How the LCLS-II laser helps scientists unlock origins of the universe

Speaker 1: I'm about 30 feet underground right now at the slack national accelerator laboratory in Northern California. Now down here in these tunnels, they're building one of the world's most powerful lasers. The LC LS two Speaker 1: [00:00:30] Every day, thousands of people drive highway two 80 between San Francisco and Silicon valley. But few realize they're driving directly over one of the most advanced pieces of technology on the planet. It's a device that pushes particles to nearly the speed of light and helps scientists unlock the origins of our universe. Before we go any further, let's get some acronyms outta the way. The LCS or line a coherent light source is a more than [00:01:00] two mile long particle a device that speeds up charge particles and channels them into a beam. Think of it like a microscope with atomic resolution, allowing scientists to observe atoms and molecules in details, never thought possible. LCS is one of the most powerful devices of its kind in the world. Allowing researchers watch chemical reactions as they happen. Observe the behavior of atoms inside stars and produce live snapshots detailing [00:01:30] the process of photosynthesis. It's the backbone of slack, the Stanford linear accelerator center, a joint laboratory between the university and the us department of energy In operations. Since 1966, research at slack has netted four Nobel prizes. It's helped scientists understand the transmissions of diseases like Zika allowed them to study air pollution on a micro scale and helped [00:02:00] develop stronger and lighter materials for the aerospace industry. But what do lasers have to do with any of that stuff? They help scientists create what they call molecular movies. These are snapshots of atoms and molecules in motion shot within a few quadrillions of a second and strung together. Like a film Speaker 2: LCS is capable of making pulses all the way down below amp. A second. A femtosecond is to a second as a second is to the age of the universe. Speaker 1: At this time scale, [00:02:30] scientists can better understand how light and matter interact. This is Speaker 2: Where the very first things happen that electrons inside of molecules absorb energy from a light pulse, and then they transfer this energy into molecular vibration or into motion Speaker 1: Scientists like James cryon use these movies to capture groundbreaking experiments in chemistry, physics, human health. Just about any scientific field you can think of [00:03:00] Back in 2009, slack scientists fired up LCS for the first time. Its most powerful accelerator to date. LCS can produce up to 120 pulses or movie frames per second, creating the brightest x-rays on the planet. But this world class machine is about to get the mother of all upgrades For the last five years. Scientists at slack have [00:03:30] been building its next generation particle accelerator to work alongside L CS L C S two is a super conducting accelerator at when finished will be 10,000 times brighter than its predecessor. The laser will have the ability to produce up to 1 million pulses per second. Opening the door for experiments that are impossible Speaker 3: Today. You think about a strobe light that goes off 120 times. You see one image. If it goes off a million times in a second, you get a much different image. So you can create a much better [00:04:00] movie. Speaker 1: The LCS two upgrade stretches across about a third of the two plus mile stretch of the original LCS tunnel. It all starts here at the super conducting electronic accelerator or the gun as it's sometimes called. Speaker 3: This is the beginning of the electrons journey for LCS two. Okay. Speaker 1: The heart of the gun is that big cylinder its job is to use flashes of light to produce a stream of electrons or an electron beam. Those electrons get [00:04:30] supercharged by a powerful radio frequency field on their way to the gun's exit. That field is so powerful. It produces about the same amount of heat as 80 microwaves on full hour running continuously. That's what all those orange hoses are for. They pump water to keep the system cool. After exiting the gun, the electron beam travels through this string of 37 massive cryo modules, something you won't find on the original LCS. Speaker 3: The LCS one is a normal conducting machine. So it's built with copper, [00:05:00] accelerating struck the L seals two accelerators are designed to run continuously. So it's a super conducting machine. The cavities are made from ni OUM. So ni OUM is a material that when you cool it down to liquid helium temperature, it becomes super conducting. Speaker 1: The cryo modules are kept at a temperature of two degrees above absolute zero or minus 456 degrees Fahrenheit. And keeping them at that temperature is a massive operation in itself. [00:05:30] A team runs this cryo plant above ground that delivers super cooled helium to those cryo modules down below. This Speaker 4: Is where we keep our I in the gas form. So we have six storage of 110 cubic meter. Each. We have a total inventory for about four tons of P for the system. Speaker 1: Next stop for the beam is what's known as the switchyard. This is where the electrons from LCS and LCS two get redirected to different lines [00:06:00] depending on what type of experiment they're being used for Speaker 1: Earlier, we were up at the start of the line and we saw that super conducting electronic accelerator. Now we're about two miles away and what's known as ator hall. This is about a hundred meters of alternating magnets that convert that