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12  PSI-XFEL

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,

–14

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

Aramis

optics” techniques, such as heterodyne spectroscopy. Finally,

Porthos

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

57

Ge Fe

magnetism, correlated e-

high-resolution spectroscopy Mg

Al

Si

P

Mn Fe

C

N

Bi

U

I La Ce Gd Ta W Pt Bi

O

water window

100

Cu

solution chemistry

Na M g Al Si P S

1000

Ca

Fe GaGeAs

proposed XFEL experiments of particular interest to PSI research divisions.

M edges 3

L edges 3

K edges

Nanoscale magnetic processes

104

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

elements.

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

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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...