“I know Bush was supposed to recognize the threat, but nothing came of any efforts.”
DNDO, DHS, TSA, and a host of commercial outfits actually did quite a lot in the area of detecting nuke threats. That’s where the ASP program came from, among several other systems.
Lots of basic research and engineering efforts were completed (I did some work looking at advanced scintillators like CeYAG and TlBr).
The fact that the results don’t get reported like NASCAR results is regrettable, but perhaps it’s better if the bad guys don’t know which highways have gamma scanners buried in the offramps.
I was involved in research to develop a low cost radiation detection system. What we ended up with was a detector (for under 2000 dollars) that could distinguish individual isotopes at 1/4 to 1/2 a mile. We had also developed a capability where these sensors would be networked (this is the portion of the project I was involved in) to do triangular location detection. The results were that we were actually able to locate a smoke detector at about 1/2 a mile. Obviously way too sensitive, but you could selectively “squelch” certain isotopes. Unfortunately, our funding was cut, as DHS decided to fund the big engineering companies for this project, to date, as I understand they are still light years behind where our research left off. It is a national tradgedy we were not able to continue our research efforts as we had truly gifted minds working on the problem. Along the way, we had also developed a “smart” shipping container (for less than 1000 dollars/per container) which would monitor a container (and nearby containers) to determine if there were any nasty cargo aboard the container, and to continuously update a centralized monitoring system.