EP contamination study by old MHI 9cell cavity

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EP contamination study by old MHI 9-cell cavity

• Jlab-FNAL-KEK S0 meeting
• 17 July 2009
• T. Saeki and P.V.Tyagi

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Scraping the contamination spot by scraper
Scraped the contamination spot by scraper.
An old MHI 9-cell cavity was EPed last week
after EP contamination was found.
A contamination spot was found inside
the beam-pipe of old MHI 9-cell cavity after the
EP.
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Sample preparation
Sample was set on Si wafer by silver paste.
0.5mm
Scraped contamination sample
Si wafer
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XPS analysis of scraped sample from old MHI
9-cell cavity
Nb-MHIcavity-contamination - as-received -
O
Only Nb, O, C were found on the contamination
sample, assuming Si is from Si wafer.
Nb
Nb
O
F
C
C
Si wafer
Si
Nb 11at O 48at C 27at Si 14at (substrate)
Nb, O
F, S, Al, Ag lt detection limit