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Last Updated: | 25 NOV 2002 |
| Content Owner: | L. Dunn | |
| Page Editor: | L. Dunn |
**** **** **** * * * * * * **** **** **** * * * * * * **** **** * * **** HEADLINES - a digital monthly publication
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Contents of This Issue:
1. Science Highlight -Towards the Chemically
Specific Structure of Amorphous Materials:
Anomalous X-ray Scattering from a
Molybdenum-Germanium Alloy
(contacts: Hope Ishii, Sean Brennan, and Arthur Bienenstock)
In a significant advance in the field of structural studies of amorphous materials, researchers at SSRL have used Anomalous X-ray Scattering to derive the three partial pair distribution functions (PPDFs) of a binary alloy. Both Differential Anomalous X-ray Scattering and X-ray Absorption Spectroscopy can be used to determine the average surrounding of each species in an amorphous solid, but distinguishing which atomic species are at which distances can be difficult in many cases. With this new approach, individual a-a, b-b and a-a PPDFs are determined. With the added advantage of increased sensitivity to next-near- neighbor distances and coordination numbers, this advance will result in a greater understanding of the atomic arrangements in amorphous materials.
More information regarding this research can be found on the SSRL Home Page and clicking on the Nov 2002 Science Highlight link. Please see the SSRL Science Highlights page for an archive of previous highlights.
2. U.S. Secretary of Energy Spencer Abraham
Visits
SLAC
(contact: Tom
Mead)
On Monday, November 25, 2002, Spencer Abraham, U.S. Secretary of Energy, visited the Stanford Linear Accelerator Center (SLAC). He was accompanied by Dr. Raymond Orbach, Director of the Department of Energy's Office of Science.
Secretary Abraham opened his remarks by saying, "I often refer to our national laboratories as America's crown jewels - national assets that make a priceless contribution to our national security and to scientific knowledge." Following his presentation, Secretary Abraham toured the SLAC site, visiting the linear collider, the Next Linear Collider test area, the massive BABAR detector, and a structural biology experimental station at the Stanford Synchrotron Radiation Laboratory, which proved to be of special interest to the Secretary. This station, outfitted with cutting edge automation, which allows for optimized usage of the resource, has enabled the determination of the molecular structure of the anthrax lethal factor complexed to its natural biological substrate. This structure, displayed in three-dimensional graphics for the Secretary, represents a critical step towards creating effective therapeutic agents to combat anthrax infection.
The Secretary was delighted by his tour of the SLAC site and spoke of his idea to deliver a major policy speech stressing the importance of fundamental science research and the practical consequences of such research to the nations' economic health and security.
3. Critical Decision 1 Approval Moves LCLS Project
Forward
(contact: John Galayda)
On October 16 2002, the Linac Coherent Light Source (LCLS) Project received approval of Critical Decision 1 from the Office of Science of the Department of Energy. With CD-1, SLAC is authorized to carry out the engineering design of the facility, for which a total of $33.5M have been requested. The first allocation of design funds, $6M in FY2003, were submitted to Congress in the President's Budget and approved by both the House and Senate Appropriations Committees.
Critical Decision 1 is also termed "approval of preliminary baseline range" by DOE. This means that, for budget planning purposes, DOE has accepted an estimate of $200M-$240M for the construction cost of the LCLS. This estimate is based on a conceptual design and comprehensive cost data that were presented during the April 2002 DOE Review of the LCLS. In 2004, this "range" will be replaced by a firm definition of schedule, scope and cost of the LCLS; DOE approval of this definition will constitute Critical Decision 2. The LCLS Project Collaboration (SLAC, LLNL and ANL) has proposed to begin long-lead procurements such as the undulator in FY2005. Civil construction will begin in 2006 and the Project is scheduled for completion at the end of 2008.
Critical Decision 1 and the first allocation of engineering design funds mark the debut of the LCLS Project in Congress and the transition from R&D to project activity.
See also "Battle to Become the Next-Generation X-ray Source" in the November 15, 2002 issue of Science for more information on X-ray FELs including the LCLS.
