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MOP21 The Pre-Injector Linac for the Diamond Light Source linac, diagnostics, electron, booster 84
 
  • C. Christou, V. Kempson
    DIAMOND, Chilton, Didcot, Oxon
  • K. Dunkel, C. Piel
    ACCEL, Bergisch Gladbach
  The Diamond Light Source is a new medium-energy high brightness synchrotron light facility which is under construction on the Rutherford Appleton Laboratory site in the U.K. The accelerator facility can be divided into three major components; a 3 GeV 561 m circumference storage ring, a full-energy booster synchrotron and a 100 MeV pre-injector linac. This paper describes the linac design and plans for operation. The linac is supplied by ACCEL Instruments GmbH under a turn-key contract, with Diamond Light Source Ltd. providing linac beam diagnostics, control system hardware and standard vacuum components. Commissioning of the linac will take place in early 2005 and user operation of the facility will commence in 2007.  
 
MOP26 ERLP Gun Commissioning Beamline Design electron, diagnostics, emittance, laser 93
 
  • D.J. Holder, C.K.M. Gerth, F.E. Hannon
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • R.J. Smith
    CLRC, Daresbury, Warrington, Cheshire
  The 4GLS project is a novel next-generation solution for a UK national light source. It is based on an energy recovery linac (ERL) operating at high average beam currents up to 100 mA and with compression schemes producing pulses in the 10 - 100 fs range. This challenging accelerator technology, new to Europe, necessitates a significant R&D programme and a major part of this is a low-energy prototype, the ERLP, which is currently under construction at Daresbury Laboratory, in the north-west of England. The first components of ERLP to be built will be the DC photocathode gun and low-energy beam transport and diagnostics. The gun will initially be operated with a diagnostic beamline in order to measure the properties of the high-brightness beams generated as fully as possible. This will allow comparison of its performance with the results of multi-particle tracking codes, prior to its integration into the ERLP machine. The diagnostic beamline will include diagnostics for measuring the transverse and longitudinal properties of the electron beam. This paper will describe the design of this diagnostic beamline and demonstrate through simulation, the expected characteristics and performance achievable from this system.  
 
MOP27 Commissioning of a 6 MeV X-Band SW Accelerating Guide electron, linac, vacuum, injection 96
 
  • Q. Jin, Y. Lin, X. Sun, X. Tao, D. Tong
    TSINGHUA, Beijing
  • B. Chen, B. Sun, Y. Zou
    BIEVT, Beijing 100016
  A 6 MeV, X-band on-axis SW electron linear accelerating guide is being developed in Accelerator laboratory of Tsinghua University. It can be suitable for portable radiation therapy and radiography. The design, manufacture and high power test of the guide are given in this paper. The guide is 38 cm long and contains 25 accelerating cells with 24 coupling cells, operated in the π/2 mode. The RF power source is a pulsed magnetron at 9300 MHz with 1.5 MW peak power. The results of beam tests are following: the electron energy is more than 6 MeV at 50 mA and focal spot size is less than φ 1.5 mm without any focusing solenoid.  
 
MOP29 RHIC Electron Cooler electron, cathode, emittance, linac 102
 
  • J. Kewisch, I. Ben-Zvi, R. Calaga, X.Y. Chang, A. Jain, V. Litvinenko, C. Montag, V. Yakimenko
    BNL, Upton, Long Island, New York
  Electron cooling has been applied in many accelerators with low energies where cooling times are short. Electron cooling is now considered for RHIC, where gold ions are stored at 100 GeV/u. For a cooling time of one hour an electron beam with 55 MeV and 10 nC/bunch is necessary. The transverse normalized emittance must be 50 mm·mrad, the energy spread 10-4. Only a Photo-cathode Energy Recovery LINAC (PERL) promises such quality. For a minimum electron temperature inside the 1 Tesla cooling solenoid it is necessary to have a "magnetized beam", i.e. a beam from a cathode immersed in a longitudinal magnetic field. The emittance compensation scheme used in RF guns was adapted so that the magnetization does not lead to strong emittance growth. A super-conducting cavity was developed for the RHIC electron cooler, optimized for high current operation. Simulations with the TBBU computer code show a multi-bunch beam breakup threshold of 3 Amperes. After acceleration the bunches are lengthened and the energy spread is reduced by rotation in the longitudinal phase space. The original bunch length must be restored by a second rotation before deceleration and energy recovery.  
 
