PAC07 - List of Keywords (klystron)

A B C D E F G H I K L M O P Q R S T U V W

klystron

Paper	Title	Other Keywords	Page
MOPAN015	Compact Waveguide Distribution with Asymmetric Shunt Tees for the European XFEL	linac, coupling, controls, simulation	176
	V. V. Katalev S. Choroba DESY, Hamburg
	In the European X-ray FEL 32 superconducting cavities (4 cryomodules with 8 cavities per module) are connected to one 10 MW multibeam klystron through a waveguide distribution system. The XFEL tunnel has limited space for the waveguide system and therefore a new more compact waveguide distribution has been developed. The waveguide distribution is based on a binary cell which consists of two circulators connected to a shunt tee with integrated phase shifters. Four binary cells are combined by three asymmetric pretunable shunt tees. The asymmetric shunt tees allow to change the RF power for each pair of cavities and to reach the maximum cryomodule gradient. In this paper we will present the status of the waveguide distribution system and report on the development of the different new waveguide components.

MOPAN019	Performance of the New Master Oscillator and Phase Reference System at FLASH	controls, monitoring, linac, free-electron-laser	188
	S. Simrock K. C. Czuba Warsaw University of Technology, Institute of Electronic Systems, Warsaw M. F. Felber, M. Hoffmann, B. Lorbeer, F. Ludwig, H. C. Weddig DESY, Hamburg
	The master oscillator and phase reference system at FLASH must provide several rf reference frequencies to widely spread locations with low phase noise and small long term phase drifts. The phase noise requirements of the 1300 MHz reference is of the order of 0.1 deg. while short and medium term phase stability is of of the order of 0.1 deg. and 1 deg. respectively. The frequency distribution system employs a temperature stabilized coaxial line for rf power distribution and a fiber optic system for the monitoring of phase drifts. Presented are the the concept, design and performance measured in the accelerator environment.

MOPAN041	Design of a Movable Synchrotron Radiation Mask with SiC Absorber for the Photon Factory Advanced Ring (PF-AR)	synchrotron, synchrotron-radiation, factory, photon	248
	T. Takahashi M. Izawa, S. Sakanaka, K. Umemori KEK, Ibaraki H. Suzuki, J. Watanabe Toshiba, Yokohama
	We have six rf cavities in the Photon Factory Advanced ring (PF-AR) at KEK. Three years ago, one of them was seriously damaged by the Synchrotron Radiation (SR) from the upstream of the cavity. In order to protect the cavities from SR, we intend to install SR masks nearby the cavities. The masks have to be positioned as close as possible to the beams in order to block the SR completely during the beam storage, and as far as possible during the beam injection. Therefore SR masks should be movable. Since it is placed under strong HOM power from the cavities, careful design is necessary for power dissipation. The basic structure of the movable masks is a coaxial wave-guide with cylindrical SiC absorber whose power capability is designed to be more than 1kW. We report the design of the movable SR masks and the result of rf power test.

MOPAS022	Controls, LLRF, and Instrumentation Systems for ILC Test Facilities at Fermilab	controls, instrumentation, linac, single-bunch	479
	M. Votava B. Chase, M. Wendt Fermilab, Batavia, Illinois
	Funding: Work supported by the U. S. Department of Energy under contract No. DE-AC02-76CH03000. The major controls and instrumentation systems for the ILC test areas and the NML test accelerator at Fermilab are discussed. The test areas include 3 separate areas for Vertical Superconducting RF Cavity Testing, Horizontal Cavity Testing, and NML RF and beam test area. A common control infrastructure for the test areas including a controls framework, electronic logbook and cavity database will be provided, while supporting components supplied by collaborators with diverse areas of expertise (EPICS, DOOCS, LabVIEW, and Matlab). The discussions on the instrumentation systems are focused on overview and requirements.

MOPAS061	LCLS RF Gun Feedback Control	controls, gun, resonance, simulation	572
	C. H. Rivetta R. Akre, P. Cutino, J. C. Frisch, K. D. Kotturi SLAC, Menlo Park, California
	Funding: Work supported by Department of Energy (USA) under contract # DE-AC02-76SF00515 The LCLC RF gun requires a water cooling thermal system to tune the resonance frequency of the cavity to 2856.03MHz. The RF system operates in pulsed mode with bursts of 2.5usec at a repetition rate of 30-120Hz. The thermal system operates in combination with the low-level RF system to set the operation point of the cavity. The Low-Level RF system controls the magnitude and phase of the cavity voltage and define slow signals to the thermal system. The thermal system operates by pre-heating / pre-cooling the water and mixing both channels to achieve the optimal temperature to control the cavity resonant frequency. The tune control of the RF gun include two systems with different dynamics. The dynamics of the thermal system is slow while the RF system is fast. Additionally, different actuators in the system present limits that introduce non-linearities to be taking into account during the start up process . Combining these characteristics, a controller is designed for the resulting hybrid system that allows convergence in large for all the operation conditions and achieve the performance in the magnitude and phase of the cavity voltage required around the operation point.

MOPAS062	Analysis of the Longitudinal Low-order Mode Beam Dynamics in PEP-II Rings at High Current Beams	simulation, damping, feedback, impedance	575
	T. Mastorides J. D. Fox, C. H. Rivetta, D. Teytelman, D. Van Winkle SLAC, Menlo Park, California
	Funding: Work supported by Department of Energy (USA) under contract # DE-AC02-76SF00515 PEP-II operations will increase the beam currents to 4A for LER and 2.2A for HER to achieve the final goal in luminosity. These magnitudes are challenging in part because they will push toward the limit the longitudinal low-order mode (LOM) beam stability due to beam loading. To analyze the behavior of both rings at high currents and understand the limits in the longitudinal feedback systems a simulation tool has been developed at SLAC. This tool is based on a reduced model of the longitudinal LOM dynamics of the beam interacting with the effective impedance presented by RF station. Simulations and measurements of the longitudinal beam behavior in both rings have been performed to understand the ultimate limit of the system. These studies have defined the impact of control loop parameters in the longitudinal beam dynamics, identified the poor performance of RF devices affecting the optimal performance of the RF stations and quantified the behavior of the longitudinal LOM beam dynamics. Results of sensitivity to parameter variations in the beam dynamics and limits in the maximum current that LER/HER can achieve based on the longitudinal beam stability are reported in this paper.

MOPAS071	A Precision 75kW, 25kV Power System for a Klystron Amplifier	controls, power-supply, feedback, vacuum	593
	L. Bees L. Simpson, A. Tydeman Lambda, Neptune, New Jersey
	A compact water-cooled high power, high voltage power supply system is described. The system must deliver an output voltage up to 25kV, and a current up to 4A to power a Klystron Amplifier. The amplifier demands very high voltage stability, low output voltage ripple, and low stored energy. The solution presented is based around Lambda's proven 303 series DC supplies to provide the bulk high voltage power, an advanced controller for high performance operation, and a precision filter/feedback assembly for low ripple and high accuracy. The system has demonstrated ripple of less than 0.015%, stability better than 10ppm per degree C, power factor of 0.92 and efficiency of 90%, with an output stored energy of less that 8J.

MOPAS079	Spallation Neutron Source (SNS) High Pulse Repetition Rate Considerations	target, controls, linac, proton	614
	M. P. McCarthy D. E. Anderson, I. E. Campisi, F. Casagrande, R. I. Cutler, G. W. Dodson, J. Galambos, D. P. Gurd, Y. W. Kang, K.-U. Kasemir, S.-H. Kim, H. Ma, B. W. Riemer, J. P. Schubert, M. P. Stockli ORNL, Oak Ridge, Tennessee
	Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U. S. Department of Energy. Increasing the pulse repetition rate (PRR) of the SNS Linac to its designed maximum of 60 Hz to provide 1.4 MW of beam on target is in progress. Operation above 60 Hz in the future to provide beam to a second target is also being considered. Increasing the PRR to 80 Hz would allow the additional pulses to be diverted to a second target. This paper discusses the impact of increasing the PRR on the SNS infrastructure including Radio Frequency (RF) systems and structures, the ion source, cryogenics, controls and the target.

TUXC03	Design and Status of the XFEL RF System	linac, electron, controls, linear-collider	841
	S. Choroba
	The RF system of the European XFEL under construction at present at DESY in Hamburg, Germany, consists of 27 RF stations. At a later point of time the number might be increased to 31. The RF system provides RF power at 1.3GHz for the superconducting cavities of the main linear accelerator, the cavities of the injector and the RF gun. Each station consists of a 10MW multiple beam klystron, a HV pulse modulator, HV pulse cables, a pulse transformer, an interlock system, a low level RF system, a waveguide distribution system and a number of auxiliary power supplies. This paper describes the layout of the RF system and summarizes the design and status of the main high power components.
	Slides

TUOAC02	Development and Testing of the ILC Marx Modulator	controls, shielding, vacuum, linear-collider	849
	G. Leyh
	Funding: Work supported by the U. S. Department of Energy under contract DE-AC02-76SF00515 Construction of the ILC 'Reference Design' Marx Modulator is complete, and testing is currently underway at SLAC. The Reference Design prototype is oil-free, air-cooled, and capable of delivering 120kV, 140A pulses at a rate of 5Hz. Total energy per pulse is 23,500 joules. Projected efficiency is greater than 96%. The Reference Design Marx modulator employs a stack of 12kV Marx modules that generate high-voltage output pulses directly from a 12kV input supply voltage. This direct switching eliminates the requirement for a massive transformer and reduces the capacitor bank size by more than a factor of four, yielding a considerably cheaper and more compact mechanical solution. Advantages of the Marx design include higher efficiency, smaller physical size, and a modular architecture that provides greater reliability and cost-effective PC board-level integration. This paper outlines the ILC Marx Modulator Development Program currently underway at SLAC. The paper presents detailed mechanical and electrical design diagrams, 3D field simulations, and operational test results for the full-scale Reference Design modulator prototype.
	Slides

