LINAC 2004 - Classification:Technology, Components, Subsystems/RF Power, Pulsed Power, Components

Technology, Components, Subsystems

RF Power, Pulsed Power, Components

Paper	Title	Page
TUP80	A Long-Pulse Modulator for the TESLA Test Facility (TTF)	459
	W. Kaesler PPT, Dortmund
	The long-pulse (1.6 ms) klystron modulator for TTF is a hardtube pulser using a Bouncer-circuit for droop compensation. It is built up with new advanced components representing industrial standards. The on-/off switch is a rugged 12 kV IGCT-stack with a fast 4kA turn-off capability. The 100 kJ storage capacitor bank contains only three capacitors with self-healing, segmented PP-foil technology. A new 100 kA solid-state switch based on light triggered thyristors (LTT) replaced the standard ignitrons as crowbar switches. The 300 kW high voltage power supply is based on modern switched mode technology.
TH201	IOT RF Power Sources for Pulsed and CW Linacs	574
	H.P. Bohlen CPI, Palo Alto, California Y. Li, R.N. Tornoe CPI/EIMAC, San Carlos, California
	For many years, klystrons have been the preferred RF power amplifiers for both pulsed and CW linacs at UHF and higher frequencies. Their properties have earned them that position. But in recent years in UHF terrestrial television transmitters the earlier predominant klystron has been replaced the Inductive Output Tube (IOT) because the IOT provides higher efficiency and, due to its excellent linearity, can handle the simultaneous amplification of both the vision and the sound signal. Its robustness and life expectancy equals that of a klystron, and it more than compensates its lower gain by a lower price and a smaller size. For linac operation, derivates of UHF TV IOTs, capable of up to 80 kW CW output power, are already available and operating. In L-Band, they are presently joined by recently developed 15 to 30 kW CW IOTs. HOM-IOTs are expected to extend the CW range in UHF to 1 MW and beyond. Pulsed operation of an IOT can be achieved without a high-voltage modulator. Since the beam current is grid-controlled it is sufficient to pulse the drive power.
	Transparencies
THP28	Multi-Mode SLED-II Pulse Compressors	660
	S. Kuzikov, Y.Y. Danilov, G. G. Denisov, V. G. Paveliev, D. Yu. Shegol'kov, A. A. Vikharev IAP, Nizhniy Novgorod I. Syratchev CERN, Geneva
	Compact SLED-II pulse compressors are considered. The primary idea of S. Kazakov to use a set of the cylindrical multi-mode cavities, to be free of high-Q resonances around the 11.4 GHz, is analyzed. This idea is developed, in order to provide more delaying time per miter of the line. Another idea to provide compactness is to avoid two-channel scheme with 3 dB coupler usually used for SLED-II pulse compressors. A reflectionless delay line is built in this case, using coupling in a form of the non-symmetrical mode converter. SLED-II pulse compressors of higher frequency bands also are considered. It is suggested to shape these compressors on a base of the multi-mirror transmission lines. The operating mode in this case is a Gaussian wavebeam traveling between mirrors. Various configurations of the mirrors are compared from the point of view of maximum of compactness at the given pulse duration. The results of the preliminary experiments at low power level are discussed.
	Transparencies
THP39	Operation of a 1.3 GHz, 10 MW Multiple Beam Klystron	693
	H.P. Bohlen, A. Balkcum, M. Cattelino, L. Cox, M. Cusick, S. Forrest, F. Friedlander, A. Staprans, E. Wright, L. Zitelli CPI, Palo Alto, California K. Eppley SAIC, Boston
	Results will be reported for a 1.3 GHz, 10 MW multiple beam klystron that is being developed for the TESLA linear accelerator facility. The design parameters for the device are 10 MW peak RF output power with 150 kW average power, 1.5 ms pulse length, 65% efficiency, 50 dB gain, and 2.0 A/cm² maximum cathode loading. Initial testing of the device has validated the basic design approach. Six 120 kV electron beams of measurably identical currents of 22.9 A each have been successfully propagated through the klystron circuit with 99.5% DC beam transmission at full operating video duty and with 98.5% saturated RF transmission. A peak power of 10 MW at 1.3 GHz with 60% efficiency and 49 dB of gain has been measured.