MOP30 Linear Accelerator LINAC-800 of the DELSY Project electron, acceleration, linac, radiation 105
 
  • V.V. Kobets, N. Balalykin, I.N. Meshkov, I.A. Seleznev, G. Shirkov
    JINR, Dubna, Moscow Region
  In the report the modernization of electron linear accelerator MEA (Medium Energy Accelerator) is discussed. The goal of the work is to create on the base of MEA a complex of free electron lasers overlaying a range of radiation waves from infrared to ultraviolet. Status of the work is reported.  
 
MOP34 Injector Linac Upgrade for the BEPCII Project positron, electron, linac, target 111
 
  • S.H. Wang
    IHEP Beijing, Beijing
  BEPCII- an upgrade project of Beijing Electron Positron Collider (BEPC) is a factory type of e+e- collider. It requests its injector linac to have the higher beam energy (1.89 GeV) for on-energy injection and the higher beam current (40 mA e+ beam) for higher injection rate (≥50 mA/min). The low beam emittance (1.6 π·mm·mrad for e+ beam, and 0.2 π·mm·mrad for 300 mA e- beam) and low beam energy spread (±0.5%) are also requested to meet the storage ring acceptance. Hence the original BEPC injector linac must be upgraded to have a new electron gun with its complete tuning system, a new positron source with a flux concentrator, a new RF power system with its phasing loops and a new beam tuning system with orbit correction and optics tuning devices. These new components have been designed, fabricated, tested and now being installed in their final positions, which are described in this paper. The beam commissioning is expected to start from the October of 2004.  
Transparencies
 
MOP36 Preliminary Study on HOM-Based Beam Alignment in the TESLA Test Facility polarization, dipole, alignment, higher-order-mode 117
 
  • N. Baboi, G. Kreps, M. Wendt
    DESY, Hamburg
  • G. Devanz, R. Paparella
    CEA/DAPNIA-SACM, Gif-sur-Yvette Cedex
  • O. Napoly
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  The interaction of the beam with the higher order modes (HOM) in the TESLA cavities has been studied in the past at the TESLA Test Facility (TTF) in order to determine whether the modes with the highest loss factor are sufficiently damped. The same modes can be used actively for beam alignment. At TTF the beam alignment based on the HOM signals is planned to be studied in the first cryo-module, containing 8 accelerating cavities. One of several modes with higher loss factor will be used. Its polarization has to be determined. The options to use single bunches or bunch trains will be analyzed. The results will be discussed in this paper.  
 
MOP47 Limiting Effects in the Round-To-Flat Beam Transformation emittance, simulation, quadrupole, chromatic-effects 150
 
  • Y.-E. Sun, K.-J. Kim
    Chicago University, Chicago, Illinois
  • P. Piot
    FNAL, Batavia, Illinois
  The transformation of an angular-momentum-dominated beam into a flat beam was analyzed in Ref. [K.-J. Kim, Phys. rev. ST A&B, vol 6, 104002 (2003)]. The analysis was performed assuming that the beam and the transport channel upstream of the flat beam transformer are cylindrically symmetric and that the particle dynamics is symplectic. We extend the analysis to include chromatic and space-charge effects as well as asymmetries in the four dimensional transverse phase space distribution.  
 
MOP76 Ultra-High-Vacuum Problem for 200 keV Polarized Electron Gun with NEA-GaAs Photocathode emittance, electron, ion, cathode 201
 
