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diagnostics

Paper Title Other Keywords Page
MOOBC02 Experiments in Warm Dense Matter using an Ion Beam Driver target, ion, plasma, electron 140
 
  • F. M. Bieniosek
  • J. J. Barnard, M. Kireeff Covo, A. W. Molvik
    LLNL, Livermore, California
  • L. Grisham
    PPPL, Princeton, New Jersey
  • M. Leitner, B. G. Logan, R. More, P. N. Ni, P. K. Roy
    LBNL, Berkeley, California
  • H. Yoneda
    University of electro-communications, Tokyo
  Funding: Work performed under the auspices of the U. S. Dept. of Energy by LBNL, LLNL, and PPPL under Contracts No. W-7405-Eng-48, DE-AC02-05CH11231, and DE-AC02-76CH3073.

We describe near term heavy-ion beam-driven warm dense matter (WDM) experiments. Initial experiments are at low beam velocity, below the Bragg peak, increasing toward the Bragg peak in subsequent versions of the accelerator. The WDM conditions are envisioned to be achieved by combined longitudinal and transverse neutralized drift compression to provide a hot spot on the target with a beam spot size of about 1 mm, and pulse length about 1-2 ns. The range of the beams in solid matter targets is about 1 micron, which can be lengthened by using porous targets at reduced density. Initial candidate experiments include an experiment to study transient darkening in the WDM regime; and a thin target dE/dx experiment to study beam energy and charge state distribution in a heated target. Further experiments will explore target temperature and other properties such as electrical conductivity to investigate phase transitions and the critical point.

 
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MOPAN018 Performance of the New Coupled Bunch Feedback System at HERA-p feedback, controls, kicker, luminosity 185
 
  • M. G. Hoffmann
  • S. Choroba, F. Eints, U. Hurdelbrink, P. Morozov, Y. Nechaev, J. Randhahn, S. Ruzin, S. Simrock, V. Soloviev
    DESY, Hamburg
  A longitudinal broadband damper system to control coupled bunch instabilities (LMBF) has been installed in the 920~GeV proton accelereator HERA-p at the Deutsches Elektronen-Synchrotron DESY in Q4/2005. The Feedback system was fully automated, in order to relieve the operator from manual control during system operation. During comissioning in Q1/2006 it turned out that the performance goals were reached and the noise is not as much a problem as expected. The proton bunch length is significantly reduced as is the stretching of the bunches over runtime. Without additional damping the bunch length is about 1.5~ns (FWHM) at the beginning of a typical luminosity run. With the new feedback system in operation the bunch length could be decreased to 1.0 ns at best. Although the bunches get longer during the luminosity run, the integrated luminosity gain is thus up to 5%. System optimization points were found in automatic gain adjustment during acceleration ramp, oscillation level triggering and timing of kicker pulse to bunch. We describe the commissioning of the multibunch feedback system and the adjustment procedures. A performace overview after one year of operation is given.  
 
MOPAN020 Status of the Laser Master Oscillator System at FLASH laser, feedback, electron, controls 191
 
  • A. Winter
  • W. J. Jalmuzna
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw
  • F. Loehl, H. Schlarb, P. Schmuser
    DESY, Hamburg
  An optical synchronization system based on the timing-stabilized distribution of ultra-short optical pulses has been proposed for next generation light sources, e.g. the European XFEL. The concept will be implemented and tested at FLASH at DESY. This paper describes the status of the optical master oscillator, which consists of two mode-locked Erbium-doped fiber lasers running in parallel.  
 
MOPAN063 Extremely Low-jitter FPGA Based Synchronization Timing System controls, power-supply, gun, insertion 296
 
  • J. Dedic
  • D. Golob, A. Hasanovic, M. Plesko
    Cosylab, Ljubljana
  Injection-involved synchronization timing system must provide synchronization triggers and clocks with the jitter values in the range of few tens of ps. A well-thought-out system-level design approach was necessary, splitting a design into several sub-modules, each addressing the specific synchronization issue. Tight synchronization between the unrelated RF signal and external trigger is based on a PLL phase-shifted over-sampling technique. Beam-monitoring instrumentation synchronization is also handled. An emphasis was put into a design, offering an installation without calibration. Utilizing state-of-the art FPGA circuits we designed a purely digital system, without analogue components (i.e. delay lines) that would require a time-consuming calibration and lead to increasing jitter for long delay ranges. Finally, regardless of its complexity the timing solution has to provide seamless integration into the accelerator facility. To leverage the performance, offered by a dedicated state-of-the-art HW, with flexibility, offered by a SW solution, we used a standard device for peripheral CS integration, based on an embedded processor running OS - a part of a microIOC family of products.  
 
MOPAN069 Ultrasound Diagnostics of the Superconducting Cable Connections Between the Main Ring Magnets of LHC controls, superconducting-magnet, scattering, quadrupole 311
 
  • F. Caspers
  • T. Kroyer, J.-P. G. Tock, L. R. Williams
    CERN, Geneva
  • J. Kulka
    AGH, Cracow
  As part of the LHC assembly program, the super-conducting magnets are interconnected after installation. Electrical continuity between the magnets is ensured via a specifically designed cable splice box which allows the cables to be electrically joined by an automated low temperature brazing technique. The electrical resistance and mechanical strength of the cable junctions depend on the quality of the brazed joint. An ultrasound diagnostic of the brazed joint has been developed to accompany the visual inspection and reinforce the quality control process. Non-standard ultrasound diagnostic techniques, without using matching liquids or gel in the harsh and congested working environment, applied to the sandwich structure of the cable splice box, which presents high ultra-sonic losses due to multiple scattering, have been developed. The equipment and methods implemented are described in detail, together with results of quality control tests made in the production environment.  
 
MOPAN070 Developments in High-precision Aspects of Power Converter Control for LHC controls, shielding, target, monitoring 314
 
  • G. Fernqvist
  • M. C. Bastos, A. Cantone, Q. King
    CERN, Geneva
  The initial results from integration testing of the LHC magnet power converters revealed problems of low-frequency noise, settling time, drift with time and temperature, thermal management and EMC. These problems originated in the use of DSP, the A/D converter (ADC), the DC Current Transducer (DCCT) and their respective environments. This paper reports the methods used to improve the performance through hardware and software modifications and the results achieved.  
 
MOPAN112 Digital Control Interface for Bipolar Corrector Power Supplies for LCLS controls, power-supply, monitoring, feedback 428
 
  • S. Cohen
  • S. R. Babel
    Bira, Albuquerque, New Mexico
  We detail the development, testing and commissioning of a single-board digital interface for modular bipolar corrector magnet power supplies to installed at the Linac Coherent Light Source (LCLS) at the Stanford Linear Accelerator (SLAC). The sixteen-channel VME-form-factor board replaces the passive the control-interface board in the MCOR (Magnet Corrector) Chassis. The board is a self-contained system with both serial and Ethernet connectivity intended for use with an EPICS accelerator control system IOC, however, the ASCII protocol allows generic computer control. The interface card contains 16 independent ADC and DAC channels, each with 16 bits of resolution. Additionally, the interlock, fault, reset and digital control lines are remotely controllable via either the serial or Ethernet connections. The design has been planned so that a mini-IOC can be included on board for direct Channel Access connectivity.  
 
MOPAS052 The LANSCE Control System Current State and Upgrade Outlook controls, linac, instrumentation, monitoring 554
 
  • M. Pieck
  • E. Bjorklund, G. P. Carr, J. A. Faucett, J. O. Hill, D. M. Kerstiens, P. S. Marroquin, P. McGhee, M. A. Oothoudt, S. Schaller
    LANL, Los Alamos, New Mexico
  The LANSCE (Los Alamos Neutron Science Center) runs its LINAC control system based on 30(+) year old technology. While some peripheral upgrades have been made over the years, the control system will need some major improvements over the next five years in order to continue to support the user facility's mission. The proposed multi-million dollar LANSCE-R (Refurbishment) project creates a unique opportunity to upgrade the existing control system. We intend to use the EPICS (Experimental Physics and Industrial Control System) control system with the following goals for effective control at modest cost: (1) Replacing our VMS basedμVAX's; (2) Replacing the RICE (Remote Instrumentation and Control Equipment) subsystem with Programmable Logic Controllers (PLCs) to handle regular data acquisition and control, and custom hardware to handle "flavored" data acquisition; (3) Replacing the Master Timer subsystem with a modern event system; (4) Converting Fortran programs running on VAX/VMS computers to Java Programs running on Linux-based desktop PCs. The boundary condition, as usual, is that we must implement these major changes on a running accelerator.  
 
MOPAS070 The DC-Magnet Power Supplies for the LCLS Injector power-supply, controls, quadrupole, dipole 590
 
  • A. C. de Lira
  • P. Bellomo, K. Luchini, D. Macnair
    SLAC, Menlo Park, California
  Funding: This work was performed in support of the LCLS project at SLAC and funded by Department of Energy contract DE-AC02-76SF00515

The LCLS injector at SLAC requires 100+ dc-magnet power supply systems for its operation. Power supplies are divided into two main groups: intermediate rack-mounted type for output powers up to 20 kW at 375 A, and bipolar units rated 6 A, 12 A, and 30 A for corrector magnets and small quadrupoles. The intermediate power supplies are controlled by a 20-bit Ethernet power supply controller, specially developed at SLAC to be used in this project. The bipolar units are controlled via 12-bit DACs and ADCs housed in a VME crate. EPICS is the controls interface to all systems. For all systems, stability requirements are better than 1000 ppm. The Power Conversion Department at SLAC, in close cooperation with the LCLS Controls group, was responsible for defining the major characteristics of the power supply systems, their specification, procurement, installation, and commissioning. In this paper we describe the main characteristics of the power supply systems for the LCLS injector, including results from their successful commissioning early this year.

 
 
MOPAS098 Dynamic Collaborative Documentation at the Brookhaven National Laboratory Collider-Acclerator Department controls, site, background 658
 
  • J. Niedziela
  • W. Fu, M. Harvey, G. J. Marr, T. Satogata, V. Schoefer
    BNL, Upton, Long Island, New York
  Funding: The work was performed under the US Department of Energy Contract No. DE-AC02-98CH1-886, and with support of RIKEN(Japan) and Renaissance Technologies Corp.(USA)

Centralization of information pertaining to accelerators can benefit accelerator operation and development. Further, retention and the changeable nature of information present challenges to accelerator operation, particularly in instances of turnover. MediaWiki is free, server-based software licensed under the GNU General Public License that uses PHP to render data stored in a MySQL database as interactive web documents, and is designed to produce collaborative documentation. The MediaWiki engine was implemented at BNL, and this paper describes the first year of use by the Operations, Controls, and RF groups at the Collider-Accelerator Department, including code modifications, common practices, and the use of the wiki as a training tool.

