AW: [ RadSafe ] TLD Readings in Checked Luggage

[Doug Aitken]

Thanks, Sandy:
Obviously, when a badged individual is receiving his dose in a fixed 
workplace, it is a lot easier. Unfortunately, in the oil patch, well 
logging and inspection personnel are moving around to a bunch of temporary 
workplaces. And these movements can involve both fixed-wing commercial 
flights and helicopter flights to offshore rigs. So they must carry their 
badges with them. We instruct our people to carry their dosimeters on them 
when travelling, rather than in baggage, and put them with their keys, 
etc., when passing through personal portals to avoid these doses. But of 
course, there are times when they forget, leave them in their hand baggage 
and pass them through inspection equipment. We even have a couple of cases 
where the inspection personnel would not let them leave them free from 
inspection and passed them through the scanner! (duh! highly trained and 
motivated security personnel working for little more than minimum 
wage......  What can we expect....)

We have a pretty good idea of the occupational exposure our personnel 
receive from the various procedures they do with sources, and every time we 
have what we consider an "abnormal" dose (by internal regulation, this is 
5mSv / 500mrem in any quarter) a rigorous investigation will be made, 
including analysis of all source manipulations AND air travel, to attempt 
to identify the cause. A number of cases have indicated that badges put 
through scanners here in the States (whether in checked baggage or hand 
baggabe) can give a significant dose of probably something more than 1 msv 
/ 100 mrem (but the actual amount from those exposures is no more than a 
"guestimate"

Regards
Doug

At 03:12 PM 9/6/2007, Sandy Perle wrote:
>Hi Doug,
>
>You pretty much said it all. What makes a dose attributable to the checked
>baggage scan is when the individual typically does not receive measurable
>exposure or not much more than minimum reportable from their routine
>occupational work where very little exposure is received. If an individual
>typically receives between 0.1 and 0.5 mSv each badging period, takes a trip
>and the dosimeter when processed reads 1.5 mSv, one can hypothesize that the
>exposure was due to the checked baggage scan. The higher the exposure that a
>worker receives, and especially if there is fluctuation in the exposure
>received from period to period, the actual quantity of exposure due to the
>checked baggage scan, will be difficult to determine. Yes, one would be
>aware of the fact that the X-Ray unit caused a dose, it just can't be
>quantified whereby the total dose on the dosimeter can be parsed, and an
>estimate used for the period where there was this non-occupational exposure.
>In the NPP there is always a secondary dosimeter worn along with the TLD or
>other dose of record dosimeter, and that can always be sued in lieu of the
>primary dosimeter.
>
>In conclusion, checked baggage X-Ray Scanners do put out a significant
>exposure, each and every time a dosimeter goes through one of them. If the
>individual never received dose or very little, one can subtract out the
>estimated scanned dose. If one typically receives higher doses that is
>variable, relying on the secondary dosimeter for the time occupational dose
>is received, assigning that, would be the most prudent thing. Trying to
>parse out a dose is nearly impossible, unless the dosimeter is only used for
>the specific trip in question.
>-----Original Message-----
>From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On Behalf
>Of Doug Aitken
>I'm not sure that this is totally correct, given the vast range of
>inspection equipment being used around the world, including heavy dose
>X-ray machines in some less up-to date places. In the US (I guess this is
>the focus of Linda's query), we have seen some higher than normal doses on
>TLD (L!7) and OSL (Al2O3) badges that have been attributed to airport
>security scans. However, as these are quarterly badges of workers
>performing source manipulations, it is a little difficult to attribute
>actual doses to airport exposures. Perhaps Sandy can give some more
>coherent information?

Doug Aitken                     Cell Phone    713 562-8585
QHSE Advisor
D&M Operations Support
Schlumberger Technology Corporation