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klystron

Paper Title Other Keywords Page
MOPC007 Status and Upgrade Program of the FERMI@ELETTRA Linac linac, laser, gun, controls 79
 
  • G. D'Auria, A. O. Borga, S. Di Mitri, O. Ferrando, G. C. Pappas, A. Rohlev, A. Rubino, C. Serpico, M. Trovo, A. Turchet, D. Wang
    ELETTRA, Basovizza, Trieste
  FERMI@ELETTRA is a seeded FEL user facility under construction at Sincrotrone Trieste, Italy. It will use the existing normal conducting S-band linac and with the installation of seven accelerating sections received from CERN after the LIL decommissioning, will be operated at 1.2 GeV. After the successful commissioning of the new injector system of ELETTRA, the linac has been disconnected from the storage ring and now is being revised and upgraded with the installation of new important subsystems, i.e., a new photoinjector, bunch compressors, laser heater, additional accelerating structures, etc. Here a description of the upgrade program as well as the ongoing activities on the main parts of the machine are reported and discussed.  
 
MOPC008 The Impact of PSK Timing on Energy Stability of e-Beam at FERMI@ELETTRA linac, simulation, synchrotron, injection 82
 
  • G. D'Auria, P. Delgiusto, M. M. Milloch, C. Serpico, D. Wang
    ELETTRA, Basovizza, Trieste
  The existing linac sections S1-S7 at ELETTRA will be upgraded for the FERMI@ELETTRA FEL project. These seven sections are 3/4 π-mode backward traveling wave (BTW) constant-impedance structures, powered by 45-MW klystrons (Thales TH 2132A) and with a SLED system to increase the RF peak power. Because of the strict requirement on the pulse-to-pulse beam energy stability (<0.1%) of the FERMI@ELETTRA project, the impact of phase shift keying (PSK), the timing of phase flipping, on beam energy needs to be revisited and evaluated. Here the results obtained with a simulation model built up by use of MATLAB simulink are present and discussed.  
 
MOPC016 Status of the CUTE-FEL Project undulator, linac, electron, gun 103
 
  • S. Krishnagopal, B. Biswas, S. K. Gupta, U. Kale, A. Kumar, V. Kumar, S. Lal, P. Nerpagar, K. K. Pant, A. Patel
    RRCAT, Indore (M. P.)
  We are building a Compact Ultrafast TErahertz Free-Electron Laser (CUTE-FEL), designed to lase around 80 microns, driven by a 10 MeV electron beam, and using a 5 cm period, 2.5 m long undulator. We present the latest status of the project, including acceleration and commissioning trials.  
 
MOPC033 Sapphire - A High Peak Brightness X-Ray Source as a Possible Option for a Next Generation UK Light Source linac, gun, emittance, undulator 142
 
  • R. P. Walker, C. Christou, J. H. Han, J. Kay
    Diamond, Oxfordshire
  • R. Bartolini
    JAI, Oxford
  In the UK there is increasing interest in a radiation source which would provide ultra-fast (from 100 fs down to a few fs and potentially below) multi-keV X-ray pulses with high peak brightness, in order to study rapid dynamical processes in electronic and molecular systems, complementary to the newly operational Diamond Light Source which has been designed principally for high time-averaged X-ray brightness. In this paper we present the results of our initial studies for one option for a cost-effective, staged, linac based source suitable as a national facility which can act additionally as a portal to larger X-ray free-electron laser facilities in Europe, the US and Japan.  
 
MOPC057 R&D Energy Recovery Linac at Brookhaven National Laboratory gun, linac, electron, diagnostics 193
 
  • V. Litvinenko, D. Beavis, I. Ben-Zvi, M. Blaskiewicz, A. Burrill, R. Calaga, P. Cameron, X. Chang, K. A. Drees, G. Ganetis, D. M. Gassner, H. Hahn, L. R. Hammons, A. Hershcovitch, H.-C. Hseuh, A. K. Jain, A. Kayran, J. Kewisch, R. F. Lambiase, D. L. Lederle, G. J. Mahler, G. T. McIntyre, W. Meng, T. C. Nehring, B. Oerter, C. Pai, D. Pate, D. Phillips, E. Pozdeyev, T. Rao, J. Reich, T. Roser, T. Russo, K. Smith, J. E. Tuozzolo, D. Weiss, N. Williams, K. Yip, A. Zaltsman
    BNL, Upton, Long Island, New York
  • H. Bluem, M. D. Cole, A. J. Favale, D. Holmes, J. Rathke, T. Schultheiss
    AES, Medford, NY
  • J. R. Delayen, L. W. Funk, H. L. Phillips, J. P. Preble
    Jefferson Lab, Newport News, Virginia
  Collider Accelerator Department at BNL is in the final stages of developing the 20-MeV R&D energy recovery linac with super-conducting 2.5 MeV RF gun and single-mode super-conducting 5-cell RF linac. This unique facility aims to address many outstanding questions relevant for high current (up to 0.5 A of average current), high brightness energy-recovery linacs with novel Zigzag-type merger. We present the performance of the R&D ERL elements and detailed commissioning plan.  
 
MOPD004 CPI RF Components for the ILC electron, vacuum, gun, controls 454
 
  • T. A. Treado, S. J. Einarson, T. W. Habermann
    CPI, Beverley, Massachusetts
  Communications & Power Industries, Inc. (CPI) has active programs to refine key components for the European XFEL. These components, the fundamental power coupler and the multibeam klystron (MBK) are also suited for the International Linear Collider (ILC). CPI power couplers are manufactured to our customer's specifications using processes which are standard to the electron device industry as well as processes which are specific to power couplers. We have developed the capability of plating high-RRR copper on stainless steel. We have developed the capability of applying TiN coatings to ceramic windows. Both processes are done in-house under carefully controlled conditions. Both processes have been fully qualified. CPI has manufactured nearly 100 power couplers of various designs. Our presentation will focus on power couplers for the XFEL and the ILC. CPI is currently developing a second-generation, horizontal MBK for DESY. This MBK operates at 10 MW, at an RF frequency of 1.3 GHz, 1.5 ms pulse length, and 10 Hz pulse repetition rate. Our presentation will provide an update on this development program.  
 
