The best digital cameras on the market open their shutter for about four-thousandths of a second to take a photo. You’ll need a shutter that clicks more quickly to capture the atomic activity. In 2023, scientists unveiled a way to achieve detection speeds of a trillionth of a second, or 250 million times faster than those digital cameras. This makes it capable of capturing something very important in materials science: dynamical turbulence.
This occurs when groups of atoms move and dance in a substance in specific ways over a period of time, for example due to vibration or temperature changes. It is not yet a completely understood phenomenon, but it is important for the properties of materials and their interactions. The ultrafast observational speed system gives us much more insight into what happens with dynamical perturbation, and the researchers refer to their invention as the variable atomic pair distribution function, abbreviated vsPDF.
Only with the new vsPDF tool can we see this side of materials, said materials scientist Simon Billing of Columbia University in New York. With this technology we will be able to watch matter and see which atoms are dancing and which are sitting out.
Faster detection speed means more precise timing, which is useful for rapidly moving objects such as quivering atoms. Use a low observer speed in a sports photo, for example, and you will end up with blurry players in the frame.
vsPDF uses neutrons to measure the position of atoms to achieve stunningly fast capture, rather than traditional imaging techniques. The way neutrons hit matter and pass through it can be traced to measure surrounding atoms, with changes in energy levels equivalent to adjustments to the observational speed.
These differences in camera speed, in addition to the camera’s trillionth of a second speed, are significant: they are vital in picking out dynamic disturbance from the related but different static disturbance, the natural background vibrating in situ of atoms that does not enhance the function of matter.
It gives us a whole new way to unravel the complexities of what happens in complex materials, and the hidden effects that may increase their properties, Billing said. The researchers trained the neutron camera on a material called germanium telluride (GeTe), which, because of its special properties, is widely used to convert waste heat into electricity, or electricity into cooling.
Scientific understanding of these materials and processes can be improved through models based on observations captured by the new camera. There is still a lot of work to be done to make vsPDF ready to be a widely used testing method. We expect the vsPDF technique described here to become a standard tool for reconciling local and intermediate structures in energy materials,” the researchers explain in their paper.