Group led by Stanford physicist says there's an urgent need for nuclear ...(out some suspects. Nuclear forensics ca...)

Nuclear forensics can make a difference, May said in an interview.

But the U.S. capacity for such investigations has deteriorated since the end of the Cold War, when the capabilities were well supported at the nuclear weapons laboratories. Presently available trained personnel are highly skilled, but there are not enough of them to deal with an emergency and they are not being replaced, according to May. A program to refill the pipeline of trained personnel should be undertaken.

Theres also a need for development of new equipment, both in the lab and on the street, which could provide a faster analysis during a crisis. The authors also recommend more coordination between scientists and law enforcement; even simple steps such as trading phone numbers could prove crucial. You really want the top decision makers to know where to get information, May said.

The remnants of an atomic explosion carry a host of clues, even at the microscopic level, including crystal structures and impurities.

Uranium, for example, varies in isotopic composition and impurities according to where it was mined and how it was processed. Weapons-grade plutonium can be exposed during its production to different neutron fluxes and energies, depending on the particular reactor used. It is also possible to establish the length of time plutonium spent in the reactor.

In some cases, it may be possible for scientists at Lawrence Livermore National Laboratory or Los Alamos National Laboratory to use their experience, intelligence data and software codes to reverse-engineer a nuclear bomb from its debris and learn telltale details of the design of the explosive.

These clues would not be the equivalent of fingerprints or DNA, May said, but would in most cases allow officials to at least rule out or in broad classes of possible sources.

Tracing bomb material to its source may be only the beginning of an investigation, rather
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