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MOYCH01 The TESLA XFEL Project electron, linac, undulator, laser 11
 
  • H. Weise
    DESY, Hamburg
  The overall layout of the X-Ray FEL to be built in international collaboration at DESY will be described. This includes the envisaged operation parameters for the linear accelerator which will use TESLA technology. Main emphasis is put on the specification of the superconducting accelerator modules. Other linac components will be described as well. Work packages needed to finalize the linac design will be presented. A summary of the status of the preparation work will be given.  
Video of talk
Transparencies
 
MOPKF008 The BESSY Soft X-ray FEL User Facility undulator, simulation, laser, electron 312
 
  • D. Krämer
    BESSY GmbH, Berlin
  A FEL User Facility for the VUV to soft X-ray spectral range is planned at the BESSY site based on a cascaded HGHG-FEL scheme. Simultaneous operation of 3 - later 5 - FELs fed by a superconducting 2.3 GeV CW linac generates most flexible pulse structures for experiments, while the seeding scheme utilizing Ti:Sa fs-lasers results in ultrashort reproducible circular polarized FEL pulses on a shot to shot basis at a pulse-duration < 20 fs. Peak brilliances in the 1·1031 ph/(s mm2 mrad2 0.1% bw)-regime are feasible. All necessary hardware for the FEL is within existing technology. Future upgrade options, e.g. a superconducting photoinjector, seeding with short wavelength HHG lasers of about 1 fs pulse duration have been considered. A status on the design aspects is given.  
 
MOPKF032 Status of the ESRF Insertion Devices undulator, insertion, insertion-device, radiation 372
 
  • J. Chavanne, C. Penel, B. Plan, F. Revol
    ESRF, Grenoble
  The ESRF insertion devices are the object of a continuous refurbishment in order to follow the changing needs of the beamlines and increase their performances. The successful development of the narrow aperture aluminum chambers pumped by non evaporable getter has resulted in the reduction of the minimum gap from 16 mm to 11 mm . A new set of undulator magnetic assemblies with shorter magnetic periods are being prepared that make use of the lower gap. .A prototype of a new type of revolver undulator support has been completed and successfully tested. Such a structure allows the beamline user to switch between two different undulator periods in less than a minute. Three additional devices will be constructed in 2004. Three new in-vacuum undulators have been installed on the ring. One of them is based on an hybrid magnetic structure and achieves a peak field 20% higher than a pure permanent magnet undulator of identical period. Their main magnetic measurements results and interactions with the stored beam are presented.  
 
MOPKF064 Design Considerations for a Helical Undulator for the Production of Polarised Positrons for TESLA undulator, positron, electron, permanent-magnet 458
 
  • D.J. Scott, S.C. Appleton, J.A. Clarke, B. Todd
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • E. Baynham, T.W. Bradshaw, S.C. Carr, Y. Ivanyushenkov, J. Rochford
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  An efficient and simple method for the production of positrons, in the necessary quantities, is one of the problems facing proposals for any future e+ e- Linear Collider project. The possibility of colliding polarised beams would also be an advantage. One method to produce a polarised positron beam uses circularly polarised radiation generated by the main electron beam passing through a helical undulator. Design considerations and calculations for two undulators, based on super-conducting and pure permanent magnet technologies, for the TESLA machine, are presented.  
 
MOPKF068 Experimental Study of the Stability Margin with Beam Heating in a Short-Period Superconducting Undulator for the APS vacuum, undulator, storage-ring, synchrotron 470
 
  • S.H. Kim, C. Doose, R. Kustom, E.R. Moog, K.M. Thompson
    ANL/APS, Argonne, Illinois
  A superconducting undulator with a period of 15 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 tip gap and an NbTi coilpack current density of 1 kA/mm2. Because of the high current density in the coilpack, the superconducting magnet operates at about 75% of the short sample limit at 4.2K. Additional heat load to the coilpack, mainly due to the image currents and synchrotron radiation from the electron beam in the storage ring, will reduce the stability margin. An experiment was conducted to measure the reduction in the stability margin of the coilpack due to heat load on the beam chamber. The heat load was deposited in a 12-period prototype undulator using thin-film heaters attached to the inner surface of a simulated vacuum chamber. Evaluation of the stability margin based on the experiment and calculations of the beam heating and thermal conduction between the undulator and beam chamber will be discussed.  
 
MOPLT061 Design Study for Advanced Acceleration Experiments and Monochromatic X-ray Production @ SPARC laser, electron, plasma, acceleration 695
 
  • L. Serafini, S. Cialdi, R. Pozzoli, M. Romé
    INFN-Milano, Milano
  • D. Alesini, S. Bertolucci, M.E. Biagini, C. Biscari, R. Boni, M. Boscolo, M. Castellano, A. Clozza, G. Di Pirro, A. Drago, A. Esposito, M. Ferrario, V. Fusco, A. Gallo, A. Ghigo, S. Guiducci, M. Incurvati, C. Ligi, F. Marcellini, M.  Migliorati, C. Milardi, L. Palumbo, L. Pellegrino, M.A. Preger, P. Raimondi, R. Ricci, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, F. Tazzioli, C. Vaccarezza, M. Vescovi, C. Vicario, M. Zobov
    INFN/LNF, Frascati (Roma)
  • F. Alessandria, A. Bacci, F. Broggi, C. De Martinis, D. Giove, M. Mauri
    INFN/LASA, Segrate (MI)
  • R. Bonifacio, I. Boscolo, C. Maroli, V. Petrillo, N. Piovella
    Universita' degli Studi di Milano, MILANO
  • A. Mostacci
    Rome University La Sapienza, Roma
  We present a design study for an upgrade of the SPARC photo-injector system, whose main aim is the construction of an advanced beam test facility for conducting experiments on high gradient plasma acceleration and for the generation of monochromatic X-ray beams to be used in advanced medical applications and condensed matter physics studies. Main components of the proposed plan of upgrade are: two additional beam lines with interaction regions for synchronized high brightness electron and high intensity photon beams and the upgrade of the SPARC Ti:Sa laser system to reach a multi-TW power level (in excess of 1 J in pulse energy). Results of numerical simulations modeling the interaction of the SPARC electron beam and the counter-propagating laser beam are presented with detailed discussion of the monochromatic X-ray beam spectra generated by Compton backscattering: X-ray energies are tunable in the range 20 to 500 keV, with pulse duration from sub-ps to 30 ps. Preliminary simulations of plasma acceleration of the SPARC electron beam, generated in ultra-short bunches, via the LWF mechanism and with external injection are also shown: experiments of self-injection are also foreseen and illustrated.  
 
