Apparently there are also concerns that the ability to produce crystals in glass enclousres going forwards may be in doubt as the required industrial base continues to shrink.
----- Original Message ---- From: Chris Caudle <ch...@chriscaudle.org> To: time-nuts@febo.com Sent: Wednesday, September 16, 2009 8:15:14 PM Subject: Re: [time-nuts] Fundamental limits on performance > From: Mark Spencer <mspencer12...@yahoo.ca> > For anyone who is interested here is a bit more info about the USO's used > in deep space applications and some comments abou the crystal based USO's I found it interesting that one of the limits of stability seems to be the ability to process the crystals at high temperatures to drive off impurities. The JHU crystals are apparently in some type of glass enclosure which can take the high temperatures, and the paper seemed to indicate that the standard metal capped packages can't take the higher temperatures. I had forgotten until I read that paper that Fox has crystals which are packaged in quartz packages. I couldn't find any information on how the packages are assembled, so I don't know if the assembly process could handle the higher temperatures, but obviously if the package really is pure quartz, it should be able to handle temperatures as high as the quartz resonator. I would assume that the package is in two parts, and has contacts that penetrate the lower part of the package to connect the resonator to the surface mount pads on the bottom surface of the package, so it might depend on how the penetration is sealed, and how the top and bottom parts of the package are attached together. Just seemed interesting, I would assume that the JHU guys know about those types of advances in packaging, but the paper didn't mention it. -- Chris Caudle _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. __________________________________________________________________ Looking for the perfect gift? Give the gift of Flickr! http://www.flickr.com/gift/ _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
