07 Accelerator Technology

T08 RF Power Sources

Paper	Title	Page
TUPCH150	Improved 1.3 GHz Inductive Output Tube for Particle Accelerators	1373
	A.E. Wheelhouse e2v technologies, Chelmsford, Essex
	There is an increasing requirement for RF power sources in the L-band frequency range for operation in particle accelerators. Previously (at PAC 2005), the design, development and initial testing of a new L-band 16kW cw inductive output tube (IOT) was described. This paper discusses the detailed performance characteristics of the latest EEV IOT116LS embodying the most recent design improvements and presents data demonstrating its suitability for operation at 1.3GHz in the next generation of light sources.
TUPCH151	ERLP/4GLS Low Level Radio Frequency System	1376
	A.J. Moss, P.A. Corlett, J.F. Orrett, J.H.P. Rogers CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
	The Energy Recovery Linac Prototype (ERLP) being constructed at Daresbury Laboratory will use an analog-based low level RF (LLRF) control system designed and built at FZR Rossendorf. Once the machine is operational, the testing and development of a digital LLRF feedback system will take place using the ERLP as a testbed.
TUPCH152	MICE RF Test Stand	1379
	P.A. Corlett, A.J. Moss, J.F. Orrett CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
	The Muon Ionization Cooling Experiment (MICE) RF test stand is being assembled at Daresbury Laboratory. This will provide a test bed for power amplifiers to produce the 2MW 200MHz RF for the MICE experiment RF cavities. Initial design and proposed layout of the RF system are described.
TUPCH153	IOT Testing at the ERLP	1382
	J.F. Orrett, S.R. Buckley, P.A. Corlett, A.J. Moss CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire S. Rains Diamond, Oxfordshire
	The testing of Inductive Output Tubes (IOT) at 1.3GHz is underway for use on the Energy Recovery Linac Prototype (ERLP) being constructed at Daresbury Laboratory. A 50KV high voltage power supply (HVPS) has been commissioned and characterised for use as a test RF supply. This will be used to power the ERLP RF system in both continuous and pulse modes of operation. First results are presented of the IOTs and the use of the HVPS system.
TUPCH154	RF Amplifier for Next Generation Light Sources	1385
	J.S. Przybyla, E. Radcliffe e2v Technologies, Essex
	This paper describes the design concepts and development issues around generating a compact 16kW 1.3GHz RF amplifier for use in the next generation of light sources. These amplifiers need to be operated for extended periods to maximise use of the facility and so high reliability and availability are of key importance. Equally important are the capabilities to have extensive self-monitoring and fault prediction, autonomous operation, low heat dissipation to air, and easy maintenance. The design and development of such an RF amplifier based on the latest e2v technologies 1.3GHz inductive output tube (IOT) will be described. The RF amplifier equipment makes extensive use of commercially available products and industry collaborations to produce an amplifier that meets all the requirements yet can be manufactured and operated in a most cost effective manner. Prototype equipment will be shown at EPAC 06.
TUPCH155	2D and 1D Surface Photonic Band Gap Structures for Accelerator Applications	1388
	I.V. Konoplev, A.W. Cross, W. He, P. MacInnes, A. Phelps, C.W. Robertson, K. Ronald, C.G. Whyte USTRAT/SUPA, Glasgow
	High frequency (26.5GHz to 40GHz), high power (tens of MW) microwave sources are required for cavity testing and conditioning applications in accelerators such as CLIC. The first study of microwave radiation from a co-axial Free-Electron Maser (FEM) based on a two-mirror cavity formed by a 2D Surface Photonic Band Gap (SPBG) structure (input mirror 10.4cm) and 1D SPBG structure (output mirror 10cm) is presented. The electron beam source consisted of a magnetically insulated plasma flare emission carbon cathode. Application of a 450kV voltage pulse of duration ~250ns across the cathode and grounded anode resulted in the production of a 7.0cm diameter annular electron beam of current ~1500A. The output radiation power from the FEM was measured using a Ka-band horn with 60dB of attenuation in front of a microwave detector located at a distance of 1.5m from the output window. By integrating the microwave power measured at the detector over the radiation pattern a total power of 50 (±10) MW corresponding to an efficiency of ~9% was calculated. The location of the operating frequency was found to lie between 35GHz and 39GHz, which agrees with theoretically predicted frequency of 37.2GHz.
TUPCH156	Design and Simulation of a Cusp Gun for Gyro-amplifier Application in High Frequency RF Accelerators	1391
	D.H. Rowlands, A.W. Cross, W. He, A. Phelps, E.G. Rafferty, C.W. Robertson, K. Ronald, J. Thomson, C.G. Whyte, A.R. Young USTRAT/SUPA, Glasgow
	Gyro-amplifiers have potential as the high frequency RF drivers for particle accelerators. They require relativistic electron beams with low velocity spread and with a high fraction of the electron energy associated with the cyclotron motion. For harmonic operation and mode control an axis-encircling beam is desirable. The passage of an electron beam through a non-adiabatic magnetic field reversal (cusp) converts part of the electron beam's axial velocity into axis-encircling transverse velocity. A cusp-based electron beam forming system, yielding a 10MW, 150kV, 70A axis-encircling beam will be presented. This cusp gun is being designed as the electron beam source for a microwave gyro-amplifier that is relevant for high frequency accelerator applications. The latest results from numerical simulations and experiments will be presented and compared.
