Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!hao!oddjob!uwvax!husc6!m2c!ulowell!cg-atla!mikkel
From: mikkel@cg-atla.UUCP (Carl Mikkelsen)
Newsgroups: sci.electronics
Subject: Re: electronic time capsule
Message-ID: <1901@cg-atla.UUCP>
Date: 25 Feb 88 15:49:30 GMT
References: <3a623999.44e6@apollo.uucp>
Reply-To: mikkel@cg-atla.UUCP (Carl Mikkelsen)
Organization: Compugraphic Corp. Wilmington, MA
Lines: 33

In article <3a623999.44e6@apollo.uucp> nelson_p@apollo.uucp writes:
> I got the following suggestion on how to
> time out all those years before awakening:
>
>> try radioactive decay for timing.  Inherently stable, easy to count,
>> small, low power.
>
>  What materials would have a sufficiently short half-life to be suitable?  

	Try tritium, like was used in the old TI backlit LCD watches.

>  How can I sense the radioactivity?

	If you used a TI-like back-lighting module, you could sense
	the radiation with one of several photon (not alpha, beta, or
	gamma) detectors.

>  Are there reliable solid-state detectors?

	I would think that a good phototransistor should be as
	reliable as any other semiconductor device.

>                                      --Peter Nelson

	- Carl

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