| Paper |
Title |
Page |
| MOPP093 |
Fast L-band Waveguide Phase Shifter
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769 |
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- S. Kazakov, S. V. Shchelkunov
Omega-P, Inc., New Haven, Connecticut
- J. L. Hirshfield
Yale University, Physics Department, New Haven, CT
- A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio
- E. Nenasheva
Ceramics Ltd., St. Petersburg
- V. P. Yakovlev
Fermilab, Batavia, Illinois
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During the operation of accelerators it is often important to rapidly change the parameters of the RF system, such as cavity resonant frequency, coupling, or electrical length. For this purpose a fast L-band planar phase shifter has been designed, that has advantages compared to the coaxial scheme considered before by the authors (EPAC 06). The phase shifter is based on a new ferroelectric ceramic, whose permittivity changes with application of an external voltage. The switching time depends on only the external HV circuit and can by less than a few microseconds. The conceptual design and electrical parameters of the new phase shifter are presented, as are first results of low power measurements on a 1/3 model.
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| MOPP132 |
Progress Towards Development of an L-Band SC Traveling Wave Accelerating Structure with Feedback
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871 |
| |
- A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio
- P. V. Avrakhov
LPI, Moscow
- S. Kazakov
KEK, Ibaraki
- N. Solyak, V. P. Yakovlev
Fermilab, Batavia, Illinois
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We describe an ongoing experimental program and progress towards development of a conceptual design for a superconducting traveling wave accelerating structure for the ILC. The accelerating gradient can be significantly improved by the use of an RF feedback system redirecting the accelerating wave that passed through the superconducting traveling wave accelerator (STWA) section back to the input of the accelerating structure. The conceptual design of the SC traveling wave accelerator has been considered by P. Avrakhov et al. [PAC07, pp.2538], where shape optimization, coupler cell design and tuning issues in the feedback loop were presented. The proposed TW structure design gives an overall 24% increase in gradient over the 1 m long standing wave structure and potentially can reach 46% if a longer structure is employed. Experimental investigation of the TW SC structure considers tests of a single cavity having the same shape as the regular cell of the full-sized STWA structure, and the same ratio of the RF fields. The details of the individual parts, joint configurations along with some developments on forming and welding of the proposed cavity shapes are discussed.
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| TUPP045 |
Studies of Beam Breakup in Dielectric Structures
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1643 |
| |
- A. Kanareykin, C.-J. Jing, A. L. Kustov, P. Schoessow
Euclid TechLabs, LLC, Solon, Ohio
- W. Gai, J. G. Power
ANL, Argonne, Illinois
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Beam breakup (BBU) effects resulting from parasitic wakefields provide a potentially serious limitation to the performance of dielectric structure based wakefield accelerators. We report on experimental and numerical investigation of BBU and its mitigation. The experimental program focuses on BBU measurements in a number of high gradient and high transformer ratio wakefield devices. New pickup-based beam diagnostics will provide methods for studying parasitic wakefields that are currently unavailable at the AWA facility. The numerical part of this research is based on a particle-Green’s function beam breakup code we are developing that allows rapid, efficient simulation of beam breakup effects in advanced linear accelerators. The goal of this work is to be able to compare the results of detailed experimental measurements with the accurate numerical results and to design an external FODO channel for the control of the beam in the presence of strong transverse wakefields.
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| TUPP046 |
Tunable Ferroelectric Based Technologies for Accelerator Components
|
1646 |
| |
- A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio
- S. Kazakov
KEK, Ibaraki
- E. Nenasheva
Ceramics Ltd., St. Petersburg
- A. Tagantsev
EPFL, Lausanne
- V. P. Yakovlev
Fermilab, Batavia, Illinois
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Low loss ferroelectric materials can be used as key elements in RF tuning and phase shifting components to provide fast, electronic control. These devices are under development for different accelerator applications in X, Ka and L - frequency bands. The exact design of these devices depends on the electrical parameters of the particular ferroelectric material to be used- its dielectric constant, loss tangent and tunability. BST based ferroelectric-oxide compounds have been found to be suitable materials for a fast electrically-controlled tuner for BNL and for high-power fast RF phase shifters to be used for SNS vector modulation applications. We present recent results on the development of BST based ferroelectric compositions synthesized for use in high power technology components. The BST(M) ferroelectrics have been tested using a transverse dc bias field. The tunability factor vs. dc field magnitude has been evaluated and the feasibility of transverse bias tuning for ferroelectric based accelerator components has been demonstrated.
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| WEPP140 |
X-band PASER Experiment
|
2824 |
| |
- A. Kanareykin, P. Schoessow
Euclid TechLabs, LLC, Solon, Ohio
- S. P. Antipov
ANL, Argonne, Illinois
- L. Schächter
Technion, Haifa
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The PASER concept for particle acceleration entails the direct transfer of energy from an active medium to a charged particle beam. The PASER was originally formulated for optical (laser) media; we are pursuing a PASER demonstration experiment based on an optically pumped paramagnetic medium active in the X-band. We report on the development of a relatively high energy density microwave active medium consisting of a fullerene (C60) derivative in a toluene solution. We discuss both the bench test of an amplifier and a beam acceleration experiment under construction that employ this medium as a power source. Applications of the technology to accelerators and microwave components will be presented.
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| THPC105 |
Self-consistent Transverse Dynamics and Interbunch Energy Exchange in Dielectric Loaded Wakefield Accelerating Structures
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3224 |
| |
- I. L. Sheynman
LETI, Saint-Petersburg
- A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio
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The self-consistent transverse dynamics of high current relativistic electron beams used for generating wakefields in dielectric loaded structures is investigated. The primary application of this work is to multi-bunch wakefield acceleration. The maximum distance the high current beam can travel through the structure in the absence of focusing without experiencing beam breakup and the energy transferred to the accelerated electron bunch will be presented. We consider both ramped and uniform charge distributions in the sequence of high current drive bunches. The ramped drive charge distribution is compared to the case of a uniform charge distribution in terms of the requirements for the beam focusing system and the effectiveness of the energy transfer to the accelerated electron bunch.
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