protect the downstream vacuum from being hit by the radiation during miss-steering, but also shadow the unwanted power. More than one fixed masks are introduced in some high heat load front ends. High conductivity, high thermomechaical strength GlidCop® is used; design and thermomechanical analysis is also presented in this paper.  
 
WEOBG03 The Design of the Positron Source for the International Linear Collider positron, target, undulator, electron 1915
 
  • J. A. Clarke, O. B. Malyshev, D. J. Scott
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • I. R. Bailey, J. B. Dainton, K. M. Hock, L. J. Jenner, L. I. Malysheva, L. Zang
    Liverpool University, Science Faculty, Liverpool
  • E. Baynham, T. W. Bradshaw, A. J. Brummitt, F. S. Carr, A. J. Lintern, J. Rochford
    STFC/RAL, Chilton, Didcot, Oxon
  • V. Bharadwaj, J. Sheppard
    SLAC, Menlo Park, California
  • A. Bungau
    UMAN, Manchester
  • N. A. Collomb
    STFC/DL, Daresbury, Warrington, Cheshire
  • R. Dollan
    Humboldt Universität zu Berlin, Berlin
  • W. Gai, Y. Ivanyushenkov, W. Liu
    ANL, Argonne, Illinois
  • J. Gronberg, W. T. Piggott
    LLNL, Livermore, California
  • A. F. Hartin
    OXFORDphysics, Oxford, Oxon
  • S. Hesselbach, G. A. Moortgat-Pick
    Durham University, Durham
  • K. Laihem, S. Riemann, A. Schaelicke, A. Ushakov
    DESY Zeuthen, Zeuthen
  • T. Lohse
    Humboldt University Berlin, Institut für Physik, Berlin
  • A. A. Mikhailichenko
    Cornell University, Department of Physics, Ithaca, New York
  • N. C. Ryder
    University of Bristol, Bristol
  The high luminosity requirements and the option of a polarized positron beam present a great challenge for the positron source of a future linear collider. This paper provides a comprehensive overview of the latest proposed design for the baseline positron source of the International Linear Collider. We report on recent progress and results concerning the main components of the source: including the undulator, collimators, capture optics, and target.  
slides icon Slides  
 
WEXM01 Overview of VUV and Soft X-Ray FELs Worldwide brilliance 1938
 
  • R. J. Bakker
    PSI, Villigen
  A comprehensive overview of the status of FEL projects worldwide providing photons in the VUV to soft X-ray region. The paper should give an update of projects, the technolgies proposed and methods for stable high brilliance user beams. Seeding schemes should be discussed along with critical issues for reaching the shorter wavelengths.

1st priority

 
slides icon Slides  
 
WEPC016 Operation Status and Performances Upgrade on SOLEIL Storage Ring undulator, feedback, vacuum, insertion 2022
 
  • J.-M. Filhol, J. C. Besson, F. Bouvet, P. Brunelle, L. Cassinari, M.-E. Couprie, J.-C. Denard, C. Herbeaux, J.-F. Lamarre, J.-P. Lavieville, P. Lebasque, M.-P. Level, A. Loulergue, P. Marchand, A. Nadji, L. S. Nadolski, R. Nagaoka, M.-A. Tordeux
    SOLEIL, Gif-sur-Yvette
  SOLEIL is the French 2.75 GeV third generation synchrotron light source delivering beam to users since January 2007. Beginning of 2008 up to 13 beam-lines are taking beam, 7 from insertion devices (IDs), 2 from IR ports, and 4 from dipole ports, and 6 of them are open to external Users. Users have a full control of their IDs. With a 300 mA stored beam current in multi-bunch filling pattern, and position stability in the few micron range, the main target performances have been reached. A beam of 50 mA in 8 bunches was delivered to users for the first time in December 2007 for time structure experiments. Operation and performance status will first be given, namely subsystem behaviour (RF, vacuum, …), beam optics, orbit stability, beam lifetime, and operation statistics. Then the main objectives for 2008 will be reviewed: delivery of 4000 hours of user beam time, installation and commissioning of a second cryomodule for reaching the 500 mA current target, construction and installation of 6 new IDs leading to a total number of 17, improvement of the orbit stability with a fast orbit feedback complementary to the slow orbit one, and preparation for top-up operation.  
 
