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MOYCH03 Superconducting RF Cavities for Synchrotron Light Sources damping, synchrotron, extraction, hadron 21
 
  • P. Marchand
    SOLEIL, Gif-sur-Yvette
  Superconducting (sc) RF systems are already operational or planned in several third generation synchrotron light sources. In these machines, which require relatively low RF accelerating voltage and high beam loading, the advantage of using the sc technology essentially resides in the fact that one can achieve an efficient damping of the cavity Higher Order Modes (HOM) while still maintaining a high fundamental shunt impedance. The strong HOM damping practically is realised following two approaches : a) use of absorber material, located inside the cavity tube cut-off, through which the HOM propagate and then are damped (Cornell/KEK designs); b) two-cell cavity with coaxial HOM dampers located on the tube connecting the two cells (SOLEIL design). Third harmonic idle sc cavities (1.5 GHz) of the SOLEIL type are already operational in the Swiss Light Source and ELETTRA. The main RF system (500 MHz) of these machines consist of normal conducting cavities and the purpose of the third harmonic sc system is to lengthen the bunches in order to improve the beam lifetime and stability (additional Landau damping). Recently, several third generation synchrotron light sources have also planned to use sc cavities as main accelerating RF systems. The operational conditions of the existing systems as well as the status of the planned ones are reported here.  
Video of talk
Transparencies
 
MOZCH01 Technologies for Electron-positron Linear Colliders damping, collider, synchrotron, extraction 26
 
  • S.D. Holmes
    Fermilab, Batavia, Illinois
  High energy electron-positron Linear Collider designs based on room temperature and superconducting technologies have been developed and are currently under consideration by the International Technology Recommendation Panel. This paper will review the requirements and state of development of technologies required to support a linear collider meeting the performance goals outlined by the world high energy physics community. In addition it will summarize the cold/warm comparative study completed in the U.S. with particular emphasis on unique aspects related to availability and risk analysis.  
Video of talk
Transparencies
 
TUPKF034 Low Output-Impedance RF System for 2nd Harmonic Cavity in the ISIS Synchrotron positron, focusing, plasma, booster 1036
 
  • T. Oki, S. Fukumoto, Y. Irie, M. Muto, S. Takano, I. Yamane
    KEK, Ibaraki
  • R.G. Bendall, I.S.K. Gardner, M.G. Glover, J. Hirst, D. Jenkins, A. Morris, S. Stoneham, J.W.G. Thomason, T. Western
    CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
  • J.C. Dooling, D. Horan, R. Kustom, M.E. Middendorf, G. Pile
    ANL, Argonne, Illinois
  In the ISIS facility based at Rutherford Appleton Laboratory (RAL) in the UK, second target station project was funded, which requires to increase the current intensity by 1.5-times (300 micro-A). Four 2nd harmonic RF cavities will be installed in the ISIS synchrotron in order to increase the trapping efficiency, and to mitigate the space charge detuning. A very low output-impedance RF system for the 2nd harmonic cavity has been developed by the collaboration between RAL, Argonne National Laboratory (US) and KEK (Japan). The system comprises the 240 kW triode as a final amplifier with plate-to-grid feedback path. The measured output-impedance was less than 30 ohms over the frequency range of 2.7 - 6.2 MHz, which agreed well with calculations. High power test was also performed under frequency swept mode at 50 Hz repetition. The operation was almost stable, and more than 12 kVpp was obtained as maximum. The voltage gain of the final amplifier was 25 - 30, which decreased gradually with frequency due to decreasing input-impedance of triode. The beam test is planned at ISIS in near future.  
 
TUPKF035 RF System for Compact Medical Proton Synchrotron positron, focusing, plasma, acceleration 1039
 
  • Z. Fang, K. Egawa, K. Endo, S. Yamanaka
    KEK, Ibaraki
  • Y. Cho, T. Fusato, T. Hirashima
    DKK, Kanagawa
  The rf system has been developed for the compact medical proton synchrotron. The rf system will be operated in pulse mode with the fundamental rf frequency sweeping from 1.6 to 15 MHz during the acceleration time of 5 ms. The required rf cavity voltage is a function of acceleration time too, with the voltage of fundamental varying from 13 to 6 kV. Besides, high order harmonics are also considered to apply to the rf system, and the cavity peak voltage varying from 20 to 9 kV during the acceleration time is expected. The performance of the rf system is being studied and will be presented.  
 
TUPKF036 RF Property of the Prototype Cryomodule for ADS Superconducting Linac positron, focusing, plasma, acceleration 1042
 
  • E. Kako, S. Noguchi, N. Ohuchi, T. Shishido
    KEK, Ibaraki
  • N. Akaoka, H. Kobayashi, N. Ouchi, T. Ueno
    JAERI/LINAC, Ibaraki-ken
  • H. Hara, M. Matsuoka, K. Sennyu
    MHI, Kobe
  A prototype cryomodule containing two 9-cell superconducting cavities of beta=0.725 and frequency=972MHz is being constructed under the collaboration of Japan Atomic Energy Research Institute (JAERI) and High Energy Accelerator Research Organization (KEK) on the development of superconducting LINAC for Accelerator Driven System (ADS). Design and performance of RF components will be reported.  
 
TUPKF037 Multi-harmonic RF Acceleration System for a Medical Proton Synchrotron positron, focusing, plasma, booster 1045
 
  • K. Saito, M. Katane, K. Kobayashi, K. Masui, K. Moriyama, H. Nishiuchi, H. Sakurabata, H. Satomi
    Hitachi, Ltd., Power & Industrial Systems R&D Laboratory, Ibaraki-ken
  We have developed an RF accelerating system for medical proton synchrotron. The RF cavity is a tuning-free wideband type, loaded with FINEMET cores, which is driven by a solid-state RF power amplifier with operation frequency range between 1MHz and 10MHz. Multi-harmonic RF acceleration scheme has been realized with the RF control system, to reduce beam loss by space-charge effect in low energy region. The original techniques for high-speed digital signal processing and high-precision RF signal processing have been applied, in order to fulfill feedback control of the frequency, phase and amplitude of the second and third harmonic RF signals as well as the fundamental one.  
 
TUPKF038 Reduced Length Designs of 500 MHz Damped Cavity Using SiC Microwave Absorber positron, focusing, plasma, booster 1048
 
  • T. Koseki
    RIKEN/RARF/BPEL, Saitama
  • M. Izawa, S. Sakanaka, T. Takahashi, K. Umemori
    KEK, Ibaraki
  We present a new 500 MHz HOM (Higher-Order Modes) damped cavity for high brilliance synchrotron radiation sources. The design is based on the damped cavity, which is operated at the Photon Factory storage ring in KEK. The PF cavity has a large hole beam duct (140 mm in diameter), a part of which is made of a silicon carbide (SiC) microwave absorber. The new cavity, proposed in this paper, has parallel-plate radial transmission lines on the beam duct instead of the SiC beam duct. The outer end of the radial line is terminated by SiC absorbers. The HOMs, extracted from the center part of the cavity through the beam duct, propagate in the radial line and are dissipated in the absorber. The accelerating mode is not affected by the radial line damper since the frequency is sufficiently below the cutoff of the 140-mm beam duct. In this paper, optimized design of the radial line damper and damping properties for HOMs are described in detail.  
 
TUPKF039 The Experiences of Operation and Performance about the 500 MHz CW Klystrons at the PLS Storage Ring positron, focusing, plasma, booster 1051
 
  • J.S. Yang, M.-H. Chun, Y.J. Han, S.-H. Nam, I.H. Yu
    PAL, Pohang
  There are four RF stations to supply the energy to electron at the storage ring of the Pohang Light Source(PLS). From the beginning of the operation of RF system, 500MHz 60kW(CW) klystrons have been operated. As the operation time of the tubes are increased, their performances are decreased. Therefore three 60kW tubes were replaced with the same model and two 75kW klystrons were replaced with 60 kW klystrons so far. Nowadays two 75 kW and two 60 kW klystrons are operated in the RF system of PLS. Our experiences of the klystron operation and their general performance are described in this paper.  
 