 
 
TUODAB02 Electron Cloud Generation and Trapping in a Quadrupole Magnet at the LANL PSR electron, quadrupole, proton, beam-losses 828
 
  • R. J. Macek, M. J. Borden, A. A. Browman, R. J. Macek, R. C. McCrady, J. F. O'Hara, L. Rybarcyk, T. Spickermann, T. Zaugg
    LANL, Los Alamos, New Mexico
  • J. E. Ledford
    TechSource, Santa Fe, New Mexico
  • M. T.F. Pivi
    SLAC, Menlo Park, California
  Funding: Work supported by DOE SBIR Grant No. DE-FG02-04ER84105 and CRADA No. LA05C10535 between TechSource, Inc. and the Los Alamos National Laboratory.

Recent beam physics studies on the two-stream e-p instability at LANL proton storage ring (PSR) have focused on the role of the electron cloud generated in quadrupole magnets where electrons, which seed beam-induced multipacting, are expected to be largest due to grazing angle losses from the beam halo. A new diagnostic to measure electron cloud formation and trapping in a quadrupole magnet has been developed, installed, and successfully tested at PSR. Experimental results will be presented on various characteristics of electron cloud obtain from experiments using this diagnostic and compared with simulations. Results include data on flux and energy spectra of electrons striking the vacuum chamber, the line density and lifetime of electrons trapped in the quadrupole after the beam has been extracted as well as evidence regarding electrons ejected from the magnet during passage of the proton beam.

 
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TUPMN038 Coherent Cherenkov Radiation as a Temporal Diagnostic for Microbunched Beams radiation, photon, electron, vacuum 998
 
  • G. Gatti
  • A. M. Cook, J. B. Rosenzweig, R. Tikhoplav
    UCLA, Los Angeles, California
  Cherenkov radiation of a relativistic e-beam traversing a thin section of aerogel is analized, putting the stress on the coherent contribution due to the intra-beam, transverse and longitudinal structure. The use of this tool as a temporal diagnostic for micro-bunched beams makes possible to improve the amount of collected power at the microbunching frequency several orders of magnitude more respect to the uncoherent Cherenkov contribution. The non-idealities of a real beam are taken in account, and some techniques aimed on enhancing the coherent part of radiation are proposed and analized analitically and through simulation codes.  
 
TUPMN084 The Status of the Daresbury Energy Recovery Linac Prototype gun, linac, laser, electron 1106
 
  • S. L. Smith
  • N. Bliss
    STFC/DL, Daresbury, Warrington, Cheshire
  • A. R. Goulden, G. Priebe
    STFC/DL/SRD, Daresbury, Warrington, Cheshire
  • D. J. Holder, P. A. McIntosh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  As part of the UK's R&D programme to develop an advanced energy recovery linac-based light source (4GLS); a 35 MeV technology demonstrator called the Energy Recovery Linac Prototype (ERLP) has been constructed. It is based on a combination of a DC photocathode electron gun, a superconducting injector linac and main linac operating in energy recovery mode, driving an IR-FEL. The priorities for this machine are to gain experience of operating a photoinjector gun and superconducting linacs; to produce and maintain high-brightness electron beams; achieving energy recovery from an FEL-disrupted beam and studying important synchronisation issues. The current status of this project is presented, including construction and commissioning progress, including plans for the future exploitation of this scientific and technical R&D facility.  
 
TUPMN104 A Design Study for Photon Diagnostics for the APS Storage Ring Short-Pulse X-ray Source electron, photon, undulator, laser 1156
 
  • B. X. Yang
  • E. M. Dufresne, E. C. Landahl, A. H. Lumpkin
    ANL, Argonne, Illinois
  Funding: Work supported by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

A short x-ray pulse source based on the crab cavity scheme proposed by Zholents* is being developed at the Advanced Photon Source (APS). Photon diagnostics that visualizes the electron bunches with transverse momentum chirp and verifies the performance of the short x-ray pulse is required. We present a design study for the imaging diagnostics inside and outside of the crab cavity zone, utilizing both x-ray and visible synchrotron radiation. Several design options of monochromatic and polychromatic x-ray optics will be explored for their compatibility with the short-pulse source. The diagnostics outside of the crab cavity zone will be used to map out stable operation parameters of the storage ring with crab cavities, and to perform single-bunch single-pass imaging of the chirped bunch, which facilitates the tuning of the crab cavity rf phase and amplitude so the performance of the short pulse source can be optimized while other users around the ring will not be disturbed.

* A. Zholents et al., NIM A 425, 385 (1999).

 
 
TUPMS033 Chicane Radiation Measurements with a Compressed Electron Beam at the BNL ATF radiation, electron, dipole, polarization 1254
 
  • G. Andonian
  • R. B. Agustsson, A. M. Cook, M. P. Dunning, E. Hemsing, A. Y. Murokh, S. Reiche, J. B. Rosenzweig
    UCLA, Los Angeles, California
  • M. Babzien, K. Kusche, R. Malone, V. Yakimenko
    BNL, Upton, Long Island, New York
  The radiation emitted from a chicane compressor has been studied at the Brookhaven National Laboratory (BNL) Accelerator Test Facility (ATF). Coherent edge radiation (CER)is emitted from a compressed electron beam as it traverses sharp edge regions of a magnet. The compression is accompanied by strong self-fields, which are manifested as distortions in the momentum space called beam bifurcation. Recent measurements indicate that the bunch length is approximately 100 fs rms. The emitted THz chicane radiation displays strong signatures of CER. This paper reports on the experimental characterization and subsequent analysis of the chicane radiation measurements at the BNL ATF with a discussion of diagnostics development and implementation. The characterization includes spectral analysis, far-field intensity distribution, and polarization effects. Experimental data is benchmarked to a custom developed start-to-end simulation suite.  
 
TUPMS046 Integration of the Optical Replica Ultrashort Electron Bunch Diagnostics with the Current-Enhanced SASE in the LCLS electron, laser, radiation, wiggler 1293
 
  • Y. T. Ding
  • P. Emma, Z. Huang
    SLAC, Menlo Park, California
  In this paper, we present a feasibility study of integrating the optical replica (OR) ultrashort electron bunch diagnostics * with the current-enhanced SASE (ESASE) scheme ** in the LCLS. Both techniques involve using an external laser to energy-modulate the electron beam in a short wiggler and converting the energy modulation to a density modulation in a dispersive section. While ESASE proposes to use the high-current spikes to enhance the FEL signal, the OR method extracts the optical coherent radiation produced by a density modulated electron beam for frequency resolved optical gating (FROG) diagnostics. We discuss the optimization studies of combining the OR method with the ESASE after the second bunch compressor in the LCLS. Simulation results show that the OR method is capable of reproducing the expected double-horn current profile of a 200-fs bunch. The possibilities and limitations of reconstructing the longitudinal phase space profile are also explored.

* E. Saldin et al, Nucl. Instr. and Meth. A 539, 499 (2005).** A. Zholents, Phys. Rev. ST Accel. Beams 8, 040701 (2005); A. Zholents et al., in Proceedings of FEL2004, 582 (2004).

 
 
TUPMS076 Status of R&D Energy Recovery Linac at Brookhaven National Laboratory linac, gun, controls, power-supply 1347
 
  • V. Litvinenko
  • J. Alduino, D. Beavis, I. Ben-Zvi, M. Blaskiewicz, J. M. Brennan, A. Burrill, R. Calaga, P. Cameron, X. Chang, K. A. Drees, G. Ganetis, D. M. Gassner, J. G. Grimes, H. Hahn, L. R. Hammons, A. Hershcovitch, H.-C. Hseuh, A. K. Jain, D. Kayran, J. Kewisch, R. F. Lambiase, D. L. Lederle, C. Longo, G. J. Mahler, G. T. McIntyre, W. Meng, T. C. Nehring, B. Oerter, C. Pai, D. Pate, D. Phillips, E. Pozdeyev, T. Rao, J. Reich, T. Roser, T. Russo, Z. Segalov, J. Smedley, K. Smith, J. E. Tuozzolo, G. Wang, D. Weiss, N. Williams, Q. Wu, K. Yip, A. Zaltsman
    BNL, Upton, Long Island, New York
  • H. Bluem, M. D. Cole, A. J. Favale, D. Holmes, J. Rathke, T. Schultheiss, A. M.M. Todd
    AES, Princeton, New Jersey
  • B. W. Buckley
    CLASSE, Ithaca
  • G. Citver
    Stony Brook University, StonyBrook
  • J. R. Delayen, L. W. Funk, H. L. Phillips, J. P. Preble
    Jefferson Lab, Newport News, Virginia
  Funding: Work performed under the auspices of the U. S. Department of Energy and partially funded by the US Department of Defence.

In this paper we present status and plans for the 20-MeV R&D energy recovery linac, which is under construction at Collider Accelerator Department at BNL. The facility is based on high current (up to 0.5 A of average current) super-conducting 2.5 MeV RF gun, single-mode super-conducting 5-cell RF linac and about 20-m long return loop with very flexible lattice. The R&D ERL, which is planned for commissioning in 2008, aims to address many outstanding questions relevant for high current, high brightness energy-recovery linacs.

 
 
TUPAN003 Beam Quality and Operational Experience with the Superconducting LINAC at the ISAC II RIB facility linac, emittance, ion, acceleration 1392
 
  • M. Marchetto
  • R. E. Laxdal, V. Zviagintsev
    TRIUMF, Vancouver
  The ISAC II superconducting LINAC is now in the operational phase. The linac was commissioned with stable beams from an off-line source. The commissioning not only proved the integrity of the infrastructure but benchmarked the beam quality and rf cavity performance. Measurements of the transverse and longitudinal emittance are consistent with little or no emittance growth through the acceleration. Transmission near 100% has been achieved though some solenoid steering is evident due to misalignment. The misalignment problem is being evaluated using the beam as diagnostic tool while applying corrections based on the beam measurements. The effectiveness of the corrections will be reported. The machine has been demonstrated to be easy to tune, reliable in restoring beam and flexible enough to accommodate different tuning strategies; software routines have been developed in order to facilitate the tuning process. In this paper the operational routine for tuning and beam delivery will be presented as well as the beam characteristics drawn from the commissioning studies.  
 
