Paper | Title | Page |
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TU204 | Design and Performance of L-Band and S-Band Multi-Beam Klystrons | 369 |
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In the last couple of years, great achievements have been realized through world-wide developments of multi-beam klystrons (MBK) in the L-band and S-band. These MBKs are developed by industries such as Toshiba, Thales and CPI for the European X-FEL project or at the Naval Research Lab or by the Chinese Academy of Sciences for high-power, low-voltage radar systems. Some of them are already in operation at full specifications and are commercially available. The MBKs are superior to conventional single-beam klystrons through their ability to increase the output power dramatically while the operating voltage can be kept at a similar level. This talk will review the performances of these multi-beam klystrons, their design features, and future development plans. |
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THP048 | RF Power Amplifiers for the SPIRAL2 Driver: Requirements and Status | 897 |
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The SPIRAL2 project uses an RFQ, normal conducting rebunchers and a superconducting linac to accelerate high intensity beams of protons, deuterons and heavier ions. All cavities work at 88 MHz, are independently phased and powered by amplifiers whose power ranges from a few kW to 250 kW. The paper describes the amplifier requirements, the proposed solutions and their status. |
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THP054 | Status of RF Sources in Super-Conducting RF Test Facility (STF) at KEK | 909 |
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Phase 0.5 and Phase 1.0 of the Superconducting RF Test Facility (STF) have been developed since 2005 in KEK. We have completed the two rf-sources and they have been used for the evaluation for the components of power distribution system (PDS) and couplers which were installed in the 5m-cryomodules. We have developed some rf components which is used in the power distribution system(PDS). Phase 1.0 have been conducted now and we attempt the R&D of PDS required in ILC project. This report describes the recent status of the rf source of STF in KEK including the modulator, PDS and LLRF. |
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THP076 | Last SPIRAL 2 10 kW CW RF Coupler Design | 969 |
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The first tests of the SPIRAL 2 coupler have been done successfully in the B-cryomodule of the SPIRAL2 linac. It led to an updated design. We present the new design as well as the results of the last test and conditioning. |
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THP077 | Studies on Input Couplers for Superconducting Cavities | 972 |
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Drastic conditioning time reduction was successfully achieved for the TTF-III couplers at LAL. This was carried out by a systematic study of the different parameters that play a role in the conditioning process. Moreover, many investigations were made in order to have a better understanding of the couplers behaviour. These activities represent some aspects of a larger technology program that is being developed at LAL to study power couplers and multipacting. This paper will give an overview of some of these studies, the future experiments on couplers at LAL and the development of the associated technology program. |
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THP078 | High Power RF Supplies for the FAIR Injector Linacs | 975 |
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During the LINAC conference in Knoxville 2006 the operating frequency of the FAIR proton linac was fixed at 325.224 MHz. Even though the six CH-Structures need slightly different rf levels, the proton linac will be equipped with identical rf power sources. That applies although for the RFQ structure. To supply the FAIR accelerators with a good beam quality by the UNILAC as the high current heavy ion injector for FAIR, as well as an high duty factor accelerator for nuclear physics experiments, different upgrades and modifications have to be made at the rf components. In addition there has to be an upgrade for a planned 50% duty cycle mode, higher beam load within the post-stripper section as well as the provision of an excellent rf operation for the next 30 years. Discussions on possible collaborations with CERN in terms of LLRF and the combining of the procurement for tube amplifiers for bunching cavities are on the way. This paper describes the actual status of the proton linac rf system and the future requirements for the existing UNILAC rf systems. |
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THP079 | Operation Experience with the FLASH RF Waveguide Distribution System at DESY | 978 |
