Re: 120-ml and tool monitor

["William E. Cox" <COXWX@naesco.com>]

Typically, these monitors are set up with a point source efficiency to monitor
loose surface contamination on materials.  Some facilities have done shielding
calculations and bounded cases where these monitors are even used to look for
internal comtamination.

There is nothing to say that one could not set one of these up with an
efficiency for a liquid geometry.  Based on my experience I estimate you could
achieve about a 1e-5 uCi/ml (2700 dpm total) MDA for Cs-137 in a 120ml sample
within the units maximum 100 second count time.  This assumes a four detector
SAM9 unit in a <10uR/hr background using a Prob of Det of 1S and a Prob of False
Alarm of 2.4S.  Therefore it could be done but you may not be able to meet your
ODCM specified values.  Obviously some specific application testing would be
required and some assumptions made about the average gamma mix.  Mark Deacon at
Bicron/NE could tell you who is doing this.

Bill Cox
Seabrook Station HP
coxwx@naesco,com


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