Technology
Explosives Screening by MS
What it means for homeland security.
In 2003, the US National Academy of Sciences published a report to Congress and the Transportation Security Administration entitled “Opportunities to Improve Airport Passenger Screening with Mass Spectrometry,” (National Academies Press, Washington DC, 2003). The principal conclusions and recommendations from that report were that (i) ion mobility spectrometry (IMS) cannot meet current, let alone future threats, (ii) that mass spectrometry (MS) has 10-10,000 times greater resolving than IMS, and that (iii) TSA and DHS should begin developing and deploying mass spectrometry (MS). The report also mentioned Syagen Technology, as a leader in MS detection of explosives.
Interestingly just about every major industry that requires accurate chemical analysis (e.g., pharmaceutical developers, environmental monitoring, forensics, food and beverage quality control, clinical diagnostics, etc.) has already adopted MS as the gold standard for chemical analysis, because it offers superior performance when compared to other chemical analysis methods. In fact, no other major industry uses IMS for chemical identification, only the security industry. The reasons for this relate to the aviation security industry’s historical need for an inexpensive, mobile detector, at a time when security was not a huge priority and the terrorist threat to the aviation industry was low. Also, not until recently have MS based security detection instruments become available.
Syagen has developed a powerful, automated MS screening system for explosives and other threat compounds such as toxic chemicals and chemical and biological weapons. In 2007 Syagen launched its first commercial explosives screening system, the Guardian explosives trace detection portal. The Guardian Portal provides an improved alternative to older IMS based portal systems used in airports today and helps to close the security vulnerability gap; from concealed explosives carried on people.
The MS and IMS detection technologies offer a sharp contrast in capability for the security professional. The MS can operate on a wide range of explosives which include current terrorist threats from improvised explosive compounds, while IMS detects a rather limited range of explosive targets (16 explosives compounds that are constituents in dozens of explosives devices vs. about 5 explosives compounds for IMS). Additionally, MS technology offers a fundamental molecular resolution a factor of 10 -100 times greater than that of the IMS portals. This leads to far fewer false detections with MS technology, versus the much lower resolution IMS which has difficulty making distinctions between harmless chemicals and explosive compounds. Unfortunately, IMS cannot always discriminate between target molecules and interferent chemical compounds, even though it is used in mission critical roles where airline passengers lives depend on an accurate security screening.
So, it is not of great comfort to know that the only detection technology currently employed at US airports, utilizes only IMS trace detection technology!
The Challenge of Personal Screening
Effective methods of securing airports and airlines exist today. Every checked bag is screened using a sophisticated tomography technology (EDS) and backed up with a swipe based trace detection (ETD). All carry-on bags are screened at the checkpoint by x-ray devices and people are screened by metal detectors. However, the aviation security’s greatest vulnerability is from suicide bombers where individuals are carrying concealed explosives on their bodies.
Two classes of detection technology are being deployed to meet this threat. The first are explosives trace portals (ETP). The first generation of these trace portals has been deployed in some US airports and other security venues. These systems all use older IMS trace detection technology. Syagen’s MS ETP system is currently undergoing US Govt testing and offers greatly enhanced performance over the older IMS based portals. The second class is whole body imaging (WBI) which relies on either millimeter wave or x-ray backscatter radiation to give an anatomically revealing image of objects hidden underneath a person’s clothing. At the same time, WBI also provides a clear view of the human anatomy beneath the clothing. Each type of technology has its benefits and the most effective deterrent may inevitably be an integrated solution using both technologies.
The table below summarizes the important properties of the different methods used for screening people for concealed explosives.
Comparison of Different Personnel Screening Methods