THP41	Development of High RF Power Delivery System for 1300 MHz Superconducting Cavities of Cornell ERL Injector	694
	S.A. Belomestnykh, M. Liepe, V. Medjidzade, H. Padamsee, V. Veshcherevich LEPP, Ithaca, New York N.P. Sobenin MEPhI, Moscow
	Development of a 150 kW CW RF power delivery system for 1300 MHz superconducting cavities is under way at Cornell University in collaboration with MEPhI. The system is based on a twin-coupler consisting of two identical coaxial antenna-type couplers derived from the TTF-3 input coupler design. Because the average power is much higher than in the TTF-3 coupler, the required coupling is stronger and we wanted to avoid multipacting phenomena, major changes were made to the prototype design. Presented coupler has completely redesigned cold part and significantly improved cooling of warm bellows. The results of thermal and mechanical stress calculations are reported. The magnitudes and phases of RF fields applied to each side of the twin-coupler must be very close to each other. This imposes very strict requirements upon a power dividing system. These requirements and proposed layout of a system satisfying them are discussed.
THP42	NLC Hybrid Solid State Induction Modulator	697
	R.L. Cassel, M. Nguyen, G.C. Pappas, J.E. deLamare SLAC, Stanford C. Brooksby, E. Cook, J. Sullivan LLNL, Livermore
	The Next Linear Collider accelerator proposal at SLAC requires a high efficiency, highly reliable, and low cost pulsed power modulator to drive the X-band klystrons. The original NLC envisions a solid state induction modulator design to drive up to 8 klystrons to 500 kV for 3 μs at 120 PPS with one modulator delivering greater than 1,000 MW pulse, at 500 kW average. A change in RF compression techniques resulted in only two klystrons needed pulsing per modulator at a reduced pulse width of 1.6 μsec or approximately 250 MW of the pulsed power and 80 kW of average powers. A prototype Design for Manufacturability (DFM) 8-pack modulator was under construction at the time of the change, so a redirection of modulator design was in order. To utilities the equipment which had already be fabricated, a hybrid modulator was designed and constructed using the DFM induction modulator parts and a conventional pulse transformer. The construction and performance of this hybrid two klystron Induction modulator will be discussed. In addition the next generation DFM induction modulator utilizing a ten turn secondary and fractional turn primary transformer well be presented.
THP43	Reduction of RF Power Loss Caused by Skin Effect	700
	Y. Iwashita Kyoto ICR, Kyoto
	RF current flows only on a metal surface with very thin skin depth, which decreases with RF frequency. Thus the surface resistance increases with the frequency. Because the skin depth also decreases when the metal conductivity increases, the improvement of the conductivity does not contribute much; it is only an inverse proportion to the square root of the conductivity. Recently, it is shown that such a power loss can be reduced on a dielectric cavity with thin conductor layers on the surface, where the layers are thinner than the skin depth. Some possibilities to implement the idea and to extend the application to general cavities and transmission lines will be discussed.
THP44	The Design and Performance of the Spallation Neutron Source Low-Level RF Control System	703
	M. Champion, M. Crofford, K. Kasemir, H. Ma, C. Piller ORNL/SNS, Oak Ridge, Tennessee L. Doolittle, C. Lionberger, M. Monroy, A. Ratti LBNL, Berkeley, California J. Power, H. Shoee LANL, Los Alamos, New Mexico
	The Spallation Neutron Source linear accelerator low-level RF control system has been developed within a collaboration of Lawrence Berkeley, Los Alamos, and Oak Ridge national laboratories. Three distinct generations of the system, described in a previous publication [1], have been used to support beam commissioning at Oak Ridge. The third generation system went into production in early 2004, with installation in the coupled-cavity and superconducting linacs to span the remainder of the year. The final design of this system will be presented along with results of performance measurements. [1] M. Champion, et al, "The Spallation Neutron Source Accelerator Low Level RF Control System", Proceedings of the PAC2003 Conference, Portland, Oregon.
