One of the world's best radon detectors just got smaller

The need for a smaller, more transportable version of ANSTO's 1,500-liter atmospheric radon-222 monitor, and with a calibration traceable to the International System of Units, prompted the team to develop a 200-liter radon ...

The way we define kilograms, meters and seconds changes today

We measure stuff all the time—how long, how heavy, how hot, and so on—because we need to for things such as trade, health and knowledge. But making sure our measurements compare apples with apples has been a challenge: ...

New X-ray measurement approach could improve CT scanners

A new measurement approach proposed by scientists at the National Institute of Standards and Technology (NIST) could lead to a better way to calibrate computed tomography (CT) scanners, potentially streamlining patient treatment ...

Detection of single photons via quantum entanglement

Almost 200 years ago, Bavarian physicist Joseph von Fraunhofer discovered dark lines in the sun's spectrum. It was later discovered that these spectral lines can be used to infer the chemical composition and temperature of ...

Graphene joins the race to redefine the ampere

A new joint innovation by the National Physical Laboratory (NPL) and the University of Cambridge could pave the way for redefining the ampere in terms of fundamental constants of physics. The world's first graphene single-electron ...

Explained: Femtoseconds and attoseconds

Back in the first half of the 20th century, when MIT's famed Harold "Doc" Edgerton was perfecting his system for capturing fast-moving events on film, the ability to observe changes unfolding at a scale of microseconds—millionths ...

Toward a global microwave standard

Much of what is known about decadal climate change – and much of what appears on the evening weather forecast as well – comes from satellite-based remote sensing of microwave radiation at different levels in the ...

page 1 from 2