BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:3
UID:UW-Physics-Event-4941
DTSTART:20190426T203000Z
DURATION:PT1H0M0S
DTSTAMP:20260419T084735Z
LAST-MODIFIED:20190424T133345Z
LOCATION:2241 Chamberlin Hall
SUMMARY:New Science Opportunities at X-ray Free Electron Lasers \, Phy
sics Department Colloquium\, Uwe Bergmann\, Stanford PULSE Institute\,
SLAC National Accelerator Laboratory
DESCRIPTION:Over the past century X-rays have revolutionized numerous
fields of science. Starting in the 1970s powerful new synchrotrons sou
rces have dramatically advanced the scientific use of X-rays. In the l
ast decade new X-ray free electron lasers\, such as the Linac Coherent
Light Source (LCLS) at SLAC National Accelerator Laboratory\, have co
me to light. These coherent X-ray sources produce ultra-short pulses w
ith a brightness that is ten billion times larger than synchrotron sou
rces. For the first time scientist can study matter not just at the le
ngth scale of atoms and molecules\, but also at the time scale of mole
cular motion. We will describe these machines and present some example
s of recent X-ray laser research.
\nOne example is our recen
t work on stimulated x-ray emission spectroscopy. Here\, we have creat
ed inner shell x-ray fluorescence laser signals from manganese compoun
ds. To achieve this exponential signal gain\, we used highly focused u
ltrashort x-ray pump pulses from LCLS. The observed signal consisted o
f very short x-ray pulses up to 10^6 times stronger than normal x-ray
fluorescence. Remarkably\, these x-ray pulses preserved the small diff
erences in fluorescence energy\, caused by the different chemical surr
ounding of the manganese ions. We describe the phenomena and how we pl
an to apply this and similar approaches to learn more about transition
metal systems and their function in catalysis\, chemical\, and materi
als science.
\n
URL:https://www.physics.wisc.edu/events/?id=4941
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