TUPKF041 Quasi-optic RF Power Transmission Line from a FEM Oscillator to the Model of the CLIC Accelerating Structure positron, focusing, plasma, booster 1054
 
  • A. Kaminsky, A.V. Elzhov, E.A. Perelstein, N.V. Pilyar, T.V. Rukoyatkina, S. Sedykh, A.P. Sergeev, A. Sidorov
    JINR, Dubna, Moscow Region
  • N.S. Ginzburg, S.V. Kuzikov, N.Yu. Peskov, M.I. Petelin, A. Sergeev, N.I. Zaitsev
    IAP/RAS, Nizhny Novgorod
  Experimental investigation of a copper resonator lifetime under multiple action of 30 GHz power pulses is now carried out by the collaboration of CLIC team (CERN), FEM group of JINR (Dubna) and IAP RAS (Nizhny Novgorod). A quasi-optic two-mirror transmission line is used between the FEM oscillator and test cavity. An oversized FEM output waveguide based on the wavebeam transformation (Talbot effect) provides the optimal transverse distribution of the radiation, eliminates the output window breakdown and decrease the influence of the reflected wave on the FEM oscillator regime.  
 
TUPKF048 Studies of Electron Multipacting in CESR Type Rectangular Waveguide Couplers positron, focusing, plasma, booster 1057
 
  • P. Goudket, M. Dykes
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • S.A. Belomestnykh, R. Geng
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • R.G. Carter
    Microwave Research Group, Lancaster University, Lancaster
  • H. Padamsee
    Cornell University, Ithaca, New York
  The latest results from an experimental waveguide section, as well as simulations from a model of electron multipacting using the MAGIC PIC code, are discussed. Tests were carried out on a new waveguide section that included enhanced diagnostics and the possibility of changing surface materials and temperature. Those tests evaluated grooves, ridges and surface coatings, such as TiN and a TiZrV NEG coating, as methods of multipactor suppression. The conclusion remains that the most effective method to achieve complete multipactor suppression remains the application of a static magnetic bias of approximately 10G. The experiments also provided good data sets that can be used to verify the accuracy of simulations. Simulations of the waveguide multipacting have been carried out and have offered better understanding of electronic behaviour.  
 
TUPKF049 Combining Cavity for RF Power Sources: Computer Simulation and Low Power Model positron, focusing, plasma, booster 1060
 
  • E. Wooldridge, S.C. Appleton, B. Todd
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  A combining cavity for RF power sources has been investigated as a way of saving space, in comparison to waveguides, and as a way of combining power with graceful degradation if one or more component were to fail. The cavity has been investigated as the maximum power output of an Inductive Output Tube (IOT) for CW is 80KW at 500MHz and a proposed output of 20KW at 1.3GHz and most RF systems for particle accelerators require much more than this. Although 1.3GHz klystrons do exist they are vastly more expensive to purchase and maintain. Also the down time could be minimised to minutes in the even of a single IOT failure where as a klystron has a minimum downtime of several days in the event of a failure. Initially the cavity and its inputs were simulated in CSTs? Microwave studio. After optimising the cavity to ensure the minimum reflection at the input ports and maximum transmission at the output port, a low power model was then created from aluminium. Signal generators were used to power the model and a network analyser was used to check the output. The model was used to compare the results gained from the computer simulation and to obtain results from asymmetric positioning of the ports, which was not possible in the simulation.  
 
TUPKF050 Triggers for RF Breakdown positron, focusing, plasma, booster 1063
 
  • J. Norem, Z. Insepov
    ANL, Argonne, Illinois
  We outline a model of breakdown in rf cavities. Breakdown can be triggered by two mechanisms, one is fracture of the surface due to the tensile stress produced by the electric field, the second is Ohmic heating at grain boundaries and defects at very high current densities. We show how this model follows from measurements of local electric fields using electron field emission, and show how the model applies to the operating conditions of a variety of rf structures. This model may have some relevance to SCRF and DC structures.  
 
TUPKF053 New Waveguide-type HOM Damper for the ALS Storage Ring RF Cavities positron, focusing, plasma, cathode 1069
 
  • S. Kwiatkowski, K.M. Baptiste, J. Julian
    LBNL/ALS, Berkeley, California
  The ALS storage ring 500 MHz RF system uses two re-entrant accelerating cavities powered by a single 320kW PHILLIPS YK1305 klystron. During several years of initial operation, the RF cavities were not equipped with effective passive HOM damper systems. Longitudinal beam stability was achieved through cavity temperature control and the longitudinal feedback system (LFB), which was often operating at the edge of its capabilities. As a result, longitudinal beam stability was a significant operations issue at the ALS. During two consecutive shutdown periods (April 2002 and 2003) we installed E-type HOM dampers on the main and third harmonic cavities. These devices dramatically decreased the Q-values of the longitudinal anti-symmetric HOM modes. The next step is to damp the rest of the longitudinal HOM modes in the main cavities below the synchrotron radiation damping level. This will hopefully eliminate the need for the LFB and set the stage for a possible increase in beam current. The ?waveguide? type of HOM damper was the only option that didn?t significantly compromise the vacuum performance of the RF cavity. The design process and the results of the low level measurements of the new waveguide dampers are presented in this paper.  
 
TUPKF055 Space-charge-limited Magnetron Injection Guns for Gyroklystrons positron, focusing, plasma, booster 1072
 
  • W. Lawson
    Maryland University, College Park, Maryland
  We present the results of several space-charge-limited (SCL) magnetron injection gun (MIG) designs which are intended for use with a 500 kV, 500 A gyroklystron with accelerator applications. The design performances are compared to that of a temperature-limited (TL) gun that was constructed for the same application. The SCL designs yield similar values for beam quality, namely an axial velocity spread under 3% for an average perpendicular-to-parallel velocity ratio of 1.5. The peak electric fields and the cathode loadings of the SCL designs are somewhat higher than for the TL design. Three designs are described in this paper. In the first design the space-charge limit is achieved by recessing the emitter into the cathode. The other two designs have control electrodes to which a voltage can be applied to change the beam current independently of the beam voltage. One of these designs can accept a bias sufficiently high to cut off the current completely, so that a DC power supply with pulsed grid operation is possible. Details of all designs as well as a discussion of the advantages and disadvantages of the SCL designs as compared to the TL design will be given.  
 
TUPKF056 Multipacting in Crossed RF Fields near Cavity Equator positron, focusing, plasma, booster 1075
 
  • V.D. Shemelin
    Cornell University, Ithaca, New York
  Electric and magnetic fields near the cavity equator are presented in a form of expansions up to the third power of coordinates. Comparisons with numerical calculations made with the SLANS code for the TESLA and other cavity cells, as well as with the analytical solution for a spherical cavity are done. These fields are used for solution of equations of motion. It appears that for description of motion, the only main terms of the expansion are essential, but the value of coefficients for the electric field components depend on details of magnetic field behavior on the boundary. Equations of motion are solved for electrons moving in crossed RF fields near the cavity equator. Based on the analysis of these equations, general features of this kind of multipacting are obtained. Results are compared with simulations and experimental data. The "experimental" formulas for multipacting zones are explained and their dependence on the cavity geometries is shown. Developed approach allows evaluation of multipacting in a cavity without simulations but after an analysis of fields in the equatorial region. The fields can be computed by any code used for cavity calculation.  
 
TUPKF058 Test Results for the New 201.25 MHz Tetrode Power Amplifier at LANSCE positron, focusing, plasma, booster 1078
 
  • J.T.M. Lyles, S. Archuletta, J. Davis, L. Lopez, G. Roybal
    LANL/LANSCE, Los Alamos, New Mexico
  A new RF amplifier has been constructed for use as the intermediate power amplifier stage for the 201.25 MHz Alvarez DTL at LANSCE. It is part of a larger upgrade to replace the entire RF plant with a new generation of components. The new RF power system under development will enable increased peak power with higher duty factor. The first tank requires up to 400 kW of RF power. This can be satisfied using the TH781 tetrode in a THALES cavity amplifier. The same stage will be also used to drive a TH628 Diacrode? final power amplifier for each of the three remaining DTL tanks. In this application, it will only be required to deliver approximately 150 kW of peak power. Details of the system design, layout for DTL 1, and test results will be presented.  
 
TUPKF059 Simulation of Dark Currents in X-band Accelerator Structures positron, focusing, plasma, booster 1081
 
  • K.L.F. Bane, V.A. Dolgashev, G.V. Stupakov
    SLAC, Menlo Park, California
  In high gradient accelerator structures, such as those used in the main linac of the GLC/NLC, electrons are emitted spontaneously from the structure walls and then move under the influence of the rf fields. In this report we study the behavior of this "dark current" in X-band accelerator structures using a simple particle tracking program and also the particle-in-cell program MAGIC. We address questions such as what is the sensitivity to emission parameters, what fraction of dark current is trapped and reaches to the end of a structure, and what are the temporal, spatial, and spectral distributions of dark current as functions of accelerating gradient.  
 
