Detection Devices

Backscatters

Use low-intensity X-ray beams to see through clothing

Per-unit cost:$139,000 to $142,000, including installation

Total investment: TSA owns one device that cost $142,000

Advantages: Can spot plastic and liquid explosives under clothing

Problems: Privacy rights of passengers, bulky, expensive installation, slow

Millimeter wave machines

Bounce radio frequency energy off passengers and analyze the reflection

Per-unit cost:$187,000 including installation

Total investment: TSA purchased eight devices for $1.7 million

Advantages: Can see through clothing and scan passengers quicker than backscatter devices

Problems: Privacy concerns, images not as clear as backscatter

Explosive trace portals

"Puffers" blast air on passengers and analyze particles that float off their skin or clothes

Per-unit cost:$97,000 to $140,000

Total investment:$28 million

Advantages: Can detect traces of explosives on clothing

Problems: Slow, unreliable, expensive to maintain

Explosive detection systems

MRI-like machines that screen checked bags

Per-unit cost:$285,000 to $1.2 million

Total investment: More than $5 billion to purchase, maintain and install 1,782 devices

Advantages: Efficient and one of the most sophisticated technologies for checking for explosive material

Disadvantages: Requires a lot of manpower to scan and sometimes open bags