World's First X-Ray Laser Goes Live

smolloy writes "The world's first X-ray laser (LCLS) has seen first light. A Free Electron Laser (FEL) is based on the light that is emitted by accelerated electrons when they are forced to move in a curved path. The beam then interacts with this emitted light in order to excite coherent emission (much like in a regular laser); thus producing a very short, extremely bright, bunch of coherent X-ray photons. The engineering expertise that went into this machine is phenomenal — 'This is the most difficult light source that has ever been turned on,' said LCLS Construction Project Director John Galayda. 'It's on the boundary between the impossible and possible, and within two hours of start-up these guys had it right on.' — and the benefits to the applied sciences from research using this light can be expected to be enormous: 'For some disciplines, this tool will be as important to the future as the microscope has been to the past,' said SLAC Director Persis Drell."

Comments

Awesome

[MozeeToby]

I had the pleasure of taking a tour of the Advanced Photon Source at Argonne National Labs. They have a similar setup; using accelerated electrons to produce x-rays, the real achievement here is the coherency part. I wonder how this effects high speed x-ray crystallography, is it easier to decode the scatter if the light is coherent? Will we be getting real time videos of enzymes in action? If so I can only imagine what that will do for chemical and pharmaceutical research.

Re:Awesome

[thechao]

IAAECXRPX (I am an ex-computational-x-ray-protein-crystallographer). Lasers a bit left wing, since we usually use anode sources for x-rays on the home source and synchotrons for MAD sets. However, if the laser has tight enough phases (60-degrees) and coherency this is not just big but HUGE. Currently, there are two difficult steps in PX: (1) crystallization; and (2) phasing. The first is becoming easier using automated screening and robots (although we are only at the beginning of this process, so probably still 5--10 years out). The second has been considered one of the outstanding problems in (at least) biology if not all of science. To put this in perspective, it was only a few years ago that just *finding* the structure (phasing) was enough to warrant a Nature or Science paper. Nowadays you're gonna need some function, too, but the phasing is still spectacularly hard. If these guys have really done this, and they're getting good power, this will be a watershed event for all of biology.

Re:Awesome

[Bowling Moses]

Well for high-speed crystallography it isn't so much that data collection is the problem (for most applications). You can collect a high-quality data set of a protein at APS in under a half an hour. The real bottlenecks in x-ray crystallography is, was, and unfortunately most likely always will be protein crystallization. Way back in the day when protein crystallography was just starting, it was thought to be somewhat bizarre for proteins to crystallize. Fast forward four or five decades and now if your protein is reasonably soluble, reasonable stable, and has a definite structure (not all proteins have a well-defined structure and just flop about in a range of states), then you can probably get it to crystallize well enough to solve the structure. But it might take a long time to pull off, years even. But that's only for soluble proteins. If a protein is normally in the cell membrane, it is much, much harder. A cell membrane is basically soap. Soap doesn't crystallize. There are only a few structures of integral membrane proteins despite a lot of work on the problem. Also proteins that only have one domain or even just a helix poking into the membrane can be tricky--they're usually done by just removing the offending membrane bit but often suffer from solubility problems.

For part two, lasers produce monochromatic light. One technique for doing real-time x-ray crystallography involves using polychromatic x-rays. Normally you get a single, specific, monochromatic wavelength (, or at least close enough that for data processing you largely ignore everything else. The resulting diffraction pattern looks something like that seen on wikipedia's page. That page and links are actually pretty good. However you can use a broader spectrum of x-rays and get a different diffraction pattern due to having different wavelengths of light hitting your protein crystal over the course of the exposure, or a Laue diffraction image (ignore the color--computer added). Interpreting Laue diffraction's significantly harder because you also have to take into account that you have basically multiple different wavelengths of light producing multiple different, overlapping diffraction patterns. Unlike monochromatic diffraction patterns, which require exposure times of at least tenths of a second even at APS (or potentially hours on a weaker rotating anode x-ray source like at an individual lab), Laue diffraction can be measured in picoseconds--on the time scale of chemical reactions catalyzed by enzymes. A few groups have done time-resolved x-ray crystallography with reactions by building up series of Laue images. You can't do it for everything, though. Data processing problems aside you typically need a chemical reaction that can be triggered by light. Also, proteins frequently undergo structural reorientations during catalysis--the change will have to be small enough so that the packing of proteins in the crystal lattice will not be affected. Time-resolved x-ray crystallography using Laue diffraction is never going to be widely used, but the results can still be very exciting.