THP45	The Toshiba E3736 Multi Beam Klystron	706
	A. Yano, S. Miyake TETD, Saitama Y.H. Chin KEK, Ibaraki S.Y. Kazakov IHEP Protvino, Protvino, Moscow Region A.V. Larionov, V.E. Teryaev BINP SB RAS, Protvino, Moscow Region
	A 10 MW, L-band multi beam klystron (MBK) for TESLA linear collider and TESLA XFEL has been under development at Toshiba Electron Tubes & Devices Co., Ltd. (TETD) in collaboration with KEK. The TESLA requires pulsed klystrons capable of 10 MW output power at 1300 MHz with 1.5 ms pulse length and a repetition rate of 10 pps. The MBK with 6 low-perveance beams in parallel in the klystron enables us to operate at lower cathode voltage with higher efficiency. The design work has been accomplished and the fabrication is under way. We are going to start conditioning and testing of prototype #0 in the beginning of June 2004. The design overview and the initial test results at the factory will be presented.
THP46	Cable Insulation Breakdowns in the Modulator with a Switch Mode High Voltage Power Supply	709
	A. Cours ANL, Argonne, Illinois
	The Advanced Photon Source modulators are PFN-type pulsers with 40 kV switch mode charging power supplies (PSs). The PS and the PFN are connected to each other by 18 feet of high-voltage (HV) cable. Another HV cable connects two separate parts of the PFN. The cables are standard 75 kV x-ray cables. All four cable connectors were designed by the PS manufacturer. Both cables were operating at the same voltage level (about 35 kV). The PS’s output connector has never failed during five years of operation. One of the other three connectors failed approximately five times more often than the others. In order to resolve the failure problem, a transient analysis was performed for all connectors. It was found that transient voltage in the connector that failed most often was subjected to more high-frequency, high-amplitude AC components than the other three connectors. It was thought that these components caused partial discharge in the connector insulation and led to the insulation breakdown. Modification of the PFN eliminated one HV cable and significantly reduced the AC components during the pulse. A connector with higher partial discharge inception voltage was chosen as a replacement.
THP47	The RF-System for A High Current RFQ at IHEP	712
	Z. Zhang, J. Li, J. Qiao, X. Xu IHEP Beijing, Beijing
	The R&D of a high current proton RFQ is one of the most important research tasks of the Accelerator Driven Sub-critical system (ADS) basic research project. In preliminary research phase, the 352.2 MHz RF system will be operated in pulse mode. CERN kindly provided IHEP with some RF equipment. Because the given RF system was used for CW operation at CERN before, to apply them to our pulse mode operation, some modifications and improvements are necessary. We made some indispensable assemblies, and also did some tests and commissioning of every sub-system. At present, the initial high power conditioning of the klystron is finished, and output power can reach nominal value. A description of RF power system is given, in particularly, the performance of HV power supply, thyratron crowbar and capacitors, hard tube modulator and its control electronics, and klystron power conditioning are presented.