TUPAN011 Beam Operation of the SARAF Light Ion Injector rfq, ion, ion-source, proton 1410
 
  • C. Piel
  • K. Dunkel, M. Pekeler, H. Vogel, P. vom Stein
    ACCEL, Bergisch Gladbach
  In beginning of 2007 the installation of the first stage of SARAF has been finalized. The system consists out of an ECR ion source, a low energy beam transport system, a four rod RFQ, a medium energy transport system and a superconducting module housing 6 half resonators and three superconducting solenoids. This injector will be characterized with a diagnostic plate. The installation allows continuous measurement of beam charge, position and phase. The diagnostic plate in addition provides a beam halo monitor, vertical and horizontal slit and wire systems, a slow and a fast faraday cup, which can only be used in pulsed operation. The paper will describe the status of commissioning, including results of the site acceptance test of major components.  
 
TUPAS030 Electron Cooling Rates Characterization at Fermilab's Recycler antiproton, electron, emittance, injection 1715
 
  • L. R. Prost
  • A. V. Shemyakin
    Fermilab, Batavia, Illinois
  Funding: Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy.

A 0.1 A, 4.3 MeV DC electron beam is routinely used to cool 8 GeV antiprotons in Fermilab's Recycler storage ring. While the primary function of the electron cooler is to increase the longitudinal phase-space density of the antiprotons, significant transverse cooling rates have been observed as well. Numerical characterization of electron cooling is done by two types of measurements: friction force measurements by the voltage jump method and diffusion/cooling rates measurements. The paper will present the recent measurement results and will compare them to a non-magnetized model.

 
 
WEOBKI02 Evolution of Relativistic Plasma Wave-Front in LWFA plasma, electron, laser, scattering 1919
 
  • C. E. Clayton
  • F. Fang, C. Joshi, K. A. Marsh, A. E. Pak, J. E. Ralph
    UCLA, Los Angeles, California
  • N. C. Lopes
    Instituto Superior Tecnico, Lisbon
  Funding: Work supported by DOE Grant Nos. DE-FG52-03NA00138 and DE-FG02-92ER40727, and Grant POCI/FIS/58776/2004 (FCT-Portugal)

In a laser wakefield accelerator experiment where the length of the pump laser pulse is several plasma period long, the leading edge of the laser pulse undergoes frequency downshifting as the laser energy is transferred to the wake. Therefore, after some propagation distance, the group velocity of the leading edge of of the pump pulse–and therefore of the driven electron plasma wave–will slow down. This can have implications for the dephasing length of the accelerated electrons and therefore needs to be understood experimentally. We have carried out an experimental investigation where we have measured the velocity vf of the 'wave-front' of the plasma wave driven by a nominally 50fs (FWHM), intense (a0~1), 0.8 micron laser pulse. To determine the speed of the wave front, time- and space-resolved shadowgraphy, interferometry, and Thomson scattering were used. Although low density data (ne ~ 1018 cm-3) showed no significant changes in vf over 1.5mm (and no accelerated electrons), high-density data shows accelerated electrons and an approximately 5% drop in vf after a propagation distance of about 800 microns.

 
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WEOCAB01 Design of the Beam Delivery System for the International Linear Collider collimation, linac, extraction, betatron 1985
 
  • A. Seryi
  • I. V. Agapov, G. A. Blair, S. T. Boogert, J. Carter
    Royal Holloway, University of London, Surrey
  • M. Alabau, P. Bambade, J. Brossard, O. Dadoun
    LAL, Orsay
  • J. A. Amann, R. Arnold, F. Asiri, K. L.F. Bane, P. Bellomo, E. Doyle, A. F. Fasso, L. Keller, J. Kim, K. Ko, Z. Li, T. W. Markiewicz, T. V.M. Maruyama, K. C. Moffeit, S. Molloy, Y. Nosochkov, N. Phinney, T. O. Raubenheimer, S. Seletskiy, S. Smith, C. M. Spencer, P. Tenenbaum, D. R. Walz, G. R. White, M. Woodley, M. Woods, L. Xiao
    SLAC, Menlo Park, California
  • M. Anerella, A. K. Jain, A. Marone, B. Parker
    BNL, Upton, Long Island, New York
  • D. A.-K. Angal-Kalinin, C. D. Beard, J.-L. Fernandez-Hernando, P. Goudket, F. Jackson, J. K. Jones, A. Kalinin, P. A. McIntosh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • R. Appleby
    UMAN, Manchester
  • J. L. Baldy, D. Schulte
    CERN, Geneva
  • L. Bellantoni, A. I. Drozhdin, V. S. Kashikhin, V. Kuchler, T. Lackowski, N. V. Mokhov, N. Nakao, T. Peterson, M. C. Ross, S. I. Striganov, J. C. Tompkins, M. Wendt, X. Yang
    Fermilab, Batavia, Illinois
  • K. Buesser
    DESY, Hamburg
  • P. Burrows, G. B. Christian, C. I. Clarke, A. F. Hartin
    OXFORDphysics, Oxford, Oxon
  • G. Burt, A. C. Dexter
    Cockcroft Institute, Warrington, Cheshire
  • J. Carwardine, C. W. Saunders
    ANL, Argonne, Illinois
  • B. Constance, H. Dabiri Khah, C. Perry, C. Swinson
    JAI, Oxford
  • O. Delferriere, O. Napoly, J. Payet, D. Uriot
    CEA, Gif-sur-Yvette
  • C. J. Densham, R. J.S. Greenhalgh
    STFC/RAL, Chilton, Didcot, Oxon
  • A. Enomoto, S. Kuroda, T. Okugi, T. Sanami, Y. Suetsugu, T. Tauchi
    KEK, Ibaraki
  • A. Ferrari
    UU/ISV, Uppsala
  • J. Gronberg
    LLNL, Livermore, California
  • Y. Iwashita
    Kyoto ICR, Uji, Kyoto
  • W. Lohmann
    DESY Zeuthen, Zeuthen
  • L. Ma
    STFC/DL, Daresbury, Warrington, Cheshire
  • T. M. Mattison
    UBC, Vancouver, B. C.
  • T. S. Sanuki
    University of Tokyo, Tokyo
  • V. I. Telnov
    BINP SB RAS, Novosibirsk
  • E. T. Torrence
    University of Oregon, Eugene, Oregon
  • D. Warner
    Colorado University at Boulder, Boulder, Colorado
  • N. K. Watson
    Birmingham University, Birmingham
  • H. Y. Yamamoto
    Tohoku University, Sendai
  The beam delivery system for the linear collider focuses beams to nanometer sizes at the interaction point, collimates the beam halo to provide acceptable background in the detector and has a provision for state-of-the art beam instrumentation in order to reach the physics goals. The beam delivery system of the International Linear Collider has undergone several configuration changes recently. This paper describes the design details and status of the baseline configuration considered for the reference design.  
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WEOCC02 Overview of warm-dense-matter experiments with intense heavy ion beams at GSI-Darmstadt target, ion, heavy-ion, laser 2038
 
  • P. N. Ni
  • J. J. Barnard
    LLNL, Livermore, California
  • F. M. Bieniosek, M. Leitner, B. G. Logan, R. More, P. K. Roy
    LBNL, Berkeley, California
  • A. Fernengel, A. Menzel
    TU Darmstadt, Darmstadt
  • A. Fertman, A. Golubev, B. Y. Sharkov, I. Turtikov
    ITEP, Moscow
  • D. Hoffmann, A. Hug, N. A. Tahir, A. Udrea, D. Varentsov
    GSI, Darmstadt
  • M. Kulish, D. Nikolaev, A. Ternovoy
    IPCP, Chernogolovka, Moscow region
  Recently, a series of high energy density (HED) physics experiments with heavy ion beams have been carried out at the GSI heavy ion accelerator. The ion beam spot of heating uranium beam size of about 1 mm, pulse length about 120 ns and intensity 109 particles/bunch. In these experiments, metallic solid and porous targets of macroscopic volumes were heated by intense heavy ion beams uniformly and quasi-isochorically, and temperature, pressure and expansion velocity were measured during the heating and cooling of the sample using a fast multi-channel radiation pyrometer, laser Doppler interferometer (VISAR), Michelson displacement interferometer and streak-camera-based-backlighting system. In the performed experiments target temperatures varying from 1'000 K to 12'000 K and pressure in kbar range were measured. Expansion velocities up to 2600 m/s have been registered for lead and up to 1700 m/s for tungsten targets.  
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WEPMN021 High Pressure Rinsing System Comparison target 2092
 
  • D. Sertore
  • G. Ciovati, T. M. Rothgeb
    Jefferson Lab, Newport News, Virginia
  • M. Fusetti, P. Michelato, C. Pagani
    INFN/LASA, Segrate (MI)
  • T. Higo, J. H. Hong, K. Saito
    KEK, Ibaraki
  High pressure rinsing (HPR) is a key process for the surface preparation of high field superconducting cavities. A portable apparatus for the water jet characterization, based on the transferred momentum between the water jet and a load cell, has been used in different laboratories. This apparatus allows to collected quantitative parameters that characterize the HPR water jet. In this paper, we present a quantitative comparison of the different water jet produced by various nozzles routinely used in different laboratories for the HPR process  
 
WEPMN112 Multichannel Vector Field Control Module for LLRF Control of Superconducting Cavities controls, klystron, feedback, impedance 2298
 
  • P. Varghese
  • B. Barnes, J. Branlard, B. Chase, P. W. Joireman, D. W. Klepec, U. Mavric, V. Tupikov
    Fermilab, Batavia, Illinois
  The field control of multiple superconducting RF cavities with a single Klystron, such as the proposed RF scheme for the ILC, requires high density (number of RF channels) signal processing hardware so that vector control may be implemented with minimum group delay. The MFC (Multichannel Field Control) module is a 33-channel, FPGA based downconversion and signal processing board in a single VXI slot, with 4 channels of high speed DAC outputs. An LO input of upto 1.6 GHz can be divided down to provide 8 clock signals through a clock distribution chip. A 32-bit, 400MHz floating point DSP provides additional computational capability for calibration and implementation of more complex control algorithms. Both the FPGA and DSP have external SDRAM memory for diagnostic data and nonvolatile Flash memory for program and configuration storage. Multiple high speed serial transceivers on the front panel and the backplane bus allow a flexible architecture for inter-module real time data exchanges. An interface CPLD supports the VXI bus protocol for communication to a Slot0 CPU, with Ethernet connections for remote in system programming of the FPGA and DSP as well as for data acquisition.  
 
