RE: Alpha contamination survey meters

["Abelquist, Eric" <AbelquiE@orau.gov>]

Jack-

In my experience, it is not humanly possible to detect 10 to 20 dpm alpha
with a frisk or clearance survey.  You would be doing well to detect ten
times that with a frisk.  For static smear counting you may approach 10 to
20 dpm, but you'd be counting for a while.  Most smears for alpha are
counted with a gas proportional counter in a lab setting - and 10 dpm is
easy to achieve in 2 minutes.

Anyway, the detectors routinely used for alpha measurements include ZnS and
gas proportional (set on alpha plateau) - both only respond to alpha/

Regards
Eric Abelquist
abelquie@orau.gov 

-----Original Message-----
From: Chadwick, Jack [mailto:JxC2@pge.com]
Sent: Thursday, March 09, 2000 1:58 PM
To: Multiple recipients of list
Subject: Alpha contamination survey meters


I am interested in recommendations for a portable alpha contamination survey
instrument and probe capable of accurately detecting 10 - 20 DPM on a smear
or a direct frisk. The instrument must not have a response to beta or gamma
radiations. The instrument will be used for unconditional release of
equipment and personnel, so the response time needs to be tolerable for
personnel frisking. If anyone has a positive experience with an instrument
matching these characteristics I would appreciate your feedback.

Jack Chadwick
Humboldt Bay Power Plant

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