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diagnostics

     
Paper Title Other Keywords Page
MOPCH011 Jitter Measurement by Spatial Electro-optical Sampling at the Flash Free Electron Laser laser, electron, FEL, polarization 71
 
  • A. Azima, S. Düsterer, J. Feldhaus, H. Schlarb
    DESY, Hamburg
  • A.L. Cavalieri
    MPQ, Garching, Munich
  • D. Fritz
    Michigan University, Ann Arbor, Michigan
  • K. Sengstock
    Uni HH, Hamburg
  For pump-probe experiments carried out at the VUV-FEL at DESY, FEL laser pulses with 32 nm wavelength have to be synchronized with high precision to optical laser pulses generated by a TiSa oscillator. To measure the relative timing variations between the FEL and the optical laser, an electro-optical experiment to determine the electron beam arrival time at the undulator has been installed. Here, the electron beam profile is encoded spatially into the laser pulse and readout by an intensified camera. A similar experimental setup has been successfully used at the sub-picosecond pulsed source (SPPS) at higher charge and shorter rms bunch length. In this paper, we report about the achievements and difficulties of the Timing Electro-Optical (TEO) setup, that allows to post-order experimental user data with a precision of 100 fs rms and better.  
 
MOPCH070 The Status of the Daresbury Energy Recovery Prototype Project gun, ERLP, linac, electron 187
 
  • D.J. Holder, J.A. Clarke, P.A. McIntosh, M.W. Poole, S.L. Smith
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • N. Bliss
    CCLRC/DL, Daresbury, Warrington, Cheshire
  • E.A. Seddon
    CCLRC/DL/SRD, Daresbury, Warrington, Cheshire
  The major component of the UK's R&D programme towards an advanced energy recovery linac-based light source facility is a 35 MeV technology demonstrator called the energy recovery linac prototype (ERLP). This is based on a combination of a DC photocathode electron gun, a superconducting linac operated in energy recovery mode and an IR FEL. The current status of the of this project is presented, including the construction and commissioning progress and plans for the future exploitation of this scientific and technical R&D facility.  
 
MOPLS081 A Study of Laser System Requirements for Application in Beam Diagnostics and Polarimetry at the ILC laser, controls, luminosity, optics 741
 
  • S. Dixit, N. Delerue, K.J. Peach
    JAI, Oxford
  • G.A. Blair, S.T. Boogert, G.E. Boorman, A. Bosco, C. Driouichi
    Royal Holloway, University of London, Surrey
  • A. Brachmann, J.C. Frisch, M.C. Ross
    SLAC, Menlo Park, California
  • F.B. Foster, D.F. Howell, Q.G. Quelch, Q.M. Qureshi, A. Reichold
    OXFORDphysics, Oxford, Oxon
  • G.J. Hirst, I. N. Ross
    CCLRC/RAL, Chilton, Didcot, Oxon
  • V. Soskov, V. Variola, Z.F. Zomer
    LAL, Orsay
  • J. Urakawa
    KEK, Ibaraki
  Advanced laser systems will be essential for a range of diagnostics devices at the ILC. High average power, excellent stability and reliability will be crucial in order to deliver the information required to attain the necessary ILC luminosity. The key parameters are listed together with the R&D required to achieve the necessary laser system performance.  
 
MOPLS103 A High-gradient Test of a 30 GHz Molybdenum-iris Structure CLIC, CTF3, electron, vacuum 801
 
  • W. Wuensch, C. Achard, H.-H. Braun, G. Carron, R. Corsini, S. Doebert, R. Fandos, A. Grudiev, E. Jensen, T. Ramsvik, J.A. Rodriguez, J.P.H. Sladen, I. Syratchev, M. Taborelli, F. Tecker, P. Urschütz, I. Wilson
    CERN, Geneva
  • H. Aksakal
    Ankara University, Faculty of Sciences, Tandogan/Ankara
  • Ö.M. Mete
    Ankara University, Faculty of Engineering, Tandogan, Ankara
  The CLIC study is investigating a number of different materials as part of an effort to find ways to increase achievable accelerating gradient. So far, a series of rf tests have been made with a set of identical-geometry structures: a tungsten-iris 30 GHz structure, a molybdenum-iris 30 GHz structure and a scaled molybdenum-iris X-band structure. A second molybdenum-iris 30 GHz structure of the same geometry has now been tested in CTF3 with pulse lengths up to 350 ns. The new results are presented and compared to those of the previous structures to determine dependencies of quantities such as accelerating gradient, material, frequency, pulse length, power flow, conditioning rate and breakdown rate.  
 
