The European X-ray Free-Electron Laser recently came on-line as the biggest and brightest source of X-rays on planet Earth. Those brilliant X-ray beams will allow chemists to do groundbreaking research on enzymes, solar-cell materials, and more.

But with great science comes great responsibility. In our latest Stereo Chemistry podcast, C&EN contributing editor Mark Peplow visits the X-ray facility to learn about its growing pains, its staff’s unique approach to keeping beamlines running, and some of the facility’s early successes. Listen to the full episode at

The following is a transcript of this podcast.

Matt Davenport: It’s one of the most fundamental questions a chemist can ask: how are the atoms arranged inside… stuff? The answer not only tells you about the chemical structure of a material–it can reveal why it has certain electrical or magnetic properties, for example. Or why it’s so good at getting involved in a particular reaction. And one of the best ways to figure out that structure relies on X-rays.

In this episode of Stereo Chemistry, we’re going to take you inside the biggest and brightest source of X-rays on planet Earth – an X-ray free electron laser — and we’ll hear about the amazing science that people are doing with it. But first, a little history.

So just over a century ago, physicists realized that when they fired X-ray light through a crystal, those X-rays would scatter off the crystal’s atoms to form a unique pattern. Not to William Lawrence Bragg, but the physicists had also set up a film to record that scattered light. What developed for each crystal was a unique pattern of bright spots and dark regions. That pattern is a fingerprint that tells scientists precisely how the atoms are arranged.

Fast forward to the 1970s, researchers got their hands on a new and more powerful source of X-rays called synchrotrons. These particle accelerators make electrons go so fast that they spit out bursts of X-rays. And these bursts have been used to determine the structures of tens of thousands of different proteins, for example. But synchrotron X-ray bursts are still not bright enough to get structures from nano-sized crystals, or things that simply refuse to crystallize at all.

That’s where X-ray free electron lasers come in. And just some record-keeping up front: X-ray free electron laser is abbreviated X-F-E-L or “X-fell.” And that’s not to be confused with the short-lived XFL American football league, which, for some reason, is apparently coming back in 2020. But that’s for another episode.

At any rate, XFELs work on a similar principle to synchrotrons, but they make pulses of X-rays that are a billion times brighter, so you can get chemical structures that you just wouldn’t be able to see using any other X-ray sources. Over the past decade, several billion-dollar XFEL facilities have been built around the world.

The newest one is called the European X-ray Free Electron Laser, and it can produce the brightest X-ray pulses yet. Researchers started bringing their samples there in September of last year, but it’s had its fair share of teething problems. So we sent C&EN contributing editor Mark Peplow there last month to find out how its all going. Welcome to Stereo Chemistry, Mark.


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