MOPLT069 Investigation of Injection for the Low-emittance Lattice with New-6.25 ohm Kicker Magnet System at the Photon Factory kicker, injection, factory, lattice 710
 
  • A. Ueda, K. Harada, Y. Kobayashi, T. Mitsuhashi
    KEK, Ibaraki
  We installed 6.25ohm traveling-wave kicker magnet in the Photon Factory to obtain a wide acceptance for the injected beam into the low-emittance lattice of the Photon Factory. We investigate the injection for the low-emittance lattice with this 6.25ohm kicker magnet system. Hence we have optical beam diagnostic systems which source point is inside of injection bump, we use this system for the investigation of injection. The pulse shape of the injection bump was measured by the optical beam profile monitor with high-speed gated camera by using a stored beam. The result of pulse shape of injection bump was agreed with the predicted one by using result of magnetic field measurement, and pulse duration was shorter than twice of revolution time. The instantaneous beam profile of injected beam was observed in turn by turn by using the same beam profile monitor system. We measure the turn by turn position of the injected beam from this observation and compare with a simulation. We also observe a smear out of beam oscillation by nonlinear effect from this instantaneous beam profile measurement.  
 
MOPLT128 Lattice Effects due to High Currents in PEP-II sextupole, luminosity, emittance, synchrotron 836
 
  • F.-J. Decker, H. Smith, J.L. Turner
    SLAC, Menlo Park, California
  The very high beam currents in the PEP-II B-Factory have caused many expected and unexpected effects: Synchrotron light fans move the beam pipe and cause dispersion, higher order modes cause excessive heating, e-clouds around the positron beam blow up its beam size. Here we describe an effect were the measured dispersion of the beam in the Low Energy Ring (LER) is different at high and at low beam currents. The dispersion was iteratively lowered by making anti-symmetric orbit bumps in many sextupole duplets, checking each time with a dispersion measurement where a dispersive kick is generated. This can be done parasitically during collisions. It was a surprise when checking the low current characterization data that there is a change. Subsequent high and low current measurements confirmed the effect. It is located far away from any synchrotron radiation in the middle of a straight (PR12), away from sextupoles and skew quadrupoles and creates a dispersion wave of about 70 mm at high current while at low current it is negligible.  
 
TUZACH01 Positron Source Options for Linear Colliders positron, target, radiation, electron 69
 
  • K. Floettmann
    DESY, Hamburg
  Linear colliders require sources delivering particle intensities much higher than sources for storage rings and even several orders of magnitude larger than the SLC positron source, the highest intensity positron source operated so far. A fundamental limitation for the intensity of a positron source is set by the thermal stress in the target. Besides improvements of conventional positron sources, i.e. sources where an electron beam creates electron position pairs in an electromagnetic cascade, new concepts based on the direct conversion of gamma radiation offer possibilities for increased particle intensities. In these sources the hard gamma radiation has to be produced either in an undulator or by backscattering of laser light off an electron beam. An additional advantage of gamma radiation based sources is the possibility to produce polarized positrons. The talk will give an overview of the developments of high intensity unpolarized and polarized positron sources for linear colliders.  
Video of talk
Transparencies
 
TUPLT128 The Operation Modes of Kharkov X-ray Generator based on Compton Scattering NESTOR electron, laser, storage-ring, scattering 1428
 
  • A.Y. Zelinsky, E.V. Bulyak, P. Gladkikh, I.M. Karnaukhov, A. Mytsykov, A.A. Shcherbakov
    NSC/KIPT, Kharkov
  • T.R. Tatchyn
    SLAC/SSRL, Menlo Park, California
  The results of theoretical and numerical considerations of linear Compton scattering are used to evaluate characteristics of X-rays produced by collision between a low emittance electron beam and intensive laser light in an X-rays generator NESTOR of NSC KIPT. Two main generation modes have been under consideration at preliminary NESTOR design. There are the operation mode for medicine 33.4 keV X-rays production using 43 Mev electron beam and Nd:YAG laser beam and higher energy X-rays production mode providing X-rays with energy up to 900 keV with 225 MeV electron beam and Nd:YAG laser beam. It is supposed to use an optical cavity for laser beam accumulation of about 2.6 m long and an interaction angle of about 30 in both operation modes. A few more operation modes provide possibility to expand operation range of NESTOR. Using interaction angle 100 and 1500 along with optical resonator 42 or 21 cm long and the second mode of laser light it is possible to produce X-rays in energy range from a few keV till 1.5 MeV. The intensity and spectral brightness of the X-rays is expected to be ~ 1013 phot/s and ~ 1013 phot/s/mm2/mrad2/0.01%BW respectively.  
 
