From: John De Armond
Subject: Re: Bomb detection
Date: 28 Apr 93 16:17:04 GMT
Christopher Brian Cox <firstname.lastname@example.org> writes:
>The only good 'device' I know of is fast neutron analysis (NOT thermal
>neutron - which is slightly more accurate than guessing). Unfortunately
>most people object to even small amounts of neutron irradiation. :-)
Neutron activation analysis would never be done on the person simply because
there are too many other easily activated elements present in the body.
Nitrogen is somewhat difficult to activate in sufficient quantities
to read before it decays. Other methods work just as well anyway.
Both liquid and gas chromatography work very well. Even wet chemistry
has been refined enough for color indicators to be sensitive down in
the fractional PPM range. The bomb sniffers used at airports and nuclear
plants use selective absorption and re-emission of nitrate ions and
are sensitive enough to detect a nitroglycerin angina patch and even
powder residue on a shooting jacket after a long day at the range.
(as I discovered one day when entering the TMI facility.)