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Paper Title Other Keywords Page
MOPA008 On the Feasibility of a Tripler Upgrade for LHC dipole, synchrotron, injection, multipole 634
  • P.M. McIntyre, A. Sattarov
    Texas A&M University, College Station, Texas
  Funding: This work is supported by the U.S. Dept. of Energy, grant #DE-FG03-95ER40924.

Recent developments in the performance of superconductors and the design of high-field superconducting dipoles have opened the possibility to extend dipole field strength to ~25 Tesla in the arc dipoles of a future hadron collider. Design issues are presented for a concept of a Tripler upgrade of LHC, in which a second dual ring would be installed over the LHC ring in the same tunnel. Proton beams from LHC would be transferred to the Tripler midway through the LHC cycle and accelerated to ~20 TeV/beam for collisions. A number of obvious issues are explored. Synchrotron radiation power would be 80 times greater, but the critical energy would come as soft X-rays rather than hard UV, and so could be absorbed locally on ~150 K photon stops following each dipole so that total refrigeration power could perhaps be no more than that for LHC. Synchrotron damping would be dramatically enhanced in the Tripler compared to LHC, with damping times of ~one hour. Alternatives for beam transfer and low-beta insertions will be discussed. Like LHC, the Tripler would access new mass scales primarily through gluon fusion. The Tripler should reach about twice the mass scale attainable with LHC.

MPPE080 Transversal Deflection of Electrons Moving in Parallel with Linearly Polarized Laser Beam and its Application electron, laser, interaction-region, polarization 4054
  • D.A. Zakaryan, D.K. Kalantaryan
    YSU, Yerevan
  • E.D. Gazazyan, K.A. Ispirian, M.K. Ispirian
    YerPhI, Yerevan
  The motion of electrons in linearly polarized laser beams in a finite length interaction region and after in a field free drift length is investigated. It is shown that in the interaction region the trajectory of the electrons is almost straight lines with very small oscillation weakly depending on the laser intensity. In the drift region the electrons acquire significant transversal deflection that allows to carry out the measurement of the length and longitudinal particle distribution of femtosecond bunches. The dependence of this deflection upon the electron energy, interaction region length, etc is studied. The principles of the construction of femtosecond oscilloscopes are discussed.  
MPPP017 User Operation and Upgrades of the Fast Orbit Feedback at the SLS feedback, insertion, beam-losses, damping 1538
  • M. Böge, B. Keil, A. Lüdeke, T. Schilcher
    PSI, Villigen
  A report on the performance of the fast orbit feedback (FOFB) in its 2nd year of user operation is given. Photon beam position monitors (XBPM) have been included by means of a slow feedback which changes the reference settings of the FOFB. Users are permitted to change the XBPM references within certain limits while the feedback is running. A fast synchronous readout of the XBPMs allows their integration into the FOFB loop. The FOFB will be extended by an additional beam position monitor (BPM) in order to satisfy the requirements of the upcoming FEMTO project.  
MPPP018 Correction of Insertion Device Induced Orbit Distortions at the SLS feedback, undulator, insertion, insertion-device 1584
  • M. Böge, J.T.M. Chrin, G. Ingold, B. Keil, J. Krempasky, T. Schilcher, V. Schlott, T. Schmidt, A. Streun
    PSI, Villigen
  Corrections of insertion device (ID) induced orbit distortions at the SLS are performed by means of feed forward schemes down to the micron level at the corresponding photon beam position monitors (XBPMs). The remaining orbit fluctuations are suppressed by XBPM feedbacks which are an integral part of the fast orbit feedback system. As a result, sub-um RMS stability at the XBPMs is achieved while the ID settings are varied.  
MPPP019 Beam Orbit Diagnostics and Control in CANDLE Storage Ring electron, diagnostics, closed-orbit, storage-ring 1655
  • G.A. Amatuni, Y.L. Martirosyan, R.H. Mikaelyan, V.M. Tsakanov, A. Vardanyan
    CANDLE, Yerevan
  Stability requirements for the CANDLE light source are the consequence of a small electron beam size and a tolerable photon beam parameters. In a real machine, the components of the storage ring have static and dynamic imperfections, which cause disturbance of the electron beam and consequently photon beams parameters. In the present paper the basic approaches to the beam diagnostics, control and correction issues for the CANDLE facility are given. The algorithms, electronics and processing hardware are described.  
MPPT023 A New Magnetic Field Integral Measurement System acceleration, insertion, insertion-device, multipole 1808
  • J.Z. Xu, I. Vasserman
    ANL, Argonne, Illinois
  Funding: Work supported by U.S. Department of Energy Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

In order to characterize the insertion devices at the Advanced Photon Source (APS) more efficiently, a new stretched-coil magnetic field integral measurement system has been developed. The system uses the latest state-of-the-art field programmable gate array (FPGA) technology to compensate the speed variations of the coil motions. Initial results demonstrate that the system achieves the system measurement accuracy of 0.15 Gauss centimeter (G-cm) in a field integral measurement of 600 G-cm, probably the world’s best accuracy of its kind.

MPPT035 Magnetic Field Analysis of Superconducting Undulators with Variable Field Polarization undulator, polarization, wiggler 2410
  • S.H. Kim
    ANL, Argonne, Illinois
  Funding: Work supported by the U.S. Department of Energy under Contract No. W-31-109-ENG-38.

An undulator with double-helix coils on a cylindrical beam tube is the classical method of producing a helical magnetic field. This type of device, however, can produce only circularly polarized radiation and has limited horizontal aperture for beam injection. A planar superconducting undulator SCU) unit of helical field, which generates horizontal and vertical fields perpendicular to the beam direction, is inserted in between the magnetic poles of a vertical-field unit. This paper analyzes the magnetic fields and a scaling law of the SCU. The angle of the coil windings for the inserted unit is analyzed to maximize the horizontal field Bx. The range of the optimum rotation angle, for the range of gap/period ratio 0.1 - 0.6, is calculated to 30 - 40 degrees.

MPPT036 R&D of Short-Period NbTi and Nb3Sn Superconducting Undulators for the APS undulator, vacuum, electron, injection 2419
  • S.H. Kim, C. Doose, R. Kustom, E.R. Moog, I. Vasserman
    ANL, Argonne, Illinois
  Funding: Work supported by the U.S. Department of Energy under Contract No. W-31-109-ENG-38.

A superconducting undulator (SCU) with a period of 14.5 mm is under development at the Advanced Photon Source (APS). The undulator is designed to achieve a peak field on the beam axis of 0.8 T with an 8 mm pole gap and an average current density of 1 kA/mm2 in the NbTi coil. A 22-period half-section of a SCU has been fabricated. The SCU half-section was charged up to near the average critical current density jc of 1.4 kA/mm2, and the stability margin was measured by imposing external heat fluxes on the coil at 4.2 K in pool boiling LHe. The magnetic fields along the midplane of the SCU were measured using a Hall-probe field-mapping unit installed in a vertical dewar. The first test of a Nb3Sn short-section SCU reached an average current density of 1.45 kA/mm2, slightly higher than the jc for the NbTi SCU.

MPPT066 Pulsed Undulator for Polarized Positron Production undulator, positron, power-supply, alignment 3676
  • A.A. Mikhailichenko
    Cornell University, Department of Physics, Ithaca, New York
  We represent here elements of design and results of testing for helical undulator with ~2.5-mm period, manufactured in Cornell LEPP for polarized positron production at SLAC. At 2.3 kA undulator reaches K~0.2 and operated up 30 Hz.  
MPPT077 Radiation of Electron in the Field of Plane Light Wave electron, radiation, laser, scattering 3997
  • A.Y. Zelinsky, I.V. Drebot, Yu.N. Grigor'ev, O.D. Zvonarjova
    NSC/KIPT, Kharkov
  • R. Tatchyn
    SLAC, Menlo Park, California
  In the work the process of electron interaction with field of oncoming light wave (Compton scattering) has been considered with methods of classical electrodynamics. As results of Lorenz equation integration the trajectories of electron motion in the wave field were derived. On the base of obtained results the expressions for electron radiation spectrum were produced.In the work dependences of spectrum shape on electron and photon beams parameters are analyzed.  
MPPT079 Commissioning of an APPLE-II Undulator at Daresbury Laboratory for the SRS undulator, electron, insertion-device, insertion 4051
  • J.A. Clarke, F.E. Hannon, D.J. Scott, B.J.A. Shepherd, N.G. Wyles
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  A new variable polarisation undulator of the APPLE-II type has been designed and constructed at Daresbury Laboratory. Initial magnet testing of the 56mm period device was followed by an intensive period of shimming to improve the field quality. After this was successfully completed the undulator was installed into the SRS and tests made of the effect of the device upon the electron beam. This beam commissioning was completed in a very short space of time with the beamline being given full control of the gap and phase of the magnet within a few weeks of installation. This paper summarises the measurement of the magnet and the shimming techniques employed to improve the field quality. It also describes the effect of the device upon the stored 2 GeV electron beam and the measures taken to minimise these effects during user operations.  
MPPT080 Design, Fabrication and Characterization of a Large-Aperture Quadrupole Magnet for CESR-c quadrupole, luminosity, alignment, focusing 4063
  • M.A. Palmer, J.A. Crittenden, J. Kandaswamy, A. Temnykh
    Cornell University, Department of Physics, Ithaca, New York
  • T.I. O'Connell
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  Funding: National Science Foundation.

Installation of a radiative Bhabha luminosity monitor for CESR-c operation in 2004 required replacing a 40-mm aperture steel quadrupole magnet with one of aperture 75 mm, while maintaining field-quality tolerances at the level of a few parts in $104. We present the design methodology using 2D- and 3D-finite-element field calculations, compare the calculated 3D integrals to flip-coil measurements, and discuss related mechanical tolerances.

TPAE023 3D Metallic Lattices for Accelerator Applications lattice, plasma, simulation, vacuum 1838
  • M.A. Shapiro, J.R. Sirigiri, R.J. Temkin
    MIT/PSFC, Cambridge, Massachusetts
  • G. Shvets
    The University of Texas at Austin, Austin, Texas
  Funding: DOE-HEP

We present the results of research on 3D metallic lattices operating at microwave frequencies for application in (1) accelerator structures with higher order mode suppression, (2) Smith-Purcell radiation beam diagnostics, and (3) polaritonic materials for laser acceleration. Electromagnetic waves in a 3D simple cubic lattice formed by metal wires are calculated using HFSS. The bulk modes in the lattice are determined using single cell calculations with different phase advances in all three directions. The Brillouin diagram for the bulk modes is presented and indicates the absence of band gaps in simple lattices except the band below the cutoff. Lattices with thin wires as well as with thick wires have been analyzed. The Brillouin diagram also indicates the presence of low frequency 3D plasmon mode as well as the two degenerate photon modes analogous to those in a 2D lattice. Surface modes for a semi-infinite cubic lattice are modeled as a stack of cells with different phase advances in the two directions along the surface. The surface modes are found for both the thin and thick wire lattices in the band below the cutoff. They demonstrate that the lattice acts as a negative dielectric constant material.

