Hard X-ray flash breaks speed record

April 10, 2018, US Department of Energy
While it looks like a graffiti mark, this is a picture of an ultrashort pulse of a photon beam. This pulse of hard x-rays was produced using two methods developed at SLAC’s Linac Coherent Light Source

Reactions in solar panels, catalytic converters, and other devices are governed by the quick motion of electrons. To capture the movement of these electrons, scientists use pulses of extremely high energy x-rays. The challenge is making the pulses short enough to get a good look at the electrons. Now, the shortest-ever pulses of hard x-rays were produced using two methods developed at SLAC's Linac Coherent Light Source. The pulse duration is just a few hundred attoseconds long, or billionths of a billionth of a second. It set a record for hard x-rays produced by free-electron lasers.

With the availability of these ultrashort hard x-ray pulses, scientists have a new tool to capture the fast motions of on the atomic or molecular scale. These tools push the frontiers of research into chemical reactions and magnetic processes that involve ultrafast electrons.

To capture the fast motions of electrons that govern many chemical processes, x-ray pulses in the attosecond range are required. Two methods have been developed at the Linac Coherent Light Source, both manipulating the tightly packed bunches of electrons produced by the SLAC linear accelerator. These methods have been used to generate hard pulses only a few hundred attoseconds long for the first time. The are shortened by either using nonlinear compression of the electron bunch or by passing the bunch through a slotted metal foil.

In these two configurations, only a small part of the bunch is selected to lase. Thus, the emitted x-ray laser light has a much shorter length. The schemes leverage the existing x-ray free-electron laser facilities and provide new capabilities for ultrafast x-ray sciences. Due to the nature of how free-electron laser pulses are produced, these schemes only yield attosecond pulses in the hard x-ray domain.

Extensions to soft x-rays, which are important for chemical science studies, are the subject of a new project called XLEAP, based on optical laser modulation methods, with testing now underway at the Linac Coherent Light Source.

Explore further: Major technology developments boost LCLS X-ray laser's discovery power

More information: S. Huang et al. Generating Single-Spike Hard X-Ray Pulses with Nonlinear Bunch Compression in Free-Electron Lasers, Physical Review Letters (2017). DOI: 10.1103/PhysRevLett.119.154801

A. Marinelli et al. Experimental demonstration of a single-spike hard-X-ray free-electron laser starting from noise, Applied Physics Letters (2017). DOI: 10.1063/1.4990716

Related Stories

Magnetic trick triples the power of SLAC's X-ray laser

February 5, 2018

Scientists at the Department of Energy's SLAC National Accelerator Laboratory have discovered a way to triple the amount of power generated by the world's most powerful X-ray laser. The new technique, developed at SLAC's ...

Attoseconds break into atomic interior

February 27, 2018

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons ...

Electrons fingerprint the fastest laser pulses

September 8, 2016

Analyzing ultrafast chemical processes requires ultrafast lasers—light pulses lasting for mere attoseconds (10-18 second)—to act as a "stop-motion" strobe camera. Physicists at the University of Nebraska-Lincoln are analyzing ...

A Bunch of Electron Chicanery

November 21, 2006

As the Linac Coherent Light Source (LCLS) takes shape over the next few years, one of the key issues occupying the minds of physicists is controlling the size and shape of the electron pulses used to generate the x-ray laser ...

Recommended for you

ATLAS experiment observes light scattering off light

March 20, 2019

Light-by-light scattering is a very rare phenomenon in which two photons interact, producing another pair of photons. This process was among the earliest predictions of quantum electrodynamics (QED), the quantum theory of ...

How heavy elements come about in the universe

March 19, 2019

Heavy elements are produced during stellar explosion or on the surfaces of neutron stars through the capture of hydrogen nuclei (protons). This occurs at extremely high temperatures, but at relatively low energies. An international ...

Trembling aspen leaves could save future Mars rovers

March 18, 2019

Researchers at the University of Warwick have been inspired by the unique movement of trembling aspen leaves, to devise an energy harvesting mechanism that could power weather sensors in hostile environments and could even ...

Quantum sensing method measures minuscule magnetic fields

March 15, 2019

A new way of measuring atomic-scale magnetic fields with great precision, not only up and down but sideways as well, has been developed by researchers at MIT. The new tool could be useful in applications as diverse as mapping ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.