Brad Dolan <bdolan@well.sf.ca.us> writes:

I think it would be interesting to try neutron activation analysis on currency. To do this, you would bombard the currency with neutrons and then look at the activated gamma spectrum to see how much of what odd trace materials might be present.

There are very sophisticated NAA scanners for luggage which can detect minute amounts of explosives. Despite prodding by the Feds, airlines have balked at forking over the hundreds of millions of dollars that would be required to install them at all airports.

I don't have any specific knowledge that the threads are "salted" for easy identification but this technique would work very nicely and has been used elsewhere.

While the technique works nicely on baggage, I think there would be some resistance to "neutron activation" of passengers. :) That is why I said in my last message that I knew of no method of remotely detecting currency carried by persons which was both inexpensive and posed no health risks. All RF techniques can be pretty easily defeated and NAA is not acceptable for use on living creatures. -- Mike Duvos $ PGP 2.6 Public Key available $ mpd@netcom.com $ via Finger. $