WEPKF021 Non-destructive Testing of Bus-bar Joints Powering LHC Superconducting Magnets, by Using Gamma Sources quadrupole, dipole, superconducting-magnet, target 1642
 
  • B. Skoczen
    CERN, Geneva
  • J. Kulka
    AGH, Cracow
  The main LHC superconducting magnets (dipoles and quadrupoles) are powered by using Rutherford type cables, stabilized electrically and thermally with copper profiles. The portions of cables are connected to each other by a soft soldering technique (Sn96Ag4) with the overlapping length corresponding to one pitch of the superconducting strands. The splice constitutes a ?composite? structure with the interchanging layers of Sn96Ag4 and NbTi superconductor, located inside a Cu cage. In order to assure a high level of reliability (failure probability not exceeding 10-8) for some 10000 connections in the LHC, a non-destructive technique of checking the quantity of solder in the joint is planned to be implemented. The technique is based on a gamma ray source (241_Am) and the detection is position-sensitive in the transmission mode. 5 scintillating detectors of gamma rays are used and their accumulated length corresponds to the length of the radioactive source (120 mm). The method can be used in-situ, the equipment being optimized and portable, with implementation of direct on-line operation mode. The relevant criteria of acceptance of the splices have been defined. The first results of application of this technique will be shown.  
 
WEPKF042 Installation and Operation of New Klystron Power Supply with Fast Solid-State Switch for Klystron Protection at the Photon Factory Storage Ring power-supply, klystron, factory, storage-ring 1699
 
  • S. Sakanaka, M. Izawa, T. Takahashi, K. Umemori
    KEK, Ibaraki
  In the 2.5-GeV Photon Factory storage ring at KEK, there are four klystron power supplies which typically operate at an output voltage of -40 kV with 8 A. We replaced one of these power supplies during 2003 and the new power supply is in operation. This power supply is equipped with a solid-state high-voltage (HV) switch for klystron protection. This HV switch is made up of eighty insulated gate bipolar transistors (IGBT), and it can turn the high-voltage off within a few tens of microseconds in cases of any discharges in the klystrons. We report the performance of this new power supply.  
 
WEPKF043 Measurement of the Vertical Quadrupolar Tune Shift in the Photon Factory Storage Ring storage-ring, betatron, single-bunch, factory 1702
 
  • S. Sakanaka, T. Mitsuhashi, T. Obina
    KEK, Ibaraki
  We measured the frequencies of vertical quadrupole oscillations in the 2.5-GeV Photon Factory storage ring at KEK. The measured vertical quadrupole tunes showed remarkable dependence of about -7.5E-5/mA on the bunch current. This contrasts with our previous result of about +4.8E-5/mA (presented in PAC2003) for the horizontal quadrupole tune shift. These results will suggest that the transverse wake forces in a quadrupolar mode contribute significantly to the transverse motions of particles in the Photon Factory storage ring.  
 
WEPKF071 A New Current Regulator for the APS Storage Ring Correction Magnet Bipolar Switching Mode Power Converters storage-ring, power-supply, controls 1768
 
  • J. Wang
    ANL, Argonne, Illinois
  The correction magnets in the Advanced Photon Source's storage ring are powered by PWM-controlled bipolar switching-mode converters. These converters are designed to operate at up to ± 150 A. The original current regulator used a polarity detection circuit, with a hysteresis, to determine which IGBT was needed to regulate the current with a given polarity. Only the required IGBT was switched while others were held on or off continuously. The overall IGBT switching losses were minimized by the design. The shortcoming of the design is that the converter's output is unstable near zero current because of the hysteresis. To improve the stability, a new current regulator, using a different PWM method, has been designed to eliminate the requirement of the polarity detection. With the new design, converters can operate smoothly in the full range of ±150 A. The new design also meets tighter specs in terms of the ripple current and dynamic response. This paper describes the design of the new regulator and the test results.  
 
WEPLT033 The LHC Radiation Monitoring System for the Environment and Safety radiation, monitoring, radioactivity, instrumentation 1903
 
  • L. Scibile, D. Forkel-Wirth, H.G. Menzel, D. Perrin, G. Segura Millan, P. Vojtyla
    CERN, Geneva
  A state of the art radiation monitoring and alarm system is being implemented at CERN for the LHC. The RAdiation Monitoring System for the Environment and Safety (RAMSES) comprises about 350 monitors and provides ambient dose equivalent rates measured in the LHC underground areas as well as on the surface inside and outside the CERN perimeter. In addition, it monitors air and water released from the LHC installations. Although originally conceived for radiation protection only, RAMSES also integrates some conventional environmental measurements such as physical and chemical parameters of released water and levels of non-ionizing radiation in the environment. RAMSES generates local radiation warnings, local alarms as well as remote alarms on other monitored variables, which are transmitted to control rooms. It generates operational interlocks, allows remote supervision of all measured variables as well as data logging and safe, long-term archiving for off-line data analysis and reporting. Requirements of recent national and international regulations in combination with CERN's specific technical needs were translated into the RAMSES specifications. This paper outlines the scope, the organization, the main system performance and the system design.  
 
WEPLT106 Growth and Suppression Time of an Ion-related Vertical Instability octupole, factory, storage-ring, betatron 2098
 
  • T. Miyajima, Y. Kobayashi, S. Nagahashi
    KEK, Ibaraki
  In the KEK Photon Factory electron storage ring, a vertical instability has been observed in a multi-bunch operation mode. The instability can be suppressed by octupole magnetic field in routine operation. Since the instability depends on a vacuum condition in the ring, it seems that it is an ion-related phenomenon. In order to study this instability, we measured the growth and the suppression time of it with the pulse octupole magnet system, which can produce the octupole field with rise and fall time of around 1.2msec. We obtained the result that the instability was grown slowly compared with to suppress it, and the growth time depended on the fill pattern of the bunch train and the beam current per bunch.  
 
WEPLT140 New Abilities of Computer Code DeCA scattering, electron, simulation, laser 2164
 
  • P. Gladkikh, A.Y. Zelinsky
    NSC/KIPT, Kharkov
  In the paper the status and new abilities of computer code package DeCA (Design of Cyclic Acclerators) are described. The main effort of the code developers were made to creation of software capable to simulate intrabeam scattering effect and Compton scattering. In addition modules for calculation of the second order dispersion and momentum compaction factor were developed.  
 
