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Title: INVESTIGATION OF "HOT-SPOTS" AS A FUNCTION OF MATERIAL REMOVAL IN A LARGE-GRAIN NIOBIUM CAVITY

Abstract

Poster - The performance of a single-cell cavity made of RRR > 200 large-grain niobium has been investigated as a function of material removal by buffered chemical polishing. Temperature maps of the cavity surface at 1.7 and 2.0 K were taken for each step of chemical etching and revealed several 'hot-spots', which contribute to the degradation of the cavity quality factor as a function of the RF surface field, mostly at high field levels. It was found that the number of 'hot-spots' decreased for larger material removal. Interestingly, the losses of the 'hot-spots' at different locations evolved differently for successive material removal. The cavity achieved peak surface magnetic fields of about of 130 mT and was limited mostly by thermal quench. By measuring the temperature dependence of the surface resistance at low field between 4.2 K and 1.7 K, the variation of niobium material parameters as a function of material removal could also be investigated. This contribution shows the results of the RF tests along with the temperature maps and the analysis of the losses caused by the 'hot-spots'.

Authors:
;
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility, Newport News, VA
Sponsoring Org.:
USDOE - Office of Energy Research (ER)
OSTI Identifier:
895307
Report Number(s):
JLAB-ACC-06-585; DOE/ER/40150-4138
TRN: US0700439
DOE Contract Number:  
AC05-06OR23177
Resource Type:
Conference
Resource Relation:
Conference: 2006 Linear Accelerator Conference (LINAC 06), 21-25 Aug 2006, Knoxville, Tennessee
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; CHEMICAL POLISHING; ETCHING; HOT SPOTS; LINEAR ACCELERATORS; MAGNETIC FIELDS; NIOBIUM; PERFORMANCE; QUALITY FACTOR; REMOVAL; TEMPERATURE DEPENDENCE

Citation Formats

Gianluigi Ciovati, and Peter Kneisel. INVESTIGATION OF "HOT-SPOTS" AS A FUNCTION OF MATERIAL REMOVAL IN A LARGE-GRAIN NIOBIUM CAVITY. United States: N. p., 2006. Web.
Gianluigi Ciovati, & Peter Kneisel. INVESTIGATION OF "HOT-SPOTS" AS A FUNCTION OF MATERIAL REMOVAL IN A LARGE-GRAIN NIOBIUM CAVITY. United States.
Gianluigi Ciovati, and Peter Kneisel. Mon . "INVESTIGATION OF "HOT-SPOTS" AS A FUNCTION OF MATERIAL REMOVAL IN A LARGE-GRAIN NIOBIUM CAVITY". United States. https://www.osti.gov/servlets/purl/895307.
@article{osti_895307,
title = {INVESTIGATION OF "HOT-SPOTS" AS A FUNCTION OF MATERIAL REMOVAL IN A LARGE-GRAIN NIOBIUM CAVITY},
author = {Gianluigi Ciovati and Peter Kneisel},
abstractNote = {Poster - The performance of a single-cell cavity made of RRR > 200 large-grain niobium has been investigated as a function of material removal by buffered chemical polishing. Temperature maps of the cavity surface at 1.7 and 2.0 K were taken for each step of chemical etching and revealed several 'hot-spots', which contribute to the degradation of the cavity quality factor as a function of the RF surface field, mostly at high field levels. It was found that the number of 'hot-spots' decreased for larger material removal. Interestingly, the losses of the 'hot-spots' at different locations evolved differently for successive material removal. The cavity achieved peak surface magnetic fields of about of 130 mT and was limited mostly by thermal quench. By measuring the temperature dependence of the surface resistance at low field between 4.2 K and 1.7 K, the variation of niobium material parameters as a function of material removal could also be investigated. This contribution shows the results of the RF tests along with the temperature maps and the analysis of the losses caused by the 'hot-spots'.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2006},
month = {8}
}

Conference:
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