Compact Synchrotron X-ray Device Could Democratize X-ray Research

Researchers have developed a new way to generate synchrotron X-rays they say will benefit everything from cancer detection to national security.

Ten-thousand times brighter than a hospital X-ray source, synchrotron X-rays are used in advanced medical imaging, among other things. They work by accelerating electrons to extremely high energies and then forcing them to shift directions periodically, causing the electrons to emit energy at X-ray wavelength.

The images synchrotron X-rays produce are clearer and they put off less radiation than their counterparts. However, massive and costly, they are only available a few sites worldwide. In the European Synchrotron Radiation Facility in Grenoble, France, for example, the electrons circle near the speed of light in a storage ring of 844 meters in circumference, with magnets changing the direction of the electrons.

Hoping to do to synchrotron X-rays what personal computers did to computing power, researchers from the University of Nebraska-Lincoln replaced the electron accelerator and the magnets with lasers, which they focused onto a gas jet in order to create a beam of relativistic electrons. They then focused another laser beam onto the accelerated electron beam, causing the electrons to vibrate and create a bright burst of synchrotron X-rays.

Though less than a dime in size, the accelerator and synchrotron increased the light's photon energy by a million-fold.

And while previous X-rays made using compact lasers "lacked several of the distinguishing characteristics of synchrotron," according to project lead and physics professor Donald Umstadter, the one he and his team created is the whole package, offering a much larger range of photon energies.

The key was finding a way to collide the scattering laser beam and laser-accelerated electron beam, both of which are micro-thin.

"Our aim and timing needed to be as good as that of two sharpshooters attempting to collide their bullets in midair," Umstadter said. "Colliding our 'bullets' might have even been harder, since they travel at nearly the speed of light."

The resulting invention could be used by Homeland Security in detecting concealed nuclear materials, doctors detecting cancerous tumors even earlier and scientists observing reactions too fast for conventional X-rays.