LINAC 2006 - List of Keywords (superconducting-RF)

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

superconducting-RF

Paper	Title	Other Keywords	Page
MOP016	SRF Linac Solutions for 4GLS at Daresbury	linac, damping, acceleration, electron	64
	P. A. McIntosh, C. D. Beard, D. M. Dykes CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
	The proposed 4th Generation Light Source (4GLS) facility, anticipated to be located at Daresbury Laboratory in the UK, will extensively utilise Superconducting RF (SRF) Linacs for each stage of its multi-beam acceleration. IR, XUV and VUV FEL devices, and particularly the ability to combine these sources for users, provide a unique capability for this Energy Recovery Linac (ERL) based accelerator. The CW mode of operation for the SRF Linacs necessitates that adequate provision is made for delivering the required RF power and also damping of the beam induced HOMs to manageable levels. This paper outlines the RF requirements and proposed solutions for each of the 4GLS Linacs.

TUP026	Status of the XFEL Testcavity Program	vacuum, electron, gun, superconductivity	302
	D. Reschke, A. Brinkmann, J. Iversen, W. Singer DESY, Hamburg
	In preparation of the European XFEL-project a testcavity program of about 25 1.3GHz niobium single-cell cavities was launched at DESY beginning of 2005 in parallel to the accelerator nine-cell structure activities. After successful start-up of the DESY in-house fabrication main topics of the program are the optimisation of cavity electron beam welding preparation, the performance of large grain niobium and the qualification of further niobium vendors for cavity production. So far reproducibly all cavities (TESLA cell shape) exceed gradients of 30 MV/m at high Q-values. An electropolished mono-cell fabricated of large grain material reached 41 MV/m at Qo = 1.4·10¹⁰. The present status and results of the program are presented.

TUP036	Large Grain Superconducting RF Cavities at DESY	superconductivity, scattering, free-electron-laser, RF-structure	327
	W. Singer, A. Brinkmann, J. Iversen, G. Kreps, A. Matheisen, D. Reschke, X. Singer DESY, Hamburg
	The DESY R&D program on cavities fabricated from large grain niobium explores the potential of this material for the production of approx. 1000 nine-cell cavities for the European XFEL. The program investigates both, the basic material properties comparing large grain material to standard sheet niobium and the material availability, fabrication and preparation aspects. Several single-cell cavities of TESLA shape have been fabricated from large grain niobium. A gradient up to 41 MV/m at Q₀ = 1.4·10¹⁰ (TB = 2K) was measured after electropolishing. Recently the first large grain nine-cell cavities worldwide have been produced under contract of DESY with ACCEL Instruments Co. The first cavity is already tested with an accelerating gradient of 29 MV/m after BCP (Buffered Chemical Polishing) treatment.

TH1002	Cryomodule Test Facilities and Multicell Cavity Performance for the ILC	linac, linear-collider, klystron, controls	516
	H. Hayano KEK, Ibaraki
	To address the ILC Main Linac gradient, which are greater than 35MV/m at vertical test and greater than 31.5MV/m in the operation of the cryomodule, ILC-GDE organized several task forces in the R&D board. They are S0 task force, S1 task force, and S2 task force. The charge of S0 is to achieve 35MV/m in the qualification with reasonable yield. S1 is to achieve 31.5MV/m operation of cryomodule. And S2 is to estimate how large test facility is required to test chain of cryomodules and to make industrialization of cryomodule production. The paper reports the task force activities status together with existing R&D of multicell cavity performance and cryomodule test facility status.

THP010	Low-level RF system for STF	controls, klystron, feedback, linac	586
	T. Matsumoto, S. Fukuda, H. Katagiri, S. Michizono, Y. Yano KEK, Ibaraki Z. Geng IHEP Beijing, Beijing
	The Super-conducting RF Test Facility (STF) has been constructed to establish the production technique of a cavity having a high gradient and operated for the high power testing of the klystron and couplers being installed in the superconducting cavities. An accelerating electric field stability of 0.3% (rms) in amplitude and 0.3 degree (rms) in phase is also required for the RF system in STF. In order to satisfy these requirements, a digital LLRF control system using FPGA is adopted, and the components required for the digital LLRF system have been developed.