TUPKF061 The SPEAR3 RF System positron, focusing, plasma, booster 1084
 
  • P.A. McIntosh, S. Allison, P. Bellomo, S. Hill, V. Pacak, S. Park, J.J. Sebek, D.W. Sprehn
    SLAC, Menlo Park, California
  SPEAR2 was upgraded in 2003, to a new 3rd Generation Light Source (3GLS) enabling users to take better advantage of almost 100x higher brightness and flux density over its predecessor SPEAR2. As part of the upgrade, the SPEAR2 RF system has been re-vamped from its original configuration of one 200 kW klystron feeding a single 358.5 MHz, 5-cell aluminum cavity; to a 1.2 MW klystron feeding four 476.3 MHz, HOM damped copper cavities. The system installation was completed in late November 2003 and the required accelerating voltage of 3.2 MV (800 kV/cavity) was very rapidly achieved soon after. This paper details the SPEAR3 RF system configuration and its new operating requirements, highlighting its installation and subsequent successful operation.  
 
TUPKF062 PEP-II RF System Operation and Performance positron, focusing, plasma, booster 1087
 
  • P.A. McIntosh, J. Browne, J.E. Dusatko, J.D. Fox, W.C. Ross, D. Teytelman, D. Van Winkle
    SLAC, Menlo Park, California
  The Low Energy Ring (LER) and High Energy Ring (HER) RF systems have operated now on PEP-II since July 1998 and have assisted in breaking all design luminosity records back in June 2002. Luminosity on PEP-II has steadily increased since then as a consequence of larger e+ and e- beam currents being accumulated. This has meant that the RF systems have inevitably been driven harder, not only to achieve these higher stored beam currents, but also to reliably keep the beams circulating whilst at the same time minimizing the number of aborts due to RF system faults. This paper details the current PEP-II RF system configurations for both rings, as well as future upgrade plans spanning the next 3-5 years. Limitations of the current RF system configurations are presented, highlighting improvement projects which will target specific areas within the RF systems to ensure that adequate operating overheads are maintained and reliable operation is assured.  
 
TUPKF063 Current Status of the Next Linear Collider X-band Klystron Development Program positron, klystron, plasma, booster 1090
 
  • D.W. Sprehn, G. Caryotakis, A.A. Haase, E.N. Jongewaard, C. Pearson
    SLAC, Menlo Park, California
  Klystrons capable of driving accelerator sections in the Next Linear Collider have been developed at SLAC during the last decade. In addition to fourteen 50 MW solenoid-focused devices and a 50 MW Periodic Permanent Magnet focused (PPM) klystron, a 500 kV 75 MW PPM klystron was tested in 1999 to 80 MW with 3-microsecond pulses, but very low duty. Subsequent 75 MW prototypes aimed for low-cost manufacture by employing reusable focusing structures external to the vacuum, similar to a solenoid electromagnet. During the PPM klystron development, several partners (CPI, EEV and Toshiba) have participated by constructing partial or complete PPM klystrons. After early failures during testing of the first two devices, SLAC has recently tested this design (XP3-3) to the full NLC specifications of 75 MW, 1.6 microseconds pulse length, and 120 Hz. This 14.4 kW operation came with a tube efficiency of 50%. The XP3 3 average and peak output power, together with the focusing method, arguably makes it the most advanced high power klystron ever built anywhere in the world. Design considerations and the latest testing results for these latest prototypes will be presented.  
 
TUPKF065 Comparison of Klystron and Inductive Output Tubes (IOT) Vacuum-electron Devices for RF Amplifier Service in Free-electron Laser positron, plasma, booster, focusing 1093
 
  • A. Zolfaghari, P. MacGibbon, W. North
    MIT/BLAC, Middleton, Massachusetts
  The MIT X-Ray Laser project, conceived to produce output in the 0.3 to 100 nanometer range, is based on a super-conducting 4-GEV linear accelerator, using 24 multi-cavity cryo-modules, each with its own dedicated RF amplifier, operating at 1.3 GHz. The continuous output of each amplifier is nominally 15 kW, with an optional repetitive pulse-modulation mode of 0.1 second pulse duration at one pulse per second. Although there are no fundamental restraints which preclude the consideration of any RF amplifier type, including solid-state or conventional triode or tetrode, the most appropriate current technology includes the Klystron and the IOT (Inductive Output Tube), also known by the CPI trade-name, Klystrode. The mechanisms by which the devices convert DC input power into RF output power are discussed. The devices are then compared with regard to availability (developmental or off-the-shelf), conversion efficiency, means of pulse-modulation, RF power gain, phase and amplitude stability (pushing factors), and acquisition and life-cycle costs.  
 
TUPKF066 34 Ghz, 45 MW Pulsed Magnicon: First Results plasma, booster, focusing, beamloading 1096
 
  • O.A. Nezhevenko, V.P. Yakovlev
    Omega-P, Inc., New Haven, Connecticut
  • J.L. Hirshfield, M.A. LaPointe
    Yale University, Physics Department, New Haven, CT
  A high efficiency, high power magnicon at 34.272 GHz has been designed and built as a microwave source to develop RF technology for a future multi-TeV electron-positron linear collider. To develop this technology, this new RF source is being perfected for necessary tests of accelerating structures, RF pulse compressors, RF components, and to determine limits of breakdown and metal fatigue. After preliminary RF conditioning of only about 200000 pulses, the magnicon produced an output power of 10.5 MW in 0.25 microsecond pulses, with a gain of 54 dB. Slotted line measurements confirmed that the output was monochromatic to within a margin of at least 30 dB.  
 
TUPKF067 High Power Magnicons at Decimeter Wavelength for Muon and Electron-Positron Colliders plasma, booster, focusing, beamloading 1099
 
  • O.A. Nezhevenko, V.P. Yakovlev
    Omega-P, Inc., New Haven, Connecticut
  • J.L. Hirshfield
    Yale University, Physics Department, New Haven, CT
  The CLIC drive linac requires pulsed RF amplifiers with a power of 50 MW at 937 MHz. In turn the muon collider requires 100 MW, 800 MHz RF amplifiers for the final stages of acceleration. In this paper conceptual designs of magnicons for these applications are presented. In addition to the typical magnicon advantages in power and efficiency, the designs offers substantially shorter tube length compared to either single- or multiple-beam klystrons.  
 
TUPKF068 JLAB Hurricane Recovery plasma, booster, focusing, beamloading 1102
 
  • A. Hutton, D. Arenius, F.J. Benesch, S. Chattopadhyay, E. Daly, V. Ganni, O. Garza, R. Kazimi, R. Lauze, L. Merminga, W. Merz, R. Nelson, W. Oren, M. Poelker, T. Powers, J.P. Preble, C. Reece, R.A. Rimmer, M. Spata, S. Suhring
    Jefferson Lab, Newport News, Virginia
  Hurricane Isabel, originally a Category 5 storm, arrived at Jefferson Lab on September 18 with winds of only 75 mph creating little direct damage to the infrastructure. However, electric power was lost for four days allowing the superconducting cryomodules to warm up and causing a total loss of the liquid helium. The subsequent recovery of the cryomodules and the impact of the considerable amount of opportunistic preventive maintenance provides important lessons for all accelerators complexes, not only those with superconducting elements. The details of how the recovery process was structured and the resulting improvement in accelerator availability will be discussed in detail.  
 
TUPKF072 Production and Performance of the CEBAF Upgrade Cryomodule Intermediate Prototypes plasma, booster, focusing, beamloading 1105
 
  • A-M. Valente, E. Daly, J.R. Delayen, M. Drury, R. Hicks, C. Hovater, J. Mammosser, H.L. Phillips, T. Powers, J.P. Preble, C. Reece, R.A. Rimmer, H. Wang
    Jefferson Lab, Newport News, Virginia
  • C. Thomas-Madec
    SOLEIL, Gif-sur-Yvette
  We have installed two new cryomodules, one in the nuclear physics accelerator (CEBAF) and the other in the Free Electron Laser (FEL) of Jefferson Lab. The new cryomodules consist of 7-cell cavities with the original CEBAF cell shape and were designed to deliver gradients of 70 MV/module. Several significant design innovations were demonstrated in these cryomodules. This paper describes the production procedures, the performance characteristics of these cavities in vertical tests, results of tests in the new cryomodule test facility (CMTF) as well as the commissioning in the CEBAF tunnel and FEL. Performances and limitations after installation in the accelerators are discussed in this paper along with improvements proposed for future cryomodules.  
 
