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Re: Radioisotope generators



Bob: The problem I have experienced with the "Minigenerators" is that the
Cs-137 slowly leaks out, reducing the useful activity to useless amounts in
time. We use metal planchettes to hold the liquid (only about 10 drops of
eluting solution is required), and let it evaporate if we observe the
Cs leakage, tape over the planchette, and store these small Cs sources to
decay away. The question I have - is it legitimate to simply flush this
small amount of Cs into the sink (dilution is the solution to polution!),
or should we continue to keep the planchettes? (The activity measured
with a thin-window G-M tube can be as much as a few hundred cpm.)

This problem is one reason I got around to publishing the paper, "The Hot
Balloon (Not Air)" in TPT,Vol.33, pp344-345, Sept. 1995, in which an
effective activity of about 45 min can be extracted from the air. This
is still a useful time frame to use, and at least it's always there.

For more info - check out the article "Radioactive balloons: experiments
on radon concentration in schools or homes" in Physics Education, Vol 32,
pp97-100, March 1997 and also my earlier paper "Radioactiveball" in TPT,
Vol. 30, pp 16-17, Jan. 1992.

This same 45-min activity can be obtained much more reliably by the old
fashioned way of simply filtering dirt out of the air with an air
blower/ShopVac/etc. for about an hour or two. In fact, I am presenting a
paper on this procedure at the Denver meeting in August, showing typical
results.

Tom Walkiewicz walkiewicz@edinboro.edu
Department of Physics http://www.edinboro.edu/~Walkiewicz/home.html
Edinboro University office: (814)732-2468
Edinboro, PA 16444