THXCH01 Achieving Sub-micron Stability in Light Sources feedback, quadrupole, storage-ring, resonance 211
 
  • M. Böge
    PSI, Villigen
  One of the major goals for present and future light sources is to achieve sub-micron orbit stability of the electron beam at the photon beam source points over a large frequency range. This puts tight constraints on the design of the various accelerator components like girders, magnets, power supplies and diagnostic hardware. Fast orbit feedbacks systems based on high performance RF- and X-BPMs become essential to suppress residual orbit distortions. Furthermore the "top-up" operation mode which guaranties a constant electron beam current and thus a constant heat load in 3rd generation light sources is one of the key ingredients to reach sub-micron stability.  
Video of talk
Transparencies
 
THYCH01 Issues and Challenges for Short Pulse Radiation Production electron, laser, radiation, linac 225
 
  • P. Emma
    SLAC/ARDA, Menlo Park, California
  A new generation of light sources are being planned at many locations, pushing the frontiers of brightness, wavelength, and peak power well beyond existing 3rd generation sources. In addition to these large scale improvements there is great interest in extremely short duration pulses into the femtosecond and sub-femtosecond regime. Collective electron bunch instabilities at these scales are severe, especially in consideration of the high-brightness electron bunch requirements. Several new schemes propose very short radiation pulses generated with moderate electron bunch lengths. Such schemes include radiation pulse compression, differential bunch spoiling, staged high-gain harmonic generation, and selective pulse seeding schemes. We will describe a few of these ideas and address some of the electron bunch length limitations, highlighting recent measurements at the Sub-Picosecond Pulse Source (SPPS) at SLAC where <100-fs electron and x-ray pulses are now available.  
Video of talk
Transparencies
 
THYLH01 Beam Diagnostics at the VUV-FEL Facility radiation, electron, diagnostics, laser 262
 
  • J. Feldhaus, D. Noelle
    DESY, Hamburg
  The free electron laser (FEL) at the TESLA Test facility at DESY will be the first FEL user facility for VUV and soft X-ray radiation down to 6 nm wavelength, the commissioning starts in summer 2004. Commissioning as well as stable FEL operation require a combination of different diagnostic tools for measuring both electron and photon beam parameters, including the full phase space distribution of the bunch charge, exact timing with sub-picosecond resolution, electron and photon beam overlap along the undulator, radiation beam position in the user area 50-70 m behind the undulator, intensity and spectral distribution of the radiation pulses and others. Much effort has been put in the development of instrumentation for measuring the longitudinal bunch charge distribution, for controlling the electron beam orbit along the undulator, and for online monitoring the radiation intensity, position and spectral distribution. This contribution gives an overview of the complete electron and photon beam diagnostics of the FEL facility and focuses particularly on the instrumentation which is crucial or specific for the FEL operation.  
Video of talk
Transparencies
 
THOBLH02 Ultrafast Compton Scattering X-Ray Source Development at LLNL electron, laser, scattering, interaction-region 270
 
  • F.V. Hartemann, S. Anderson, C.P.J. Barty, S.M. Betts, R. Booth, J. Brown, K. Crane, R.R. Cross, D.N. Fittinghoff, D. Gibson, E.P. Hartouni, J. Kuba, G.P. Le Sage, D.R. Slaughter, P.T. Springer, A. Tremaine, A.J. Wootton
    LLNL, Livermore, California
  • J. Rosenzweig
    UCLA, Los Angeles, California
  The LLNL PLEIADES (Picosecond Laser-Electron Inter-Action for the Dynamical Evaluation of Structures) facility is now operating between 30 and 80 keV, and produces > 5 x 106 photons per shot at 10 Hz. This important milestone offers a new opportunity to develop laser-driven, compact, tunable x-ray sources for critical applications such as NIF diagnostics, time-resolved material studies, and advanced biomedical imaging. Initial x-rays were captured with a CCD using a CsI scintillator; the photon energy was measured at approximately 70 keV, and the observed spectral and angular distributions found to agree very well with three-dimensional codes. The electron beam was focused to 30 um rms, at 54 MeV, with 250 pC of charge, a relative energy spread of 0.2%, and a normalized emittance of 10 mm.mrad. Optimization of the x-ray dose is currently underway, with the goal of reaching 107 photons per shot and a peak brightness approaching 1017 photons/mm2/mrad2/s/0.1%bandwidth. High-Z K-edge radiographs have been demonstrated, as well as diffraction using highly-ordered pyrolytic graphite crystals. Nonlinear scattering experiments, using a tightly focused laser spot will also be discussed, as well as plans to develop a source capable of reaching 1% conversion efficiency from the electron beam kinetic energy into x-rays, and ultrafast diffraction experiments.  
Video of talk
Transparencies
 
THOBLH03 BESSY II Operated as a Primary Source Standard electron, storage-ring, radiation, synchrotron 273
 
  • R. Klein, R. Thornagel, G. Ulm
    PTB, Berlin
  The Physikalisch-Technische Bundesanstalt (PTB) is the German National Metrology Institute and responsible for the realization and dissemination of the legal units in Germany. For the realization of the radiometric units in the VUV and X-ray spectral range PTB has been using calculable synchrotron radiation of bending magnets from the BESSY I and BESSY II electron storage rings for more than 20 years. The spectral photon flux of synchrotron radiation can be precisely calculated by Schwinger's theory. Therefore, all the storage ring parameters entering the Schwinger equation have to be measured with low uncertainty which requires a stable and reproducible operation of the storage ring. At BESSY II, PTB has installed all equipment necessary to measure the electron energy, the electron beam current, the effective vertical source size and the magnet induction at the radiation source point as well as all geometrical quantities with low uncertainty. The measurement accuracy for these quantities enables PTB to calculate the spectral photon flux from the visible up to the soft X-ray range with relative uncertainties below 0.4 %. We report on the measurement of the storage ring parameters with low uncertainty.  
Video of talk
Transparencies
 