TPAE049 The UCLA/SLAC Ultra-High Gradient Cerenkov Wakefield Accelerator Experiment electron, radiation, simulation, laser 3067
  • M.C. Thompson, H. Badakov, J.B. Rosenzweig, G. Travish
    UCLA, Los Angeles, California
  • M.J. Hogan, R. Ischebeck, R. Siemann, D.R. Walz
    SLAC, Menlo Park, California
  • P. Muggli
    USC, Los Angeles, California
  • A. Scott
    UCSB, Santa Barbara, California
  • R.B. Yoder
  Funding: Work Supported by U.S. Dept. of Energy grant DE-FG03-92ER40693.

An experiment is planned to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range. This new UCLA/SLAC collaboration will take advantage of the unique SLAC FFTB electron beam and its demonstrated ultra-short pulse lengths and high currents (e.g., sz = 20 μm at Q = 3 nC). The electron beam will be focused down and sent through varying lengths of fused silica capillary tubing with two different sizes: ID = 200 μm / OD = 325 μm and ID = 100 μm / OD = 325 μm. The pulse length of the electron beam will be varied in order to alter the accelerating gradient and probe the breakdown threshold of the dielectric structures. In addition to breakdown studies, we plan to collect and measure coherent Cerenkov radiation emitted from the capillary tube to gain information about the strength of the accelerating fields. Status and progress on the experiment are reported.

TPAE051 Designing Photonic Crystal Devices for Accelerators lattice, coupling, simulation, electron 3164
  • G.R. Werner
    CIPS, Boulder, Colorado
  • J.R. Cary
    Tech-X, Boulder, Colorado
  Funding: This work supported by U.S. Department of Energy grant DE-FG02-04ER41317.

Photonic crystals (periodic dielectric structures with a lattice constant on the order of the wavelength of light) can have a wide range of properties. For instance, photonic crystals can be designed to be completely reflective within a certain bandwidth, thereby becoming a replacement for metal in accelerator structures such as waveguides and cavities. To see whether photonic crystals might find application in accelerators, and to design potential accelerator structures, we will need reliable computer simulations to predict fields and frequencies and other properties of photonic crystal structures. We propose to build photonic crystal structures in the microwave regime and test the validity of computer simulation against experiment. We can then explore more complex issues such as coupling to photonic crystal structures, higher-order mode rejection, and tunable photonic crystals.

TPAT097 CLIC Drive Beam and LHC Based FEL-Nucleus Collider collider, electron, linac, ion 4320
  • O. Yavas
    Ankara University, Faculty of Engineering, Tandogan, Ankara
  • H.-H. Braun, R. Corsini
    CERN, Geneva
  • S. Sultansoy
    Gazi University, Faculty of Science and Arts, Ankara
  Funding: Ankara University, Ankara, TURKEY.

Main parameters of CLIC-LHC based FEL-Nucleus collider are determined. The matching of beam structures for maximum luminosity is studied. The advantages of the collider with respect to the traditional Nuclear Resonance Fluorescence (NRF) methods are presented considering (/Gamma-/Gamma(prime)) reactions. Determination of unknown decay width, spin and parity of excited levels is discussed for Pb nucleus.

TPAT099 Main Parameters of ILC-Tevatron Based Lepton-Hadron and Photon-Hadron Colliders electron, collider, luminosity, proton 4335
  • S. Sultansoy
    Gazi University, Faculty of Science and Arts, Ankara
  • O. Cakir, A.K. Ciftci
    Ankara University, Faculty of Sciences, Tandogan/Ankara
  • E. Recepoglu
    Turkish Atomic Energy Authority, Ankara
  • O. Yavas
    Ankara University, Faculty of Engineering, Tandogan, Ankara
  Funding: Ankara University.

The construction of the ILC tangential to Tevatron ring will give opportunity to investigate electron-proton, positron-proton, electron-antiproton, positron-antiproton interactions at 1 TeV center of mass energy. The analysis of the lepton-hadron collisions in these energy region is very important both for understanding of strong interaction dynamics and for adequate interpretation of future LHC and VLHC data. In addition, ILC-Tevatron collider will provide a possibility to realize photon-hadron collisions in the same energy region using Compton backscattered laser photon of ILC electron beam. Main parameters of these colliders are estimated and their physics search potential is briefly discussed.

TOAB002 First Results from the VUV FEL at DESY electron, radiation, emittance, undulator 127
  • B. Faatz
    DESY, Hamburg
  The VUV-FEL is an upgrade of the TTF1-FEL, which was taken in operation until end 2002. During this phase of the project it showed lasing in the wavelength range from 80-120 nm and it successfully provided beam for two pilot experiments. For over one year, the machine has been redesigned and upgraded, based on the experience gained during the first phase, to a user facility extending the wavelength range. Commissioning started in february 2004. In this contribution, the characterization of the VUV-FEL will be discussed, its electron beam parameters, photon beam properties and the status of the coming user experiments.  
TOAB007 Femtoslicing in Storage Rings electron, laser, radiation, undulator 590
  • S. Khan
    BESSY GmbH, Berlin
  Funding: Funded by the Bundesministerium für Bildung und Forschung and by the Land Berlin.

The generation of ultrashort synchrotron radiation pulses by laser-induced energy modulation of electrons and their subsequent transverse displacement, now dubbed "femtoslicing," was demonstrated at the Advanced Light Source in Berkeley. More recently, a femtoslicing user facility was commissioned at the BESSY storage ring in Berlin, and another project is in progress at the Swiss Light Source. The paper reviews the principle of femtoslicing, its merits and shortcomings, as well as the variations of its technical implementation. Various diagnostics techniques to detect successful laser-electron interaction are discussed and experimental results are presented.

TOAB010 Research and Development of Variable Polarization Superconducting Undulator at the NSLS undulator, polarization, radiation, synchrotron 734
  • S. Chouhan, D.A. Harder, G. Rakowsky, J. Skaritka, T. Tanabe
    BNL, Upton, Long Island, New York
  Funding: Office Of Science.

In this work a new concept for the construction of planar variable polarization superconductive insertion device is presented. The construction of the device with 8 mm gap and magnetic period of 26 mm is described compared with permanent magnet insertion device with the same gap & period length, as well as with previously published concepts. Advantage of this design include: (1) electrical tunability for both right and left circular and elliptical, as well as linear vertical or horizontal, (2) it requires no compensation of unwanted vertical field component and (3) used only simple windings of superconductive wire in an interlaced pattern. As a first step towards the construction of full-length device we propose to build & test a short prototype that will serve as a proof of the concept for versatile variable polarization superconductor magnet.

TOAD001 Techniques for Pump-Probe Synchronisation of Fsec Radiation Pulses laser, electron, booster, undulator 59
  • H. Schlarb
    DESY, Hamburg
  The increasing interest on the production of ultra-short photon pulses in future generations of Free-Electron Lasers operating in the UV, VUV or X-ray regime demands new techniques to reliably measure and control the arrival time of the FEL-pulses at the experiment. For pump-probe experiments using external optical lasers the desired synchronisation is in the order of tens of femtoseconds, the typical duration of the FEL pulse. Since, the accelerators are large scale facilities of the length of several hundred meters or even kilometers, the problem of synchronisation has to be attacked twofold. First, the RF acceleration sections upstream of the magnetic bunch compressors need to be stabilised in amplitude and phase to high precision. Second, the remain electron beam timing jitter needs to be determined with femtosecond accuracy for off-line analysis. In this talk, several techniques using the electron or the FEL beam to monitor the arrival time are presented, and the proposed layout of the synchronisation system for the European XFEL towards the 10 fsec regime.  
TOPC001 Visualizing Electron Beam Dynamics and Instabilities with Synchrotron Radiation at the APS undulator, electron, storage-ring, diagnostics 74
  • B.X. Yang, A.H. Lumpkin
    ANL, Argonne, Illinois
  Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences under Contract No. W-31-109-ENG-38.

The Advanced Photon Source (APS) is a third generation hard x-ray source serving a large user community. In order to characterize the high-brilliance beams, the APS diagnostics beamlines have been developed into a full photon diagnostics suite. We will describe the design and capabilities of the APS visible light imaging line, the bend magnet x-ray pinhole camera, and a unique diagnostics undulator beamline. Their primary functions are to support the APS user operations by providing information on beam sizes (20 - 100 micrometers), divergence (3 – 25 microradians), and bunch length (20 – 50 ps). Through the use of examples, we will show how these complementary imaging tools are used to visualize the electron dynamics and investigate beam instabilities. Special emphasis will be put on the use of undulator radiation, which is uniquely suitable for time-resolved imaging of electron beam with high spatial resolution, and for measurements of longitudinal beam properties such as beam energy spread and momentum compaction.

TPPE047 Fabrication and Measurement of Low Work Function Cesiated Dispenser Photocathodes cathode, electron, laser, dipole 2953
  • N.A. Moody, D.W. Feldman, P.G. O'Shea
    IREAP, College Park, Maryland
  • K. Jensen
    NRL, Washington, DC
  Funding: We gratefully acknowledge our funding agencies, the Joint Technology Office and the Office of Naval Research for their support.

Photoinjector performance is a limiting factor in the continued development of high powered FELs and electron beam-based accelerators. Presently available photocathodes are plagued with limited efficiency and short lifetime in an RF-gun environment, due to contamination or evaporation of a photosensitive surface layer. An ideal photocathode should have high efficiency at long wavelengths, long lifetime in practical vacuum environments, and prompt emission. Cathodes with high efficiency typically have limited lifetime, and vice versa, and the needs of the photocathode are generally at odds with those of the drive laser. A potential solution is the low work function dispenser cathode, where lifetime issues are overcome by periodic in situ regeneration that restores the photosensitive surface layer, analogous to those used in the microwave power tube industry. This work reports on the fabrication techniques and performance of cesiated metal photocathodes and cesiated dispenser cathodes, with a focus on understanding and improving quantum efficiency and lifetime, and analyzing issues of emission uniformity. The efficiency versus coverage behavior of cesiated metals is discussed and closely matches that predicted by recent theory.*

*K. L. Jensen, et al., "Photoemission from Low Work Function Coated Metal Surfaces: A Comparison of Theory to Experiment" (this conference).

TPPE053 Design Issues for the ILC Positron Source target, positron, electron, undulator 3230
  • V. Bharadwaj, Y.K. Batygin, R. Pitthan, D.C. Schultz, J. Sheppard, H. Vincke, J.W. Wang
    SLAC, Menlo Park, California
  • J.G. Gronberg, W. Stein
    LLNL, Livermore, California
  Funding: Work supported by Department of Energy contract DE-AC02-76SF00515.

A positron source for the ILC can be designed using either a multi-GeV electron beam or a multi-MeV photon beam impinging on a metal target. The major issues are: the drive beam, choice of target material, the design of the target station, the capture section, the target vault, and beam transport to the damping ring. In this paper, positron source parameters for the various schemes are outlined and the advantages and disadvantages of each scheme are discussed.

