Researcher Eric Szarmes discussed a set of accelerators with Pui Lam. These accelerators are part of a powerful electron beam laser that is being assembled at Watanabe Hall at the University of Hawaii.

UH to devise
nuclear-test detector

By Mary Vorsino

As the nation bolsters its defense against the threat of nuclear or biological weapons, a group of University of Hawaii researchers has received $50 million to develop a portable sensor to detect clandestine nuclear weapons testing.

The team eventually hopes to broaden the sensor's capabilities to scan baggage or cargo at America's airports and harbors for molecular traces of explosives or hazardous chemical agents.

Principal investigator for the project is UH-Manoa physics and astronomy professor John Madey. He and his team were recently awarded the grant by the Nuclear Treaty Program Office to research the project over five years.

The sensor, described by Madey as a "molecular bar-code reader," could continually test the air for nuclear particles that would have been dispersed into the atmosphere by a nuclear explosion -- even if the explosion was underground.

The treaty office hopes to have 400 of the portable devices around the world in seven to 10 years, Madey said.

Shot through a tube filled with water from the Ala Wai, glowed blue as the laser light interacted with the suspended organic material. Processes based on similar principles can help identify and locate a wide variety of materials in the atmosphere with a wide range of applications from ecological monitoring to military defense surveillance.

"It will be something that we can move from site to site," or from airplane to barge.

Co-investigators in the project include UH-Manoa professors Eric Szarmes, Shiv Sharma, Pui Lam, Paul Lacey and Chester Vause.

Szarmes, who worked with Madey as a graduate student in the early '90s, said, "People are concerned about detecting these things (nuclear and chemical hazards)."

And since the Sept. 11 attacks and subsequent terrorist threats, the importance of this and similar types of security-oriented research has amplified, he said.

The team recently spent the last of a $6.2 million grant it received in 1999 from the Department of Defense for the same proposal.

The idea behind the research is relatively simple, said Madey, who is surprised that the Hawaii researchers were the first to stumble over the landmark concept.

"This works on the basis of imaging rather than physically collecting these particles." It could provide near instantaneous analysis as the data comes in.

Using a free electron laser -- a light source capable of generating intense infrared and ultraviolet radiation -- the sensor would scan air particles and be able to distinguish radioactive isotopes (slightly different versions of the same atom) from their benign cousins and alert monitoring stations to any airborne radioactive molecules.

Madey invented the free-electron laser in the '70s when he was a California Institute of Technology graduate student.

Current nuclear testing sensors can take upwards of a week to collect data because they collect particles that have drifted downward from the atmosphere.

Once collected, the particles still need to be analyzed, which can take up to three days.

"In a week, the air current can change so that it's really hard to tell where these traces might come from," Madey said.

Lam, the team's theorist, said that each isotope has a "fingerprint" of sorts and that the painstaking research involves finding out how to program a laser to recognize the different atoms accurately, and how to make the laser portable enough for easy transport.

A now-empty concrete- and steel-encased room (called the test cell, formerly a machine shop) in UH's physics and astronomy building, Watanabe Hall, will soon be home to the two free-electron lasers assigned to the research team.

The researchers will also use additional lasers and equipment sprinkled in eight labs throughout the campus for information gathering.

The team expects the weapons sensor prototype to be operational in two to three years and will begin testing it at the Navy's Pacific Missile Range Facility at Barking Sands on Kauai in 2006 or 2007, Szarmes said.

The laser sensor technology has a wide range of possible spin-off applications, Madey said. Not only could the laser be used to screen baggage and ships' cargo, but it could monitor environmental conditions and air quality more accurately and rapidly than current sensors, he said.

Of the team's grant, $3 million will go towards other possibilities for the free-electron laser sensor -- chiefly security screeners that could detect not only nuclear particles but chemical and possibly even biological hazards.

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