TUPKF074 Niobium Thin Film Cavity Deposition by ECR Plasma plasma, booster, focusing, beamloading 1108
 
  • A-M. Valente, H.L. Phillips, H. Wang, A. Wu, G. Wu
    Jefferson Lab, Newport News, Virginia
  Nb/Cu technology for superconducting cavities has proven to be over the years a viable alternative to bulk niobium. Energetic vacuum deposition is a very unique alternative method to grow niobium thin film on copper. Single crystal growth of niobium on sapphire substrate has been achieved as well as good surface morphology of niobium on small copper samples. The design of a cavity deposition system is in development. This paper presents the exploratory studies of the influence of the deposition energy on the Nb thin film properties. Several possible venues to achieve Nb/Cu cavity deposition with this technique are also discussed along with the design of the cavity deposition setup under development.  
 
TUPKF075 Inductive Output Tubes for Particle Accelerators plasma, booster, focusing, beamloading 1111
 
  • H.P. Bohlen
    CPI, Palo Alto, California
  • E. Davies, P. Krzeminski, Y. Li, R.N. Tornoe
    CPI/EIMAC, San Carlos, California
  The Inductive Output Tube (IOT) is not widely used as an RF power source in particle accelerators yet, but this is about to change rapidly. One reason for this change is the IOT's "coming of age": almost twenty years of successful operation in television transmitters have lead to high refinement of IOT technology and proven reliability. The other reason is the fitness of the IOT to especially meet accelerator requirements: high efficiency, no need for power back-off to achieve fast feed-back regulation, and the possibility to pulse the RF without using a high-voltage modulator. Two classes of IOTs are available so far for application in particle accelerators. One of them consists of UHF external-cavity devices, frequency-tunable and producing output power levels up to 80 kW CW. The second class has been developed only recently. These are L-band IOTs with internal output cavities for 1.3 and 1.5 GHz, respectively, featuring output power levels between 15 and 30 kW CW. Extensive computer simulations have lead to the conclusion that even higher-power IOTs, such as a 300 kW peak-power, long-pulse L-band tube, are feasible.  
 
TUPKF076 Large Scale Production of 805-MHz Pulsed Klystrons for SNS plasma, booster, focusing, beamloading 1114
 
  • S. Lenci, E. Eisen
    CPI, Palo Alto, California
  The Spallation Neutron Source (SNS) is an accelerator-based neutron source being built in Oak Ridge, Tennessee, by the U.S. Department of Energy. The SNS will provide the most intense pulsed neutron beams in the world for scientific research and industrial development. CPI is supporting the effort by providing 81 pulsed klystrons for the super-conducting portion of the accelerator. The primary output power requirements are 550 kW peak, 49.5 kW average at 805 MHz, with an electron beam-to-rf conversion efficiency of 65% and an rf gain of 50 dB. Through January 2004, 47 units have been factory-tested. Performance specifications, computer model predictions, operating results, and production statistics will be presented.  
 
TUPKF077 Test Results for a 10-MW, L-band, Multiple-beam Klystron for TESLA plasma, booster, focusing, beamloading 1117
 
  • E.L. Wright, A. Balkcum, H.P. Bohlen, M. Cattelino, L. Cox, E. Eisen, F. Friedlander, S. Lenci, A. Staprans, B. Stockwell, L. Zitelli
    CPI, Palo Alto, California
  • K. Eppley
    SAIC, Burlington, Massachusetts
  The VKL-8301 high-efficiency, multiple-beam klystron (MBK), has been developed for the DESY Tera Electron volt Superconducting Linear Accelerator (TESLA) in Hamburg, Germany. The first prototype is built and will be tested in March of 2004. The prototype has been designed for long-life operation by utilizing the benefits inherent in higher-order mode (HM) MBKs. The primary benefit of HM-MBKs is their ability to widely separate individual cathodes. One of the major obstacles to the success of this approach is the design of the off-axis electron beam focusing system, particularly when confined-flow focusing is desired. We will show simulated and measured data which demonstrates a solution to this problem. High power test results will also be shown.  
 
TUPKF078 High Current Superconducting Cavities at RHIC plasma, booster, focusing, beamloading 1120
 
  • R. Calaga, I. Ben-Zvi, Y. Zhao
    BNL, Upton, Long Island, New York
  • J. Sekutowicz
    Jefferson Lab, Newport News, Virginia
  A five-cell high current superconducting cavity for the electron cooling project at RHIC is under fabrication. Higher order modes (HOMs), one of main limiting factors for high current energy-recovery operation, are under investigation. Calculations of HOMs using time-domain methods in Mafia will be discussed and compared to calculations in the frequecy domain. A possible motivation towards a 2x2 superstructure using the current five-cell design will be discussed and results from Mafia will be presented. Beam breakup thresholds determined from numerical codes for the five-cell cavity as well as the superstructure will also be presented.  
 
TUPKF079 A Low Noise RF Source for RHIC plasma, booster, focusing, beamloading 1123
 
  • T. Hayes
    BNL, Upton, Long Island, New York
  The Relativistic Heavy Ion Collider requires a low noise rf source to ensure that beam lifetime during a store is not limited by the rf system. The beam is particularly sensitive to noise from power line harmonics. Additionally, the rf source must be flexible enough to handle the frequency jump required for rebucketing (transferring bunches from the acceleration to the storage rf systems). This paper will describe the design of a Direct Digital Synthesizer (DDS) based system that provides both the noise performance and the flexibility required.

Work performed under the auspices of the US Department of Energy

 
 
TUPKF080 Photoemission Properties of Lead plasma, laser, booster, focusing 1126
 
  • J. Smedley, T. Srinivasan-Rao, J. Warren
    BNL, Upton, Long Island, New York
  • R.S. Lefferts, A.R. Lipski
    SBUNSL, Stony Brook, New York
  • J. Sekutowicz
    Jefferson Lab, Newport News, Virginia
  There is significant interest in the possibility of building a super-conducting injector for high average current accelerator applications. One candidate for such a cavity design is superconducting lead. Such an injector would be made considerably simpler if it could be designed to use lead as the photocathode, eliminating the need for Cesiated materials in the injector. In this paper we present a study of the photoemission properties of lead at several UV wavelengths, including a study of the damage threshold of electroplated lead under laser cleaning. A quantum efficiency in excess of 0.1% has been achieved for a laser cleaned, electroplated lead sample with a laser wavelength of 193 nm.  
 
TUPLT001 Beam Dynamics in 100 MeV S-Band Linac for CANDLE plasma, laser, booster, focusing 1129
 
  • B. Grigoryan, V.M. Tsakanov
    CANDLE, Yerevan
  The report presents the results of the beam dynamics study in 100 MeV S-band linear accelerator foreseen as an injector for the CANDLE light source. An impact of the excited longitudinal and transverse wake fields on the particle energy spread and the beam transverse emittance are given.  
 
TUPLT002 The Small-gap Undulator Impedance Study plasma, laser, booster, focusing 1132
 
  • M. Ivanyan, V.M. Tsakanov
    CANDLE, Yerevan
  The small gap undulator vacuum chamber resistive impedance model is developed. The vacuum chamber is considered as equal-radii tubes with the different wall materials (stainless steel "copper" stainless steel). The complete impedance was calculated as a sum of tubes and transitions impedances. The modal expansion method for transition impedance calculation is presented.  
 
TUPLT003 Transfer Matrices for the Coupled Space Charge Dominated Six-dimensional Particle Motion plasma, laser, booster, focusing 1135
 
  • D. Kalantaryan, Y.L. Martirosyan
    CANDLE, Yerevan
  In this paper we present exact analytical solutions for the particle motion in the six-dimensional phase space taking into account the space charge forces of fully linear coupled beam. The transfer matrices for the typical elements of magnetic lattice, such as drifts, cavities, quadrupole and dipole magnets have been obtained. The symplectic transfer matrices are used to develop a tracking program for the coupled betatron and synchro-betatron motion that enables the simulation of the tilted beam effects in circular accelerators.  
 
