Imagine being able to detect a radiation source no larger than a grain of sand, determine whether it's lethal 137cesium or the harmless potassium found in a banana in an instant while cruising past at street speed in a police Blazer.
Radiation detection devices called Adaptable Radiation Area Monitors, or ARAM, developed at California's Lawrence Livermore National Laboratory (LLNL), are mounted in the cargo areas in the back of SUVs called RadTrucks to take counterterrorism to the streets.
The ARAM devices are automatic portal monitors built to detect illicit low-energy gamma rays and neutron emissions characteristic of weapons-grade plutonium and highly-enriched uranium. The units are capable of providing accurate, positive warning and identification when suspicious materials come within detection range. Or, in the case of the RadTrucks, when the units come within range of the suspicious material. The New Jersey State Police has four RadTrucks. California also has a fleet of about 20 of the $200,000 vehicles. The Secret Service is also said to have one. Prior to Sept. 11, 2001, radiation portal monitors were used primarily to keep plutonium and uranium from being smuggled out of nuclear facilities, or to prevent contaminated scrap metal from entering industrial steel mills. The principle fear was that terrorists could use the contraband nuclear material to assemble a dirty bomb — a device designed to disperse radioactive contamination without the thermonuclear blast.
Even though a dirty bomb incident would be unlikely to cause many deaths, its real purpose would be to create instant terror in the form of mass panic, with lingering psychological damage. The aftermath would be as unpleasant as it is unprecedented. If a dirty bomb device were to be detonated in a crowded sports arena or holiday shopping mall, decontamination and treatment of potentially thousands of panic-stricken victims, as well as decontamination of affected areas, would be lengthy and expensive. A dirty bomb set off in a metropolitan setting would also render the contaminated area unsafe and unusable for weeks if not months, resulting in further commercial doom.
Having a speedy, reliable way to detect radioactive material, particularly while the source is in transit, has been the nuclear holy grail of homeland security officials for years. Yet, few protections exist today that can be readily installed into the stream of commerce to prevent dirty bombs and the materials for larger nuclear weapons from entering or leaving the country.
When earlier types of radiation detectors are put on the street they tend to alarm on harmless amounts of naturally occurring isotopes of potassium, radium, thorium and uranium — elements commonly found in commercial shipments and medical practices.
To avoid the nuisance alarms associated with real but non-threatening medical and industrial radiation sources, instantaneous isotope detection and identification is therefore mandatory for mobile applications. ARAM, licensed to IST-Textron Systems, accomplishes this in near realtime in the RadTrucks. Tests have demonstrated that detection passes are successful in less than 5 seconds at speeds of up to 50 mph.
ARAM provides detection and identification in one pass. "Previous generations of detection systems needed a first pass to detect a radiation source, followed by a second pass to identify the material," notes Dave Trombino, one of the Lawrence Livermore physicists that developed ARAM.
ARAM not only makes nuclear counterterrorism mobile, it makes radiation detection portable. "The 'A' in ARAM stands for Adaptable," Trombino says. "This detection system can be used in fixed locations, in mobile SUVs, on small boats or even in backpacks."
The New Jersey RadTruck project is part of the federally sponsored "Securing the Cities Initiative," a program that focuses on increasing terrorism readiness in the regions surrounding metropolitan New York City. The Defense Nuclear Detection Office within the Department of Homeland Security is the coordinating federal entity working to establish an enhanced level of preparedness in the Northeast, including the states of New York, New Jersey and Connecticut. The RadTrucks were provided to the New Jersey State Police as a key component to the early detection strategy.
So far, the trucks have been used to cruise metropolitan streets near the United Nations complex, around Flushing Meadows in New York City during the U.S. Open tennis championship, at football games at Meadowlands Stadium in East Rutherford, N.J., and at the presidential debate held at Belmont College in Nashville, Tenn., last fall before the election. "The mobile RadTrucks provide the ability to search for concealed radiation sources while on the move," says Textron spokeswoman Sharon Corona. "Now, we can go look for the threat instead of waiting for the threat to come to us."
ARAM technology is pretty good at going after the threat. ARAM is capable of identifying 30 microcuries of 137cesium — about the size of a granule of sea salt — from 10 feet away on the move. Textron says you'd need 500 times that amount of cesium to construct a dirty bomb, but if you had a dirty bomb, ARAM could detect and identify it from as far away as 120 feet — wider than an eight-lane highway.
Most radiation detection devices can be a challenge to master, but according to Capt. Dennis McNulty, executive officer of NJSP's Emergency Management Section, the RadTrucks can be operated by state troopers after only about 10 hours of training.
Ready, aim, wired
ARAM's automatic isotope identification relies on proprietary spectroscopic analysis software. Textron delivers the RadTrucks network-ready via wireless connectivity for extended reach-back support.
The trucks come equipped with touchscreen graphic interfaces and text message pagers. Modular system electronics and an integrated Pentium-based processor are housed in weatherproof, electromagnetic and radio frequency interference shielding enclosures that can be installed in any SUV platform.
Textron explains that ARAM uses a sodium iodide (NaI) device to detect gamma rays and a helium-3 (He-3) unit to detect neutrons. Both operate on the vehicle's 12-volt DC system. State-of-the-art signal processing allows ARAM to acquire 1,024 channels of data 10 times per second, which in turn allows higher probability of detection and provides the analytic software high-quality data for identification. The vehicles can be configured to include multiple detectors, as well as spectral data transmission and video capture. Current RadTrucks come outfitted with one or two NaI gamma detectors and up to four He-3 neutron detectors per vehicle.
Separate audio and visual alarms are provided for both gamma and neutron emissions through a simple Windows-based user interface. Vehicle emergency lights and sirens are also integrated into the RadTruck processor interface.
"This type of system gives us a better chance of not only picking up a radiation source, but also the type of radiation — whether it's a medical isotope or a terrorist device," says Trombino.
The tactical advantage of the RadTrucks is that they can be rapidly deployed based on changing intelligence. "Any border or port, any venue or event that might be a terrorist target can now be screened with minimal impact and interruption," he adds.
One significant operational advantage is it allows law enforcement to monitor for nuclear materials while performing routine police functions. Though the stated purpose of the RadTrucks is to provide a committed presence in the vicinity of the metropolitan areas of New Jersey outside New York City, the New Jersey State Police has assigned the vehicles to select divisions within the agency that have preexisting roles and responsibilities in homeland security, emergency response and transportation safety.
"Consequently, using thoughtful and deliberate deployment strategies, these personnel have the opportunity to conduct both routine patrols and pro-active radiation screening throughout the entire state, on a 24/7 basis," notes McNulty.
With technology this advanced, law enforcement can do its job while taking Homeland Security to a whole new level.
Douglas Page writes about science, technology and medicine from Pine Mountain, Calif. He can be reached at firstname.lastname@example.org.