Radioactive sources

[Douglas Sinclair <dsinclai@acs.ucalgary.ca>]

Yup, the 3 microcurie source makes sense.  With a pair of diodes we could 
make the detector 4 pi, but no big deal.  3 microcuries is not a problem
health-wise as long as you don't eat it.  As it's an alpha source, any shiledingor even a few centimeters of air will stop the rays.  Howerver, I just encountered a new angle on it.  According to my father, that's on the order of $100
worth of radium :(.  If we're willing to go with a much slower source, we can
use thorium which is only $2 per gram or so.  Alternativly, anyone have 
an old clock with a radium dial? <grin>

BTW: Cosmic ray background is only 1 event per square foot per minute.  Plus,
they occur in showers.  So that isn't going to work. 

-- 
Vercotti: I was terrified of him.  Everyone was terrified of Doug.  I've seen
          grown men pull their own heads off rather than see Doug.  Even
          Dinsdale was frightened of Doug.
Interviewer: What did he do?
Vercotti: He used sarcasm.  He knew all the tricks, dramatic irony,
          metaphor, bathos, puns, parody, litotes and satire.
			-- Monty Python, Episode 14
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