WEPC017 Short X-ray Pulse Generation in Taiwan Photon Source Using Deflecting Cavity electron, emittance, lattice, radiation 2025
 
  • H. Ghasem
    IPM, Tehran
  • G.-H. Luo
    NSRRC, Hsinchu
  We have purposed to use deflecting cavity for short X-ray pulses production in 3 GeV Taiwan Photon Source (TPS). Typical electron bunch length in TPS for 1.1MV RF gap voltage is about 5.7mm. Deflecting cavity generates correlation between longitudinal position and vertical momentum of particles in a bunch. Vertical kick of particle separates the photons that emit from ID vertically. Slit and asymmetric crystal in TPS beam line are used to compress the photon pulse duration. For a 60 m beam line of TPS, the operating of deflecting cavity up to 6MV voltage and eighth harmonic yields an FWHM pulse duration of radiated X-ray of about 0.48 ps for users.  
 
WEPC023 Ideas for a Future PEP Light Source brightness, undulator, emittance, storage-ring 2031
 
  • R. O. Hettel, K. L.F. Bane, L. D. Bentson, K. J. Bertsche, S. M. Brennan, Y. Cai, A. Chao, S. DeBarger, V. A. Dolgashev, X. Huang, Z. Huang, D. Kharakh, Y. Nosochkov, T. Rabedeau, J. A. Safranek, J. Seeman, J. Stohr, G. V. Stupakov, S. G. Tantawi, L. Wang, M.-H. Wang, U. Wienands
    SLAC, Menlo Park, California
  • I. Lindau
    Stanford University, Stanford, Califormia
  • C. Pellegrini
    UCLA, Los Angeles, California
  With the termination of operation of the PEP-II storage rings for high energy physics at hand, and with the migration of accelerator operation at SLAC in general to photon science applications, a study of the potential conversion of the PEP-II to a future light source has been initiated. With a circumference of 2.2 km and the capability for high current operation, it is clear that operating a converted ring at medium energy (3-6 GeV) could offer very low emittance and an average brightness of order 1022, limited primarily by the power handling capacity of photon beam line optical components. Higher brightness in the soft X-ray regime might be reached with partial lasing in long undulators if the emittance is sufficiently low, and high peak brightness could be reached with seeded FEL emission. Advanced pulsed rf technology might be used to generate short bunches and fast switched polarization in soft X-ray rf undulators. An overview of the preliminary findings of the PEP Light Source study group will be presented, including lattice, X-ray source and beam line options.  
 
WEPC032 Absolute Measurement of the MLS Storage Ring Parameters electron, storage-ring, radiation, induction 2055
 
  • R. Klein, G. Brandt, R. Fliegauf, A. Hoehl, R. Müller, R. Thornagel, G. Ulm
    PTB, Berlin
  • M. Abo-Bakr, K. B. Buerkmann-Gehrlein, J. Feikes, M. V. Hartrott, K. Holldack, J. Rahn, G. Wuestefeld
    BESSY GmbH, Berlin
  The Metrology Light Source (MLS), the new electron storage ring of the Physikalisch-Technische Bundesanstalt (PTB) located next to BESSY II in Berlin - Adlershof is dedicated to metrology and technology development in the UV and EUV spectral range as well as in the IR and THz region. The MLS can be operated at various electron beam energies up to approx. 600 MeV and at electron beam currents varying from 1 pA (one stored electron) up to 200 mA and is optimized for the generation of coherent synchrotron radiation. Of special interest for PTB is the operation of the MLS as a primary radiation source standard from the visible up to the X-ray region. Therefore the MLS is equipped with all the instrumentation necessary to measure the storage ring parameters needed for the calculation of the spectral photon flux according to the Schwinger theory with low uncertainty. The instrumentation and measurement results for the determination of the storage ring parameters are presented.  
 