TUYPA01 Femtosecond Bunch Length Measurements radiation, laser, electron, CDR 915
 
  • S.P. Jamison
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • G. Berden
    FOM Rijnhuizen, Nieuwegein
  • W.A. Gillespie, P.J. Phillips
    University of Dundee, Nethergate, Dundee, Scotland
  • A. MacLeod
    UAD, Dundee
  • B. Steffen
    DESY, Hamburg
  The measurement of ultrashort longitudinal bunch profiles is of growing importance to accelerator development and operation. With requirements of ~10fs time resolution, and a desire for non-destructive and real time diagnostics, the challenges for diagnostic development are significant. Alongside more established transverse deflecting cavity and CTR measurement techniques, new approaches arriving from the field of ultrafast lasers offer significant potential; Ultrafast electro-optic detection has now been demonstrated on several accelerators, and in many distinct forms, although challenges remain in getting to the desired time resolution. Proposed schemes combining ultrafast laser diagnostics with FEL interactions, such as the "optical replica" scheme also have considerable potential. Here, an overview of the current status of femtosecond scale longitudinal profile diagnostics will be given, together with an outlook to the future expectations.  
slides icon Transparencies
 
TUYPA02 High Precision SC Cavity Alignment Diagnostics with HOM Measurements dipole, alignment, linac, feedback 920
 
  • J.C. Frisch, L. Hendrickson, J. May, D.J. McCormick, S. Molloy, M.C. Ross, T.J. Smith
    SLAC, Menlo Park, California
  • N. Baboi, O. Hensler, L.M. Petrosyan
    DESY, Hamburg
  • N.E. Eddy, S. Nagaitsev
    Fermilab, Batavia, Illinois
  • O. Napoly, R. Paparella, C. Simon
    CEA, Gif-sur-Yvette
  Experiments at the TTF at DESY have demonstrated that the Higher Order Modes induced in Superconducting Cavities can be used to provide a variety of beam and cavity diagnostics. The centers of the cavities can be determined from the beam orbit which produces minimum power in the dipole HOM modes. The phase and amplitude of the dipole modes can be used as a high resolution beam position monitor, and the phase of the monopole modes to measure the beam phase relative to the accelerator RF. Beam orbit feedback which minimizes the dipole HOM power in a set of structures has been demonstrated. For most SC accelerators, the existing HOM couplers provide the necessary signals, and the downmix and digitizing electronics are straightforward, similar to those for a conventional BPM.  
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TUOBFI01 A Diagnostic Kicker System as a Versatile Tool for Storage Ring Characterisations kicker, storage-ring, controls, synchrotron 974
 
  • O. Dressler, J. Feikes, J. Kolbe
    BESSY GmbH, Berlin
  For the BESSY II Synchrotron Light Source two diagnostic kicker systems including current pulsers were developed, allowing vertical and horizontal deflection of the stored beam. Synchronised with the revolution trigger, simultaneous pulsing of the systems kicks the stored beam in any transverse direction with a repetition rate of up to 10 Hz allowing a wide range of storage ring investigations. Examples are dynamic aperture measurements and frequency map measurements. Special efforts were made to assure the demands of high amplitude and time stability for this kind of experiments. The technical concept of the systems and the controlling of the measurements are described.  
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TUPCH003 Diagnostics and Timing at the Australian Synchrotron storage-ring, injection, synchrotron, kicker 995
 
  • M.J. Spencer, S. Banks, M.J. Boland, M. Clift, R.T. Dowd, R. Farnsworth, S. Hunt, G. LeBlanc, M. Mallis, B. Mountford, Y.E. Tan, A. Walsh, K. Zingre
    ASP, Clayton, Victoria
  The 3GeV Australian Synchrotron will begin operation in March 2007. This paper outlines the storage ring diagnostics systems and the injection timing system. The diagnostics system includes an optical beamline with streak camera, an x-ray beamline with pinhole array, a diagnostic straight with fast feedback kicker, stripline, direct current current transformer, and a four-fingered scraper. Over the 14 sectors there are 98 beam position monitors and 14 movable beam loss monitors. The timing system is based on a static injection system with the storage ring bucket to be filled targeted by delaying the firing of the electron gun.  
 
TUPCH004 Commissioning of the LNLS X-ray BPMs electron, dipole, feedback, synchrotron 998
 
  • S.R. Marques, P.F. Tavares
    LNLS, Campinas
  We present experimental results of the commissioning of staggered-pair blade X-Ray beam position monitor (XBPM) recently developed and installed at the diagnostic beamline of the UVX electron storage ring at the Brazilian Synchrotron Light Laboratory (LNLS). The results obtained with a prototype XBPM indicate that the short-term and long-term data are both in agreement with the data from a commercially acquired XBPM installed at the same beamline, as well as with the data of the electron storage ring RF BPMs. In this paper we present the commissioning results of the LNLS XBPM.  
 
TUPCH011 Innovative Beam Diagnostics for the Challenging FAIR Project synchrotron, ion, feedback, cryogenics 1016
 
  • P. Forck, A. Peters
    GSI, Darmstadt
  The planned FAIR facility consists of two heavy ion synchrotrons and four large storage rings. The super-conducting synchrotrons are build for high current operation and secondary ion production. A large variety of low current secondary beams is stored and cooled in the four storage rings. A complex operation scheme with multiple use of transport lines is foreseen. This demands an exceptional high dynamic range for the beam instrumentation. Due to the enormous beam power, non-destructive methods are mandatory for high currents. For the low current secondary beams, non-destructive diagnostics are also preferred due to the low repetition rate. Precise measurements of all beam parameters and automatic steering or feedback capabilities are required due to the necessary exploitation of the full ring acceptances. Moreover, online beam-corrections with short response times are mandatory for the fast ramping super-conducting magnets. Due to the ultra-high vacuum condition and the demanding measurement accuracy, novel technical solution are foreseen. An overview of the challenges and projected innovative solutions for various diagnostic installations will be given.  
 
