Re: High dose for March

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

I haven't analyzed collective dose for this year, but in the past
I have.  As I remember in 1993 we had one month where we had
a great number of our badges with 10 20 or 30 mrem and some
higher for people who should have had a minimal exposure.  I
have seen this sort of thing on a smaller scale once in awhile.
Look at the distribution of exposures.   When I have seen this fogging
before it was usually confined to just a few series codes.  Only
once was it sufficient to raise the collective exposure of
the whole batch significantly.  We never have found an explanation.
I would guess we see some evidence of a few fogged badges about once
every year or two.  You should ask Landauer about their treatment
of the control badges.  I think they have a cutoff below which
they do not subtract the control's exposure from the batch.
Instead they just have an allowance for an average background.
If this were say 20 mRem above background and the whole batch
received 10 mRem of fog, then they might report some fraction
of the badges as having an exposure when in reality they are
at background when compared to the control.

You should not take my word for this.  This is just a hazy
memory of what I think they (might) do.

Good Luck!  Dale Boyce
dale@radpro.uchicago.edu