The world's most powerful X-ray laser equipment will be put into use in 2023

At the beginning of 2023, electrons flying near the speed of light in the California underground tunnel will produce the brightest X-ray ever on the earth, enabling scientists to study atoms and molecules in unprecedented detail.

These record breaking X-rays will be produced in SLAC National Accelerator Laboratory, which has recently upgraded its linear accelerator coherent light source (LCLS) X-ray laser, making it the fastest and brightest X-ray laser in the world.

The SLAC National Accelerator Laboratory of the US Department of Energy is working hard to enhance the capability of its linear accelerator coherent light source (LCLS) X-ray free electron laser (XFEL), which is an instrument designed to capture images of microscopic objects with high resolution and ultra fast time scales. By using a modern ultra intense optical laser pulse technology called chirped pulse amplification (CPA), the SLAC team has designed a system that can generate X-ray pulses ten times stronger than before, all within the existing free electron laser infrastructure of LCLS.

The team recently published their research results in Physical Review Letters.

(Image source: SLAC National Accelerator Laboratory)

By amplifying the chirped pulse of X-ray, researchers can achieve very influential beam parameters with peak power greater than 1 terawatt, and the pulse duration is about 1 femtosecond.

LCLS works like an atomic resolution camera, taking snapshots of the smallest changes in molecules and materials in an extremely short Nth of a second. The ultrabright and ultrafast X-ray pulses generated by it are very attractive for many applications and scientific research fields, such as biomolecular dynamics, laboratory astrophysics research and observation of how photons interact with matter.

However, increasing the laser power will make the laser pulse time inconsistent. This inconsistency in turn creates a distorted or inaccurate impression of what is happening in the system - something scientists desperately want to avoid. The existing solutions greatly reduce the laser power and limit the research of researchers.

Due to these limitations, "more than 90% of XFEL laser experiments in the past decade have used X-ray sources like ultrafast flashlights," said Diling Zhu, senior scientist of SLAC and senior co-author of the study. "Few people really use it the way we use optical lasers. We are just beginning to learn how to manipulate X-ray beams, as we have done with optical lasers for decades."
Chirped pulse amplification (CPA) technology was originally designed to increase the power of optical laser. Its working principle is to extend the duration of energy pulse before it passes through the amplifier and compressor, and finally form a super strong, clear and ultrashort pulse.

Donna Strickland and G é rard Mourou, physicists from the University of Rochester, invented the chirped pulse amplification (CPA) technology in the 1980s, and won the 2018 Nobel Prize in physics. Although CPA has completely changed the generation of high-energy pulses of optical lasers, this technology has proved difficult to adapt to the X-ray wavelength.

In the above research, researchers have designed a CPA method through detailed numerical simulation, which is used to generate high intensity hard X-ray pulses within the beam parameters of existing free electron lasers. Based on their new system, scientists can use existing free electron laser equipment to generate terawatt femtosecond hard X-ray pulses.

Source: OFweek