THPKF001 Status of 3 GeV CANDLE Synchrotron Light Facility Project brightness, synchrotron, scattering, emittance 2254
 
  • V.M. Tsakanov, M. Aghasyan, G. Amatuni, V.S. Avagyan, A. Grigoryan, B. Grigoryan, M. Ivanyan, V. Jalalyan, D.K. Kalantaryan, V.G. Khachatryan, E.M. Laziev, Y.L. Martirosyan, R.H. Mikaelyan, S. Minasyan, K.N. Sanosyan, S. Tatikian, S. Tunyan, A. Vardanyan
    CANDLE, Yerevan
  CANDLE- Center for the Advancement of Natural Discoveries using Light Emission – is a 3 GeV third generation synchrotron light facility project in Republic of Armenia. The presentation includes the main considerations that underlie the Conceptual Design Report of the project and the progress made after the last EPAC conference. An overview of machine and beam physics study, the prototype and laboratory development is given.  
 
THPKF016 The Metrology Light Source of the Physikalisch-Technische Bundesanstalt in Berlin-Adlershof electron, radiation, storage-ring, synchrotron 2293
 
  • R. Klein, G. Ulm
    PTB, Berlin
  • M. Abo-Bakr, P. Budz, K. Bürkmann, D. Krämer, J. Rahn, G. Wustefeld
    BESSY GmbH, Berlin
  PTB, the German National Metrology Institute, has gained approval for the construction of a low-energy electron storage ring in the close vicinity of BESSY II, where PTB operates a laboratory for X-ray radiometry. The new storage ring, named 'Metrology Light Source MLS' will be dedicated to metrology and technology development in the UV and EUV spectral range and so will fill the gap that is present since the shut down of BESSY I. The MLS is designed in close cooperation with BESSY and is located adjacent to the BESSY II facility. Construction will start 2004 and user operation is scheduled to begin in 2008. The MLS has a circumference of 48 m, injection will be from a 100 MeV microtron. The electrons energy is ramped to an eligible value in the range from 200 MeV to 600 MeV. The MLS will be equipped with all the instrumentation necessary to measure the storage ring parameters needed for the calculation of the spectral photon flux according to the Schwinger theory with low uncertainty, enabling PTB to operate the MLS as a primary source standard. Moreover, provision is taken to operated the MLS in a low alpha mode for the production of coherent synchrotron radiation in the far IR and THz region.  
 
THPKF020 Improvements of the Orbit Stability at DORIS III feedback, synchrotron, radiation, synchrotron-radiation 2305
 
  • F. Brinker, O. Kaul
    DESY, Hamburg
  Running since 1974, the storage ring DORIS experienced a major modification in 1991 to run as a dedicated synchrotron radiation source since 1993. Since then the increasing requirements of the users on beam stability lead to a series of technical and operational measures to improve the beam conditions. The beam pipe has been mechanically isolated from the magnets, the cooling has been improved and this year a new orbit feedback came to operation which uses positron beam position monitors as well as photon monitors in the beam lines to stabilise the different photon beams. The different measures taken are presented.  
 
THPKF029 Femto-second Electron Beam Slicing Project at SOLEIL electron, laser, separation-scheme, undulator 2332
 
  • O.V. Chubar, M. Idir, M.-P. Level, A. Loulergue, T. Moreno, A. Nadji, L.S. Nadolski, F. Polack
    SOLEIL, Gif-sur-Yvette
  The goal of the slicing project at SOLEIL is to provide short (50-100 fs) soft and hard X-rays pulses. The principle is based on the technique demonstrated earlier at ALS. In our case, the naturally suitable phase advances and the horizontal distributed dispersion enable the sliced pulse to be used on several consecutive straight sections. Further separation between the core and the sliced electron beams is obtained by increasing the effective horizontal dispersion using a chicane bracketing the modulator. In the hard X-rays case, the photon beams are separated spatially using a simple slit in a pinhole-camera type configuration while a mixed spatial-angular separation is chosen for the soft X-rays case. This minimizes the amount of parasitic core radiation scattered from the surface of the first focusing mirror. We will first describe the proposed scheme, the impact on the machine and some other issues. Then, photon optics calculation is presented. This takes into account the SOLEIL magnet lattice, realistic parameters of a femto-second laser, peculiarities of spectral distributions of undulator radiation and its diffraction in the range of intensities covering several orders of magnitude.  
 
THPKF034 Design of a Photoneutron Source based on a 5 MeV Electron Linac target, electron, linac, simulation 2347
 
  • L. Auditore, R.C. Barnà, D. De Pasquale, A. Trifirò, M. Trimarchi
    INFN & Messina University, S. Agata, Messina
  • A. Italiano
    INFN - Gruppo Messina, S. Agata, Messina
  A photoneutron source, based on a 5 MeV electron linac was designed by means of the MCNP simulation code. Although higher electron energies are required to produce acceptable neutron fluxes, the availability of a 5 MeV electron linac developed at the Dipartimento di Fisica (Università di Messina) has suggested this project, in sight of a future development and testing of the studied neutron source. Be and BeD2 targets were considered, whose neutron production was studied optimizing two sequential steps: the bremsstrahlung production in a suitable e-gamma converter and the (gamma,n) production in an properly designed photoneutron target-reflector-moderator system. As a result of a comparative study of different materials performances, a 0.88 mm-thick W layer was chosen as e-gamma converter. A natural graphite reflector was designed, surrounding the target, enhancing the neutron flux of two order of magnitude. The final neutron flux, at 50 cm from the photoneutron target, thermalized by a 12.2 cm-thick PE layer, was estimated to be 8.48E+07 n/cm2/sec/mA with Be target and 1.23E+08 n/cm2/sec/mA with BeD2 target.  
 
