The Linac Coherent Light Source

*****WARNING*******WARNING*******WARNING

(Insert flashing red lights and buzzing alarm sounds)

The post you are about to read is very, very scientific, though I shall do my best to make it readable. This would be much easier if I understood the subject matter--the LCLS--myself. But a good friend who has a Chemical Engineering background has requested more light be shed on the visualization of chemical reactions as they occur mentioned a few days ago. So take a deep breath my friends, cry havoc! and let slip the dogs of war....

Let's start with the Stanford Synchrotron Radiation Laboratory (SSRL). It turns out that when electrons, having been accelerated to nearly the speed of light, are forced to change directions they emit a certain type of x-ray called, you guessed it, synchrotron radiation. Magnets installed in the ring that keeps the electrons flowing in a circle, called "wigglers," force the electrons to change directions, causing them to emit this radiation. The radiation is then harnessed and shot down a beam line. Scientists place samples in front of the x-rays. Some of the x-rays will pass right through the sample, but some will bounce of atoms, protons, molecules, and the like causing a diffraction pattern which is detected and analyzed into a picture by a computer.

If this confuses you, you're not alone. The computer spits out a pattern that looks like a bulls-eye target which people who are smarter than me can somehow read.

Technology... go figure.

Now the SSRL is good, but we can do better. Because of the longish wavelengths of the x-rays, there is a limit to how small of objects this technique can work with. Also, the x-rays pretty much always (someone correct me if I'm wrong) destroy the sample before many pictures can be taken.

Enter the LCLS.

The new technology takes the same radiation made by the same electrons but focuses them into a *Dr. Evil quote marks* "laser beam." The x-rays' wavelengths are synchronized together in amazingly short bursts of amazingly bright light.

Pauses....
Crowd responds--"How fast is it? How bright is it?"

I thought you'd never ask.

Brighter than 100 million light bulbs and faster than it takes light to travel the thickness of a sheet of paper. That's femtoseconds baby, a quadrillienth of one tick of the clock. Light reaches the moon from Earth in 1.3 seconds.

Think about that for a second...

Let that settle in...

Wow.

OK, moving on...

One problem with x-ray imagery is that it often destroys the test material. The LCLS is so fast, it can take enough pictures to make a flip-book of a molecule disintegrating before our very eyes before it has time to be obliterated.

And because it is so fast, it can take pictures of chemical reactions as they are occurring. Right now we have pictures of the before and after, but for the first time we will be able to peer into the actual process.

Imagine the possibilities.

Well, if you followed that at all, your mind is now totally blown. And if I completely lost you, your mind is totally blown.

Either way, for more mind-numbing numbers, and more detailed information that is probably clearer than this post I'm making at 11:00 pm, check out this brochure. It's old, but good. (I'm on the committee to make a new one.) Also, the website for the LCLS is here, and an article from Symmetry is here.

Good night, and good luck...