Nuclear Detection Tech: Airborne Sensors for NYC?

[hammertime]

So I posted this in a few other forums, but I thought that this would be a good place to get even more feedback. Sorry, mods.

Does anyone here know what developments are being made in nuclear detection technology? Is there anything like, say, an airborne sensor that can detect the tiniest amount of highly enriched uranium, even if its shielded behind a large amount of lead, in a bustling metropolis like NYC from thousands of feet in the air? Are any developments being made towards that kind of technology?

 

[vanesch]

Please don't double-post. If everybody starts to do that, we get a hell of a mess here.

As to your question, well, in order to be able to detect something, you have to have at least something that reaches your detection platform. Enriched uranium is not a very active substance, and unfortunately it is not an emitter of very hard gamma radiation. So I don't see how you could ever be detecting the presence of enriched U that is properly shielded from a large distance. Enriched U contains essentially U-235 (and also some U-234), and both of them are essentially alpha emitters (undetectable at a distance of more than a few micrometers) and gamma emitters but rarely, and they are soft gammas (below 1 MeV).

 

[Enthalpy]

A suggestion I read recently was to put a short-range detector in each mobile phone, in order to get a full coverage.

Anyway, more and more people realize that bombs are not missiles, and that the last bombs were dropped by propeller planes and the next ones will travel in a container and take a lift. So shooting missiles down doesn't protect against bombs, and better means would be welcome. Agreed.

 

[Morbius]

A suggestion I read recently was to put a short-range detector in each mobile phone, in order to get a full coverage.

Anyway, more and more people realize that bombs are not missiles, and that the last bombs were dropped by propeller planes and the next ones will travel in a container and take a lift. So shooting missiles down doesn't protect against bombs, and better means would be welcome. Agreed.

Enthalpy,

Radiation detectors in cell phones are already under development. Here's a news release from
5 years ago from Lawrence Livermore National Laboratory:

https://publicaffairs.llnl.gov/news/news_releases/2003/NR-03-04-06.html

• RadNet, A Cellular Telephone-Based Radiation Detector Network: Under development for six months,
RadNet is based on small detector units that will feature the capabilities of a cell phone, radiation sensor,
Personal Digital Assistant, Internet access and a Global Positioning System locator."

However, I have to agree with vanesch; if the nuclear device is shielded - so radiation can't escape;
which is fairly easy to do; especially with a U-235 fueled device; you can't detect radiation that can't
get to your detector - no matter how sophisticated the detector.

Former UCLA Chancellor and former Professor of Nuclear Engineering Dr. Albert Carnesale made a
speech while he was UCLA Chancellor in February 2002 entitled "Rethinking National Security":

http://www.ucnuclearfree.org/articles/2002/02/22_carnesale_rethinking-national-security.pdf

From the bottom of page 13:

We must also address the security of our borders. For example, the cargo containers that come into our
country every day -- by ship, by rail and by truck -- are large enough to hold many nuclear weapons. A
nuclear weapon could fit in the trunk of your Toyota. You don't need a cargo container.

The threat of nuclear terrorism is very real; and is being worked on.

Dr. Gregory Greenman
Physicist