TUPCH158	High Power, Solid State RF Amplifiers Development for the EURISOL Proton Driver	1394
	F. Scarpa, A. Facco, D. Zenere INFN/LNL, Legnaro, Padova
	A 5 kW solid-state RF amplifier for the SPES and EURISOL projects has been built and extensively tested. High reliability and low cost are the main goals for this device, an evolution of a 2.5 kW unit previously developed and presented at EPAC 02. The description of the amplifier, especially designed for superconducting cavities, its characteristics and test results will be illustrated and discussed, as well as the design and construction of two new 10 kW amplifier units that have recently started.
TUPCH159	High Power Waveguide Switching System for SPring-8 Linac	1397
	T. Taniuchi, T. Asaka, H. Dewa, H. Hanaki, T. Kobayashi, A. Mizuno, S. Suzuki, H. Tomizawa, K. Yanagida JASRI/SPring-8, Hyogo-ken A. Miura Nihon Koshuha Co., Ltd., Yokohama
	A vacuum waveguide switch has been developed to build a backup system of an RF source for the electron injector system and the klystron drive line in the SPring-8 linac. A high power test of the waveguide switch was carried out, and the maximum RF power of 62 MW in peak, 1μsecond in pulse width and 10 pps in repetition rate was achieved without serious problems in RF and vacuum characteristics. The backup system utilizing this waveguide switch has been installed in the electron injector system.
TUPCH160	Novel Conception of Beam Temperature in Accelerator and Applications	1400
	D. Dong IHEP Beijing, Beijing
	In this paper, we will introduce a novel conception of beam temperature in accelerator, discuss the calculation method. And finally the author will show an example on the beam temperature in a klystron.
TUPCH162	Operation Results of 1 MW RF Systems for the PEFP 20 MeV Linac	1402
	K.T. Seol, Y.-S. Cho, H. S. Kim, H.-J. Kwon KAERI, Daejon K.R. Kim PAL, Pohang, Kyungbuk
	The PEFP 20 MeV linear accelerator is composed of a 3 MeV RFQ and 20 MeV DTL. Two sets of 1MW, 350MHz RF systems drive the RFQ and DTL. The RF system can perform a 100% duty operation. The TH2089F klystron is used as an RF source. During the test operation, only the driving RF signal of the klystron was operated in pulse mode, while the electron beam was maintained in DC mode. The klystron power supplies and cooling systems were also operated in 100% duty mode. In this paper, the operation results of 1 MW RF systems including klystron power supply and cooling system are discussed and propose possible options to improve the operation conditions based on the results.
TUPCH163	Status of 30 GHz High Power RF Pulse Compressor for CTF3	1405
	I. Syratchev CERN, Geneva
	A 70 ns 30 GHz pulse compressor with resonant delay lines has been built and installed in the CTF3 test area to obtain the high peak power of 150 MW necessary to demonstrate the full performance of the new CLIC accelerating structure. This pulse compressor will be commissioned at high power in 2006. Different methods to provide fast RF phase switching are discussed. The current status of the CTF3 RF pulse compressor commissioning and first results are presented.
TUPCH164	Ka-band Test Facility for High-gradient Accelerator R&D	1408
	M.A. LaPointe, J.L. Hirshfield, E.V. Kozyrev Yale University, Physics Department, New Haven, CT A.A. Bogdashov, A.V. Chirkov, G.G. Denisov, A.S. Fix, D.A. Lukovnikov, V.I. Malygin, Yu.V. Rodin, M.Y. Shmelyov IAP/RAS, Nizhny Novgorod S.V. Kuzikov, A.G. Litvak, O.A. Nezhevenko, M.I. Petelin, A.A. Vikharev, V.P. Yakovlev Omega-P, Inc., New Haven, Connecticut G.V. Serdobintsev BINP SB RAS, Novosibirsk S.V. Shchelkunov Columbia University, New York
	Achievement of high acceleration gradients in room-temperature structures requires basic studies of electric and magnetic RF field limits at surfaces of conductors and dielectrics. Facilities for such studies at 11.4 GHz have been in use at KEK and SLAC; facilities for studies at 17.1 GHz are being developed at MIT and UMd; and studies at 30 GHz are being conducted at CERN using the CLIC drive beam to generate short intense RF pulses. Longer pulse studies at 34 GHz are to be carried out at a new test facility being established at the Yale Beam Physics Laboratory, built around the Yale/Omega-P 34-GHz magnicon. This high-power amplifier, together with an available ensemble of components, should enable tests to be carried at up to about 9 MW in 1 mcs wide pulses at up to four output stations or, using a power combiner, at up to about 35 MW in 1 mcs wide pulses at a single station. RF pulse compression is planned to be used to produce 100-200 MW, 100 ns pulses; or GW-level, 1 mcs wide pulses in a resonant ring. A number of experiments have been prepared to utilize multi-MW 34-GHz power for accelerator R&D, and users for future experiments are encouraged to express their interest.