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The rf stations for the FLASH linear accelerator at DESY provide rf power up to more than 5 MW, 1.3 ms and 10 Hz at 1.3 GHz for forty-eight superconducting cavities grouped into six cryogenic modules and for one normal conducting rf gun. A WR650 waveguide distribution system distributes the power generated by five active rf stations using 5 MW single beam and a 10 MW multibeam klystron to the cavities and the gun. Since FLASH is based on the Tesla Test Facility, TTF, a number of different distribution layouts for the different modules and the gun have been developed and used over the years in terms of type of components and distribution scheme. This paper presents the layout and summarizes the experience with the existing waveguide distribution system. |
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THP080 | Elimination of Parasitic Oscillations in RF Tube Amplifier for High Power Application | 981 |
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For the heavy ion therapy center HIT in Heidelberg a 1.6 MW power amplifier for 217 MHz was built to supply the 7 MeV/u IH cavity. The inherent parasitic oscillations of the RF tube increases rapidly the anode current until the system switches off. For the elimination of those parasitic oscillations ferrite material is used. The electro magnetic fields are simulated to find an optimal positioning of the ferrite material in the anode cavity such that only the parasitic oscillations are attenuated without affecting the fundamental mode. |
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THP081 | Development of All Solid State Bouncer Compensated Long Pulse Modulators for LEP 1MW Klystrons to be Used for LINAC4 Project at CERN | 984 |
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Funding: Department of Atomic Energy, India. The work is done under DAE CERN Collaboration under NAT Protocol. |
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THP085 | Cooling System Design of Compact Klystron Modulator Power Supply in the XFEL Project at SPring-8 | 987 |
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A klystron modulator power supply for XFEL project at SPring-8 has been developed, which concepts are a compact body, a low noise, and a good stability. The cooling system of the power supply is one of the most important key for the stable modulator. For example, temperature change of insulation oil in the tank caused drift of the klystron voltage, and higher oil temperature deteriorates insulation oil and electric components. We adopted simple and compact cooling systems utilizing natural conviction cooling, because of low costs, limited space, and maintenance free. In order to estimate the requisite cooling ability, we designed four types of cooling panels and measured the natural conviction heat transfer coefficient between the oil and each cooling panels. Using the results, we designed cooling systems composed of water cooling panels placed on the side walls and a water pipe hanged from the ceiling panel. The temperature of the inner oil of the power supply in the rated operation was suppressed below 43 degree C, which is agreed with our expectation. In this paper we present the design and ability of the power supply, and the key point of oil cooling. |
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THP086 | Cold Cathode Electron Tube Toward Plenty Multi Beam Tube | 990 |
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The multi beam electron tube with a lot of beam pipes is required for the low applied voltage and the high frequency because the efficiency has a limit according to the perveance. However, the total heater power becomes too high if many thermal cathodes are used. Thus the cold cathode such as the carbon nano tube (CNT) is suitable for such a multi beam electron tube. Further the cold cathode has the advantage to work as a switching device since the metal grid close to the cathode can be used. The design and the fundamental test of the partial model will be presented. |
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THP087 | Quarter-Wave-Stub Resonant Coupler | 993 |
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Most small proton and other ion linacs involve two different linac structures, namely an RFQ linac section and some other, more efficient, linac structure, such as the Drift Tube Linac (DTL), the interdigital (Wideroe) linac, or the Rf Focused Interdigital (RFI) linac. Such linacs can benefit a lot by being resonantly coupled into a single resonant unit. The resonantly coupled structures can be driven by a single rf power system, through single rf drive loop, at a single rf frequency. The relative phase and relative amplitude of the fields in the two structures are locked by the resonant coupler. Such systems require no control of phase of the rf power. By designing the rf power system to track the resonant frequency of the combined structures, the control of the resonant frequencies of the two structures is greatly simplified. A simple, compact, resonant coupler, based on a quarter-wave-stub, will be described. Models of this resonant couple have been tuned and adjusted, and are scheduled to be tested at operating powers in the early fall (2008). |
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THP088 | High Power 325 MHz Vector Modulators for the Fermilab High Intensity Neutrino Source (HINS) | 996 |
