Sophisticated Screening

Trace detection aids in thwarting advanced terrorist techniques

Traditionally, aviation security checkpoints have focused on searching for metallic items and explosives using walk-through metal detectors and X-ray technology. However, as terrorists become more sophisticated, the need for better explosive-detection technologies that can detect an increasing variety of threats, including improvised explosives materials such as triacetonetriperoxide, is emerging.

Historical and recent events have shown that the threat of explosives and improvised materials to aviation security continues to increase. Trace detection provides the capability of detecting invisible particles smuggled onto aircraft by passengers in carry-on and/or checked baggage. If a threat substance, such as an explosive device, is hidden, it is impossible to see, smell, hear, touch or taste it. Trace detection technology enables the analysis of the particle contamination left behind or emitted by that substance.

Limitations of Physical Analysis
Historically, physical analysis at security checkpoints minimized these potential threats. However, no single technology can provide a comprehensive detection solution at a checkpoint. This point was highlighted by the Richard Reid incident, the shoe bomber who attempted to bring down American Airlines Flight 63 with an improvised explosive device that contained a plastic explosive with a TATP trigger. The TATP is organic peroxide with base ingredients that include acetone, bleach and drain cleaner. These basic ingredients can easily be purchased without attracting any attention. It also is believed that peroxide-based explosives were used in the July 7, 2005, London bombings.

The use of trace detection has become a preventative measure that can be employed across a wide spectrum of checkpoint applications. As we look to implement a total screening solution in the aviation sector, explosive trace detection technology has become an integral part of that solution and can complement X-ray machines, CT scanners and walk-through metal detectors by resolving alarms and providing confirmation once a suspected threat is found.

Being Obvious
One of the most efficient ways of deterring the smuggling of explosives across security checkpoints is by screening passengers and their carry-on luggage in an overt and efficient manner. Positioning the ETDs directly after the X-ray systems or CT scanners is typically most convenient for airport screeners. Checking the external surface of laptops, electronic devices and a carrying case is much faster, less obtrusive and leads to a higher throughput than requiring passengers to switch them on.

Arguably, the critical part of ETD technology is how the samples are collected and transferred by the screeners. Swipes or swabs are the most common method of sample collection. They are used to collect samples for direct insertion into the ETD analyzer. The technology is based on the belief that when concealing explosives in a bag, the terrorist or bomb carrier is bound to leave traces of the explosive material on parts of the bag. As a result, screeners concentrate their sample collection efforts on handles, zips, locks and items like MP3 players, digital camera and laptops.

Checked Baggage Screening
The Transportation Security Administration requirement for 100 percent screening of all checked baggage will become the standard in the aviation industry. Due to high false-alarm rates, typically experienced by explosives detection systems, ETD is often used as a complementary technology to resolve potential EDS alarms.

The combined use of EDS and ETD equipment is one of the most effective methods to identify suspect items of checked baggage and carry-on items. Checked baggage identified as suspect by EDS systems are set aside for further inspection using ETD technology.

Narcotics Trace Detection
The security industry is seeing the emergence of ETD devices that incorporate dual-detection capabilities of both explosive and narcotic substances, which address the rising global terror threats as well as the growing trafficking of contraband and illicit substances. These additional capabilities are now common in airports and at border control and customs checkpoints. It is becoming an essential tool for airport customs officials as a result of its ability to provide them with the operational capabilities needed to stay ahead of growing narcotic trafficking activities, while maintaining the reliable explosive detection capabilities and low false-alarm rates.

SDT recently introduced its MN1000B, a dual-mode explosives and narcotics trace detection system that builds on the success of the company’s range of trace detectors and is based on the advanced high-frequency quartz crystal microbalance, which incorporates dualmode detection capabilities in a single unit. It is nonradioactive and based on a green technology that can detect and identify a wide range of explosives, improvised materials and illicit substances while maintaining the highest levels of sensitivity and selectivity and maintaining low false-alarm rates.

According to Airport Council International, the number of global passengers is forecast to surpass 5 billion by 2010, and by 2025, it is expected to be in excess of 9 billion passengers globally. Air cargo and freight operations are expected to grow faster than passenger operations, with the number of tons expected to triple by 2025. This rise in passenger throughput, air cargo and freight places additional pressures on the aviation security industry, which is already facing multiple, complex challenges and threats. The most prominent of these threats is global terrorism. The aviation security industry must adapt to the evolving nature of the threats and, as such, ETD systems will undoubtedly become more prominent within airport security checkpoints around the world. To cope with the growing demands, ETDs will become smaller, lighter and more portable. In addition, they will have greater connectivity—whether using Bluetooth or WiMax technology— to airport control centers.

This article originally appeared in the March 2009 issue of Security Today.

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