http://edl-inc.com/datasheetPDFgallery.php
For example. Unless you are doing fundamental physics research, are you sure you need a cryo temperature standard? -John ============== > Hi > > Yes, indeed you can buy or rent a calibrated RTD. You might be able to > rent a quartz thermometer. The HP version (2804) has been history for > quite a while. In both cases they come with a cute little disclaimer on > the accuracy that more or less says: > > "We can't be sure that this stays calibrated through the shipping process, > a triple point cell must be used to verify calibration at the use > temperature". > > One of the reasons HP dropped the product was that people discovered that > need after it had been in production for a quite a while. Hysteresis in > the LC cut crystals turned out to be one of several issues that > contributed to the problem. > > Pretty much *everything* with a triple point down at 190K is going to have > something nasty about it. > > Bob > > On Jan 26, 2013, at 3:57 PM, "J. Forster" <j...@quikus.com> wrote: > >> You can't be serious. Ammonia gas or liquid is dangerous. >> >> You can buy calibrated RTDs or rent a quartz thermometer and stay alive. >> >> YMMV, >> >> -John >> >> =============== >> >> >>> Hi >>> >>> If the intent is to come up with a triple point cell to calibrate your >>> thermometer, acetone's triple point (at 178.5K) is a bit low. I still >>> think I'd go with ammonia. >>> >>> Bob >>> >>> On Jan 26, 2013, at 2:51 PM, Graham / KE9H <time...@austin.rr.com> >>> wrote: >>> >>>> On 1/26/2013 1:29 PM, Paul Amaranth wrote: >>>>>> Message: 4 >>>>>> Date: Sat, 26 Jan 2013 16:28:19 +0100 >>>>>> From: Fabio Eboli <fabi...@quipo.it> >>>>>> To: Discussion of precise time and frequency measurement >>>>>> <time-nuts@febo.com> >>>>>> Subject: Re: [time-nuts] OT, looking for a good science forum >>>>>> Message-ID: <5ef3f142b075fcab38182666a4e50...@quipo.it> >>>>>> Content-Type: text/plain; charset=UTF-8; format=flowed >>>>>> >>>>>> Il 2013-01-26 14:58 Bob Camp ha scritto: >>>>>>> Hi >>>>>>> >>>>>>> Platinum RTD's are a pretty good bet for -80C, they hold up well >>>>>>> down >>>>>>> there. For calibration, ammonia and acetylene both have triple >>>>>>> points >>>>>>> in the vicinity. I'd probably try ammonia first, but not for any >>>>>>> good >>>>>> Doesn't acetylene have a bad habit of dissociate when pure liquid? >>>>>> >>>>>> Fabio. >>>>>> >>>>> Yes, it's normally stored disolved in acetone. It also spontaneously >>>>> dissociates >>>>> if pressures exceed 15 psig or 30 psi absolute. That could put a >>>>> real >>>>> damper on your day. >>>>> >>>>> >>>> Just pure acetone works well at dry ice temperatures. We used crushed >>>> dry ice >>>> in acetone as an alternative when the liquid nitrogen truck was late >>>> making its delivery >>>> for the cryro lab. >>>> >>>> --- Graham / KE9H >>>> >>>> == >>>> _______________________________________________ >>>> 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. >>> >>> _______________________________________________ >>> 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. >>> >>> >> >> >> _______________________________________________ >> 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. > > _______________________________________________ > 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. > > _______________________________________________ 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.