1.   Although the next generation of trace detectors focuses on walk-through systems that could check every passenger, the technologies vary.

2.   According to Fainberg, trace detectors are generally sensitive enough to detect nitroglycerin on the luggage of passengers who are taking it in medication for heart conditions.

3.   More properly called particle detectors or trace detectors, these devices are perhaps best known from their use in airports.

4.   The machines, known as trace detectors, can sense tiny particles of explosives and drugs.

5.   The San Francisco airport was the first in the nation to test the explosive trace detector, Wilson said.

6.   Then the paper is inserted into a hole in the explosive trace detector.

7.   Trace detectors are commonly used on laptop computers and other fairly large objects that could conceal a bomb that X-rays cannot detect.

8.   Two weeks ago, the company also unveiled its new SecurScan trace detector, which is used to test for traces of explosives on passengers and their carry-on bags.

9.   Some airports will have only trace detectors and some will have a combination of the two.

10.   The trade-off is that the trace detectors require far more trained security employees than the explosive detection machines, Mica said.