WEPMS004 Deflecting Cavity for Beam Diagnostics in ERL Injector impedance, gun, emittance, electromagnetic-fields 2331
 
  • S. A. Belomestnykh
  • V. D. Shemelin, K. W. Smolenski, V. Veshcherevich
    CLASSE, Ithaca
  Funding: Work is supported by the National Science Foundation grant PHY 0131508.

A 1300 MHz deflecting cavity will be used for beam slice emittance measurements, and to study the temporal response of negative electron affinity photocathodes in the ERL injector currently under construction at Cornell University. A single-cell TM110-mode cavity was designed to deflect the beam vertically. The paper describes the cavity shape optimization procedure, its mechanical design and performance at low RF power.

 
 
WEPMS031 Development of a Temperature Mapping System for 1.3-GHz 9-Cell SRF Cavities superconductivity, radio-frequency, linear-collider, collider 2406
 
  • A. Canabal
  • J. D. Bowyer
    NMSU, Las Cruces, New Mexico
  • P. Chacon, N. A. Gillespie, M. A. Madrid, T. Tajima
    LANL, Los Alamos, New Mexico
  The mapping of outer wall temperature during the vertical test of a superconducting radio-frequency (SRF) cavity has been one of the most useful tools to detect bad spots of the cavity. However, few systems except a rotating-arm type one have been developed so far for 9-cell cavities. Since it will be an essential tool to identify the failure of the cavities, we started to develop a fix-type temperature mapping system that will enable us to map the temperature of 9-cell cavities in a much shorter time than rotating-arm type. This paper describes the design, status of the development and hopefully some results of the mapping of actual cavities.  
 
THOBAB01 EMMA - the World's First Non-scaling FFAG acceleration, extraction, injection, factory 2624
 
  • T. R. Edgecock
  EMMA - the Electron Model of Muon Acceleration - is to be built at the CCLRC Daresbury Laboratory in the UK. It will demonstrate the principle of non-scaling FFAGs and be used to study the features of this type of accelerator in detail. Although a model of the muon accelerators in a Neutrino Factory, EMMA will have sufficient flexibility to study a variety of applications. It has been designed by an international collaboration of accelerator physicists and will be built as part of the CONFORM project using funds recently approved in the UK.  
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THXC02 Diagnostics for Commissioning LCLS emittance, monitoring, linac, radiation 2635
 
  • P. Krejcik
  The fist stage of commissioning of the Linac Coherent Light Source at SLAC has begun in April of this year with succesful transport of the beam from the new RF photoinjector throught to the first bunch compressor. Construction and installation is continuing and will culminate with first FEL light in 2009. The LCLS provides several diagnostic challenges for providing precision, single-pulse readback of beam size and position in order to tune for very low 1 micron emittances. Ultra-short subpicosecond bunches call for special techniques of bunch length measurement including coherent radiation monitoring and the transverse deflecting cavity. The latter is also used to measure time dependant emittance and energy spread of slices along the bunch, which are critical to the lasing process within the FEL.  
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THOAC04 RMS Emittance Measurements Using Optical Transition Radiation Interferometry at the Jefferson Lab FEL electron, emittance, radiation, linac 2645
 
  • M. A. Holloway
  • S. V. Benson, W. Brock, J. L. Coleman, D. Douglas, R. Evans, P. Evtushenko, K. Jordan, D. W. Sexton
    Jefferson Lab, Newport News, Virginia
  • R. B. Fiorito, P. G. O'Shea, A. G. Shkvarunets
    UMD, College Park, Maryland
  Funding: Office of Naval Research Joint Technology Office

Optical Transition Radiation Interferometry (OTRI) has proven to be effective tool for measuring rms beam divergence. We present rms emittance measurement results of the 115 MeV energy recovery linac at the Thomas Jefferson National Laboratories Free electron Laser using OTRI. OTRI data from both near field beam images and far field angular distribution images give evidence of two spatial and angular distributions within the beam. Using the unique features of OTRI we segregate the two distributions of the beam and estimate separate rms emittance values for each component.

 
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THYC02 Coherent Radiation Diagnostics for Short Bunches radiation, synchrotron, synchrotron-radiation, electron 2653
 
  • O. Grimm
  Electron bunches less than a few picoseconds emit lots of coherent radiation (CSR, CTR, CDR, etc.) most of which is at terahertz frequencies. This is becoming the diagnostic of choice for bunch compressors in linacs (chicanes). However, at these frequencies the transmission of the radiation can be very challenging. Signifiicant advances, with examples of real measurements at TTF2, will be described.  
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THOBC01 Status of Various SNS Diagnostic Systems target, beam-losses, pick-up, instrumentation 2658
 
  • W. Blokland
  • J. G. Patton, T. A. Pelaia, T. R. Pennisi, J. D. Purcell, M. Sundaram
    ORNL, Oak Ridge, Tennessee
  Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U. S. Department of Energy under contract DE-AC05-00OR22725

The Spallation Neutron Source (SNS) accelerator systems are ramping up to deliver a 1.0 GeV, 1.4 MW proton beam to a liquid mercury target for neutron scattering research. Enhancements or additions have been made to several diagnostics instruments to support the ramp up in intensity, improve reliability, and/or add functionality. The Beam Current Monitors now support increased rep rates, the Harp system now includes charge density calculations for the target, and a new system has been created to collect data for the beam accounting and present the data over the web and to the operator consoles. Many of the instruments are PC-based and a way to manage their instrument configuration files through the Oracle database has been implemented. A new version for the wire scanner software has been developed and is under test. This paper also includes data from the various instruments.

 
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THPMN014 Commissioning of the Linac for the Heidelberg Heavy Ion Cancer Therapy Centre (HIT) rfq, linac, ion, synchrotron 2734
 
  • M. T. Maier
  • W. Barth, W. B. Bayer, L. A. Dahl, L. Groening, C. M. Kleffner, B. Schlitt, K. Tinschert, H. Vormann, S. Yaramyshev
    GSI, Darmstadt
  • U. Ratzinger, A. Schempp
    IAP, Frankfurt am Main
  A clinical facility for cancer therapy using energetic proton and ion beams (C, He and O) is under construction and will be installed at the Radiologische Universitätsklinik in Heidelberg, Germany. It consists of two ECR ion sources, a 7 MeV/u linac injector, and a 6.5 Tm synchrotron to accelerate the ions to final energies of 50-430 MeV/u. The linac comprises a 400 keV/u RFQ and a 7 MeV/u IH-DTL operating at 216.8 MHz. The commissioning of the linac with beam was performed in three steps for the LEBT, the RFQ, and the IH-DTL. For this purpose a versatile beam diagnostic test bench has been used consisting of a slit-grid emittance measurement device, transverse pick-ups providing for time of flight energy measurements, SEM-profile grids, and different devices for beam current measurements. In this contribution the procedure and the results of the successful commissioning in the year 2006 of the linear accelerator are reported.  
 
THPMN085 Proposed Dark Current Studies at the Argonne Wakefield Accelerator Facility cathode, laser, gun, electron 2904
 
  • S. P. Antipov
  • M. E. Conde, W. Gai, J. G. Power, Z. M. Yusof
    ANL, Argonne, Illinois
  • V. A. Dolgashev
    SLAC, Menlo Park, California
  • L. K. Spentzouris
    Illinois Institute of Technology, Chicago, Illinois
  Funding: US Department of Energy

A study of breakdown mechanism has been initiated at the Argonne Wakefield Accelerator Facility (AWA). Breakdown may include several factors such as local field enhancement, explosive electron emission, Ohmic heating, tensile stress produced by electric field, and others. The AWA is building a dedicated facility to test various models for breakdown mechanisms and to determine the roles of different factors in the breakdown. An imaging system is being put together to identify single emitters on the cathode surface. This will allow us to study dark current properties in the gun. We also plan to trigger breakdown events with a high-powered laser at various wavelengths (IR to UV). Another experimental idea follows from the recent work on a Schottky-enabled photoemission in an RF photoinjector that allows us to determine in situ the field enhancement factor on a cathode surface. Monitoring the field enhancement factor before and after can shed some light on a modification of metal surface after the breakdown.

 
 
THPMN099 Plans for a 750 MeV Electron Beam Test Facility at Fermilab acceleration, gun, electron, controls 2942
 
  • M. Church
  • S. Nagaitsev, P. Piot
    Fermilab, Batavia, Illinois
  A 750 MeV electron beam test facility at Fermilab is in the planning and early construction phase. An existing building is being converted for this facility. The photoinjector currently in use at the Fermilab NICADD Photoinjector Laboratory (FNPL) will be moved to the new facility and upgraded to serve as an injector for a beam acceleration section consisting of 3 Tesla or ILC-type cryomodules. A low energy off-axis beam will be constructed to test ILC crab cavity designs and provide opportunities for other tests. Downstream beamlines will consist of a diagnostic section, a beam test area for additional beam experiments, and a high power beam dump. The initial program for this facility will concentrate on testing ILC-type cryomodules and RF control with full ILC beam intensity. A future building expansion will open up further possibiliities for beam physics and beam technology experiments.  
 
THPMS016 A Large-Format Imaging Optics System for Fast Neutron Radiography optics, focusing, target, electron 3029
 
  • B. Rusnak
  • P. Fitsos, M. Hall, M. Jong, R. Souza
    LLNL, Livermore, California
  Funding: This work was performed under the auspices of the U. S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.

As part of the ongoing development of fast neutron imaging technology for national secu-rity applications at LLNL, a large-format imaging optics system has been designed and built. The system will be used to acquire radiographic images of heavily-shielded low-Z objects irradiated by ~ 10 MeV neutrons and is expected to have an ultimate spatial resolution ~ 1 mm (FWHM). It is comprised of a 65 cm x 65 cm plastic scintillator (e.g. BC-408), an aluminized front-surface turning mirror and a fast (~ f/1.25) optical lens coupled to a CCD camera body with a cryo-cooled, back-illuminated 4096 x 4096 (15 micron) pixel sensor. The lens and camera were developed and purchased from vendors and system integration was done at LLNL. A description of the overall system and its initial performance characteristics shall be presented.

