Page 14


PSI Scientific Report 2008

Novel science at the PSI-XFEL

Bruce Patterson, Rafael Abela, Free Electron Laser Project (PSI-XFEL), PSI Kurt Ballmer-Hofer, Molecular Cell Biology, PSI, Laura Heyderman, Laboratory for Micro- and Nanotechnology, PSI; Chris Milne, Laboratory for Synchrotron Radiation, PSI and EPFL, Lausanne; Urs Staub, Pierre Thibault, Laboratory for Synchrotron Radiation, PSI

The PSI X-Ray Free Electron Laser (XFEL) facility will offer possibilities for novel science in condensed matter physics, chemistry and biology. The advantage of the XFEL over visible lasers and X-ray synchrotrons is the combination of short wavelength (0.1 – 10 nm), short pulse duration (<20 fs), high peak brightness, and high coherence. These properties will allow observations of time-dependent behaviour at the atomic level.

Scientific strengths of the PSI-XFEL

down to atomic resolution. Although a focused XFEL pulse will locally destroy the sample, the short pulse duration will ensure

The photon energies of the PSI X-ray Free Electron Laser (XFEL)

that the scattered photons reaching the detector arise from

[1] will allow a wide range of investigations of matter at the

undamaged material. Variable-polarization undulators at the

molecular and atomic level (see Figure 1). Furthermore, the

PSI-XFEL will allow observation of magnetization dynamics,


s) and high

using the magnetic contrast of the L absorption features of,

peak flux (1011 photons/pulse) will permit the study of ultra-

for example, Fe, Co and Ni. Interesting magnetic processes

fast dynamics, either as equilibrium fluctuations or in “pump-

may be efficiently initiated at the PSI-XFEL with picosecond,

probe” experiments. XFEL-radiation has 100% transverse

half-cycle pulses of intense terahertz (THz) radiation, produced

coherence, allowing “lensless imaging” of nanostructures,

by a dedicated source, synchronized with the XFEL. The same

extremely short X-ray pulses (<20 fs = 2  10

THz source may also initiate surface catalytic reactions. It is also planned that the PSI-XFEL will deliver highly uniform, grating optics

crystal optics

“transform-limited” X-ray pulses, suitable for novel “quantum


optics” techniques, such as heterodyne spectroscopy. Finally,


the maximum photon energy of the PSI-XFEL may be suffi-

crystal diffraction

Arthos (seeded) d'Artagnan

ciently high to reach the ultra-narrow (10–8 eV) “Mössbauer

bio nanocrystals cell imaging

resonance” of the 57Fe nucleus, yielding the ultimate in highcoherence X-rays. In what follows, we briefly present three

stable Mössbauer isotopes 73


Ge Fe

magnetism, correlated e-

high-resolution spectroscopy Mg




Mn Fe





I La Ce Gd Ta W Pt Bi


water window



solution chemistry

Na M g Al Si P S



Fe GaGeAs

proposed XFEL experiments of particular interest to PSI research divisions.

M edges 3

L edges 3

K edges

Nanoscale magnetic processes


Photon Energy [eV]

Very stable “magnetic vortices” in planar magnetic nanostructures may in the future be used for high-density information

Figure 1: The range of photon energy spanned by the beamlines

storage. Field-induced switching of the core of such a vortex

of the PSI-XFEL. Also indicated are preferred ranges for studying,

is predicted to occur on the nm and ps length and time scales

for example, organic materials in aqueous solution (“water

[2] (see Figure 2). With the high transverse coherence and the

window”), magnetism and correlated electron materials, and biological material in cellular and crystalline forms. The “M, L

circular polarization of the PSI-XFEL beam, and at photon

and K edges” refer to resonant energies of particular atomic

energies close to the magnetically-sensitive L2 and L3 edges


of, for example, cobalt (at 793 and 778 eV, respectively), it

Profile for Paul Scherrer Institut

Scientific Report 2008  

The whole range of PSI's research in more than 100 pages – this is what the new Scientific Report has to offer. Examples of the latest scien...

Scientific Report 2008  

The whole range of PSI's research in more than 100 pages – this is what the new Scientific Report has to offer. Examples of the latest scien...