Re: 'Dirty Bomb' Was Major New Year's Worry

["Gerald Nicholls" <Gerald.Nicholls@dep.state.nj.us>]

Something doesn't make sense here.  Looking for a nuclear weapon with a

neutron sensitive detectionn system makes sense, but you wouldn't want

to look for a "dirty bomb" with it.  While it might be possible to make

a dirty bomb using a neutron source, it would be difficult to find

materials for it and to disperse them.  It's far more likely that

someone would construct a dirty bomb using Cs-137, Sr-90, Co-60, or

Ra-226.  It's possible but more unlikely that someone would use a

collection of medical radioisotopes or even a huge number of Am-241

smoke detector sources.  None of these emit neutrons and hence a microR

meter and a GM meter would be the instruments of choice.



A dirty bomb based on sources from a large number of moisture-density

gauges might be an exception to the above but it would still emit gamma

radiation if both sources from the gauge were used. 



Gerald Nicholls



>>> "Kim D. Merritt" <k.merritt@larc.nasa.gov> 01/08/04 08:14AM >>>

Do not underestimate their instrumentation.  They are designed to look

for 

weapons not radiographers, and I would not expect radiographers to be 

congregating in public areas with their sources.  In any event, if they



detected a radiography source it would (hopefully) be accompanied by a



person authorized to be in possession of it so it would not show up as

an 

anomalous event.



At 11:06 PM 1/7/04, you wrote:

>I saw some of the detectors on the TV and they didn't appear very 

>sophisticated.

>

>If they were really digging for radioactivity hot spots, how did they

miss 

>all the radiographers who carry large cobalt and Iridium sources to

and 

>from pipeline and refinery sites in the Houston area.



Kim Merritt

Radiation/Laser Safety Officer

HazMed, Inc.

NASA Langley Research Center

Hampton, VA

(757)864-3210

<mailto:k.merritt@larc.nasa.gov>



Disclaimer: The views and opinions expressed herein are my own and do

not 

necessarily state or reflect those of NASA or the United States

Government, 

nor do they represent the official position of NASA.



************************************************************************

You are currently subscribed to the Radsafe mailing list. To

unsubscribe, send an e-mail to Majordomo@list.vanderbilt.edu  Put the

text "unsubscribe radsafe" (no quote marks) in the body of the e-mail,

with no subject line. You can view the Radsafe archives at

http://www.vanderbilt.edu/radsafe/ 





************************************************************************

You are currently subscribed to the Radsafe mailing list. To

unsubscribe, send an e-mail to Majordomo@list.vanderbilt.edu  Put the

text "unsubscribe radsafe" (no quote marks) in the body of the e-mail,

with no subject line. You can view the Radsafe archives at

http://www.vanderbilt.edu/radsafe/