New Scientific Opportunities at the European Synchrotron Radiation ...

European Synchrotron Radiation Facility Long-Term Strategy 7 July 2006
Several high performance soft X-ray (E = 2 GeV) SR sources have been operating
for a number of years. Notable amongst these are ALS, ELETTRA and BESSY, all of
which have made very significant scientific advances across a wide range of
disciplines. There have been striking advances in angular resolved photoemission
with parallel detection which has allowed the study of Fermi surfaces in materials
with unprecedented detail and data acquisition rates. The intensity of these soft x-ray
sources, coupled with innovative photon and electron optics, has opened the path to
new, non-destructive, chemical species and magnetic atom selective microscopies,
which in some cases push spatial resolution to the nanometer level. Whilst there is
some overlap with activities at the ESRF, notably in areas of research carried out at
the ID08 soft X-ray beamline, this work is largely complementary to ESRF studies.
At the other end of the X-ray spectrum, that of hard X-rays (say E > 50 keV), the only
European source which can rival the ESRF’s performance will be PETRA-III, to be
operational from 2009 (at which time the DORIS facility may become unavailable).
The small number of beamlines (some 9 have been proposed so far) and the large
demand from the German national community will result in only a minor impact on
ESRF usage.
The most direct impact on the ESRF can be expected from the new medium-energy
sources (SLS, Soleil, Diamond and ALBA). It is however interesting to note that the
start-up of the Swiss Light Source has only led to a slight decrease in usage of the
ESRF by the Swiss SR community; the return coefficient for scientific use remains
close to 1. It is clear that the demand for the ESRF’s protein/macromolecular
crystallography (PX/MX) beamlines for more routine experiments will decline,
especially from the UK biology community as they move to exploit the new Diamond
PX/MX beamlines (three are planned for the initial phase of Diamond’s operation).
However it is reasonable to expect that several years of test and development will be
needed before the Diamond (or Soleil, or ALBA) beamlines can rival those at the
ESRF in terms of reliability, stability and throughput. With less demand for the more
routine projects the ESRF will be able to give more beamtime to the more advanced
biological projects such as protein complexes and membrane proteins that often
require screening thousands of crystals. This procedure has been greatly facilitated
by the automation of the ESRF’s MX beamlines equipped with large detectors.
While Diamond and similar synchrotrons will have very high brilliance for X-ray
energies up to at least 20 keV, a consideration of all factors governing the
experimental signal strength (beamline divergences, apertures, etc) leads to the
conclusion that the cross-over energy where ESRF beamlines become superior is
relatively low, and is calculated to lie below 10 keV.
Where the various free-electron laser projects are concerned, the impact on the
ESRF is expected to be even less direct. The very low energy sources already
operating (e.g. FELIX operates in the infra-red and far-infra-red) provide experimental
facilities for atomic and molecular spectroscopies and have strong programmes in
biological fields (e.g. bio-medicine) in energy regimes far from those of the ESRF.
The field of linear accelerator based FEL facilities is evolving rapidly thanks to
demonstrations of the SASE concept in the visible and VUV region. This progress is
exemplified by the successful operation of the VUV FEL (FLASH) at DESY which is
opening up new and exciting fields of science on ultra-short time scales. The
ambitious soft X-ray and X-ray projects such as FERMI at ELETTRA and the
European X-FEL at DESY are several years away from routine operation. Similar
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