WEPC034 Present Status of Siam Photon Source storage-ring, undulator, injection, synchrotron 2061
 
  • P. Klysubun, S. Cheedket, G. G. Hoyes, M. Oyamada, W. Pairsuwan, S. Rugmai, P. Sudmuang
    NSRC, Nakhon Ratchasima
  The Siam Photon Source (SPS) is a 1.2 GeV synchrotron light source situated in Nakhon Ratchasima, Thailand. It is currently in the fourth year of routine operation for synchrotron radiation users. In order to address the increasing user demand for increasing beamtime, better beam position stability, and improved machine reliability, several machine improvements and upgrades have been undertaken during the past year. This report first briefly gives the overview and important parameters of the light source, and then describes the current operation status and operation statistics in 2007. Recent machine improvements, for instance, modernization of injector components, improvement of vacuum system, recalibration of beam position monitors, and orbit correction, are presented together with the initial synopsis of the successful installation of the first insertion device, a permanent magnet planar undulator.  
 
WEPC035 Present Status of PF-ring and PF-AR in KEK injection, undulator, insertion, insertion-device 2064
 
  • Y. Kobayashi, S. Asaoka, K. Ebihara, K. Haga, K. Harada, T. Honda, T. Ieiri, M. Izawa, T. Kageyama, T. Kasuga, M. Kikuchi, K. Kudo, H. Maezawa, K. Marutsuka, A. Mishina, T. Mitsuhashi, T. Miyajima, H. Miyauchi, S. Nagahashi, T. T. Nakamura, T. Nogami, T. Obina, K. Oide, M. Ono, T. Ozaki, C. O. Pak, H. Sakai, Y. Sakamoto, S. Sakanaka, H. Sasaki, Y. Sato, M. Shimada, T. Shioya, M. Tadano, T. Tahara, T. Takahashi, S. Takasaki, Y. Tanimoto, M. Tejima, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, S. Yamamoto, Ma. Yoshida, M. Yoshimoto
    KEK, Ibaraki
  In KEK, we have two synchrotron light sources which were constructed in the early 1980s. One is the Photon Factory storage ring (PF-ring) and the other is the Photon Factory advanced ring (PF-AR). The PF-ring is usually operated at 2.5 GeV and sometimes ramped up to 3.0 GeV to provide photons with the energy from VUV to hard X-ray region. The PF-AR is mostly operated in a single-bunch mode of 6.5GeV to provide pulsed hard X-rays. Operational performances of them have been upgraded through several reinforcements. After the reconstruction of the straight section of the PF-ring in 2005, two short-period-gap undulators have been stably operated. They allow us to produce higher brilliant hard X-rays even at the energy of 2.5 GeV. In March 2008, the circular polarized undulator will be installed in the long straight section of 8.9 m. In the PF-AR, new tandem undulators have been operated since September 2006 to generate much stronger pulsed hard X-rays for the sub-ns resolved X-ray diffraction experiments. In this conference, we report present status of the PF-ring and the PF-AR.  
 
WEPC058 Operational Performance of the Taiwan Light Source feedback, injection, synchrotron, synchrotron-radiation 2124
 
  • Ch. Wang, H.-P. Chang, J.-C. Chang, J.-R. Chen, F.-T. Chung, F. Z. Hsiao, G.-Y. Hsiung, K. T. Hsu, C. K. Kuan, C.-C. Kuo, K. S. Liang, K.-K. Lin, Y.-H. Lin, K.-B. Liu, Y.-C. Liu, G.-H. Luo, R. J. Sheu, D.-J. Wang, M.-S. Yeh
    NSRRC, Hsinchu
  The Taiwan light source (TLS) is a 1.5 GeV third generation light source at the National Synchrotron Radiation Research Center (NSRRC) in Taiwan. It has been routinely operated since its opening in 1993. Several major machine upgrade projects have been undertaken and successfully completed in last 5 years, including implementing of digital bunch-by-bunch feedbacks, superconducting accelerating RF cavity, top-up mode injection, etc. The light source now moves forward to its era of mature operation. It delivers more than 5000 hours user time in 2007 with an up-time of more than 98% and a mean time between failures better than 80 hours. Here, we review its annual operational performance with detailed statistics and discuss the possible improvement directions of machine performance.  
 