TPPP009 Precise Energy Measurements in Experiments on VEPP-4M Collider polarization, electron, energy-calibration, resonance 1138
  • A. Bogomyagkov, V.E. Blinov, V.P. Cherepanov, V. Kiselev, E. Levichev, S.I. Mishnev, N.Yu. Muchnoi, S.A. Nikitin, I.B. Nikolaev, D.M. Nikolenko, A.G. Shamov, E. Shubin, A.N. Skrinsky, Yu.A. Tikhonov, D.K. Toporkov, G.M. Tumaikin
    BINP SB RAS, Novosibirsk
  The series of experiments on mass measurements of J/Psi, Psi', X and D mesons have been done on VEPP4-M collider. The accuracy of obtained masses values for psi mesons exceeded world value more than 3 times. Experiment on mass measuremnt of tau lepton is in progress. All these experiments require absolute energy calibration of the beams. Resonant depolarization technique has been used for most accurate energy measurement with relative accuracy of 1 ppm (10-6). Compton backscattering effect is used in developing facility for fast energy measurements. Moller scattering of the beam on polarized gas jet target has been used for beam polarization measurements.  
TPPP010 Photon-Nucleon Collider Based on LHC and CLIC luminosity, electron, proton, collider 1207
  • H. Aksakal, A.K. Ciftci
    Ankara University, Faculty of Sciences, Tandogan/Ankara
  • D. Schulte, F. Zimmermann
    CERN, Geneva
  We describe the scheme of a photon-nucleon collider where high-energy photons generated by Compton back-scattering off a CLIC electron beam, at either 75 GeV or 1.5 TeV, are collided with protons or ions stored in the LHC. Different design constraints for such a collider are discussed and the achievable luminosity performance is estimated.  
TPPP042 Synchrotron Radiation in eRHIC Interaction Region radiation, synchrotron, synchrotron-radiation, interaction-region 2729
  • J. Beebe-Wang, C. Montag
    BNL, Upton, Long Island, New York
  • A. Deshpande
    Stony Brook University, Stony Brook
  • D.J. Rondeau
    Binghamton University, State University of New York, Binghamton, New York
  • B. Surrow
    MIT, Cambridge, Massachusetts
  Funding: Work performed under the auspices of the US DOE.

The eRHIC currently under study at BNL consists of an electron storage ring added to the existing RHIC complex. The interaction region of this facility has to provide the required low-beta focusing while accommodating the synchrotron radiation generated by beam separation close to the interaction point. In the current design, the synchrotron radiation caused by 10GeV electrons bent by low-beta triplet magnets will be guided through the interaction region and dumped 5m downstream. However, it is unavoidable to stop a fraction of the photons at the septum where the electron and ion vacuum system are separated. In order to protect the septum and minimize the backward scattering of the synchrotron radiation, an absorber and collimation system will be employed. In this paper, we first present the overview of the current design of the eRHIC interaction region with special emphasis on the synchrotron radiation. Then the initial design of the absorber and collimation system, including their geometrical and physical properties, will be described. Finally, our initial investigation of synchrotron radiation in the eRHIC interaction region, especially a simulation of the backward scattering from the absorber, will be presented.

TPPT013 Effect of HOM Couplers on the Accelerating Mode in the Damped Cavity at the Photon Factory Storage Ring coupling, electromagnetic-fields, storage-ring, factory 1339
  • T. Takahashi, M. Izawa, S. Sakanaka, K. Umemori
    KEK, Ibaraki
  • T. Koseki
    RIKEN/RARF/CC, Saitama
  Four damped cavities have been working very stably in the Photon Factory storage ring since 1997. The damped cavity has several trapped higher order modes (HOMs) with high Q values. Each frequency of these HOMs is detuned so as not to induce coupled-bunch instabilities. However, the frequency detuning method becomes less effective for a ring with a lower revolution frequency. Therefore, we have developed a HOM coupler that can reduce Q values of these trapped HOMs. The HOM coupler is a rod antenna type and located in the cylindrical wall of the cavity. Two or Three HOM couplers will be used for the cavity. The affect of these HOM couplers on the accelerating mode is investigated using MAFIA and the result is presented in this paper.  
TPPT035 High-Power RF Testing of a 352-MHz Fast-Ferrite RF Cavity Tuner at the Advanced Photon Source resonance, coupling, klystron, RF-structure 2407
  • D. Horan, E.E. Cherbak
    ANL, Argonne, Illinois
  Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences, under contract No. W-31-109-ENG-38.

A 352-MHz fast-ferrite rf cavity tuner, manufactured by Advanced Ferrite Technology, was high-power tested on a single-cell copper rf cavity at the Advanced Photon Source. These tests measured the fast-ferrite tuner performance in terms of power handling capability, tuning bandwidth, tuning speed, stability, and rf losses. The test system comprises a single-cell copper rf cavity fitted with two identical coupling loops, one for input rf power and the other for coupling the fast-ferrite tuner to the cavity fields. The fast-ferrite tuner rf circuit consists of a cavity coupling loop, a 6-1/8” EIA coaxial line system with directional couplers, and an adjustable 360° mechanical phase shifter in series with the fast-ferrite tuner. A bipolar DC bias supply, controlled by a low-level rf cavity tuning loop consisting of an rf phase detector and a PID amplifier, is used to provide a variable bias current to the tuner ferrite material to maintain the test cavity at resonance. Losses in the fast-ferrite tuner are calculated from cooling water calorimetry. Test data will be presented.

TPPT036 Higher-Order-Mode Damper Testing and Installation in the Advanced Photon Source 352-MHz Single-Cell RF Cavities storage-ring, simulation, vacuum, insertion 2443
  • G.J. Waldschmidt, N.P. Di Monte, D. Horan, L.H. Morrison, G. Pile
    ANL, Argonne, Illinois
  Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

Higher-order-mode dampers were recently installed in the storage ring rf cavities at the Advanced Photon Source to eliminate longitudinal coupled-bunch instability. It was discovered that the 540-MHz cavity dipole mode created beam instability at beam currents in excess of 85 mA causing horizontal emittance blowup. Methods of compensating for the instability by detuning the cavities and adjusting the cavity water temperature were becoming more difficult at higher beam currents as tests were performed to prepare for eventual 300-mA beam current operation. Electric field passive dampers located on the median plane of each cavity were determined to be the most promising solution. Simulation models were created and verified with low-power testing of the dampers. High-power testing of the dampers as well as conditioning of the damper ceramic load were also performed at the APS 352-MHz rf test stand and compared with simulation results. Preliminary test results will be discussed.

TPPT066 Successful Operation of the 500 MHz SRF Module at TLS synchrotron, electron, klystron, injection 3706
  • C. Wang, L.-H. Chang, S.-S. Chang, C.-T. Chen, F.-T. Chung, F.-Z. Hsiao, G.-Y. Hsiung, K.-T. Hsu, C.-C. Kuo, H.C. Li, M.-C. Lin, R.J. Lin, Y.K. Lin, G.-H. Luo, M.H. Tsai, J.Y. Yang, T.-T. Yang, M.-S. Yeh
    NSRRC, Hsinchu
  A superconducting radio frequency (SRF) cavity of CESR-III design was installed sucessfully in the electron storage ring at the National Synchrotron Radiation Research Center (NSRRC) in Taiwan. The project goals are to double the photon flux by raising the electron beam current and to increase the beam stability by taking advantage of the well-damped high-order modes of SRF cavity. Nowadays, SRF cavity has become the key technology for new synchrotron light sources under construction or planning worldwide. The first operational experience of the SRF cavity at the NSRRC will be presented.  
TOPA011 Self Consistent Scheme for Obtaining Electron-Positron Collisions with Multi-TeV Energy laser, acceleration, radiation, damping 740
  • A.A. Mikhailichenko
    Cornell University, Department of Physics, Ithaca, New York
  We describe here a self-consistent scheme for arrangement of multi-TeV collisions of electrons and positrons by using laser burst swept along microstructures with stable rate of acceleration ~10GeV/m. Shown that all component of the scheme are within present day technology. For energy ~1TeV luminosity could reach 1035 /cm2/s with wall-plug power of few tens of kW only.  
WOAA004 The ILC Beam Delivery System–Conceptual Design and R&D Plans extraction, optics, diagnostics, instrumentation 390
  • A. Seryi
    SLAC, Menlo Park, California
  The Beam Delivery System of the ILC has many stringent and sometimes conflicting requirements. To produce luminosity, the beams must be focused to nanometer size. To provide acceptable detector backgrounds, particles far from the beam core must be collimated. Unique beam diagnostics and instrumentation are required to monitor parameters of the colliding beams such as the energy spectrum and polarization. The detector and beamline components must be protected against errant beams. After collision, the beams must also be transported to the beam dumps safely and with acceptable losses. An international team is actively working on the design of the ILC Beam Delivery System in close collaboration. Details of the design, recent progress and remaining challenges will be summarized in this talk.  
WPAE007 Commissioning of the LNLS 2 T Hybrid Wiggler wiggler, storage-ring, vacuum, injection 1072
  • R.H.A. Farias, J.F. Citadini, M.J. Ferreira, J.G.R.S. Franco, A.F.A. Gouveia, L.C. Jahnel, L. Liu, R.T. Neuenschwander, X.R. Resende, P.F. Tavares, G. Tosin
    LNLS, Campinas
  • N.P. Abreu
    UNICAMP, Campinas, São Paulo
  Funding: MCT-CNPq, FAPESP.

We present the results of the commissioning of a 28-pole 2 T Hybrid Wiggler at the 1.37 GeV electron storage ring of the Brazilian Synchrotron Light Source. The wiggler will be used mainly for protein crystallography and was optimized for the production of 12 keV photons. The very high field and relatively large gap (22 mm) of this insertion device led to a magnetic design that includes large main and side magnets and heavily saturated poles. We present the results of the commissioning with beam, with special attention to the correction of the large linear tune-shift perturbations produced by the wiggler as well as on the reduction of beam lifetime at full energy. Since the injection at the LNLS storage ring is performed at 500 MeV we also focus on the effects of non-linearities and their impact on injection efficiency.

WPAE018 Performance Tests of Survey Instruments Used in Radiation Fields Around High-Energy Accelerators radiation, simulation, shielding, target 1595
  • S. Mayer, D. Forkel-Wirth, M. Fuerstner, H.G. Menzel, S. Roesler, C. Theis, H. Vincke
    CERN, Geneva
  Measurements of ambient dose equivalent in stray radiation fields behind the shielding of high-energy accelerators are a challenging task. Several radiation components (photons, neutrons, charged particles), spanning a wide range of energies, contribute to the total dose equivalent. In routine-measurements, the total dose equivalent is obtained by the combination of several radiation detectors. Ionisation chambers, which are sensitive to all radiation components, are employed together with so-called REM counters, which are responding mainly to neutrons. The total dose equivalent is correctly assessed provided that the response is interpreted carefully by using appropriate corrections and calibration factors. For this reason measurements were carried out in a high-energy reference field at CERN, which allows one to study the response of the different detectors in a mixed radiation field under controlled conditions. In addition, the field was simulated by Monte Carlo simulations. The outcome of these studies serves on one hand as a basis for quality assurance and improves on the other hand the knowledge of the instrument’s response for future applications at the LHC.  
WPAE030 Thermal Analysis of the Al Window for a New CESR-c Luminosity Monitor luminosity, positron, vacuum, simulation 2137
  • Y. He, D.H. Rice
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • Y. Li, M.A. Palmer
    Cornell University, Department of Physics, Ithaca, New York
  Funding: Work supported by the U.S. National Science Foundation.

