Posted to CCD-world:
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On Sun, 28 Mar 1999, Gustavo Rahmer wrote:
> Posted to CCD-world:
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> Has anybody experience with contamination in vacuum (outgassing) coming from
> capacitors (ceramic, electrolytic, etc.) and also different ceramic types
> like NPO, X7R, Z5U?
Dear Gustavo
Refering to my posting to the list last December describing how the
plastisizer Di(2-Ethylhexyl) Phthalate (C24H38O4) was identified as the
contaminant of our CCD dewars - see:
http://www.cfht.hawaii.edu/~tmca/CCD-world/CCD-world.98.hypermail/0142.html
Quoting from the website http://www.nsc.org/ehc/ew/chems/diphthal.htm
the Chemical Backgrounder info on this substance: "As a non-plasticizer,
di(2-ethylhexyl) phthalate is used as a replacement for polychlorinated
biphenyls (PCBs) in dielectric fluids for electric capacitors."
I am sure the last word must read "eletrolytic capacitors" which would
make me reluctant to use any inside a vacuum. We have used Tantulum and
Ceramic capacitors inside the vacuum before, without any ill effects as
far as we could tell. Just be extremely careful never to apply reverse
polarity to a tantulum, I can only image the mess when blowing one up
under vacuum!
Regards
Willie
Mr. W.P. Koorts ( wpk at saao.ac.za )
South African Astronomical Observatory
PO Box 9 Observatory 7935 South Africa
Tel.(27) (21) 447 0025 Fax.(27) (21) 447 3639
World Wide Web ( Work ) http://www.saao.ac.za
World Wide Web ( Personal ) http://www.saao.ac.za/~wpk/
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