THP012	Adaptive Tuner Control in TRIUMF ISAC 2 Superconducting LINAC using Kalman Filter	controls, feedback, linac, pick-up	592
	K. Fong, M. P. Laverty, Q. Zheng TRIUMF, Vancouver
	The TRIUMF ISAC 2 RF control system uses phase locking self-excited control. Amplitude, phase and frequency control is achieved with I/Q voltage injection, and forward RF power is minimized with a tuner feedback loop. The phase difference between the input coupler and the output pickup drives a velocity servo system to provide tuning control. However, the presence of microphonics in the cryomodule, although under control by the Quadrature loop, still presents a noisy interference on the phase difference for the tuner. The tuner will follow this noise and generate more microphonics as a result. A first-order Kalman filter is used for an estimation of the phase difference and reduces the movement of the tuner.

THP022	Status of RF Sources in Super-Conducting RF Test Facility (STF) at KEK	klystron, controls, acceleration, linac	613
	S. Fukuda, M. Akemoto, H. Hayano, H. Katagiri, S. Kazakov, S. Matsumoto, T. Matsumoto, S. Michizono, H. Nakajima, K. Nakao, T. Shidara, T. Takenaka, Y. Yano, M. Yoshida KEK, Ibaraki
	Super-conducting rf test facility (STF) has been progessing in KEK since 2005. In this paper, we describe the current status of rf sources in STF. STF rf sources comprise of a long pulse modulator with bouncer circuit, a pulse transformer, an L-band 5MW klystron, power distribution system and low level rf system. We have completed the construction of the first rf system and have been testing for the system evaluation and for the coupler test of the super-conducting cavity. We have a schedule to feed a power to the cryomodule with 8 super-conducting cavities in December of 2006. We also describe the plan of the second rf sources of STF.

THP051	Status of 3.9-GHz Superconducting RF Cavity Technology at Fermilab	vacuum, controls, linac, higher-order-mode	695
	H. Edwards, T. T. Arkan, H. Carter, C. A. Cooper, M. Foley, E. R. Harms, T. K. Khabiboulline, D. V. Mitchell, D. O. Olis, A. M. Rowe, N. Solyak, S. Tariq Fermilab, Batavia, Illinois
	Fermilab is involved in an effort to design, build, test and deliver 3.9 GHz superconducting RF cavities with a goal to deliver one 'third harmonic' cryomodule containing four cavities in early 2007 for use at the DESY TTF III Project. The design gradient of these cavities is 19 MV/m. This effort involves design, fabrication, intermediate testing, assembly, and eventual delivery of the four cavity cryomodule. We report on all facets of this enterprise from design through future plans. Included will be early test results of single 9-cell cavities, lessons learned, and other findings.

THP066	Lorentz-Force Detuning Analysis for Low-Loss, Re-entrant and Half-Reentrant Superconducting RF Cavities	simulation, coupling, linear-collider, collider	734
	E. Zaplatin FZJ, Jülich T. L. Grimm, W. Hartung, M. J. Johnson, M. S. Meidlinger, J. Popielarski, R. C. York NSCL, East Lansing, Michigan
	The RF design of a superconducting elliptical cavity requires a trade-off in the optimization of the cell shape between the region of high electric field and the region of high magnetic field. In practice, the cavity performance may be limited not by the RF characteristics, but by detuning due to the Lorentz force, bath pressure fluctuations, or microphonics; Lorentz force detuning is of concern primarily for pulsed accelerators such as the proposed International Linear Collider. Hence the structural properties must also be taken into account in the cavity design. Several new cavity shapes are being developed in which the surface magnetic field is decreased relative to the TeSLA cavity shape, with the goal of reaching a higher accelerating gradient. This study will compare the Lorentz force detuning characteristics of the TeSLA, "low-loss", "reentrant", and "half-reentrant" cavity middle cells, and explore possible methods for stiffening the structures.