Next-Generation, Layered Security Screening

by David W. Cullin

Security checkpoints help law enforcement officers enhance public safety by detecting chemical, biological, radiological, nuclear, explosives, and other threats. With advancements in multiplexed luminescence technologies, the detection of trace amounts of explosives can expand beyond stationary checkpoints using handheld tools that are cost-effective and simple to use.

Of the potential chemical, biological, radiological, nuclear, and explosives (CBRNE) threats faced by law enforcement, the threat from explosives is pervasive. Modern security checkpoints provide an opportunity to detect, interdict, and deter the use of an explosives threat. Desktop explosives trace detectors (ETDs) are broadly deployed in checkpoints due to their ability to detect invisible amounts of explosives quickly. However, they are plagued with high false-alarm rates and time-consuming maintenance.

Although critical to public safety, checkpoints operate with some level of predictability, which make them more vulnerable to CBRNE threats. Mobile trace detectors provide the opportunity to introduce random screening protocols that increase the likelihood of threat detection. Until recently, law enforcement did not have access to a handheld tool capable of detecting a broad range of explosives threats at true trace levels. Recent technological advancements provide performance upgrades and cost advantages that will make ETD tools accessible to more first responders, adding a new layer of protection to security screening. 

More Accurate Fixed-Site Screening Tools A variety of complementary explosives detection technologies are currently used in checkpoints to address both visible (bulk) and invisible (trace) explosives threats. They range from X-ray and colorimetric indicators to ion mobility spectrometry (IMS) and canines. Trace residue can be left behind on first-touch areas such as bags, cellphones, mass transit cards, personalentification cards, and event tickets. Trace residue found on surfaces can indicate contact with actual explosives or incendiary devices. Desktop ETDs are widely deployed as the last line of detection for many screening checkpoints. When bulk threats have been eliminated using other technologies like millimeter wave or X-ray systems, a desktop ETD presents a final chance to detect invisible amounts of explosives. 

Desktop ETDs provide high-fidelity threatentification and are designed to quickly screen a high number of items per day. They are best-suited for permanent installations, where the security infrastructure can support extended use. IMS-based desktop trace detectors are widely deployed in security screening checkpoints due to their speed of detection and sensitivity. One of the challenges with IMS technology, though, is a high number of false alarms. Each alarm must be resolved to determine if a true threat is present. IMS technology also requires both weekly and monthly maintenance. Not only do these deficiencies negatively impact throughput and tie up resources, these first-generation technologies struggle to keep pace as adversaries adapt their tactics and introduce new explosive threat materials.

In recent years, mass spectrometry-based desktop trace detectors have been introduced specifically to address these concerns in security screening missions. Mass spectrometry brings the accuracy and confidence of laboratory instrumentation to the field, significantly reducing the potential for false alarms in operational environments and providing an enhanced layer of security. Mass spectrometry technology has an inherently larger library capacity over IMS technology. As new threats are realized, the library can expand without negatively impacting existing sensitivity or false alarm rate.

Manufacturers have placed an emphasis on simplifying the user experience and eliminating data interpretation typically associated with lab-based instrumentation to minimize training and deployment costs. To further lower the cost of ownership, recent mass spectrometry-based product introductions have reduced maintenance to just a few hours per year. This is a significant improvement in system operational availability and helps reduce operational costs.

Mobility as the Enemy of Predictability  Handheld ETDs are commonly used by the military. However, the need for next-generation ETD solutions extends beyond the battlefield. Although fixed-site checkpoints are critical to safeguarding lives, they can also present a level of predictability that is probed by extremists for weakness. Trace detectors that are mobile help law enforcement randomize their interdiction efforts and bring the deterrent to the threat, adding an enhanced layer of security beyond the fixed-site checkpoint. Finding the explosive is important and can prevent one explosion; however, finding the bomber, bomb maker, or the weapons cache has a larger effect in security applications. Random checkpoints, temporary roadblocks, or foot patrol can uncover trace evidence that can be used to seek bulk explosives threats and defeat a terrorist. Trace evidence collected during mobile missions fills in the intelligence picture and increases the likelihood of detecting a threat.

Multiplexed luminescence technology field-proven by the military fills this capability gap in the law enforcement tool kit. This technology enables handheld trace detectors to provide broad threat detection with best-in- sensitivity in an ultra-lightweight form factor for maximum portability. It offers the ability to detect threats in less than ten seconds, so officers can quickly complete their screening mission. Products are now being fielded that feature on-screen guidance, simple go/no-go alarms, and on-device video training that provides real-time help and reduces the cost and logistical burden of recurrent training. An emphasis on ergonomic design and durability has resulted in highly portable tools that support a mobile mission. For the first time, handheld explosives trace detectors capable of the trace detection mission are available for under $10,000.

Upgrading the Future of Security Screening ETD technology has advanced significantly in recent years due to focused investment by the CBRNE community. As a result, higher-performing sensors are accessible to more first responders. These tools are designed to expand deployment scenarios, simplify daily operations, and reduce costs. With increased budget constraints, manufacturers have focused more than ever on producing affordable sensors. Recent technology advancements and product innovations have broken price barriers, allowing handheld explosives trace detection to truly become a key capability in the future of policing.

Checkpoints soon will be equipped with next-generation screening tools that are designed to address shortcomings of existing technologies, with increased accuracy, ease of use, and lower cost of operation. From interdiction missions to actionable intelligence, the deployment of next-generation handheld and desktop ETDs will provide an added layer of security that maximizes coverage and disrupts the explosives threat.


David W. Cullin is the vice president of research, development and programs for FLIR Detection. Previously, he served for seven plus years in the U.S. Department of Defense's Chemical and Biological Defense Program. As the Director of Technology at the Joint Program Executive Office for Chemical and Biological Defense, he focused on new technology that would help the U.S. armed forces counter weapons of mass destruction. Before that, he directed the DOD Critical Reagents Program and led the technical team in the development of what is now the Department of Defense's (DOD) Portal Shield BW detection system. He joined the Defense Department in 1991, as a research chemist with the Naval Surface Warfare Center in Dahlgren, Virginia, after earning his Ph.D. in Chemistry at The Ohio State University.