  • T. Nakanishi, F. Furuta, M. Kuwahara, K. Naniwa, S. Okumi, M. Yamamoto, N. Yamamoto, K. Yasui
    DOP Nagoya, Nagoya
  • H. Kobayakawa, Y. Takashima
    DOE Nagoya, Nagoya-City
  • M. Kuriki, H. Matsumoto, M. Yoshioka
    KEK, Ibaraki
  For a polarized electron source based on photoemission from GaAs, a NEA (Negative Electron Affinity) surface makes an indispensable role to extract polarized electrons in conduction band into vacuum. The NEA surface is also considered as a best surface to provide a beam with a minimum initial beam-emittance. However, the NEA surface state is realized by a mono-layer of electric dipole moment (that is Ga(-)-Cs(+)) formed at the surface and thus it is easily degraded by
  1. desorption of harmful residual gas,
  2. desorption of harmful gas created by field emission from HV-cathodes and
  3. ion back-bombardment.
In order to reduce the effects of (a) and (c), extremely good UHV is required. Presently total pressure of 4·10-12 torr and respective partial pressures of 3·10-13 torr and 4·10-13 torr for H2O and CO2 were achieved at our gun chamber. Field emission dark current must be extremely suppressed to reduce the effect of (c). The maximum field gradient of 7.8 MV/m is applied for electrode envelope (3.0 MV/m for cathode surface) at 200 kV DC bias-voltage, but total dark current was suppressed below 1 nA for our electrodes. The NEA lifetime under these conditions will be reported at the conference.
 
 
MOP77 Design Parameters of the Normal Conducting Booster Cavity for the PITZ-2 Test Stand vacuum, coupling, booster, emittance 204
 
  • V.V. Paramonov, N.I. Brusova, A.I. Kvasha, A. Menshov, O.D. Pronin, A.K. Skasyrskaya, A.A. Stepanov
    RAS/INR, Moscow
  • A. Donat, M. Krasilnikov, A. Oppelt, F. Stephan
    DESY Zeuthen, Zeuthen
  • K. Flöttmann
    DESY, Hamburg
  The normal conducting booster cavity is intended to increase the electron bunch energy in the Photo Injector Test (DESY, Zeuthen) stage 2 experiments. The normal conducting cavity is selected due to infrastructure particularities. The L-band cavity is designed to provide the accelerating gradient up to 14 MV/m with the total input RF power 8.6 MW, RF pulse length up to 900 mks and repetition rate 5 Hz. The multi-cell cavity is based on the CDS compensated accelerating structure with the improved coupling coefficient value. The main design ideas and decisions are described briefly together with cavity parameters - RF properties, cooling and pumping circuits.  
 
MOP80 Development of Adaptive Feedback Control System of Both Spatial and Temporal Beam Shaping for UV-Laser Light Source for RF Gun laser, electron, emittance, cathode 207
 
  • H. Tomizawa, T. Asaka, H. Dewa, H. Hanaki, T. Kobayashi, A. Mizuno, S. Suzuki, T.  Taniuchi, K. Yanagida
    JASRI-SPring-8, Hyogo
  • F. Matsui
    FKLAB, Fukui City
  The ideal spatial and temporal profiles of a shot-by-shot single laser pulse are essential to suppress the emittance growth of the electron beam from a photo-cathode rf gun. We have been developing highly qualified UV-laser pulse as a light source of the rf gun for an injector candidate of future light sources. The gun cavity is a single-cell pillbox, and the copper inner wall is used as a photo cathode. The electron beam was accelerated up to 4.1 MeV at the maximum electric field on the cathode surface of 175 MV/m. For emittance compensation, two solenoid coils were used. As the first test run, with a microlens array as a simple spatial shaper, we obtained a minimum emittance value of 2 π·mm·mrad with a beam energy of 3.1 MeV, holding its charge to 0.1 nC/bunch. In the next test run, we prepared a deformable mirror for spatial shaping, and a spatial light modulator based on fused-silica plates for temporal shaping. We applied the both adaptive optics to automatically shape the both spatial and temporal UV-laser profiles with a feedback routine at the same time. We report herein the principle and developing process of our laser beam quality control system.  
 
TU202 Low Emittance 500 kV Thermionic Electron Gun cathode, emittance, electron, space-charge 261
 
  • K. Togawa, H. Baba, T. Inagaki, K. Onoe, T. Shintake, T. Tanaka
    RIKEN Spring-8 Harima, Hyogo
  • H. Matsumoto
    KEK, Ibaraki
  A 500 kV pulsed electron gun has been constructed for the injector system of the SASE-FEL project at SPring-8 (SCSS project). A CeB6 single crystal was chosen as a thermionic cathode, because of its excellent emission properties. We have succeeded in generating a 500 keV beam with 1 A peak current and 3 μs FWHM. The beam was very stable with low jitter. The beam emittance has been measured by means of double-slits method, and the normalized rms emittance of 1.1 π·mm·mrad has been obtained. We report on the experimental result on the emittance measurement of the CeB6 electron gun.  
Transparencies
 
