Re: TLD badge dose

[Brian Rees <brees@LANL.GOV>]

I've seen a whole bunch of folks with TLD readings higher and lower than 

this for checked luggage.  I've been told that with the CAT scan type 

machines, it depends on how the "stripe" hits the TLD, so if it's 

multi-chipped there may (or may not) be a wide disparity between TLD chips 

in the badge.  1.4 mSv is a reasonable value for what I've seen.  It's 

kinda ironic, for years we've been conditioning folks to not put them in 

carry-on luggage, now we need to re-condition folks.

At Los Alamos we ended up putting notes on all TLDs to remind people what 

to do with TLDs when they travel.  People aren't supposed to take their 

routine TLDs on travel with them, we issue a travel TLD and control and 

specific instructions.



Brian Rees



At 11:37 AM 1/9/2004 +0000, David Hornsey wrote:





>    Good morning Radsafe,

>

>        An X-ray thickness gauge manufacturing company I work for in the UK

>sent three engineers to San Diego for training on a particular rig. All took

>the TLD badges they were issued with here. Unfortunately the Company they

>were working with in San Diego did not issue them with local monitoring.

>They all carried out similar work whilst in the States, but one of them came

>back with a badge reading of 1.4 mSv. The others nothing. On interviewing

>them, the only difference I could discover was that the one who got the dose

>had the badge in his suitcase whilst the others carried them on their

>person. The guy with the dose attributes the exposure to what he said was

>the very strict baggage surveillance now being practiced at American

>airports, particularly he commented at San Diego. I was sceptical because to

>get 1.4 mSv in the seconds it must take to scan a suitcase with X-rays

>implies a very significant dose rate from the unit. He did comment, however,

>that he was requested to open the case because they had picked up something

>they considered needed visual examination, so they probably scanned it more

>extensively.

>        So - is such a dose feasible for suitcase surveillance or could

>anything in the baggage compartment of a 'plane result in an actual dose or

>an artefact? Obviously not a real problem dose-wise unless it continues to

>show up on his badges, but any thoughts would be most welcome to satisfy

>both his and my curiosity.

>

>   David Hornsey

>

>Radiation Safety

>South Building Annexe

>University of Bath

>Bath BA2 7AY

>01225 386540

>e-mail:bssdjh@bath.ac.uk

>

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