 
 
THPMS024 Experimental Investigation of Self-guiding using a Matched Laser Beam in a cm Scale Length Underdense Plasma plasma, laser, electron, simulation 3052
 
  • J. E. Ralph
  • C. E. Clayton, F. Fang, C. Joshi, K. A. Marsh, A. E. Pak
    UCLA, Los Angeles, California
  Funding: This work was supported by NNSA Grant no. DE-FG52- 03NA00138, and DOE Grant no. DE-FG02-92ER40727.

High-intensity short-pulse laser guiding in plasma channels has extended the length over which acceleration occurs in laser wake field accelerators*. Recent multidimensional nonlinear plasma wave theory predicts a range of optimal characteristics for self-guiding of laser pulses in the blowout regime for pulses shorter than a plasma wavelength**. This theory predicts a robust, stable parameter space for self-guiding and wake production and has been verified through multidimensional particle-in-cell simulations. We experimentally explore the plasma dynamics and laser pulse propagation using a 50 fs multi-terawatt Ti:Sapphire laser in a helium plasma at plasma densities, laser powers, and spot sizes within this parameter space. Our parameters are in the range where the plasma is underdense and the laser power is much greater than the critical power for self focusing. The evolution of the laser pulse and plasma channel will be followed over several Rayleigh lengths.

* C. Geddes et. al., Nature (London) 431, 538 (2004)** W. Lu et. al., Phys. Plasmas 13, 056709 (2006)

 
 
THPMS068 Systems Testing of a Free Hg Jet System for Use in a High-Power Target Experiment target, proton, laser, factory 3136
 
  • V. B. Graves
  • A. J. Carroll, P. T. Spampinato
    ORNL, Oak Ridge, Tennessee
  • I. Efthymiopoulos, A. Fabich
    CERN, Geneva
  • H. G. Kirk, H. Park, T. Tsang
    BNL, Upton, Long Island, New York
  • K. T. McDonald
    PU, Princeton, New Jersey
  • P. Titus
    MIT/PSFC, Cambridge, Massachusetts
  Funding: U. S. Deparment of Energy contract DE-AC05-00OR22725

The design and operational testing of a mercury jet delivery system is presented. The equipment is part of the Mercury Intense Target (MERIT) Experiment, which is a proof-of-principle experiment to be conducted at CERN in the summer of 2007 to determine the feasibility of using an unconstrained jet of mercury as a target in a Neutrino Factory or Muon Collider. The Hg system is capable of producing a 1 cm diameter, 20 m/s jet of Hg inside a high-field solenoid magnet. A high-speed optical diagnostic system allows observation of the interaction of the jet with a 24 GeV proton beam. Performance of the Hg system will be presented, along with results of integrated systems testing without a beam.

 
 
THPMS079 Nonlinear Permittivity Effects in Dielectric Accelerating Structures controls, acceleration, linac, simulation 3169
 
  • P. Schoessow
  • A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio
  • V. P. Yakovlev
    Omega-P, Inc., New Haven, Connecticut
  Funding: Work supported by the US Department of Energy

New low loss ferroelectric ceramic materials* possessing large variations in the permittivity as a function of the electric field present interesting and potentially useful applications for dielectric loaded accelerating structures, both wakefield-based and driven by an external rf source. We will consider X-band cylindrical dielectric structures and report numerical results on frequency multiplication, wave steepening and shock formation, and the effect of nonlinearities on the mode structure of these devices. We will examine applications of nonlinear dielectric devices to high gradient acceleration, rf sources, and beam diagnostics.

* ''Fast Switching Ferroelectric Materials for Accelerator Applications'', A. Kanareykin et al., Proceedings of Advanced Accelerator Concepts 2006 (in press)

 
 
THPAN013 Computer-assisted Electron Beam Characterization at AIRIX Facility electron, cathode, beam-transport, extraction 3250
 
  • O. Mouton
  • M. Caron, F. Cartier, D. Collignon, G. Grandpierre, D. Guilhem, L. Hourdin, M. Mouillet, C. Noel, D. Paradis, O. Pierret
    CEA, Pontfaverger-Moronvilliers
  AIRIX is a high current accelerator designed for flash X-ray radiography. The electron beam produced into a vacuum diode (2 kA, 3.5 to 3.8 MV, 60 ns) is extracted from a velvet cold cathode. For a complete beam characterisation at the diode output the following set of data is required: the primary beam current intensity, the primary beam energy, the 2D mean beam divergence, the 2D RMS beam size as well as the 2D transverse beam emittance. Part of these parameters is experimentally given by electrical sensors located into the beam line (I), by time resolved energy spread measurements (E) as well as by a classical beam imaging set-up (XRMS, YRMS). Unfortunately, XRMS and YRMS are measured downstream the diode output. Therefore, in order to get the relevant beam parameters at the right location (diode output) numerical data treatments are required. The TRAJENV beam transport code, coupled with the MINUIT minimization library, computes the unknown beam parameters at the diode output. In this paper, we propose to describe both experimental and theoretical approaches leading to the full beam characterization at the diode output.  
 
THPAN032 Study of the Beam Dynamics in a Linac with the Code RETAR acceleration, electron, radiation, emittance 3298
 
  • A. R. Rossi
  • A. Bacci, C. Maroli, L. Serafini
    INFN-Milano, Milano
  • V. Petrillo
    Universita' degli Studi di Milano, Milano
  The three-dimensional fully relativistic and self-consistent code RETAR has been applied to model the dynamics of high-brightness electron beams and in particular to assess the importance of the retarded radiative part of the emitted electromagnetic fields in all conditions where the electrons experience strong accelerations. In this analysis we evaluate the radiative energy losses in the electron emission process from the photocathode of an injector, during the successive acceleration of the electron beam in the RF cavity and the focalization due to the magnetic field of the solenoid, taking also into account the e.m. field of the laser illuminating the cathode and the inhomogeneities on the cathode surface. The analysis is specifically carried out with parameters of importance in the framework of the SPARC and PLASMONX projects.  
 
THPAS008 Simulation of the Dynamics of Microwave Transmission Through an Electron Cloud electron, simulation, plasma, polarization 3525
 
  • K. G. Sonnad
  • J. R. Cary
    CIPS, Boulder, Colorado
  • M. A. Furman
    LBNL, Berkeley, California
  • P. Stoltz, S. A. Veitzer
    Tech-X, Boulder, Colorado
  Funding: Work supported by the U. S. DOE under Contract no. DE-AC02-05CH11231

Simulation studies are under way to analyze the dynamics of microwave transmission through a beam channel containing electron clouds. Such an interaction is expected to produce a shift in phase accompanied by attenuation in the amplitude of the microwave radiation. Experimental observation of these phenomena would lead to a useful diagnosis tool for electron clouds. This technique has already been studied* at the CERN SPS. Similar experiments are being proposed at the PEP-II LER at SLAC as well as the Fermilab MI. In this study, simulation results will be presented for a number of cases including those representative of the above mentioned experiments. The code VORPAL is being utilized to perform electromagnetic particle-in-cell (PIC) calculations. The results are expected to provide guidance to the above mentioned experiments as well as lead to a better understanding of the problem.

* T. Kroyer, F. Caspers, E. Mahner , pg 2212 Proc. PAC 2005, Knoxville, TN

 
 
THPAS034 Fast Imaging of Time-dependent Distributions of Intense Electron Beams electron, space-charge, gun, coupling 3573
 
  • K. Tian
  • G. Bai, B. L. Beaudoin, D. W. Feldman, R. B. Fiorito, I. Haber, R. A. Kishek, P. G. O'Shea, M. Reiser, D. Stratakis, D. F. Sutter, J. C.T. Thangaraj, M. Walter, C. Wu
    UMD, College Park, Maryland
  Funding: Work supported by the U. S. Department of Energy, the Office of Naval Research and the Joint Technology Office

Longitudinal perturbations can be generated in the space-charge dominated regimes in which most beams of interest are born. To study the modification of transverse beam distributions by longitudinal beam dynamics, we have conducted experimental studies using low energy electron beams by taking time resolved images of a beam with longitudinal density perturbations. Two different diagnostics are used: optical transition radiation (OTR) produced from an intercepting silicon based aluminum screen and a fast (<5ns decay time) phosphor screen. It is found that the beam is significantly affected by the perturbation. However the OTR signal is very weak and requires over 45 minutes of frame integration. The fast phosphor screen has much better sensitivity (~1'000 times enhancement). In this paper, we also report on the time resolved measurement of a parabolic beam, showing interesting correlations between transverse and longitudinal distributions of the beam.

 
 
THPAS050 Simulating Electron Effects in Heavy-Ion Accelerators with Solenoid Focusing electron, simulation, target, lattice 3603
 
  • W. M. Sharp
  • R. H. Cohen, A. Friedman, D. P. Grote, A. W. Molvik
    LLNL, Livermore, California
  • J. E. Coleman, P. K. Roy, P. A. Seidl, J.-L. Vay
    LBNL, Berkeley, California
  • I. Haber
    UMD, College Park, Maryland
  Funding: This work was performed under the auspices of US DOE by the University of California Lawrence Livermore and Lawrence Berkeley National Laboratories under contracts W-7405-Eng-48 and DE-AC03-76SF00098.

Contamination from electrons is a concern for solenoid-focused ion accelerators being developed for experiments in high-energy-density physics (HEDP). These electrons, produced directly by beam ions hitting lattice elements or indirectly by ionization of desorbed neutral gas, can potentially alter the beam dynamics, leading to a time-varying focal spot, increased emittance, halo, and possibly electron-ion instabilities. The electrostatic particle-in-cell code WARP is used to simulate electron-cloud studies on the solenoid-transport experiment (STX) at Lawrence Berkeley National Laboratory. We present self-consistent simulations of several STX configurations to show the evolution of the electron and ion-beam distributions first in idealized 2-D solenoid fields and then in the 3-D field values obtained from probes. Comparisons are made with experimental data, and several techniques to mitigate electron effects are demonstrated numerically.