What these guys have in mind and how practical it is I don't know since I've somewhat shifted away from protein x-ray crystallography. I do remember going to a conference a few years ago where some guys wanted to use a single molecule to collect data on--by blasting the bajesus (that's a technical term) out of it with an extremely short, extremely massive burst of x-rays. They had the problem though of ripping off basically all of the electrons in the process, IIRC. Even at weak home rotating anode x-ray sources you still have to worry about radiation damaging your crystal (and affecting your resulting model of the protein), but blasting away all the electrons? That's like comparing a flyswatter and a tactical nuke.

A big medical breakthrough.

[Goalie_Ca]

Right now X-Ray sources are quite random and waste _a lot_ of energy. A nice pencil thin directional beam would do wonders for CT scanners.

Re:A big medical breakthrough.

[Sentry21]

As far as medical radiology goes, a pencil-thin beam would be nice for added precision, but also for dramatically reducing the radiation dose. My local hospital has stopped giving me CT scans because I've had so many in the past (out of necessity) that they don't want to fry me any more than necessary.

Replacing the emitters in a CT scanner, which basically spray you with radiation and rely on carefully-placed sensors to create the line-of-sight they want, with a directed, low-power beam that only hits with radiation those cells that actually need it, will dramatically reduce the amount of radiation that patients receive.

Re:A big medical breakthrough.

[Roger W Moore]

Actually, IIRC, you need a beam wide enough to irradiate the entire patient's body at once otherwise the Fourier transform used to generate the picture gives artifacts so I don't think a pencil thin beam will help. However I have heard that it is great for killing tumours. Apparently you can slice and dice them with a coherent X-Ray source and it is far worse for them than healthy tissue. This way you can reduce the collateral damage to tissue near the tumour.

World's *First* X-Ray Laser? I don't think so.

[imperious_rex]

The first x-ray laser was part of SDI research in the early 80's. Click here and here for more info.

Re:World's *First* X-Ray Laser? I don't think so.

[McNihil]

It actually says Hard X-ray's

http://hesperia.gsfc.nasa.gov/sftheory/xray.htm

This announcement believe it or not has actually made my day. It will 100% spur innovation like the original Red Lasers did.

Re:First?

[Martin Blank]

To be fair, the Nike-Hercules missiles were among the last nuclear defenses intended to be employed. The first was to knock out air bases with nuclear strikes to prevent bombers from getting in the air in the first place. After that came air interception using missiles such as the AIR-2 Genie. Nuclear-tipped SAMs would attempt to intercept over the ocean or unpopulated territory where possible (the Nike-Hercules had a range of over 75 miles), and explode over populated territories only if nothing else worked.

Re:Bah, that's nothing...- MALWARE!

[xonar]

Watch out, dont visit the above! It's a trap!

Re:The one question we all want to know.

[joe_frisch]

Its probably the WORST weapon ever built. A kilometer and a half long. Can only change its aiming point by a fraction of a degree. It took about 15 minutes to burn a pin sized hole in a piece of metal foil, and it only goes a couple of meters through air. Now if the bad guys decide to attack us with very slow moving, really tiny robots, one at a time, maybe we can do something.

DO NOT CLICK THAT LINK!!! - Malware!

[emmons]

It will fsck you up. Unless you're running linux - then it's just really annoying.

No, SDI did not collapse the Soviet Union

[amck]

There are problems with this idea.
(1) Its justification after the fact. No credible proof has been provided that this was ever the plan: rather, the Soviet Union collapsed economically,
in a way unexpected by the CIA and the intelligence community, then the SDI folks say "See ? that was our Sekrit plan all along". If it was the
plan, it shouldn't have been a suprise.
(2) SDI didn't change soviet spending. They did practically no SDI work (in comparison to the US), and Soviet military spending didn't change.
Counter-measures to SDI are / were far cheaper than SDI itself: SDI meant spending billions on new tracking and laser developments to appear
credible (even if no-one involved believed it would work); countering it meant a few dummy balloons and chaff. It risked bankrupting the US
far before bankrupting the SU.
(3) Not only did Soviet spending not change, the CIA knew that it didn't change, and yet SDI continued. A very expensive, failed, policy was continued
in order to keep money flowing into certain companies. It was a pork barrel.

The soviet economic collapse was triggered by OPEC, not SDI. When Saudi Arabia et al opened stopcocks and flooded the world with cheap oil,
the Soviet export economy collapsed.