Re: Emissions from Televisions

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

The story I heard about x-rays from a couple of independent sources
was that all of the x-ray hoopla originated from a last minute
design change of a specific television set in the early days
of color sets.  It seems that the manufacturer found a cheaper
source for a high voltage rectifier.  Normally the HVR was housed
in a metal box, but the boxes had already been stamped and bent.
The new tube was slightly taller than the original design.  To avoid
losing money on getting new housings made, a hole was cut allowing
the top of the tube to stick through.  X-rays were emitted, but the
highest doses were behind the set.  The glass on the front of the set has
always been thick enough to prevent x-ray emission, primarily so
that the relatively flat surface can withstand the pressure difference.

The last time I checked the regs, tv's were permitted up to 0.5 mrad
at the surface.  However, I have never seen one that was measurable
with a thin window GM or thin NaI probe.  Although, I have seen
old survey instruments that would react a little bit to the non-ionizing
emissions.  If memory serves, and this was quite a few years ago, we
verified this by removing the probe and still saw needle fluctuations.

For the purposes of the interview you might point out that the
use of the word emissions in this partricular context implies
non-ionizing radiation.

Dale Boyce
dale@radpro.uchicago.edu