TUP43 The Superconducting CW Driver Linac for the BESSY-FEL User Facility linac, emittance, simulation, beam-loading 363
 
  • J. Knobloch
    BESSY GmbH, Berlin
  A CW FEL User Facility for the VUV to soft X-ray spectral range based on a cascaded HGHG-FEL scheme is planned at the BESSY site. The Technical Design Report has recently been submitted to the German Wissenschaftsrat. Beam acceleration to 2.3 GeV is provided by a 144-cavity superconducting driver linac based on TESLA technology modified for CW operation. Initially, a high-rep-rate normal-conducting photoinjector will be used but a fully CW superconducting version is being investigated for a future upgrade. Bunch compression to 2 kA peak current is achieved in a three-stage scheme involving two bunch compressors and an arc. An overview of the linac layout, including the rf and cryogenic distribution, is provided here. We also discuss the impact of CW operation and the modifications to the TESLA technology that are necessary. Predictions of the linac performance are also given.  
Transparencies
 
TUP44 Linac Upgrades for FERMI@ELETTRA linac, klystron, injection, laser 366
 
  • G. D'Auria, R.J. Bakker, P. Craievich, G. De Ninno, S.D. Di Mitri, M. Ferianis, P.G. Pangon, R.L. Rumiz, T.L. Tosi, D. Zangrando
    Sincrotrone Trieste S.C.p.A., Basovizza, Trieste
  • C. Bocchetta, M. Danailov, B. Diviacco, V. Verzilov
    ELETTRA, Basovizza, Trieste
  To fulfill the stringent requirements expected from the FERMI project, the existing Linac needs some modifications in the layout and an upgrading of the present plants. Moreover, for the next two years, until the new injection system (now under construction) is fully commissioned, the Linac has to be kept in operation as injector for the ELETTRA Storage Ring. Therefore most of the planned activities have to be carried out without interfering with the normal operation of the machine. Details on the new Linac layout and related activities are discussed.  
 
TUP45 Extended Parametric Evaluation for 1 Å FEL - Emittance and Current Requirements emittance, undulator, electron, radiation 369
 
  • M. Pedrozzi, G. Ingold
    PSI, Villigen
  In the synchrotron radiation community there is a strong request for high brightness, coherent X-ray light pulses, especially in the 1 to 0.1 nm wave length range. A Free Electron Laser (FEL), driven by a linear single pass accelerator, is today the most promising mechanism able to produce such radiation. Since the electron beam brightness plays a major role in the laser saturation process and in the final energy of the driving linac, many laboratories are presently working on a new generation of low emittances sources. The present analysis will give an indication about the FEL behaviour and the undulator parameters versus the slice beam quality (emittance, current, energy spread).  
 
TUP47 The Photo Injector Test Facility at DESY Zeuthen: Results of the First Phase emittance, laser, cathode, electron 375
 
  • A. Oppelt, K. Abrahamyan, I. Bohnet, J. Bähr, U. Gensch, H.-J. Grabosch, J.H. Han, M. Krasilnikov, D. Lipka, V. Miltchev, B. Petrosyan, L. Staykov, F. Stephan
    DESY Zeuthen, Zeuthen
  • W. Ackermann, W.F.O. Müller, S. Setzer, T. Weiland
    TU Darmstadt, Darmstadt
  • J.-P. Carneiro, K. Flöttmann, S. Schreiber
    DESY, Hamburg
  • E. Jaeschke, D. Krämer, D. Richter, M. von Hartrott
    BESSY GmbH, Berlin
  • P. Michelato, C. Pagani, D. Sertore
    INFN/LASA, Segrate (MI)
  • J. Rossbach
    Uni HH, Hamburg
  • W. Sandner, I. Will
    MBI, Berlin
  • I. Tsakov
    INRNE, Sofia
  The photo injector test facility at DESY Zeuthen successfully concluded it's first phase of operation in November 2003 (PITZ1). After a complete characterization of the injector, the gun has been delivered to Hamburg and has already been taken into operation on the VUV-FEL. The measurement program for the year 2003 included RF commissioning, emittance studies, momentum and bunch length measurements, and studies of the influence of the drive laser parameters. We provide an overview on the latest achievements in all of these topics.  
Transparencies
 
