If you’ve flown in the U.S. in recent years, you’re probably familiar with the airport security experience of entering a booth, raising your hands above your head, and having a machine check your body. That machine is called a millimeter wave scanner.

I’ve done this many times and never given it much thought. But National Institute of Standards and Technology (NIST) researcher Jack Glover sure has. He’s a physics expert who works to make sure the Transportation Security Administration (TSA) can test those machines effectively.

This work has saved the government hundreds of millions of dollars and, more important, kept millions of passengers and flight crew members safe in the air.

So how do you keep those machines working properly? As with most things at NIST, it all comes back to measurement and standards.

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