A luminosity monitor using photons from radiative bhabha events at the CLEO interaction point (IP) has been installed in the Cornell Electron Storage Ring (CESR). A key vacuum and detector component is the photon window/converter whose uniformity and thickness are critical for determining the resolution of the total energy deposited in the segmented luminosity monitor. The window design must accommodate the operational requirements of the new monitor at CLEO-c beam energies of 1.5-2.5 GeV and also provide sufficient safety margin for operation at 5.3 GeV beam energies for Cornell High Energy Synchrotron Source (CHESS) running. During 5.3 GeV operation, intense stripes of synchrotron radiation from the interaction region superconducting quadrupole magnets as well as nearby bending magnets strike the window. During the course of window development, several materials and designs were evaluated. Thermal stresses were calculated using the finite element code ANSYS for various beam conditions to guide the cooling design. A window using aluminum alloy (6061-T6) was ultimately chosen to provide optimal performance for both CLEO-c and CHESS running conditions. The window has been in successful operation since September 2004.

WPAE050 First Calibrations of Alanine and Radio-Photo-Luminescence Dosemeters to a Hadronic Radiation Environment proton, radiation, simulation, hadron 3097
  • M. Fuerstner, I. Brunner, D. Forkel-Wirth, S. Mayer, H.G. Menzel, H. Vincke
    CERN, Geneva
  • I. Floret
    Ecole d'ingénieurs de Genève, Genève
  Alanine and Radio-Photo-Luminescence (RPL) dosimeters are used to monitor radiation doses occurring inside the tunnels of all CERN accelerators including the Large Hadron Collider (LHC). They are placed close to radiation sensitive machine components like cables or insulation of magnet coils to predict their remaining lifetime. The dosimeters are exposed to mixed high-energy radiation fields. However, up to now both dosimeter types are calibrated to 60Co-photons only. In order to study the response of RPL and alanine dosimeters to mixed particle fields like those occurring at CERN’s accelerators, an irradiation campaign at the CERN-EC High-Energy Reference field Facility (CERF-field) was performed. Moreover, the dosimeters were first time calibrated to a proton radiation field of a constant momentum of 24 GeV/c. In addition to the experiment FLUKA Monte Carlo simulations were carried out, which provide information concerning the energy deposition and the radiation field at the dosimeter locations.  
WPAE070 Injector Power Supplies Reliability Improvements at the Advanced Photon Source power-supply, septum, booster, beam-losses 3804
  • A.L. Hillman, S.J. Pasky, N. Sereno, R. Soliday, J. Wang
    ANL, Argonne, Illinois
  Funding: *Work supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

Operational goals for the APS facility include 97% availability and a mean time between unscheduled beam losses (faults) of 70 hours, with more than 5000 user hours of scheduled beam per year. To meet this objective, our focus has changed to maximizing the mean time between faults (MTBF). We have made various hardware and software improvements to better operate and monitor the injector power supply systems. These improvements have been challenging to design and implement in light of the facility operating requirements but are critical to maintaining maximum reliability and availability of beam for user operations. This paper presents actions taken as well as future plans to continue improving injector power supply hardware and software to meet APS user operation goals.

WPAP036 Determination of the Field Enhancement Factor on Photocathode Surface Via the Schottky Effect laser, cathode, electron, emittance 2425
  • Z.M. Yusof, M.E. Conde, W. Gai
    ANL, Argonne, Illinois
  Funding: U.S. Department of Energy.

Using photons with energy that is less than the work function, we employ the Schottky effect to determine the field enhancement factor on the surface of a Mg photocathode. The Schottky effect is manifested via a shift in the threshold for photoemission as the amplitude of the RF in the photoinjector gun is varied. From the threshold condition, we can directly determine the field enhancement factor on the cathode surface. This is a viable technique to obtain the field enhancement factor of surfaces of other materials such as Nb and Cu.

WPAP039 Progress on Lead Photocathodes for Superconducting Injectors cathode, vacuum, laser, gun 2598
  • J. Smedley, T. Rao
    BNL, Upton, Long Island, New York
  • P. Kneisel
    Jefferson Lab, Newport News, Virginia
  • J.L. Langner, P. Strzyzewski
    The Andrzej Soltan Institute for Nuclear Studies, Centre Swierk, Swierk/Otwock
  • R.S. Lefferts, A.R. Lipski
    SBUNSL, Stony Brook, New York
  • J.S. Sekutowicz
    DESY, Hamburg
  Funding: This work was supported by DOE contracts DE-AC02-98CH10886, DE-AC03-76SF00515 and DE-FG02-97ER82336.

We present the results of our investigation of bulk, electroplated and vacuum deposited lead as suitable photocathode materials for superconducting RF injectors. The quantum efficiency of each sample is presented as a function of the wavelength of the incident light, from 310 nm to 190 nm. Quantum efficiencies of 0.3% have been obtained. Production of a niobium cavity with a lead-plated cathode is underway.

WOAB008 CANDLE Project Overview brightness, storage-ring, ion, impedance 629
  • V.M. Tsakanov
    CANDLE, Yerevan
  CANDLE is a 3 GeV energy synchrotron light facility project in the Republic of Armenia. The main design features of the new facility are given. The results of the beam physics study in the future facility are overviewed including the machine impedance, ion trapping, single and multi-bunch instabilities, beam lifetime etc. The main requirements to the magnetic, RF and vacuum systems are discussed. The report includes the status of the project and the nearest R&D plans.  
RPAE005 The possibility for a Short-Period Hybrid Staggered Undulator undulator, brilliance, radiation, permanent-magnet 982
  • S. Sasaki
    ANL, Argonne, Illinois
  Funding: Work supported by the U.S. Dept. of Energy under Contract No. W-31-109-ENG-38.

Much work is underway to develop superconducting undulators in order to generate brilliant hard x-ray radiation at many synchrotron radiation facilities. However, in spite of many R&D efforts, it might take several years to reach this goal. On the other hand, the possibilities of cryogenic permanent magnet undulators are being investigated in order to provide an interim solution for hard x-ray users’ needs at Spring-8 and other facilities. However, although the in-vacuum undulator technology is well established, the in-vacuum gap-motion mechanism at a low temperature might cause major concerns regarding reliability and cost effectiveness. In this paper, the possibility for a cryogenic short-period staggered undulator was investigated. A simple model calculation by RADIA* shows that the effective undulator field is 0.825 T for a 15-mm-period staggered undulator at 6 mm gap with 1.36 T solenoid field. The pole material was assumed to be dysprosium, which has a saturation magnetization of 3.3 T at 77 K. The achievable maximum field of this simply structured device is close to that of a cryogenic permanent magnet undulator. We present calculated performances of cryogenic staggered undulators at various periods and gaps.

*O. Chubar, P. Elleaume, J. Chavanne, J. Synchrotron Radiat. 5, 481 (1998).

RPAE013 Laser System for Photoelectron and X-Ray Production in the PLEIADES Compton Light Source laser, scattering, electron, linac 1347
  • D.J. Gibson, C.P.J. Barty, S.M. Betts, K. Crane, I. Jovanovic
    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.

The PLEIADES (Picosecond Laser-Electron Interaction for the Dynamic Evaluation of Structures) facility provides tunable short x-ray pulses with energies of 30-140 keV and pulse durations of 0.3 – 5 ps by scattering an intense, ultrashort laser pulse off a 35-75 MeV electron beam. Synchronization of the laser and electron beam is obtained by using a photoinjector gun, and using the same laser system to generate the electrons and the scattering laser. The Ti:Sapphire, chirped pulse amplification based 500 mJ, 50 fs, 810 nm scattering laser and the similar 300 μJ, 5 ps, 266 nm photoinjector laser systems are detailed. Additionally, an optical parametric chirped pulse amplification (OPCPA) system is studied as a replacement for part of the scattering laser front end. Such a change would significantly simplify the set-up the laser system by removing the need for active switching optics, as well as increase the pre-pulse contrast ratio which will be important when part of the scattering laser is used as a pump beam in pump-probe diffraction experiments using the ultrashort tunable x-rays generated as the probe.

RPAE041 Reconstruction of Photon Factory Storage Ring for the Straight-Sections Upgrade Project quadrupole, emittance, undulator, factory 2678
  • T. Honda, S. Asaoka, W.X. Cheng, K. Haga, K. Harada, Y. Hori, M. Izawa, T. Kasuga, Y. Kobayashi, H. Maezawa, A. Mishina, T. Mitsuhashi, T. Miyajima, H. Miyauchi, S. Nagahashi, T. Nogami, T. Obina, C.O. Pak, S. Sakanaka, Y. Sato, T. Shioya, M. Tadano, T. Takahashi, Y. Tanimoto, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, S. Yamamoto
    KEK, Ibaraki
  The Photon Factory (PF) storage ring is a 2.5-GeV synchrotron light source at KEK. In 1997, we have accomplished a large reconstruction of the ring in order to reduce the beam emittance from 130 nm rad to 36 nm rad. After the reconstruction, the PF ring has continued a stable operation over 5000 hours a year. Now we are proceeding with another upgrade project to create four new straight sections and to largely lengthen the existing 10 straight sections. The shutdown for the upgrade project is scheduled for the period March-September 2005. The lattice configuration around the straight sections will be modified by replacing quadrupole magnets with new shorter ones and by placing them closer to the near-by bending magnets. Simultaneously the beam duct in two thirds of the storage ring will be replaced. Due to this modification of the lattice, the practical emittance will be reduced to 27 nm rad. The new straight sections will have low beta functions and suitable for housing short-period narrow-gap undulators. The in-vacuum undulators, which have a sufficiently high brilliance within a spectral range from 8 to 16 keV, are being developed now.  
RPAE042 Optimization of Kicker Pulse Bump by Using a SR Monitor at the Photon Factory injection, sextupole, kicker, factory 2717
  • T. Mitsuhashi, A. Ueda
    KEK, Ibaraki
  We plan to operate the Photon Factory storage ring by top-up injection mode from 2006. To realize this operation mode, remaining coherent oscillation of the stored beam due to error in the injection pulse bump is one of most serious problem. To reducing the error in the injection pulse bump, we calibrated kicking angles of the injection kicker magnets by means of the term by term instantaneous observation of beam profile. We have a SR monitor inside of injection pulse bump. By measureing the tern by tern beam position after the excitation of kicker magnet, we can calibrate the kick angle of the kicker magnet. By using this calibration, we optimized injection pulse bump. As a result, we reduced amplitude of remaining coherent oscillation less than 1/4 of the 1??of the beam size.  
RPAE043 Beam Position Monitor for Undulator by Using SR Monitor Technique undulator, radiation, focusing, monitoring 2789
  • T. Mitsuhashi, M.T. Tadano
    KEK, Ibaraki
  A beam position monitor for the undulator by using the optical SR monitor technique has been tested in the Photon Factory. A visible SR in far tail of the undurater spectrum is extracted by a water-cooled beryllium mirror. The extraction mirror has a hole in the center for passing through the central peak of the undulator radiation which has an opening angle of 1/gamma. Extracted visible light in large opening angle has exactly same optical axis of the undulator radiation, because of it’s a far tail of the spectrum of same radiation. We applied focusing system to observe the beam position in the undulator through the optical image of beam. The results show us this method is applicable to monitor a position of beam in the undulator, and gap change of undulator has no effect of beam position monitoring. We can easily measure the angle of visible ray, this method is applicable not only beam position monitor but also monitoring the angular deviation of undulator radiation.  
RPAE047 Lattice Study for the Taiwan Photon Source dynamic-aperture, emittance, sextupole, lattice 2989
  • C.-C. Kuo, H.-P. Chang, C.-T. Chen, G.-H. Luo, H.-J. Tsai, M.-H. Wang
    NSRRC, Hsinchu
  The feasibility study for the new 3.0~3.3 GeV Taiwan synchrotron light source, dubbed Taiwan Photon Source, was initiated in July, 2004. The goal is to construct a high performance light source with extremely bright X-ray in complementary to the existing 1.5 GeV light source in Taiwan. The ring circumference is 518.4 m and a 24-cell DBA lattice structure is chosen. The natural emittance with distributed dispersion is less than 2 nm-rad. A large booster ring of 499.2 m sharing the storage ring tunnel will be adopted.  
RPAE053 Transient Generation of Short Pulses in the APS Storage Ring synchrotron, simulation, storage-ring, single-bunch 3247
  • G. Decker, N. Sereno
    ANL, Argonne, Illinois
  Funding: This work is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

