Data Science

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Super-Resolution X-ray Microscopy unveils the buried secrets of the nanoworld

A novel super-resolution X-ray microscope developed by a team of researchers from the Paul Scherrer Institut (PSI) and EPFL in Switzerland combines the high penetration power of x-rays with high spatial resolution, making it possible for the first time to shed light on the detailed interior composition of semiconductor devices and cellular structures.
The first super-resolution images from this novel microscope will be published online July 18, 2008 in the journal Science.

Nanoscale depth resolution of lattice dynamics

We employ grazing-incidence femtosecond x-ray diffraction to characterize the coherent, femtosecond laser-induced lattice motion of a bismuth crystal as a function of depth from the surface with a temporal resolution of ~200 fs. The data show direct consequences on the lattice motion from carrier diffusion and electron-hole interaction, allowing us to estimate the effective diffusion rate for the highly excited carriers and the electron-hole interaction time.

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Coherent Diffraction Imaging Using Phase Front Modifications

We introduce a coherent diffractive imaging technique that utilizes multiple exposures with modifications to the phase profile of the transmitted wave front to compensate for the missing phase information.

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X-ray dark-field imaging using a grating interferometer

A type of X-ray imaging that shows detail otherwise lost, and which is compatible with conventional radiography instrumentation is now feasible, reports a study published online in Nature Materials. This technique offers unprecedented resolution for several applications, including medical imaging, security screening and industrial non-destructive testing.

Stable Source of Femtosecond X-Ray Pulses at SLS – Pushing atoms on a swing

The typical time scale of atomic motion during fundamental physical processes such as phase transitions in solids or molecular dynamics in chemical reactions ranges from ten to hundreds of femtoseconds. The direct observation of these processes on an atomic length scale therefore requires utrashort light pulses at wavelengths capable of resolving the underlying atomic structures.

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Pushing atoms on a swing

The typical time scale of atomic motion during fundamental physical processes such as phase transitions in solids or molecular dynamics in chemical reactions ranges from ten to hundreds of femtoseconds. The direct observation of these processes on an atomic length scale therefore requires utrashort light pulses at wavelengths capable of resolving the underlying atomic structures.

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The conducting meat in the insulating sandwich

In 2004, it was discovered that when a layer of LaAlO3 (LAO) is in contact with a layer of SrTiO3 (STO), an ultrathin layer of highly conducting material is formed where they contact one another, despite the fact that both LAO and STO are insulators. The underlying physics responsible for this phenomenon is still much disputed, despite a worldwide concerted research drive since then to explain it.

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The exciting story of TiSe2

In this story of TiSe2, experiment and theory meet to provide an explanation for a long-standing enigma. In this system, the electrons rearrange themselves spontaneously at low temperature, resulting in a new periodicity from that of the original lattice. This phase change is driven by a decrease in the total energy of the system. However, the nature of this transition has been a matter of controversy for a long time.

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Is Smaller Stronger?

In 2004 researcher discovered that a single crystalline metal is stronger when the sample volume is reduced to the micron or even submicron range. In an ongoing debate on the origin of this phenomenon classical deformation theories are questioned. The suspicion that structural defects, i.e. deviations from perfect crystalline structure would play an important role in the smaller is stronger effect, could not be verified because of the lack of an appropriate measuring technique.

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Making the invisible visible

Using x-rays scientists have learned to make the invisible visible. Since almost 100 years doctors use the difference in x-ray absorption between bones and tissue to diagonose their patients.

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A virus in a nutshell

Nature has found remarkable ways to protect sensitive objects. One example is the seed of a nut which is protected by its shell. Another are viruses from the cypovirus family. They are hidden inside tiny natural crystals where they can survive harsh conditions until they meet their target, the gut of the silkworm. Here the virus is released from the crystal causing a virus infection of the worm. Researchers have now unraveled the structure of these natural protein crystals.