I've played with cryogenically coolled Thermal imagers (yes as a hobby, but work too). and LN2 has a lot going for it. It's cheap and does not wear out (as stirling cycle and peltier coolers do) and is safer than high pressure pure air. That reminds me I've a source for some 24V pure air compressors that were used for TOW sights ;-) Robert G8RPI.
--- On Mon, 1/12/08, Lux, James P <[EMAIL PROTECTED]> wrote: From: Lux, James P <[EMAIL PROTECTED]> Subject: Re: [time-nuts] Voltage standards To: "M. Warner Losh" <[EMAIL PROTECTED]>, "[email protected]" <[email protected]> Date: Monday, 1 December, 2008, 12:45 AM On 11/30/08 4:27 PM, "M. Warner Losh" <[EMAIL PROTECTED]> wrote: > The thing that got me was the word 'really' in Bruce's statement. It > read like someone who had tried it, had limited success, but in the > end wound up believing that while possible, it wasn't really > practical. After thinking that, I couldn't imagine that somebody on > the list hadn't tried it for some reason or another over the years. > > After all, as you say, a fine bottle of scotch isn't that expensive > when it comes to the pursuit of your obsessions :) > > Warner And surely, with these grim economic times, liquid helium dewars are going to be popping up on the surplus market. Then, at least, you'll have a place to store that liquid helium. And speaking of cryogens, has anyone on the list done cryogenic sapphire ring oscillators? (at home) After all, folks at JPL are doing this " We present design progress and subsystem test results for a new short-term frequency standard, the Voltage Controlled Sapphire Oscillator (VCSO). Included are sapphire resonator and coupling design, cryocooler environmental sensitivity tests, Q measurement results, and turnover temperature results. A previous report presented history of the design related to resonator frequency and frequency compensation [1]. Performance goals are a frequency stability of 1×10-14 (1 second ≦ τ ≦100 seconds) and two years or more continuous operation. Long-term operation and small size are facilitated by use of a small Stirling cryo-cooler (160W wall power) with an expected 5 year life." http://hdl.handle.net/2014/39769 Seems that running a cryocooler is probably a bit easier than pouring liters of liquid helium into a cryostat. Jim _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
