Temperatures in California are warmer than space thanks to a superconducting X-ray laser

Temperatures in California are warmer than space thanks to a superconducting X-ray laser ...

Temperatures of today are colder than those of outside space, thanks to a particle accelerator that crushes electrons together here on Earth.

A rayfree-electron laser used at the Department of Energy''s National Accelerator Laboratory is part of a project to the Linac Coherent Light Source (LCLS), which was later called LCLS II scientists, chilled liquid helium to a lesser degree of Fahrenheit (minus 271 degrees Celsius).

That''s only 2 kelvins above absolute zero, the coldest temperature at which all particle movement is suspended.

The accelerator is required for this frosty environment, because at such low temperatures the machine becomes superconducting, meaning it may increase electrons through it with just about zero energy loss.

Even empty spaces of space aren''t this cold, as they are still filled with cosmic microwave background radiation, a remnant from shortly after theBig Bang that has a uniform temperature of minus 454 F (minus 271 C) or 3 K.

"The LCLS-II X-ray free-electron laser''s next-generation superconducting accelerator has reached its operating temperature of two degrees above absolute zero," Andrew Burrill, director of the SLAC''s Accelerator Directorate, said on Live Science.

He added that LCLS-II is preparing to begin accelerating electrons at one million pulses per second, putting the world record.

"This is four times greater pulses per second than its predecessor, LCLS, indicating that in just a few hours, we will have sent more X-rays to users [who aim to use them in experiments] than LCLS has done in the past ten years." Burrill said.

This is one of the last milestones that LCLS-II must impose before it can go on to produce X-ray pulses that are 10,000 times brighter than their predecessors.

This should assist researchers in processing complex materials in unprecedented detail. The high-intensity and high-frequency laser pulses enable researchers to see how electrons and atoms in materials interact with unprecedented clarity.

This will be of a wide spectrum of applications, from revealing "how natural and man-made molecular systems transform sunlight into fuels," to thus understanding how to control these processes, to understanding the fundamental properties of materials that will enable quantum computing.

Related:10 cosmic mysteries the Large Hadron Collider might unravel

Making freezing gradients inside the accelerator required some work. For example, the team required even greater pressures.

According to Live Science, Eric Fauve, the director of the Cryogenic Division at SLAC, pure water boils at sea level (100 C), but this boiling temperature differs with pressure.

Pressure in a pressure cooker is higher, and water boils at 250 F (121 C), while the reverse is true at altitude, where pressure is lower, and water boils at a lower temperature.

"For helium, it''s very much the same. However, at atmospheric pressure, helium will boil at 4.2 degrees Celsius; this temperature will decrease if pressure decreases," Fauve said.

"To reduce the temperature to 2.0 kelvin, we need to have a pressure of just 1/30 of atmospheric pressure."

The team uses five cryogenic centrifugal compressors that compress the helium to cool it and then allow it to expand in a chamber to lower pressure, making it one of the few places on Earthwhere 2.0 K helium can be produced on a large scale.

Fauve explained that each cold compressor is a centrifugal unit equipped with a rotor/impeller similar to that of an engine turbo-compressor.

"While spinning, the impeller accelerates the helium molecules, creating a vacuum at the center of the wheel where molecules are sucked, generating pressure at the wheel''s periphery, which is where molecules [are] ejected.

Compression forces the helium to take its liquid state, but the helium escapes into this vacuum, where it expands rapidly, cooling as it does so.

The ultra-cold hydrogen produced at LCLS-II is a scientific experiment in itself, outside its ultimate applications.

"At 2.0 kelvin helium becomes a superfluid, helium II, that has extraordinary properties," Fauve said. For example, it conducts heat hundreds of times more efficiently than copper, and it has so little viscosity or resistance to flow that this is cannot be measured.

2 Kelvins are expected to fall, according to LCLS-II.

"Today, very high-end cooling systems can achieve light temperatures, achieving a fraction of a degree above zero, where every movement stops," Burrill said.

According to a spokesperson, this particular laser does not have the ability to reach those extremes.

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This article was originally published by Live Science. Read the whole article here.

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