What research is planned for the ASU CXFEL?

At Arizona State University, we have big plans to use the compact X-ray light source and compact X-ray electron laser for medical imaging, making biomolecular movies, unraveling photosynthesis, chemical catalysis and attosecond physics.

We will use the compact X-ray light source — phase one of the project — for phase-contrast medical imaging. These images are capable of examining soft tissues in the body, including patient biopsy samples of cancer patients, with unprecedented resolution. ASU is collaborating with Mayo Clinic to study and apply phase-contrast imaging for next-generation diagnosis of disease.

The most important area for ASU research is Petra Fromme’s time-resolved studies of biomolecules “in action.” All processes in nature are highly dynamic, but so far we have only static pictures of the molecules that drive life on earth.

The new CXFEL technology solves the century-old challenge of structure determination: X-rays damage biomolecules. So the same methods that were used to interrogate the structure of the biomolecules destroyed them. With the short CXFEL pulses, ASU scientists follow reactions of biomolecules in real time without any damage, as the pulses are so short that movie frames are recorded before any destructions take place.  

We use new technology to study the cause of disease at the atomic level, with the goal to unravel the mechanism of how cancer cells can divide unchecked and how molecules allow pathogens to infect human cells. The goal is to block their destructive action by development of novel drugs, with tight, very specific binding that kills cancer cells or pathogens without harming healthy cells.

We are studying photosynthesis, which supplies the energy for all higher life on earth by converting the light from the sun into chemical energy. All the oxygen we breathe, all the food we eat and all the fossil fuels on earth are generated by this process.

Our goal is to understand the mechanism of photosynthesis at the atomic level toward a molecular movie of how plants capture the light and split water to generate oxygen with only proteins and earth-abundant metals. Once we discover nature’s secrets to produce unlimited energy from sunlight, we can build systems as efficient as nature designs and as stable as man-made ones.

Through chemical catalysis, we aim to understand at the atomic level how molecules are formed and study materials. This is a new frontier involving very subtle effects in materials at the quantum level that cause them to display unique characteristics and behavior. These studies will lead to clean, new synthesis pathways for chemical and materials with amazing new features, such as strong but biodegradable plastic, very flexible building materials and even the further miniaturization of semiconductor chips for information technology.

We aim to use our second-generation instrument: the compact X-ray free electron laser in attosecond physics. Here, ASU researchers will examine how molecules connect with each other and study the dynamics of ultrafast dynamics at a previously impossible time speed. With attosecond-pulse duration, we will explore the unknown, looking at the dynamics of the fastest processes in nature as well as nano and quantum materials. This research could lead to the development of superconductivity at room temperature, which could have a profound effect on energy use and contribute to the development of quantum computing. The CXFEL is a precise probe for such investigations.

The CXFEL project uses lasers from the photoinjector to the experimental end stations. Our devices push the boundaries of what is possible with current laser and optical technology. This is critical for getting the most out of our X-ray sources. 

The average cost per watt of high-power lasers is halved almost every year, making technologies that were almost unaffordable a few years ago cost-effective solutions for the future. Our ultrafast X-ray sources are complemented by exciting samples with everything from few-cycle lasers to THz radiation.  

The hard X-rays of the new CXLS will be ideal for looking at the role atomic structure plays in the fundamental physics behind materials. The details behind thermal transport in high-power electronics and solar cells are much clearer with X-ray probes. 

These probes can explore fluctuations and deviations from the average structure, and X-rays are ideally suited to track the details of light-driven structural phase transitions. Such transitions are important to understanding solid-state memory and quantum many-body systems.  

The period of a single cycle of visible light is about three femtoseconds. As a sub-femtosecond source, the future CXFEL is designed to directly reveal how electrons move under visible excitation in materials. 

The soft X-rays that CXFEL is slated to produce can probe electronic excitations and spatial patterns of transition-metal compounds from magnetic materials to superconductors. These X-rays also push the time resolution of soft X-rays to the attosecond regime. The increased speed will enable researchers to see the electrons of transition-metal compounds in action. 

Who are the scientists involved in the CXFEL project?

Robert Kaindl directs the CXFEL program at Arizona State University. His research involves creating and applying laser techniques across the spectrum of light. At Biodesign and as a professor in the ASU Department of Physics, he will pursue new frontiers of light-driven materials phenomena.

The CXFEL accelerator itself is the brainchild of physicist and associate professor William Graves, who has worked on the design and construction of particle accelerators for 30 years. He holds four patents on X-ray light source technology and is also the designer and builder of the compact X-ray light source (CXLS) of the CXFEL project.

Petra Fromme is an ASU Regents Professor and director of the Biodesign Center for Applied Structural Discovery, as well as the scientific director of the NSF BioXFEL Science and Technology Center. She pioneered ultrafast X-ray science at the big XFELs along with the late John Spence. Among the core bioscience applications envisioned for the CXFEL Lab’s machines are static and time-resolved crystallography investigations by Fromme’s center. This research will allow scientists to produce movies of biomolecules in action — for example, drugs binding to receptors at the surface of cells.

Fromme’s team is known internationally for various breakthroughs. In 2012, Fromme and collaborators determined the 3D structure of a protein for the first time using a technique they developed called femtosecond nanocrystallography. In 2014, they published a study showing the first snapshots of photosynthesis in action as it split water into protons, electrons and oxygen. More recently, the team has used the technology to:

  • Capture the first images of crystal structures related to the biochemical pathways that allow us to breathe.
  • Identify a riboswitch that opens up the possibility of using bacterial mechanisms to fight human disease.
  • Determine the structure of rhodopsin, a molecular complex responsible for our sense of sight.
  • Reveal the fine details of how an experimental drug works to regulate blood pressure, paving the way to develop new hypertension drugs.