Most RTG sources use Plutonium 238 or Strontium 90. Primary decay component is Alpha particles which can be stopped dead by a few mm of shielding.
Good article on Wikipedia: http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator Dave > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of [email protected] > Sent: Friday, June 14, 2013 00:11 > To: [email protected] > Subject: Re: [time-nuts] Neat little cesium box > > Greg, > > the only power source I am aware off that can provide the ~5W power > required by that Novus box for 10-12 years with 20lbs weight > limit without any > external power sources or maintenance is a radioisotope > thermoelectric > generator (RTG) such as those used on Spacecraft. The > Russians used to use those > also in light houses. > > Maybe the atomic decay could be counted and used for > improving timing some > how?! > > That said the radiation would probably have a very negative > effect on any > electronics near it for long-term stability. I would also not > call that > solution "disposable" anywhere on earth. > > Definitely not hobby level stuff.. > > bye, > Said > > > In a message dated 6/13/2013 17:15:45 Pacific Daylight Time, > [email protected] writes: > > Tom, > > Thank you for your concern. I unfortunately cannot disclose > many details > about the proposed project only to say that the application > transcends much > of the typical "Time-Nuts" areas of normality. At present we are > evaluating typical frequency references to see if they will > fit into this project. > > What I can say is that phase noise is of little interest but > log-term > frequency drift is. The completed unit will unfortunately > not see GPS signals > during most of its lifetime, be constrained to a weight not > exceeding 20 > lbs, be considered non-recoverable (disposable) due to areas > of deployment > thereby require a relatively cost-conscious design, have no > access to a > source of power let alone any natural power-producing > resources and have an > expected lifetime of 10-12 years without maintenance access. > > Most of the problems have been solved including the power > source. This is > not your typical kitchen table project. And, as new > frequency references > are developed and the design feasibility phase is still > open, small and > minimal power-consuming products such as the Novus unit will > garner our > attention. > > Thanks for your offer, > > Greg > > _______________________________________________ > 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.