A method for obtaining very short pulses using modulation of the accelerating voltage gradient is described and simulation results given. The idea is to operate the two rf stations with a phase separation adjusted so that the synchronous particle resides on the crest of one of the sources. Phase modulation of the on-crest system at twice the synchrotron frequency induces a longitudinal bunch shape oscillation with significantly reduced bunch length occurring twice each synchrotron period. Pulsed and steady-state operation will be discussed using various accelerator parameters.

RPAE054 Beam Stability at the Advanced Photon Source insertion, insertion-device, vacuum, instrumentation 3268
  • G. Decker, O. Singh
    ANL, Argonne, Illinois
  Funding: This work is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

The Advanced Photon Source has been in operation since 1996. Since that time, extensive incremental improvements to orbit stabilization systems have been made. This includes the addition of 80 channels of narrowband rf beam position monitors (bpm's), 40 channels of bending magnet photon bpm's, and most recently the inclusion of 36 insertion device photon bpm's into the orbit correction response matrix. In addition, considerable improvements have been made in the area of power supply regulation, both for the main multipole magnets and the steering corrector magnets. The present status of overall performance will be discussed, including long term pointing stability, reproducibility, and AC beam motion.

RPAE056 NSLS II: The Future of the NSLS synchrotron, brightness, insertion, insertion-device 3345
  • J.B. Murphy, J. Bengtsson, R. Biscardi, A. Blednykh, G.L. Carr, W.R. Casey, S. Chouhan, S.B. Dierker, E. Haas, R. Heese, S. Hulbert, E.D. Johnson, C.C. Kao, S.L. Kramer, S. Krinsky, I.P. Pinayev, S. Pjerov, B. Podobedov, G. Rakowsky, J. Rose, T.V. Shaftan, B. Sheehy, J. Skaritka, N.A. Towne, J.-M. Wang, X.J. Wang, L.-H. Yu
    BNL, Upton, Long Island, New York
  Funding: Under Contract with the United States Department of Energy Contract Number DE-AC02-98CH10886

The National Synchrotron Light Source at BNL was the first dedicated light source facility and it has now operated for more than 20 years. During this time the user community has grown to more than 2400 users annually. To insure that this vibrant user community has access to the highest quality photon beams, the NSLS is pursuing the design of a new ultra-high brightness (~10E21) electron storage ring, tailored to the 0.3-20 KeV photon energy range. We present our preliminary design and review the critical accelerator physics design issues.

RPAE065 Generation of Picosecond X-Ray Pulses in the ALS Using RF Orbit Deflection electron, radiation, storage-ring, synchrotron 3659
  • D. Robin, J.M. Byrd, P. Fischer, P.A. Heimann, D.H. Kim, S. Kwiatkowski, D. Li, F. Sannibale, C. Steier, W. Wan, W. Wittmer, A. Zholents
    LBNL, Berkeley, California
  Funding: This work was supported by the Director, Office of Energy Research, Office of Basic Energy Sciences, Materials Sciences Division of the U.S. Department of Energy, under Contract No. DE-AC03-76SF00098.

A scheme is studied for producing ps length pulses of x-ray radiation from the Advanced Light Source (ALS) using two RF deflecting cavities. The cavities create vertical displacements of electrons correlated with their longitudinal position in the bunch. The two cavities separated by 180 degrees of vertical phase advance. This allows the vertical kick from one cavity to be compensated by the vertical kick of the other. The location of the cavities corresponds to the end of one straight section and the beginning of the following straight section. Halfway between the cavities a bending magnet source is located. The radiation from the bend can be compressed to ~1 ps in duration.

RPAE072 Simulations of X-Ray Slicing and Compression Using Crab Cavities in the Advanced Photon Source sextupole, emittance, radiation, synchrotron 3886
  • M. Borland, V. Sajaev
    ANL, Argonne, Illinois
  Funding: Work supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

Recently, Zholents et al. proposed applying to the Advanced Photon Source an x-ray compression scheme based on a pair of crab cavities and asymmetric cut crystals. We have explored the feasibility and potential performance of this scheme through simulation. We used the code elegant to perform 6-D tracking, allowing us to characterize the emittance growth, which is mostly a result of sextupoles between the cavities. We also explored tolerances on alignment, phase, and voltage of the cavities; lifetime effects; tradeoffs between cavity frequency and voltage; and performance with slicing alone instead of compression. Our conclusion is that sub-picosecond rms x-ray pulse lengths should be feasible.

RPAE073 Generating Picosecond X-Ray Pulses with Beam Manipulation in Synchrotron Light Sources synchrotron, coupling, simulation, electron 3898
  • W. Guo, M. Borland, K.C. Harkay, V. Sajaev, B.X. Yang
    ANL, Argonne, Illinois
  Funding: Work supported by U. S. Department of Energy, Office of Basic Energy Sciences under Contract No. W-31-109-ENG-38.

The length of x-ray pulses generated by storage ring light sources is usually tens of picoseconds. For example, the value is 40 ps rms at the Advanced Photon Source (APS). Methods of x-ray pulse compression are of great interest at the APS. One possible method, per Zholents et al., is to tilt the electron bunch with deflecting rf cavities.* Alternately, we found that the electron bunch can develop a tilt after application of a vertical kick in the presence of nonzero chromaticity. After slicing, the x-ray pulse length is determined by the tilt angle and the vertical beam size. In principal, sub-picosecond pulses can be obtained at APS. To date we have observed 6 ps rms visible light pulses with a streak camera. Efforts are underway to attempt further compression of the x-ray pulse and to increase the brilliance. This method can be easily applied to any storage ring light sources to generate x-ray pulses up to two orders of magnitude shorter than the electron bunch length. In this paper, we will present the theory of bunch tilt, particularly the synchrobetatron coupling and decoherence beam dynamics, and the simulation and the experimental results will also be shown as verification.

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

RPAP006 X-Band Linac Beam-Line for Medical Compton Scattering X-Ray Source laser, electron, linac, scattering 994
  • K. Dobashi
    NIRS, Chiba-shi
  • M. Akemoto, H. Hayano, T. Higo, J.U. Urakawa
    KEK, Ibaraki
  • F. Ebina, A. Fukasawa, T. Kaneyasu, H. Ogino, F. Sakamoto, M. Uesaka, Y. Yamamoto
    UTNL, Ibaraki
  Compton scattering hard X-ray source for 10~80 keV are under construction using the X-band (11.424 GHz) electron linear accelerator and YAG laser at Nuclear Engineering Research laboratory, University of Tokyo. This work is a part of the national project on the development of advanced compact medical accelerators in Japan. National Institute for Radiological Science is the host institute and U. Tokyo and KEK are working for the X-ray source. Main advantage is to produce tunable monochromatic hard ( 10-80 keV) X-rays with the intensities of 108-10 photons/s (at several stages) and the table-top size. Second important aspect is to reduce noise radiation at the beam dump by adopting the deceleration of electrons after the Compton scattering. The X-ray yield by the electron beam and Q-switch Nd:YAG laser of 2.5 J/10 ns is 107 photons/RF-pulse (108 photons/sec in 10 pps). X-band beam line for the demonstration is under commissioning. We also design to adopt a technique of laser circulation to increase the X-ray yield up to 109 photons/pulse (1010 photons/s). The construction of the whole system starts. X-ray generation and medical application will be performed in this year.  
RPAP012 Dual Energy X-Ray CT by Compton Scattering Hard X-Ray Source scattering, electron, simulation, linac 1291
  • M. Uesaka, T. Kaneyasu
    UTNL, Ibaraki
  • K. Dobashi, M. Torikoshi
    NIRS, Chiba-shi
  We have developed a compact Compton scattering hard X-ray source at Nuclear Engineering Research Laboratory, University of Tokyo. The compact hard X-ray source can produce tunable monochromatic hard X-rays. The monochromatic hard X-rays are required in large field of medical and biological applications. We are planning to perform dual-energy X-ray CT, which enables us to measure atomic number Z distribution and electron density re distribution in a material. The hard X-ray source has an advantage to perform dual-energy X-ray CT. The X-ray energy can be changed quickly by introducing a fundamental frequency and a second harmonic frequency lasers. This quick energy change is indispensable to medical imaging and very difficult in a large SR light source and others. The information on the atomic number and electron density will be used for treatment plan in radiotherapy as well as for identification of materials in a nondestructive test. We examined applicability of the dual-energy X-ray CT for atomic number measurement for low to medium Z elements (Z=30) by considering the X-ray profile generated by Compton scattering. Details of the numerical simulations and plans of the dual-energy X-ray CT will be reported in the conference.  
RPAP018 Identification of Nano-Objects in Substances by Using of X-Ray Electron Radiation electron, radiation, diagnostics, polarization 1610
  • V.K. Grishin
    MSU, Moscow
  Funding: Russian Foundation for Basic Researches, grant 03-02-16587.