WEPC099 A Superconductive Undulator for the Munich Laser-plasma Accelerator undulator, electron, radiation, brilliance 2228
 
  • P. Peiffer, T. Baumbach, A. Bernhard, D. Wollmann
    University of Karlsruhe, Karlsruhe
  • F. J. Gruener, D. Habs, C. Huebsch, R. Weingartner
    LMU, München
  • R. Rossmanith
    FZK, Karlsruhe
  Laser-plasma accelerators are expected to produce electron beams with bunch charges in the nano-Coulomb range with energies in the GeV range. By employing short-period superconductive undulators this may be utilized for the generation of undulator radiation in the X-ray regime with a compact laboratory-sized set up. In this contribution we report on the project of testing this concept at the Laser-Plasma Accelerator in Munich. A particular aim of this project is to push the superconductive undulator technology to shortest periods and highest on-axis fields at gap widths sufficiently large to reduce the impact of resistive wall wake fields on the electron beam. This might open a path to the generation of coherent radiation via the SASE process.  
 
WEPC100 Superconducting Insertion Devices with Variable Period Length undulator, wiggler, brilliance, insertion 2231
 
  • A. Bernhard, T. Baumbach, P. Peiffer, D. Wollmann
    University of Karlsruhe, Karlsruhe
  • R. Rossmanith
    FZK, Karlsruhe
  The tuning range and functionality of superconducting insertion devices may be significantly enhanced by period length switching. Period length switching can be achieved by employing two or more individually powerable subsets of superconducting coils in such a way that a current reversal in a part of these coil sets results in a period length variation. In this paper the opportunities and restrictions of period length switching in superconducting undulators are discussed from a general point of view. As a particular example, the design of a hybrid superconducting undulator/wiggler (SCUW) for ANKA based upon the period length switching technique is presented.  
 
WEPC119 First Year's Experience of Diamond Insertion Devices injection, undulator, wiggler, insertion 2285
 
  • E. C. Longhi, R. T. Fielder, I. P.S. Martin, J. C. Schouten, B. Singh
    Diamond, Oxfordshire
  • R. Bartolini
    JAI, Oxford
  Diamond was commissioned at 3GeV with seven insertion devices (IDs) already installed. The phase 1 IDs include five in-vacuum permanent magnet undulators, an APPLE–2 variable polarization device, and a superconducting wiggler. Since initial commissioning of the ring, three more in-vacuum undulators have been installed, and another three devices will be installed in the coming year. In this paper, we describe commissioning, characterizing, and operating with these IDs.  
 
WEPC120 An In Vacuum Wiggler WSV50 for Producing Hard X-rays at SOLEIL wiggler, vacuum, insertion, insertion-device 2288
 
  • O. Marcouillé, P. Brunelle, O. V. Chubar, M.-E. Couprie, J.-M. Filhol, C. Herbeaux, J. L. Marlats, A. Mary, K. Tavakoli
    SOLEIL, Gif-sur-Yvette
  SOLEIL is a medium energy storage ring (2.75 GeV) operating since 2006. The production of intense high energy photon beams requires insertion devices with high magnetic field and large number of periods. To cover the 20 keV-50 keV Photon Energy range, an in vacuum wiggler has been preferred to a superconducting wiggler. This choice results from a compromise between photon flux, investment and running cost. Deep studies have been performed to find the optimum magnetic field and period producing the maximum flux in the dedicated spectral range (20-50 keV). The wiggler is composed of 38 periods of 50 mm producing a 2.1 T magnetic field at a minimum gap of 5.5 mm. To minimize the high magnetic forces acting between the magnet arrays (10 tons), two compensation systems, composed of either springs or magnet blocks, have been designed. This paper presents the spectral performances of the wiggler compared with an optimized superconducting wiggler, the mechanical and magnetic design of the wiggler and the first tests of the compensation system.  
 
WEPC135 A New Concept for Reducing Phase Errors in Superconductive Undulators: Induction-shimming undulator, permanent-magnet, electron, simulation 2323
 
  • D. Wollmann, T. Baumbach, A. Bernhard, P. Peiffer
    University of Karlsruhe, Karlsruhe
  • R. Rossmanith
    FZK, Karlsruhe
  Undulators are the most advanced sources for the generation of synchrotron radiation. The photons generated by a single electron add up coherently along the electron trajectory. In order to do so the oscillatory motion of the electron has to be in phase with the emitted photons along the whole undulator. Small magnetic errors can cause unwanted destructive interferences. In standard permanent magnet undulators the magnetic errors are reduced by applying shimming techniques. Superconductive undulators have higher magnetic fields than permanent magnet undulators but shimming is more complex. In this paper it is shown that coupled superconductive loops installed along the surface of the superconductive undulator coil can significantly reduce the destructive effect of the field errors. This new idea might allow the building of undulators with a superior field quality.  
 
