More on the LCLS

One story is on SLAC Today about a labor pool group that does a lot of the miscellaneous tasks around the grounds. It's nice to interview regular guys who don't get a lot of props for their hard work and to recognize that without their efforts, jobs on-site would be much more tedious and frustrating.

On to today's main topic; the Linac Coherent Light Source. Some of you may remember me talking about it in a previous blog. I described how the LCLS works, how it takes x-rays produced from accelerated electrons to take pictures of extremely small objects extremely quickly.

Revisit that post here, or visit the LCLS website here, for a refresher…

Today's question is this: How do the scientists actually prepare a sample of something to put in front of this amazing x-ray laser beam?

Answer: Good question.

There are currently two projects underway at SLAC to answer this question. One is called the LCLS Ultrafast Science Instruments (LUSI) project and the second is known as Photon Ultrafast Laser Science and Engineering (PULSE). The purpose of LUSI is to investigate hardware technologies to be used with the LCLS and PULSE was commissioned to explore how the LCLS can be used to its full potential.

For example, technologies exist that can drop a stream of single molecules into the beam line to "take its picture." But every time it drops a molecule, it is oriented in a different way. This makes it extremely difficult to create a high-resolution image of the complex 3-dimensional structure that is a molecule.

Current projects using x-rays to probe molecules have to crystallize the sample first. This makes the sample uniform and simplifies the calculations immensely. However, some molecules, proteins, or other objects can not be crystallized, and the LCLS is capable of so much more than investigating crystallized structures. So one of the projects is to create a machine that can inject a single molecule into the beam line in roughly the same orientation every time.

So the question of how exactly samples and materials are going to be probed by the LCLS beam remains unanswered. But be assured that many scientists are working on it, and when the time comes, the LCLS will produce an amazing array of results.

This is but one of the many projects currently underway at SLAC to ensure that when the LCLS comes online in a couple of years, we will be ready to use it to its full potential.