MOPD010 Design of XFEL facility in Harima controls, undulator, site, heavy-ion 466
 
  • T. Kato, M. Fuse, T. Imagawa, Y. Yamano
    Nikken Sekkei Ltd.
  • S. Itakura, N. Kumagai, K. Oshima, T. Otsuka
    RIKEN/SPring-8, Hyogo
  The 700m-long 8 GeV XFEL that was launched by RIKEN is now under construction and will be operational in FY 2010. The strong point of the XFEL facility in Japan is compact under keeping high-performance by applying Spring-8 numerous breakthroughs in accelerator-driven light sources technology. In order to support the high-performance of XFEL, the building was designed with a few architectural ideas. In this paper we introduce the design of building foundation and ground so as to control the transformation of floor which the devices are fixed to, and the design of air conditioning so as to control the temperature change around the devices.  
 
MOPD015 Current Status of Development in TETD of High-power Vacuum Microwave Devices linac, electron, proton, power-supply 475
 
  • M. Niigaki
    Toshiba Electron Tubes & Devices Co., Ltd, Tokyo
  • K. Hayashi, M. Irikura, M. Sakamoto, H. Taoka
    TETD, Otawara
  • M. Y. Miyake, Y. Okubo, S. Sakamoto, Y. Yano
    Toshiba Electron Tubes & Devices Co., Ltd (TETD), Tochigi
  TETD (Toshiba Electron Tubes & Devices Co., LTD.) has been developing a wide variety of klystrons and input couplers in collaboration with some Japanese research institutes. This article presents recent results of the development including a C-band and an S-band pulsed klystrons for SPring-8 Joint Project for XFEL, 1.3-GHz horizontal MBK for DESY and a 1.3-GHz TTF-type input coupler for the European XFEL. As an application to fusion experimental devices, development of a 5-GHz, 500-kW CW klystron for KSTAR and a 170-GHz quasi CW gyrotron for ITER are also presented.  
 
MOPD016 ALS Storage Ring RF System Upgrade storage-ring, controls, power-supply, booster 478
 
  • K. M. Baptiste, J. Julian, S. Kwiatkowski
    LBNL, Berkeley, California
  ALS is one of the first third generation synchrotron light sources which has been operating since 1992 at Berkeley Lab. Presently, the ALS Storage Ring System is comprised of a single 330kW klystron feeding two normal-conducting single-cell RF cavities via a WR1800 circulator and magic-tee transmission system. The klystron has operated well beyond its expected lifetime and even though replacement klystrons are available from a different manufacturer, we have opted to build the replacement amplifier with a system of four Inductive Output Tubes, (IOT). The new amplifier system will use Cavity Combiners (CaCo) to combine IOT outputs and a magic-tee to combine IOT pairs to feed the existing transmission line connected to the cavities. The existing HVPS will be upgraded to interface with the four IOT amplifiers and its crowbar will be replaced with a series solid-state switch. The system is being designed to operate with the industry standard external cavity IOTs (80kW) and integral cavity IOTs (90-100kW). In this paper we will present the details of the upgrade of each of the sub-systems in the ALS Storage Ring RF System.  
 
MOPD022 New 1MW 704MHz RF Test Stand at CEA-Saclay cathode, linac, proton, cryogenics 490
 
  • S. Chel, M. Desmons, A. Hamdi, F. Peauger
    CEA, Gif-sur-Yvette
  In the frame of the european CARE/HIPPI programme, superconducting accelerating cavities for pulsed proton injectors are developed. Qualification of these 704 MHz RF structures fully equipped (housed in a helium tank, with tuning system and power coupler), requires to perform high power tests in the existing horizontal cryostat CryHoLab. During the last years, CEA-Saclay built and ordered the necessary RF equipments to make such a platform for high power RF tests in a cryogenic environment available to the partners in HIPPI and later on to any other interested European teams. The main components of the RF test stand (95 kV-275kVA DC High Voltage Power Supply, 50Hz modulator and 1MW 704.4MHz RF klystron amplifier) are now installed and tested. In this paper, we present the different components with a focus on the new design of the hard tube modulator to match the new specifications and the compatibility with the floating HVPS, the results of the HV and RF measurements performed and we give a brief description of the PXI-based controller for the interlocks and klystron auxiliary controls.  
 
MOPD023 Parametric Study of a Novel Coaxial Bunched Beam Space-charge Limit space-charge, electron, plasma, focusing 493
 
  • M. Hess
    IUCF, Bloomington, Indiana
  Recently, a non-trivial space-charge limit for off-axis bunched electron beams in a coaxial conducting structure was derived theoretically*. The space-charge limit describes the minimum strength of an external solenoidal focusing field which is needed to stabilize the beam’s center-of-mass motion in the presence of induced surface charges on the coaxial structure. In this paper, we perform a parametric study of the space-charge limit to numerically determine its dependency on the conducting structure geometry, i.e., the ratio of the inner and outer conductor radii, as well as its’ dependency on the transverse and longitudinal bunch distributions. As an application, we show how this parametric study can be important for the design of high-power microwave sources, such as the UC-Davis/SLAC 2.8 GHz coaxial ubitron oscillator**.

*M. Hess, accepted for publication in IEEE Trans. Plasma Sci. (2008).
**A. J. Balkcum et al. IEEE Trans. Plasma Sci., vol. 26, pp. 548-555, 1998.

 
 
MOPD025 Status of the 805-MHz Pulsed Klystrons for the Spallation Neutron Source cathode, gun, factory, electron 499
 
  • S. Lenci, E. L. Eisen
    CPI, Palo Alto, California
  • M. P. McCarthy
    ORNL, Oak Ridge, Tennessee
  Communications and Power Industries, Inc (CPI) produced 81 klystrons for the Spallation Neutron Source at Oak Ridge National Laboratory. The klystrons are rated for 550 kW peak at 805 MHz. Seventy units have accumulated 1.2M hours of filament operation and 820K hours of high voltage operation through January 2008. A higher power 700 kW version has been developed and is now in production with 12 of the 38 units on order delivered through January 2008. Performance specifications, computer model predictions, operating results, production statistics, and operational status will be presented.  
 