WEPC150 Fast Local Bump System for Helicity Switching at the Photon Factory undulator, vacuum, kicker, alignment 2356
 
  • K. Harada, Y. Kobayashi, T. Miyajima, S. Nagahashi, T. Obina
    KEK, Ibaraki
  • S. Matsuba
    Hiroshima University, Graduate School of Science, Higashi-Hiroshima
  Two APPLE-II type variably polarizing undulators will be installed at the south straight section of the PF (Photon Factory) ring. The 10Hz fast orbit switching in these undulators will be conducted for the helicity switching. The required angular difference of the orbits in two undulators is 0.3mrad. The five identical bump magnets and AC power supplies are manufactured to make 10Hz time varying local bumps. In order to achieve the local bump and prevent the fluctuation of the beam orbit with the effects of the insertion devices and magnetic errors, the feed forward correction with the bump magnets and the feedback correction with the fast steering magnets are required. In this presentation, the measurement results of the magnetic field and the frequency response, the configuration of the control system, and the simulation results to achieve the local bumps are shown.  
 
WEPP162 Beam Impact Studies on ILC Collimators simulation, electron, controls, target 2865
 
  • G. Ellwood
    STFC/RAL, Chilton, Didcot, Oxon
  • J.-L. Fernandez-Hernando, J. K. Jones
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • M. Slater, N. K. Watson
    Birmingham University, Birmingham
  Spoilers in the ILC Beam Delivery System are required to survive without failure a minimum of 1-2 direct impacts of 250 GeV-500 GeV bunch of electrons or positrons, in addition to maintaining low geometric and resistive wall wake fields. Simulations were completed to determine the energy deposition of an ILC bunch to a set of different spoiler designs. These shower simulations were used as inputs to thermal and mechanical studies using ANSYS. This paper presents the results of testing carried out at the Accelerator Test Facility at KEK used to validate the simulations. Results from the first phase of testing, in which electron bunches of varying charge were incident on TI-6Al-4V foils, are presented and compared with simulations.  
 
WEPP168 Mechanical Design of Collimators for the ILC radiation, vacuum, linear-collider, collider 2883
 
  • B. D. Fell, D. Angal-Kalinin, S. C. Appleton, J.-L. Fernandez-Hernando, F. Jackson, O. B. Malyshev
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • N. Bliss
    STFC/DL, Daresbury, Warrington, Cheshire
  • G. Ellwood, R. J.S. Greenhalgh
    STFC/RAL, Chilton, Didcot, Oxon
  • J. D.A. Smith
    Cockcroft Institute, Warrington, Cheshire
  • N. K. Watson
    Birmingham University, Birmingham
  Much attention has been paid to the optimisation of the geometry and material of collimators in the ILC to mitigate the effects of both short-range transverse wakefields and errant beam impacts. We discuss the competing demands imposed by realistic engineering constraints and present a preliminary engineering design for adjustable jaw spoilers for the ILC.  
 
THPC115 Commissioning of SOLEIL Fast Orbit Feedback system feedback, storage-ring, insertion, controls 3248
 
  • N. Hubert, L. Cassinari, J.-C. Denard, J.-M. Filhol, N. Leclercq, A. Nadji, L. S. Nadolski, D. Pedeau
    SOLEIL, Gif-sur-Yvette
  The Fast Orbit Feedback system at SOLEIL is fully integrated into the BPM system equipped with Libera modules. Indeed, the correction algorithm has been embedded into the Libera FPGA which directly drives the power supplies of dedicated air coil correctors. The beam position measurements of the 120 BPMs are distributed around the storage ring by a dedicated network. Then, the correction is computed and applied at a rate of 10 kHz to 48 correctors installed over stainless-steel bellows, on each side of every straight section. The BPM system has been operational for some time. The fast orbit feedback system is in its commissioning phase. The design and first results of the latter are reported.  
 
