skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: X-Band Crab Cavities for the CLIC Beam Delivery System

Abstract

The CLIC machine incorporates a 20 mrad crossing angle at the IP to aid the extraction of spent beams. In order to recover the luminosity lost through the crossing angle a crab cavity is proposed to rotate the bunches prior to collision. The crab cavity is chosen to have the same frequency as the main linac (11.9942 GHz) as a compromise between size, phase stability requirements and beam loading. It is proposed to use a HE11 mode travelling wave structure as the CLIC crab cavity in order to minimise beam loading and mode separation. The position of the crab cavity close to the final focus enhances the effect of transverse wake-fields so effective wake-field damping is required. A damped detuned structure is proposed to suppress and de-cohere the wake-field hence reducing their effect. Design considerations for the CLIC crab cavity will be discussed as well as the proposed high power testing of these structures at SLAC. Design of a crab cavity for CLIC is underway at the Cockcroft Institute in collaboration with SLAC. This effort draws on a large degree of synergy with the ILC crab cavity developed at the Cockcroft Institute and other deflecting structure development at SLAC. Amore » study of phase and amplitude variations in the cavity suggests that the tolerances are very tight and require a 'beyond state of the art' LLRF control system. A study of cavity geometry and its effect on the cavity fields has been performed using Microwave studio. This study has suggested that for our cavity an iris radius between 4-5 mm is optimum with an iris thickness of 2-3 mm based on group velocity and peak fields. A study of the cavity wakefields show that the single bunch wakes are unlikely to be a problem but the short bunch spacing may cause the multi-bunch wakefields to be an issue. This will require some of the modes to be damped strongly so that the wake is damped significantly before any following bunch arrives. Various methods of damping have been investigated and suggest that waveguide damping in the cells should provide sufficient damping in the vertical plane, which is the most sensitive.« less

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1029902
Report Number(s):
SLAC-PUB-14769
arXiv:0903.2116; TRN: US1105855
DOE Contract Number:  
AC02-76SF00515
Resource Type:
Conference
Journal Name:
arXiv:0903.2116
Additional Journal Information:
Conference: To appear in the proceedings of 44th ICFA Advanced Beam Dynamics Workshop: X-Band RF Structure and Beam Dynamics, Warrington, United Kingdom, 1-4 Dec 2008
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; AMPLITUDES; BEAM DYNAMICS; CAVITIES; CONTROL SYSTEMS; DAMPING; DESIGN; GEOMETRY; LINEAR ACCELERATORS; LUMINOSITY; PHASE STABILITY; STANFORD LINEAR ACCELERATOR CENTER; TESTING; THICKNESS; TRAVELLING WAVES; VELOCITY; WAVEGUIDES; Accelerators,PHYS

Citation Formats

Burt, G., Ambattu, P.K., Dexter, A.C., Abram, T., /Cockcroft Inst. Accel. Sci. Tech. /Lancaster U., Dolgashev, V., Tantawi, S., /SLAC, Jones, R.M., and /Cockcroft Inst. Accel. Sci. Tech. /Manchester U. X-Band Crab Cavities for the CLIC Beam Delivery System. United States: N. p., 2011. Web.
Burt, G., Ambattu, P.K., Dexter, A.C., Abram, T., /Cockcroft Inst. Accel. Sci. Tech. /Lancaster U., Dolgashev, V., Tantawi, S., /SLAC, Jones, R.M., & /Cockcroft Inst. Accel. Sci. Tech. /Manchester U. X-Band Crab Cavities for the CLIC Beam Delivery System. United States.
Burt, G., Ambattu, P.K., Dexter, A.C., Abram, T., /Cockcroft Inst. Accel. Sci. Tech. /Lancaster U., Dolgashev, V., Tantawi, S., /SLAC, Jones, R.M., and /Cockcroft Inst. Accel. Sci. Tech. /Manchester U. Tue . "X-Band Crab Cavities for the CLIC Beam Delivery System". United States. https://www.osti.gov/servlets/purl/1029902.
@article{osti_1029902,
title = {X-Band Crab Cavities for the CLIC Beam Delivery System},
author = {Burt, G. and Ambattu, P.K. and Dexter, A.C. and Abram, T. and /Cockcroft Inst. Accel. Sci. Tech. /Lancaster U. and Dolgashev, V. and Tantawi, S. and /SLAC and Jones, R.M. and /Cockcroft Inst. Accel. Sci. Tech. /Manchester U.},
abstractNote = {The CLIC machine incorporates a 20 mrad crossing angle at the IP to aid the extraction of spent beams. In order to recover the luminosity lost through the crossing angle a crab cavity is proposed to rotate the bunches prior to collision. The crab cavity is chosen to have the same frequency as the main linac (11.9942 GHz) as a compromise between size, phase stability requirements and beam loading. It is proposed to use a HE11 mode travelling wave structure as the CLIC crab cavity in order to minimise beam loading and mode separation. The position of the crab cavity close to the final focus enhances the effect of transverse wake-fields so effective wake-field damping is required. A damped detuned structure is proposed to suppress and de-cohere the wake-field hence reducing their effect. Design considerations for the CLIC crab cavity will be discussed as well as the proposed high power testing of these structures at SLAC. Design of a crab cavity for CLIC is underway at the Cockcroft Institute in collaboration with SLAC. This effort draws on a large degree of synergy with the ILC crab cavity developed at the Cockcroft Institute and other deflecting structure development at SLAC. A study of phase and amplitude variations in the cavity suggests that the tolerances are very tight and require a 'beyond state of the art' LLRF control system. A study of cavity geometry and its effect on the cavity fields has been performed using Microwave studio. This study has suggested that for our cavity an iris radius between 4-5 mm is optimum with an iris thickness of 2-3 mm based on group velocity and peak fields. A study of the cavity wakefields show that the single bunch wakes are unlikely to be a problem but the short bunch spacing may cause the multi-bunch wakefields to be an issue. This will require some of the modes to be damped strongly so that the wake is damped significantly before any following bunch arrives. Various methods of damping have been investigated and suggest that waveguide damping in the cells should provide sufficient damping in the vertical plane, which is the most sensitive.},
doi = {},
journal = {arXiv:0903.2116},
number = ,
volume = ,
place = {United States},
year = {2011},
month = {11}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share: