Yes We Scan: Have Post-9/11 Airport Screening Technologies Made Us Safer? [Slide Show]
Airport security breaches on and after 9/11 have led to the continual advancement of technologies such as millimeter wave imaging and backscatter scanners to prevent future tragedies
Credits: Transportation Security Administration
TERAHERTZ SCANNERS: Scanners that rely on terahertz rays—which lie between microwaves and infrared radiation on the electromagnetic spectrum—may be the future of passenger screening. They can penetrate common materials but do not seem to harm living tissue, and can identify compounds, such as hair gel or explosives. Such technology is now being tested at airports worldwide.
BAGGAGE X-RAYS: A midair explosion by a suicide bomber that killed all 34 people on board a National Airlines plane in 1960 sparked demands in the U.S. for baggage inspection devices. These x-ray machines have advanced by now to work like medical CT scanners, with sophisticated image-processing software to automatically screen checked baggage for explosives.
BACKSCATTER X-RAYS: Backscatter scanners beam low-level x-rays over a person's body, producing an image that resembles a chalk etching. The
TSA is planning to test new software for backscatter scanners that eliminates passenger-specific images, instead displaying the location of potential threat items on a generic outline of a person. Rapiscan Systems
MILLIMETER-WAVE SCANNERS: Millimeter-wave technology bounces millimeter-wavelength radio waves off the body to generate 3-D images. The TSA recently began installing new software on its millimeter-wave scanners to eliminate passenger-specific images. The software instead displays the location of potential threat items on a generic outline of a person.
PUFFER PORTALS: Explosive trace portals, often known as "puffers," blow gusts of air at those within to analyze particles shaken loose for any signs of explosives. These were first deployed to U.S. airports in 2004, with a peak of 94 portals in 37 airports. However, the Transportation Security Administration
(TSA) said frequent maintenance issues caused by the dirt and humidity common to most airports led it to begin phasing out puffers in 2008. Smiths Detection
BOMB-SNIFFING DOGS: Moments after a flight bound for Los Angeles took off from John F. Kennedy International Airport in New York City on March 9, 1972, the airline was notified that there was a bomb on board and the aircraft returned to JFK. A bomb-sniffing dog found the explosive 12 minutes before it was set to detonate. The Federal Aviation Administration created the Explosives Detection Canine Team Program thereafter so any aircraft receiving a bomb threat could quickly divert to an airport with a canine team. Bomb-sniffing dogs still play a key role in detecting explosives and deterring terrorists.
METAL DETECTORS: Metal-detecting scans of all airline passengers became mandatory in the U.S. at the start of 1973. Nearly all conventional airport metal detectors work by generating many magnetic pulses per second—a metal object passing through a metal detector influences how these pulses collapse.
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