Trust me on this, as poorly the public image of the CIA has become, it is only to the advantage of our foriegn intelligence personnel.
The worlds supply of all nuclear weapons material is strictly accounted for. Any attempt to smuggle a TND into one of our ports is very remote without our people knowing about it.
As far as the need for this billion dollar radar detector, it's just another BS story. We already have many undisclosed methods of detecting any radiological materials or devices but they are deeply classified.
The bottom line here,is for people to quit hyperventilating over this port issue. It is not a major big risk deal like it is being made out to be.
The Gamma-Ray device Customs uses is called VACIS.
Here is the website of the vendor:
http://www.saic.com/products/security/mobile-vacis/
Here is an article on US Customs' own site from 2000 stating they're using these things.
http://www.cbp.gov/custoday/mar2000/hitec.htm