4. SLAC-DESY MOU
(contact: Jerry Hastings)
On November 1, 2002 the directors of SLAC and the Deutsches Elektronen-Synchrotron DESY signed a Memorandum of Understanding (MoU) "Establishing a collaborative research effort to enable the exploitation and expansion of the scientific capabilities of the Linac Coherent Light Source and the TESLA X-Ray Free-electron Laser". This MoU sets the framework for a collaboration that will have broad impact on the science and technology of Free Electron Lasers in the X-ray regime and on the scientific utilization of these unique new light sources. Within the framework, activities of collaboration are identified by annexes to the MoU and the first of these was also signed by the partners in Washington. The initial efforts in this collaboration will focus on the commissioning and use of the Sub Picosecond Photon Source (SPPS) which will become available in May 2003. The SPPS is a spontaneous radiation (undulator) source that will use an 80 fs, 28 GeV electron bunch produced in the SLAC Linac to produce 8 keV photons. The collaboration activities in the first running time will focus on commissioning of the radiation source and beam line, verifying the photon beam performance and establishing the tools to permit optical laser pump-x-ray probe experiments that should give new insights into non-equilibrium dynamics in condensed systems of interest in chemistry and materials research.
5. Amped Up and Ready to Go!
(contact: Max Cornacchia)
Accelerator operations resumed for users as scheduled on November 11. The beam current is the normal 100 mA, its lifetime is improving rapidly and the orbit stability is good. It is noteworthy the large amount of SPEAR3 work carried out during the shut-down did not hinder the scheduled start of operation.
There was some concern at first when it was observed that an instability appeared to limit the amount of current that could be stored to about 20 mA. This phenomenon required a considerable amount of investigation, and several experts converged to SPEAR to help solve the problem. The SSRL team is grateful to the Power Conversion, Klystron, Accelerator and Site Engineering and Maintenance Departments of the Technical Division for their assistance in diagnosing and suppressing the instability. It appears that the problem was caused by a mismatch of the radio-frequency waveguide to the klystron and it was solved by removing a section of the waveguide by the appropriate length. There are several speculations as to why this instability was not visible in previous runs. A possible explanation is that a second cavity and klystron that were taken out of SPEAR during the shutdown in preparation for SPEAR3 changed the damping of the accelerator.
See SPEAR Status page for current updates on SPEAR operations.
6. New Management Structure in the Macromolecular
Crystallography Group
(contact: Britt Hedman)
A recent reorganization has occurred in the Macromolecular Crystallography subgroup in the Structural Molecular Biology program. Leadership of the general user, operational and a number of R&D activities of the group, formally provided jointly by Drs. Peter Kuhn and Mike Soltis, will now reside solely with Mike Soltis. The core leadership for the specific activity in structural genomics (the Structure Determination Core of the Joint Center for Structural Genomics), which was formally led by Peter Kuhn, will now be jointly assumed by Drs. Linda Brinen and Ashley Deacon. These changes come about with the very recent departure of Peter Kuhn who has taken a new position at The Scripps Research Institute. SSRL is extremely fortunate to have a group of talented scientists who can assume an increased leadership and management role. Mike Soltis has for many years stewarded the development of many aspects of SSRL's very successful macromolecular crystallography program. Linda Brinen and Ashley Deacon have been key players in SSRL's part of the JCSG effort to develop a high throughput, automated structure determination pipeline. Looking to the future, these three scientists have indicated their strong desire and intention to work closely together, as well as with those who are in their respective subgroups, to maximize the productivity, effectiveness and user service and productivity of the macromolecular crystallography resources at SSRL.
7. User Research Administration Announcements
(contacts: Cathy Knotts and
Lisa Dunn)
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SSRL Headlines is published electronically monthly to inform SSRL users, sponsors and other interested people about happenings at SSRL. SSRL is a national synchrotron user facility operated by Stanford University for the U.S. Department of Energy Office of Basic Energy Sciences. Additional support for the structural biology program is provided by the DOE Office of Biological and Environmental Research, the NIH National Center for Research Resources and the NIH Institute for General Medical S ciences. Additional information about SSRL and its operation and schedules is available from the SSRL WWW site.
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