Background Counting Using a Gas Flow Proportional Counter

[elizabeth_algutifan@wssrap-host.wssrap.com]

We have a gas flow proportional counter in our on-site laboratory that we use to
count air filters (environmental and work zone) for gross alpha/gross beta
activity.  Currently we count background overnight, Monday through Friday for a
total of 5 counts per week, but the frequency at which we will do them is not
specified in the laboratory QA Plan.  My question to those of you in counting
labs is this: Do you think it's necessary to do this many background checks? Is
there an applicable standard regarding frequency of background counting relative
to the numbers/activities of other samples we count (or other factors)? We'd
like to free up the instrument one night per week for another purpose.  I
appreciate all replies/advice on this subject.

Elizabeth Algutifan, 
Environmental Health Physicist
Weldon Spring Site Remedial Action Project
St. Charles, Missouri
Elizabeth_Algutifan@wssrap-host.wssrap.com
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