Using opportunity of X-ray emission, arising at process of fast charge interaction with media atomic electrons, for nano-object discovery and diagnostics in substances is discussed. This kind of of X-ray emission termed as polarization bremsstrahlung radiation (PB) depends very strongly on media structure. As result spectra of PB in a media containing nano-inhomogeneities (as fullerenes, nanotubes, composite structures as fullerites) reflex structural characteristics of last ones. Fullerenes in carbon soot as example of an amorphous substance with mentioned structure inhomogeneities are considered. It is shown that spectra of PB on fullerenes contain a series of oscillations which give the valuable information about single- ore multilayers fullerene structures. The main peak of emission is placed in energy area of PB photons less than 1-1.5 keV. Here PB obtains a coherent character due to which one PB intensity is very high because it becomes to proportional square of all fullerene electrons number. Due to PB intensity depends weakly enough on observation angle, that permits to pick up PB signal from traditional bremsstrahlung radiation, and to facilitate measurement conditions.

RPAP033 Investigation of X-Ray Harmonics of the Polarized Inverse Compton Scattering Experiment at UCLA electron, laser, scattering, permanent-magnet 2303
  • A. Doyuran, R.J. England, C. Joshi, J. Lim, J.B. Rosenzweig, S. Tochitsky, G. Travish, O. Williams
    UCLA, Los Angeles, California
  Funding: U.S. Dept. of Energy grant DE-FG03-92ER40693.

An Inverse Compton Scattering (ICS) experiment, which will investigate nonlinear properties of scattering utilizing a terawatt CO2 laser system with various polarizations, is ongoing at the UCLA Neptune Laboratory. When the normalized amplitude of the incident laser’s vector potential a0 is larger than unity the scattering occurs in the nonlinear region; therefore, higher harmonics are also produced. ICS can be used, e.g., for a polarized positron source by striking a thin target (such as tungsten) with the polarized X-rays. As such, it is critical to demonstrate the production of polarized scattered photons and to investigate the ICS process as it enters the nonlinear regime. We present the description of the experimental set up and equipment utilized, including diagnostics for electron and photon beam detection. We present the current status of the experiment.

RPAP035 Photonuclear and Radiation Effects Testing with a Refurbished 20 MeV Medical Electron Linac linac, radiation, electron, target 2363
  • T. Webb, L.C. DeVeaux, F. Harmon, J.E. Petrisko, R.J. Spaulding
    IAC, Pocatello
  • R. Assink
    Sandia National Laboratories, Albuquerque, New Mexico
  • W. Beezhold
    ISU, Pocatello, Idaho
  An S-band 20 MeV electron linear accelerator formerly used for medical applications has been recommissioned to provide a wide range of photonuclear activation studies as well as various radiation effects on biological and microelectronic systems. Four radiation effect applications involving the electron/photon beams are described. Photonuclear activation of a stable isotope of oxygen provides an active means of characterizing polymer degradation. Biological irradiations of microorganisms including bacteria were used to study total dose and dose rate effects on survivability and the adaptation of these organisms to repeated exposures. Microelectronic devices including bipolar junction transistors (BJTs) and diodes were irradiated to study photocurrent from these devices as a function of peak dose rate with comparisons to computer modeling results. In addition, the 20 MeV linac may easily be converted to a medium energy neutron source which has been used to study neutron damage effects on transistors.  
RPAT047 Preliminary Design of a Femtosecond Oscilloscope electron, laser, interaction-region, electromagnetic-fields 2944
  • E.D. Gazazyan, K.A. Ispirian, A.T. Margaryan
    YerPhI, Yerevan
  • D.K. Kalantaryan
    YSU, Yerevan
  • E.M. Laziev
    CANDLE, Yerevan
  The calculations on motion of electrons in a finite length electromagnetic field of linearly and circularly polarized laser beams have shown that one can use the transversal deflection of electrons on a screen at a certain distance after the interaction region for the measurement of the length and longitudinal particle distribution of femtosecond bunches. In this work the construction and preliminary parameters of various parts of a device that may be called femtosecond oscilloscope are considered. The influence of various factors, such as the energy spread and size of the electron bunches, are taken into account. For CO2 laser intensity 1016 W/cm2 and field free drift length 1m the deflection is 5.3 and 0.06 cm, while the few centimeters long interaction length between 2 mirrors requires assembling accuracy 6 mm and 1.3 micron for 20 MeV to 50 keV, respectively.  
RPAT048 An X-Ray BPM and Accompanying Electronics diagnostics, synchrotron, feedback, synchrotron-radiation 3019
  • S.R. Marques, O.R. Bagnato, Bombacini, F.O. Bombacini, M.J. Ferreira, H. J. Onisto
    LNLS, Campinas
  Recent experiments at the LNLS Ultra Violet and X-Ray beam lines are pushing on the Synchrotron Radiation beam position stability requirements. In the direction of having photon Beam Position Monitor integrated to the orbit closed loop control system, we developed a staggered blades XR BPM and a four channel current measurement electronics. The BPM mechanical design was based on the SR masks previously developed and currently in use at the beam lines front end. By this design reuse, in addition to using an already available and well-tested, low cost construction technique, we expect to have a simple replacement of the SR masks by the XR BPMs in most of the beam lines, shortening the downtimes and the number of line parts to be replaced. We describe the design and the resulting performance of the XR BPM and the accompanying electronics.  
RPAT059 The SRI Beam Size Monitor Developed at NSRRC synchrotron, radiation, diagnostics, synchrotron-radiation 3465
  • T.C. Tseng, J.-R. Chen, H.C. Ho, C.-K. Kuan, C.J. Lin, S.Y. Perng, D.-J. Wang, J. Wang
    NSRRC, Hsinchu
  A beam size monitor based on the synchrotron radiation interferometer (SRI) was installed in the NSRRC TLS. This monitor consists of a simple diagnostic beamline with a water-cooled beryllium mirror inside and a detecting optical system for both vertical and horizontal beam size measurement. The beam sizes measured are 48 micron and 160 micron respectively and are more close to the theoretical values than the synchrotron image monitor. Comparing with other monitors, at least 1 micron beam size variation is detectable. To minimize the thermal effect, the mirror is located far away from the source point and closed to the detecting optical system. The thermal distortion of the mirror is quite small measured by a portable long trace profiler (LTP) and agrees with the simulating analysis. The detailed monitor system design and testing results are presented in this paper.  
RPAT062 Design and Operation of a Radiative Bhabha Luminosity Monitor for CESR-c luminosity, vacuum, monitoring, positron 3564
  • M.A. Palmer, D. L. Rubin, J.C. Smith
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • M. Cravey, J. Napalitano
    RPI, Troy, New York
  • V. Crede
    Cornell University, Department of Physics, Ithaca, New York
  • K.L. Dooley
    Vassar, Poughkeepsie, New York
  • H. Vogel
    CMU, Pittsburgh, Pennsylvania
  Funding: Work supported by the National Science Foundation.

The CLEO-c experiment at the Cornell Electron Storage Ring (CESR) is presently embarking on a multi-year exploration of charm and QCD physics in the 3-5 GeV center-of-mass energy range. In order to facilitate rapid optimization of machine parameters over this energy range, a luminosity monitor based on the measurement of radiative-bhabha photons coming from the CLEO-c interaction point (IP) has been designed and installed in the CESR ring. Key design criteria of the device include: better than 1% statistical measurements of the luminosity with a 1 Hz update rate over the full range of CESR-c operating conditions; bunch-by-bunch measurement capability; a large horizontal aperture to enable measurements under conditions ranging from single-bunch head-on collisions to multi-bunch collisions with a horizontal crossing angle of up to 4~mrad; and, a segmented readout to provide direct information on beam characteristics at the IP. We review the design and performance of this device and discuss its application to machine tuning and performance studies.

RPAT067 Beam Angle Measurement Using Cherenkov Radiation electron, radiation, optics, scattering 3742
  • T. Watanabe, M. Babzien, K. Kusche, V. Yakimenko
    BNL, Upton, Long Island, New York
  A simple beam angle monitor utilizing observation of far-field Cherenkov radiation is being developed. The monitor is independent of beam energy as well as position and requires only modest camera sensitivity. Since the wavefront of Cherenkov radiation is not spherical but planar, the far-field image is supposed to be infinetesimally small in one-dimensional geometrical optics, which may result in high angular resolution. In a practical experiment, however, beam scattering in a radiator and diffraction from a finite size radiation source determine the resolution. Numerical analysis shows that the angular resolution with a 100-um thickness fused silica radiator is 0.8 mrad. The experimental results with 2-mm and 100-um thickness fused silica are shown. The possibility of non-destructive measurement is also discussed.  
RPAT077 Beam Test Proposal of an ODR Beam Size Monitor at the SLAC FFTB target, radiation, optics, monitoring 4015
  • Y. Fukui, D. Cline, F. Zhou
    UCLA, Los Angeles, California
  • A. Aryshev, V. Karataev, T. Muto, M. Tobiyama, J.U. Urakawa
    KEK, Ibaraki
  • P.R. Bolton, M.C. Ross
    SLAC, Menlo Park, California
  • R. Hamatsu
    TMU, Hatioji-shi,Tokyo
  • G.A. Naumenko, A. Potylitsyn, A. Sharafutdinov
    Tomsk Polytechnic University, Physical-Technical Department, Tomsk
  We design a single bunch transverse beam size monitor which will be tested to measure the 29 GeV electron/positron beam at the SLAC FFTB beam line.The beam size monitor uses a CCD camera to make images of the interference pattern of the optical diffraction radiation from conductive slit target which are placed close to the beam path. In this method, destruction of the accelerated electron/positron beam bunches due to the beam size monitoring is negligible, which is vital to the operation of the Linear Collider project. A dis-phased conductive slit target and a lens system allow us to recover the sensitivity of the transverse beam size with a small photon yield ratio at the valley to that at the peak due to the large gamma*λ, and with the near field effect due to the large λ*gamma**2. A solution for non-negligible divergence at the SLAC FFTB is also discussed.  
RPAT083 Beam Profile Measurements and Simulations of the PETRA Laser-Wire laser, electron, simulation, collider 4123
  • J. Carter, I.V. Agapov, G.A. Blair, G.E. Boorman, C.D. Driouichi, F. Poirier, M.T. Price
    Royal Holloway, University of London, Surrey
  • K. Balewski, H.-C. Lewin, S. Schreiber, K. Wittenburg
    DESY, Hamburg
  • S.T. Boogert, S. Malton
    UCL, London
  • N. Delerue, D.F. Howell
    OXFORDphysics, Oxford, Oxon
  • T.  Kamps
    BESSY GmbH, Berlin
  The laser-wire will be an essential diagnostic tool at the International Linear Collider and advanced light sources. It uses a finely focussed laser beam to measure the transverse profile of electron bunches by detecting the Compton-scattered photons (or electrons) downstream of where the laser beam intersects the electron beam. Such a system has been installed at the PETRA storage ring at DESY, which uses a piezo-driven mirror to scan the laser light across the electron beam. Latest experimental results are presented and compared to detailed simulations using Geant4.  
RPAT090 The Study of New Signal Processing Technique in Photon Beam Position Monitors synchrotron, synchrotron-radiation, radiation, monitoring 4239
  • S.F. Lin, H. Gao, P. Lu, B. Sun, J. Wang
    USTC/NSRL, Hefei, Anhui
  A log-ratio signal processing technique in photon beam position monitors (PBPM) was presented in this paper. The main performances (e.g. sensitivity, position offset and linearity range) of split PBPM and a pair of wires PBPM were analyzed , and the result of the measurement fit well with the theory. An inexpensive logarithmic amplifier chip which can measure photon currents from 0.1nA to 3.5mA was used in electronic circuits. The logarithmic ratio of the signal amplitudes from the PBPM provides a real-time analog signal that has wider linearity range and higher bandwidth than signal processing technique.

