Re: Particle & Nuclear Physics for HS Teachers

[Wes Davis <wlrdavis@EARTHLINK.NET>]

Vickie Frohne writes:

> 5R is the max. legal annual dose for
> a radiation worker

    A minor quibble:  the max permissible dose is 5.0 REM -
not Roentgen  -  but her comments were right on target.

    Wes


-----Original Message-----
From: Frohne, Vickie <VFrohne@BEN.EDU>
To: PHYS-L@lists.nau.edu <PHYS-L@lists.nau.edu>
Date: Friday, August 23, 2002 3:11 PM
Subject: Re: Particle & Nuclear Physics for HS Teachers


> 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