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Title: High gradient superconducting niobium cavities: A review of the present status

Abstract

Superconducting niobium cavities used in particle accelerators are limited in their rf performance by two phenomena: quench field levels below the theoretical limit of the material caused by defects, and field emission loading resulting from artificial contamination of the superconducting surfaces during surface treatment and assembly procedures. In recent years, the community involved in SRF technology developments has successfully improved cavity performances by applying advanced surface treatment methods such as chemical polishing, electropolishing, tumbling, high temperature heat treatment, high pressure rinsing, ``in situ'' high peak power processing, and clean room assembly procedures. In addition, improvements in the material properties such as thermal conductivity by ''solid state'' gettering'' and very strict QA methods, both in material inspection and during cavity fabrication, have resulted in cavity performance levels of E{sub acc} up to 40 MV/m in monocells and gradients in the vicinity of 30 MV/m in multicell structures at Q-values of {approx} 10{sup 10} at a temperature of 2K. More recently the fabrication of ``seamless'' cavities by spinning is being pursued with encouraging results. This process eliminates electron beam welds, which sometimes are the causes of performance degradations.

Authors:
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility, Newport News, VA (US)
Sponsoring Org.:
USDOE Office of Energy Research (ER) (US)
OSTI Identifier:
755347
Report Number(s):
DOE/ER/40150-1444; JLAB-ACT-98-07
TRN: US0002430
DOE Contract Number:  
AC05-84ER40150
Resource Type:
Conference
Resource Relation:
Conference: Conference title not supplied, No location, No date; Other Information: PBD: 1 Sep 1998
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; RF SYSTEMS; ACCELERATORS; SUPERCONDUCTING CAVITY RESONATORS; NIOBIUM; QUENCHING; FIELD EMISSION; SURFACE TREATMENTS; PERFORMANCE; TECHNOLOGY ASSESSMENT

Citation Formats

Peter Kneisel. High gradient superconducting niobium cavities: A review of the present status. United States: N. p., 1998. Web.
Peter Kneisel. High gradient superconducting niobium cavities: A review of the present status. United States.
Peter Kneisel. Tue . "High gradient superconducting niobium cavities: A review of the present status". United States. doi:. https://www.osti.gov/servlets/purl/755347.
@article{osti_755347,
title = {High gradient superconducting niobium cavities: A review of the present status},
author = {Peter Kneisel},
abstractNote = {Superconducting niobium cavities used in particle accelerators are limited in their rf performance by two phenomena: quench field levels below the theoretical limit of the material caused by defects, and field emission loading resulting from artificial contamination of the superconducting surfaces during surface treatment and assembly procedures. In recent years, the community involved in SRF technology developments has successfully improved cavity performances by applying advanced surface treatment methods such as chemical polishing, electropolishing, tumbling, high temperature heat treatment, high pressure rinsing, ``in situ'' high peak power processing, and clean room assembly procedures. In addition, improvements in the material properties such as thermal conductivity by ''solid state'' gettering'' and very strict QA methods, both in material inspection and during cavity fabrication, have resulted in cavity performance levels of E{sub acc} up to 40 MV/m in monocells and gradients in the vicinity of 30 MV/m in multicell structures at Q-values of {approx} 10{sup 10} at a temperature of 2K. More recently the fabrication of ``seamless'' cavities by spinning is being pursued with encouraging results. This process eliminates electron beam welds, which sometimes are the causes of performance degradations.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Sep 01 00:00:00 EDT 1998},
month = {Tue Sep 01 00:00:00 EDT 1998}
}

Conference:
Other availability
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