TUPCH015 Integrated Beam Diagnostics Systems for HICAT and CNAO controls, linac, GSI, ion 1028
 
  • A. Reiter, A. Peters, M. Schwickert
    GSI, Darmstadt
  An integrated system for beam diagnostics was produced at GSI for the heavy-ion cancer treatment facility HICAT of the Heidelberg university clinics. A set of 92 manifold beam diagnostic devices allows automated measurements of the main beam parameters such as beam current, profile or energy. The beam diagnostic subsystem is completely integrated in the overall accelerator control system and its timing scheme. This paper reports on the underlying design patterns for the abstraction of the beam diagnostic devices towards the control system. Event-counting devices, i.e. scintillating counters and ionization chambers, are presented as examples of the diagnostic devices in the synchrotron and high-energy beam transport section of HICAT. Additionally, it is shown that the well-defined building blocks of the beam instrumentation made it possible to prepare almost identical devices including the manual control software, to be used in the CNAO facility (Centro Nazionale di Adroterapia Oncologica) presently under construction in Pavia, Italy.  
 
TUPCH018 Fast Beam Dynamics Investigation Based on an ADC Filling Pattern Measurement CBM, synchrotron, controls, storage-ring 1034
 
  • J. Kettler, P. Hartmann, R.G. Heine, T. Weis
    DELTA, Dortmund
  A diagnostic tool to determine the longitudinal particle filling pattern has been installed at the 1.5 GeV electron storage ring DELTA. The instrument is PC-based using an ADC-conversion at a sampling rate of 2 GS/s and a nominal bandwidth of 1 GHz which is applied to the sumsignal of a single storage ring beam position monitor. By sampling over successive turns the resolution is enhanced by one order of magnitude allowing an easy access to the longitudinal particle distribution inside the ring. The data obtained turn-by-turn over hundreds of revolutions can be further analysed by FFT-techniques allowing a very fast detection (~ 1 s) of longitudinal coupled bunch mode (CBM) instabilities from the phase modulated spectrum. The application of the FFT to the amplitude modulated particle distribution moreover allows a "post mortem"-investigation of CBM induced beam loss. The paper will present the layout of the diagnostic system and will report on filling pattern measurements as well as on investigations of longitudinal CBM-instabilities.  
 
TUPCH021 Principles of longitudinal beam diagnostics with coherent radiation electron, radiation, DESY, laser 1040
 
  • O. Grimm
    DESY, Hamburg
  The Kramers-Kronig dispersion relation connects the real and imaginary part of a response function under very general assumptions. It is used in the context of accelerator physics for longitudinal bunch diagnostics as a phase retrieval technique: the modulus of the complex form factor (the Fourier transform of the charge distribution) is accessible experimentally, and the missing phase then (partially) reconstructed to allow an inversion of the Fourier transform. Contrary to real and imaginary part, the connection between modulus and phase is not unique anymore due to the possibility of zeros of the form factor in the complex frequency plane that cannot be measured. This paper gives a mathematically explicit, step-by-step derivation of the phase reconstruction technique for bunch diagnostics, and it explains the problem of zeros and their practical effect with some examples. The intention is not utmost mathematical rigour, but a clear, accessible explanation of all steps involved.  
 
TUPCH028 Layout of the Optical Synchronization System for FLASH laser, electron, feedback, DESY 1061
 
  • A. Winter, P. Schmüser, A. Winter
    Uni HH, Hamburg
  • F. Loehl, F. Ludwig, H. Schlarb, B. Schmidt
    DESY, Hamburg
  The present RF synchronization system of the VUV-FEL can typically stabilize the arrival time of the electron bunches at the undulator to about 200 fs on a timescale of minutes and to several picoseconds on a timescale of hours. To improve the machine stability and to ensure optimal performance for the VUV-FEL user facility, a new ultra-precise timing system is mandatory. The optical synchronization system under construction will satisfy three goals: Firstly, it provides a local oscillator frequency with the same stability as the existing low-level RF regulation, secondly, it can synchronize the experimental lasers of the FEL users with a precision in the order of 30 fs, thirdly, it provides an ultra-stable reference for beam arrival time measurements and enables a feedback on the electron beam to compensate residual drifts and timing jitter. The optical synchronization system is based on an optical pulse train from a mode-locked laser with a highly stabilized repetition rate. This paper describes the proposed layout of the optical synchronization system, the integration into the machine layout and the diagnostic experiments to monitor the performance of the system.  
 
