It takes about 30 to 60 seconds to track enough muons for each cargo container screened, Morris said. There have been questions on whether the method is quick enough to allow prompt screening of large numbers of vehicles or cargo containers. "We've been fighting the general perception that there are not enough muons to measure," Morris said. "There really are." The team is developing better software techniques to allow rapid 3-dimensional images of the volumes being screened. They can reliably detect a small cube of uranium - about 4 inches on a side - within a large metal container full of sheep.

While the Los Alamos research is still in its developmental phase, Morris said he is confident a muon detectors, probably at an initial cost of about $1 million each, could make a significant contribution to efforts to tighten screening of vehicles and cargo containers entering the United States.

This AAAS session was organized by Rick Chartrand of the Los Alamos National Laboratory.

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19-Feb-2005