TUPMN026	Conditioning of a New Gun Cavity Towards 60 MV/m at PITZ	gun, cathode, vacuum, electron	971
	S. Lederer G. Asova, J. W. Baehr, C. H. Boulware, H.-J. Grabosch, M. Hanel, S. Khodyachykh, S. A. Korepanov, M. Krasilnikov, B. Petrosyan, S. Rimjaem, T. A. Scholz, L. Staykov, F. Stephan DESY Zeuthen, Zeuthen K. Boyanov INRNE, Sofia L. H. Hakobyan YerPhI, Yerevan P. Michelato, L. Monaco, C. Pagani, D. Sertore INFN/LASA, Segrate (MI) R. Richter BESSY GmbH, Berlin J. Roensch Uni HH, Hamburg
	Funding: This work has partly been supported by the European Community, contracts RII3-CT-2004-506008 and 011935, and by the 'Impuls- und Vernetzungsfonds' of the Helmholtz Association, contract VH-FZ-005. Beginning 2007, a new gun cavity will be installed at the photo injector test facility at DESY in Zeuthen (PITZ). It will be conditioned towards gradients as high as 60 MV/m. This gradient is required for the operation of the European XFEL. Results from the conditioning for high peak power and high duty cycle will be reported.

TUPMN052	Completion of the Australian Synchrotron Storage Ring RF System Commissioning	controls, storage-ring, synchrotron, vacuum	1040
	S. Takama R. T. Dowd, A. Jackson, G. LeBlanc, K. Zingre ASP, Clayton, Victoria Y. Hirata, H. Kamikubo, Y. Nobusada, H. Suzuki Toshiba, Yokohama
	The installation and commissioning of the Australian Synchrotron Storage Ring RF System (SR RF System) was completed. SR RF System consists of four sets of 500MHz 150kW-CW klystron and 750kV normal conducting cavity. After the cavity aging, the RF System achieved 48 hours continuous operation in November 2006. The paper will present the design and commissioning results.

TUPMS047	Results of the SLAC LCLS Gun High-Power RF Tests	gun, cathode, coupling, electron	1296
	D. Dowell E. N. Jongewaard, J. R. Lewandowski, Z. Li, C. Limborg-Deprey, J. F. Schmerge, A. E. Vlieks, J. W. Wang, L. Xiao SLAC, Menlo Park, California
	Funding: SLAC is operated by Stanford University for the Department of Energy under contract number DE-AC03-76SF00515. The beam quality and operational requirements for the Linac Coherent Light Source (LCLS) currently being constructed at SLAC are exceptional, requiring the design of a new RF photocathode gun for the electron source. Based on operational experience at GTF at SLAC, SDL and ATF at BNL and other laboratories, the 1.6cell s-band (2856MHz) gun was chosen to be the best electron source for the LCLS injector, however a significant re-design was necessary to achieve the challenging parameters. Detailed 3-D analysis and design was used to produce nearly-perfect rotationally symmetric rf fields to achieve the emittance requirement. In addition, the thermo-mechanical design allows the gun to operate at 120Hz and a 140MV/m cathode field, or to an average power dissipation of 4kW. Both average and pulsed heating issues are addressed in the LCLS gun design. The first LCLS gun is now fabricated and has been operated with high-power RF. The results and analysis of these high-power tests will be presented.

TUPAN017	Development of a Coupled CH Structure for the GSI Proton Injector	proton, coupling, linac, simulation	1428
	G. Clemente L. Groening GSI, Darmstadt S. Minaev ITEP, Moscow H. Podlech, U. Ratzinger, R. Tiede IAP, Frankfurt am Main
	Funding: CARE (contract No RIICT-2003-506-395), GSI, BMBF The FAIR facility, under development at GSI, needs a new dedicated proton injector for the production of intense antiprotons secondary beams. This injector will accelerate protons from 3 to 70 MeV at a current of 70 mA, and due to the high voltage gain and shunt impedance will be based on CH cavities powered by a 2.5 MW, 325 MHz klystron. An innovative coupling cell containing one drift tube of length N-beta λ was developed to combine multicell drift tube modules of the CH-type (H210 mode).. In order to study this innovative coupling mechanism a scaled model of the second resonator of GSI Proton injector is under production at IAP. The according full scale prototype, 3 meter long coupled X MV resonator from MeV to MeV is under construction and will be power tested with a 2.5 MW klystron at GSI at the end of 2008. This paper describes in detail the coupled structure together with a general overview of the R&D results achieved on the CH-DTL's cavity.

TUPAN058	High Power Conditioning of the DTL for J-PARC	vacuum, linac, acceleration, pick-up	1517
	T. Ito H. Ao JAEA/LINAC, Ibaraki-ken H. Asano, T. Morishita JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken T. Kato, F. Naito, E. Takasaki, H. Tanaka KEK, Ibaraki
	For the J-PARC, DTL (Drift Tube Linac) is used to accelerate an H^- ion beam from 3MeV to 50MeV. The DTL consists of 3 tanks and the all tanks were installed in the accelerator tunnel for J-PARC. After the installation, the high power conditioning has been started in Oct. 2006. The required rf power levels for beam acceleration are about 1.08MW, 1.2MW and 1.03MW (the pulse length is 600μsec and the pulse repetition is 25Hz) for the 1st, 2nd and 3rd tanks, respectively. As a result of the conditioning, we have been achieved that the rf power levels are about 1.3MW, 1.45MW and 1.23MW of 1.2 times required power levels (the pulse length is 650μsec and the pulse repetition is 25Hz). In this paper, the results of the high power conditioning of the DTL tanks are described.

TUPAN062	RF Amplitude and Phase Tuning of J-PARC SDTL	linac, feedback, simulation	1529
	G. B. Shen H. Sako JAEA, Ibaraki-ken S. Sato JAEA/LINAC, Ibaraki-ken
	In the beam commissioning of J-PARC Linac, RF phase and amplitude of SDTL (Separate-type Drift Tube Linac) cavities have been tuned with a phase-scan method based on the beam-energy measurement. The output beam energy is measured with two FCTs (Fast Current Transformer) using the TOF (Time-Of-Flight) method. The detailed results of RF tuning for SDTL cavity is presented.

TUPAS002	RFQ Cold Model RF Measurements and Waveguide-to-Coaxial line Transition Design for the Front-End Test Stand at RAL	rfq, simulation, quadrupole, factory	1655
	Y. A. Cheng A. Kurup, P. Savage Imperial College of Science and Technology, Department of Physics, London A. P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon J. K. Pozimski STFC/RAL, Chilton, Didcot, Oxon
	A 324MHz four vane RFQ cold model has been built, as part of the development of a proton driver front end test stand at the Rutherford Appleton Laboratory (RAL) in the UK. This paper will present the results of RF measurements performed on the cold model, which include analysis of resonant modes, Q-value measurements and electric field profile measurements using a bead-pull perturbation method. These measurements were done before and after brazing of the four vanes and the results were compared to Microwave Studio simulations. Additionally a tuner has been designed, built and tested and the results will be presented together with the electromagnetic design of waveguide-to-coaxial line transition structures for the four vane RFQ.

TUPAS062	The LANSCE Refurbishment (LANSCE-R) Project	proton, controls, target, linac	1796
	K. W. Jones J. L. Erickson, F. R. Gallegos LANL, Los Alamos, New Mexico
	Funding: Work performed under the auspices of the U. S. Department of Energy At the core of the Los Alamos Neutron Science Center (LANSCE) accelerator lies an 800-MeV proton linac that drives user facilities for isotope production, proton radiography, ultra-cold neutrons, weapons neutron research and for various sciences using neutron scattering. LANSCE is in the planning phase of a refurbishment project that will sustain reliable facility operations well into the next decade. The general goals for LANSCE-R are to (1) preserve dependable operation of the linac and (2) increase the cost effectiveness of operations. Requirements can be met for overall beam intensity, availability, and reliability with long-term sustainability and minimal disruption to scheduled user programs. The baseline refurbishment project consists of replacing the 201 MHz RF systems, upgrading a substantial fraction of the 805 MHz RF systems, updating the control system, and replacing or improving a variety of diagnostics and accelerator subsystems. The plans for the various LANSCE-R improvements will be presented and the preliminary cost and schedule estimates will be discussed.

WEYAB02	Availability and Reliability Issues for ILC	simulation, power-supply, luminosity, linac	1966
	T. M. Himel J. Nelson, N. Phinney SLAC, Menlo Park, California M. C. Ross Fermilab, Batavia, Illinois
	Funding: Work supported by the U. S. Department of Energy under contract number DE-AC03-76SF00515. The International Linear Collider will be the largest most complicated accelerator ever built. For this reason extensive work is being done early in the design phase to ensure that it will be reliable enough. This includes gathering failure mode data from existing accelerators and simulating the failures and repair times of the ILC. This simulation has been written in a general fashion using MATLAB and could be used for other accelerators. Results from the simulation tool have been used in making some of the major ILC design decisions and an unavailability budget has been developed.
	Slides

WEPMN012	Beam Loading Compensation Using Real Time Bunch Charge Information from a Toroid Monitor at FLASH	controls, beam-loading, gun, undulator	2074
	E. Vogel C. Gerth, W. Koprek, F. Loehl, D. Noelle, H. Schlarb, T. Traber DESY, Hamburg
	Funding: Deutsches Elektronen-Synchrotron - DESY At pulsed linear accelerators, fast proportional rf control compensates beam loading sufficiently for single or a few bunches. In the case of long bunch trains, additional measures have to be taken commonly by adding a compensation signal to the rf drive signals calculated from the predicted beam intensity. In contrast to predictive methods, techniques based on real time beam measurements are sensitive to fast changes of the beam intensity and bunch patterns. At FLASH we apply a beam loading compensation scheme based on toroid monitor signals. This paper presents the compensation scheme, the calibration procedure and the effect on the beam.