THPC139 Properties of X-ray Beam Position Monitors at the Swiss Light Source feedback, vacuum, electron, controls 3312
 
  • T. Wehrli, M. Böge, J. Krempasky, E. D. van Garderen
    PSI, Villigen
  Tungsten blade type X-ray beam position monitors (X-BPMs) are widely used at the SLS to stabilize the photon beam position at the the micron level. Various slow (~0.5 Hz) photon beam position feedbacks (SPBPFs) being an integral part of the global orbit feedback system have been in operation for several years. They are solely based on one X-BPM reading assuming that the photon beam movement is dominated by angle changes of the electron beam. This paper reports on the operation of the first SPBPF using two X-BPMs. This allows the separation of positional and angular variations of the electron beam, which is of special importance for the recently commissioned PolLux dipole beamline, as it is mostly sensitive to position changes. Correlations between the electron beam movement and the X-BPM readings are extensively analyzed in order to disentangle systematic errors of the position determination and real orbit motion. Methods are presented on how to recognize and correct or even avoid large systematic errors of the X-BPMs. With this knowledge, the demanding requirements on X-BPM accuracy in case of a SPBPF utilizing two X-BPMs could be fulfilled for the first time at the SLS.  
 
THPC143 A Wide Range Electrons, Photons, Neutrons Beam Facility electron, linac, positron, diagnostics 3321
 
  • B. Buonomo, G. Mazzitelli, F. Murtas, L. Quintieri
    INFN/LNF, Frascati (Roma)
  • P. Valente
    INFN-Roma, Roma
  The DAΦNE Beam Test Facility is in operation since the 2003 and has been continuously improved and upgraded in order to take into account the many different requests coming from the high energy and accelerator community. The facility was initially optimized to produce single electron and positron in the 25-750 MeV energy rage, manly for high energy detector calibration and testing; it can now provide beam in a wider range of intensity, up to 1010 electrons/pulse, typically needed for accelerator diagnostic tests. In the last two years the facility has also been modified in order to produce tagged photons, and the possibility to deliver tagged neutrons in the MeV energy range is under study. The main results obtained, the performance and the most significant characteristics of the facility diagnostics and operation are presented, as well as the users experience collected during these years of operation.  
 
THPC157 A Simple Method for Timing an XFEL Source to High-power Lasers undulator, electron, radiation, laser 3357
 
  • G. Geloni, E. Saldin, E. Schneidmiller, M. V. Yurkov
    DESY, Hamburg
  We propose a technique for timing an XFEL to a high-power laser with femtosecond accuracy. The same electron bunch is used to produce an XFEL pulse and an ultrashort optical pulse that are, thus, naturally synchronized. Cross-correlation techniques will yield the relative jitter between the optical pulse (and, thus, the XFEL pulse) and a pulse from an external pump-laser with femtosecond resolution. Technical realization will be based on an optical replica synthesizer (ORS) setup to be installed after the final bunch-compressor. The electron bunch is modulated in the ORS by an external optical laser. Travelling through the main undulator, it produces the XFEL pulse. Then, a powerful optical pulse of coherent edge radiation is generated as the bunch passes through a long straight section and a separation magnet downstream of the main undulator. Relative synchronization of these pulses is preserved using the same mechanical support for X-ray and optical elements transporting radiation to the experimental area, where single-shot cross-correlation between optical pulse and pump-laser pulse is performed. We illustrate our technique with numerical examples referring to the European XFEL.  
 
THPP141 Test of a NEG Coated Copper Dipole Vacuum Chamber vacuum, dipole, storage-ring, synchrotron 3693
 
  • E. J. Wallén, M. Berglund, A. Hansson
    MAX-lab, Lund
  • R. Kersevan
    ESRF, Grenoble
  The paper reports about a test carried out at the 1.5 GeV storage ring MAX II where a standard dipole chamber made of stainless steel was replaced by a NEG coated chamber made of copper. The standard MAX II stainless steel dipole vacuum chamber is connected to an ion pump and a sublimation pump while the NEG-coated copper dipole vacuum chamber has no additional pumps. The NEG-coated dipole chamber made of copper has been demonstrated to work well with a stable vacuum level in the region where it is installed. The coating procedure for the bent dipole chamber copper tube is slightly more complicated than the coating procedure for a straight chamber of similar size due to its curvature and lack of line-of-sight. The procedure is also described in some detail. The main motivation for the interest in NEG-coated vacuum tubes is the reduced cost of the vacuum system and also the possibility to build more slender vacuum systems, thus simplifying and optimizing the design of accelerator magnet systems.  
 
