Nuclear detectors tested in Nevada desert.

The Department of Homeland Security's newest office--dedicated to stopping a nuclear attack on U.S. soil--has begun testing detection devices at ranges in Nevada.

The Domestic Nuclear Detection Office, established in April of this year, inherited the project, known as the Advanced Spectroscopic Portal program, from the Homeland Security Advanced Research Projects Agency.

HSARPA in 2004 awarded contracts to 10 companies, calling for the development of detectors that can discriminate between naturally occurring radioactive materials and ingredients that could be used to create a nuclear device. Those contracts have been transferred to the DNDO.

The companies have provided prototypes of the detectors that they would like to sell to DHS. DNDO began testing them in August at the Radiological and Nuclear Countermeasures Test and Evaluation Complex at the Nevada Test Site, near Las Vegas, according to Vayl Oxford, acting director of the program. Testing is expected to continue through the end of this month.

Successful vendors will be asked to begin low-rate production of detection systems to be deployed at the U.S. borders with Mexico and Canada.

The portal program is among the first concrete steps taken by the new office. The DNDO is part of DHS Secretary Michael Chertoff's effort to reorganize his department to focus upon the most serious threats to U.S. security.

The office will be staffed with DHS technicians and nuclear-detection experts from various state and federal agencies, Oxford said. Cooperation between the office and the various other agencies involved in the counter-nuclear proliferation is voluntary.

Detecting a nuclear device within U.S. borders is not the way that DHS wants to deal with such a threat, Oxford said. The preferred method would be to seize the nuclear material abroad, before it enters the United States, he said.

The DNDO "will not undermine" those efforts, but he cautioned that the United States "cannot rely on that alone."

The portals are just one segment of a massive, worldwide effort to track illicit nuclear materials and keep them away from American soil. Oxford outlined a future counter-nuclear plan with the ability to fuse detection data and intelligence assessments in near real-time.

That effort requires coordination with allied countries, as well as other U.S. agencies, such as the Departments of Defense and State Department, and the FBI, he said.

Coordinating with so many players is a serious challenge, Oxford said. The problem of systems integration alone "is of biblical proportions," he said.

As DHS envisions the process, for example, every detection at a land crossing would be reported to a central collection point for analysis. Not only does this place increased demands on computer networks, but it also complicates design requirements for engineers working on the frontline equipment.

One key requirement is to minimize false alarms, which could cause a flood of useless data, reducing confidence in the systems and damaging international trade. Many harmless items, such as cat litter and granite tiles, can trigger radiation detectors. With the massive amount of cargo and vehicles being scanned, even very low false-positive rates could translate to large numbers of pointless searches and data crunching.

Another problem is the ability of some dangerous materials to slip through a technology net.

Highly enriched uranium is a serious nuclear-terrorism threat, because its stocks are more plentiful, less secure and easier to use than plutonium, Oxford said. Unfortunately, he added, it also emits a weak radiation trace, posing a large challenge to detectors.

The testing in Nevada is intended to discover equipment that can detect the real threats, even with a weak signal, Oxford said.

"All the technology solutions will be validated through what we can claim are high fidelity testing and evaluation ... before any acquisitions are made," he said.

The next generation of detectors has to be easy for people with little technological training to use. "I believe the burden [of nuclear safety] will fall on federal, state and local law-enforcement personnel," Oxford said. "We have to bring radiation detectors to their daily lives and daily operations."

Strategic decisions need to be made concerning where detection devices would be used. While land bridges and seaports are obvious sites, other places--such as major cities and infrastructure--also would need protection, he said.

"The establishment of these sites obviously will be risk responsive and risk prioritized," he said. For example, he explained, Washington, D.C., and New York City are tempting terrorist targets and would be high on a priority list for detectors.

Even if commercial technology was up to the tasks required by DNDO, Oxford said, adapting it for homeland security poses an engineering challenge. "With commercial-off-the-shelf products, you end up deploying 100 systems," he said. "We need one system with 100 protection elements."

In addition to the portal program, the DNDO is working to develop other technologies to establish a synthesized, real-time monitoring system.

More requests for proposals are expected by the year's end, including one for Cargo Advanced Automated Radiography Systems, designed to automatically check cargo with new signatures so that terrorists cannot shield illicit materials. Another request will focus on high-tech, handheld devices for use by Border Patrol agents in the field and other law enforcement officers on land and at sea.

Longer-term goals include a quest for better standoff-detection gear, Oxford noted. Next-generation equipment needs "to better enable a broad range of detection, especially in search and surveillance," he said.

The DNDO also sees great promise in new materials, such nano-enhanced or superconductive fibers, which can be molded into lightweight containers with improved detection properties.

Oxford said that the potential impact of even a small nuclear attack on U.S. soil has forced the government to pour resources into thwarting such an event. "If we're in clean-up mode, we have failed miserably."