Discovery paves way for 3D X-rays

Lincoln, Nebraska – The groundwork has been laid for three-dimensional, real-time X-ray images of patients by scientists at the University of Nebraska-Lincoln (UNL) and two Russian institutes.

In a paper to be published in Physical Review Letters, the delightfully named UNL Physics and Astronomy Professor Anthony Starace and his colleagues give scientists important clues into how to unleash coherent, high-powered X-rays.

“This could be a contributor to a number of innovations,” Starace said.

X-ray radiation can be created by focusing an optical laser into atoms of gaseous elements – usually low-electron types such as hydrogen, helium, or neon. Through high-harmonic generation (HHG), the laser light interacts with those atoms’ electrons, causing them to vibrate rapidly and emit X-rays.

Unfortunately, the X-ray light is very weak. Scientists have attempted to improve it by using higher-powered lasers, but success has been limited. “The problem is, the intensity of the radiation [the atoms] produce drops very quickly,” Starace said.

Starace’s group applied HHG theory to heavier gaseous atoms having many electrons – elements such as xenon, argon and krypton. They discovered that the process would unleash high-energy X-rays with relatively high intensity by using longer wavelength lasers that happen to drive collective electron oscillations of the many-electron atoms.

“If you use these rare gases and shine a laser in on them, they’ll emit X-rays with an intensity that is much, much stronger,” Starace said. “The atomic structure matters.”

Starace said that the findings could lead to more powerful and precise X-ray machines that could generate a 3D hologram of his or her heart, beating in real time. Nanoscientists could also benefit, Starace said, as the high-intensity X-rays could be used to make 3D images of microscopic structures.