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Struktur und Dynamik Poster: Mi., 14:00–16:30 M-P118
Ultrafast X-ray diffraction experiments at the linear accelerator based
X-ray source SPPS
Christian Blome 1 , Thomas Tschentscher 1
1 DESY, Notkestr. 85, 22607, Hamburg
The development of new X-ray sources like free electron lasers, 4th generation synchrotrons
and laser driven plasmas will provide new opportunities for producing short
pulses with short wavelength radiation. These ultrashort X-ray pulses offer a unique
combination of spatial and temporal resolution and thus make it possible to directly
observe atomic motion, for example during chemical reactions or phase transitions.
Using the Sub-Picosecond Pulse Source in Stanford, USA the collaboration has applied
optical pump X-ray probe techniques to various problems in physics with a time
resolution of 100 fs. SPPS is the first linear accelerator based femtosecond multi keV
X-ray source and stands in the forefront for research, in particular to conduct important
RD work for accelerator concepts, X-ray optics, and experimental techniques for
future X-ray FEL experiments. In this contribution we will give an overview of the
activities at the SPPS.
We will discuss preliminary results of the ionic to neutral phase transition in the
typical mixed stack charge transfer compound TTF-CA. We compare results from the
SPPS and discuss them in the context of the time resolved data from the ESRF, ID09
with 50 ps time resolution [1]. We present results of the non-thermal melting of a semiconductor
after short pulse laser excitation [2] and first measurements of the detection
of optical coherent phonons in laser excited Bismuth [3]. Beyond physics we discuss
the crucial question how to time a linac based source with an optical pump laser [4].
[1] E. Collet et al., Science 300, 612-615, 2003
[2] A.Lindenberg et al., Science 308, 392-395, 2005
[3] K. Sokolowski-Tinten et al., Nature 422, 287-289, 2003
[4] A. Cavalieri et al., Physical Review Letter 94, 1148011, 2005