TUPCH030 A Beam Diagnostics System for the Heidelberg Cryogenic Storage Ring CSR CSR, ion, electron, pick-up 1067
 
  • T. Sieber, H. Fadil, M. Grieser, A. Wolf, R. von Hahn
    MPI-K, Heidelberg
  The storage of rotationally non-excited molecules and highly charged ions requires lowest temperatures and vacuum pressures. At the MPI-K Heidelberg a cryogenic storage ring (CSR) for atomic and molecular physics experiments is under development. The CSR shall allow operation at temperatures of 2 K and pressures down to 1·10-15 mbar. The ring consists of electrostatic elements and has a circumference of ~35 m. It is housed inside a large cryostat, cooled by a (20W @ 2K) Helium refrigerator. To reach low UHV pressures already at room temperature the whole machine has to be bakeable up to 300°C. These boundary conditions, together with the low charge states, low velocities and low intensities (1nA-1muA) of the ions, put strong demands on the beam diagnostics system. Some beam parameters like profile, position and intensity cannot be measured with “standard” beam diagnostics technology. Here new or further developments are required. The paper gives a general view of the beam diagnostics concept for the CSR and shows in more detail possible solutions for measurement of beam position and beam profile.  
 
TUPCH033 Automated Beam Optimisation and Diagnostics at MAMI microtron, linac, synchrotron, synchrotron-radiation 1076
 
  • M. Dehn, H. Euteneuer, F.F. Fichtner, A. Jankowiak, K.-H. Kaiser, W.K. Klag, H.J. Kreidel, S.S. Schumann, G.S. Stephan
    IKP, Mainz
  At the Institut fur Kernphysik (IKPH) of Mainz University the fourth stage of the Mainz Microtron (MAMI), a 855MeV to 1500MeV Harmonic Double Sided Microtron (HDSM), is now on the verge of first operation*. To provide an automated beam optimisation, low-Q-TM010 and TM110 resonators at each linac of the three cascaded RTMs and the two linacs of the new HDSM are used. These monitors deliver position, phase and intensity signals of each recirculation turn when modulating the beam intensity with 12ns-pulses (diagnostic pulses, max. rep. rate 10kHz). For operating the HDSM an extended system for displaying and digitising these signals was developed. High-bandwidth ADCs allow very comfortable to analyse, calibrate and automatically optimise the beam positions and phases during operation. The system is also used to adjust the transversal and longitudinal focussing according to the design parameters. Synchrotron radiation monitors, providing beam sizes and positions out of the bending magnets for each turn and on the entrance and exit of the linac axis, were a very helpful tool for beam-matching between the RTMs. Therefore a similar system was planned and constructed for the HDSM.

*A. Jankowiak et al. “Status Report on the Harmonics Double Sided Microtron of MAMI C”, this conference.

 
 
TUPCH039 A Phase Space Tomography Diagnostic for Pitz space-charge, quadrupole, PITZ, gun 1091
 
  • D.J. Holder, B.D. Muratori
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • F.E. Hannon
    Jefferson Lab, Newport News, Virginia
  • S. Khodyachykh, A. Oppelt
    DESY Zeuthen, Zeuthen
  The Photo Injector Test Facility at DESY in Zeuthen (PITZ) is a European collaboration developing RF photocathode electron guns for light source and linear collider projects. As part of the collaborative work being partially funded by the EU's FP6 programme, CCLRC Daresbury Laboratory and DESY are designing and building a phase space tomography diagnostic based on a set of multiple quadrupoles and view screens. In order to measure the beam emittance, four screens with intermediate quadrupole doublets will be used. The equipment will be installed and tested at PITZ as part of the facility upgrade presently ongoing. Following simulations of the gun using the ASTRA code at a range of energies, simulations of the electron beam parameters through the matching and tomography sections must be undertaken in order to specify the optimum arrangement of magnets and screens.  
 
TUPCH041 Electro-optic Diagnostics on the Daresbury Energy Recovery Linac electron, laser, CSR, free-electron-laser 1094
 
  • P.J. Phillips, W.A. Gillespie
    University of Dundee, Nethergate, Dundee, Scotland
  • S.P. Jamison
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • A. MacLeod
    UAD, Dundee
  An electro-optic longitudinal bunch profile monitor is being implemented on the 4GLS prototype energy recovery linac (ERL/p) at Daresbury Laboratories and will be used both to characterise the electron bunch and to provide a testbed for electro-optic techniques. The electro-optic station is located immediately after the bunch compressor, and within the FEL cavity; its location allows it to draw on nearby beam profile monitors and CTR and CSR diagnostics for calibration and benchmarking. We discuss the implementation and planned studies on electro-optic diagnostics with this diagnostic station.  
 
TUPCH062 Synchrotron Radiation Diagnostics for the NSLS Booster booster, synchrotron, synchrotron-radiation, radiation 1154
 
  • T.V. Shaftan, I. Pinayev
    BNL, Upton, Long Island, New York
  We developed an optical diagnostics system for the NSLS booster-synchrotron utilizing the synchrotron radiation from the dipole magnet. MATLAB based software allows to study the electron beam properties along the energy ramp. The trajectory, beam sizes and coupling at the different instants of time are retrieved from the analysis of the electron beam image. In the paper we present the system layout, as well as experimental results and upgrade plans.  
 