	Transparencies
THP48	A High-Resolution S-band Down-Converting Digital Phase Detector for SASE FEL Use	715
	A.E. Grelick, N.D. Arnold ANL/APS, Argonne, Illinois J. Carwardine, N. Dimonte, A. Nassiri, T. Smith ANL, Argonne, Illinois
	Each of the rf phase detectors in the Advanced Photon Source linac consists of a module that down converts from S-band to 20 MHz followed by an analog I/Q detector. Phase is calculated from one digitized sample per pulse each of I and Q. The resulting data has excellent long-term stability but is noisy enough so that a number of samples must be averaged to get a usable reading. The more recent requirement to support a SASE FEL has presented the need to accurately resolve the relative phase of a single pulse. Replacing analog detection with digital sampling and replacing internal intermediate frequency reference oscillators with a lower noise external oscillator were used to control the two largest components of noise. The implementation of a central, ultralow noise reference oscillator and a distribution system capable of maintaining the low phase noise is described, together with the results obtained to date. The principal remaining technical issue is determining the processing power required as a function of measurement channels per processor, measured pulse repetition rate, intrapulse data bandwidth, and digital filter characteristics. The options and tradeoffs involved and the present status are discussed.
THP49	The RF-Station Interlock for the European X-ray laser	718
	T. Grevsmühl, S. Choroba, Ph. Duval, O. Hensler, J. Kahl, F.-R. Kaiser, A. Kretzschmann, K. Rehlich, U. Schwendicke, S. Simrock, S. Weisse DESY, Hamburg H. Leich, RW. Wenndorff DESY Zeuthen, Zeuthen
	The RF-station interlock for the European X-ray laser will be based on a 19"- 3U crate incorporating a controller with the 32-bit RISC NIOS-processor (ALTERA). The main task of the interlock system is to prevent any damage from the components of the RF station and connected cavities. The interlock system must also guarantee a maximum time of operation of the RF stations which implies the implementation of self diagnostics and repair strategies on a module basis. Additional tasks are: collection and temporary storage of status information of the individual channels of the interlock system, transfer of this information to the control system, slow control functions (e.g. HV setting and monitoring) and control of inputs and outputs from and to other subsystems. In this paper we present the implementation using an ALTERA-FPGA running a 32-bit RISC NIOS-processor. Connection to the accelerator main control is provided by Ethernet using BSD-style socket routines based on ALTERA's plugs-library. The layout of the system is presented and first hardware components are shown.
THP50	The CEBAF RF Separator System Upgrade	721
	C. Hovater, M. Augustine, A. Guerra, R. Nelson, R.A. Terrel, M. Wissmann TJNAF, Newport News, Virginia
	The CEBAF accelerator uses RF deflecting cavities operating at the third sub-harmonic (499 MHz) of the accelerating frequency (1497 MHz) to “kick” the electron beam to the experimental halls. The cavities operate in a TEM dipole mode incorporating mode enhancing rods to increase the cavity’s transverse shunt impedance. As the accelerators energy has increased from 4 GeV to 6 GeV the RF system, specifically the 1 kW solid state amplifiers, have become problematic, operating in saturation because of the increased beam energy demands. Two years ago we began a study to look into replacement for the RF amplifiers and decided to use a commercial broadcast Inductive Output Tube (IOT) capable of 30 kW. The new RF system uses one IOT amplifier on multiple cavities as opposed to one amplifier per cavity originally. In addition the new RF system supports the proposed 12 GeV energy upgrade to CEBAF. Currently we are halfway through the upgrade with two IOTs in operation and two more to be installed. This paper reports on the new RF system and the IOT performance.
THP51	Tuning of External Q And Phase for The Cavities of A Superconducting Linear Accelerator	724
	V.V. Katalev, S. Choroba DESY, Hamburg
	The RF power required for a certain gradient of a superconducting cavity depends on the beam current and coupling between the cavity and waveguide. The coupling with the cavity may be changed by variation of Qext. Different devices can be used to adjust Qext or phase. In this paper three stub and E-H tuners are compared and their usability for the RF power distribution system for the superconducting accelerator of the European Xray laser and the TESLA linear collider is considered. The tuners were analyzed by using the scattering matrix. Advantages and limitations of the devices are presented.