TUPLT006 Simple Analytic Formulae for the Properties of Nonscaling FFAG Lattices plasma, laser, booster, focusing 1138
 
  • S.R. Koscielniak
    TRIUMF, Vancouver
  • M.K. Craddock
    UBC & TRIUMF, Vancouver, British Columbia
  A hallmark of the "non-scaling" FFAG lattices recently proposed for neutrino factories and muon colliders is that a wide range of momentum is compacted into a narrow radial band; dL/L is of order 10-3 for dp/p of order unity. This property is associated with the use of F0D0 or FDF triplet lattices in which the F magnet provides a reverse bend. In this paper simple analytic formulae for key lattice properties, such as orbit displacement and path length as a function of momentum, are derived from thin-element models. These confirm the parabolic dependence of path-length on momentum observed with standard orbit codes, reveal the factors which should be adjusted to minimize its variation, and form a useful starting point for the thick-element design (for which analytic formulae are also presented). A key result is that optimized doublet, F0D0 and triplet cells of equal length and phase advance have equal path-length performance. Finally, in the context of a 10-20 GeV/c muon ring, the thin-element formulae are compared against lattice optical properties computed for thick-element systems; the discrepancies are small overall, and most discernible for the triplet lattices.  
 
TUPLT007 The CERN-SPL Chopper Concept and Final Layout plasma, laser, booster, focusing 1141
 
  • F. Caspers, Y. Cuvet, J. Genest, M. Haase, M. Paoluzzi, A. Teixeira
    CERN, Geneva
  The fast chopper for the CERN SPL (Superconducting Proton Linac) consists of a double meander structure with a beta (v/c) value of 8 % printed on an alumina substrate for the deflecting plates. Each chopper unit is 50 cm long and housed in a quadrupole magnet surrounding the vacuum chamber. The deflecting plates are operated simultaneously in a dual mode, namely traveling wave mode for frequencies above about 10 MHz and as quasi electro-static deflectors below. The deflecting structures are water-cooled to handle heating from beam losses as well as from the deflecting signal. A detailed mechanical layout is presented including the tri-axial feeding and termination technique as well as a discussion of the drive amplifier  
 
WEPLT013 Investigation of Space Charge Effects and Intrabeam Scattering for Lead Ions in the SPS focusing, bunching, beamloading, beamlosses 1843
 
  • H. Burkhardt, D. Manglunki, M. Martini, F. Roncarolo
    CERN, Geneva
  • G. Rumolo
    GSI, Darmstadt
  Space charge effects and intrabeam scattering usually play a minor role in high energy machines like the SPS. They can potentially become a limitation for the heavy ion beams needed for the LHC at the injection plateau in the SPS. Experimental studies on space charge limitations performed on low energy proton beams in the SPS will be described. Theoretical studies have been performed to predict emittance growth times due to intrabeam scattering using several different codes.  
 
WEPLT046 Localizing Impedance Sources from Betatron-phase Beating in the CERN SPS radiation, focusing, resonance, bunching 1936
 
  • F. Zimmermann, G. Arduini, C. Carli
    CERN, Geneva
  Multi-turn beam-position data recorded after beam excitation can be used to extract the betatron-phase advance between adjacent beam position monitors (BPMs) by a harmonic analysis. Performing this treatment for different beam intensities yields the change in phase advance with current. A local impedance contributes to the average tune shift with current, but, more importantly, it also causes a mismatch and phase beating. We describe an attempt to determine the localized impedance around the SPS ring by fitting the measured betatron phase shift with current at all BPMs to the expected impedance response matrix.  
 
WEPLT047 A Test Suite of Space-charge Problems for Code Benchmarking radiation, focusing, resonance, bunching 1939
 
  • A. Adelmann
    PSI, Villigen
  • J. Amundson, P. Spentzouris
    Fermilab, Batavia, Illinois
  • J. Qiang, R.D. Ryne
    LBNL/CBP, Berkeley, California
  A set of problems is presented for benchmarking beam dynamics codes with space charge. As examples, we show comparisons using the IMPACT, MaryLie/IMPACT, and MAD9P codes. The accuracy and convergence of the solutions as a function of solver algorithms, simulations parameters such as number of macro particles, grid size, etc. are studied.  
 
WEPLT048 Beam Dynamic Studies of the 72 MeV Beamline with a 'Super Buncher' radiation, focusing, resonance, bunching 1942
 
  • A. Adelmann, S. Adam, R. Dölling, M. Pedrozzi, J.-Y. Raguin, P. Schmelzbach
    PSI, Villigen
  A significant increase of the beam intensity increase of the PSI 590 MeV proton accelerator facility above 2 mA requires a higher accelerating voltage in the main RF cavities. A corresponding increase of the voltage in the flattop cavity would result in a complete rebuild of this device. As an alternative, a scheme with a strong buncher in the 72 MeV beam transfer line is being studied. The goal is to restore the narrow phase width (~ 2 deg/RF at 50 MHz) of the beam bunches observed at extraction from Injector 2 at injection into the Ring Cyclotron. If we can find and inject a stable particle distribution, as done in the Injector 2, the flat-top cavity might eventually be decommissioned. First results of multi particle tracking in full 6 dimensional phase space with space charge are presented.  
 
WEPLT049 Timekeeping Mechanism at SLS/APS Control System radiation, focusing, resonance, bunching 1945
 
  • B. Kalantari, T. Korhonen
    PSI, Villigen
  Time is one of the most important and critical parameters in a distributed control and measurement system. It is especially crucial when we need to interpret correlation of different archived process variables (PV) during the time. Advanced Light Source (APS) and Swiss Light Source (SLS) are using a very similar control system toolkit (EPICS) and the same mechanism for timekeeping. Many input/output controllers (IOC) around the accelerator complex (including beamlines), run under a real-time operating system, and carry out the controls and data acquisition. Each IOC is responsible of keeping its own local time and time-stamps the local PV?s but tightly synchronized with a central timing IOC. Dedicated timing hardware and network makes it possible to maintain synchronous timestamps with real-time clock. In this paper we describe the principle of this mechanism, its advantages, our experiences and further improvements.  
 
WEPLT050 Frequency Map Measurements at BESSY radiation, focusing, resonance, bunching 1948
 
  • P. Kuske, O. Dressler
    BESSY GmbH, Berlin
  With two dedicated diagnostic kicker magnets and a turn-by-turn, bunch-by-bunch beam position monitor frequency maps were measured under various operating conditions of the BESSY storage ring. Depending on the number and type of insertion devices in operation additional resonances show up. Details of the experimental setup as well as the data analysis are presented. The results will be compared with theoretical calculations which are based on the linear model of the storage ring lattice extracted from measured response matrices. Non-linear elements are added to the model in order to describe the effect of the strong sextupole magnets, the horizontal corrector magnets installed in these magnets, and of some of the insertion devices.  
 
WEPLT051 Sub-Picosecond Electron Bunches in the BESSY Storage Ring focusing, resonance, bunching, optics 1951
 
  • G. Wustefeld, J. Feikes, K. Holldack, P. Kuske
    BESSY GmbH, Berlin
  BESSY is a low emittance, 1.7 Gev electron storage ring. A dedicated, low alpha optics is applied to produce short electron bunches for coherent synchrotron radiation (CSR) in the THz range[*]. By a further detuning of the optics, stable pulses as short as 0.7 ps rms length were produced. The sub-ps pulse shape is analysed by an auto-correlation method of the emitted CSR. The CSR-bursting instability is measured and compared with theory to estimate the current for stable, sub-ps pulses. Present limits of the low alpha optics are discussed.

* M. Abo-Bakr et al., Phys. Rev. Lett. 88, 254801 (2002).

 
 
WEPLT052 A Method to Measure the Skew Quadrupole Strengths in the SIS-18 using Two BPMs focusing, bunching, optics, booster 1954
 
  • F. Franchi, T. Beier, M. Kirk, M. Moritz, G. Rumolo
    GSI, Darmstadt
  • R. Tomas
    BNL, Upton, Long Island, New York
  In the SIS-18 of GSI a new set of skew quadrupoles has been installed to improve the multi-turn-injection. A new method based on the measurement of the resonance driving terms has been proposed to cross-check the nominal values and polarities of their gradients. Once a beam is transversely kicked, it experiences oscillations whose spectrum contains both the betatron tune line and secondary lines. The amplitude of each line is proportional to the strength of the multipoles, such as skew quadrupoles and sextupoles, present in the lattice. In this paper a recursive algorithm to derive the magnet strength from the spectral lines and the application of this method to the eight skew quadrupoles in the SIS-18 are presented.  
 
