Airport Security Screening Technologies
April 20, 2010 2 Comments
Written by: Vincent Szajdzicki
Following the failed attack on flight 253, a lot has been made of new screening technologies - Body Scanners, Explosive Trace Detection Portals, Dual View and 3D X-ray Machines - being implemented into airport security checks.
This article’s aim is to identify the types of security screening technology passengers are likely to encounter in the near future and determine how effective they can be in stopping future terrorist attacks.
Body Scanner Technology
The proposed introduction of Full Body scanners into Airport security installations has garnered by far the most publicity with human rights activists decrying the dangers these scanners pose on both the health and privacy of individuals.
Millimeter wave scanners cost around $100,000 and are therefore cheaper then backscatter x-ray and transmission x-ray technology. Body-Scanners using Millimeter waves provide the least health concerns as they use naturally occurring radiation in the earth’s atmosphere and do not subject others to additional ionising radiation exposure. They are also quick and therefore would have negligible effect on passenger throughput if implemented. The images produced by Millimeter wave machines are also far less graphic then for other types of scanning technology and therefore offer far more privacy to those being screened.
Full -Body Scanners like the L3 ProVision also offer the option to blur certain parts of the body; however this would completely defeat the purpose of their introduction. To completely negate any privacy concerns, L3 have also developed the ProVision AT which converts the scanned image into a generic stick figure and then affixes any concealed items onto it.
Millimetre wave technology can also be used in standoff scanners, as demonstrated by Brijot Imaging Systems’ GEN2. One of these millimetre scanners can scan 360 people per hour and detects concealed items on people from a distance without them having to stop.
While millimetre technology is quicker, cheaper and offers less privacy issues then other technologies, the quality of image leaves a lot to be desired. After all new technology must have the capabilities to detect new and existing threats and there are serious doubts as to whether millimetre wave scanners could have identified the IED concealed in Abdulmutallab’s underpants.
Backscatter X-ray technology costs around $150,000 and uses low doses of x-ray radiation to scan the body. Machines like the Rapiscan Secure 1000 and AS&E’s SmartCheck rotates the individual slowly subjecting them to ultra low doses of x-ray radiation and delivers a better quality of image then Millimeter wave Technology.
The better image quality does however make for slow throughput and more worries over privacy. To combat this AS&E have developed the SmartCheck HT which can provide front and back scans of the individual without any rotation involved. They have also developed a privacy setting which only shows the outline image of the individual and any concealed items within it. As with Millimeter Technology, these machines are not able to store any x-ray images.
In terms of Health issues, AS&E use Z Backscatter which they claim only subjects individuals to the same amount of radiation as they would get from flying in aircraft for 2 minutes at 30,000 feet (9,200metres). That is the equivalent of 0.1 millisieverts, which considering the International Commission on Radiological Protection recommends that radiation should not exceed 1 millisievert a year is a small price to pay for better security.
Backscatter technology does offer advantages to other technologies in that it provides a relatively good quality image, however using them on every passenger would severely lengthen queues, something that could prove attractive to a suicide bomber.
Transmission X-ray technology would be seen as controversial, but is worth considering in some rare circumstances. It is similar to a medical x-ray and offers through body scanning allowing for the detection of items concealed internally.
As security measures only detect items beneath clothes, the next logical step for terrorists would be to conceal their IEDs internally just as traffickers currently do with drugs. In fact, the attempted assassination on a Saudi Prince in 2009 is thought to have been carried out using an anally concealed IED.
ODSecurity’s SOTER RS and Adani’s Conpass systems are used by Customs in many countries around the world for clearing purposes as it provides them with the technology to identify internal carries but its use in airports is still very limited.
So while this technology would be seen as controversial, it is important to note that the only other way of detecting internally concealed items currently is quite unpleasant. The fact is Transmission X-ray should only be used on someone who is seen as high risk following profiling and other security checks.
Explosive Trace Detection Portals
Explosive Trace Detection Portals were for a long time seen as the next major implementation into security checkpoints but have been recently usurped by the full body scanners. This technology uses air showers to collect minute particles from clothing and the human body and analyses them against their database of explosives.
The advantage of these portals is that they do not invade personal privacy, and are completely automated therefore negating screener error. However their ability to only detect explosives present in their database makes them vulnerable if terrorists develop the capability to manufacture new types of explosives.
The company TeraView have developed automated body scanners that use terahertz light to detect explosives on individuals. Terahertz light lies between radio and light waves on the electromagnetic spectrum and does not produce any ionising radiation. As explosive material absorbs this type of light strongly at certain frequencies it means machines using this technology should be able to distinguish between explosives and other materials.
Luggage Screening Technology
Apart from a few image enhancements buttons and slightly better resolution, X-Ray has not really evolved much in the last 20 years when compared to other types of technology.
Multi View and 3D X-Ray Machines
Multi view X-ray machines use existing x-ray technology but offer multiple (2-5) of luggage to screeners providing them with a complete perspective regardless of their orientation inside the system.
The screener will be asked to concentrate on one screen at a time and if required will look at the others eliminating the need for rescreening bags at different angles. Machines that use this technology like the Rapiscan 620DV and Smiths Detection HI-SCAN 6040aTIX also include automated detection software designed to identify the presence and position of a threat based upon context, material density, size and effective atomic number.
3D X-Ray machines have imaging software that offers both 2D and 3D views of bags that can be rotated. This should theoretically help the screener identify items in the bag and make threat concealment behind other items harder for terrorists. However given the short amount of time available to screeners to view each bag (6seconds) it is unclear as to whether they will have the time to use this new gadget effectively.
All these technologies have their pros and cons and none should be seen as the definitive answer to securing airports and other high security establishments from terrorist attacks. Time constraints and budget restrictions make it impossible to use all of these technologies on every passenger. Security personnel must therefore be trained to distinguish between high and low risk passengers enabling them to use the required level of screening on each individual (see profiling article).
The automation of threat detection, while helpful in many ways, can lead to the job of security screener being devalued. We should not take it for granted that automated systems will detect each and every threat presented to them. We should be training staff regularly and providing them with the skills, knowledge and understanding that will enable them to detect threats.
Technological advances in security screening are to be encouraged but we should always remember that the human factor is just as important.