THP52	RF Reference Distribution System for the J-PARC Linac	727
	T. Kobayashi, E. Chishiro JAERI, Ibaraki-ken S. Anami, S. Michizono, S. Yamaguchi KEK, Ibaraki
	J-PARC (Japan Proton Accelerator Complex) linac, which is 300 m long, consists of 324 MHz accelerating section of the upstream and 972 MHz section (as future plan) of the downstream. In the klystron gallery, totally about 50 RF source control stations will stand for the klystrons and solid-state amplifiers. The error of the accelerating field must be within ±1° in phase and ±1% in amplitude. Thus, the high phase stability is required to the RF reference for all of the low-level RF control systems and the beam monitor systems. This paper presents a final design of the RF reference distribution system for this linac. The RF reference (12 MHz) is distributed to all stations optically. Low-jitter E/O and O/E with temperature stabilizers are developed. The reference is optically amplified and divided into 14 transmission lines, and is delivered through PSOF (the phase-stabilized optical fiber), the temperature of which is stabilized by cooling water. Each of the transmitted signals is divided more into 4 signals by an optical coupler. Our objective for the phase stability of the reference aims at <±0.3° at a 972 MHz frequency.
THP53	Quasi-Optical Components for Future Linear Colliders	730
	S. Kuzikov, G. G. Denisov, M. Yu. Shmelyov IAP, Nizhniy Novgorod J.L. Hirshfield Omega-P, Inc., New Haven, Connecticut
	This paper presents a concept of the quasi-optical RF system for future Ka-band electron-positron linear collider. According to this concept two RF feeding systems are considered: a Delay Line Distribution System (DLDS) and a pulse compressor based on the multi-mirror traveling-wave resonator. The DLDS is based on oversized waveguides. In such waveguides the so-called image multiplication phenomena are used for power launching, extracting, combining, and splitting of waves. Recent low power tests of mode launchers and other DLDS components are discussed. The 34 GHz pulse compressors, based on three and four-mirror resonators, are considered. The tests of the prototypes at a low power level under different modulation methods are discussed. The simulations and tests of mode converters, miter bends, RF loads, and other components, to be necessary for both compression systems, also are resulted.
THP54	Moscow Meson Factory DTL RF System Upgrade	733
	A.I. Kvasha RAS/INR, Moscow
	The last paper devoted to description of the first part (DTL) RF system of Moscow Meson Factory upgrade was published in the Proceedings of PAC95 Conference in Dallas. Since then some new works directed at improvement of reliability and efficiency of the RF system were carried out. Among them there are a new powerful pulse triode “Katran” installed in the output RF power amplifiers (PA) of three channels, modifications of the anode modulator control circuit and crow-bar system, a new additional RF channel for RF supply of RFQ and some alterations in placing of the anode modulator equipment decreasing a level of interference’s at crow-bar circuits. Some new checked at MMF RF channels ideas concerning of PA tuning are of interest for people working in this sphere of activity.
THP55	Electromagnetic Design of New RF Power Couplers for the S-DALINAC	736
	M. Kunze, M. Brunken, H.-D. Gräf, W.F.O. Müller, A. Richter, T. Weiland TU Darmstadt, Darmstadt
	New rf power couplers for the Superconducting Darmstadt Linear Accelerator (S-DALINAC) injector have to be designed to transfer rf power of up to 2 kW to the electron beam. This allows injector operation at beam currents from 0.15 mA to 0.2 mA and electron energies up to 14 MeV. The new couplers should possibly provide a external Q of 5·10⁶. The transverse kick should be as small as possible. The asymmetric field distribution of the couplers causes emittance growth of the electron beam and therefore the transverse kick has to be minimized. Electromagnetic simulations are applied to investigate different coupler designs and to localize possible problems at an early stage. Cavity external Q and transverse kick can be calculated from 3D electromagnetic eigenmode solutions. The present coaxial-coaxial input couplers at the S-DALINAC are limited to power operation below 500 W under full reflection. In order to reach power operation up to 2 kW a realizations of a low-kick waveguide coupler for the S-DALINAC injector is presented, namely a twin-waveguide coupler.