 
 
THPAS054 QUINDI - A Code to Simulate Coherent Emission from Bending Systems radiation, electron, acceleration, lattice 3612
 
  • D. Schiller
  • S. Reiche, M. Ruelas
    UCLA, Los Angeles, California
  With this, we present a newly developed code, QUINDI, to address the numerical challenge of calculating the radiation spectra from electron bunches in bending magnet systems. This provides a better tool for designing diagnostic systems such as bunch length monitors in magnetic chicanes. The program calculates emission on a first principle basis, combining the dominant emission processes in a bending magnet system - edge and synchrotron radiation. The core algorithm is based on the Lienard-Wiechert potential and utilizes parallel computer architecture to cover complete electron beam distributions with a high resolution spatial grid. The program is aimed towards long frequency components to model the coherence level of the emitted radiation from the electron bunch.  
 
THPAS080 Initial Density Profile Measurements using a Laser-Induced Fluorescence Diagnostic in the Paul Trap Simulator Experiment ion, laser, ion-source, plasma 3666
 
  • M. Chung
  • R. C. Davidson, P. Efthimion, E. P. Gilson, R. M. Majeski
    PPPL, Princeton, New Jersey
  Funding: Research supported by the U. S. Department of Energy.

Installation of a laser-induced fluorescence (LIF) diagnostic system has been completed and initial measurement of the beam density profile has been performed on the Paul trap simulator experiment (PTSX). The PTSX device is a linear Paul trap that simulates the collective processes and nonlinear transverse dynamics of an intense charged particle beam propagating through a periodic focusing quadrupole magnetic configuration. Although there are several visible transition lines for the laser excitation of barium ions, the transition from the metastable state has been considered first mainly because an operating, stable, broadband, and high-power laser system is available for experiments in this region of the red spectrum. The LIF system is composed of a dye laser, fiber optic cables, a line generator, which uses a Powell lens, collection optics, and a CCD camera system. Single-pass mode operation of the PTSX device is employed for the initial tests of the LIF system to make optimum use of the metastable ions. By minimizing the background light level, it is expected that enough signal to noise ratio can be obtained to re-construct the radial density profile of the ion beam.

 
 
FROAC02 RF Amplifier Choice for the ISAC Superconducting Linac linac, controls, power-supply, monitoring 3798
 
  • I. V. Bylinskii
  • K. Fong, J. Lu, A. K. Mitra, C. Owen
    TRIUMF, Vancouver
  A superconducting linac is being commissioned at TRIUMF as an extension to the existing room temperature accelerator of exotic ions at ISAC. It will increase the isotope final energy from 1.5 to 6.5 MeV/u. Acceleration is accomplished in 40 bulk niobium quarter wave superconducting cavities operating at 106 and 141 MHz. Each cavity is energized from an independent RF amplifier with power rating up to 1 kW cw. Both vacuum tube and solid state amplifiers were considered as a viable option for the drivers. The paper compares many important parameters of these 2 amplifiers such as reliability, serviceability, capital and maintenance costs, as well as operating characteristics: gain linearity, phase noise, phase drift and others. Test results of prototypes of both types of amplifiers and 1 year operational experience of 20 tube amplifiers are discussed. Based on that the amplifier design requirements are formulated.  
slides icon Slides  
 
FRPMN002 Preliminary Studies for Top-up Operations at the Australian Synchrotron synchrotron, injection, electron, storage-ring 3856
 
  • M. J. Boland
  • D. J. Peake
    ASP, Clayton, Victoria
  • R. P. Rassool
    Melbourne
  The Australian Synchrotron is now a fully commissioned synchrotron light source providing beam for users. With the facility now fully operational, the next major advancement in machine operations will be top-up mode. The advantages of running top-up are well documented by other third generation light sources; in broad terms it leads to a better quality beam for users and better experimental results. An overview will be given of the top-up runs that have been conducted and the instrumentation that was used. It has been demonstrated that top-up operation is possible, however improvements in injection efficiency and beam stability during injection are required before this can become a routine mode of operation.  
 
FRPMN003 Measurements of Impedance and Beam Instabilities at the Australian Synchrotron impedance, single-bunch, synchrotron, storage-ring 3859
 
  • R. T. Dowd
  • M. J. Boland, G. LeBlanc, M. J. Spencer, Y. E. Tan
    ASP, Clayton, Victoria
  • J. M. Byrd, F. Sannibale
    LBNL, Berkeley, California
  In this paper we present the first measurements of machine impedance and observed beam instabilities at the Australian Synchrotron. Impedance measurements are made by studying the single bunch behaviour with beam current, using optical and X-ray diagnostic beamlines. An observed coupled-bunch instability, its cause and cure is also discussed.  
 
FRPMN016 Wake Field Computations for the PITZ Photoinjector simulation, electron, vacuum, gun 3931
 
  • E. Arevalo
  • W. Ackermann, R. Hampel, W. F.O. Muller, T. Weiland
    TEMF, Darmstadt
  Funding: This work is supported in part by the EU under contract number RIDS-011935 (EUROFEL).

The computation of wake fields excited by ultra short electron bunches in accelerator components with geometrical discontinuities is a challenging problem, as an accurate resolution for both the small bunch and the large model geometry are needed. Several computational codes (PBCI, ROCOCO, CST PARTICLE STUDIO etc.) have been developed to deal with this type of problems. Wake field simulations of the RF electron gun of the Photoinjector Test Facility at DESY Zeuthen (PITZ) are performed whith different specialized codes. Here we present a comparison of the wake potentials calculated numerically obtained from the different codes. Several structures of the photoinjector are considered.

 
 
FRPMN020 Beam Profile Measurements Based on Light Radiation of Atoms Excited by the Particle Beam synchrotron, proton, cyclotron, quadrupole 3955
 
  • J. Dietrich
  • C. Boehme
    UniDo/IBS, Dortmund
  • A. H. Botha, J. L. Conradie, P. F. Rohwer
    iThemba LABS, Somerset West
  • T. Weis
    DELTA, Dortmund
  Funding: Supported by BMBF and NRF, project-code SUA06/003

Diagnostics of intense particle beams requires development of new nondestructive beam monitoring methods. There are several kinds of diagnostic devices based on registration of products of accelerated beam particles interaction with atoms and molecules of residual gas in an accelerator vacuum chamber. Usually these devices used as beam profile monitors, which register electrons or/and ions produced in collisions of beam particles with residual gas. Some attempts were performed in application of light radiation of excited atoms. However, up to now this direction in the beam diagnostics was not developed properly. Nondestructive method of beam diagnostic system based on light radiation of atoms excited by the beam particles has the advantages - insensitivity to external magnetic and electric fields and, as a consequence, to the beam space charge fields. It allows to get higher spatial and time resolution. Measurements under different conditions at COSY-Juelich and in a cyclotron beamline at I'Themba LABS are presented and the pro and contra of the method is discussed

 
 
FRPMN023 New Beam Diagnostic Developments at the Photo-Injector Test Facility PITZ dipole, electron, booster, quadrupole 3967
 
  • S. Khodyachykh
  • D. Alesini, L. Ficcadenti
    INFN/LNF, Frascati (Roma)
  • G. Asova, J. W. Baehr, C. H. Boulware, H.-J. Grabosch, M. Hanel, S. A. Korepanov, M. Krasilnikov, S. Lederer, A. Oppelt, B. Petrosyan, S. Rimjaem, J. Roensch, T. A. Scholz, L. Staykov, F. Stephan
    DESY Zeuthen, Zeuthen
  • T. Garvey
    LAL, Orsay
  • L. H. Hakobyan
    YerPhI, Yerevan
  • D. J. Holder, B. D. Muratori
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • R. Richter
    BESSY GmbH, Berlin
  • R. Spesyvtsev
    KhNU, Kharkov
  Funding: This work has partly been supported by the European Community, contracts RII3-CT-2004-506008 and 011935, and by the "Impuls- und Vernetzungsfonds" of the Helmholtz Association, contract VH-FZ-005.

The Photo-Injector Test Facility at DESY in Zeuthen (PITZ) is an electron accelerator which was built to develop and optimize high brightness electron sources suitable for SASE FEL operation. Currently, in parallel to the operation of the existing setup, a large extension of the facility and its research program is ongoing. The beam line which has a present length of about 13 meters will be extended up to about 21 meters within the next two years. Many additional diagnostics components will be added to the present layout. Two high-energy dispersive arms, an RF deflecting cavity and a phase space tomography module will extend the existing diagnostic system of the photo injector and will contribute to the full characterization of new electron sources. We will report on the latest developments of the beam diagnostics at PITZ.

 
 
FRPMN027 Non-Intercepting Electron Beam Transverse Diagnostics with Optical Diffraction Radiation at the DESY FLASH Facility background, radiation, electron, target 3982
 
  • E. Chiadroni
  • M. Castellano
    INFN/LNF, Frascati (Roma)
  • A. Cianchi
    INFN-Roma II, Roma
  • K. Honkavaara
    Uni HH, Hamburg
  • G. Kube
    DESY, Hamburg
  • V. M. Merlo, F. Stella
    Universita di Roma II Tor Vergata, Roma
  Funding: Work supported by the European Comunity Infra-structure Activity under the FP6 Structuring the European Research Area program (CARE, contract number RII3-CT-2003-506395)

The characterization of the transverse phase space for high charge density and high energy electron beams is a fundamental requirement in many particle accelerator facilities, since knowledge of the characteristics of the accelerated beams is of great importance for the successful development of the next generation light sources and linear colliders. The development of suitable beam diagnostics, non-invasive and non-intercepting, is therefore necessary to measure the properties of such beams. Optical Diffraction Radiation (ODR) is considered the most promise candidate, as testified by the interest of many laboratories all around the world. An experiment based on the detection of ODR has been set up at DESY FLASH Facility to measure the electron beam transverse parameters. The radiation is emitted by a 700 MeV-energy electron beam passing through a slit of 0.5 mm or 1 mm aperture depending on the beam size. The slit is opened by chemical etching on a screen made of aluminum deposited on a silicon substrate. Radiation is then detected by a air-cooled high sensitivity CCD camera. The status of the experiment and preliminary results are reported.

 
 
FRPMN056 Beam Current and Energy Measurement of the PEFP 20 MeV Accelerator proton, rfq, linac, controls 4129
 
  • H.-J. Kwon
  • Y.-S. Cho, I.-S. Hong, J.-H. Jang, D. I. Kim, H. S. Kim, K. T. Seol
    KAERI, Daejon
  Funding: This work is supported by the 21C Frontier R&D program in the Ministry of Science and Technology of the Korean government.