WEPMN013	Testing of 10 MW Multibeam Klystrons for the European X-ray FEL at DESY	linac, power-supply, gun, cathode	2077
	V. Vogel A. Cherepenko BINP SB RAS, Novosibirsk S. Choroba, T. Froelich, T. G. Grevsmuehl, F.-R. Kaiser, V. V. Katalev, I. S. Sokolov, H. Timm DESY, Hamburg
	For the European XFEL project multibeam klystrons, which can produce RF power of 10 MW, at an RF frequency of 1.3 GHz, 1.5ms pulse length and 10Hz repetition rate, were chosen as RF power sources. So far three companies have produced this kind of new klystron. At DESY we installed a new test stand dedicated for testing this new type of RF power source. So far we have tested several tubes from Thales, Toshiba and CPI in our test stand. In this paper we give an overview of the test facilities and we summarize the current test results of the L-band multibeam klystrons (MBK).

WEPMN016	Installation and Commissioning of the New 150 kW Plant for the Elettra RF System Upgrade	power-supply, booster, insertion, insertion-device	2080
	A. Fabris M. Bocciai, C. Pasotti, M. Rinaldi ELETTRA, Basovizza, Trieste
	Elettra is the Italian third generation light source in operation in Trieste since 1993. The project of upgrade of the Elettra RF system has become necessary to provide the needed operating margins when all the insertion devices are operational and in view of possible increases in beam current and energy. The first phase of the project regards one of the four plants, which has been upgraded from 60 to 150 kW cw. The power amplifier has been built combining two 80 kW IOTs (inductive output tubes) by means of a switchless combiner. The amplifier and the power plant components have been installed in the second half of year 2006. A coaxial to waveguide transition has been specially designed to interface the coaxial coupler of the cavity to the waveguide power transmission system, taking into account the risks connected to power from the higher order modes excited by the beam in the cavity. After giving an overview of the project, this paper discusses the technical choices adopted, the tests performed during the installation phase and the commissioning of the new system with beam during machine operation.

WEPMN022	High Gradient Tests of C-band Accelerating System for Japanese XFEL Project	linac, power-supply, vacuum, collider	2095
	K. Shirasawa H. Baba, H. Matsumoto KEK, Ibaraki T. Inagaki, H. Kitamura, T. Shintake RIKEN Spring-8 Harima, Hyogo S. Miura MHI, Hiroshima
	The C-band (5712 MHz) choke-mode type accelerating structure will be used for SCSS. Since the C-band accelerator generates higher accelerating gradient than traditional S-band accelerator, it makes the machine size compact and the cost low. In order to confirm the performance of the C-band accelerating system for the 8 GeV XFEL machine, the system including the same accelerating structure and RF system have been installed in the SCSS prototype accelerator. In the prototype machine, four 1.8 m long C-band accelerating structures are used to accelerate electron up to 250 MeV. From November 2005, we have operated the C-band accelerator in the prototype machine with no serious problem. After the RF conditioning, accelerating gradient up to 35 MV/m was achieved. Since a lot of C-band accelerator units, about 70 klystrons and 130 accelerating structures, will be used for 8 GeV XFEL machine, it is necessary to investigate the damage due to the beam operation. Therefore, we plan to observe the inside of the accelerating structure and pulse compressor in early 2007. In this paper, we will report on the achieved performance and the inside observation of the C-band accelerator.

WEPMN023	Development of 10 MW L-Band Multi-Beam Klystron (MBK) for European X-FEL Project	cathode, gun, electron, simulation	2098
	Y. H. Chin K. Hayashi TETD, Otawara M. Y. Miyake, Y. Yano Toshiba, Yokohama
	A 10MW L-band Multi-Beam Klystron (MBK) has been developed and tested by Toshiba, Japan for the European XFEL and a future linear collider projects.? The Toshiba MBK has six low-perveance beams operated at low voltage of 115kV (for 10MW) and six ring-shaped cavities to enable a higher efficiency than a single-beam klystron for a similar power. After the successful acceptance testing at the Toshiba Nasu factory in March 2006, attended by a DESY stuff, the final acceptance test was done at DESY laboratory in June 2006. In these tests, the output power of 10.2MW, more than the design goal (10MW), has been demonstrated at the standard beam voltage of 115kV at the RF pulse length of 1.5ms and the beam pulse of 1.7ms at 10Hz. The efficiency was 66%. The robustness of the tube was also demonstrated by being operated continuously more than 24 hours above 10MW. A horizontal version of the Toshiba MBK is now under construction.

WEPMN028	Development of Digital Low-level RF Control System using Multi-intermediate Frequencies	controls, feedback	2110
	T. Matsumoto S. Fukuda, H. Katagiri, S. Michizono, Y. Yano KEK, Ibaraki Z. Geng IHEP Beijing, Beijing
	Digital low level rf (LLRF) control system has been developed in Superconducting RF Test Facility (STF) at KEK to carry out the accelerating electric field stability of 0.3% (rms) in amplitude and 0.3 degree (rms) in phase, respectively. In the digital LLRF system, rf probe signal from cavity is down-converted to intermediate frequency (IF) for acquisition at analog-to-digital converter (ADC) and the number of ADCs required is equal to the number of cavities. In order to decrease the number of ADCs, a new digital LLRF control system is under development. In this LLRF system, rf signals are down-converted to different IF and combined. The combined signal is detected with one ADC and I/Q components of each rf signal are calculated with digital signal processing. This paper describes a result of simulation and estimation using cavity simulator based on FPGA board about this new technique.

WEPMN029	Status of the Low-Level RF System at KEK-STF	feedback, controls, linac, linear-collider	2113
	S. Michizono S. Fukuda, H. Katagiri, T. Matsumoto, T. Miura, Y. Yano KEK, Ibaraki Z. Geng IHEP Beijing, Beijing
	RF field stabilities of less than 0.3%, 0.3deg. are required at STF llrf system. In order to satisfy these requirements, digital FB system using a FPGA is adopted. The FB system consists of a FPGA (VirtexIIPro30) with ten 16-bit ADCs and two 14-bit DACs. The rf (1.3 GHz) probe signals are downconverted to the IF (10 MHz) and directly acquired at ADCs. Total 8 cavities will be installed at STF-Phase 1 in 2007 and vector sum control of 8 cavity signals will be carried out. The performance of the FB system is examined with electric cavity simulators prior to the rf operation.

WEPMN039	Performance of J-PARC Linac RF System	controls, linac, feedback, beam-loading	2128
	T. Kobayashi S. Anami, Z. Fang, Y. Fukui, M. Kawamura, S. Michizono, K. Nanmo, S. Yamaguchi KEK, Ibaraki E. Chishiro, T. Hori, H. Suzuki, M. Yamazaki JAEA, Ibaraki-ken
	High power operation of all the RF systems of J-PARC linac was started for the cavity conditioning in October 2006. Twenty 324-MHz klystrons have powered the accelerating cavities successfully, and the beam commissioning was started in November 2006. The performance of the RF drive and control system will be presented.

WEPMN043	The Modulator Stability System for the BEPCII Klystron	feedback, target, linac, controls	2137
	L. Shen Y. L. Chi, Q. M. Dai, X. W. Yang IHEP Beijing, Beijing
	The stability of the modulator high voltage output pulse is the important target for the klystron. The stability of the BEPCII modulator is demanded less than 0.15%. To achieve this target, we use thyristor voltage regulator having feedback function to stabilize the DC high voltage of the modulator and the De-Qing circuit to stabilize the charging voltage. This paper describe the modulator stability system and the stabilization measurement .

WEPMN053	Test of 700MHz, 1MW Proto-type Klystron for PEFP	cathode, vacuum, gun, coupling	2158
	B. H. Chung K.-H. Chung KAPRA, Cheorwon J. S. Hong, J. H. Jeon, S. J. Noh Dankook University, Seoul S. K. Ko University of Ulsan, Ulsan
	High power and RF source of 700MHz and 1MW klystron, which has been designed and constructed by Korean Accelerator and Plasma Research Association, has been being tested. To test the primary performance of the klystron, a pulse power supply was used to manipulate a negative high voltage. We are currently reinforcing the protection circuit, and it is going on without much trouble as originally planned. In addition, a baking furnace for the klystron is under fabrication for the ultra high vacuum of better stability. We constructed various infrastructures such as baking furnace for the development of Klystron.

WEPMN073	A New Klystron Modulator for XFEL based on PSM Technology	controls, power-supply, factory, simulation	2200
	J. Alex M. Bader, J. Troxler Thomson Broadcast & Multimedia AG, Turgi
	Funding: Supported by DESY contract. Thomson Broadcast & Multimedia has been awarded a contract from DESY to design and build a prototype klystron modulator for the XFEL project. This modulator will be built in pulse step modulator (PSM) technology. This technology will allow to control the pulse form to achieve a maximum flatness of the pulse without tuning any high power components. The modulator will also have a built-in power regulation to prevent voltage flicker of the mains. The paper will give an overview about the principles of the modulator and presents the status of the design. It also shows simulation results about the expected performance.

