Seminars

High-repetition rate laser pump/X-ray probe experiments at the APS

by Eric Dufresne (Advanced Photon Source, Illinois, USA)

Friday, June 7, 2013 from to (Europe/Berlin)
at AER19/4.14
Description
When a short-pulse laser beam is absorbed in a crystal, the heat or large electric field can induce time-dependent strain waves which propagate in the material at the speed of sound. At a synchrotron, the repetition rate of the X-ray source (MHz) and the laser (kHz) is often mismatched by several orders of magnitude leading to a very inefficient use of the X-ray probe beam. In this presentation, I will show how one can synchronize a femtosecond 88 MHz Ti:Sapphire laser to the APS running at the same repetition rate in 324-bunch mode. This efficient use of the X-rays enabled us to measure coherent diffraction patterns from nanoparticle of ZnO as a function of the Bragg angle and time delay between the laser-pump and X-ray probe beams. Performing high-repetition laser pump/x-ray probe experiments is a key technique that will be used with the APS Short-Pulse X-ray source. I will conclude with an overview of the progress made towards the generation of high-repetition rate picosecond x-rays in the scope the APS Upgrade project.
Organised by Thomas Tschentscher