Combating Nuclear Smuggling: Corruption, Maintenance, and Coordination Problems Challenge U.S. Efforts to Provide Radiation Detection Equipment to Other Countries. GAO-06-311, March 14
http://www.gao.gov/cgi-bin/getrpt?GAO-06-311
Highlights - http://www.gao.gov/highlights/d06311high.pdf

Combating Nuclear Smuggling: DHS Has Made Progress Deploying Radiation Detection Equipment at U.S. Ports-of-Entry, but Concerns Remain. GAO-06-389, March 22
http://www.gao.gov/cgi-bin/getrpt?GAO-06-389
Highlights - http://www.gao.gov/highlights/d06389high.pdf