THPKF046 Feasibility Study of Constant Current Operation at TLS Storage Ring injection, storage-ring, insertion, insertion-device 2380
 
  • G.-H. Luo, H.-P. Chang, J. Chen, C.-C. Kuo, K.-B. Liu, R.J. Sheu, H.-J. Tsai, M.-H. Wang
    NSRRC, Hsinchu
  Several top-up experiments were carried out at various upgrade path of Taiwan Light Source. However, there were too many obstacles laid ahead of various stages to prevent the realization of top-up injection routinely. The small gap undulators, the requirement of small emittance operation and high current operation by SC cavity have promoted the top-up injection project to hightest priority. During last one and half years, a series of beam parameters measurement, subsystem checkout, installing various sensors, control program modification and hardware upgrade made the top-up injection more likely in routine operation. Discussions on the results of some measurements of booster and storage ring, the requirement of hardware upgrade and the future executable plan will be presented in this paper.  
 
THPKF063 Parameters of X-ray Radiation Emitted by Compton Sources electron, laser, scattering, collimation 2409
 
  • E.V. Bulyak, V. Skomorokhov
    NSC/KIPT, Kharkov
  Presented are results of analytical study on X–ray beam parameters generated in the Compton storage rings. A model with the given circulating electron bunch parameters and the laser splash as well is considered. For this model, the total yield of x–ray quanta is derived as a function of the crossing angle and geometric dimensions of both the bunch and splash. Also spectral characteristics of emitting x–ray beam are evaluated with account for the collimating conditions and both the angular and energy spreads in the bunch. As is shown the width of x–ray energy spectrum is narrowest for the x-ray beam collimated along the bunch orbit. With increasing the scattering angle (with respect to the bunch orbit) the spectrum of emitting quanta is widening. Problems of x-ray beam generation with required energy and brightness with the Compton storage rings are discussed.  
 
THPKF066 Conception of X-ray Source Based on Compact Wakefield Undulator radiation, electron, undulator, RF-structure 2415
 
  • A. Opanasenko
    NSC/KIPT, Kharkov
  Study of interaction of bunched charged ultrarelativistic particles with own wakefields in periodic rf structures detects new applications in the area of accelerator physics and technology. Conception of monochromatic X-ray source based on wakefield undulator, WFU, with very short period is presented. In the base of photon generation by the WFU lies a new mechanism of undulator-type radiation emitted by an ultrarelativistic electron bunch that undulates due to non-synchronous spatial harmonics of its wakefields while the bunch moves along a periodic waveguide. The features of the hard radiation and yield of photons depending on waveguide sizes and charge distribution are considered. The creation of the WFU with sub-millimetre periods due to advanced accelerator technology, such as deep X-ray lithography, opens possibilities to obtain high brightness X-rays at employing comparatively low electron energies without external alternative fields. That can have commercial significance for technological and medical applications.  
 
THPLT023 The Use of Photon Monitors at the Swiss Light Source feedback, insertion, insertion-device, undulator 2520
 
  • J. Krempasky, M. Böge, T. Schilcher, V. Schlott, T. Schmidt
    PSI, Villigen
  The photon beam position monitors (PBPM) in a synchrotron radiation facility are important tools for beam-line and machine diagnostics since they deliver position and angle information directly from the radiation source point. In the last two years a number of PBPMs have been installed and commissioned at the Swiss Light Source (SLS). Their readouts have been systematically studied and the results have been correlated with data from the digital beam position monitor (DBPM) system. It turns out that the PBPMs help understanding the influence of insertion device gap changes on photon beam position and thus on photon flux and/or energy resolution near the beam-line experimental stations. In addition to the global fast orbit feedback (FOFB), a local slow feedback based on PBPM data has been implemented to remove the remaining systematic effects of the DBPM system and to stabilize the photon beam to a micron level at the experimental station.  
 
THPLT024 Commissioning and Operation of the SLS Fast Orbit Feedback feedback, storage-ring, electron, booster 2523
 
  • T. Schilcher, M. Böge, B. Keil, P. Pollet, V. Schlott
    PSI, Villigen
  The SLS Fast Orbit Feedback (FOFB) was successfully commissioned in 2003. Since November 2003 it runs during user operation of the accelerator. Taking into account 72 Digital Beam Position Monitors (DBPMs), the FOFB applies SVD-based global orbit corrections for 72 horizontal (x) and 72 vertical (y) correctors at a rate of 4 kHz, compared to ~0.5 Hz for the Slow Orbit Feedback (SOFB) that was used so far. While the SOFB was important for the elimination of orbit drifts due to temperature changes and slowly moving insertion device (ID) gaps, the FOFB is also able to damp orbit oscillations that are caused by fast changes of ID gaps or magnets, by ground and girder vibrations, 3 Hz booster crosstalk and power supply noise. This report presents experience from commissioning and user operation of the FOFB.  
 
THPLT026 Beam Profile Measurements at PETRA with the Laserwire Compton Scattering Monitor laser, positron, background, collider 2529
 
  • T.  Kamps
    BESSY GmbH, Berlin
  • K. Balewski, H.-C. Lewin, S. Schreiber, K. Wittenburg
    DESY, Hamburg
  • G.A. Blair, G. Boorman, J. Carter, F. Poirier
    Royal Holloway, University of London, Surrey
  • S.T. Boogert
    UCL, London
  • T. Lefevre
    CERN, Geneva
  The vertical beam profile at the PETRA positron storage ring has been measured using a laserwire scanner. A laserwire monitor is a device which can measure high brilliant beam profiles by scanning a finely focused laser beam non-invasively across the charged particle beam. Evaluation of the Compton scattered photon flux as a function of the laser beam position yields the transverse beam profile. The aim of the experiment at PETRA is to obtain the profile of the positron beam at several GeV energy and several nC bunch charge. Key elements of laserwire systems are currently being studied and are described in this paper such as laser beam optics, a fast scanning system and a photon calorimeter. Results are presented from positron beam profile scans using orbit bumps and a fast scanning scheme.  
 