beam into x-rays the magnets space. Just a few millimeters apart are arranged in a pattern that pushes [00:06:30] the electrons into a wiggling motion. Yes, that is the technical term that undulating motion forces the electron to emit some of their energy in the form of x-rays which bunch together and reinforce each other, creating a boost in x-ray power that coherent light source. Speaker 5: Well, you can imagine an incandescent light bulb might be 60 Watts, but it's just radiating in any direction across a very wide spectrum of colors. Coherent radiation has very well defined direction almost as [00:07:00] if you know where you're able to harness all of that light and focus it into a very, very small spot. Speaker 1: And precision is everything takes an entire team working 24 7 to ensure the ator are perfectly tuned. Speaker 5: The entire beam goes through here with five micron precision. And so that's five microns out of the 130 meter length of this ator hall. And so, you know, better than a part per million in terms of precision and alignment, probably one of the straightest objects in the world, Speaker 1: [00:07:30] Like other parts of slack, ator hall gets an upgrade for LCS. Two it's original line of magnets is replaced by two separate lines. The line on the right generates hard x-rays. Those are x-rays with shorter wavelengths that can probe smaller structures, particularly useful in material and biological sciences. The line on the left generates soft x-rays with longer wavelengths, which scientists can use to study energy and chemical reactions. And now that [00:08:00] we've got our x-rays scientists further down the line can make those molecular movies. Speaker 2: I'm gonna jump up and down and be so excited. We're gonna enable experiments that I've been wanting to do for years and years. Speaker 1: Dr. Crayon works in what's known as near experimental hall. Our next stop on the line. This facility is broken up into four main areas known as Speaker 2: Hus. This one has some kind [00:08:30] of cool stuff in it. If we can duck in here real Speaker 1: Quick within these hus scientists can swap out different experiments related to everything from molecular and atomic physics to biology. And, and this is where the LCS two and it's 1 million pulses per second, become a game changer. It's such a Speaker 2: Higher rep rate that we all of a sudden take experiments that we say that's not feasible and say it's doable. And it's doable. In a matter of days, Speaker 1: This ability to observe processes on different timescales will open up new doors for scientific research, allowing scientists [00:09:00] to answer questions they've been trying to solve for years. Speaker 2: 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 can we do artificial photosynthesis? How can we better understand photo devices? How can we build better solar cells? I think that it's absolutely fair to say that ILC LS two will usher in a new era of science. Speaker 1: [00:09:30] All right. So this is it. We finally reached the last stop of this incredibly long x-ray laser. This is called F E H or far experimental hall. They're also running some experiments here and we're gonna go take a look At the very end of LCS. You'll find four more hus, these ones are color coded and more fancy acronyms. Speaker 6: This [00:10:00] is MFX, which is the macro molecular femtosecond crystalography Hutch. And here we look at, uh, proteins viruses, biological material in air. Speaker 1: This is really cool behind me. There's four lasers in here. Now those lasers generate beams that are directed through. There's a series of optics right there that you can see after getting directed through this optics. They pass [00:10:30] through this black tube here into this chamber, also known as the MEC or matter in extreme condition. Hu. Now in that chamber, the scientists can use those lasers to simulate all sorts of extreme conditions. Anything from the core of the earth, to the surface of the sun, after generating these extreme conditions, researchers use x-rays from LCS to capture images of how materials inside the chamber react in those exact moments Speaker 6: Weaken for focus on planetary interiors, [00:11:00] we can focus on, um, impact or collision events. So maybe the moon forming impact simulation we're generating high density plasmas much like our in the, the interior of stars. And we can watch what is happening on a very at timescale to these very hot dense plasmas. We also focus on a portfolio of material science applications, so considering materials at extreme conditions, what happens [00:11:30] to the surface of a reentry vehicle Speaker 1: While most scientists at slack are eagerly awaiting the activation of LCS. Two science to here at F Fe are looking even further into the future. Often referred to you as the upgrade to the upgrade. LCLs two high energy is a project that will expand energy reach on the new line. Speaker 6: It means we can penetrate deeper into samples. We can look at more complicated materials. Think about the Earth's core made of iron Speaker 1: [00:12:00] In total. The upgrade for L C LS two runs about a billion dollars. Now in just a couple weeks, scientists are hoping to cool down those cryo modules that we saw earlier and then produce their first electron beam with LCS two. Then in summer of 2022, hopefully their first x-ray, which they'll call their first big light event. That's gonna be just in time for the 60th anniversary of slack. I'm Andy Altman. Thank you so much for watching. Don't forget to like, and subscribe if you [00:12:30] enjoy this video and I'll see you in the future.