TUPCH073 Study of Beam Energy Spread at the VEPP-4M betatron, synchrotron, collider, scattering 1178
 
  • O.I. Meshkov, V. F. Gurko, A.D. Khilchenko, V. Kiselev, N.Yu. Muchnoi, A.N. Selivanov, V.V. Smaluk, A. N. Zhuravlev
    BINP SB RAS, Novosibirsk
  The knowledge of beam energy spread is necessary for the experimental program of the VEPP-4M collider. In this report we discuss the application of optical diagnostics for measurement of this value. The diagnostics is based on multi-anode photomultiplier and provides information about betatron and betetron frequencies of electron beam*. The beam energy spread is derived from the spectra of synchrotron oscillation. The results, obtained with this method, are compared with data, provided by Compton backscattering technique.

*O. I. Meshkov et al. Application of the beam profile monitor for VEPP-4M tuning. Proc. of DIPAC '05, June 6 - 8, 2005, Lyon, France, POM008.

 
 
TUPCH087 Beam Diagnostics with Schottky Noise in LEIR ion, pick-up, CERN, injection 1214
 
  • J. Tan, G. Tranquille
    CERN, Geneva
  The high density Lead ion beams, needed for LHC, are obtained in the Low Energy Ion Ring (LEIR) at CERN by multi-turn injection followed by electron cooling and stacking. During this injection and stacking phases where the circulating beam is unbunched, diagnostics with Schottky noise are used for probing essential beam parameters, such as tune, momentum spread, emittance and their evolution with time… The hardware facility and first results obtained during the recent commissioning of LEIR are described.  
 
TUPCH089 Investigations of OTR Screen Surfaces and Shapes CTF3, radiation, focusing, electron 1220
 
  • C.P. Welsch, E. Bravin, T. Lefevre
    CERN, Geneva
  Optical transition radiation (OTR) has proven to be a flexible and effective tool for measuring a wide range of beam parameters, in particular the beam divergence and the transverse beam profile. It is today an established and widely used diagnostic method providing linear real-time measurements. Measurements in the CLIC Test Facility (CTF3) showed that the performance of the present profile monitors is limited by the optical acceptance of the imaging system. In this paper, two methods to improve the systems' performance are presented and results from measurements are shown. First, the influence of the surface quality of the OTR screen itself is addressed. Several possible screen materials have been tested to which different surface treatment techniques were applied. Results from the measured optical characteristics are given. Second, a parabolic-shaped screen support was investigated with the aim of providing an initial focusing of the emitted radiation and thus to reduce the problem of aperture limitation. Measured and calculated emission distributions are presented.  
 
TUPCH100 Fiberoptics-based Instrumentation for Storage Ring Longitudinal Diagnostics synchrotron, radiation, coupling, synchrotron-radiation 1247
 
  • S. De Santis, J.M. Byrd, A. Ratti, M.S. Zolotorev
    LBNL, Berkeley, California
  • Y. Yin
    Y.Y. Labs, Inc., Fremont, California
  Many beam diagnostic devices in today's synchrotron rings make use of the radiation emitted by the circulating particles. Such instruments are placed in close proximity of the accelerator, where in many instances they cannot be easily accessed for safety consideration, or at the end of a beamline, which because of its cost, can only move the light port a few meters away from the ring. We present a study on the coupling of synchrotron light into an optical fiber for all those application where the longitudinal properties of the beam are measured (i.e., bunch length, phase, intensity, etc.). By choosing an appropriate fiber it is possible to keep attenuation and dispersion at negligible values over a large bandwidth, so that this method would allow to have the diagnostic instruments directly in the control room, or wherever convenient, up to several hundred of meters away from the tunnel. This would make maintaining and replacing instruments, or switching between them, possible without any access to restricted areas. Additionally, the few components required to be near the ring (lenses and couplers) in order to couple the light into the fiber are intrinsically radiation-hard.  
 
TUPCH106 Commissioning the SPEAR3 Diagnostic Beamlines single-bunch, optics, coupling, photon 1259
 
  • W.J. Corbett, C. Limborg-Deprey, W.Y. Mok, A. Ringwall
    SLAC, Menlo Park, California
  SPEAR 3 has two diagnostic beam lines: an x-ray pinhole camera and a visible/UV laboratory. The pinhole camera images ~8 keV dipole radiation on a phosphor screen with a remote computer to capture digital profile images. The visible/UV beam line features an 8 mm high GlidCop 'cold finger' to remove the x-ray core of the beam. The remaining light is deflected horizontally onto an optical bench where it is focused via reflective (Cassegrain) or refractive optics. The visible beam is then split into branch lines for a variety of experimental applications. This paper describes the experimental arrangement, data processing algorithms and measurements obtained with both systems.  
 
