This
document is an online publication of the Planning Notes written by
Steve Wilkins, which summarizes the Round Table discussions during the
2nd Australian-Italian Workshop (ICTP, May 2005). Attachment A
has
been contributed by Chris Jacobsen.
General
field of activity
International cooperation and support for research in the area of:
- Coherent
diffractive imaging (CDI)
- All
methods of X-ray phase-contrast imaging and microscopy
- Related
methods of tomography
- Full-field
and related scanning X-ray microscopy (including soft X-ray)
- Related
fundamental physics aspects
- Related
X-ray optics and instrument development such as detectors
- Associated
software development and sharing
- Access
to major imaging facilities via remote access.
Some related
Scientific and Technical Challenges
- Development
and exploitation of appropriate high-brilliance and.high-coherence
sources with appropriate time structure. Includes pulsed X-ray sources
such as laser-powered pulsed X-ray sources, Energy Recovery Linacs
(ERL’s), and X-ray Free-Electron Lasers (XFEL’s).
These can
give pulse lengths in the picosec to 10’s of femtosec range.
- Development
of high-coherence X-ray optics with low speckle. Also require large
numerical apertures and low aberrations for phase-contrast imaging
applications.
- Development
of high DQE, high-total-count-rate photon-counting imaging detectors
with some energy resolving capability, either
- with very
small pixel sizes ( ∼ 1 µm pixel size) and moderate
area or
- large
area photon counting detectors with moderate spatial resolution (say 40
µm) especially regarding implementation of phase-contrast
imaging
for clinical medical and biomedical applications .
- Development
of specialized detectors for very high count rate applications such as
CDI using XFEL’s.
- Development
of robust algorithms for CDI phase retrieval taking into account
missing data (especially near q=0) and low signal-to-noise ratio
inherent in such data (especially at large q).
Guidelines
for Formation and Operation of I<CCXD>I
What the
I<CCXD>I
is not
Not a research organization carrying out research itself. Rather
a coordinator and enabler for research and a conduit for funding of
specific activities (apart from basic infrastructure and some IT and
imaging theory activities).
Aims of
I<CCXD>I
- To foster
international cooperation and understanding in the area of coherent
X-ray diffraction imaging and closely related areas of
research.
- To
especially promote and support opportunities for the involvement of
people from developing countries in remote access to advanced X-ray
imaging techniques and facilities, and especially those relating to
CDI.
- To support
and promote software development, evaluation and
sharing among I<CCD>I consortium members. See
attachment A,
- To
run Conferences, Workshops and Training Courses in areas relating to
CDI.
- To
act as a repository for selected CDI and related image data, especially
for use in testing and evaluating different CDI data inversion methods
.
- To
seek and assist with support for extended study visits at ICTP for
leading established workers and promising young workers in the field of
CDI.
- To
support and pursue funding opportunities in connection with consortium
members who are eligible and wish to combine together on such
proposals.
- To seek to
support research into fundamental aspects of CDI relating to:
- coherence
issues
- methods for
data inversion (phase retrieval)
- methods for
specialized tomography (“zoom”, limited field of
view,...).
- To
gather and post information to members on advanced X-ray detector
developments relevant to CDI. To generate reports on desired
performance characteristics for detectors for CDI. To link with and
provide input to consortia involved in advanced X-ray detector
development relevant to CDI.
- Same as 9.
but for X-ray optics developments.
Actions
and Next Steps
- Form
Interim I<CCXD>I Steering Committee
immediately.
- Identify
and approach additional Members of ICCXDI who
are able to contribute or likely to wish to participate (Interim
Steering Committee).
- Draw up MOU
for signing by Member
organizations. Not signing MOU by organizations does not
prevent
related individuals from joining but may limit their benefits (ICTP and
Interim Steering Committee).
- Seek
contributions from Member’s
organizations (Interim Steering Committee role).
- Explore and
pursue
opportunities for EU and other funding for a Planning Phase for
I<CCXD>I (All).
- Gather
show-case of images related to coherent
diffractive imaging experiments and simulations for use in PR and to
mount on web site.
Attachment
A: On software sharing for CDI (by Chris Jacobsen):
Examples
of community software for “image” reconstruction
Protein
crystallography has been revolutionized!
•
Improved crystallization methods
•
Improved synchrotron beamlines and MAD/SAD data
•
Improved, and
largely standardized, software
It
is now possible for cell biologists with little training in
crystallography to obtain structures from “easy”
crystals
Single-particle
methods in electron microscopy
National Center for Macromolecular Imaging (Baylor University) makes
EMAN available for data processing: Python scripting with C/C++ code
Collaborative effort between Baylor, Wadsworth/Albany, and LBNL/Donner
Lab to develop parallelized software for large data sets. The whole
field will benefit.
We should emulate this approach!
Diffraction
imaging cannot exist without modern computers
•
Iterative algorithms are used to phase the measured diffraction data
and produce a real-space image
•
Computers are also integral to reliable collection of minimum-dose data
throughout a 3D tilt sequence.
Balancing
competition and cooperation
•
We all want to develop new tricks and get credit for our efforts. This
is assuredly good! – competition stimulates creativity.
•
However, once an idea is published, why not make it available? Others
can cite your paper, and benefit from the results (and you can gain by
utilizing a software tool they have developed). “If I have seen
further it is by standing on the shoulders of giants”
– I. Newton.
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