MOPD035 20 MW Pulse Amplifier Klystron with Multiple Frequency Two-Gap Bunching Resonators for Linear Electron Accelerators electron, bunching, focusing, vacuum 529
 
  • K. G. Simonov, A. N. Korolev, A. V. Mamontov
    ISTOK, Moscow Region
  A klystron design with a two-gap bunching resonator which provides interaction with electron beam by fields of multiple frequencies of two-gap resonator fundamental oscillations for increasing the klystron efficiency is being considered. At that the two-gap resonator is tuned to antiphased oscillation at operating frequency and to in-phase oscillation at the second harmonic. Such choice of frequency oscillation types allows to make the resonator compact and provide optimal conditions for electron beam interaction with microwave fields of the two-gap resonator both in antiphased and in-phase oscillation types. The relations for choosing two-gap resonator interaction area size providing a stable klystron operation without self-excitation are given. The compactness of the realized two-gap resonator with multiple frequencies allowed to locate it into klystron drift tube between the main resonators without increasing the klystron overall dimensions. The results of experimental research of klystron with such a two-gap resonator showed a possibility to increase its efficiency significantly.  
 
MOPD042 Design and Testing of the Horizontal Version of the Multi Beam Klystron for European XFEL Project electron, cathode, gun, linac 544
 
  • Y. Yano, M. Y. Miyake, Y. Okubo, S. Sakamoto
    Toshiba Electron Tubes & Devices Co., Ltd (TETD), Tochigi
  • Y. H. Chin
    KEK, Ibaraki
  • K. Hayashi, K. Tetsuka, H. Urakata
    TETD, Otawara
  Toshiba Electron Tubes & Devices (TETD) has been developing 10-MW L-band Multi-Beam Klystrons (MBKs) for the European XFEL project and possibly for future linear colliders. In order to allow horizontal installation in the XFEL tunnel, the horizontal version of MBK, MBK E3736H, has been designed, fabricated and tested by TETD. The MBK has six low-perveance beams operated at low voltage of less than 120 kV (for 10MW) and six ring-shaped cavities. In the successful acceptance testing at TETD in August 2007, the MBK achieved an output power of 10.3 MW at the beam voltage of 117 kV and at the RF pulse width of 1.5ms with efficiency of 67%. This test demonstrated that MBK E3736H fulfills all the requirements necessary as the RF power source of the XFEL linac.  
 
MOPP029 The First Measurement of Low-loss 9-cell Cavity in a Cryomodule at STF feedback, superconducting-RF, coupling 610
 
  • T. Saeki, M. Akemoto, S. Fukuda, F. Furuta, K. Hara, Y. Higashi, T. Higo, K. Hosoyama, H. Inoue, A. Kabe, H. Katagiri, S. Kazakov, Y. Kojima, H. Matsumoto, T. Matsumoto, S. Michizono, T. Miura, Y. Morozumi, H. Nakai, K. Nakanishi, N. Ohuchi, K. Saito, M. Satoh, T. Takenaka, K. Tsuchiya, H. Yamaoka, Y. Yano
    KEK, Ibaraki
  • T. Kanekiyo
    Hitachi Technologies and Services Co., Ltd., Kandatsu, Tsuchiura
  • J. Y. Zhai
    IHEP Beijing, Beijing
  We are constructing Superconducting RF Test Facility (STF) at KEK for the R&D of International Linear Collider (ILC) accelerator. In the beginning of year 2008, we installed one high-gradient Low-Loss (LL) type 9-cell cavity into a cryomodule at STF, where we assembled an input coupler and peripherals with the cavity in a clean room, and the assembled cavity packages were dressed with thermal shields and installed into a cryomodule. At the room-temperature, we performed the processing of capacitive-coupling input-coupler upto the RF power of 250 kW. At the temperature of 4 K, we measured the loaded Q of the cavity and the tuner was tested. At the temperature of 2 K, high-power RF was supplied from a klystron to the cavity and the performance of the cavity packeage was tested. This article presents the results of the first test of the Low-Loss (LL) 9-cell cavity package at 2 K in a cryomodule.  
 
MOPP083 Status of High Power Tests of Normal Conducting Single-cell Structures impedance, vacuum, damping, electron 742
 
  • V. A. Dolgashev, S. G. Tantawi
    SLAC, Menlo Park, California
  • Y. Higashi, T. Higo
    KEK, Ibaraki
  We report results of ongoing high power tests of single cell traveling wave and standing wave structures. These tests are part of an experimental and theoretical study of rf breakdown in normal conducting structures at 11.4 GHz*. The goal of this study is to determine the gradient potential of normal-conducting, rf powered particle beam accelerators. The test setup consists of reusable mode launchers and short test structures and powered by SLAC’s XL-4 klystron. The mode launchers and structures were manufactured at SLAC and KEK and tested in SLAC klystron test laboratory.

*V. A. Dolgashev, S. G. Tantawi, et al. “High Power Tests of Normal Conducting Single Cell Structures,” SLAC-PUB-12956, PAC07, Albuquerque, New Mexico, 25-29 June 2007, pp 2430-2432.

 
 
MOPP091 Upgrade of Input Power Coupling System for the SNS RFQ rfq, vacuum, coupling, linac 763
 
  • Y. W. Kang, A. V. Aleksandrov, P. E. Gibson, T. W. Hardek, C. Luck, R. C. Peglow, A. V. Vassioutchenko
    ORNL, Oak Ridge, Tennessee
  A RF input power coupler system has been developed for upgrade of input coupling to the RFQ in the SNS linac front-end. The design employs two coaxial loop couplers for 402.5 MHz operation. Two couplers are used in parallel to power the accelerating structure with up to 800 kW total peak power at 8% duty cycle. Each coupler loop has a coaxial ceramic window that is connected to each output of a magic-T waveguide hybrid splitter through a coaxial to waveguide transition. The coaxial loop couplers have been designed, manufactured, and high power processed. This paper presents the following: RF and mechanical designs of the couplers and system, procedure and result of high power RF conditioning, and test and operation results of the upgraded system.  
 
