Beamlines at the SACLA x-ray free electron laser

An X-ray free-electron laser facility in Harima, Japan, allowed scientists to create a nanoplasma from xenon atoms. Credit: RIKEN

Atomic and molecular physics

Weird form of matter seen at the moment of creation

The glare of an infrared flash illuminates xenon atoms’ transformation.

An exotic version of matter called a nanoplasma has been caught in the act of forming for the first time.

When a pulse of high-energy X-rays strikes a cluster of a few thousand atoms, it strips and scatters the atoms’ electrons, creating a gas of ions called a nanoplasma. The plasma is so short-lived that observing its birth has proved difficult.

Kiyoshi Ueda at Tohoku University in Japan and his colleagues delivered a powerful but brief pulse of X-rays to a nanometre-scale cluster of xenon atoms. This pulse was swiftly followed by a flash of near-infrared light, which enabled the researchers to observe the nanoplasma’s formation.

The X-ray pulse stripped the xenon atoms of some of their electrons to form a nanoplasma — a process that took less than 12 quadrillionths of a second, according to the team's observations. The pulse also created many highly excited atoms, which collided to form more ions within a few hundred quadrillionths of a second.