WEPMN078	RF Cavity Development for FFAG Application on ERLP at Daresbury	impedance, electron, linac, extraction	2209
	E. Wooldridge C. D. Beard, B. D. Fell, P. A. McIntosh, B. Todd STFC/DL/ASTeC, Daresbury, Warrington, Cheshire R. M. Jones, B. Spencer UMAN, Manchester
	Funding for a non-scaling, Fixed Field Alternating Gradient (FFAG) facility has been approved for installation on the Energy Recovery Linac Prototype (ERLP) at Daresbury. The RF system specification for this project requires the development of a high efficiency, 1.3 GHz, normal conducting accelerating structure, capable of delivering the required accelerating voltage, whilst adhering to stringent space limitations imposed by the extremely compact nature of the FFAG ring. We have optimised a cavity design, providing the necessary acceleration and minimising the RF power requirements to match with commercially available power sources.

WEPMN085	The Advanced Photon Source Pulsed Deflecting Cavity RF System	photon, storage-ring, controls, electron	2224
	A. E. Grelick A. R. Cours, N. P. Di Monte, A. Nassiri, T. Smith, G. J. Waldschmidt ANL, Argonne, Illinois
	Funding: Work supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. The Phase I Advanced Photon Source Deflecting Cavity System for producing short X-ray pulses uses one multi-cell, S-band cavity to apply a deflecting voltage to the stored electron beam ahead of an undulator that supports a beamline utilizing short picosecond X-rays. Two additional multi-cell cavities are then used to cancel out the perturbation and redirect the electron beam along the path of its nominal orbit. The pulsed rf system driving the deflecting cavities is described. Design tradeoffs are discussed with emphasis on topology considerations and digital control loops making use of sampling technology in a manner consistent with the present state of the art.

WEPMN100	RF Design and Processing of a Power Coupler for Third Harmonic Superconducting Cavities	vacuum, electron, simulation, pick-up	2265
	J. Li E. R. Harms, T. Kubicki, D. J. Nicklaus, D. R. Olis, P. S. Prieto, J. Reid, N. Solyak Fermilab, Batavia, Illinois T. Wong Illinois Institute of Technology, Chicago, Illinois
	Funding: U. S. Department of Energy The FLASH user facility providing free electron laser radiation is built based on the TTF project at DESY. Fermilab has the responsibility for the design and processing of a third harmonic, 3.9 GHz, superconducting cavity which is powered via a coaxial power coupler. Six power couplers have been manufactured at CPI after successful design of the power coupler including RF simulation, multipacting calculation, and thermal analysis. The power couplers are being tested and processed with high pulsed power in an elaborate test stand at Fermilab now. This paper presents the RF design and processing work of the power coupler.

WEPMN101	Coupling Interaction Between the Power Coupler and the Third Harmonic Superconducting Cavity	coupling, beam-loading, injection, cryogenics	2268
	J. Li N. Solyak Fermilab, Batavia, Illinois T. Wong Illinois Institute of Technology, Chicago, Illinois
	Funding: U. S. Department of Energy Fermilab has developed a third harmonic superconducting cavity operating at the frequency of 3.9 GHz to improve the beam performance for the FLASH user facility at DESY. It is interesting to investigate the coupling interaction between the SRF cavity and the power coupler with or without beam loading. The coupling of the power coupler to the cavity needs to be determined to minimize the power consumption and guarantee the best performance for a given beam current. In this paper, we build and analyze an equivalent circuit model containing a series of lumped elements to represent the resonant system. An analytic solution of the required power from the generator as a function of the system parameters has also been given based on a vector diagram.

WEPMN112	Multichannel Vector Field Control Module for LLRF Control of Superconducting Cavities	controls, diagnostics, feedback, impedance	2298
	P. Varghese B. Barnes, J. Branlard, B. Chase, P. W. Joireman, D. W. Klepec, U. Mavric, V. Tupikov Fermilab, Batavia, Illinois
	The field control of multiple superconducting RF cavities with a single Klystron, such as the proposed RF scheme for the ILC, requires high density (number of RF channels) signal processing hardware so that vector control may be implemented with minimum group delay. The MFC (Multichannel Field Control) module is a 33-channel, FPGA based downconversion and signal processing board in a single VXI slot, with 4 channels of high speed DAC outputs. An LO input of upto 1.6 GHz can be divided down to provide 8 clock signals through a clock distribution chip. A 32-bit, 400MHz floating point DSP provides additional computational capability for calibration and implementation of more complex control algorithms. Both the FPGA and DSP have external SDRAM memory for diagnostic data and nonvolatile Flash memory for program and configuration storage. Multiple high speed serial transceivers on the front panel and the backplane bus allow a flexible architecture for inter-module real time data exchanges. An interface CPLD supports the VXI bus protocol for communication to a Slot0 CPU, with Ethernet connections for remote in system programming of the FPGA and DSP as well as for data acquisition.

WEPMN114	Modular Multiple Frequency RF Amplifier	controls, power-supply, feedback, ion	2304
	M. A. Kempkes M. P.J. Gaudreau, J. Kinross-Wright, I. Roth Diversified Technologies, Inc., Bedford, Massachusetts
	The construction and support of a wide range of RF amplifiers are significant cost components in the operation of the research community's accelerator facilities. This situation exists because amplifiers have been designed for a single application, often by multiple vendors, and therefore have very little commonality in their design, construction, and control interfaces for remote operation. To address these shortcomings, Diversified Technologies, Inc. (DTI) is developing a versatile and cost effective, modular RF amplifier design that can be employed across a wide range of RF amplifier requirements. Regardless of frequency or power, amplifiers built on this model feature commonality of design, controls system, and spares. A marriage of solid-state RF driver, power conditioning and control circuitry with high power Vacuum Electronic Device (VED) power amplifiers provide the ultimate in modular, cost-effective, and re-configurable RF power sources. In this paper, DTI will describe the modular RFA amplifier's topology and operating theory, and progress to date in the development of a prototype.

WEPMN116	Plans for Precision RF Controls for FERMI@ELETTRA	controls, linac, feedback, beam-loading	2310
	L. R. Doolittle J. M. Byrd, A. Ratti, J. W. Staples, R. B. Wilcox LBNL, Berkeley, California G. D'Auria, M. Ferianis, M. M. Milloch, A. Rohlev ELETTRA, Basovizza, Trieste M. W. Stettler CERN, Geneva
	FERMI@ELETTRA is a 4th generation light source under construction at Sincrotrone Trieste. It will be operated as a seeded FEL driven by a warm S-band linac presently serving as the injector for the ELETTRA storage ring. Operation as an FEL driver places much more stringent specifications on control of the amplititude and phase of the RF stations than in its present operation. This paper describes a conceptual design of an upgrade to the RF controls to achieve these specifications. The system consists of a stabilized distribution of the master oscillator signal providing a reference to local digital RF controllers . The RF reference distribution system takes advantage of recent breakthroughs in optical techniques where stabilized fiber lasers are used to provide a very accurate control of RF phases over long distances. The RF controller is based on recent improvements on modern digital systems, using a 14-bit high speed digitizer in combination with an FPGA and high speed DAC. This paper also presents experimental results of early tests performed as a feasibility study of the system.

WEPMN119	Equilibrium Theory of an Intense Elliptic Beam for High-Power Ribbon-Beam Klystron Applications	electron, simulation, focusing, vacuum	2316
	C. Chen J. Z. Zhou MIT/PSFC, Cambridge, Massachusetts
	Funding: Research supported by US Department of Energy, Office of High-Energy Physics, Grant No. DE-FG02-95ER40919 and Air Force Office of Scientific Research, Grant No. FA9550-06-1-0269. A concept for a high-power ribbon-beam klystron (RBK) employing a novel large-aspect ratio elliptic electron beam instead of a conventional circular electron beam is presented. Both cold-fluid and kinetic equilibrium theories are developed and applied in the design of the elliptic electron beam for the RBK. A small-signal theory is developed and applied in the design of the beam tunnel and the input, idler and output cavities. The electron gun and beam matching is being studied. Design results of a 10 MW 1.3 GHz RBK for the International Linear Collider (ILC) and of a 50 MW 22 GHz RBK for high-gradient research will be discussed.

WEPMS018	Superconducting Materials Testing with a High-Q Copper RF Cavity	cryogenics, superconductivity, monitoring, feedback	2370
	A. Canabal G. B. Bowden, V. A. Dolgashev, J. R. Lewandowski, C. D. Nantista, S. G. Tantawi SLAC, Menlo Park, California I. E. Campisi ORNL, Oak Ridge, Tennessee T. Tajima LANL, Los Alamos, New Mexico
	Magnesium diboride (MgB2) has a transition temperature (Tc) of ~40 K, i.e., about 4 times higher than niobium (Nb) that has been used for recent accelerators. The studies in the last 3 years have shown that it could have about one order of magnitude less RF surface resistance (Rs) than Nb and much less power dependence compared to high-Tc materials such as YBCO up to ~400 Oe. The tests to check the RF critical magnetic field, an important parameter to determine the feasibility for accelerator application, are underway. We are planning to test different thickness films and with different coating methods. This paper describes the results obtained so far. One of the objectives is to verify Gurevich's theory of getting higher critical field than Nb by adding a very thin layer (less than penetration depth) to Nb. In addition, some CW tests on power dependence up to higher magnetic fields are planned and some results will be shown if available at the time of conference.