THPLT027 Optical Transition Radiation Based Beam Diagnostics at the BESSY Synchrotron Radiation Source and FEL Accelerators electron, laser, radiation, linac 2532
 
  • T.  Kamps, K. Holldack, P. Kuske
    BESSY GmbH, Berlin
  Optical Transition Radiation (OTR) based diagnostics tools are widely used in linear accelerators to measure beam parameters like transverse beam size and emittance. Design ideas for OTR stations in the linac section of the BESSY FEL facility are presented. Several key components will be tested in the transfer lines of the BESSY storage ring. Furthermore a novel type of OTR monitor is introduced which enables the measurement of the transverse overlap of seed laser and electron beam in the undulator sections of the linac based FEL facility. Here a special radiator screen will be used allowing simultaneous imaging of both beams in the same optical readout channel.  
 
THPLT067 Development of Optical Diffraction Radiation Beam Size Diagnostics at KEK Accelerator Test Facility target, diagnostics, laser, radiation 2646
 
  • V. Karataev, H. Hayano, T. Muto, N. Terunuma, J. Urakawa
    KEK, Ibaraki
  • R. Hamatsu
    TMU, Hatioji-shi,Tokyo
  • A. Naumenko, A.P. Potylitsyn
    Tomsk Polytechnic University, Physical-Technical Department, Tomsk
  Extremely low emittance high current beam is required for the accelerators of the next generation such as linear collider to achieve a reasonable luminosity. However, up to now there is no a simple non-invasive technique for beam diagnostics. A method based on optical diffraction radiation (ODR) appearing when a charged particle passes through a slit between two semi-planes can be one of the promising approaches. The estimations show that it might be possible to measure the beam size as small as 10mcm for a single shot. For a test of the proposed technique we designed an experimental setup and installed it at the extraction line of the KEK-ATF (1.26GeV beam energy, 1010 e/bunch, rms beam size > 10mcm). The electron beam was moving through a 0.26mm wide slit. We have measured backward ODR angular distribution. We have observed the beam size effect on the measured quantities. The sensitivity to the beam size as small as 20mcm was achieved. However, some undesirable factors such as X-ray background, SR photons coming through the mask slit, big detector angular acceptance have to be reduced. In this case a few micrometers beam size could be measured.  
 
THPLT070 Design and Constriction of Coronagraph for Observation of Beam Halo factory, background, optics, scattering 2655
 
  • T. Mitsuhashi
    KEK, Ibaraki
  The coronagraph is a spatial telescope to observe the sun-corona by artificial eclipse. The concept of this apparatus is to realize the Schlieren-optical system for cutting the bright diffraction fringes in order to observe a less-bright object surrounding the main image such as the sun-corona. We applied this concept for the observation of the surrounding structure (halo, tail) of the beam. Since the background is mainly scattered light come from the objective lens, the key point to observe a less-intense object is to reduce scattering light from objective lens. We used a very well-polished lens (better than scratch and dig 20/20) as objective lens, and succeeded to obtain the signal to background ratio better than 10-5. As a test, we tried to observe the tail of beam by hiding the central peak with artificial eclipse by the coronagraph at Photon Factory storage ring. We succeeded to observe the tail of beam which has an intensity range of 1/104 of the peak intensity.  
 
THPLT084 Test Result of Slow Global Orbit Feedback using MATLAB at PLS feedback, power-supply, insertion, insertion-device 2694
 
  • H.-S. Kang, J. Choi, K.M. Ha, E.-H. Lee, T.-Y. Lee, W.W. Lee
    PAL, Pohang
  A slow global orbit feedback using MATLAB has been tested to control the slow orbit movement for the PLS. The feedback program uses MATLAB tools such as matrix algebra, mathematical functions, and graphic display, and uses the SVD (singular value decomposition) method. The PLS uses 70 corrector magnets with the maximum angle of 2-mrad for each plane among which 11 use the 16-bit DAC power supplies for the insertion device orbit control and others the 12-bit corrector power supplies with the minimum step of 1-micro-rad, and thus the orbit feedback is not acceptable to beamline users. For the best performance of the feedback, the major hardware components have been upgraded: the replacement of 12-bit BPMs with 16-bit was completed, and the upgrade of corrector power supplies from DAC 12-bit to 18-bit or higher will be completed soon. In this paper, the orbit feedback test result using the current corrector power supplies is presented and the upgrade plan of orbit feedback is described.  
 
THPLT100 Development of a Permanent Magnet Residual Gas Profile Monitor With Fast Readout electron, ion, synchrotron, injection 2724
 
  • D.A. Liakin, S.V. Barabin, V. Skachkov
    ITEP, Moscow
  • P. Forck, T. Giacomini
    GSI, Darmstadt
  • A. Vetrov
    MSU, Moscow
  The beam profile measurement at modern ion synchrotrons and storage rings require high timing performances on a turn-by-turn basis. From the other hand, high spatial resolutions are very desirable for cold beams. We are developing a residual gas monitor to cover the wide range of beam currents and transversal distributions of particles. It supplies the needed high-resolution and high-speed tools for beam profiling. The new residual gas monitor, will operate on secondary electrons whose trajectories are localized within 0.1 mm filaments. The required magnetic field of 100 mT will be excited by a permanent magnet. In the fast turn-by-turn mode the beam profile will be read out with a resolution of 1 mm by a 100-channel photodiode-amplifier-digitizer. The high resolution mode of 0.1 mm is provided by a CCD camera with upstream MCP-phosphor screen assembly. In this paper the first results of the photodiode-digitizer device testing, the compact mechanical design features and simulation results of the permanent magnet device are presented.  
 
