Characterising unknown waste drums

[Ninni Jacob <njacob@gsosun1.gso.uri.edu>]

Does anybody out there have any good ideas for characterising lab waste in
a drum, assuming there are only gamma emitters present?  This is also
assuming that it is a non homogenous mixture, and it is difficult to get a
representative sample to count.

Do you still try to get as good  a sample as possible? or?

One method is to  count the drum on a Ge-li detector, while the drum
is being rotated.
Then dose rates have to be taken at eight different points outside the drum.
Then one has to apply all kinds of efficiency, geometry, tau,  and density
factors and come up with activities for different isotopes.  This is a very
time-consuming process. After all, we are talking about "waste".
How close do the estimates have to be? Within a microcurie? Within
hundreds of microcuries? Remember, the final results are expressed as
curies on the shipping paper.

 Any ideas are welcome.

Ninni Jacob
Radiation Safety Officer
University of Rhode Island