WEPLT053 Dynamical Effects of the Montague Resonance focusing, bunching, optics, synchrotron 1957
 
  • I. Hofmann, G. Franchetti
    GSI, Darmstadt
  • J. Qiang, R.D. Ryne
    LBNL/CBP, Berkeley, California
  In high-intensity accelerators emittance coupling, known as Montague resonance, may be an issue if the tune split is small. For static tunes within the stop-band of this fourth order space charge driven coupling the final emittances may become equal (equipartition). Using 2D computer simulation we show, however, that slow crossing of the resonance leads to merely an exchange of emittances. In 3D this is similar, if the crossing occurs over a time-scale shorter or comparable with a synchrotron period. For much slower crossing we find, instead, that the exchange may be suppressed by synchrotron motion. We explain this effect in terms of the mixing caused by the synchrotron motion.  
 
WEPLT054 Electron Cloud Build up in Coasting Beams focusing, bunching, optics, synchrotron 1960
 
  • G. Rumolo
    GSI, Darmstadt
  • G. Bellodi
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  • K. Ohmi
    KEK, Ibaraki
  • F. Zimmermann
    CERN, Geneva
  Electrons could in principle accumulate in the potential of coasting beams of positively charged particles until a balance between the beam force and space charge force from the electrons is reached. But the continuous interaction between a non-ideal perturbed coasting beam and the cloud of electrons being trapped by it, together with the reflection and secondary emission processes at the inner pipe wall, can alter this picture and cause a combined cloud or beam transverse instability long before the concentration of electrons reaches the theoretical equilibrium value. The issue is addressed in this paper by means of combined build-up and instability simulations carried out with the HEADTAIL code.  
 
WEPLT055 Observation of Ultracold Heavy Ion Beams with Micrometer Size by Scraping focusing, electron, ion, bunching 1963
 
  • M. Steck, K. Beckert, P. Beller, B.  Franzke, F. Nolden
    GSI, Darmstadt
  The existence of an ordered beam state for low intensity, electron cooled heavy ion beams has been evidenced by a sudden reduction of the momentum spread. The detection of a similar effect in the transverse degree of freedom by non-destructive diagnostics is ruled out by the limited resolution of beam profile detectors. A method to probe the horizontal beam size of an electron cooled beam in a dispersive section has been developed. It is based on beam scraping and allows a resolution on the order of micrometers. This good transverse resolution for the cooled ion beam is achieved by precise changes of the ion energy which is varied by changes of the electron beam energy. The lower resolution limit due to power supply ripple is estimated to be below 1 micrometer. This method evidenced that the reduction of the momentum spread by one order of magnitude coincides with a reduction of the transverse beam emittance by 2-3 orders of magnitude, at least. A horizontal beam radius of a few micrometer could be demonstrated for electron cooled heavy ion beams with less than 1000 particles. This gives new evidence for the formation of an ordered beam arranged as a linear string of ions.  
 
WEPLT056 An Electron Cooling System for the Proposed HESR Antiproton Storage Ring focusing, ion, bunching, optics 1966
 
  • M. Steck, K. Beckert, P. Beller, A. Dolinskii, B.  Franzke, F. Nolden
    GSI, Darmstadt
  • V.V. Parkhomchuk, V.B. Reva, A.N. Skrinsky, V.A. Vostrikov
    BINP SB RAS, Novosibirsk
  The HESR storage ring in the proposed new international accelerator facility will provide high quality antiproton beams for experiments with an internal target. In order to achieve the design luminosity for collisions with a hydrogen target powerful beam cooling is required. For dedicated experiments ultimate resolution is demanded. Therefore it is foreseen to provide cooled antiproton beams in the energy range 0.8-14 GeV with an energy spread of 100 keV or better. According to computer simulations the required cooling rates can be achieved by electron cooling with an electron current of 1 A. The conceptual design of an electron beam device which is based on electrostatic acceleration of the electrons and their transport in longitudinal magnetic fields into a cooling section with a strong magnetic field of up to 0.5 T will be presented. This design will allow cooling in the magnetized regime in order to reach the required high cooling rates. Some novel features for the generation and regulation of the accelerating voltage and for the beam transport are proposed.  
 
WEPLT057 Simulation Results on Cooling Times and Equilibrium Parameters for Antiproton Beams at the HESR focusing, antiproton, bunching, optics 1969
 
  • A. Dolinskii, O. Boine-Frankenheim, B.  Franzke, M. Steck
    GSI, Darmstadt
  • A. Bolshakov, P. Zenkevich
    ITEP, Moscow
  • A.O. Sidorin, G.V. Troubnikov
    JINR, Dubna, Moscow Region
  The High Energy Storage Ring HESR is part of the "International Accelerator Facility for Ion and Antiproton Beams" proposed at GSI. For internal target experiments with antiproton beams in the energy range 0.8 GeV to 14.5 GeV a maximum luminosity of 5 inverse nbarn per second and a momentum resolution on the order of 10 ppm have to be attained. Electron cooling is assumed to be the most effective way to counteract beam heating due to target effects and intra-beam scattering. Cooling times and equilibrium parameters have been determined by means of three different computer codes: BETACOOL, MOCAC, and PTARGET. The results reveal that the development of fast, "magnetized" electron cooling with beam currents of up to 1 A and variable electron energies of up to 8 MeV in an extremely homogeneous longitudinal magnetic field of up to 0.5 T is crucial to achieve the required equilibrium beam parameters over the envisaged range of antiproton energies.  
 
WEPLT058 A Space Charge Algorithm for Ellipsoidal Bunches with Arbitrary Beam Size and Particle Distribution focusing, antiproton, bunching, optics 1972
 
  • G. Franchetti, A. Orzhekovskaya
    GSI, Darmstadt
  For the GSI future project beam loss control of a high intensity bunched beam stored in SIS100 for 106 turns is an important issue. In a recent study (G. Franchetti et al., Phys. Rev. ST Accel. Beams 6, 124201 (2003)) an analytical space charge algorithm was proposed, which allowed noise-free calculations over a large number of turns. Here we present a generalization of this algorithm to arbitrary 3D dimensions and arbitrary distributions observing ellipsoidal symmetry. Applications to long-term tracking with space charge are presented  
 
WEPLT059 Beam Loss Modeling for the SIS100 focusing, antiproton, bunching, optics 1975
 
  • G. Franchetti, I. Hofmann
    GSI, Darmstadt
  In long term storage dynamic aperture is typically regarded as the quantity which has to be maintained sufficiently large in order to prevent beam loss. In the SIS100 of the GSI future project, a beam size occupying a large fraction of the beam pipe is foreseen. This circumstance requires a careful description of the lattice magnetic imperfections. The dynamic aperture is estimated in relation with an optimization of the SIS100 working point. For a space-charge-free bunched beam, estimates of beam loss are computed and compared with dynamic aperture. The impact of space charge will be discussed, and preliminary results on its effect on dynamic aperture and beam loss are presented.  
 
WEPLT060 Linear Coupling Theory of High Intensity Beams focusing, antiproton, bunching, coupling 1978
 
  • G. Franchetti, I. Hofmann
    GSI, Darmstadt
  • M. Aslaninejad
    IPM, Tehran
  It is planned to use linear coupling in the SIS18 in order to fully or partially equilibrate the transverse emittances before transfer to the projected SIS100 synchrotron. In this paper we show that space charge significantly modifies the coupling mechanism. In particular the width of the stop-band is dominated by the space charge tune shift for weak skew strength. The conditions are discussed, under which slow crossing of the coupling resonance leads to the desired goal of equalizing emittances while maintaining a sufficient matching of the beam to the ring and extraction optics.  
 