MOPP116 Commissioning of the Cornell ERL Injector RF Systems controls, linac, diagnostics, factory 832
 
  • S. A. Belomestnykh, J. Dobbins, R. P.K. Kaplan, M. Liepe, P. Quigley, J. J. Reilly, C. R. Strohman, V. Veshcherevich
    CLASSE, Ithaca
  Two high power 1300 MHz RF systems have been developed for the Cornell University ERL Injector. The first system, based on a 16 kWCW IOT transmitter, is to provide RF power to a buncher cavity. The second system employs five 120 kWCW klystrons to feed 2-cell superconducting cavities of the injector cryomodule. The sixth, spare klystron is used to power a deflecting cavity in a pulsed mode for beam diagnostics. A digital LLRF control stem was designed and implemented for precise regulation of the cavities’ field amplitudes and phases. All components of these systems have been recently installed and commissioned. The results from the first turn-on of the systems are presented.  
 
MOPP124 Commissioning of the 400 MHz LHC RF System feedback, controls, cryogenics, vacuum 847
 
  • E. Ciapala, L. Arnaudon, P. Baudrenghien, O. Brunner, A. Butterworth, T. P.R. Linnecar, P. Maesen, J. C. Molendijk, E. Montesinos, D. Valuch, F. Weierud
    CERN, Geneva
  The installation of the 400 MHz superconducting RF system in LHC is finished and commissioning is under way. The final RF system comprises four cryomodules each with four cavities in the LHC tunnel. Also underground in an adjacent cavern shielded from the main tunnel are the sixteen 300 kW klystron RF power sources with their high voltage bunkers, two Faraday cages containing RF feedback and beam control electronics, and racks containing all the slow controls. The system and the experience gained during commissioning will be described. In particular, results from conditioning the cavities and their movable main power couplers and the setting up of the low level RF feedbacks will be presented.  
 
MOPP157 Critical Magnetic Field Determination of Superconducting Materials coupling, pick-up, pulsed-power, electromagnetic-fields 919
 
  • A. Canabal, T. Tajima
    LANL, Los Alamos, New Mexico
  • V. A. Dolgashev, S. G. Tantawi
    SLAC, Menlo Park, California
  • T. Yamamoto
    UTNL, Ibaraki
  Using a 11.4 GHz, 50-MW, <1 μs, pulsed power source and a TE013-like mode copper cavity, we have been measuring critical magnetic fields of superconductors for accelerator cavity applications. This device can eliminate both thermal and field emission effects due to a short pulse and no electric field at the sample surface. A model of the system is presented in this paper along with a discussion of preliminary experimental data.  
 
TUPC023 Design of the Transverse C-band Deflecting Structure for Measurement of Bunch Length in X-FEL resonance, coupling, RF-structure, simulation 1098
 
  • H. Ego
    JASRI/SPring-8, Hyogo-ken
  • Y. Otake
    RIKEN/SPring-8, Hyogo
  In SPring-8, the 8 GeV X-FEL with a short length of about 700 m is under construction. An electron beam with a bunch length in duration of less than 200 fs is indispensable for stable and brilliant X-ray radiation. We planned to measure the short bunch length with a transverse RF deflector. A bunch measuring system including the deflector must be located within 15 m of a bunch compressor at a beam energy of 1.45 GeV. To install the system in the restricted space, we need a deflector generating a transverse deflecting voltage over 40 MV. Therefore a new C-band deflecting structure was designed. It is a periodic disk-loaded structure with a racetrack-shaped iris in the center of each disk. The deflecting resonant mode is the HEM11-5π/6 mode of a backward traveling-wave and its transverse shunt impedance is more than 12 MΩ/m. The racetrack-shaped iris serves both as a cell-to-cell coupler and a beam passing hole, prevents rotation of the deflection plane of the HEM11 mode and makes the deflecting mode resonant stably. We represent the details and merits of the C-band structure with the demanded performance in this paper.  
 
TUPC113 Beam Energy Compensation by RF Amplitude Control for Thermionic RF Gun and Linac Based Mid-infrared FEL controls, gun, electron, beam-loading 1329
 
  • H. Zen, T. Kii, R. Kinjo, K. Masuda, H. Ohgaki, S. Sasaki, T. Shiiyama
    Kyoto IAE, Kyoto
  Institute of Advanced Energy, Kyoto University has constructed a mid-infrared FEL facility which consists of a thermionic RF gun, a traveling-wave type accelerating tube and a halbach type undulator. The electron beam quality is critical for lasing FEL. However, we found that the beam energy after the accelerator tube decreased from 25 to 23.5 MeV (around 6%) during macro-pulse duration (~4μsec), because.the beam current increases from 65 to 120 mA during the macro-pulse due to the backbombardment effect in the RF gun. To compensate the energy drop and to minimize the energy spread over the macro-pulse, the amplitude of RF power fed to the tube was controlled. Since a precise micro-bunch interval required to build up the FEL, the RF phase was also controlled. As the result, the energy spread of the electron beam was greatly reduced from 6 to 0.8% in FWHM which was same with micro-pulse energy spread (~0.8%). The phase stability during macro-pulse was also improved from 10 to less than 2 degree.  
 