TUPCH165	Compact Single-channel Ka-band SLED-II Pulse Compressor	1411
	S.V. Kuzikov, S.V. Kuzikov, M.E. Plotkin, A.A. Vikharev Omega-P, Inc., New Haven, Connecticut J.L. Hirshfield Yale University, Physics Department, New Haven, CT
	Basic studies of factors that limit RF fields in warm accelerator structures require experiments at RF power levels that can only be produced from an intense drive beam, as with CLIC studies, or using pulse compression of output pulses from the RF source. This latter approach is being implemented to compress output pulses from the Yale/Omega-P 34-GHz magnicon to produce ~100-200 MW, 100 ns pulses. A new approach for passive pulse compression is described that uses a SLED-II-type circuit operating with axisymmetrical modes of the TE0n type that requires only a single channel instead of the usual double channel scheme. This allows avoidance of a 3-dB coupler and need for simultaneous fine tuning of two channels. Calculations show that with this device at 34 GHz one can anticipate a power gain of 3.3:1, and an efficiency of 66% for a 100 ns wide output pulse, taking into account losses and a realistic 50-ns long 180 degrees phase flip.
TUPCH166	Multi-megawatt Harmonic Multiplier for Testing High-gradient Accelerator Structures	1414
	V.P. Yakovlev Omega-P, Inc., New Haven, Connecticut J.L. Hirshfield Yale University, Physics Department, New Haven, CT
	Basic studies for determining the RF electric and magnetic field limits on surfaces of materials suitable for accelerator structures for a future multi-TeV collider, and for the testing of the accelerator structures and components themselves, require stand-alone high-power RF sources at several frequencies, from 10 to 45 GHz. A relatively simple and inexpensive two-cavity harmonic multiplier at 22.8, 34.3, or 45.7 GHz is suggested to be the stand-alone multi-MW RF power source for this application. The design is based on the use of an existing SLAC electron gun, such as the XP3 gun, plus a beam collector as used on the XP3 klystron. RF drive power would be supplied from an 11.4 GHz, 50 or 75 MW SLAC klystron and modulator, and a second modulator would be used to power the gun in the multiplier. Preliminary computations show that 64, 55, and 47 MW, respectively, can be realized in 2nd, 3rd, and 4th harmonic multipliers at 22.8, 34.3, and 45.7 GHz using 75 MW of X-band drive power.
TUPCH167	Modeling and Simulation Results of High-power HOM IOTs	0
	E.L. Wright, H.P. Bohlen CPI, Palo Alto, California
	The inductive output tube (IOT) continues to be the device-of-choice for terrestrial UHF broadcast applications due to its high efficiency, linearity, compactness, etc.; the same reasons that make this an attractive choice for scientific users. The IOT is being considered for a growing number of accelerator programs requiring multi-kilowatts of continuous wave power, at UHF and L-band frequencies. A number of vacuum electron device manufacturers are developing IOTs in support of these programs. There are an equal number of accelerator programs that operate pulsed, requiring high peak powers, where the only sources available are klystrons and MBKs. For these applications a higher-order mode IOT (HOM IOT) shows great promise for the same reasons described above. Modeling and simulation results for devices built to operate within the UHF and L-band frequency ranges will be shown, at power levels up to 5 MW.
TUPCH168	IOTs: The Next Generation RF Power Sources for Accelerators	0
	Y. Li, H.P. Bohlen, R.N. Tornoe, E.L. Wright CPI, Palo Alto, California
	A new generation of Inductive Output Tubes (IOT) have been developed with a focus on cost reduction, robustness, stability, enhanced power, improved gain and efficiency. As demonstrated with our L-band integral cavity IOT, a new family of IOTs can operate as CW or pulse amplifiers with up to 80 kW CW and 120 kW peak output power. Switching between the CW and pulse mode is easy and simple. In this paper, we will present our new compact designs and the latest performance data.
WEXPA02	New Developments on RF Power Sources	1842
	J. Jacob ESRF, Grenoble
	The classical generation of RF power with klystrons and tetrodes is evolving and changing to meet the demands of higher efficiency and simpler maintenance. Developments of IOT tubes for FEL, Energy Recovery Linacs and Storage Rings, together with solid state technology approaches and combination techniques for high power generation are opening new alternatives to the classical ones. An overview of the new concepts, designs and solutions applied to the new accelerators will be presented. Advantages and drawbacks of new versus classical technologies as well as strategies for the selection will be discussed.
	Transparencies