Re: Screening for contaminated dosimeters

["Dale E. Boyce" <dale@radpro.uchicago.edu>]

We have occasionally seen spurious readings on badges.  Usually it
is some fraction of the many badges we get, but once several years
ago an entire shipment was fogged with an average of about 20 mrem
and it ranged from 10 to 50.

The most likely source is random coincidence putting the shipment of
badges near one of those Yellow II or III's that most air couriers
carry.

Check with your supplier to see if they always subtract controls off,
or if they only subtract them if the control reads in excess of some
threshold.  Even if they always suntract it, there is always a chance
that the control received less exposure than some of the badges.


Dale