The beam test of the Proton Engineering Frontier Project (PEFP) 20 MeV proton linear accelerator started again, after the upgrade of the RF control system, One of the important goals of the test is to increase the beam current to the design level. Tuned current transformers were installed along the DTL tanks to measure the beam current itself and possible beam loss along the accelerator. Because there were no empty drift tubes, the current transformers should be installed between DTL tanks. Therefore, the tuning plans were developed to obtain the desired beam properties with the limited number of beam diagnostic devices. Also two BPMs for the time of flight measurement and energy degrader were installed at the end of the 20 MeV accelerator to measure the beam energy. In this paper, the overall test results including beam current and energy measurement are presented.

 
 
FRPMN062 OTR Interferometry Diagnostic for the A0 Photoinjector electron, scattering, radiation, simulation 4144
 
  • G. M. Kazakevich
  • H. Edwards, R. P. Fliller, V. A. Lebedev, S. Nagaitsev, R. Thurman-Keup
    Fermilab, Batavia, Illinois
  Funding: Operated by Universities Research Association, Inc. for the U. S. Department of Energy under contract DE-AC02-76CH03000.

OTR interferometry (OTRI) is an attractive diagnostic for investigation of relativistic electron beam parameters. The diagnostic is currently under development at the A0 Photoinjector. This diagnostic is applicable for NML accelerator test facility that will be built at Fermilab. The experimental setups of the OTR interferometers for the Photoinjector prototype are described in the report. Results of simulations and measurements are presented and discussed.

 
 
FRPMN064 Applications of Cherenkov Radiation in Dispersive and Anisotropic Metamaterials to Beam Diagnostics radiation, resonance, plasma 4156
 
  • A. V. Tyukhtin
  • S. P. Antipov
    ANL, Argonne, Illinois
  • A. Kanareykin, P. Schoessow
    Euclid TechLabs, LLC, Solon, Ohio
  Funding: US Department of Energy

Cherenkov radiation (CR) is extensively used for detection of charged particles. The prompt nature of the radiation is one major advantage for diagnostics that measure temporal properties of the beam. However, low signal levels and small angles of radiation with respect to the particle trajectory present limitations on the use of traditional detector media. Using modern artificial metamaterials as Cherenkov radiators can provide essential advantages. As a rule metamaterials are characterized by strong dispersion and anisotropy that can be engineered to the requirements of the detector. We present theoretical and numerical analyses of CR in bulk anisotropic and dispersive media and in waveguides. The properties exhibited by these materials (large angles of radiation, two maxima in the angular distributions, etc.) allow the design of detectors with unusual characteristics, like a detector that registers almost all moving particles, and simultaneously only particles with velocity exceeding a predetermined threshold. We consider the case of a material that is approximately equivalent to an isotropic left-handed medium that also presents advantages as a Cherenkov medium.

 
 
FRPMN082 Diagnostic and Timing Supports for Top-Up Injection Operation for the TLS injection, controls, storage-ring, synchrotron 4252
 
  • J. Chen
  • P. C. Chiu, K. T. Hsu, S. Y. Hsu, K. H. Hu, C. H. Kuo, D. Lee, C.-J. Wang, C. Y. Wu
    NSRRC, Hsinchu
  Routine top-up operation of Taiwan Light Source (TLS) was started from October 2005 after high efficiency multi-bunch instabilities suppression system put into service. To support the top-up operation, various diagnostics and timing supports are needed. These include diagnostics for injection efficiency, filling pattern of the storage ring, tune, instability, loss pattern measurement. Timing control of the injection process are also needed. Design consideration and details of these efforts will be summary in this report. Further possible improvement will be also discussed.  
 
FRPMN084 Beam Trip Event Diagnostic System for the TLS controls, kicker, insertion, insertion-device 4264
 
  • K. H. Hu
  • J. Chen, K. T. Hsu, C. H. Kuo, C. Y. Wu
    NSRRC, Hsinchu
  The beam trip event diagnostic system includes several eight channels high-speed digitizer for data acquisition, PC base computer and optical fibre network applies to capture data. The PC are also to serve signal processing, beam trip event analysis and archive. This system can integrate beam trip, interlock signal of SRF, waveform of the injection kicker, quench and interlock signal of the superconducting insertion device, and instability of the stored beam. This diagnostic system can be routine monitor signal and record beam trip event. Design consideration and details of the implementation will be summarized in this report.  
 
FRPMN085 Application of the IEEE-1394 and the GigE Vision Digital Cameras for Diagnostics in Taiwan Light Source controls, synchrotron, emittance, radiation 4270
 
  • C. H. Kuo
  • J. Chen, K. T. Hsu, S. Y. Hsu, K. H. Hu, D. Lee, C.-J. Wang, C. Y. Wu
    NSRRC, Hsinchu
  Digital camera has been adopted for the booster, storage ring and transport-line diagnostic recently at the Taiwan Light Source. The system provides low image distortion and lossless image transmission over long distances. The system is integrated with commercial software in the control system. The fully remote control supports various operations and application that is useful. These applications include of screen monitor equip in the booster and storage ring, wider dynamic range sensor and highly flexibility control for the emittance measurement in the transport line, booster and linac. System configuration and present status will be summarized in this report.  
 
FRPMN086 Beam Position Monitoring System Upgrade for the TLS feedback, controls, electron, power-supply 4276
 
  • C. H. Kuo
  • J. Chen, P. C. Chiu, K. T. Hsu, K. H. Hu
    NSRRC, Hsinchu
  Taiwan light source (TLS) equips with 59 beam position monitors (BPM). Existing Bergos's type multiplexing BPM electronics are working well during last decade. To improve the functionality of the BPM system, new type of BPM electronics (Liberal Electron) will be replace some existing multiplexing BPM electronics. Seamless integration of two kinds of electronics is via reflective memory. The high precision closed orbits were measured by multiplexing BPM via multi-channel PMC form factor 16-bits ADC modules and gigabit Ethernet fast access channel of Libera Electron. Turn-by-turn beam position measurement is also supported by new BPM electronics. Tune measurement is also possible by spectra analysis of the turn-by-turn beam position data. The preliminary version of the orbit data was sampled every millisecond. Fast orbit data were shared by reflective memory network to support fast orbit feedback application. Averaged data were updated to control database at a rate of 10 Hz. The system structure, software environment and preliminary beam test of the BPM system are summarized in this report.  
 
FRPMN089 Facility Wide Real-Time Beam Loss Monitoring & Control using FPGA Technology beam-losses, controls, synchrotron, target 4282
 
  • M. R.W. North
  The ISIS facility based at Rutherford Appleton Laboratory, Chilton, Didcot, UK is currently the worlds brightest pulsed Neutron Spallation Source producing a beam to target power of 160kW. It is critical during machine operation to reduce activation of machine components by monitoring and controlling beam losses. Beam loss detection is provided using a total of 82 gas ionisation chambers distributed throughout the Injector, 800MeV Synchrotron, the Extracted Proton Beamline and the new Extracted Proton Beamline for TS2. This paper outlines the design of a new Beam Loss Display and Beam Trip Unit which uses a high speed FPGA design to provide real time monitoring, beam loss data logging and increased beam trip reaction time.  
 
FRPMN118 LCLS-S1 Optical Transition Radiation Monitor undulator, linac, radiation, target 4396
 
  • W. Berg
  • L. Erwin, S. E. Shoaf, B. X. Yang
    ANL, Argonne, Illinois
  Funding: Work supported by the U. S. Department of Energy, under Contract Nos. DE-AC02-06CH11357 and DE-AC03-76SF00515.

ANL has developed a high-resolution optical transition radiation (OTR) imaging monitor system for the LCLS injection linac at SLAC. The imaging station, OTR-S1, will be located at the S1 spectrometer with a beam energy of 135 MeV. The system will be used to acquire 2-D transverse beam distributions of the accelerated photocathode-gun-generated electron beam. We anticipate an average beam current of 0.2-1 nC and nominal beam spot size of σ-x 130 microns, σ-y 100 microns. The imaging system was designed for a field of view h/v: 10x7.5 mm. The spatial resolution of ~12 microns was verified over the central 5x4 mm region in the visible. A 12-bit digital camera acquires the image and a Mac-based digital frame capturing system was employed for the initial lab-based performance testing of the device. We are reporting on system development, image capture system, testing methodology, and test data analysis. Commissioning results will be reported as they become available.

 
 
FRPMN119 Vector Processing Enhancements for Real-Time Image Analysis background, controls, photon 4399
 
  • S. E. Shoaf
  Funding: Work supported by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

A real-time image analysis system was developed for beam imaging diagnostics. An Apple Power Mac G5 with an Active Silicon LFG frame grabber were used to capture video images that were processed and analyzed. Software routines were created to utilize vector processing hardware to reduce the time to process images as compared to conventional methods. These improvements allow for more advanced image processing diagnostics to be performed in real time.

 
 
FRPMS018 1-MeV Electrostatic Ion Energy Analyzer ion, space-charge, sextupole, quadrupole 3940
 
  • F. M. Bieniosek
  • M. Leitner
    LBNL, Berkeley, California
  Funding: Work performed under the auspices of the U. S. Department of Energy by the university of California, Lawrence Berkeley National Laboratory under Contract No. DE-AC03-76F00098.

We describe a high resolution (a few x 10-4) 90-degree cylindrical electrostatic energy analyzer for 1-MeV (singly ionized) heavy ions for experiments in the Heavy Ion Fusion Science Virtual National Laboratory. By adding a stripping cell, the energy reach of the analyzer is extended to 2 MeV. This analyzer has high dispersion in a first-order focus with bipolar deflection-plate voltages in the range of ±50 kV. We will present 2- and 3-D calculations of vacuum-field beam trajectories, space-charge effects, field errors, and a multipole corrector. The corrector consists of 12 rods arranged in a circle around the beam. Such a corrector has excellent properties as an electrostatic quadrupole, sextupole, or linear combination. The improved energy diagnostic allows measurements of beam charge state and energy spread, such as caused by charge exchange or temperature anisotropy, and better understanding of experimental results in longitudinal beam studies.

 
 
FRPMS020 Optical Beam Timing Monitor Experiments at the Advanced Light Source laser, storage-ring, instrumentation, pick-up 3952
 
  • S. De Santis
  • J. M. Byrd, R. B. Wilcox
    LBNL, Berkeley, California
  • Y. Yin
    Y. Y. Labs, Inc., Fremont, California
  Funding: Work supported by the U. S. Department of Energy under Contract No. DE-AC0-05CH11231.