WEPMS027	The Klystron RF Systems for the Indiana University LENS Accelerator	controls, linac, cathode, power-supply	2394
	W. Reass V. P. Derenchuk, T. Rinckel, G. Visser IUCF, Bloomington, Indiana D. Rees LANL, Los Alamos, New Mexico
	Funding: This work supported by the Indiana University Cyclotron Facility. This paper describes the Klystron RF systems for the Indiana University Low Energy Neutron Source (LENS) accelerator 425 MHz Radio Frequency Quadrupole (RFQ) and Drift Tube Linac (DTL) systems. Of interest in the power conditioning system is the design of the totem-pole grid-catch modulator for the mod-anode klystrons. This topology provides a fast rise and fall and closed loop regulation for the klystron mod-anode to cathode voltage, which minimizes RF amplitude and phase droop while maximizing efficiency. Another advantage is that short pulse high rep-rate operation is viable within the average power capabilities of the klystron. The 425 MHz, 1.25 MW klystron amplifier chain will also be detailed. Of final interest, is the digital low level RF system. This provides vector control of the cavity field using direct conversion, non-I/Q sampling architecture, at a sampling rate of 132 MHz with a 12-bit ADC. Four input and two output channels are integrated into a 6U VME module, with all DSP functions performed in Xilinx Spartan-3 field-programmable gate arrays. The design and implementation of these systems, coupled with LENS operational results, will be presented.

WEPMS028	Converter-Modulator Design and Operations for the ILC L-band Test Stand	impedance, linear-collider, collider	2397
	W. Reass C. Adolphsen, T. G. Beukers, C. Burkhart, R. L. Cassel, M. N. Nguyen, G. C. Pappas, R. Swent, A. C. de Lira SLAC, Menlo Park, California D. E. Anderson ORNL, Oak Ridge, Tennessee
	Funding: This work supported by Stanford Linear Accelerator Center, Oak Ridge National Laboratory, and the Department of Energy. To facilitate a rapid response to the International Linear Collider (ILC) L-Band development program at SLAC, a spare converter-modulator was shipped from Los Alamos. This modulator was to be a spare for the Spallation Neutron Source (SNS) accelerator at ORNL. The ILC application requires a 33% higher peak output power (15 MW) and output current (130 Amp). This presents significant design challenges to modify the existing hardware and yet maintain switching parameters and thermal cycling within the semiconductor component ratings. To minimize IGBT commutation and free-wheeling diode currents, a different set of optimizations, as compared to the SNS design, were used to tune the resonant switching networks. Additional complexities arose as nanocrystalline cores with different performance characteristics (as compared to SNS), were used to fabricate the resonant "boost" transformers. This paper will describe the electrical design, system modifications, modeling efforts, and resulting electrical performance as implemented for the ILC L-band test stand.

WEPMS029	LANSCE RF System Refurbishment	controls, power-supply, linac, proton	2400
	D. Rees G. O. Bolme, J. T. Bradley III, S. Kwon, J. T.M. Lyles, M. T. Lynch, M. S. Prokop, W. Reass, K. A. Young LANL, Los Alamos, New Mexico
	The Los Alamos Neutron Science Center (LANSCE) is in the planning phase of a refurbishment project that will sustain reliable facility operations well into the next decade. The LANSCE accelerator was constructed in the late 1960s and early 1970s and is a national user facility that provides pulsed protons and spallation neutrons for defense and civilian research and applications. The refurbishment will focus on systems that are approaching 'end of life' and systems where modern upgrades hold the promise for significant operating cost savings. The current baseline consists of replacing all the 201 MHz RF systems, upgrading a substantial fraction of the 805 MHz RF systems to high efficiency klystrons, replacing the high voltage systems, and replacing the low level RF cavity field control systems. System designs will be presented. The performance improvements will be described and the preliminary cost and schedule estimates will be discussed.

WEPMS033	LANSCE 201 MHz and 805 MHz RF System Experience	linac, vacuum, cathode, acceleration	2412
	K. A. Young G. O. Bolme, J. T.M. Lyles, M. T. Lynch, E. P. Partridge, D. Rees LANL, Los Alamos, New Mexico
	Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396 The LANSCE RF system consists of four RF stations at 201 MHz and 44 klystrons at 805 MHz. In the LANSCE accelerator, the beam source is injected into the RF system at 0.75 MeV. The beam is then accelerated to 100 MeV in four drift tube linac (DTL) tanks, driven at 201.25 MHz. Each 201 MHz RF system consists of a train of amplifiers, including a solid state amplifier, a tetrode, and then at triode. After the DTL, the beam is accelerated from 100 MeV to 800 MeV in the forty-four coupled cavity linac (CCL) tanks at 805 MHz. The machine operates with a normal RF pulse width of 835 microseconds at a repetition rate up to 120 Hz, and sometimes operates with a pulse width up to 1.2 microseconds for single pulses. This RF system has been operating for about 37 years. This paper summarizes the recent operational experience. The reliability of the 805 MHz and 201 MHz RF systems is discussed, and a summary the lifetime data of the 805 MHz klystrons and 201 MHz triodes is presented.

WEPMS036	LCLS LLRF Upgrades to the SLAC Linac	linac, controls, feedback, laser	2421
	R. Akre J. M. Byrd LBNL, Berkeley, California D. Dowell, P. Emma, J. C. Frisch, B. Hong, K. D. Kotturi, P. Krejcik, J. Wu SLAC, Menlo Park, California
	Funding: DOE The Linac Coherent Light Source at SLAC will be the brightest X-ray laser in the world when it comes on line. In order to achieve the brightness a 100fS length electron bunch is passed through an undulator. To creat the 100fS bunch, a 10pS electron bunch, created from a photo cathode in an RF gun, is run off crest on the RF to set up a position to energy correlation. The bunch is then compressed chicanes. The stability of the RF system is critical in setting up the position to energy correlation. Specifications derived from simulations require the RF system to be stable to below 100fS in several critical injector stations and the last kilometer of linac. The SLAC linac RF system is being upgraded to meet these requirements.

WEPMS039	High Power Tests of Normal Conducting Single-Cell Structures	vacuum, radiation, impedance, acceleration	2430
	V. A. Dolgashev Y. Higashi, T. Higo KEK, Ibaraki C. D. Nantista, S. G. Tantawi SLAC, Menlo Park, California
	Funding: This work was supported by the U. S. Department of Energy contract DE-AC02-76SF00515. We report results of the first high power tests of single-cell traveling-wave and standing-wave accelerating 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 converters and short test structures powered by SLAC?s XL-4 klystron. This setup was created for economic testing of different cell geometries, cell materials and preparation techniques with short turn-around time. The mode launchers and structures were manufactured at SLAC and KEK and tested in the klystron test laboratory at SLAC. V. A. Dolgashev et al., "RF Breakdown In Normal Conducting Single-Cell Structures," SLAC-PUB-11707, Particle Accelerator Conference (PAC 05), Knoxville, Tennessee, 16-20 May 2005, pp. 595- 599.

WEPMS043	An RF Waveguide Distribution System for the ILC Test Accelerator at NML	coupling, linac, linear-collider, collider	2442
	C. D. Nantista C. Adolphsen, G. B. Bowden, B. D. McKee, R. Swent SLAC, Menlo Park, California
	Funding: Work supported by the U. S. Department of Energy under contract DE-AC02-76SF00515. An ILC R&D facility is being constructed in the NML building at Fermilab which, in addition to an injector and beam dump with spectrometer, will contain up to three cryomodules worth of ILC-type superconducting 9-cell cavities, 24 in all. This linac will be powered by a single klystron. As part of SLAC?s contribution to this project, we will provide a distribution network in WR650 waveguide to the various cavity couplers. In addition to commercial waveguide components and circulators and loads developed for TESLA, this sytem will include adjustable tap-offs, and customized hybrids. In one configuration, the circulators will be removed to test pair-wise cancellation of cavity reflections through hybrids. The system will be pressurized with nitrogen to 3 bar absolute to avoid the need for SF6 at windows or circulator. The full distribution for the first cryomodule will be delivered and installed later this year. We describe the design of the system and completed RF testing.

WEPMS044	High Power Switch for the SMTF Modulator	controls, monitoring, power-supply, superconducting-RF	2445
	M. N. Nguyen R. L. Cassel SLAC, Menlo Park, California
	Funding: Work supported by the Department of Energy under contract No. DE-AC03-76SF00515. A compact, water cooled, high power switch for the Superconducting Module Test Facility (SMTF) long-pulse klystron modulator has been designed and implemented at the Fermi National Accelerator Laboratory (FNAL). This solid-state switch is composed of six series devices, each having a rating of 4.5 kV at 2000 Adc. Latest generation, press-pack IGBT modules are utilized to reduce the physical size and complexity of the switch assembly. The new switch and its associated controller provide a high degree of redundancy and fail-safe operation, which meets the modulator requirements. This paper describes the general switch assembly, IGBT protection and control schemes, and test results.