THPP142 Vacuum Conditioning of the SOLEIL Storage Ring with Extensive Use of NEG Coating vacuum, quadrupole, storage-ring, synchrotron 3696
 
  • C. Herbeaux, N. Béchu, J.-M. Filhol
    SOLEIL, Gif-sur-Yvette
  The vacuum system of the SOLEIL storage ring is designed using a combination of standard pumps like Sputter Ion Pumps and Titanium Sublimation Pumps (TSP) and Non Evaporable Getter (NEG) coating. Following the ESRF results on low gap insertion device (ID) chambers, it was decided to use, in addition to the traditional pumps, NEG coating deposited by magnetron sputtering on extruded aluminium vessels. This has been applied in an extensive way to all the straight vessels of the storage ring that means quadrupole vessels and ID vessels, which represent about 56% of the circumference. The starting configuration of the SOLEIL vacuum system included all the NEG coated low gap ID chambers among which a 10.5 m long chamber. Conditioning of the vacuum system over an integrated beam dose of 500 A.h will be presented. The periodical re-activations of the TSP performed early 2007 improved significantly the conditioning rate. A comparison of the vacuum behaviour of two similar cells one with NEG coating and traditional pumping versus one with only NEG coating demonstrates the ability of the NEG coating to keep alone the pressure at low level.  
 
THPP143 Vacuum Design of the TPS Relates to the Beam Effects vacuum, impedance, electron, ion 3699
 
  • G.-Y. Hsiung, C. K. Chan, C.-C. Chang, H. P. Hsueh, Z.-D. Tsai
    NSRRC, Hsinchu
  • J.-R. Chen
    NTHU, Hsinchu
  The concept of the vacuum design for the 3 GeV Taiwan Photon Source (TPS) considers several points of view which relates to the beam effects. The vacuum design of the low outgassing rate and the effective pumping configurations to obtain the lowest average pressure in the electron storage ring is to obtain the longer beam life time and the least of the ion trapping effect and the consequent problem of beam ion instability. The inner structure of the beam ducts provides the lower impedance which reduces the problems of the collective beam instability and the heating dissipation and damage to the vacuum components. The thin wall of the beam ducts and the bellows are designed for the sextupoles that offers the function of fast feedback orbit correction of the beam. The final performance of the third generation light source with low emittance will rely on the original design of vacuum systems for the electron beam. The design philosophy of the vacuum systems for the TPS will be described.  
 
THPP144 The Vacuum System for SSRF Storage Ring vacuum, synchrotron, power-supply, storage-ring 3702
 
  • D. K. Jiang, L. Chen, Y. L. Chen, W. Li, Y. Liu, Y. Lu, H. Zhang
    SINAP, Shanghai
  The vacuum system for SSRF was completed at the end of 2007 and has run for one month without any malfunction. The vacuum chamber for the storage ring made from stainless steel 316LN plate. About 180 absorbers and 80 RF bellows with a single finger structure are used for the storage ring. About 292 compound pumps (SIP+NEG) and 188 TSP are used. After the vacuum system in the straight section of a cell and all pumps in the bending section were baked, the ultimate pressure reached 2×10-8 Pa. Normally, the temperature raise on the chambers any where is less than 4℃ with current 100mA. The temperature raise of the cooling water for all absorbers is less than 3℃. The vacuum control and interlock system are on working order.  
 
THPP151 Feasibility Study for High Performance Vacuum Chamber vacuum, electron, storage-ring, positron 3720
 
  • Y. Tanimoto
    KEK, Ibaraki
  For longer beam lifetime, many synchrotron light sources employ ante-chamber type of beam ducts to reduce photon- and electron-stimulated desorption gases around stored beams. Still more reduction, however, can be expected if an X-ray transparent membrane, such as Beryllium thin film, is installed between the beam chamber and the ante-chamber because X-rays from stored beams pass through the membrane while gas molecules desorbed in the ante-chamber are shut out by the membrane. Similarly, photoelectrons and secondary electrons traveling from the ante-chamber to the beam chamber are also shut out by the membrane; this function is expected to mitigate beam-photoelectron instability in positron storage rings. Feasibility study for this type of vacuum chamber has been started at PF, and the result of the first-stage experiment will be presented.