Supported by Natural Science Foundation of China (10275062) and CAS Knowledge Innovation Project (KY4206).

RPAT092 Conceptual Design of an Insertion Device for Non-Destructive Beam Diagnostics of a Low-Emittance Synchrotron Light Source electron, undulator, radiation, diagnostics 4275
  • M. Masaki
    JASRI/SPring-8, Hyogo
  An insertion device is proposed to measure small vertical angular divergence and energy spread (dE/E) of electron beam in a low-emittance synchrotron light source. In accelerators such as the SPring-8 storage ring operated on the small emittance-coupling ratio, vertical divergence of spectral photon flux produced by electron beam in a conventional undulator of several meters long will be dominated by natural divergence of the undulator radiation. Therefore, the divergence of spectral flux is not useful for vertical emittance diagnostics. The proposed insertion device consists of N short undulator sections as x-ray radiators cascaded through vertical deflective sections to make a half-period cosine-like electron trajectory. Two radiation parts of the upper and lower sides are formed due to up-and-down electron orbit by the deflective sections. X-rays emitted from the two radiation parts interfere at observation point far from the insertion device. It was numerically studied that the vertical angular divergence in the sub-micro radian range and the energy spread of the 1·10-3 order could be measured by visibility and envelope width of an observed interference pattern, respectively.  
RPPE010 Beam Transport Devices for the 10kW Free Electron Laser at Thomas Jefferson National Accelerator Facility laser, electron, vacuum, beam-transport 1210
  • L.A. Dillon-Townes, C.P. Behre, M.E. Bevins, G.H. Biallas, D. Douglas, C.W. Gould, J.G. Gubeli, D.H. Kashy, R. Lassiter, L. Munk, G. Neil, M.D. Shinn, S. Slachtouski, D. Waldman
    Jefferson Lab, Newport News, Virginia
  Funding: Department of Energy

The beam transport vacuum components for the 10 kW Free Electron Laser (FEL) at Thomas Jefferson National Accelerator Facility (TJNAF) were designed to address 10 MeV electron beam characteristics and maintain an accelerator transport vacuum of 10-9 torr. The components discussed include a novel zero length beam clipper, novel shielded bellows, one decade differential pumping stations with a 7.62 cm (3.0”) aperture, and a 50 kW beam dump. Incorporation of these accelerator transport components assist in establishing the environment needed for the electron beam to produce the optical light required to lase at 10 kW.

RPPE044 Vacuum Modifications for the Installation of a New CESR-c Fast Luminosity Monitor vacuum, dipole, luminosity, synchrotron 2836
  • Y. Li, Y. He, M.A. Palmer
    Cornell University, Department of Physics, Ithaca, New York
  Funding: Work supported by the National Science Foundation.

In order to improve luminosity tuning and maintenance for the CLEO-c high energy physics (HEP) program at the Cornell Electron Storage Ring (CESR), a luminosity monitor using photons from radiative Bhabha events has been installed in the CESR ring. Over 10 meters of CESR vacuum chambers near the interaction region were modified to accommodate this new device. The vacuum modifications were designed to meet two criteria. First, the new vacuum chambers had to provide sufficient horizontal and vertical aperture for photons originating from the IP over a wide range of colliding beam conditions. Secondly, the new vacuum chambers required adequate safety margins for operation at beam energies up to 5.3 GeV for Cornell High Energy Synchrotron Source running. In order to be certain that the vacuum modifications would not give rise to any localized pressure bumps, a detailed calculation of the expected vacuum pressure distribution due to synchrotron radiation flux was carried out. Careful design and planning enabled a successful installation and resumption of CESR operations in record time.

RPPE053 R&D Status of Vacuum Components for the Upgrade of KEKB electron, vacuum, positron, impedance 3256
  • Y. Suetsugu, H. Hisamatsu, K.-I. Kanazawa, N. Ohuchi, K. Shibata, M. Shirai
    KEK, Ibaraki
  An upgrade plan of the KEK B-factory (KEKB), Super KEKB, aiming a luminosity over 1·1035 /cm2 /s has been discussed in KEK. To achieve the high luminosity, the stored beam currents are 4.2 - 9.4 A and the bunch length is 3 mm. In designing the vacuum system of the Super KEKB, therefore, the main issues are how to manage the resultant highly intense synchrotron radiation (SR) power, and how to reduce the beam impedance. The R&Ds for basic vacuum components, such as a beam duct, a bellows chamber, a connection flange, a collimator, a high-capacity pump and so on, are now undergoing to deal with the problems. For examples, a copper beam duct with an antechamber was manufactured to reduce the power density of SR, and to suppress the electrons around the beam for the positron ring. The test chamber was installed in the positron ring of KEKB and tested with a beam. Bellows chambers with a newly developed RF-shield were also installed in the ring and the property was investigated. A special connection flange with little step or gap inside was developed and examined in a test bench. The designs of these components and the results of tests are presented and discussed.  
RPPP015 Reconstruction of IP Beam Parameters at the ILC from Beamstraahlung simulation, radiation, luminosity, electron 1446
  • G.R. White, G.R. White
    SLAC, Menlo Park, California
  Funding: This work is supported by the Commission of the European Communities under the 6th Framework Programme "Structuring the European Research Area", contract number RIDS-011899.

The luminosity performance of the ILC will be very sensitive to the parameters of the colliding bunches. Only some of these parameters can be measured using planned instrumentation. This analysis aims to access some of the colliding beam parameters not available by other means and to improve on the resolution of those that are. GUINEA-PIG is used to simulate the beam-beam interactions and produce beamstrahlung radiation (e+/e- pairs and photons). These are tracked to a simulation of the low-angle Beam Calorimeter and a photon detector and event shapes are produced. A Taylor map is produced to transform from the event shapes to the simulated beam parameters. This paper reports on the progress of this analysis, examining the usefulness of the proposed fitting technique.

RPPP039 Heat Deposition in Positron Sources for ILC target, positron, electron, shielding 2574
  • V. Bharadwaj, R. Pitthan, J. Sheppard, H. Vincke, J.W. Wang
    SLAC, Menlo Park, California
  Funding: Work supported by Department of Energy contract DE-AC02-76SF00515.

In an ILC positron source, multi-GeV electrons or multi-MeV photons impinge on a metal target. In either case, the incoming beam power is hundreds of kilowatts. Various computer programs - such as FLUKA or MARS – can calculate how the incoming beam showers in the target and can track the particle showers through the positron source system. The incoming energy ends up as heat in the various positron source elements. This paper presents results from such calculations and their impact on the design of a positron source for the ILC.

RPPP048 Beam Collimation and Machine-Detector Interface at the International Linear Collider collimation, radiation, synchrotron, synchrotron-radiation 2995
  • N.V. Mokhov, A.I. Drozhdin, M.A. Kostin
    Fermilab, Batavia, Illinois
  Funding: Work supported by the Universities Research Association, Inc., under contract DE-AC02-76CH03000 with the U.S. Department of Energy.

Synchrotron radiation, spray from the dumps and extraction lines, beam-gas and beam halo interactions with collimators and other components in the ILC beam delivery system create fluxes of muons and other secondaries which can exceed the tolerable levels at a detector by a few orders of magnitude. It is shown that with a multi-stage collimation system, magnetized iron spoilers which fill the tunnel and a set of masks in the detector, one can hopefully meet the design goals. Results of modeling with the STRUCT and MARS15 codes of beam loss and energy deposition effects are presented in this paper. We concentrate on collimation system and mask design and optimization, short- and long-term survivability of the critical components (spoilers, absorbers, magnets, separators, dumps), dynamic heat loads and radiation levels in magnets and other components, machine-related backgrounds and damage in collider detectors, and environmental aspects (prompt dose, ground-water and air activation).

RPPT001 The BESSY Soft X-Ray FEL User Facility electron, undulator, linac, simulation 746
  • D. Kraemer
    BESSY GmbH, Berlin
  Funding: Funded by Zukunftsfonds Berlin.

The user requests for an optimized 2nd generation FEL facility in the VUV to soft X-ray range demand for ultra short photon pulses (t = 20 fs) at a peak power of several GW. A high shot to shot reproducibility of the pulse shape and pulse power allowing for fs-synchronization for pump-probe experiments is feasible in a seeded FEL approach. Free selectable photon polarization and wavelength tuning is essential for any 2nd generation FEL source like the proposed BESSY-Soft X-ray FEL user facility. Freely selectable pulse repetition rates and freely selectable pulse patterns, including fast switching to different parallel operating FEL-Lines are necessary ingredients, feasible with a suitable injector in combination with a CW-superconducting linac. The status of the BESSY HGHG-FEL project will be reviewed.

RPPT034 High-Resolution Undulator Measurements using Angle-Integrated Sponteneous Radiation undulator, electron, radiation, simulation 2342
  • B.X. Yang
    ANL, Argonne, Illinois
  Funding: Work supported by U. S. Department of Energy, Office of Basic Energy Sciences under Contract No. W-31-109-ENG-38.

The Linac Coherent Light Source (LCLS) is a fourth-generation light. Its proper operation requires a stringently controlled undulator field. The tolerance for the field parameter K is less than 1.5 × 10-4 for all thirty-three undulator segments totaling 112 meters. Even with the high quality of the LCLS electron beam (x- and y-emittance ~ 44 pm, energy spread ~0.03%), the fluctuation of the electron energy (~0.05%) presents a serious challenge to measurement techniques based on electron or x-ray beams. We propose a differential measurement technique that makes use of the angle-integrated spontaneous radiation intensities from two undulator segments. When the x-ray beams emitted from the two undulator segments are separated but allowed to pass through the same monochromator, the two beam intensities will change almost identically with the change of electron beam energy. As a result, the intensity difference becomes a very sensitive and reliable measure of the difference of the two undulators’ K-parameters. Results of comprehensive numerical simulations show that differences in the range of delta-K/K ~ 10-5 can be resolved, well within the tolerance for the LCLS operation.

RPPT044 Design, Construction and Commissioning of a NEG Coated Wiggler Vacuum Chamber for the LNLS Storage Ring vacuum, wiggler, insertion, insertion-device 2807
  • M.J. Ferreira, R.O. Ferraz, H.G. Filho, M.B. Silva
    LNLS, Campinas
  Funding: MCT - CNPQ - FAPESP

We present the design of the vacuum chamber for the LNLS 2 T Hybrid Wiggler. The chamber is a 3 m long, 1.2 mm thick 316 SS tube, which was mechanically pressed into an elliptical shape from an originally round tube. In order to provide the necessary mechanical tolerances, the rather flexible tube is welded to lateral supports that run the complete length of the chamber. Special care has been given to the mechanical and magnetic characterization of the chamber and the inner surface of the chamber was NEG-coated at the ESRF. We present the installation procedure as well the vacuum conditioning charge evolution.