TUPC138 Development of a New Low-Level RF-Control-System for the S-DALINAC controls, diagnostics, electron, linac 1389
 
  • A. Araz, U. Bonnes, R. Eichhorn, M. Konrad, M. Platz, A. Richter
    TU Darmstadt, Darmstadt
  • U. Laier
    GSI, Darmstadt
  • R. Stassen
    FZJ, Jülich
  The Superconducting DArmstadt electron LINear ACcelerator S-DALINAC has a maximum energy of 130 MeV and beam currents of up to 60 μA. To reach this energy conveniently in cw, superconducting cavities with a high Q at a frequency of 3 GHz are used. In order to achieve minimal energy spread, the amplitude and phase the cavities have to be controlled strictly in order to compensat the impact of microphonic perturbations. The existing analog rf control system based on a self-exited loop, converts the 3 GHz signals down to the base band. This concept will also be followed by the new digital system currently under design. It is based on an FPGA in the low frequency part, giving a great flexibility in the control algorithm and providing additional diagnostics. For example it is possible to change the operational mode between self-exited loop and generator driven resonator within a second. We will report on the design concept, the status and the latest results measured with a prototype, including different control algorithms as well as beam loading effects.  
 
TUPC140 The Spallation Neutron Source Cryomodule Test Stand RF System controls, linac, radio-frequency, monitoring 1395
 
  • M. T. Crofford, T. W. Hardek, D. Heidenreich, Y. W. Kang, K.-U. Kasemir, S.-H. Kim
    ORNL, Oak Ridge, Tennessee
  • J. A. Ball, T. L. Davidson
    ORNL RAD, Oak Ridge
  The Spallation Neutron Source (SNS) has recently commissioned a cryomodule test facility for the repair and testing of the super-conducting cryogenic cavities. This facility utilizes the original 402.5/805 MHz Radio Frequency (RF) Klystron Test Stand as its power source along with dual Low Level RF (LLRF) control systems. One control system is based on the standard SNS Linac LLRF controls with a second system for open-loop only control. The system is designed to allow simultaneous testing of devices in the test cave and other devices which can be tested outside of the enclosure. Initial tests have shown good results; some improvements are yet to be implemented. This paper will provide an overview of the RF systems, safety systems, and interlocks.  
 
TUPC141 Concept and Implementation of the SC Cavity Resonance Frequency Monitor for the Digital RF Field Controller controls, resonance, laser, monitoring 1398
 
  • W. Jalmuzna, A. Napieralski
    TUL-DMCS, Łódź
  • S. Simrock
    DESY, Hamburg
  New generations of digital control systems offer large number of computation resources together with precise ADCs (analog to digital converters) and DACs (digital to analog converters) which can be used to generate almost any klystron driving signal. This gives the possibility to implement such features as digital SEL (self excited loop) and frequency sweep mode. They can be used to monitor resonance frequency of SC cavities. This information can be used by tuning system to adjust cavity tuner settings. Such functionality is valuable especially during the first RF station start up when the cavities may be detuned even by a large frequency. The paper presents the concept of such system and summarizes implementation and tests performed at FLASH facility (DESY, Hamburg).  
 
TUPC142 Performance of 24 Cavity Vector Sum Controller with Distributed Architecture controls, electron, laser, electromagnetic-fields 1401
 
  • W. Jalmuzna, A. Napieralski
    TUL-DMCS, Łódź
  The paper presents the test results of the digital vector sum control applied for 24 superconducting cavities driven by 1 klystron. The controller is based on FPGA chips and consists of multiple processing boards which communicate via optical fiber links. Flexible and scalable distributed architecture was designed and implemented to provide framework for the control algorithms. The tests were performed at FLASH (DESY, Hamburg) facility using ACC4, ACC5 and ACC6 modules. Results were compared to the existing DSP based system.  
 
TUPC146 Real Time, Distributed, Hardware-software Simulation of Multicavity RF Station for LLRF System Development in FLASH and XFEL simulation, controls, diagnostics, resonance 1413
 
  • P. Pucyk, S. Simrock
    DESY, Hamburg
  • W. Jalmuzna
    TUL-DMCS, Łódź
  The paper describes the implementation of distributed (FPGA, DSP, GPP) system for simulation of multiple TESLA cavities together with high power distribution chain. The applied models simulate the system behavior with the performance close to the response time of the real RF station and cryomodules. Parametrized architecture of the simulator allows to find compromise between the features of the model and the available resources it can be implemented in. The results of driving the simulator using the FLASH LLRF system are presented and compared with the real measurements. Proposed solution is the important tool for LLRF system development and testing, and can be, in many cases, a replacement for the tests in the real superconducting test facilities reducing the development costs and time.  
 
TUPC150 Ensemble Cavity Control System Simulation Using Pulse-to-pulse Calibration coupling, controls, simulation, alignment 1422
 
  • C. Serrano, L. R. Doolittle, A. Ratti, A. Vaccaro
    LBNL, Berkeley, California
  For cost reasons one klystron will supply RF power to multiple cavities in recent projects. Individual cavity field stability and optimal drive needs to be achieved considering beam propagation, cavity tuning, cavity coupling, and cable lengths. External environmental factors continuously modify physical properties of the accelerating structures and waveguides. Therefore a calibration system has been designed to adapt individual drive signals and vector-sum alignment in a pulse-to-pulse basis. An eight-cavity model and a calibration system have been tested in simulation using the hardware-software simulation tool developed at LBNL.  
 
TUPD024 Results of ELBE Window and Coupler Tests with a Resonant Ring vacuum, controls, resonance, coupling 1479
 
  • A. Buechner, H. Buettig, R. Schurig, G. Staats, A. Winter
    FZD, Dresden
  A new test bench based on a resonant ring has been built at ELBE to run window as well as coupler tests. The resonant ring is driven by a 10 kW klystron and allows tests with RF power up to 100 kW in CW mode and about 200 kW in pulsed mode. Coupler tests are done with liquid Nitrogen cooling under almost real conditions. The results of warm window and coupler tests in pulsed and CW mode are presented. Also details about the ring and a special designed coupler tip to rectangular waveguide transition are given.  
 
