[ RadSafe ] Radiation Doses to Luggage

[Bob Westerdale]

Hi-
        Back in the 80's I was a tech for Philips, who built many of the 
early baggage X-Ray systems.  We started with a basic 'flood beam' 
approach that used the full beam from the tube with little collimation or 
filtering. You put the bag in the big lead box, and created the radiograph 
using a fluorescent screen and a low light TV system.     X-Rays stayed on 
for as long as you held down the 'On' button, so the bag relieved a dose 
proportional to that period.  Later systems ( the more familiar 
conveyor-based ones you see today) collimated the beam down to a stripe 
about 1/4" wide, which struck a long strip of photodiodes capped with an 
X-Ray fluorescent material.  The  frame storage electronics  collected the 
signals as the bag passed through the narrow X-Ray beam.   Final testing 
on each unit included a Dose-per-Inspection check,  ( ion chamber ) which 
was typically around .1 mR  per pass.   These were safe for film up to 
about ASA 1000,  and we could see 28 gauge wire and at least 12 shades of 
gray.   I'm surprised to hear of the much higher doses for checked 
baggage, perhaps they are x-raying the whole cargo container full of 
suitcases and hence need more flux......    I got a call one morning from 
the North Slope of Alaska, where a couple pipeline workers had been snowed 
in at the local airport.  They spent the night amusing themselves by 
running each other through our machine,  with no observable health 
effects. (AFAIK!)   The security supervisor was unable to tell exactly how 
many passes were made through the machine, but he was quite surprised to 
see a human silhouette on the TV monitor when he came to work that 
morning!
        cheers,
                Bob Westerdale
 
 



Sandy Perle <sandyfl at earthlink.net> 
Sent by: radsafe-bounces at radlab.nl
03/09/2005 08:54 AM

To
Floyd.Flanigan at nmcco.com, elsa.nimmo at varian.com, radsafe at radlab.nl
cc

Subject
RE: [ RadSafe ] Radiation Doses to Luggage






Floyd,

Very much so. The units in foreign airports have even higher outputs in 
some cases. My data is based on actual dosimeters, film and TLD, that were 
placed in checked bags.

I am about to board another flight, 1st of 2 today, for my hormetic dose 
:)


-- 
Sent from my PalmOne Treo

-----Original Message-----
From:  Flanigan, Floyd
Date:  3/9/05 8:43 am
To:  Sandy Perle, elsa.nimmo at varian.com, radsafe at radlab.nl
Subj:  RE: [ RadSafe ] Radiation Doses to Luggage

Sounds like their x-ray equipment is very different from ours. Ours takes 
a 'snap-shot' of the contents as they pass through the array and is only 
in the 'on' position for a split second. The picture it puts out is very 
detailed, in color and shows stratification of object throughout it's 
layers. I guess the dose is varried depending on the equipment/model etc.

Floyd W.Flanigan B.S.Nuc.H.P.

-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl]On
Behalf Of Sandy Perle
Sent: Tuesday, March 08, 2005 7:20 PM
To: elsa.nimmo at varian.com; radsafe at radlab.nl
Subject: Re: [ RadSafe ] Radiation Doses to Luggage


On 8 Mar 2005 at 9:23, Elsa Nimmo wrote:

> Does anyone know of recent studies reporting the range of radiation
> doses that a piece of checked luggage might receive per one pass
> through security screening at an airport?  It would be great to find a
> study that included info worldwide, but leads on more limited studies
> are welcome too.

Checked bags X-ray units for the most part put out high dose. 
Dosimeters irradiated in these units approaches between 150 and 300 
mrem in many instances. Kodak has an alert about outting your film in 
checked bags.

These units are not typical check units and these are different than 
he units used to check carry-on bags, which have a lower output.

-------------------------------------
Sandy Perle
Senior Vice President, Technical Operations
Global Dosimetry Solutions, Inc.
2652 McGaw Avenue
Irvine, CA 92614 

Tel: (949) 296-2306 / (888) 437-1714  Extension 2306
Fax:(949) 296-1902 

E-Mail: sperle at dosimetry.com
E-Mail: sandyfl at earthlink.net 

Global Dosimetry Website: http://www.dosimetry.com/ 
Personal Website: http://sandy-travels.com/ 

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