TUP58 Alternative Linac Layout for European XFEL Project linac, emittance, space-charge, simulation 399
 
  • Y. Kim, K. Flöttmann, T. Limberg
    DESY, Hamburg
  • Y. Kim, D. Son
    CHEP Korea, Daegu
  To satisfy required beam parameters and to increase the jitter tolerance, we have designed an alternative linac layout with two bunch compressor stages for the European XFEL project. In this paper, we describe start-to-end (S2E) simulation of the alternative linac layout for the European XFEL project, and compare its results with our current linac layout with one bunch compressor stage.  
 
TUP59 Extraction of High Charge Electron Bunch from the ELSA RF Injector - Comparison Between Simulation and Experiment simulation, space-charge, laser, electron 402
 
  • J. Lemaire, P. Balleyguier, A. Binet, J.M. Lagniel, V. Le Flanchec, N. Pichoff
    CEA/DAM, Bruyères-le-Châtel
  • R. Bailly-Salins, M. Millerioux, Chr. Quine
    CEA/DIF/DPTA/SP2A, Bruyeres-le-Chatel
  A new scheme based on a photoinjector and a RF linear accelerator operating at 352 MHz has been recently proposed as a versatile radiographic facility. Beam pulses of 60 ns duration contain 20 succesive electron bunches which will be extracted at 2.5 MeV from a photoinjector then accelerated through the next structure to the final energy of 51 MeV. Bunches carrying 100 nC are required for this purpose. As a first demonstrating step, 50 nC electron bunches have been produced and accelerated to 2.5 MeV with the 144 MHz ELSA photoinjector at Bruyères le Chatel. For this experiment, we compare the results and the numerical simulations made with PARMELA, MAGIC and MAFIA codes.  
 
TUP94 Parallel Particle in Cell Computation of an Electron Gun with GdfidL electromagnetic-fields, acceleration, scattering, electron 498
 
  • W. Bruns
    TU Berlin TET, Berlin
  The paper describes an efficient algorithm to integrate the equations of a fast moving charge cloud of small size in a large electron gun. Particle in cell computations of a realistic electron gun is challenging due to the large discrepancy between the size of the cavity and the size of the cloud. A fine grid must be used to resolve the small volume of the charge, with a grid spacing in the order of 0.1 mm. The cavity has extensions of about 100 mm. Therefore one has to deal with about 1000 million gridcells. Such a large grid is handled best with parallel systems. Each node of the parallel system computes the electromagnetic field in its subvolume. As the extension of the charge keeps being small during the flight, at each timestep the charged particles will be located in only a few subvolumes of the nodes of the parallel system. This would lead to a strong load imbalance, if the particle related computations for each particle would be performed by the node where the particle is in. GdfidL instead spreads the data of all particle over all processors, which perform the particle related computations, and send back the results to the processors where the particles are in.  
 
TH201 IOT RF Power Sources for Pulsed and CW Linacs klystron, linac, electron, simulation 574
 
  • H.P. Bohlen
    CPI, Palo Alto, California
  • Y. Li, R.N. Tornoe
    CPI/EIMAC, San Carlos, California
  For many years, klystrons have been the preferred RF power amplifiers for both pulsed and CW linacs at UHF and higher frequencies. Their properties have earned them that position. But in recent years in UHF terrestrial television transmitters the earlier predominant klystron has been replaced the Inductive Output Tube (IOT) because the IOT provides higher efficiency and, due to its excellent linearity, can handle the simultaneous amplification of both the vision and the sound signal. Its robustness and life expectancy equals that of a klystron, and it more than compensates its lower gain by a lower price and a smaller size. For linac operation, derivates of UHF TV IOTs, capable of up to 80 kW CW output power, are already available and operating. In L-Band, they are presently joined by recently developed 15 to 30 kW CW IOTs. HOM-IOTs are expected to extend the CW range in UHF to 1 MW and beyond. Pulsed operation of an IOT can be achieved without a high-voltage modulator. Since the beam current is grid-controlled it is sufficient to pulse the drive power.  
Transparencies
 