TUPCH196 Digital Design of the LHC Low Level RF: the Tuning System for the Superconducting Cavities controls, LHC, CERN, feedback 1474
 
  • J.C. Molendijk, P. Baudrenghien, A. Butterworth, E. Ciapala, R. Olsen, F. Weierud
    CERN, Geneva
  • R. Sorokoletov
    JINR, Dubna, Moscow Region
  The low level RF systems for the LHC are based extensively on digital technology, not only to achieve the required performance and stability but also to provide full remote control and diagnostics facilities needed in a machine where most of the RF system is inaccessible during operation. The hardware is based on modular VME but with additional low noise linear power supplies and a specially designed P2 backplane for timing distribution and fast data interchange. Extensive design re-use and the use of graphic FPGA design tools have streamlined the design process. A milestone was the test of the tuning system for the superconducting cavities. The tuning control module is based on a 2M gate FPGA with on-board DSP. Its design and functionality are described, including features such as automatic measurements of cavity characteristics and transient response of the tuning system. The tuner control is used as a test bed for LHC standard software components. A full 'vertical slice' from remote application down to the hardware has been tested. Work is ongoing on the completion of other modules and building up the software and diagnostics facilities needed for RF system commissioning.  
 
TUPLS096 Strongly Focused He+ Beam Source for Alpha Particle Measurement at ITER plasma, ion, extraction, ion-source 1726
 
  • K. Shinto, S. Kitajima, A. O. Okamoto, M. Sasao
    Tohoku University, Sendai
  • Y. H. Hirano, S. Kiyama, H. S. Sakakita
    AIST, Tsukuba, Ibaraki
  • O. Kaneko, M. Nishiura
    NIFS, Gifu
  • M. Wada
    Doshisha University, Graduate School of Engineering, Kyoto
  A He+ beam source for He0 beam probe for measurement of fusion produced alphas due to D-T nuclear reaction in a thermonuclear fusion plasma has been designed and constructed. The ion source consists of a 300 mm diameter and 280 mm length plasma chamber and a beam extraction system which has three concaved electrodes. Helium plasma is confined by line cusp magnetic fields produced by Sm-Co permanent magnets. The magnetic field strength near the extraction region is designed to be less than 20 gauss. Through the 100 mm diameter extraction area of the concaved electrodes 300 beamlets are formed with apertures of 4 mm. The focal length of the concaved electrodes is designed to be 750 mm. The beam quality of the extracted He+ beam will be measured by several beam diagnostic apparatuses. The total beam current, the beam profile and the beam emittance will be measured to design a proper alkali metal vapor cell for a He- beam production by a double charge exchange process and a beam transport line to the post accelerator up to MeV region. In the article, the details of the ion source and the beam diagnostic system will be described.  
 
WEPLS023 The Two-beam Test-stand in CTF3 CLIC, CTF3, linac, dipole 2445
 
  • V.G. Ziemann, T. J. C. Ekelof, M. A. Johnson
    UU/ISV, Uppsala
  • H.-H. Braun, S. Doebert, G. Geschonke, J.P.H. Sladen, W. Wuensch
    CERN, Geneva
  The acceleration concept for CLIC, based on the two-beam acceleration scheme, where the 30 GHz RF power needed to accelerate the high energy beam is generated by a high-intensity but rather low energy drive beam, will be tested in the two-beam test-stand in CTF3. There RF-structures will be tested at full pulse length. The extreme power levels of up to 640 MW warrant a careful diagnostic system to analyze RF breakdown by observing the effect on both probe- and drive-beam but also the RF signals and secondary effects such as emitted light, vibrations, vacuum, temperatures. We describe the experimental setup and the diagnostic system planned to be installed in CTF3 for 2007.  
 
WEPLS099 Fault Detection and Identification Methods Used for the LHC Cryomagnets and Related Cabling impedance, LHC, cryogenics, superconducting-magnet 2607
 
  • D. Bozzini, F. Caspers, V. Chareyre, Y. Duse, T. Kroyer, R. Lopez, A. Poncet, S. Russenschuck
    CERN, Geneva
  Several non-standard methods for electrical fault location have been successfully developed and tested. As part of the electrical quality assurance program, certain wires have to be subjected to a (high) DC voltage for the testing of the insulation. With the time difference of spark-induced electromagnetic signals measured with an oscilloscope, fault localization within a ± 10 cm range has been achieved. Another method used and adapted for the particular needs, was the synthetic pulse time-domain reflectometry (TDR) by means of a vector network analyzer. This instrument has also been applied as a low frequency sweep impedance analyzer in order to measure fractional capacities of cable assemblies where TDR was not applicable.  
 
WEPLS143 SLS Operation Management: Methods and Tools controls, SLS, feedback, power-supply 2715
 
  • A. Lüdeke
    PSI, Villigen
  Users of 3rd generation synchrotron light sources desire not only a high flux on their samples and sub-micron beam stability, they expect at the same time a beam availability close to 100 percent. To reach and maintain a very high availability put special demands on the operation management of a light source. We will illustrate the procedures used at the Swiss Light Source (SLS) to deal with beam interruptions and explain the tools used for operation management.  
 