We present the results of an experimental study of a beam timing monitor based on a technique demonstrated by Loehl*. This technique uses the electrical signal from a beam position monitor to amplitude-modulate a train of laser pulses, converting timing jitter into an amplitude jitter. This modulation is then measured with a photodetector and sampled by a fast ADC. This approach has already demonstrated sub-100 fsec resolution and promises even better results. Our study focuses on the use of this technique for precision timing for storage rings. We show results of measurements using signals from the Advanced Light Source.

* F. Loehl, et al., Proc. of the 2006 EPAC., p. 2781.

 
 
FRPMS033 OTR Measurements of the 10 keV Electron Beam at the University of Maryland Electron Ring (UMER) radiation, electron, target, polarization 4006
 
  • R. B. Fiorito
  • B. L. Beaudoin, S. J. Casey, D. W. Feldman, P. G. O'Shea, B. Quinn, A. G. Shkvarunets
    UMD, College Park, Maryland
  Funding: Research supported by Office of Naval Research, Joint Technology Office, and the Department of Energy

We present strong evidence of the observation of optical transition radiation (OTR) from aluminized silicon targets intercepting the UMER 10 keV, 100 ns pulsed electron beam, using fast (300ps and 1ns rise time) photomultiplier tubes. An intensified gated (3ns-1ms) CCD camera is used to image the beam using OTR and to study its time evolution throughout the beam pulse. A comparison of wave forms and time resolved OTR images is presented along with time integrated images obtained with phosphor screens for different initial conditions, i.e. beam currents and gun bias voltages.

correspondance email: rfiorito@umd.edu

 
 
FRPMS042 Electron Beam Diagnostics for Compact 1.2 GeV Booster Synchrotron booster, synchrotron, linac, storage-ring 4051
 
  • V. Popov
  • M. D. Busch, S. M. Hartman, J. Li, S. F. Mikhailov, P. W. Wallace, P. Wang, Y. K. Wu
    FEL/Duke University, Durham, North Carolina
  • G. Y. Kurkin
    BINP SB RAS, Novosibirsk
  Funding: Supported by US DoE grant #DE-FG02-01ER41175.

First operational experience has been gained with the linac and booster diagnostic system during the commissioning of the booster synchrotron at Duke University. Beam charge measurements are provided by Faraday cups, Integrated Current Transformers (ICT) and Modular Parametric Current Transformer (MPCT). Beam position monitoring is based on BPM system delivered from Bergoz company. Betatron tune measurements use synchrotron radiation (SR) and are different for two modes of operation: stored beam and energy ramping. Transverse profile and temporal beam structure monitoring employ insertable screens, CCD cameras, striplines and dissector. The diagnostics provided good understanding of electron beam behavior and allowed to adjust important beam parameters within design specifications. An overview of the diagnostic instrumentation of the Duke linac and booster synchrotron is given along with measurement examples and discussion of operational experience.

 
 
FRPMS048 Characterization of a High Current Induction Accelerator Electron Beam via Optical Transition Radiation from Dielectric Foils electron, radiation, simulation, induction 4087
 
  • V. Tang
  • C. G. Brown, T. L. Houck
    LLNL, Livermore, California
  Funding: This work was performed under the auspices of the U. S. Department of Energy by University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.

Traditionally, thin metal foils are employed for optical transition radiation (OTR) beam diagnostics but the possibility of plating or shorting accelerator insulating surfaces precludes their routine use on high-demand machines. The successful utilization of dielectric foils in place of metal ones would alleviate this issue but necessitates more modeling and understanding of the OTR data for inferring desired beam parameters because of the dielectric's finite permittivity. Additionally, the temperature dependence of the relevant foil parameters must be accounted for due to instantaneous beam heating. Here, we analyze quartz and kapton foil OTR data from the Flash X-Ray (FXR) induction linear accelerator using a model that includes these effects and discuss the resultant FXR beam profiles.

 
 
FRPMS050 LANSCE-Linac Beam-Centroid Jitter in Transverse Phase Space simulation, target, quadrupole, dipole 4093
 
  • B. Blind
  • J. D. Gilpatrick
    LANL, Los Alamos, New Mexico
  Funding: Work supported by the US Department of Energy under contract DE-AC52-06NA25396.

In order to characterize the beam-centroid jitter in transverse phase space, sets of position data of the 100-MeV H+ beam and 800-MeV H- beam were taken in the transport lines of the Los Alamos Neutron Science Center (LANSCE) accelerator complex. Subsequent data evaluation produced initially puzzling inconsistencies in the phase-space plots from different pairs of beam-position monitors. It is shown that very small random measurement errors will produce systematic differences between plots that should nominally be identical. The actual beam-centroid jitter and the amount of random error in the measurements can be extracted from the data by performing simulations and determining the parameters for which the resulting plots are consistent with the results from the data. Examples will be shown.

 
 
FRPMS053 Electromagnetic Modeling of Beam Position and Phase Monitors for LANSCE Linac linac, coupling, pick-up, simulation 4111
 
  • S. S. Kurennoy
  Electromagnetic modeling has been used to compare pickup designs of the beam position and phase monitors (BPPM) for the Los Alamos Neutron Science Center (LANSCE) linac. This study is a part of the efforts to upgrade LANSCE beam diagnostics*. MAFIA 3-D time-domain simulations with an ultra-relativistic beam allow computing the signal amplitudes and phases on the BPPM electrodes for the given processing frequency, 402.5 MHz, as functions of the beam transverse position. An analytical model can be applied to extrapolate the simulation results to lower beam velocities. Based on modeling results, a BPPM design with 4 one-end-shorted electrodes each covering 60-degree subtended angle, similar to the SNS linac BPPM**, appears to provide the best combination of mechanical and diagnostics properties for the LANSCE side-coupled linac.

* J. D. Gilpatrick et al. These proceedings.** S. S. Kurennoy and R. E. Shafer, EPAC 2000 (Vienna, Austria, 2000), 1768.

 
 
FRPMS054 PSR Electron Cloud Detector and Suppressor Mechanical Design and Fabrication electron, quadrupole, vacuum, beam-transport 4117
 
  • J. F. O'Hara
  • M. J. Borden, A. A. Browman, N. A. Gillespie, D. Martinez, K. G. McKeown, F. R. Olivas
    LANL, Los Alamos, New Mexico
  • J. E. Ledford, R. J. Macek
    TechSource, Santa Fe, New Mexico
  Funding: Work supported by DOE SBIR Grant No. DE-FG02-04ER84105 and CRADA No. LA05C10535 between TechSource, Inc. and the Los Alamos National Laboratory.

In order to better understand the two stream e-p instability issue in the LANSCE Proton Storage Ring, a new diagnostic instrument has been developed to measure the electron cloud formation and trapping in a quadrupole magnet at the LANSCE, PSR. The device called the Electron Cloud Detector (ECD) was fabricated and has successfully been installed in the PSR. Along with the Electron Cloud Detector, an additional device was developed to manipulate electrons ejected from the quadrupole and allow additional information to be obtained from ECD measurements. This paper will discuss the mechanical design and fabrication issues encountered during the course of developing both devices.

 
 
FRPMS065 Bunch Length Measurements in SPEAR3 optics, single-bunch, impedance, radiation 4159
 
  • W. J. Corbett
  • A. S. Fisher, X. Huang, J. A. Safranek, J. J. Sebek
    SLAC, Menlo Park, California
  • A. H. Lumpkin
    ANL, Argonne, Illinois
  • W. Y. Mok
    Life Imaging Technology, Palo Alto, California
  Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515 and Office of Basic Energy Sciences, Division of Chemical Sciences.

In the nominal SPEAR3 storage ring optics, the natural radiation pulse length is 40ps fwhm per bunch. Due to the double-bend achromat lattice configuration, it is relatively straightforward to reduce the momentum compaction factor (α) and hence reduce the bunch length by modest values. In this paper we present streak camera measurements of the bunch length in the nominal optics, and with ~α/20 and α/50 optics as a function of single-bunch current. The results demonstrate <10ps fwhm radiation pulses with up 5x108 particles/bunch (~100μ amp). Radiation pulse power, bunch length scaling and broadband impedance estimates are discussed.

 
 
FRPMS094 Beam Breakup Instabilities in Dielectric Structures simulation, single-bunch, injection, controls 4300
 
  • A. Kanareykin
  • W. Gai, J. G. Power
    ANL, Argonne, Illinois
  • C.-J. Jing, A. L. Kustov, P. Schoessow
    Euclid TechLabs, LLC, Solon, Ohio
  Funding: This research is supported by the US Department of Energy

We report on the experimental and numerical investigation of beam breakup (BBU) effects in dielectric structures resulting from parasitic wakefields. The experimental program focuses on measurements of BBU in a number of wakefield devices: (a) a 26 GHz power extraction structure; (b) a high gradient dielectric wakefield accelerator; (c) a wakefield structure driven by a high current ramped bunch train for multibunch BBU studies. New beam diagnostics will provide methods for studying parasitic wakefields that are currently unavailable at the AWA facility. The numerical part of this research is based on a particle-Green's function based beam breakup code we are developing that allows rapid, efficient simulation of beam breakup effects in advanced linear accelerators. The goal of this work is to be able to compare the accurate numerical results obtained from the new BBU code with the results of the detailed experimental measurements. An external focusing system for the control of the beam in the presence of strong transverse wakefields is considered.

 
 
FRPMS116 Diagnostics of BNL ERL beam-losses, gun, injection, emittance 4387
 
  • E. Pozdeyev
  • I. Ben-Zvi, P. Cameron, K. A. Drees, D. M. Gassner, D. Kayran, V. Litvinenko, G. J. Mahler, T. Rao
    BNL, Upton, Long Island, New York
  Funding: Work supported by U. S. DOE under contract No DE-AC02-98CH1-886

The ERL Prototype project is currently under development at the Brookhaven National Laboratory. The ERL is expected to demonstrate energy recovery of high-intensity beams with a current of up to a few hundred milliamps, while preserving the emittance of bunches with a charge of a few nanocoulombs produced by a high-current SRF gun. To successfully accomplish this task the machine will include beam diagnostics that will be used for accurate characterization of the three dimensional beam phase space at the injection and recirculation energies, transverse and longitudinal beam matching, orbit alignment, beam current measurement, and machine protection. This paper outlines requirements on the ERL diagnostics and describes its setup and modes of operation.