Peering inside an atom just got cheaper and greener


Some of the innards of the SwissFEL accelerator, which was cheaper to build and more compact than most similar facilities. Credit: Switzerland Global Enterprise

Optics and photonics

11 November 2020

A Swiss design could help to bring an ultra-high-resolution mapping tool to the scientific masses.

Researchers have slashed the cost and energy needed to produce high-energy X-ray pulses that are key to a powerful method of imaging atoms and molecules.

X-ray free-electron lasers (FELs) produce highly focused light pulses that are similar to a laser’s but have shorter wavelengths. They do so by accelerating electrons and sending them through arrays of permanent magnets with alternating poles, forcing the electrons to emit radiation in a tight beam. Researchers can use FELs to make ‘movies’ of molecular motion and to decode the structure of atoms and molecules.

Eduard Prat and his collaborators designed and fine-tuned the SwissFEL facility in Villigen, Switzerland, to produce high-energy photons — with a wavelength of one Ångstrom, or one hundred millionth of a centimetre — using lower-energy electrons than at comparable facilities around the world. This kept their machine relatively compact while enabling it to work with just 1.7 megawatts of electricity.

The SwissFEL technology could lead to further cost reductions, which could enable facilities to open around the world and expand researchers’ access to these facilities, the authors write.