	Transparencies
THP56	Control of the Low Level RF System for J-Parc Linac	739
	S. Michizono, S. Anami, E. Kadokura, S. Yamaguchi KEK, Ibaraki E. Chishiro, T. Kobayashi, .H. Suzuki JAERI, Ibaraki-ken
	A low level RF (LLRF) system for J-Parc linac generates RF and clock signals, drives a klystron, and stabilizes accelerating fields in the cavities. The LLRF system is controlled by two units: a programmable logic controller (PLC) and a compact PCI (cPCI) controller. Functions of the PLC are ON/OFF and UP/DOWN controls, and STATUS and ANALOG monitors. The PLC is locally operated by a touch panel, and remotely operated by an EPICS IOC with Ethernet communication. The cPCI controller is for RF feedback and feed-forward controls, including a cavity tuner control, and then, locally and remotely operated by communication with the PLC. On the other hand, RF waveform data, which are stored in the memory of DSP and CPU boards in the cPCI, are directory transmitted to an EPICS OPI by a request from EPICS.
THP57	Digital Feedback System for J-Parc Linac RF Source	742
	S. Michizono, S. Anami, S. Yamaguchi KEK, Ibaraki T. Kobayashi J-PARC, Ibaraki-ken
	At the proton linac of J-Parc (Japan Proton Accelerator Research Complex), an accelerating electric field stability of ±1% in amplitude and ±1° in phase is required for the RF system. In order to accomplish these requirements, a digital feedback system is adopted for flexibility of the feedback (FB) and feed forward (FF) algorism implementation. FPGAs are used for the real-time FB system. A DSP board is also utilized for data processing and communication between FPGAs and a crate control CPU (Host). The system was examined with the DTL cavity and it satisfies the stability specification. In this report, the digital rf system is described and operational stability is also summarized.
THP58	Development of C-band High-Power Mix-Mode RF Window	745
	S. Michizono, S. Fukuda, T. Matsumoto, K. Nakao, T. Takenaka KEK, Ibaraki K. Yoshida MELCO, Hyogo
	High power c-band (5712 MHz) rf system (40 MW, 2 μs, 50 Hz) is under consideration for the electron-linac upgrade aimed for the super KEKB project. An rf window, which isolates the vacuum and pass the rf power, is one of the most important components for the rf system. The window consists of a ceramic disk and a pill-box housing. The mix-mode rf window is designed so as to decrease the electric field on the periphery of the ceramic disk. A resonant ring is assembled in order to examine the high-power transmission test. The window was tested up to the transmission power of 160 MW. The rf losses are also measured during the rf operation.
THP59	Low Level RF Including a Sophisticated Phase Control System for CTF3	748
	J. Mourier, R. Bossart, J. Nonglaton, I. Syratchev, L. Tanner CERN, Geneva
	CTF3 (CLIC Test Facility 3), currently under construction at CERN, is a test facility designed to demonstrate the key feasibility issues of the CLIC (Compact LInear Collider) two-beam scheme. When completed, this facility will consist of a 150 MeV linac followed by two rings for bunch-interleaving, and a test stand where 30 GHz power will be generated. In this paper, the work that has been carried out on the linac’s low power RF system is described. This includes, in particular, a sophisticated phase control system for the RF pulse compressor to produce a flat-top rectangular pulse over 1.4 μs.
