Résumés des cours

Abstract of lectures :

Lectures are given in english

Sergio Di Matteo
Synchrotron radiation-matter interaction

The first part of the lecture is devoted to the introduction to synchrotron radiation (what is it ? how is it produced ? what is it useful for ?): this description will be kept qualitative, in order to introduce the main features of synchrotron radiation.
In the second part, the theoretical description of matter-radiation interaction is aborded. We shall mainly focus on the way the scattering cross-section is derived, showing the theoretical difference between 'first-order processes' (absortion, emission, etc.) and 'second-order processes' (scattering). Some examples are discussed.

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Sylvain Ravy
From amorphous to crystals: X-ray scattering

In this lecture we will recall the basic concepts of X-ray diffraction : the scattering cross-section, the scattering vector and the use of the Fourier space to interpret scattering experiments. The different types of order in condensed matter will be introduced (liquids, amorphous, liquid crystals, periodic and aperiodic crystals), along with their signature on X-ray patterns. Classical techniques on powder and single crystals will be recalled, with an emphasis on synchrotron radiation specificities. Finally, an introduction to the use of the beam coherence will be presented.

Rajmund Mokso
Imaging and micro-tomography

The first part of the lecture will be dedicated to explaining the basics of imaging with partially coherent hard X-ray radiation. The focus will be on tomographic microscopy that can result in a 3D electron density map of the studied object. The concepts of absorption and phase imaging will be explained highlighting the current challenges and future perspectives regarding instrumentation development and reconstruction algorithms.
In the second part I demonstrate the cutting-edge 3D techniques for high spatial and temporal resolution X-ray imaging on selected applications. This part will also include an introduction to quantitative 3D and 4D (space and time) image analysis approaches.

David Keen
Probing structure over different length scales: using total scattering and the PDF to characterise disorder in complex crystalline materials

Modern materials are increasingly displaying structures that are neither fully long-range ordered nor merely ordered over short length-scales; they show a mix of structural features that are correlated over different distances. Their complex structures are a challenge to characterise using the established norms of crystallography and over the past 25 years new techniques have been successfully developed to address them. In the main, these approaches rely on so-called 'total scattering' or 'pair distribution function' data from diffractometers at neutron spallation or x-ray synchrotron sources. This course will describe all aspects of this important area of crystallography, starting with the measurements themselves, the importance of robust data correction (and some of the theory that underpins it) and the two principle methods of data analysis and interpretation (namely PDFFIT and reverse Monte Carlo). I will use many examples throughout the course to show the methods in practice and will discus various issues including the benefits of using x-ray synchrotron and/or neutron data, the challenges associated with tackling nanocrystalline materials and the recent developments to the RMC method for the study of molecular systems. Finally I will use the analysis of total scattering data to introduce, in general terms, the more established method of single crystal diffuse scattering and will discuss the advantages and disadvantages of using such data for investigating structural disorder.

Gerardina Carbone
Surface diffraction technique up to the nano-scale

In this lecture I illustrate different synchrotron based diffraction techniques to investigate crystal structure and strain in low-dimensional systems, with the support of relevant examples. The first part is dedicated to the description of surface-sensitive techniques for the characterisation of thin films and of nanostructure ensembles. In the second part I will discuss the use of (coherent) nanobeams as /local probe /for the investigation of single nanostructures as compared to ensemble average measurements, as well as to obtain high-resolution maps of morphology, strain or composition of complex systems.

Eric Collet
Time resolved studies: from femtoseconds to mins

A new challenge has emerged in material science to direct the functionality of matter by light excitation on the relevant time scale. Recent years have seen terrific successes in providing atomic level views of transient phenomena in inorganic, molecular and even biomolecular systems. The field of dynamical structural science is truly interdisciplinary in nature. The time-scales of interest span also a broad range, from 100 fs atomic motion dynamics to slower (µs) molecular diffusion and ms relaxation processes of transient excited states. Finally the different natures of the probes (X-ray and electron) and of the techniques (spectroscopy and scattering/diffraction) lead to complementary signals, which can be combined in comprehensive studies. It is now possible to elucidate transient states of matter hidden, and sometimes coexisting, in the time domain.

Franck Artzner
Small Angle X-ray Scattering (SAXS): from soft matter to metallurgy

Most of life materials (food, cosmetic) reveal a large variety of organizations, which are neither amorphous nor crystalline. These materials are organized by self-assembly of proteins, lipids, organic molecules and inorganic nanoparticles. The X-ray Diffuse Scattering is a powerful technique to characterize order and disorder in such materials. Their characteristic sizes are between a few Angtroems and hundreds of nanometers. In this case the scattering can occur at Small Angle (less than 1°) and we speak about Small Angle X-ray Scattering.

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