THPPA01 High-precision Laser Master Oscillators for Optical Timing Distribution Systems in Future Light Sources laser, feedback, electron, FEL 2747
 
  • A. Winter, P. Schmüser, A. Winter
    Uni HH, Hamburg
  • J. Chen, F.X. Kaertner
    MIT, Cambridge, Massachusetts
  • F.O. Ilday
    Bilkent University, Bilkent, Ankara
  • F. Ludwig, H. Schlarb
    DESY, Hamburg
  Abstract to be supplied  
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THPCH085 The Longitudinal Coupled Bunch Feedback for HERA-p feedback, kicker, luminosity, controls 2985
 
  • M.G. Hoffmann, S. Choroba, F.E. Eints, U. Hurdelbrink, P.M. Morozov, J. Randhahn, S. Ruzin, S. Simrock, E. Vogel, R. Wagner
    DESY, Hamburg
  A longitudinal broadband damper system to control coupled bunch instabilities has recently been constructed and installed in the 920~GeV proton accelereator HERA-p at the Deutsches Elektronen-Synchrotron DESY. This represents one of the attempts to increase the specific luminosity at HERA by reducing the bunch length. The final bunch length is defined by the initial emittance after injection and by the acceleration process where multiply occuring coupled bunch instabilities provoke bunch length blow up at discrete energies during the ramp. The actual feedback design consists of a fast, high precision bunch centroid phase detector, a 1~kW feedback cavity with 104~MHz centre frequency and 8~MHz bandwidth (FWHM), a I/Q-vector modulator, the low level digital FPGA-board with 14 Bit ADCs and DACs and a cavity transient diagnostics. The system measures the phases of all bunches and calculates corrections in real time (bunch spacing: 96~ns) which are then applied to the beam via a longitudinal kicker. The filter deals with a slowly changing synchrotron frequency (20-80 Hz).  
 
THPCH102 Fast Global Orbit Feedback System in SPEAR3 feedback, controls, power-supply, undulator 3035
 
  • A. Terebilo, T. Straumann
    SLAC, Menlo Park, California
  New digital global orbit feedback system is under commissioning in SPEAR3 light source. The system has 4kHz sampling rate and 200Hz bandwidth. Correction algorithm is based on Singular Value Decomposition (SVD) of the orbit response matrix. For performance tuning and additional flexibility when adding or removing correctors and BPMs, we implemented an independent PID control loop for every orbit eigenvector used. This paper discusses performance of the new system and some advantages of multiple PID loops in the eigenvector space versus a single PID loop working on the raw orbit error.  
 
THPCH103 Design and Testing of Gproto Bunch-by-bunch Signal Processor feedback, luminosity, damping, injection 3038
 
  • D. Teytelman, R. Akre, J.D. Fox, A. Krasnykh, C.H. Rivetta, D. Van Winkle
    SLAC, Menlo Park, California
  • A. Drago
    INFN/LNF, Frascati (Roma)
  • J.W. Flanagan, T. Naito, M. Tobiyama
    KEK, Ibaraki
  A prototype programmable bunch-by-bunch signal acquisition and processing channel with multiple applications in storage rings has been developed at SLAC. The processing channel supports up to 5120 bunches with bunch spacings as close as 1.9 ns. The prototype has been tested and operated in five storage rings: SPEAR-3, DAFNE, PEP-II, KEKB, and ATF damping ring. The testing included such applications as transverse and longitudinal coupled-bunch instability control, bunch-by-bunch luminosity monitoring, and injection diagnostic. In this contribution the prototype design will be described and its operation will be illustrated with the data measured at the abovementioned accelerators.  
 
THPCH120 Development of a General Purpose Power System Control Board controls, SLAC, induction, impedance 3083
 
  • S.H. Nam, S.-H. Jeong, S.H. Kim, S.-C. Kim, S.S. Park, J.-H. Suh
    PAL, Pohang, Kyungbuk
  • P. Bellomo, R. Cassel, R. Larsen, M.N. Nguyen
    SLAC, Menlo Park, California
  As high frequency switching solid state devices are replacing tube devices and linear devices, power systems become more compact and modular. In those systems, it is desirable to have a high quality and multi-function control board per each power system module. In order to maintain reliable operation of the power system module, the control board requires having multiple and complex functions. Moreover, the control board needs to be compact and low power consuming. It also needs to have a fast communication with the main control station. However, there is no such control board available commercially. Therefore, a general purpose power system control board (PSCB) has been under development since 2005 as a collaboration effort between PAL and SLAC. The PSCB is an embedded, interlock supervisory, diagnostic, timing, and set-point control board. It is designed to use in various power systems such as sequenced kicker pulsers, solid state RF modulators, simple DC magnet power supplies, etc. The PSCB has the Ethernet communication with the TCP/IP Modbus protocol. This paper will describe detail functions and preliminary test results of the PSCB.  
 
THPCH153 Production of Temporally Flat Top UV Laser Pulses for SPARC Photoinjector laser, target, emittance, electron 3152
 
  • M. Petrarca, P. Musumeci
    INFN-Roma, Roma
  • I. Boscolo, S. Cialdi
    INFN-Milano, Milano
  • G. Gatti, A. Ghigo, C. Vicario
    INFN/LNF, Frascati (Roma)
  • M. Mattioli
    Università di Roma I La Sapienza, Roma
  In the SPARC photoinjector, the amplified Ti:Sa laser system is conceived to produce an UV flat top pulse profile required to reduce the beam emittance by minimizing the non-linear space charge effects in the photoelectrons pulse. Beam dynamic simulations indicate that the optimal pulse distribution must be flat top in space and time with 10 ps FWHM duration, 1 ps of rise and fall time and a limited ripple on the plateau. In a previous work~\cite{loose} it was demonstrated the possibility to use a programmable dispersive acousto-optics (AO) filter to achieve pulse profile close to the optimal one. In this paper we report the characterization of the effects of harmonics conversion on the pulse temporal profile. A technique to overcome the harmonics conversion distortions on the laser pulses at the fundamental wavelength in order to obtain the target pulse profile is explained too. Measurements and simulations in the temporal and spectral domain at the fundamental laser wavelength and at the second and third harmonics are presented in order to validate our work. It is also described a time diagnostic device for the UV pulses.

