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Title: High-gradient generation in dielectric-loaded wakefield structures.

Abstract

Dielectric loaded wakefield structures have potential to be used as high gradient accelerator components. Using the high current drive beam at the Argonne Wakefield Accelerator Facility, we employed cylindrical dielectric loaded wakefield structures to generate accelerating fields of up to 86 MV/m, at 10 GHz. Short electron bunches of up to 86 nC are used to drive these fields, either as single bunches or as bunch trains. The structures consist of cylindrical ceramic tubes (cordierite) with a dielectric constant of 4.76, inserted into cylindrical copper waveguides. These standing-wave structures have a field probe near the outer diameter of the dielectric, in order to sample the RF fields generated by the electron bunches. Monitoring the field probe signal serves to verify the absence of electric breakdown in the structures. MAFIA simulations are used to calculate the amplitude of the fields generated by the traversing electrons bunches.

Authors:
; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
971938
Report Number(s):
ANL-HEP-CP-06-68
TRN: US1001426
DOE Contract Number:
DE-AC02-06CH11357
Resource Type:
Conference
Resource Relation:
Conference: 2006 Linear Accelerator Conference (LINAC 06); Aug. 21, 2006 - Aug. 25, 2006; Knoxville, TN
Country of Publication:
United States
Language:
ENGLISH
Subject:
43 PARTICLE ACCELERATORS; 36 MATERIALS SCIENCE; ACCELERATORS; AMPLITUDES; BREAKDOWN; CERAMICS; COPPER; DIELECTRIC MATERIALS; ELECTRONS; LINEAR ACCELERATORS; MONITORING; PERMITTIVITY; PROBES; WAKEFIELD ACCELERATORS; WAVEGUIDES

Citation Formats

Conde, M. E., Antipov, S., Franchini, F., Gai, W., Gao, F., Jing, C., Konecny, R., Liu, W., Power, J. G., Wang, H., Yusof, Z., High Energy Physics, and Euclid Concepts LLC. High-gradient generation in dielectric-loaded wakefield structures.. United States: N. p., 2006. Web.
Conde, M. E., Antipov, S., Franchini, F., Gai, W., Gao, F., Jing, C., Konecny, R., Liu, W., Power, J. G., Wang, H., Yusof, Z., High Energy Physics, & Euclid Concepts LLC. High-gradient generation in dielectric-loaded wakefield structures.. United States.
Conde, M. E., Antipov, S., Franchini, F., Gai, W., Gao, F., Jing, C., Konecny, R., Liu, W., Power, J. G., Wang, H., Yusof, Z., High Energy Physics, and Euclid Concepts LLC. Sun . "High-gradient generation in dielectric-loaded wakefield structures.". United States. doi:.
@article{osti_971938,
title = {High-gradient generation in dielectric-loaded wakefield structures.},
author = {Conde, M. E. and Antipov, S. and Franchini, F. and Gai, W. and Gao, F. and Jing, C. and Konecny, R. and Liu, W. and Power, J. G. and Wang, H. and Yusof, Z. and High Energy Physics and Euclid Concepts LLC},
abstractNote = {Dielectric loaded wakefield structures have potential to be used as high gradient accelerator components. Using the high current drive beam at the Argonne Wakefield Accelerator Facility, we employed cylindrical dielectric loaded wakefield structures to generate accelerating fields of up to 86 MV/m, at 10 GHz. Short electron bunches of up to 86 nC are used to drive these fields, either as single bunches or as bunch trains. The structures consist of cylindrical ceramic tubes (cordierite) with a dielectric constant of 4.76, inserted into cylindrical copper waveguides. These standing-wave structures have a field probe near the outer diameter of the dielectric, in order to sample the RF fields generated by the electron bunches. Monitoring the field probe signal serves to verify the absence of electric breakdown in the structures. MAFIA simulations are used to calculate the amplitude of the fields generated by the traversing electrons bunches.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}

Conference:
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  • Dielectric loaded wakefield structures have potential to be used as high gradient accelerator components. Using the high current drive beam at the Argonne Wakefield Accelerator Facility, we employed cylindrical dielectric loaded wakefield structures to generate accelerating fields of up to 100 MV/m. Short electron bunches (13 ps FWHM) of up to 86 nC are used to drive these fields, either as single bunches or as bunch trains. These tested standing-wave structures have a field probe near the outer edge of the dielectric to sample the RF fields generated by the electron bunches. Monitoring of these high intensity RF fields servesmore » to verify the absence of electric breakdown. Similar cylindrical dielectric loaded structures are used as power extractors, that is, traveling wave structures from which the RF power generated by the drive beam is efficiently coupled out.« less
  • A 15 GHz dielectric loaded wakefield structure has been used to extract energy from a 13 MeV electron beam. Short electron bunches (13 ps FWHM) of up to 43 nC traversed the structure, generating an accelerating field of {approx}23 MV/m. The structure consists of a cylindrical ceramic tube (cordierite) with a dielectric constant of 5, inner and outer radii of 5 mm and 7.49 mm, respectively. The 102 mm long dielectric cylinder is inserted into a cylindrical copper waveguide. Short metallic cylinders, with the same inner and outer radii as the ceramic, are inserted on both ends of the coppermore » waveguide, making it a standing wave structure. A field probe present near the outer edge of the dielectric samples the RF field generated by the electron bunches. This signal is then sent to a mixer circuit, where the 15 GHz signal is down converted to 5 GHz and sent to an oscilloscope. We present measurements made with single electron bunches and also with two bunches separated by 1.5 ns. As a next step in these experiments, another structure, with an output coupler, has been designed and is presently being fabricated.« less
  • Dielectric loaded wakefield structures have potential to be used as high gradient accelerator components. Using the high current drive beam at the Argonne Wakefield Accelerator Facility, we employed cylindrical dielectric loaded wakefield structures to generate accelerating fields of up to 86 MV/m, at 10 GHz. Short electron bunches of up to 86 nC are used to drive these fields, either as single bunches or as bunch trains. The structures consist of cylindrical ceramic tubes (cordierite) with a dielectric constant of 4.76, inserted into cylindrical copper waveguides. These standing-wave structures have a field probe near the outer diameter of the dielectric,more » in order to sample the RF fields generated by the electron bunches. Monitoring the field probe signal serves to verify the absence of electric breakdown in the structures. MAFIA simulations are used to calculate the amplitude of the fields generated by the traversing electrons bunches.« less
  • The Argonne Wakefield Accelerator (AWA) is a facility designed to investigate high gradient wakefield acceleration techniques. Wakefields are excited using a drive beam produced by a 14 MeV high current photoinjector-based linac. A second photocathode gun generates a 4 MeV witness beam which is used as a probe of the wakefields in the device under test. The delay of the witness bunch with respect to the drive bunch can be continuously varied from -100 ps to >1 ns. The drive and witness bunches propagate along collinear or parallel trajectories through the test section. A dipole spectrometer is then used tomore » measure the energy change of the witness beam. The complete wakefield measurement system has been commissioned and wakefield experiments using dielectric structures are underway. Initial experiments have focused on collinear wakefield device geometries where the drive and witness bunches traverse the same structure. For attaining very high gradients we will construct and study step-up transformer structures in which the rf pulse generated by the drive beam is compressed transversely and longitudinally.« less