RPPT075 Generation of Femtosecond Electron and Photon Pulses radiation, electron, synchrotron, lattice 3946
  • C. Thongbai, V. Jinamoon, Mr. Kangrang, K. Kusoljariyakul, S. Rimjaem, J. Saisut, T. Vilaithong
    FNRF, Chiang Mai
  • M.W. Rhodes, P. Wichaisirimongkol
    IST, Chiang Mai
  • H. Wiedemann
    SLAC, Menlo Park, California
  Funding: We are grateful to the Thailand Research Fund, the National Research Council of Thailand, the Thai Royal Golden Jubilee Scholarship, the U.S. Department of Energy, and the Hansen Experimental Physics laboratory of Stanford University.

Femtosecond electron and photon pulses become a tool of interesting important to study dynamics at molecular or atomic levels. Such short pulses can be generated from a system consisting of an RF-gun with a thermionic cathode, an alpha magnet as a magnetic bunch compressor, and a linear accelerator. The femtosecond electron pulses can be used directly or used as sources to produce electromagnetic radiation of equally short pulses by choosing certain kind of radiation pruduction processes. At the Fast Neutron Research Facility (Thailand), we are especially interested in production of radiation in Far-infrared and X-ray regime. In the far-infrared wavelengths which are longer than the femtosecond pulse length, the radiation is emitted coherently producing intense radiation. In the X-ray regime, development of femtosecond X-ray source is crucial for application in ultrafast science.

ROPA010 Component/Connection/Signal Modeling of Accelerator Systems power-supply, vacuum, controls 707
  • D. Dohan
    ANL, Argonne, Illinois
  Funding: Work supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

This paper presents a pragmatic global approach to data modeling a complex facility such as a particle accelerator. By successively partitioning the facility into collaborating subsystems, one eventually arrives at the component level–the point at which the subsystem is replaceable as a single unit. The fundamental goal of the model is to capture the dynamical relationships (i.e., the connections) that exist among the accelerator components. Components participate in one or more of three connection types: control, housing, and power. These connections are captured in a multi-hierarchical model capable of handling any component of the accelerator, from the macro scale (magnets, power supplies, racks, etc.) to the embedded scale (circuit board components), if desired. The connection approach has been used to model the signal flows between the component via their port connections. The result is a schema for a cable database that provides end-to-end signal tracing throughout the facility. The paper will discuss the multi-hierarchy nature of the model and its success in replacing the "Revision Controlled Drawing" approach to system documentation.

FPAE053 Isobar Suppression by Photodetachment in a Gas-Filled RF Quadrupole Ion Guide ion, rfq, laser, quadrupole 3250
  • Y. Liu, J.R. Beene, C.C. Havener, J. F. Liang
    ORNL, Oak Ridge, Tennessee
  • A.C. Havener
    University of Tennessee, Knoxville, Tennessee
  Funding: Managed by UT-Battelle, LLC, for the U.S. DOE under contract DE-AC05-00OR22725. Co-author Aaron Havener was under a U.S. DOE Science Undergraduate Laboratory Internship.

A novel method is described for selective suppression of isobar contaminants in negative radioactive ion beams. Negative ion beams extracted from an ion source were decelerated to low energies and injected into a gas-filled radio-frequency quadrupole (RFQ) ion guide where the ions were cooled and unwanted ions were selectively removed by non-resonant photodetachment with photons of sufficient energy. Simulation studies show that the laser-ion interaction time in a 40 cm long RFQ ion guide can be on the order of milliseconds, thus, high efficiency photodetachment is possible with commercially available CW lasers. There are a number of adjacent-Z species whose negative ions are such that photodetachment can be used to suppress the unwanted negative ion species while leaving the species of interest intact. Examples of particular interest include suppressing the 56Co- component in a mixed 56Ni- + 56Co- beam and the 17O- component in a mixed 17O- + 17F- beam. In a proof–of-principle experiment a CW Nd:YAG laser at 1064 nm wavelength was used to selectively remove Co- ions in the (Ni, Co) pair. With laser power on the order of 3 W, 95% of Co- beams were suppressed while only 10% of Ni- beams were neutralized in a He-filled RFQ guide.

FPAP002 Experimental Determination of E-Cloud Simulation Input Parameters for DAFNE electron, simulation, vacuum, radiation 817
  • C. Vaccarezza, R. Cimino
    INFN/LNF, Frascati (Roma)
  • A. Giglia, N. Mahne
    ELETTRA, Basovizza, Trieste
  • S. Nannarone
    UNIMORE, Modena
  After the first experimental observations compatible with the presence of the electron-cloud effect in the DAFNE positron ring, an experimental campaign has been started to measure realistic parameters to be used in the simulation codes. Here we present a synchrotron radiation experiment on the photon reflectivity from the actual Al vacuum chamber of DAFNE (same material, roughness and surface cleaning as the one used to manufacture the ring) in the same energy range of photons produced by the accelerator itself. The derived experimental parameter has than been included in the e-cloud simulation codes and the obtained results confirm the relevance of the detailed knowledge of the input parameter to obtain reliable e-cloud simulations.  
FPAT057 A TCL/TK Widget for Display of MEDM Screens monitoring, background 3393
  • R. Soliday
    ANL, Argonne, Illinois
  Funding: This work is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

A new Tcl/Tk widget has been created to display MEDM screens inside a Tcl/Tk application. Tcl/Tk parses the MEDM input files and the appropriate widgets are created and linked to the associated process variables. One advantage of this approach is that an X-Windows emulator is not required to view and manipulate the MEDM screen under a Windows operating system. Another benefit is that the MEDM screen can now be tightly integrated into a scripting language to attach higher-level logic to various process variable manipulations. Further details and examples of the new widget will be discussed.

FPAT058 Creating EPICS Soft Channels the Easy Way with sddspcas: Features and Applications quadrupole, simulation, emittance, lattice 3429
  • R. Soliday, M. Borland
    ANL, Argonne, Illinois
  Funding: This work is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

Using sddspcas, a portable channel access server that is configured by SDDS input files, it is relatively simple to create process variables (PVs). It can be run in a standalone mode or it can be run so that the PVs are checked to ensure that they don’t conflict with other IOCs or portable channel access servers. It can also be run using the Run Control facility to prevent additional instances of the same sddspcas from being run. The SDDS configuration file provides the PV names, upper and lower limits, units, element counts if the PVs are waveforms, and the types of PVs. Valid types include various precision floats and integers as well as strings. One simple application of this program is that software developers can quickly test their code without requiring the coordination needed to update an IOC database to create PVs. Further details of the features, configuration, and applications of sddspcas will be discussed.

FPAT064 Experience with the EPICS PV Gateway at the APS controls, monitoring 3621
  • K. Evans, M. Smith
    ANL, Argonne, Illinois
  Funding: Work supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38.

The EPICS PV Gateway has become a stable, high-performance application that provides access to process variables while minimizing the impact on critical IOCs and implementing additional access security. The additional access security typically prevents write access but is highly configurable. The Advanced Photon Source (APS) currently uses 40 Gateways running on 11 machines to provide access to the machine network from the offices and for the individual experimental teams. These include reverse Gateways that allow administration of all 40 APS Gateways from a single MEDM screen, even though the Gateways are running on separate networks. This administration includes starting, stopping, making and viewing reports, and viewing and editing access security files. There is one Gateway that provides process variable renaming. This paper provides an overview of the Gateways at the APS and describes the procedures that have been set up to use and administer them.

FPAT072 The Status of HLS Control System power-supply, storage-ring, linac, feedback 3862
  • G. Liu, X. Bao, C. Li, W. Li, J. Wang, Xie. Xie, K. Xuan
    USTC/NSRL, Hefei, Anhui
  • J. Li
    DU/FEL, Durham, North Carolina
  HLS (Hefei Light Source) at NSRL (National Synchrotron Radiation Lab) consists of three parts: 200Mev Linac, transport line and 800Mev storage ring. The control system was upgraded based on EPICS (Experimental Physics and Industrial Control system) from 1999 to 2004. This paper will cover the experience of using PC-based hardware under EPICS, data archiving, and some high level tools for physics and operation use.  
FPAT077 An Accelerator Control Middle Layer Using Matlab simulation, lattice, alignment, feedback 4009
  • G.J. Portmann
    LBNL, Berkeley, California
  • W.J. Corbett, A. Terebilo
    SLAC, Menlo Park, California
  Funding: U.S. Department of Energy under Contract No. DEAC03-76SF00098.

Matlab is a matrix manipulation language originally developed to be a convenient language for using the LINPACK and EISPACK libraries. What makes Matlab so appealing for accelerator physics is the combination of a matrix oriented programming language, an active workspace for system variables, powerful graphics capability, built-in math libraries, and platform independence. A number of software toolboxes for accelerators have been written in Matlab – the Accelerator Toolbox (AT) for machine simulations, LOCO for accelerator calibration, Matlab Channel Access Toolbox (MCA) for EPICS connections, and the Middle Layer. This paper will describe the MiddleLayer software toolbox that resides between the high-level control applications and the low-level accelerator control system. This software was a collaborative effort between ALS and Spear but was written to easily port. Five accelerators presently use this software – Spear, ALS, CLS, and the X-ray and VUV rings at Brookhaven. The Middle Layer functionality includes energy ramp, configuration control, global orbit correction, local beam steering, insertion device compensation, beam-based alignment, tune correction, response matrices, and script-based physics studies.

FOAB005 Technology for Fissionable Materials Detection by Use of 100 MeV Variable Linac electron, linac, background, simulation 446
  • S.P. Karasyov, A.N. Dovbnja, L. Eran, Y.P. Melnik, Y. Ran'iuk, I.N. Shlyakhov
    NSC/KIPT, Kharkov
  • A.J. Baratta
    Penn State University, University Park, Pennsylvania
  • N.M. Kiryukhin
    ATSU, Kiev
  • S.V. Trubnikov
    KhNU, Kharkov
  Funding: This project is funded by CRDF FSTM UKE2-5023-KH-04.

A new concept for a two-step facility to increase the accuracy/reliability of detecting heavily shielded fissionable materials (FM) in marine containers is presented. The facility will detect FM in two steps. An existing dual-view; dual-energy X-ray scanner, which is based on 7 MeV electron accelerator, will select the suspicious places inside container. The linac with variable energy (up to 100 MeV) will be used for the second step. The technology will detect fissionable nuclei by gamma induced fission reactions and delayed neutron registration. A little-known Ukrainian experimental data obtained in Chernobil’ clean-up program will be presented to ground proposed concept. The theoretical calculations of neutron fluxes scale these results to marine container size. Modified GEANT code for electron/gamma penetration and authors’ own software for neutron yield/penetration are used for these calculations. Available facilities (X-ray scanners; linac; detectors), which will be used for concept proof, are described. The results of the first experiments by use variable energy linac are cited.