What would you shoot if you had the most powerful X-ray laser in the world? Researchers at the SLAC National Accelerator Laboratory in California shot droplets of liquid, but the reason behind it is not at all frivolous. They filmed the microscopic event in order to improve future X-ray lasers – and set it to a bit of classical music in the video below.
“Understanding the dynamics of these explosions will allow us to avoid their unwanted effects on samples,” said Claudiu Stan, lead author of the paper, in a statement. “It could also help us find new ways of using explosions caused by X-rays to trigger changes in samples and study matter under extreme conditions. These studies could help us better understand a wide range of phenomena in X-ray science and other applications.”
The X-ray laser is used to study phenomena that are either too fast or too small to be studied in any other way. Liquids are an excellent way to bring samples to the path of the laser, so studying these explosions will allow scientists to make more precise measurements. The results were published in Nature Physics.
The observations, which focus on the first 9 millionths of a second, reveal an explosive vaporization followed by a strong interaction between the gas and the liquid. When individual droplets are shot, the shockwave propagates to nearby droplets that quickly boil away.
When the laser instead encounters liquid jets, it first forms a gap through it, which expands and forces the liquid into an umbrella-shaped film that then falls back on the jet. Understanding how this gap forms is fundamental for when the upgrade to the current laser, called LCLS-II, comes online.
“The jets in our study took up to several millionths of a second to recover from each explosion, so if X-ray pulses come in faster than that, we may not be able to make use of every single pulse for an experiment,” Stan added.
Thanks to the data collected in the experiments, the team was able to construct a mathematical model to describe what happens to the liquid when it interacts with the laser. This will allow scientists to tune our current and future lasers to accommodate for these explosive reactions and use this technology to its full potential.