THPLT140 Commissioning of BL 7.2, the New Diagnostic Beamline at the ALS diagnostics, electron, radiation, storage-ring 2783
 
  • F. Sannibale, D. Baum, A. Biocca, N. Kelez, T. Nishimura, T. Scarvie, E. Williams
    LBNL, Berkeley, California
  • K. Holldack
    BESSY GmbH, Berlin
  BL 7.2 is a new beamline at the Advanced Light Source (ALS) dedicated to electron beam diagnostics. The system, which is basically a hard x-ray pinhole camera, was installed on the storage ring in August 2003 and the commissioning with the ALS electron beam followed immediately after. In this paper, the commissioning results are presented together with the description of the relevant measurements performed for the beamline characterization.  
 
THPLT142 A Laser-Based Longitudinal Density Monitor for the Large Hadron Collider laser, synchrotron, monitoring, radiation 2789
 
  • S. De Santis, J.F. Beche, J.M. Byrd, P. Datte, M. Placidi, V. Riot, R.W. Schoenlein, W.C. Turner, M.S. Zolotorev
    LBNL, Berkeley, California
  We report on the development of an instrument for the measurement of the longitudinal beam profile in the Large Hadron Collider. The technique used, which has been successfully demonstrated at the Advanced Light Source, mixes the synchrotron radiation with the light from a mode-locked solid state laser oscillator in a non-linear crystal. The up-converted radiation is then detected with a photomultiplier and processed to extract, store and display the required information. A 40 MHz laser, phase-locked to the ring radiofrequency system, with a 50 ps pulse length, would be suitable for measuring the dynamics of the core of each of the LHC 2808 bunches in a time span much shorter then the synchrotron period. The same instrument could also monitor the evolution of the bunch tails, the presence of untrapped particles and their diffusion into nominally empty RF buckets ("ghost bunches") as required by the CERN specifications. We also specify the required characteristics of the diagnostic light port in the LHC where our instrument would be installed.

* Presently at Lawrence Livermore National Laboratory.

 
 
THPLT143 Development of an Abort Gap Monitor for the Large Hadron Collider synchrotron, synchrotron-radiation, radiation, diagnostics 2792
 
  • S. De Santis, J.F. Beche, J.M. Byrd, M. Placidi, W.C. Turner, M.S. Zolotorev
    LBNL, Berkeley, California
  The Large Hadron Collider, presently under construction at CERN, requires a monitor of the parasitic charge in the 3.3 ?s long gap in the machine fill structure, referred to as the abort gap, which corresponds to the raise time of the abort kickers. Any circulating particle present in the abort gap at the time of the kickers firing is lost inside the ring, rather than in the beam dump, and can potentially damage a number of the LHC components. CERN specifications indicate a linear density of 6x106 protons over a 100 ns interval as the maximum charge safely allowed in the abort gap at 7 TeV. We present a study of an abort gap monitor, based on a photomultiplier with a gated microchannel plate, which would allow for detecting such low charge densities by monitoring the synchrotron radiation emitted in the superconducting undulator dedicated to the measurement of the longitudinal beam properties. We show results of beam test experiments at the Advanced Light Source using an Hamamatsu 5916U MCP-PMT which indicate that such an instrument has the required sensitivity to meet LHC specifications.  
 
THPLT147 Beam Halo Monitoring on the CLIC Test Facility 3 electron, monitoring, linac, radiation 2801
 
  • T. Lefevre
    NU, Evanston
  • H.-H. Braun, E. Bravin, R. Corsini, A.-L. Perrot, D. Schulte
    CERN, Geneva
  In high intensity accelerators, the knowledge of the beam halo distribution and its generation mechanisms are important issues. In order to study these phenomena, dedicated beam diagnostics must be foreseen. In circular machines, beam halo was monitored by using scrapers and beam loss detectors. In the framework of the CLIC project, beam halo monitoring is currently under development. The proposed device is based on an imaging system and a masking technique, which suppresses the core of the beam to allow direct observation of the beam halo. A first test was performed on the CLIC test facility 3 in 2003. We discuss the performances and the limitations of this technique pointing out our plans for future developments.  
 
THPLT154 Design of an X-ray Imaging System for the Low-Energy Ring of PEP-II positron, dipole, vacuum, radiation 2819
 
  • A.S. Fisher, D. Arnett, H. De Staebler, S. Debarger, R.K. Jobe, D. Kharakh, D.J. McCormick, M. Petree, M.C. Ross, J. Seeman, B. Smith
    SLAC, Menlo Park, California
  • J. Albert, D. Hitlin
    CALTECH, Pasadena, California
  • J. Button-Shafer, J.A. Kadyk
    LBNL, Berkeley, California
  An x-ray beam-size monitor for positrons in the low-energy ring (LER) of the PEP-II B Factory at SLAC is being designed to accommodate the present 2-A, 3.1-GeV beam and anticipated currents of up to 4.7 A. The final photon stop of an arc will be rebuilt to pass dipole radiation through cooled apertures to optics 17 m from the source. Zone-plate imaging there can achieve a resolution of 6 microns, compared to 35 for a pinhole camera. Two multilayer x-ray mirrors precede the zone plate, limiting the bandwidth to 1%, in order to avoid chromatic blurring and protect the zone plate. Despite the narrow bandwidth, the zone plate?s larger diameter compared to a pinhole camera allows for a comparable photon flux. We will image all 1700 LER bunches and also measure them individually, searching for variations along the train due to electron-cloud and beam-beam effects, using a scanning detector conceptually derived from a wire scanner. A mask with three narrow slots at different orientations will scan the image to obtain three projections. In one passage, signals from a fast scintillator and photomultiplier will be rapidly digitized and sorted to profile each bunch.