Re: Spurious TLD results

["Tony LaMastra" <alamastra@enter.net>]

As a comment on this and other postings about CRT's causing dose to TLD's -
the energy is usually low, around 20 to 35 kVp, and of low intensity.   It
should not have been interpreted as "high energy".   There is also the
other side of the coin - reporting low energy x-ray or beta dose, when
there is no exposure from these types of sources.   If the TLD is a true
crystal, is it possible a mechanical defect in the crystal can cause a
release of electrons on a random basis?   Or perhaps something similar to a
piezo effect?


Tony LaMastra
alamastr@enter.net

----------
> From: Ronald Frick <RFRICK@gammacorp.com>
> To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
> Subject: Re: Spurious TLD results
> Date: Friday, September 11, 1998 9:17 PM
> 
> The most recent dosimetry report for one of our hospital clients listed
an exposure of 60 to 70 mrem for everyone on the list.  The radiation
quality was recorded as high energy x-ray (above 250 keV effective) for
most of the badges.  Most of the individuals are x-ray techs and typically 
receive 'M' for their monthly dose, and would be expected to be exposed to
low effective energies.  The control dosimeters had not been returned with
the badges, so no correction could be performed.  When an investigation was
performed, it was discovered that the film badges had been left in a room
for approximately 1 week before being distributed to personnel, and that a
new computer monitor had been placed very close to them.   I would not
expect that this would cause the high readings.  Is this a reasonable
explanation for these readings?  Since they were not shipped back with
controls, another explation could be exposure in transit from some other
source.  We will be posing a badge next t!
> o the same monitor next month to try to reproduce the results.
> 
> Ron Frick
> rfrick@gammacorp.com
> 
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