WEPLT061 Influence of Beam Tube Obstacles on the Emittance of the PITZ Photoinjector focusing, antiproton, bunching, coupling 1981
 
  • S. Setzer, W. Ackermann, S. Schnepp, T. Weiland
    TEMF, Darmstadt
  For detailed analysis of space charge dominated beams inside an RF Photoinjector PIC-Codes like MAFIA TS2/3 can be used. While the interaction of particles with the sourrounding geometries are taken into account, the applicability of such codes is restricted due to simulation time and memory consumption as well as by numercial noise. Therefore only smaller sections of the whole injector can be calculated. On the other hand codes like ASTRA can be used to simulate the whole injector but no interaction between bunch and geometry is included. To make use of the individual advantages of each code discribed above an interface for bidirectional bunch exchange between the two programs has been implemented. This approach allows for applying the right simulation method depending on the physical effects under investigation. To demonstrate the importance of such an approach the results of detailed numerical studies of the impact of beam tube obstacles like the laser mirror on the achievable emittance of the PITZ RF Photoinjector further downstream will be presented.  
 
WEPLT062 Wakefield Calculations for TTF-II focusing, antiproton, bunching, coupling 1984
 
  • I. Zagorodnov, T. Weiland
    TEMF, Darmstadt
  • M. Dohlus
    DESY, Hamburg
  In this paper we estimate long- and short-range wake functions for new elements to be used in TESLA Test Facility (TTF) - II. The wake potentials of the LOLA-IV structure and the 3rd harmonic section are calculated numerically for very short bunches and analytical approximations for wake functions in short and long ranges are obtained by fitting procedures based on analytical estimations. The numerical results are obtained with code ECHO for high relativistic Gaussian bunches with RMS deviation up to 0.015 mm. The calculations are carried out for the complete structures (including bellows, rounding of the irises and the different end cell geometries) supplied with ingoing and outgoing pipes. The low frequency spectra of the wake potentials is calculated using the Prony-Pisarenko method.  
 
WEPLT081 Numerical Evaluation of Geometric Impedance for SOLEIL antiproton, damping, booster, target 2038
 
  • R. Nagaoka
    SOLEIL, Gif-sur-Yvette
  Good knowledge and minimisation of the coupling impedance is of great importance for the future storage ring SOLEIL, envisaged to operate in both high current multibunch and high bunch intensity modes. Three-dimensional computations of the geometric impedance of various vacuum chamber components have been made with the code GdfidL, which allows parallel processing with a cluster of computers, rendering the computation with a small mesh size and a long integrated distance feasible. Many treated objects were found to exhibit large asymmetry in the two transverse planes, as well as resonant behaviour at high frequencies, both of which being non-straightforward to follow with the conventional analytical methods and 2-dimensional calculations. In particular, strongly trapped modes found for the flange impedance resulted in an unacceptably low vertical multibunch instability threshold, which urged a modification of the original cavity-like structure. The dependence of the dipole chamber impedance on the vertical slot size was followed to determine the optimal slot opening. Characteristics of the total broadband impedance obtained, along with relative contributions are also presented.  
 
WEPLT082 General Performances of the Injection Scheme into the SOLEIL Storage Ring injection, antiproton, damping, booster 2041
 
  • M.-A. Tordeux, J. Da Silva, P. Feret, P. Gros, P. Lebasque, A. Mary
    SOLEIL, Gif-sur-Yvette
  The injection scheme of the electron beam into the Storage Ring of the SOLEIL synchrotron is presented. It corresponds to the new SOLEIL optics : 12 meter long straight section, 2.75 GeV energy, with in addition the requirement for top-up injection mode. Pulsed magnets are described, and in particular the passive septum magnet, the transverse position of which can be adjusted so as to optimise the Touschek beam Lifetime. Tracking of particles has been performed over a large number of turns, taking into account the magnet errors, the high chromaticities and the physical apertures all along the machine (limited vertical apertures due to low gap undulators). Statistical efficiency of the injection has been deduced. Specific requirements for top-up injection have been examined, such as the closure of the injection bump, the residual vertical field and the leakage fields from septa.  
 
WEPLT085 Vertcal Effective Impedance Mapping of the ESRF Storage Ring injection, antiproton, damping, vacuum 2050
 
  • T. Perron, L. Farvacque, E. Plouviez
    ESRF, Grenoble
  Transverse impedance increase due to installation of low gap vacuum chambers is a general effect observed in synchrotron light sources. ESRF has been sensitive to this increase of impedance, as its single bunch threshold has dramatically decreased. This paper presents a method based on closed orbit distortion measurements, witch allows to measure locally the vertical effective impedance. Results of measurements performed on low gap vacuum chambers and in-vacuum ondulators are presented. As an extension to this experiment, a new global method is discussed. This method, also based on closed orbit measurement allows measuring simultaneously all areas of high impedance in the machine  
 
WEPLT086 Non Gaussien Transverse Distributions in a Stochastic Model for Beam Halos injection, antiproton, damping, vacuum 2053
 
  • N. Cufaro Petroni
    INFN-Bari, Bari
  • S. De Martino, S. De Siena, F. Illuminati
    Universita' degli Studi di Salerno, Dipartimento di Fisica E.R. Caianiello, Baronissi
  The formation of the beam halo in charged particle accelerators is studied in a dynamical stochastic model for the collective motion of the particle beam. The density and the phase of the charged beam obey a set of coupled nonlinear hydrodynamic equations with time-reversal invariance. The linearized theory for this collective dynamics is given in terms of a classical Schroedinger equation. Self-consistent solutions with space-charge effects lead to quasi-stationary beam configurations with enhanced transverse dispersion and transverse emittance growth. In the limit of a frozen space-charge core it is possible to determine and study the properties of stationary, stable core-plus-halo beam distributions. We explore the effect of non-Gaussian transverse distributions. In this case the underling stochastic process is allowed to jump, and the transverse distribution tails are heavier than in the Gaussian case giving rise to a halo effect. The stationary transverse distribution plays the role of an attractor for every other distribution, and we give an estimation of the time needed by a non stationary, halo-free distribution to relax toward the stationary distribution with a halo.  
 
WEPLT090 Nonlinear Evolution of the Beam in Phase Space at Elettra injection, antiproton, damping, vacuum 2056
 
  • S. Di Mitri, L. Tosi
    ELETTRA, Basovizza, Trieste
  Phase space in the Elettra storage ring has been investigated. The beam is kicked and the coordinates of the bunch centroid are acquired for at least 1000 turns. A Hilbert transform has been used to deduce the evolution of beam phase space from position coordinates. Several nonlinear effects have been detected, such as the amplitude dependence of the betatron tune, the presence of high order and coupling resonances. Fixed points have been evidenced as well as the behaviour of the beam in their neighbourhood. Scans in lifetime versus tune confirm the limiting effect of the observed resonances on the region of regular motion.  
 
WEPLT091 Frequency Map Analysis with the Insertion Devices at ELETTRA antiproton, damping, vacuum, booster 2059
 
  • S. Di Mitri, L. Tosi
    ELETTRA, Basovizza, Trieste
  • L.G. Liu
    SSRF, Shanghai
  Frequency map analysis is a very efficient technique for the understanding of the resonances which may affect the stability of the electrons. Measurements correlated to simulations can provide a method to improve beam lifetime and injection efficiency that is particulary important in the case of top up operation. In this paper, the results of frequency map measurements and simulations for the ELETTRA storage ring are presented both for the bare lattice as well as for the case in which insertion devices are operational.  
 
WEPLT092 Equilibrium Longitudinal Distribution for Localized Regularized Inductive Wake antiproton, damping, vacuum, booster 2062
 
  • S. Petracca, T. Demma
    U. Sannio, Benevento
  • K. Hirata
    GUAS, Kanagawa
  In a recent paper [*] we have shown that a localized wake assumption and the Gaussian approximation for the longitudinal beam distribution function can be used to understand the nature of the stationary solutions for the inductive wake, by comparison between the resulting map and the Haissinski equation, which rules the (less realistic) case of a uniformly distributed wake. In particular we showed the non-existence of solutions of Haissinski's equation when the inductive wake strength exceeds a certain threshold [**] to correspond to the onset of chaos in the map evolving the moments of the beam distribution from turn to turn. In this paper we use the same formalism to confirm that as noted in [**] for Haissinski's equation, a steady state solution for the longitudinal phase space distribution function always exists if a physically regularized inductive wake, which satisfies an obvious causality condition, is used.

* S. Petracca and Th. Demma, Proc. of the 2003 PAC, IEEE Press, New York, 2003, ISBN 0-7803-7739-9, p.2996.** Y. Shobuda and K. Hirata, Part. Accel. vol. 62, 165 (1999).

