Building the World's Brightest X-Ray Laser (cnet.com) 15
Thirty feet underground and a stone's throw from Stanford University, scientists are putting the finishing touches on a laser that could fundamentally change the way they study the building blocks of the universe. CNET reports: When completed next year, the Linac Coherent Light Source II, or the LCLS-II , will be the second world-class X-ray laser at the Department of Energy's SLAC National Accelerator Laboratory. CNET was given the rare opportunity to film inside the more than 2-mile long tunnel ahead of the new laser's launch. The first LCLS, in operation since 2009, creates a beam capable of 120 light pulses per second. The LCLS-II will be capable of up to 1 million pulses per second, and a beam 10,000 times brighter than its predecessor.
You can think of the LCLS as being like a microscope with atomic resolution. At its core it is a particle accelerator, a device that speeds up charged particles and channels them into a beam. That beam is then run through a series of alternating magnets (a device called an undulator) to produce X-rays. Scientists can use those X-rays to create what they call molecular movies. These are snapshots of atoms and molecules in motion, captured within a few quadrillionths of a second, and strung together like a film. Scientists across nearly every scientific field have come from all over the world to run their experiments with the LCLS. Among other things, their molecular movies have shown chemical reactions as they happened, demonstrated the behavior of atoms inside stars, and produced live snapshots detailing the process of photosynthesis.
Though both lasers accelerate electrons to nearly the speed of light, they'll each do it differently. The LCLS's accelerator pushes the electrons down a copper pipe that operates at room temperature, designed to be activated only in short bursts. But the LCLS-II is designed to run continuously, which means it generates massive amounts of heat. A copper cavity would absorb too much of that heat. That's why engineers turned to a new superconducting accelerator, composed of dozens of 40-foot-long devices called cryomodules designed to run at two degrees above absolute zero (-456 degrees Fahrenheit). They're kept at operating temperature by a massive cryogenics plant above ground.
[T]he LCLS-II will allow SLAC scientists answer questions they've been trying to solve for years. "How does energy transfer happen inside molecular systems? How does charge transfer happen? Once we understand some of these principles, we can start to apply them to understand how we can do artificial photosynthesis, how can we build better solar cells." Scientists at SLAC hope to produce their first electron beam with the LCLS-II in January, followed by their first X-ray in the summer, which they'll refer to as their first "big light" event.
You can think of the LCLS as being like a microscope with atomic resolution. At its core it is a particle accelerator, a device that speeds up charged particles and channels them into a beam. That beam is then run through a series of alternating magnets (a device called an undulator) to produce X-rays. Scientists can use those X-rays to create what they call molecular movies. These are snapshots of atoms and molecules in motion, captured within a few quadrillionths of a second, and strung together like a film. Scientists across nearly every scientific field have come from all over the world to run their experiments with the LCLS. Among other things, their molecular movies have shown chemical reactions as they happened, demonstrated the behavior of atoms inside stars, and produced live snapshots detailing the process of photosynthesis.
Though both lasers accelerate electrons to nearly the speed of light, they'll each do it differently. The LCLS's accelerator pushes the electrons down a copper pipe that operates at room temperature, designed to be activated only in short bursts. But the LCLS-II is designed to run continuously, which means it generates massive amounts of heat. A copper cavity would absorb too much of that heat. That's why engineers turned to a new superconducting accelerator, composed of dozens of 40-foot-long devices called cryomodules designed to run at two degrees above absolute zero (-456 degrees Fahrenheit). They're kept at operating temperature by a massive cryogenics plant above ground.
[T]he LCLS-II will allow SLAC scientists answer questions they've been trying to solve for years. "How does energy transfer happen inside molecular systems? How does charge transfer happen? Once we understand some of these principles, we can start to apply them to understand how we can do artificial photosynthesis, how can we build better solar cells." Scientists at SLAC hope to produce their first electron beam with the LCLS-II in January, followed by their first X-ray in the summer, which they'll refer to as their first "big light" event.
That's pretty cool and all (Score:4, Funny)
But where are they gonna find a shark that's big enough?
Re: X-ray optics (Score:5, Interesting)
With x-rays this energetic, there are no optics since the rays just go right through anything. But, since the generated x-rays are coherent and are formed in a very narrow beam, you can study the diffraction patterns created after the x-rays pass through the sample.
Here's a great talk about how these light sources work and some of the history and physics: https://youtube.com/watch?v=RK... [youtube.com]
Brightness (Score:2)
Reading the summary Referrng to brightness I kept thinking " you keep using that word but I don't think it means what you think".
Brightness doesn't mean more power it means more concentrated power. It has to do with how much e energy you can deliver to a slam area in a short time. This is why a 1 watt laser can be brighter than a 1000 watt light bulb.
So it's unclear to me if they mean the laser was more powerful or if it can be focused tighter or if it's total energy per pulse or shorter pulses with the s
Re: (Score:3)
The remarkably good conference presentation video linked by As_I_Please above, introduces a combined figure of merit: Brilliance. Answer "all of the above". Skip ahead to 9:00 for quick confirmation, then view the rest as time allows. The biochemistry simulations from Harvard that are in the introductory material, are inspiring.
I was fortunate to be on academic tours of SLAC while LCLS was being constructed, and of LBL ACLS when the beam was off, allowing the experience of walking around on top of a sync
Re: (Score:2)
Re: (Score:2)
With x-rays this energetic, there are no optics since the rays just go right through anything.
Pinhole lenses made from an absorbing material can be used for X-ray and gamma-ray imaging, which also leaves the possibility of diffraction optics, but I know pinhole lenses have been used.
How bright? (Score:3)
So bright it will literally melt your face right off!
Re: How bright? (Score:2)
Is it cruel and unusual punishment if it's for science?
Re: (Score:2)
So bright it will literally melt your face right off!
Do not look into beam with remaining face.
Really? (Score:2)
Rays that one cannot see can be 'bright'?
Re: (Score:3)
Why not? Brightness is the intensity of light. X-rays are light. You will also find terms like 'glow' and 'shine' and 'dim' used for light outside the visible spectrum.
"Come to run experiments" (Score:2)
Yeah, right.
It's a freaking 2 mile long laser. They all came to have fun with it.
Since it is an X-ray laser... (Score:2)