TUPD028 How to Stably Store Electron Beam in a Synchrotron Radiation Facility from the Point of View of an RF System Design storage-ring, synchrotron, electron, synchrotron-radiation 1485
 
  • Y. Kawashima, H. Ego, Y. Ohashi
    JASRI/SPring-8, Hyogo-ken
  • M. Hara
    RIKEN Spring-8, Hyogo
  In any synchrotron radiation facilities, the users wish that electron beams are stably stored without beam abortion for as long as possible. It must be recognized that RF system is a main cause of beam abortions. In order to store beam stably, it is necessary for staffs in charge of RF system to foresee various beam instabilities and to take measures. Before discussing coupled-bunch instability problems, one should understand some trivial issues such as ion trapping and fundamental acceleration frequency modulated by high voltage ripple. The former causes transverse mode instability and the latter shakes stored electron beam longitudinally in RF cavities. In newly designed synchrotron radiation facilities, those issues mentioned above should be suppressed before beam commissioning. As for other issues relating with RF system, we would like to state the importance of a water-cooling system with stable temperature for cavities, and the electric earth problem of low level RF system and high voltage power equipment of a klystron. We describe how we have managed those issues in designing of SPring-8 RF system of the storage ring.  
 
TUPP001 Alternating Gradient Operation of Accelerating Modules at FLASH controls, feedback, electron, laser 1523
 
  • V. Ayvazyan, G. Petrosyan, K. Rehlich, S. Simrock, E. Vogel
    DESY, Hamburg
  • H. T. Edwards
    Fermilab, Batavia, Illinois
  The free electron laser in Hamburg (FLASH) is a user facility providing high brilliant laser light for experiments. It is also an unique facility for testing the superconducting accelerator technology for the European XFEL and the international linear collider (ILC). The XFEL offers several beam lines to users. Within limits given by the beam delivery system the bunch pattern and beam energy should be adjustable independent for each beam line suggesting a time sliced operation. The ILC is focused on the highest gradients possible. FLASH accelerates beam at 5 Hz repetition rate. During accelerator studies the operation of the last accelerating modules with 10 Hz and alternating rf pulses has been established proving the feasibility of a time sliced operation at the XFEL. The rf pulses synchronous to the 5 Hz rf pulses are used for FEL operation whereas the gradient of the remaining rf pulse can be chosen independently and is used for long term high gradient operation gaining experience for the ILC. The operation of two different gradients within a single rf pulse is also available. The paper describes the technical setup, the rf control performance and the operational experience.  
 
TUPP015 Investigations into Cost Reductions of X-band Instrumentation resonance, instrumentation, controls, coupling 1559
 
  • D. Van Winkle, V. A. Dolgashev, J. D. Fox, S. G. Tantawi
    SLAC, Menlo Park, California
  The prohibitive costs of commercial test equipment for making fast and accurate pulsed phase and amplitude measurements at X-band result in decreased productivity due to shortages of shared equipment across the test laboratory. In addition, most current set-ups rely on the use of pulsed power heads which do not allow for the measurement of phase thereby limiting the flexibility of available measurements. In this paper, we investigate less expensive in-house designed instrumentation based upon commercial satellite down converters and widely available logarithmic detector amplifiers and phase detectors. The techniques are used to measure X-band pulses with widths of 50 ns to 10’s of usec. We expect a dynamic range of 30-40 dB with accuracies of less than ± 0.1 dB. We show results of the built and tested systems with particular attention focused on temperature performance and accuracy. Block diagrams of the down conversion scheme, and the architecture of a multi-signal X-band RF monitor and measurement system is illustrated. Measured results, and possible modifications and upgrades are presented.  
 
TUPP022 Measurements of Broad Band Impedance Related Longitudinal Properties of Electron Bunches at DELTA impedance, single-bunch, undulator, synchrotron 1577
 
  • R. Burek, H. Huck, G. Schmidt, T. Weis, K. Wille
    DELTA, Dortmund
  DELTA is a 1.5 GeV synchrotron light source which can be operated also at 550 MeV for FEL experiments. Due to interactions with the vacuum chamber, the beam induces wake fields, which act back on the beam and result in a disturbed bunch profile because of potential well distortion and turbulent bunch lengthening. These interactions limit the obtainable bunch length and achievable peak current and therefore strongly affect the FEL-operation. Recent results obtained by streak camera measurements have shown that for short bunches with maximum bunch lengths of 40 ps the longitudinal broad band impedance has to be scaled (SPEAR-scaling) to explain the measurements. The broad band impedance fits well to impedance measurements and calculations performed throughout the last years. The energy spread related to the bunch lengthening has been measured by analysing the undulator spectrum.  
 
TUPP157 Commissioning of L-band Electron Accelerator for Industrial Applications electron, bunching, power-supply, gun 1875
 
  • S. H. Kim, M.-H. Cho, W. Namkung, H. R. Yang
    POSTECH, Pohang, Kyungbuk
  • J. Jang, S. D. Jang, S. J. Kwon, J.-S. Oh, S. J. Park, Y. G. Son
    PAL, Pohang, Kyungbuk
  An intense L-band electron linear accelerator is under construction at CESC (Cheorwon Electron-beam Service Center) for industrial applications. It is capable of producing 10-MeV electron beams with a 30-kW average beam power. For high-power capability, we adopted 1.3 GHz, and the RF source is a 25-MW pulsed klystron with a 60-kW average RF output power. A pre-buncher is used before the bunching section, which is built-in with the regular accelerating sections. The accelerating structure is a disk-loaded waveguide with a constant-impedance operated in the 2π/3-mode. It is to be operated under the fully beam-loaded condition for high average power with the 6-μs pulse length and the 350-Hz repetition rate. In this paper, we present details of the accelerator system and commissioning results.  
 