*H. Loos et al. "Temporal E-Beam Shaping in an S-Band Accelerator", Proc. Particle Accelerator Conference, p.642, 2005, Knoxville, TN, USA.

 
 
THPLS002 X-ray and Optical Diagnostic Beamlines at the Australian Synchrotron Storage Ring storage-ring, synchrotron, controls, electron 3263
 
  • M.J. Boland, R.T. Dowd, G. LeBlanc, M.J. Spencer, Y.E. Tan, A. Walsh
    ASP, Clayton, Victoria
  Two diagnostic beamlines have been designed and constructed for the Australian Synchrotron Storage Ring. One diagnostic beamline is a simple x-ray pinhole camera system, with a BESSY II style pinhole array, designed to measure the beam divergence, size and stability. The second diagnostic beamline uses an optical chicane to extract the visible light from the photon beam and transports it to various instruments. The end-station of the optical diagnostic beamline is equipped with a streak camera, a fast ICCD camera, a CCD camera and a fill pattern monitor. The beamline design and some commissioning measurements are presented.  
 
THPLS046 The Status of Instrumentation and Control for SSRF booster, linac, controls, storage-ring 3392
 
  • D.K. Liu
    SINAP, Shanghai
  The SSRF (Shanghai Synchrotron Radiation Facility) was started in December 25, 2004, and is located in the Zhang Jiang Hi-Teck park in Shanghai. During the past one year, the main structure is under construction and will be completed in the middle of next year on schedule. Various equipment is being processed and tested. The preliminary design of the control system, including various hardware and software, are completed, and some prototype of IOC with EPICS such as LINAC rf station, magnet station and beam diagnosis station, etc. have been already tested successfully. The digital power supply control will be adopted. Various beam instrumentation have been designed for diagnostics of the LINAC, booster and storage ring. The performance of the design, progress of the subsystem and preliminary test results of the prototype will be described in this paper in detail.  
 
THPLS094 First Measurement Results at the LEG Project's 100 keV DC Gun Test Stand emittance, gun, cathode, SNR 3499
 
  • S.C. Leemann, Å. Andersson, R. Ganter, V. Schlott, A. Streun, A.F. Wrulich
    PSI, Villigen
  The Low Emittance Gun Project (LEG) at PSI aims at developing a high-brightness, high-current electron source: a 20-fold improved brightness compared to present state-of-the-art electron guns. The source is intended to form the basis for a cost-efficient implementation of a high-power X-ray FEL light-source for scientific research at PSI. A field emitter array (FEA) cathode is being considered a source candidate. In order to study pulsed field emission from such a cathode and to investigate space charge compensation techniques as well as to develop diagnostic procedures to characterize the beam resulting from an FEA cathode, a 100 keV DC gun test stand has been built. The test stand gun and diagnostics have been modeled with the codes MAFIA and GPT. From extensive parameter studies an optimized design has been derived and construction of the gun and diagnostics have recently been completed. We report on the commissioning of the test stand and present first measurement results.  
 
THPLS105 Characterization of the SPARC Photo-injector with the Movable Emittance Meter emittance, cathode, laser, space-charge 3523
 
  • A. Cianchi, L. Catani, E. Chiadroni
    INFN-Roma II, Roma
  • M. Boscolo, M. Castellano, G. Di Pirro, M. Ferrario, D. Filippetto, V. Fusco, L. Palumbo, C. Vaccarezza
    INFN/LNF, Frascati (Roma)
  • P. Musumeci
    INFN-Roma, Roma
  As a first stage of the commissioning of SPARC accelerator a complete characterization of the photo-injector is planned. The objective is the optimization of the RF-gun setting that best matches the design working point and, generally, a detailed study of the emittance compensation process providing the optimal value of emittance at the end of the linac. For this purpose a novel beam diagnostic, the emittance-meter, consisting of a movable emittance measurement system, was conceived and built. This paper presents the results of the first measurements with the emittance-meter showing the characteristics and the performance at the SPARC photo-injector.  
 
FRYCPA01 ITER and International Scientific Collaboration plasma, controls, vacuum, site 3641
 
  • S. Chiocchio
    MPI/IPP, Garching
  The presentation will describe the status and perspectives of the ITER Project. It will also explore the possible connection between the accelerator and the fusion worlds. The talk will cover experience in the managerial and sociological aspects of the worldwide collaboration of which ITER is the end result, very similar to the issues facing the accelerator community, which also faces projects of similar scope from the point of view of time span, technical complexity and sociological impact.  
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