THP25 Development of Field-Emission Electron Gun from Carbon Nanotubes cathode, electron, acceleration, vacuum 651
 
  • Y. Hozumi
    GUAS/AS, Ibaraki
  • M. Ikeda, S. Ohsawa, T. Sugimura
    KEK, Ibaraki
  Aiming to use a narrow energy-spread electron beam easily and low costly on injector electron guns, we have been tested field emission cathodes of carbon nanotubes (CNTs). Experiments for these three years brought us important suggestions and a few rules of thumb. Now at last, anode current of 3.0 [A/cm2] was achieved with 8 kV acceleration voltage by applying short grid pulses between cathode-grid electrodes. In order to proof utility, 100 kV gun system had been designed and structured since last year. Then the value of 300 mA was obtained based on 10-5…10-6 [Pa] back ground pressures. With some improvements anode currents of Ampere order is expected.  
 
THP27 Ultra Low Emittance Electron Gun Project for FEL Application emittance, cathode, electron, simulation 657
 
  • R. Ganter, M. Dehler, J. Gobrecht, C. Gough, G. Ingold, S. Leemann, M. Paraliev, M. Pedrozzi, J.-Y. Raguin, L. Rivkin, V. Schlott, A. Streun, A. Wrulich
    PSI, Villigen
  • A. Candel, K. Li
    ETH, Zürich
  Most of the current 1Å Free-Electron Laser (FEL) projects are based on thermionic or photocathode guns aiming at an electron beam emittance of 0.5 to 1 mm·mrad. The design of a gun capable of producing a beam with an emittance one or two order of magnitude lower than the state of the art would reduce considerably the cost and size of such a FEL. Due to the recent advances in nanotechnologies and vacuum microelectronics, a field-emitter based gun is a promising alternative scheme. We present first measurements on commercial field emitter arrays as well as 3-D numerical simulations of the electron beam dynamics for typical bunch distributions generated from field emitters in realistic gun geometries. The design and some experimental results on a 500kV pulser is also presented.  
Transparencies
 
THP45 The Toshiba E3736 Multi Beam Klystron klystron, electron, cathode, simulation 706
 
  • A. Yano, S. Miyake
    TETD, Saitama
  • Y.H. Chin
    KEK, Ibaraki
  • S.Y. Kazakov
    IHEP Protvino, Protvino, Moscow Region
  • A.V. Larionov, V.E. Teryaev
    BINP SB RAS, Protvino, Moscow Region
  A 10 MW, L-band multi beam klystron (MBK) for TESLA linear collider and TESLA XFEL has been under development at Toshiba Electron Tubes & Devices Co., Ltd. (TETD) in collaboration with KEK. The TESLA requires pulsed klystrons capable of 10 MW output power at 1300 MHz with 1.5 ms pulse length and a repetition rate of 10 pps. The MBK with 6 low-perveance beams in parallel in the klystron enables us to operate at lower cathode voltage with higher efficiency. The design work has been accomplished and the fabrication is under way. We are going to start conditioning and testing of prototype #0 in the beginning of June 2004. The design overview and the initial test results at the factory will be presented.  
 
FR104 Overview on High-Brightness Electron Guns electron, emittance, brightness, cathode 842
 
  • J.W. Lewellen
    ANL, Argonne, Illinois
  In an electron storage ring, the quality of the electron beam is generally a function of the ring lattice parameters and has little to do with the source of the electrons. In most electron linear accelerators, the beam brightness is set by the beam source. It is very difficult to improve the overall beam brightness after it has been produced; on the other hand, providing a brighter beam source can provide an “instant upgrade” to the performance of a brightness-limited electron linac-based facility. The development and routine operation of high-brightness guns, therefore, is critical to the success of next-generation linac-based light sources. This includes sources already under construction, such as LCLS, as well as proposed and as-yet completely theoretical machines. In this talk I present a general overview of the state-of-the-art in high-brightness electron beam source development, discuss the concept of “situational brightness”, and highlight some interesting paths towards future devices. I conclude with thoughts on some possible alternate applications for high-brightness beams.  
Transparencies