Re: Landauer's New Badge

[jrflood <bflood@SLAC.Stanford.EDU>]

>Regarding the new Landauer TLD discussion, the availability of new data
>regarding your ALARA program should be reason enough . . .

Just because something CAN be done doean't always mean that it SHOULD be
done. Changing to a system yielding 1-digit doses instead of a 10 mrem
theshold will almost certainly cost a company money to retrain staff to
ubderstand the change, even if the more sensitive dosimeter service is no
more expensive to the customer. In exchange for its investment, what dose
the company get?

If the company makes no changes to workplace activities or configurations
because of the new information (i.e., doesn't take actions to eliminate the
single digit doses), then it has incurred a startup cost for the new
dosimeter and then makes no use at all of the additional detail in the dose
data. All cost, no benefit.

Is it reasonable to claim to make workplace changes to reduce individual
exposures by less than 10 mrem per quarter? Attempting to do so would convey
a message that such small doses are something for a worker to fear or be
concerned about. I believe that claiming to have prevented a dose equal to
1/1000 of the dose limit over a monitoring period is suspicious at best,
and, given what can be shown with any reliability, completely unjustified.
How much should an employer spend to reduce a 5 mrem dose to less than 1
mrem? In my opinion, not one cent.

If you suspect that some workers are receiving doses near the reporting
threshold and are concerned about the cumulative masking effect, then a
longer monitoring period would be more appropriate, i.e., changing from
monthly to quarterly or from quarterly to semi-annual or perhaps
tri-mesters. The frequency of processing for exposure control would never be
an issue for such monitoring since the question would be about whether the
doses being measured are 10 mrem or less, nowhere near a level requiring
close attention to prevent overexposure.

Aluminum oxide is an excellent environmental dosimeter because it yields so
much light per mrem when processed. This imposes a limitation, too,
however - the higher light output per mrem also means that the
photomultiplier tube that counts the light output will reach its performance
limitations (deadtime, tube shock, etc) at a correspondingly lower dose. So,
switching to a dosimeter that can provide a reporting threshold that is an
order of magnitude smaller will also bring with it an order of magnitude
smaller upper limit for performance, which means it may not be able to
provide adequate measurments in case of an accidental exposure. Everyone
hopes and even expects that won't happen to them but, should one give away
the ability to measure a potentially life-threatening dose in an accident
situation to obtain an improved precision at low doses, even though the
improved precision isn't particularly useful?

I think it would be prudent for an HP to show his/her company management
what the new dosimeter can do, and determine if the company would take any
action (i.e., spend its money) in response to a 5 mrem dose where it has
been reported as zero or M in the past. If the company's answer is No, then
there's no reason to change. If a company would spend its money to eliminate
or reduce a 5 mrem dose, then the data provided by the dosimeter would be
used for something.


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