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.