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Title: An Update on Windows, Couplers, Higher-Order-Mode Damping, and Interlocks

Abstract

One of the more consistently challenging problems associated with superconducting RF systems is the introduction of RF power to the cavity and the extraction of beam-induced high-order-mode power from the cavity. This usually involves the transmission of RF power between atmosphere and cavity vacuum spanning a substantial difference in temperature. Dielectric RF windows, usually ceramic, provide atmospheric barriers, and carefully designed thermal transitions of waveguide or coaxial line span the temperature difference while minimizing heat flow to the refrigeration system from conduction and RF losses. There are exceptions, such as a proposed dual-beam accelerator in which RF power is generated in a parallel cavity structure which is RF coupled to accelerating cavities in a common vacuum environment. Some machines such as the DARMSTADT linac do not generate enough higher order mode fields to disturb the beam and require no damping at all. The CEBAF cavity, originally designed for higher current storage ring application at Cornell, generates only a few tenths of a watt with the CEBAF beam which is small enough to be economically dissipated at the cavity temperature and within the cavity vacuum envelope avoiding the need for a window. In general, this is not the case and largermore » values of higher order mode power must be dissipated at some intermediate shield temperature or outside of the cryostat at 300 K. An example is the HOM extraction system developed at KEK which is shown.« less

Authors:
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Sponsoring Org.:
USDOE Office of Energy Research (ER) (US)
OSTI Identifier:
791729
Report Number(s):
CEBAF-PR-93-053; DOE/ER/40150-2004
TRN: US200204%%176
DOE Contract Number:  
AC05-84ER40150
Resource Type:
Conference
Resource Relation:
Conference: 6th RF Superconductivity Workshop, Newport News, VA (US), 10/1993; Other Information: PBD: 1 Oct 1993
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; 36 MATERIALS SCIENCE; DAMPING; DIELECTRIC MATERIALS; HEAT FLUX; INTERLOCKS; LINEAR ACCELERATORS; RF SYSTEMS; STORAGE RINGS; SUPERCONDUCTIVITY; WINDOWS

Citation Formats

Phillips, Larry. An Update on Windows, Couplers, Higher-Order-Mode Damping, and Interlocks. United States: N. p., 1993. Web.
Phillips, Larry. An Update on Windows, Couplers, Higher-Order-Mode Damping, and Interlocks. United States.
Phillips, Larry. 1993. "An Update on Windows, Couplers, Higher-Order-Mode Damping, and Interlocks". United States. https://www.osti.gov/servlets/purl/791729.
@article{osti_791729,
title = {An Update on Windows, Couplers, Higher-Order-Mode Damping, and Interlocks},
author = {Phillips, Larry},
abstractNote = {One of the more consistently challenging problems associated with superconducting RF systems is the introduction of RF power to the cavity and the extraction of beam-induced high-order-mode power from the cavity. This usually involves the transmission of RF power between atmosphere and cavity vacuum spanning a substantial difference in temperature. Dielectric RF windows, usually ceramic, provide atmospheric barriers, and carefully designed thermal transitions of waveguide or coaxial line span the temperature difference while minimizing heat flow to the refrigeration system from conduction and RF losses. There are exceptions, such as a proposed dual-beam accelerator in which RF power is generated in a parallel cavity structure which is RF coupled to accelerating cavities in a common vacuum environment. Some machines such as the DARMSTADT linac do not generate enough higher order mode fields to disturb the beam and require no damping at all. The CEBAF cavity, originally designed for higher current storage ring application at Cornell, generates only a few tenths of a watt with the CEBAF beam which is small enough to be economically dissipated at the cavity temperature and within the cavity vacuum envelope avoiding the need for a window. In general, this is not the case and larger values of higher order mode power must be dissipated at some intermediate shield temperature or outside of the cryostat at 300 K. An example is the HOM extraction system developed at KEK which is shown.},
doi = {},
url = {https://www.osti.gov/biblio/791729}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Oct 01 00:00:00 EDT 1993},
month = {Fri Oct 01 00:00:00 EDT 1993}
}

Conference:
Other availability
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