Re: Particle & Nuclear Physics for HS Teachers

["Frohne, Vickie" <VFrohne@BEN.EDU>]

Beware of surplus geiger counters unless you know what you're doing. Many of
them have radioactive "check-sources" attached, which may not be desirable
in a high school environment. I've seen some pretty "hot" sources on surplus
geiger counters (although not the yellow civil defense models), and once you
buy them, it's nearly impossible to get rid of them legally. With any old
geiger counters, the calibrations will be questionable. The other thing
about the yellow CD geiger counters  is that some models (actually
ionization chamber counters)are so insensitive that you could get a lethal
dose before anything would register on 'em. The dosimeters in the CD kits
usually go from 0 to 200 Roentgens, when those issued to radiation workers
usually read 0 to 200 MILLI-Roentgens! (5R is the max. legal annual dose for
a radiation worker, and enough to cause serious radiation sickness if
absorbed all at once.) The CD dosimeter chargers are usually pretty good,
though.
     For high school student use, you can get new geiger counters for around
$200 from Vernier. http://www.vernier.com They can be used either with the
Vernier computer interfaces & Logger Pro software, or as stand-alone
counters.  Vernier also has a book of experiments to go with their counters.

Vickie

-----Original Message-----
From: William Beaty [mailto:billb@ESKIMO.COM]
Sent: Friday, August 23, 2002 3:46 PM
To: PHYS-L@lists.nau.edu
Subject: Re: Particle & Nuclear Physics for HS Teachers


On Fri, 23 Aug 2002, macisaac wrote:

> Right now I'd like to obtain Geiger counters for these teachers -
> supposedly civil-defense era counters are available from somewhere
> cheap, though I have yet to find where.

Try eBay.  People are always selling groups of several counters.  I think
that was an old civil defense package, with three counters (one with a
probe, two with internal GM tubes), a bunch of radiation badges, and a
badge resetter.  The price usually goes to around $70 for those sets of
three if you watch them for many days, so if the price for three goes far
higher than $70, wait for the next batch.  Try these:


http://cgi6.ebay.com/aw-cgi/eBayISAPI.dll?ViewSellersOtherItems&userid=telep
hone-trading-post

http://cgi6.ebay.com/aw-cgi/eBayISAPI.dll?ViewSellersOtherItems&userid=misc.
electronics


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