Guest blog from Dr. Christopher Smith, Director of S&T’s Transportation Security Laboratory
Every August, from the 19th through the 25th, the United States observes National Aviation Week. The week serves as a celebration of our nation’s long aviation history dating back to 1793 with the launch of a hot air balloon in Philadelphia, and notably, with George Washington in attendance. From that first launch to the historic Wright brothers flight in 1903 to present-day airplane travel, we commemorate all the achievements in between. Here at the Science and Technology Directorate’s (S&T) Transportation Security Lab (TSL), we’re celebrating National Aviation Week with a reflection on some of our own aviation technologies that keep the flying public safe and a look at how TSL continuously makes improvements to the Transportation Security Administration’s (TSA) ability to screen passengers, luggage, and cargo for explosives and other threats.
Primarily focused on civil aviation security, we conduct detection performance assessments and formal acceptance testing of technologies at all stages in the developmental lifecycle. Here are some of the projects that S&T and TSL are working on right now:
Building a Systems of Systems
Advanced Computed Tomographic (CT) systems can see and render three-dimensional objects inside of cluttered passenger bags with sufficient detail to identify material texture in addition to material density. Even with this capability, it is still possible to confuse certain explosive materials with some common benign objects. This inability to distinguish benign materials from explosives could lead to false alarms that must be resolved—often at significant expense to TSA and inconvenience to passengers.
With the support of S&T’s Baggage/Cargo/People Screening Program and partners Integrated Defense & Security Solutions and Halo X-ray Technologies Ltd., we have teamed-up to create a “system of systems” that ensure both high probability of explosive detection and a low false alarm rate. The system does this by using CT technology to identify all materials that could be threats and record their exact location within the concealing bag. This information and the bag are then passed on to an x-ray diffraction system which, though unable to efficiently scan the entire bag, efficiently interrogates the suspect item with the location information provided by the CT system. The combined information from the X-ray diffraction system and the CT system provides more clues to the nature of the suspect material and, hence, a greater ability to distinguish between benign materials and explosives.
The system is currently with us at TSL to collect data that will be used to train its very sophisticated automatic explosive detection algorithm. Once the algorithm is sufficiently trained, we will subject the system to a very rigorous testing that must be passed before TSA will commit to deployment.
Improving Passenger Experience
Though most of us recognize the need for thorough security screening at airports, none of us like the long lines, the need to divest, and intrusive secondary inspections. TSA, with TSL’s help, is trying to make transit through checkpoints faster and more pleasant; one way of doing this would be allow passengers to keep their drinks, medically essential liquids, and other fluids and gels in their carry-on bags. New checkpoint CT systems have the potential to inspect these materials, but on the occasions when these items alarm, TSA needs some means of resolving those alarms.
With TSA’s support, partners at Agilent Technologies and Rigaku Corporation are developing bottle liquid screeners to meet TSA’s needs. Before they can be deployed, TSL must test and certify these devices; preliminary assessments are occurring right now, and if the systems pass they will continue to the next phase of development toward eventual certification testing. Next up: walk-through passenger inspection systems, no-touch body alarm resolution, and walk-on shoe scanners!
Enhancing Cargo Screening Systems
Screening large pallets with x-ray imaging is inherently complex, as many kinds of cargo are often tightly bundled together on a single 48-inch square pallet. With Battelle Memorial Institute, we developed the Opacity and Complexity Assessment Software Tool (OCAST), which assesses real time cargo images to determine if they are too dense or too cluttered to allow for effective visual identification.
In the last fiscal year, TSL deployed an updated version of OCAST for assessments at four air cargo screening sites. The objective was to evaluate the operational impact of potential OCAST clutter thresholds on live stream of commerce cargo screening. Feedback from screeners suggest that the addition of the OCAST does not adversely impact screener performance. Moreover, the addition of OCAST did result in a significantly higher amount of cargo selected for secondary screening when the opacity/complexity of the cargo made it impossible to screen effectively.
Evaluating Metered Dose Trace Deposition Test Kits
TSL tests and evaluates new threat detections systems to TSA’s stringent detection requirements. Approved systems are then purchased and deployed by TSA, but the question remains of how long these certified systems will continue to meet TSA requirements as they age. After deployment, trace explosive threat detection (ETD) systems—systems that detect minute amounts of explosive residue of skin, clothing, and luggage items—have to be assessed periodically to ensure they are still capable of meeting detection requirements. To validate system performance in the field, system operators must place a precise quantity of a threat onto a sampling media to be interrogated by the ETD.
Procedures for performing this test were both inaccurate and unreliable until TSL developed a field-deployable metered dose trace deposition test kit based on inhaler technology to prepare samples for field verification.
These are just some of the ways that S&T and TSL are working to protect the traveling public without adding delays and hassle and aid the screening of cargo for dangerous and prohibited items without clogging transportation hubs. Much more information is available on the S&T website about our lab and ongoing work and S&T’s overall aviation security impact. We’ll also be sharing updates on our social media @DHSSciTech on all major platforms.
I hope you’ll join me in thanking the staff at TSL for all their great work…for these hard-working professionals, every week is Aviation Week.