DARPA may not have funded an instability study but, they sure bought a lot of it. I have two 1 meter by 10cm blanks of Zerodur. Unfortunately I don't have the lot pedigree or know the grade. They were lumped in with a lot I bought at DMRO auction in New Mexico about 10 years ago.
Just another life project waiting for the right amount Time, Materials, and Invar to complete. I'd love to have a couple of ~1500x200x100mm bars for an amateur LODTM (Large optical diamond turning machine). Talk about a bunch of Invar!!! Try holding +-50 nm for up to 120 hours! Jack -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Dr Bruce Griffiths Sent: Saturday, May 26, 2007 10:48 PM To: Tom Van Baak; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Pendulums & Atomic Clocks & Gravity Tom Van Baak wrote: I guess that DARPA didn't want to fund a study of dimensional instability that might span several decades. Zerodur is available in rod form (<4m length) from Schott: http://www.us.schott.com/optics_devices/english/products/zerodur/index.html? highlighted_text=zerodur You can even order it online. However it is relatively expensive as is most optical quality glass in these days of Lead, Arsenic, and Thorium free varieties. However It comes in several varieties some of which are more stable than others. It is best at constant temperature or at least stay below 130C for the standard variety. It makes nice ring laser gyros - widely used, at least before the advent of fibre ring laser gyros. _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
