Abstract
The name of the X-TOP conferences originates from the first x-ray topography-related meeting, held in Grenoble in 1990, which aimed to define the ESRF beamline devoted to diffraction topography. X-TOP conferences took place in Marseille (France) 1992, Berlin (Germany) 1994, Palermo (Italy) 1996, Durham (UK) 1998 and Ustron-Jaszowiec (Poland) 2000. These conferences extended the topics well beyond `topography' and incorporated other imaging and diffraction techniques (high resolution and grazing incidence diffraction, reflectometry, microtomography, phase contrast imaging), which emerged or developed in strong connection with the availability of SR sources.
We wish to dedicate the X-TOP 2002 conference to the memory of Professor Norio Kato (1923-2002). Professor Kato brought about outstanding developments of the dynamical theory of x-ray diffraction in perfect and deformed crystals. He established, in addition, many of the basic concepts necessary for the interpretation of x-ray topographs. Professor A Authier was invited to review Norio Kato's career and scientific contributions (first paper of this special issue).
The X-TOP conferences are now a well-established scientific exchange opportunity for the community concerned. More than 170 participants coming from 21 countries attended X-TOP 2002 (Grenoble-Aussois). An original feature of this meeting were the four `basic' courses on (1) high resolution diffraction (2) grazing incidence diffraction (3) x-ray imaging techniques (absorption, phase contrast, Bragg diffraction) and (4) standing waves, which initiated the conference. Their aim was to give all participants (and more particularly the youngest) the background required to take full advantage of the scientific contributions using the various diffraction and imaging techniques which are used by this scientific community. These basic courses were followed by 40 oral contributions (invited reviews or original contributions) and more than 100 posters. The general scientific and presentation standard of these contributions was very high, and very lively discussions followed most of the talks, or were held in front of the posters.
A special issue of Journal of Physics D: Applied Physics has been published after each X-TOP meeting. The present one is, in the tradition of the X-TOP conferences, not the `Conference Proceedings': it only includes high-level original contributions and invited review papers. The refereeing process has maintained the same standard as for regular contributions to this journal. The rejection rate (not far from 30%) indicates our clear will to retain only the best scientific quality contributions.
The conference covered a wide range of topics such as:
New developments in methods and instrumentation (imaging and diffraction methods, mainly using synchrotron radiation, x-ray optics with special emphasis on the microfocusing and magnifying devices, data recording and processing)
Applications to physical studies (defects, deformation, phase transitions, etc)
Characterization of interesting materials (bulk crystals including biological crystals, layers and super-lattices, nanostructures, quantum dots)
Theoretical aspects such as the predictions of dynamical theory when using ultrashort pulses (new x-ray sources) or how valid usual approximations of this theory are when considering the new, layered or nanostructured, materials.
Most of these topics can be found in the contributions to the current issue. While there is of course considerable overlap, these contributions have been grouped into four main areas: (1) diffraction theory and techniques (2) x-ray imaging and coherence (3) high angle, high resolution, diffraction and (4) grazing incidence diffraction and reflectivity.
I would like to thank Claudine Brun and Myriam Dhez for the outstanding work they performed organizing the conference and the administration of the refereeing process. I would also like to thank the 130 referees for their cooperation. In many cases, their work led to a significant improvement of these papers.