THP60	High-Power RF Distribution System for the 8-Pack Project	751
	C.D. Nantista SLAC/ARDB, Menlo Park, California D.P. Atkinson LLNL, Livermore J.Q. Chan SLAC/NLC, Menlo Park, California S.Y. Kazakov KEK, Ibaraki D.C. Schultz SLAC, Menlo Park, California S.G. Tantawi SLAC/ARDA, Menlo Park, California
	The 8-Pack Project at SLAC is a prototype rf system whose goal is to demonstrate the high-power X-band technology developed in the NLC/GLC program. In its first phase, it has reliably produced a 400 ns rf pulse of over 500 MW using a solid-state modulator, four 11.424 GHz klystrons and a dual-moded SLED-II pulse compressor [1]. In Phase 2, the output power of our system has been delivered into the bunker of the NLCTA (Next Linear Collider Test Accelerator) and divided between several accelerating structures, first four and finally eight, for beam acceleration. We describe here the design, cold-test measurements, and processing of this power distribution system. Due to the high power levels and the need for efficiency, overmoded waveguide and components are used. For power transport, the TE 01 mode is used in 7.44 cm and 4.064 cm diameter circular waveguide. Only near the structures is standard WR90 rectangular waveguide employed. Components used to manipulate the rf power include transitional tapers, mode converters, overmoded bends, fractional directional couplers, and hybrids. [1] S. Tantawi, et al., “Status of High-Power Tests of the Dual-Mode SLED-II System for an X-Band Linear Collider,” FR202, these proceedings.
THP61	SKIP - A Pulse Compressor for SuperKEKB	754
	T. Sugimura, M. Ikeda, K. Kakihara, T. Kamitani, S. Ohsawa, K. Yokoyama KEK, Ibaraki
	An upgrade of KEKB injector linac is planned. A main purpose of this upgrade is to increase injection energy of positrons from 3.5 GeV to 8.0 GeV for the SuperKEKB project. By a limitation of land area, our choice is to double an acceleration field utilizing a C-band accelerator structures instead of present S-band structures. Last year we developed C-band components such as accelerator structure, dummy load, 3 dB hybrid coupler, RF window, sub booster, modulator system, and so on. These components were assembled at a test stand and processed. This accelerator unit was installed in the beam line of injector linac and has been under operation. This summer we will install an RF pulse compressor system to the C-band accelerator unit. This paper reports the status of development of the RF pulse compressor system.
THP64	Waveguide Stub Tuner Analysis for CEBAF Application	757
	H. Wang Jefferson Lab, Newport News, Virginia M. Tiefenback TJNAF, Newport News, Virginia
	Three-stub WR650 waveguide tuners have been used on the CEBAF superconducting cavities for two changes on the external Qs: increasing the Q from 6·10⁶ to 8·10⁶ on 5-cell cavities to reduce the klystron power at operation gradients and decreasing the Q from 2·10⁷ to 8·10⁶ on 7-cell cavities to ease the control system handling the Lorenz Force detuning. To understand the reactive tuning effects in the machine operations with beam current and mechanical tuning, a network analysis model was developed. The S parameters of the stub tuner were simulated by MAFIA and measured on the bench. We used this stub tuner model to study tuning range, sensitivity, frequency pulling as well as cold waveguide and window heating problems. Detailed experimental results will be compared against this model. Pros and cons of this stub tuner application will be summarized.
FR202	Status of High-Power Tests of Dual Mode SLED-II System for an X-Band Linear Collider	852
	S.G. Tantawi SLAC/ARDA, Menlo Park, California V.A. Dolgashev, C.D. Nantista SLAC/ARDB, Menlo Park, California
	We have produced 400 ns rf pulses of greater than 500 MW at 11.424 GHz with an rf system designed to demonstrate technology capable of powering a TeV scale electron-positron linear collider. Power is produced by four 50 MW X-band klystrons run off a common 400 kV solid-state modulator. We present the layout of our system, which includes a dual-moded transmission waveguide system and a dual-moded resonant-line (SLED-II) pulse compression system. Dual-moding of the transmission lines allows power to be directed through a pulse compression path or a bypass path; dual-moding in the pulse compressor allows the delay lines to be about half as long as they otherwise would need to be. We describe the design and performance of various components, including hybrids, directional couplers, power dividers, tapers, mode converters, and loads. These components are mostly overmoded to allow for greater power handling. We also present data on the processing and operation of this system. The power from that system is transported to feed a set accelerator structure. We will present the design and the high power testing data for the overmoded transfer line and the distribution network.
	Transparencies