WEOBM02 Lessons Learned from PEP-II LLRF and Longitudinal Feedback controls, feedback, simulation, kicker 1953
 
  • J. D. Fox, T. Mastorides, C. H. Rivetta, D. Van Winkle
    SLAC, Menlo Park, California
  • D. Teytelman
    Dimtel, San Jose
  The PEP-II B Factory is in the final phase of operation at 2X the design current and 4X the design luminosity. Since the original design the machine has added 8 1.2 MW Klystrons and 12 RF cavities, and the machine is operating with longitudinal instability growth rates roughly 5X in excess of the original estimates. Since commissioning there has been continual adaptation of the LLRF control strategies, configuration tools and new hardware in response to unanticipated technical challenges. This paper presents the LLRF and feedback system evolution from the original design estimates through to the 1.2·1034 final machine. We highlight issues of RF station stability, the interplay of LLRF configuration and low-mode (cavity fundamental driven) longitudinal instabilities, impacts of non-linearities and imperfections in the LLRF electronics, control of HOM driven beam instabilities and the development of configuration tools and measurement techniques to optimally configure the LLRF over the wide range of operating currents. We present valuable "lessons learned" which are of interest to designers of next generation impedance controlled LLRF systems.  
slides icon Slides  
 
WEPC015 Baseline Design of HLS Linac Upgrade linac, electron, quadrupole, gun 2019
 
  • G. Feng, W. Li, L. Shang, L. Wang, C.-F. Wu, H. Xu, S. C. Zhang
    USTC/NSRL, Hefei, Anhui
  The existing 200MeV linac of Hefei Light Source (HLS) mainly consists of electron gun, prebuncher, buncher, one 3m S-band linac section, and four 6m S-band linac sections. Energy gain of electron beam at the end of the linac is 200MeV and energy spread is ±0.8%. In order to improve the electron beam quality, An upgrade project is required. Four 80MW klystrons will be used to instead the old ones, which can improve the beam energy stability. This upgrade can also make it possible to increase the linac energy from 200 MeV to 400 MeV without changing the accelerating structure. In the meantime, New operation modes of HLS linac has been found by extensive computer modelling and optimization. Electron beam dynamics simulation from electron gun to the end of linac has been given, which considering space charge effects and wakefields.  
 
WEPC070 Further Optimisation of the Diamond Light Source Injector booster, injection, linac, storage-ring 2157
 
  • C. Christou, J. A. Dobbing, V. C. Kempson, A. F.D. Morgan, B. Singh, S. J. Singleton
    Diamond, Oxfordshire
  The Diamond Light Source injector consists of a 100MeV linac and a 3GeV full-energy booster, and has been providing beam to the storage ring since September 2006. System optimisation has continued throughout the first year of user operation at Diamond. Beam losses on injection into both the booster and storage ring have been minimised by optimisation of operating parameters and the stabilisation of injection elements, particularly the elimination of a linac energy beat. High level software has been developed to monitor turn-by-turn BPM data, allowing booster chromaticity to be measured. The same software generates an automatic log of storage ring frequency spectra on injection, enabling the parasitic measurement of storage ring tune, and can be used to provide information on storage ring impedance and chromaticity. Further optimisation of single bunch injection has been carried out in preparation for top-up operation, and top-up capability has been extended to provide a single bunch filling mode for the storage ring. Injection into the booster at low energy has been demonstrated, providing a mode of operation for the injection system in the event of a linac klystron failure.  
 
WEPC071 Installation and Commissioning of the 100 MeV Preinjector Linac of the New Elettra Injector gun, booster, linac, electron 2160
 
  • G. D'Auria, P. Borsi, A. Carniel, P. Delgiusto, O. Ferrando, A. Franceschinis, M. M. Milloch, A. Milocco, F. Pribaz, N. Sodomaco, M. Stefanutti, L. Veljak, D. Wang
    ELETTRA, Basovizza, Trieste
  • L. Picardi, C. Ronsivalle
    ENEA C. R. Frascati, Frascati (Roma)
  A new full energy injector has been installed and commissioned at Sincrotrone Trieste, the Italian Synchrotron Light Source Facility in Trieste. It consists of a 100 MeV Preinjector Linac (PL) followed by a 2.5 GeV Booster Synchrotron (BS), that will fill the Elettra Storage Ring (SR) with 2.0 GeV and 2.4 GeV electrons. Here a complete description of the preinjector linac and its characterization in terms of beam parameters will be presented and discussed.  
 
WEPC095 Progress in Raising the Energy of the CAMD Linac to 300 MeV linac, injection, simulation, controls 2216
 
  • Y. Wang, K. J. Morris, V. P. Suller, S. Wang
    LSU/CAMD, Baton Rouge, Louisiana
  The possibilities and methods for higher energy injection at CAMD have been discussed previously. All components of the former HELIOS 1 linac have now been transferred to CAMD from Jefferson Laboratory. It is planned to reconfigure the CAMD injector linac by installing one of the HELIOS accelerating sections in addition to the two existing CAMD sections, thereby increasing the energy to 300MeV. The optimum arrangement for installing the 300 MeV linac in the existing tunnel has been established. Meanwhile, the arrangements and upgrades of sub-systems are being prepared, simulations of the electron beam trajectory by MATLAB based linear accelerator program are being made, and recommissioning the major HELIOS linac components is underway. In the paper, the detailed technical design of the 300 MeV linac is proposed, the key parameters of the linac are presented, and the benefits of 300 MeV injection to the CAMD synchrotron radiation light source are mentioned.  
 
WEPP090 Accelerator Design for a 1/2 MW Electron Linac for Rare Isotope Beam Production linac, electron, target, gun 2728
 
  • S. R. Koscielniak, F. Ames, I. V. Bylinskii, R. E. Laxdal, M. Marchetto, A. K. Mitra, I. Sekachev, V. A. Verzilov
    TRIUMF, Vancouver
  TRIUMF, in collaboration with university partners, proposes to construct a megawatt-class electron linear accelerator (linac) as a photo-fission driver for radioactive ion beam production (RIB) for nuclear astrophysics studies and materials science. The design strategy, including upgrade path, for this cost-effective facility is elaborated. The 50 MeV, 10 mA, c.w. linac is based on TESLA/ILC super-conducting radio-frequency (SRF) technology at 1.3 GHz and 2K; and consists of an electron gun, buncher and capture sections, followed by 10 MeV and 40 MeV cryomodules containing one and four 9-cell cavities, respectively. Preliminary results from PARMELA beam dynamics simulations are presented. C. W. operation leads to challenges of large cryogenic heat load, input coupler power handling and beam loss mitigation similar to those encountered in ERL-based light sources. Unlike those sources there is no need for high beam brilliance, and a triode thermionic gun modulated at 1.3 GHz is employed; nor are short bunches required, and so the HOM excitation is modest. Many of the major sub-system components have been identified and where possible existing designs will be adopted.  
 