WEPMS045	Power Modulators for FERMI Linac's Klystrons.	controls, linac, induction, vacuum	2448
	G. C. Pappas G. D'Auria, P. Delgiusto, L. Veljak ELETTRA, Basovizza, Trieste
	The conventional line type modulators used for ELETTRA will have to be replaced for FERMI due to the increase in the pulse repetition frequency (PRF) from 10 to 50 Hz. The requirements for the FERMI modulator are as follows. The klystron used is a Thales TH2132 with a microperviance of 1.9-2.1 uA/V(3/2). The peak voltage from the modulator is 320 kV, and the current is 350 A. The pulse width is 4.5 us, with a PRF of 50 Hz. Flat top should be better than ?0.5 % of the peak voltage. Prototypes for an upgraded line type modulator and a solid state induction type modulator[1] are in fabrication. The solid state design uses eight induction cells, each cell driven by two parallel Insulated Gate Bipolar Transistors (IGBT). Each IGBT will power a METGLAS 2605CO core with 4 kV and 3 kA for up to 5 us. A single turn is passed through the aperture of each of the cells, inductively adding the pulse voltages. The output from the modulator is then fed to a conventional pulse transformer to reach the 320 kV requirement. This paper presents the system design of both modulator types as well as details of the IGBT drivers, control electronics, IGBT and klystron protection and test data. 1. "NLC Hybrdi Solid State Induction Modulator" R. L. Cassel, etal, Lubeck, Germany, Linac 2004.**

WEPMS047	Selecting RF Amplifiers for Impedance Controlled LLRF Systems - Nonlinear Effects and System Implications	controls, impedance, simulation, feedback	2451
	J. D. Fox T. Mastorides, C. H. Rivetta, D. Van Winkle SLAC, Menlo Park, California
	Funding: Work supported by the U. S. Department of Energy under contract #DE-AC02-76SF00515 Several high-current accelerators use feedback techniques in the accelerating RF systems to control the impedances seen by the circulating beam. These Direct and Comb Loop architectures put the high power klystron and LLRF signal processing components inside feedback loops, and the ultimate behavior of the systems depends on the individual sub-component properties. Imperfections and non-idealities in the signal processing leads to reduced effectiveness in the impedance controlled loops. In the PEP-II LLRF systems non-linear effects have been shown to reduce the achievable beam currents, increase low-mode longitudinal growth rates and reduce the margins and stability of the LLRF control loops. We present measurements of the driver amplifiers used in the PEP-II systems, and present measurement techniques needed to quantify the small-signal gain, linearity, transient response and image frequency generation of these amplifiers. Results are presented from measurements of 5 different types of amplifiers, and the trade-offs in selecting between them highlighted.

WEPMS054	45 MW, K-Band Second-Harmonic Multiplier for Testing High-Gradient Accelerator Structures	coupling, gun, electron, simulation	2466
	V. P. Yakovlev J. L. Hirshfield Omega-P, Inc., New Haven, Connecticut S. Kazakov KEK, Ibaraki
	Funding: Research supported by the Department of Energy, Division of High Energy Physics A relatively simple and inexpensive two-cavity 45 MW, 22.8 GHz second-harmonic multiplier is considered as an RF source for High-Gradient experiments. The design is to be based on use of an existing SLAC electron gun, such as the XL-4 gun. RF drive power would be supplied from a 50 MW SLAC klystron and modulator, and a second modulator would be used to power the gun in the multiplier. An important feature of the harmonic multiplier is TE 01 circular waveguide for output RF power extraction.

WEPMS074	Design and High Power Processing of RFQ Input Power Couplers	vacuum, coupling, rfq, linac	2505
	Y. W. Kang A. V. Aleksandrov, D. E. Anderson, M. S. Champion, M. T. Crofford, P. E. Gibson, T. W. Hardek, P. Ladd, M. P. McCarthy, D. Stout, A. V. Vassioutchenko ORNL, Oak Ridge, Tennessee
	Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U. S. Department of Energy. A RF power coupling system has been developed for future upgrade of input coupling of the RFQ in the SNS linac. The design employs two coaxial loop couplers for 402.5 MHz operation. Each loop is fed through a coaxial ceramic window that is connected to an output of a magic-T waveguide hybrid through a coaxial to waveguide transition. The coaxial loop couplers are designed, manufactured, and high power processed. Two couplers will be used in parallel to power the accelerating structure with up to total 800 kW peak power at 8% duty cycle. RF and mechanical properties of the couplers are discussed. Result of high power RF conditioning that is performed in the RF test facility of the SNS is presented.

WEPMS075	Development and Testing of High Power RF Vector Modulators	controls, impedance, simulation, linac	2508
	Y. W. Kang M. S. Champion, T. W. Hardek, S.-H. Kim, M. P. McCarthy, A. V. Vassioutchenko, J. L. Wilson ORNL, Oak Ridge, Tennessee
	Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U. S. Department of Energy. High power vector modulators can allow a fan-out RF power distribution system that can power many accelerating cavities from a single high-power klystron amplifier. The configuration enables independent control of amplitudes and phases of RF voltages at the cavities. A vector modulator employs either one or two hybrids with two fast phase shifters. Prototype high power RF vector modulators employing a hybrid and two fast ferrite phase shifters in coaxial TEM transmission lines for 402.5 MHz and 805 MHz are built and tested. RF properties of the design and result of high power testing are presented.

WEPMS079	Dynamic Fault Detection Chassis for the 1 MW High Voltage Converter Modulator System at the Spallation Neutron Source	controls, power-supply, monitoring, cathode	2514
	J. J. Mize, J. J. Mize ORNL, Oak Ridge, Tennessee
	Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U. S. Department of Energy. The high frequency switching megawatt-class High Voltage Converter Modulator (HVCM) developed by Los Alamos National Laboratory for the Oak Ridge National Laboratory's Spallation Neutron Source (SNS), is now in operation. One of the major problems with the modulator systems is shoot-thru conditions that can occur in an IGBTs H-bridge topology resulting in large fault currents and device failure in a few microseconds. The Dynamic Fault Detection Chassis (DFDC) is a fault monitoring system; it monitors transformer flux saturation using a window comparator and dV/dt events on the cathode voltage caused by any abnormality such as capacitor breakdown, transformer primary turns shorts, or dielectric breakdown between the transformer primary and secondary. If faults are detected, the DFDC will inhibit the IGBT gate drives and shut the system down, significantly reducing the possibility of a shoot-thru condition or other equipment damaging events. In this paper,we will present system integration considerations, performance characteristics of the DFDC, and discuss its ability to significantly reduce costly down time for the entire facility.

WEPMS082	PVC - An ILC RF Cryomodule Software Simulator	feedback, controls, simulation, superconducting-RF	2523
	J. K. Keung N. Lockyer TRIUMF, Vancouver S. Nagaitsev Fermilab, Batavia, Illinois F. M. Newcomer University of Pennsylvania, Philadelphia, Pennsylvania
	The Penn Virtual Cavity (PVC) simulator is a object oriented RF Cavity simulator with a user friendly Linux GUI, as well as a web interface. It is a tool to help understand the effects of each component in the RF system. It can simulate an International Linear Collider (ILC) cryomodule consisting of eight 9-cell cavities, together with its associated high voltage modulator, a klystron, and RF power distribution system. The uses range from experts designing LLRF control algorithms, to beginners learning about the general RF characteristics of the SRF cavities. PVC explores effects such as Lorentz Detuning, beam loading (with bunch to bunch fluctuations), 8/9pi modes, I/Q feedback and feedforward, cavity Q-drop, amplitude and phase jitter and ripples, as well as calibration errors. The current status of the PVC and the conclusions derived from the simulations will be reported, along with comparisons to the DESY-TTF cryomodules. http://einstein.hep.upenn.edu/~keungj/simulation.html

WEPMS083	A Low-Voltage Klystron for the ILC and ILC Testing Program	gun, simulation, cathode, linear-collider	2526
	N. Barov
	Funding: Work supported by the US Department of Energy. FAR-TECH, Inc. is developing and building a 36 kV, 830 kW klystron for the International Linear Collider (ILC) testing program. A variant of the tube can also be used to supply RF energy for a 2-3 meter section of ILC. The tube design is of the multiple-beam klystron (MBK) type, using ten beams with confined flow focusing. The design optimizes small tube size and low cost. The initial prototype will use an electromagnet, but the design allows for the eventual use of a permanent magnet solenoid. An efficiency of 65% is expected. We will present the design and status of the construction of the klystron and supporting systems.

WEPMS084	A Solid State Driven, Parasitic Oscillation Suppressed, 17 GHz High Gain TW Klystron for Stable Operation with High Gradient Linac Structures	linac, resonance, coupling, space-charge	2529
	J. Haimson B. A. Ishii, B. L. Mecklenburg, G. A. Stowell HRC, Santa Clara, California
	Funding: Work performed under the auspices of the U. S. Department of Energy SBIR Grant No. DE-FG02-04ER83973. The gain of a high power TW relativistic klystron can be increased substantially with the use of a varying phase velocity, large beam aperture, lengthened output structure, designed for asynchronous interaction to control space charge fields and provide near-adiabatic bunch compression during the power extraction process. While this technique enables the replacement of a pulsed vacuum tube driver system with a small, inexpensive solid state RF source, lengthening the output circuit increases the number (and reduces the separation) of the longitudinal mode resonances in the TM01 operating band. Thus, the probability of exciting parasitic oscillations is increased, especially when the klystron is operated into a mismatched load or a high Q structure. The prevention of such oscillations, even when in close proximity to the operating frequency, using a technique that is unaffected by the phase or amplitude of reflected signals is described; and test results are presented of a solid state driven, 76dB gain 17GHz TW relativistic klystron, recently installed in the linac test facility at the MIT Plasma Science and Fusion Center.

