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SLAC creates new opportunities in ultrafast science by building one of the world's fastest "electron cameras"

Scientists at SLAC, including PULSE PIs, Markus Guehr, Ryan Coffee, Alan Fry, and Aaron Lindenberg, have built a new scientific instrument that allows researchers to observe the motion of electrons and atomic nuclei at incredibly short timescales - less than a tenth of a trillionth of a second. This instrument relies on a method called Ultrafast Electron Diffraction, where scientists are able to capture subtle differences in the diffraction patterns of electron waves that scatter off atomic nuclei and electrons as they pass through a sample. The diffraction patterns are then combined to reconstruct ultrafast motions of the sample's interior structure. 

To see the full article published on the SLAC website, please follow this link.

To read the full text of the article published in the journal, Review of Scientific Instruments, please follow this link.

PULSE graduate student to defend thesis on August 12

PULSE graduate student, Crystal Bray, a Ph.D. candidate in the Applied Physics department and a member of David Reis's group, will defend her thesis entitled, "Photon Energy and Carrier Density Dependent Dynamics of Electron Excited States Probed by Coherent and Squeezed Phonons in Select A7 Structures". Her defense will take place on Wednesday, August 12, 2015 at 9 am in the Paul Allen Building, Room 101X. Her abstract is printed below. 

The interaction of intense femtosecond laser pulses with matter lead to highly excited transient states far from equilibrium. The dynamics of these excited states relate to many applications from laser machining to energy conversion. Ultrafast optical and x-ray light-scattering has emerged as a powerful experimental method to study material dynamics on the time-scale of atomic and even electronic motion. Here I report results of ultrafast coherent and squeezed phonon scattering experiments in bismuth and antimony. In response to laser generated coherent phonon scattering, I find the zone-center A1g vibrational mode greatly dependent on non-thermal electronic band-occupation. And in response to x-ray generated squeezed phonon scattering, I find anisotropic changes in dynamical forces evidenced by differentiated high wavevector acoustic mode softening. These results advance our understanding of microscopic electron-electron and electron-phonon interactions in transient systems. 

PULSE Director and Advisory Board member publish article in Physics Today

Phil Bucksbaum, PULSE Director, and Nora Berrah, PULSE External Advisory Board member and Professor of Physics at the University of Connecticut, published an article this morning in the journal Physics Today about the exciting new research and developments produced by x-ray free electron lasers (XFELs) around the world including the Linac Coherent Light Source (LCLS) here at SLAC. The piece, entitled, "Brighter and Faster: The promise and challenge of the x-ray free election laser", takes an in depth look at how XFELs have enabled scientists to explore uncharted fields of research and apply their findings to a variety of fields including commercial drug development and the engineering of jet turbine blades.

A full text of the article can be viewed here.

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