WEPP096 Nextef: The 100MW X-band Test Facility in KEK linear-collider, collider, controls, linac 2740
 
  • S. Matsumoto, M. Akemoto, S. Fukuda, T. Higo, N. Kudoh, H. Matsushita, H. Nakajima, T. Shidara, K. Yokoyama, M. Yoshida
    KEK, Ibaraki
  Nextef is a new X-band test facility in KEK. By combining the power from two klystrons, 100MW-class X-band RF power will be available. The facility is for researches on future high gradient linear accelerators. The commissioning operation of the whole facility was started in November 2007. It is planed to conduct high power testing of X-band accelerator structures as well as the fundamental researches such as the RF breakdown experiment with specially designed waveguides.  
 
WEPP106 High-gradient Experiments with Narrow Waveguides controls, vacuum 2758
 
  • K. Yokoyama, S. Fukuda, Y. Higashi, T. Higo, N. K. Kudo, S. Matsumoto
    KEK, Ibaraki
  High-gradient RF breakdown studies are presently being conducted at Nextef. To study the characteristics of different materials on high-field RF breakdown, we have performed experiments by using a reduced cross-sectional waveguide that has a field of approximately 200MV/m at an RF power of 100MW. A description of the high-gradient testing of copper and stainless-steel waveguides is reported.  
 
THPC012 Longitudinal Beam Dynamics Studies for the FERMI@ELETTRA Linac linac, electron, emittance, space-charge 2999
 
  • O. Ferrando, G. D'Auria
    ELETTRA, Basovizza, Trieste
  FERMI is a single-pass FEL project under construction at Sincrotrone Trieste Laboratory. It will be driven by the present warm S-band linac, upgraded by the addition of seven accelerating sections to bring its working energy up to 1.2 GeV. The goal of the project is to have an X-ray user facility covering the wavelength region between 100 -10 nm. The stringent constraints on the electron beam parameters required by FERMI, such as emittance, pulse to pulse energy and current stabilities, and time of arrival of the bunch at the input of the undulator chain, impose very stringent requirements on the parameters and operating conditions of the linac accelerating sections. To address the problem, i.e. evaluating the operating conditions of the machine and the flexibility of the adopted layout, beam dynamics studies with the LiTrack code have been performed. Here the results of different linac settings as well as the allowed variations in terms of RF phase and amplitude of the accelerating field are presented and discussed.  
 
THPC125 Modeling and Simulation of the Longitudinal Beam Dynamics-RF Station Interaction in the LHC Rings simulation, feedback, impedance, controls 3278
 
  • T. Mastorides, J. D. Fox, C. H. Rivetta, D. Van Winkle
    SLAC, Menlo Park, California
  • P. Baudrenghien, J. Tuckmantel
    CERN, Geneva
  A non-linear time-domain simulation has been developed to study the interaction between longitudinal beam dynamics and RF stations in the LHC rings. The motivation for this tool is to study the effect of RF station noise, impedance, and perturbations on the beam life and longitudinal emittance. It will be also used to determine optimal LLRF configurations, to study system sensitivity on various parameters, and to define the operational and technology limits. It allows the study of alternative LLRF implementations and control algorithms. The insight and experience gained from our PEP-II simulation is important for this work. In this paper we discuss properties of the simulation tool that will be helpful in analyzing the LHC RF system and its initial results. Partial verification of the model with data taken during the LHC RF station commissioning is presented.  
 
THPC156 Performances of the SPARC Laser and RF Synchronization Systems laser, linac, feedback, radiation 3354
 
  • A. Gallo, D. Alesini, M. Bellaveglia, G. Gatti, C. Vicario
    INFN/LNF, Frascati (Roma)
  The SPARC project consists in a 150 MeV S-band, high-brilliance linac followed by 6 undulators for FEL radiation production at 530 nm. The linac assembly has been completed and the SPARC scientific program is presently in progress. The low level RF control electronics to monitor and synchronize the RF phase of the accelerating structures along the linac and the laser shot on the photocathode has been commissioned and it is now fully operative. The laser synchronization is routinely monitored and slow drifts are automatically corrected by a dedicated shot-to-shot feedback system. A similar slow automatic regulation is implemented on each linac accelerating section acting either on low level or high power sliding lines. The phase noise in the 2 RF power stations is counteracted by fast intra-pulse phase feedback systems that have been developed and put in operation. Phase stability measurements taken over the whole synchronization system are reported, and performances of different synchronization architectures, micro-wave based or laser based, are compared.  
 
THPP079 Design of the High Current Linac of SPES Project linac, rfq, target, beam-transport 3545
 
  • A. Pisent, M. Comunian, E. Fagotti, A. Palmieri, P. A. Posocco
    INFN/LNL, Legnaro, Padova
  • F. Grespan
    Università degli Studi di Milano, Milano
  The proposed driver, composed by a four vanes RFQ and an Alvarez DTL, generates a high intensity beam, for an average current of 1.5 mA and an energy of 43 MeV, upgradable to 95 MeV. The high rep rate (50 Hz) is necessary for the correct mechanical behavior of the target. The accelerator is composed by the source TRIPS, built at LNS and now in operation at LNL, by the RFQ of TRASCO research program (5 MeV 30 mA), very advanced in the construction, and by a normal conducting Drift Tube Linac (DTL). This last accelerating structure is the same proposed for LINAC4 at CERN. A prototype of this structure, of interest for both projects, is in construction in Italy with the joint effort of CERN and LNL. The RFQ and the two tanks of the DTL are fed by 3 klystrons; the first one, with a power of 1.3 MW, is already at LNL, while the other two with a power of 2.5 MW each are the same adopted for LINAC4. The power supply of the RF system (50 Hz 0.6 ms) has been evaluated in details on the bases of the system in operation for the Japanese project JPARC. This paper illustrates the physical design and beam dynamics studies of this linac.