WEPMS093	Gridless IOT for Accelerator Applications	electron, cathode, controls, gun	2556
	C. Wilsen M. F. Kirshner, R. D. Kowalczyk L-3, Williamsport, Pennsylvania
	The klystron is the established microwave amplifier in accelerator driver applications, enjoying high power, gain and efficiency at saturation. Disadvantages are reduced efficiency in the linear regime and large size. Building on its success in the television broadcast market, the IOT provides a compact, high efficiency alternative for emerging accelerator applications. An integral component of the IOT input cavity is a control grid, which is positioned close to the cathode, not only to enhance the electric field for emission gating at the cathode surface, but also to limit the transit angle. The latter consideration constrains the operation of these devices to the lower frequency end of the microwave spectrum. Power is limited due to grid interception. Therefore, to fully exploit the benefits provided by density modulation, i.e., high efficiency and compact size, without the consequent frequency, power, and gain limitations, an emission gating method that does not rely on a closely spaced control grid is required. The solution is the Vector amplifier, a gridless IOT based on L-3's trajectory modulation technique* and an alternative compact, low cost RF source for the ILC. * M. F. Kirshner et al., "Apparatus and method for trajectory modulation of an electron beam," U. S. Provisional Patent Application 60/838,580, August 17, 2006. Cleared by DoD/OFOISR for public release under 07-S-0493 on January 22, 2007

THOBKI02	Marx Bank Technology for the International Linear Collider	power-supply, controls, linear-collider, collider	2590
	M. A. Kempkes F. O. Arntz, J. A. Casey, M. P.J. Gaudreau, I. Roth Diversified Technologies, Inc., Bedford, Massachusetts
	In August, 2004, the international science community formally backed the development of a superconducting linear accelerator named the International Linear Collider (ILC). It is expected that the accelerator will employ klystrons operating in the range of 110-135 kV, 120-166 A, and 1.5 ms pulsewidth. Due to the accelerator's long pulse length and high power, focusing on power supply and energy storage alternatives promises to yield significant reductions in acquisition costs. Diversified Technologies, Inc. (DTI) has developed a high power, solid-state Marx Bank topology, offering an optimal, silicon-efficient technology for the ILC modulators and power supplies. We estimate the Marx topology can deliver equivalent performance and yield acquisition cost savings of 25-50% versus presently proposed alternatives. In this paper DTI will describe the Marx based technology as it is applied to ILC power systems design, and review recent progress in the engineering of the prototype transmitter.

THOAAB02	Upgrade of the LENS Proton Linac: Commissioning and Results	target, proton, rfq, scattering	2611
	A. Bogdanov V. Anferov, M. Ball, D. V. Baxter, V. P. Derenchuk, A. V. Klyachko, T. Rinckel, P. E. Sokol, K. A. Solberg IUCF, Bloomington, Indiana
	Funding: The LENS project is supported by the NSF (grants DMR-0220560, DMR-0242300), the 21st Century Science and Technology fund of Indiana, Indiana University, and the Department of Defense A Low Energy Neutron Source at Indiana University provides cold neutrons for material research and neutron physics as well as neutrons in the MeV energy range for the neutron radiation effects studies. Neutrons are being produced by a 7 MeV proton beam incident on a Beryllium target. Presently, the Proton Delivery System has been routinely running at 7 MeV, 8 mA and with up to 0.5% duty factor. The RF system of the accelerator is currently being upgraded by replacing 350 kW 425 MHz 12 tube amplifiers with two Litton 5773 klystron RF tubes capable of running at 425 MHz and 1 MW. A new DTL section will be added to increase proton beam energy from 7 to 13 MeV. A 3 MeV RFQ and 13 MeV DTL will be powered by the klystrons. The expected output is 20 mA and 13 MeV of proton current at more than 1% duty factor. Other upgrades include construction of the 2nd beamline, which copies the 1st line, and a new target station for the production of cold neutrons. In this contribution we discuss the results of the commissioning of the new DTL accelerator, new RF system and 2nd beamline. The future plans will also be outlined.
	Slides

THYAB02	Commissioning of the J-PARC Linac	linac, rfq, acceleration, proton	2619
	K. Hasegawa
	The J-PARC (Japan Proton Accelerator Research Complex?is a joint project between the Japan Atomic Energy Agency (JAEA) and the High Energy Accelerator Research Organization (KEK) to construct and operate the high-intensity proton accelerator facility. The J-PARC comprises a 400 MeV linac, a 3 GeV rapid-cycling synchrotron (RCS), a 50 GeV main ring synchrotron (MR) and experimental facilities. The energy of the linac is reduced to 181 MeV for the time being, and it will be increased to 400 MeV in the near future. The 3 MeV RFQ, which is a front end of the linac, has been beam commissioned since November 2006, and we will continue to work on the rest of the linac such as a 50 MeV DTL and a 181 MeV Separated-type DTL. The results and status of the J-PARC linac beam commissioning will be presented.
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THIBKI01	RF Sources for the ILC	cathode, electron	2684
	A. Balkcum T. W. Habermann CPI, Palo Alto, California
	As currently envisioned, approximately 750 10 MW multiple beam klystrons (MBK) will be used to power the ILC accelerator. The critical role of the MBK to the successful operation of the machine makes it a key ILC component. The large quantity required coupled with its technical sophistication also makes it one of the more expensive individual components. CPI has manufactured a prototype MBK that was delivered to DESY in March 2005 for use on the Tesla Test Facility / European X-FEL projects. This klystron uses six low perveance, off-axis electron beams to produce the high powers required by both the ILC and X-FEL with high efficiency and the low cathode current density loading needed for extended operational life. The large scale production and costs for this klystron were examined as part of the US ILC industrialization cost study. Design for Assembly / Design for Manufacture techniques have been considered to make the klystron more easily manufacturable and less expensive. Many of these ideas are being used in the current design effort to produce a second MBK for DESY that will be horizontally oriented and appropriate for use in the actual X-FEL tunnel. A. Balkcum, et al. "Operation of a 1.3 GHz Multiple Beam Klystron," Proc. of 6th IVEC, pp. 505, Noordwijk (2005).
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THIBKI03	Klystron Development by TETD	electron, linac, proton, controls	2688
	K. Hayashi M. Irikura, Y. Mitsunaka, Y. Okubo, M. Sakamoto, H. Taoka, K. Tetsuka, H. Urakata TETD, Otawara M. Y. Miyake, Y. Yano Toshiba, Yokohama
	TETD (Toshiba Electron Tubes & Devices Co., LTD.) has been developing vacuum microwave devices such as klystrons, gyrotrons and input couplers in collaboration with some Japanese research institutes. This article describes recent development status of klystrons and input couplers for high-power RF accelerator systems including a 324-MHz and a 972-MHz klystrons for JARC, 1.3-GHz vertical and horizontal MBKs for DESY and a 1.3-GHz TTF-type input coupler for 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.
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THIBKI04	Developments of Long-pulse Klystron Modulator for KEK Super-conducting RF Test Facility	controls, superconducting-RF, simulation, power-supply	2691
	H. Mori M. Akemoto, S. Fukuda, H. Honma, H. Nakajima, T. Shidara KEK, Ibaraki K. Furuya Nichicon (Kusatsu) Corporation, Shiga
	NICHICON (KUSATSU) CORPORATION and KEK have developed a novel long-pulse klystron modulator for both of single-beam tube(136kVp100A) and multi-beam tube(120kVp140A). The main features are; - crowberless system with optimized IGBT snubber circuit, - compact and highly reliable Self-Healing capacitors, - HV & LV twin pulse transformers of laminated steel core for reduced tank volume. Detailed configuration and test results to be presented.
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THIBKI05	European Industry's Potential Capabilities for High Power RF Systems for the Future IlC	controls, site, target, electron	2693
	M. Wilcox
	Abstract to be supplied by speaker.
	Slides

THPMN026	C-band Linac in SCSS Prototype Accelerator of the Japanese X-FEL Project	linac, acceleration, power-supply, electron	2766
	T. Inagaki H. Baba, H. Matsumoto KEK, Ibaraki A. Miura Nihon Koshuha Co., Ltd., Yokohama S. Miura MHI, Hiroshima T. Shintake, K. Shirasawa RIKEN Spring-8 Harima, Hyogo
	Funding: RIKEN-JASRI Joint-Project for SPring-8 XFEL C-band (5712-MHz) linac is used as the main accelerator of the Japanese X-FEL facility in SPring-8. Since the C-band linac has high acceleration gradient, our 8-GeV accelerator is compact rather than a conventional S-band accelerator. The system consists of following components; two choke-mode-type 1.8-m accelerating structures, an rf pulse compressor (SLED), a 50-MW klystron, a 100-MW compact modulator, and an rf digital control system. We will use 60 to 70 units for the X-FEL accelerator. Since November 2005, we have operated two C-band units in the 250-MeV FEL prototype accelerator (SCSS). After rf conditioning, the accelerating gradient was achieved to 35-MV/m. We successfully accelerated the electron beam by this gradient of electrical field. In this presentation, we will report the detail of each component and its operation status of the SCSS prototype accelerator.

THPMN027	Status of C-band Accelerator Module in the KEKB Injector Linac	linac, acceleration, positron, electron	2769
	T. Kamitani T. Higo, M. Ikeda, K. Kakihara, N. Kudoh, S. Ohsawa, T. Sugimura, T. T. Takatomi, K. Yokoyama KEK, Ibaraki
	For future upgrade of the KEKB injector linac, components of C-band accelerator module have been developed since 2002. A prototype C-band accelerator module composed of a 50-MW klystron, an RF-pulse compressor and four 1-m long accelerating sections, has been constructed in the present S-band injector linac. It has been operated for 14 months. In a recent beam-acceleration study, it has achieved an energy gain of 151 MeV, which corresponds to an average acceleration field of 39 MV/m.