 
 
WEPLT093 Electromagnetic Fields of an Off-axis Bunch in a Circular Pipe with Finite Conductivity and Thickness - I antiproton, damping, vacuum, booster 2065
 
  • S. Petracca, L. Cappetta, T. Demma
    U. Sannio, Benevento
  The electromagnetic field produced by a bunched beam in a circular pipe is usually computed under the assumption that the field penetration(skin depth) is far less than the wall thickness. Chao [*] gave a formula which exploits the wall thickness, but his result is restricted to the monopole term. Piwinski [**] treated the case of a metal coated ceramic wall, when the coating thickness is much smaller than the skin-depth, but his analysis is also limited to the monopole term.In this paper we solve the problem in full generality, by providing an exact (Green's functions) solution for the field of an off-axis point particle running at constant velocity in a circular pipe with finite wall conductivity and thickness.

* A.W. Chao, Phys. of Collective Beam Instab. in High En. Accel., Wiley,1993** S. Piwinski, DESY 1972/72

 
 
WEPLT094 Electromagnetic Fields of an Off-axis Bunched Beam in a Circular Pipe with Finite Conductivity and Thickness - II antiproton, damping, vacuum, booster 2068
 
  • S. Petracca, L. Cappetta, T. Demma
    U. Sannio, Benevento
  • R.P. Croce
    Universita' degli Studi di Salerno, Dipartimento di Fisica E.R. Caianiello, Baronissi
  The general exact solution exploited [*] is applied, introducing suitable dimensionless parameters, and using appropriate asymptotic limiting forms, to compute the wake field multipoles for the different paradigm cases of LHC and DAPHNE.

* R. P. Croce, Th. Demma, S. Petracca "Electromagnetic Fields of an Off-axis Bunch in a Circular Pipe with Finite Conductivity and Thickness", these proceedings

 
 
THPKF023 Studies using Beam Loss Monitors at ANKA emittance, beamloading, lattice, beamlosses 2311
 
  • F. Pérez, I. Birkel, K. Hertkorn, E. Huttel, A.-S. Müller, M. Pont
    FZK-ISS-ANKA, Karlsruhe
  ANKA is a synchrotron light source that operates in the energy range from 0.5 to 2.5 GeV. In order to investigate the electron beam losses, two kind of beam loss monitors have been installed: 24 Pin Diode from Bergoz distributed around the storage ring, and one Pb-glass calorimeter located in a high dispersion region. The Pin Diodes are used to obtain information about the distribution of the losses while the Pb-glass detector provides higher sensitivity. The Pin Diodes allow to locate and distinguish the regions of higher losses due to Touschek and Elastic scattering. Furthermore, regions of higher losses at injection have been identified. The Pb-glass detector has been used to determine the beam energy with the resonant spin depolarisation technique. A strong spin orbit resonance has been observed with both detectors.  
 
THPKF024 A STATE-OF-THE-ART 3 GEV BOOSTER FOR ASP booster, lattice, beamloading, beamlosses 2314
 
  • G. Georgsson, N. Hauge
    Danfysik A/S, Jyllinge
  • S.P. Møller
    ISA, Aarhus
  DANFYSIK A/S will build the full-energy booster for the Australian Synchrotron Project. The Booster will accelerate the beam from the injection energy of 100 MeV to a maximum of 3.0 GeV. The Booster shall accelerate either a single bunch or a bunch train up to 150 ns. The current accelerated to 3 GeV will be in excess of 0.5 and 5 mA for the two modes, respectively. The circumference of the Booster is 130.2 m, and the lattice will have four-fold super-symmetry with four straight sections for RF, injection, special diagnostics and extraction. The lattice is designed to have many cells with combined-function magnets (dipole, quadrupole and sextupole fields) in order to reach a very small emittance of around 30 nmrad. A small emittance is beneficial, in particular for top-up operation. Details of the lattice design and beam dynamics of the booster will be presented.  
 
THPKF025 Commissioning Report of the CLS Booster Synchrotron lattice, booster, beamloading, beamlosses 2317
 
  • G. Georgsson
    Danfysik A/S, Jyllinge
  • L. Dallin
    CLS, Saskatoon, Saskatchewan
  • S.P. Møller
    ISA, Aarhus
  • L. Præstegaard
    Århus Sygehus, Århus
  A full energy booster is produced and taken into operation for the Canadian Light Source. The Booster accelerates the beam from the injection energy of 200 MeV to a maximum of 2.9GeV. The results of the commissioning and the characterized beam parameters are reported  
 
THPKF026 An Update on the SESAME Light Source booster, beamloading, beamlosses, radiation 2320
 
  • D. Einfeld
    CELLS, Bellaterra (Cerdanyola del Vallès)
  • M. Attal, G. Vignola
    SESAME, Amman
  During the past three years, the SESAME machine design has been optimised gradually taking into consideration the users demand in the Middle East region. The earlier design concept was to upgrade BESSY I to an energy of 1GeV, now SESAME is a 2.5GeV 3rd generation light source. A recent design review has recommended changing the machine lattice and layout to give greater flexibility for future upgrading and modification, the longest possible beam lines and the longest possible insertion devices, all of that with the limitation of the space available for the machine within the building. By shifting the machine by 6m from the centre of the building (in one direction) it was possible to increase the circumference of the storage ring by 3.6m into 128.4m and beam lines with lengths of 37.7m achieved, while the longest beam line in the old design was only 33.1m, this also increased the total length of the beam lines from 378.2m in the old design into 391.0m. An outline of these optimisations with their influence on the machine output is presented here. Furthermore the beam dynamics, the design of the main components of the storage ring and the first set of beam lines will be discussed.  
 
THPKF027 A Concept for the Spanish Light Source CELLS beamloading, lattice, beamlosses, synchrotron 2323
 
  • D. Einfeld, J. Bordas, J. Campmany, S. Ferrer, M. Muñoz, M. Pont, F. Pérez
    CELLS, Bellaterra (Cerdanyola del Vallès)
  In May of 2003 the Spanish and Catalan Governments established a public Consortium for the construction, equipment and exploitation of a third generation Synchrotron Light Source. The foundation was based upon a proposal from 1997 to build a 2.5 GeV, 12-fold symmetry machine with a circumference of around 260 m. At present a re-design is being considered, based upon the following decisions: 1.) Electron energy of 3 GeV, 2.) Circumference around 280 m, 3.) Emittance smaller than 5 nm.rad, 4.) 16-fold symmetry lattice 5.) Full energy injector, 6.) Topping-up injection mode foreseen and 7.) Booster synchrotron and Storage ring housed in the same tunnel. Lattice considerations are given in an accompanying paper. In the present one we will give a project overview and explain key design decisions and overall schedule. Five beamlines will be design and construct in a first phase to cover the needs of the Spanish community. The definition of these beamlines will take place during 2004 involving the users community. Planned beam commissioning will be in 2009.  
 
THPKF028 Upgrade of the Cryomodule Prototype before its Implementation in SOLEIL beamloading, lattice, damping, beamlosses 2326
 
  • P. Bosland
    CEA/DSM, Gif-sur-Yvette
  • P. Bredy, S. Chel, G. Devanz
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • R. Losito
    CERN, Geneva
  • P. Marchand, K. Tavakoli, C. Thomas-Madec
    SOLEIL, Gif-sur-Yvette
  In the Storage Ring (SR) of the Synchrotron SOLEIL light source, two cryomodules will provide the maximum power of 600 kW required at the nominal energy of 2.75 GeV with the full beam current of 500 mA. A cryomodule prototype, housing two 352 MHz superconducting single-cell cavities with strong damping of the Higher Order Modes has been built and successfully tested in the ESRF storage ring. Even though the achieved performance (3 MV and 380 kW) does meet the SOLEIL requirement for the 1st year of operation, the cryomodule prototype will be upgraded before its installation in the SR early 2005. Modifications will be made on the internal cryogenic system, and also on the power and dipolar HOM couplers. That requires a complete disassembling and reassembling of the cryomodule, which is being carried out at CERN in the framework of collaboration between SOLEIL, CEA and CERN. Additional 3D RF calculations have been performed on the full SOLEIL RF structure in order to get a more detailed description of the dipolar modes damping and of the dipolar HOM couplers tuning. A second cryomodule, similar to the modified prototype, will be built and installed in the SR about one year later.  
 
THPKF029 Femto-second Electron Beam Slicing Project at SOLEIL beamloading, damping, beamlosses, radiation 2329
 
  • 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.