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One of the goals of the low energy 60 MeV section of the Fermilab HINS H- linac is to demonstrate that a total of 40 rf cavities can be powered by a single 2.5 MW, 325 MHz klystron. This requires individual vector modulators at the input of each rf cavity to independently adjust the amplitude and phase of the rf input signal during the 3.5 ms rf pulse. Two versions of vector modulators have been developed; a 500 kW device for the RFQ and a 75 kW modulator for the remaining rf cavities. High power test results showing the vector modulator phase and amplitude responses will be presented. |
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THP089 | High Power L-Band Fast Phase Shifter | 999 |
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Following development and testing a prototype waveguide-based high power phase shifter, a design concept of a high power fast phase shifter has been developed. The shifter uses ferrite blocks positioned in a rectangular waveguide. The waveguide cross-section is chosen to suppress most of resonances that could otherwise be a limiting factor for the phase shifter high power performance. Base bias field is created with the use of permanent magnets. Low inductance coils in the same magnetic circuit excite fast (pulsed) bias field component. The waveguide is designed in a way to ensure that the pulsed magnetic field penetrates inside the waveguide with minimum delay while allowing effective heat extraction from the ferrite blocks. This report provides details of the system design, including expected rf behavior and frequency range. |
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THP090 | Marx Bank Technology for Accelerators and Colliders | 1002 |
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Funding: U.S. Department of Energy SBIR Program |
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THP093 | Power Coupler and Tuner Development for Superconducting Quarter-Wave Resonators | 1005 |
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The construction of a reaccelerator for secondary ion beams is currently underway at the National Superconducting Cyclotron Laboratory (NSCL). The reaccelerator linac will use superconducting quarter-wave resonators (QWR) operating at 80.5 MHz with beta = 0.041 and beta = 0.085. A coaxial probe-type rf fundamental power coupler (FPC) will be used for both QWR types. The power coupler makes use of a commercially-available feedthrough to minimize the cost. The FPC has been simulated and optimized for operation at 80.5 MHz using a finite element electromagnetics code. Prototype FPC have been fabricated and conditioned with traveling wave and standing wave power using a 1 kW amplifier. A niobium tuning plate is incorporated into the bottom flange of the QWR. The tuner is actuated by a stepping motor for slow (coarse) tuning and a stacked piezoelectric element in series for fast (fine) tuning. A prototype tuner for the beta = 0.041 QWR has been tested on the cavity at room temperature. This paper will cover the design, fabrication, and testing of the prototype coupler and tuner. |
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THP094 | Leveraging the LEDA High Voltage Power Supply Systems for the LANSCE Refurbishment Project | 1008 |
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Funding: Work supported by the NNSA, U. S. Department of Energy under contract DE-AC52-06NA25396. |
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THP095 | Progress Towards the LANSCE RF System Refurbishment | 1011 |
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The Los Alamos Neutron Science Center (LANSCE) is in the conceptual design 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 consist of replacing all the 201 MHz rf amplifiers, replacing greater than 75% of the 805 MHz rf systems with a combination of high efficiency klystrons and new klystrons of the existing style, replacing four high voltage systems, and replacing all the low level rf cavity field control systems along the accelerator. System designs and requirements will be presented and the project plan will be discussed. |
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THP096 | Next Generation IGBT Switch Plate Development for the SNS High Voltage Converter Modulator | 1012 |
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Funding: Work supported by the U.S. Department of Energy under contract DE-AC05-00OR22725 |
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THP097 | ILC Marx Modulator Development Program Status | 1015 |
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Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 |
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THP098 | RF Vector Control for Efficient Fan-Out Power Distribution | 1018 |
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Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. |
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THP099 | Spallation Neutron Source Superconducting Linac Klystron to Cavity Mismatch Effects and Compensation | 1021 |
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Funding: Oak Ridge National Laboratory, P.O. Box 2008 Oak Ridge, Tennessee 37831-6285 managed by UT-BATTELLE, LLC for the U.S. Department of Energy Under Contract DE-AC05-00OR22725 |
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