THPMN049	Current Status of Intense L-band Electron Accelerator for Irradiation Source	electron, power-supply, linac, controls	2826
	S. H. Kim M.-H. Cho, W. Namkung, H. R. Yang POSTECH, Pohang, Kyungbuk S. D. Jang, S. J. Kwon, J.-S. Oh, S. J. Park, Y. G. Son PAL, Pohang, Kyungbuk
	Funding: Work supported by KAPRA. An intense L-band electron accelerator is designed and under development for CESC (Cheorwon Electron-beam Service Center) irradiation applications. It is capable of producing 10-MeV electron beams with average 30 kW. For an RF source, a Thales klystron is used with 1.3 GHz, pulsed 25 MW, and average 60 kW. The accelerator column, fabricated by IHEP in China, is operated with 2π/3 mode traveling-wave under the fully-beam-loaded condition. The modulator was fabricated with inverter power supplies. The klystron was assembled to the klystron tank with pulse transformer. The high-voltage pulse test was conducted for the klystron tube. In this paper, we present design details of the accelerator and current status.

THPMS075	High Power Testing of a Fused Quartz-based Dielectric-loaded Accelerating Structure	plasma, impedance, vacuum, coupling	3157
	C.-J. Jing V. A. Dolgashev, S. G. Tantawi SLAC, Menlo Park, California W. Gai, R. Konecny, J. G. Power, Z. M. Yusof ANL, Argonne, Illinois S. H. Gold NRL, Washington, DC A. K. Kinkead LET
	We report on the most recent results from a series of high power tests being carried out on RF-driven dielectric-loaded accelerating (DLA) structures. The purpose of these tests is to determine the viability of the DLA as a traveling-wave accelerator and is a collaborative effort between Argonne National Laboratory (ANL), Naval Research Laboratory (NRL), and Stanford Linear Accelerator Center (SLAC). In this paper, we report on the recent high power tests of a fused quartz-based DLA structure that was carried out at incident powers of up to 12 MW at NRL and 37 MW at SLAC. We report experimental details of the RF conditioning process and make comparison of our multipactor model to the experiment, including tests of geometrical scaling laws and the time evolution of multipactor. Finally, we discuss future plans for the program including a planned test of new quartz-based DLA with a different geometry to both reach higher accelerating gradients and to continue the parametric study of multipactor.

THPAS063	Employment of Second Order Ruled Surfaces in Design of Sheet Beam Guns	gun, cathode, electron, focusing	3630
	A. Krasnykh
	Funding: Work supported by the U. S. Department of Energy under contract number DE-AC03-76SF00515 A novel 3D method of sheet beam (SB) gun design has recently been developed. Second order ruled surfaces (SORS) to define the geometry of the gun electrodes. The gun design process is made simpler if SORS are derived from simple analytical formulas. The coefficients of the mathematical expression are parameters that set the gun optic. A proposed design method is discussed and illustrated.

THPAS079	A Copper 3.9 GHz TM110 Cavity for Emittance Exchange	polarization, coupling, emittance, vacuum	3663
	T. W. Koeth L. Bellantoni, D. A. Edwards, H. Edwards, R. P. Fliller Fermilab, Batavia, Illinois
	Funding: Work supported by Universities Research Association Inc. under contract DE-AC02-76CH00300 with the U. S. DOE. An experiment is being constructed at Fermilab's A0 Photoinjector to exchange longitudinal and transverse beam emittances. The exchange is preformed by an optics channel consisting of two dogleg bend sections with a transverse deflecting mode cavity between them. In this paper we discuss the construction of the TM110 Mode Cavity. The cavity, based on a superconducting design will be constructed of copper. In addition, the cavity will be cooled with liquid nitrogen to fit within power and mode spacing requirements. The TM110 cavity operating requirements are presented as will the detail of the design, construction, tuning, and commissioning of the TM110 cavity.

FRXC01	SNS RF System Performance and Operation	linac, controls, cathode, monitoring	3792
	M. S. Champion
	The Spallation Neutron Source (SNS) Linac and Accumulator Ring utilize 100 Radio-Frequency (RF) systems for acceleration and bunching of the proton beam. Several different types of gridded tubes and klystrons are operated at 1, 2, 402.5 and 805 MHz, at power levels ranging from a few kilowatts to several megawatts to drive several types of accelerating cavities, both normal- and super-conducting. The RF systems are standardized, especially in the Linac, to ease operation and maintenance. Phase and amplitude control is achieved with a digital low-level RF control system. The RF systems operate reliably and support production of a high-quality low-loss proton beam. Various modifications and upgrades have been made or are in progress to enhance system reliability and performance. Planning is well underway for a power upgrade that will require an additional 36 RF systems.
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FROAC06	Survey of LLRF Development for the ILC	controls, feedback, linac, linear-collider	3810
	J. Branlard B. Chase Fermilab, Batavia, Illinois S. Michizono KEK, Ibaraki S. Simrock DESY, Hamburg
	Funding: FRA The key to a successful LLRF design for the International Linear Collider (ILC) relies on a combined effort from the different laboratories involved in this global project. This paper covers the ILC LLRF design progress both long term and for current test facilities around the world. Much of the focus is towards the ILC Test Area and on inter-laboratories collaborations. The SIMCON controller board, originally developed at DESY has been successfully used at FNAL to control the superconducting capture cavity I and II. A joined effort is also underway to modify its hardware to improve its noise performance and upgrading the firmware to achieve a higher intermediate frequency operation. In parallel, several simulation models (U-Penn, FNAL) have been developed in addition to the Simulink based model from DESY. The motivation is to investigate such issues as variable gradients, low beam conditions and bunch compression. Finally, an active exchange of knowledge and expertise continues to occur during collaboration meetings and through mutual participation in accelerator tests and commissioning (Dec06/Jan07 at DESY).
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FRYC01	ILC RF System R&D	simulation, electron, focusing, gun	3813
	C. Adolphsen
	Funding: Work Supported by DOE Contract DE-AC02-76F00515 The ILC Linac Group at SLAC is actively pursuing a broad range of R&D to improve the reliability and reduce the cost of the L-band (1.3 GHz) rf system and normal-conducting accelerators. Current activities include the development of a Marx-style modulator and a 10 MW sheet-beam klystron, operation of an L-band (1.3 GHz) rf source using an SNS HVCM modulator and commercial klystron, construction of an rf distribution system with adjustable power tap-offs and custom hybrids, tests of cavity coupler components to understand rf processing limitations, simulation of multipacting in the couplers, optimization of the cavity fill parameters for operation with a large spread in sustainable cavity gradients and operation of a 5-cell prototype positron capture cavity. This paper surveys the results from the past year and reviews L-band R&D at other labs, in particular, that at DESY for the XFEL project.
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FROBC02	RF Structures for Linac4	linac, coupling, alignment, quadrupole	3821
	F. Gerigk N. Alharbi, M. Pasini, S. Ramberger, M. Vretenar, R. Wegner CERN, Geneva
	Linac4 is proposed to replace the existing proton linac at CERN (Linac2). Using an increased injection energy of 160 MeV instead of 50 MeV Linac4 is expected to double the beam intensity in the PS Booster and will thus be the first step towards higher brightness beams in the LHC. In this paper we re-assess the choice of RF structures for Linac4. Different accelerating structures for different energy ranges are compared in terms of RF efficiency, ease of construction and alignment, necessary infrastructure, and cost. Eventually we present the final choice of structures for Linac4.
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FRPMN083	RF Feed-Forward Control Experiments for the 50 MeV Linear Accelerator at TLS	controls, linac, booster, synchrotron	4258
	K. H. Hu K. T. Hsu, J.-Y. Hwang, D. Lee, K.-K. Lin, C. Y. Wu NSRRC, Hsinchu
	Performance of an electron linear accelerator is very important for synchrotron light source application. Its performance will decide the reproducibility of filling pattern in the booster synchrotron. The filling pattern of the booster synchrotron will affect filling pattern control of the storage ring. The RF feed-forward control can improve performance of linear accelerator deistically. Design consideration and details of the implementation will be summary in this report.

FRPMS041	A Direct Electron Beam Energy Spread Measurement System for Beam Instability and FEL Research	electron, wiggler, storage-ring, radiation	4045
	S. Huang, S. Huang PKU/IHIP, Beijing J. Li, Y. K. Wu FEL/Duke University, Durham, North Carolina
	Funding: Supported by US AFOSR MFEL grant #FA9550-04-01-0086. One of critical beam parameters for the storage ring based light sources is the energy spread of the electron beam. An accurate measurement of the energy spread remains a challenge. It is well known that the electrons with different energies can degrade the spontaneous emission spectrum of a two-wiggler system in an optical-klystron configuration. The reduced modulation in the spectrum can be used to determine the energy spread of the beam. This paper describes our newly developed energy spread measurement system employing a scanning spectrometer and a fast CCD. A fast CCD with a burst mode of operation is used so that dynamical changes of the energy spread from tens of microseconds to tens of milliseconds can be measured. This system will be used in the beam instability research and free-electron laser research. Together with compact wigglers, such a system can be developed as a dedicated beam diagnostic for storage rings and linacs.

FRPMS045	Non-Destructive Single Shot Bunch Length Measurements for the CLIC Test Facility 3	electron, pick-up, linac, radiation	4069
	A. E. Dabrowski H.-H. Braun, R. Corsini, S. Doebert, T. Lefevre, F. Tecker, P. Urschutz CERN, Geneva M. Velasco NU, Evanston
	Funding: DOE A non-destructive bunch length detector has been installed in the CLIC Test Facility (CTF3). Using a series of down-converting mixing stages and filters, the detector analyzes the power spectrum of the electromagnetic field picked-up by a single waveguide. This detector evolved from an earlier system which was regularly used for bunch length measurements in CTF2. Major improvements are increase of frequency reach from 90 GHz to 170 GHz, allowing for sub-pico second sensitivity, and single shot measurement capability using FFT analysis from large bandwidth waveform digitisers. The results of the commissioning of the detector in 2006 are presented.