 |
Last Updated: | 23 JAN 2002 |
| Content Owner: | L. Dunn | |
| Page Editor: | L. Dunn |
**** **** **** * * * * * * **** **** **** * * * * * * **** **** * * **** HEADLINES - a digital monthly publication
____________________________________________________________________________
1. Science Highlight - Solving a Forefront
Problem in Materials Science: The Magnetic and Chemical Structure of a
Buried Interface
(contacts: Hendrik Ohldag,
ohldag@ssrl.slac.stanford.edu,
Jan Lüning, luning@ssrl.slac.stanford.edu,
Jo Stöhr, stohr@ssrl.slac.stanford.edu)
Computer hard drives and other advanced electronic devices depend on layered stacks of magnetic and non-magnetic materials, but researchers don't fully understand why such layered materials exhibit new properties that cannot be predicted from the properties of the individual layers. In a recent publication, a team working at SSRL and the ALS describes new methods, based on x-ray spectroscopy and x-ray microscopy that reveal the magnetic structures at the boundaries between these layers. Their data show that the boundaries are not as clean as previously assumed but a new ultrathin interface layer may be formed by a chemical reaction. The thickness of the interfacial layer is found to change with temperature and this change can be directly correlated with the magnetic properties of the multilayer stack. The work provides the first magnetic images of a buried interface and gives direct experimental evidence for the existence and long-assumed importance of interfacial magnetic spins.
More information regarding this research, including the reference to the recent publication in Physical Review Letters and other reviews, can be found at: http://www-ssrl.slac.stanford.edu/research/highlights_archive/buried_interface.html
2. Holiday Greetings from the SSRL
Director
Dear Users, Colleagues and Friends of SSRL - as we near the end of 2001, I would like to take a moment to reflect back on the past year.
We are most pleased that we have been able to serve you, the users, to enable breakthrough science in many areas, from materials and physics to biology to research in environmental remediation and areas important to the security of our nation. With your help, we have highlighted examples of this science each month in the SSRL on-line newsletter and look forward to continuing to do so in the coming year. We are making great progress on the SPEAR3 upgrade (see the article later in this newsletter) and the project remains on track for an installation in 2003. Following commissioning, we will be able to deliver to you beams with much higher brightness and intensity to provide the opportunity for new science. In the meantime, we continue to make improvements on existing beam lines. In the longer term, plans for the X-ray FEL (LCLS) are progressing well and we, as well as several other efforts around the world, have done experiments that demonstrate SASE at longer wavelengths and give confidence that the goals of X-ray SASE are achievable. When operational, hopefully in late 2006, LCLS will provide remarkable new opportunities for discovery. It has been a busy year in many other ways - hosting visits by the Stanford Faculty Senate and Board of Trustees, DOE Under Secretary Card, several delegations from other light sources, the Welch Foundation, and others. We have continued to work closely with our colleagues at ALS to find the best means to serve the global synchrotron needs of the user community and jointly sponsored a Stanford-Berkeley summer school which was a real success and which we will repeat in the future.
I would like to thank those who serve on our advisory committees - the Proposal Review Panel, the SLAC Science Policy Committee, the SSRL Users' Organization Executive Committee, the SMB Advisory Committee and the LCLS SAC and TAC for their tireless work and advice. Guidance from these groups is extremely important to help us plan and move forward in the wisest and most effective ways. We continue to be grateful to our funding agencies - the Department of Energy Office of Basic Energy Sciences for providing the core operations funding and support for materials research and the DOE Office of Biological and Environmental Research and the National Institutes of Health NIGMS and NCRR Programs for support of the structural biology program. Without their effective support, we would not be able to push the technological forefront and serve such a large and growing user community.
Lastly, we say this a lot, but cannot emphasize it enough - please let us know your opinions and ideas - it helps us serve you better and improve our operations. In closing, let me extend our very best wishes to all of you for the holiday season and for a great 2002!
- Keith Hodgson, SSRL Director
3. SLAC Science Policy Committee
Meets
(contact: Keith Hodgson,
hodgson@ssrl.slac.stanford.edu)
The SLAC Science Policy Committee (SPC) held its second meeting of
the year on Dec. 7-8, 2001. The SPC is SLAC's highest level
oversight committee and reports to the President of Stanford
University on both the high energy and synchrotron science activities
of the lab. The synchrotron science focus at this meeting was a
series of presentations and discussions in two main areas - the LCLS
and the short pulse photon source experiment (SPPS) and the materials
science program and future plans. Copies of the SSRL presentations
can be downloaded in powerpoint format from the web at:
http://www-ssrl.slac.stanford.edu/spc
The 5-year development plan for the SSRL faculty was also presented. The SSRL presentations ended with a spectacular talk by Z.-X. Shen on his recent work on correlated materials and high Tc superconductivity. The SPC was especially pleased with the more effective coordination between campus and SLAC (in the materials area as well as in structural biology) and noted the very important commitment of the University to build the new user guest lodging (for which ground breaking will happen within a month or two). There was significant discussion of the LCLS program and the SPPS and they strongly endorsed taking advantage of the opportunity for the SPPS experiment. The full report will not be available until the new year, but overall the outcome was very positive for SSRL.
4. Technical Advisory Committee Praises LCLS
R&D
Effort
(contact: John Galayda, galayda@slac.stanford.edu)
The LCLS Technical Advisory Committee met on Dec. 10-11 to review R&D progress since the last review in January 2001. Since that time the makeup of the committee has changed; Dave Attwood of LBNL has stepped down, and Joerg Rossbach of DESY is a new member. Joerg brings an important perspective to the committee, since he has been deeply involved in the design of TESLA and in operation of the TESLA Test Facility free electron laser.
The review emphasized progress in understanding the experimental results obtained from the Gun Test Facility, as well as theoretical and experimental investigations of coherent synchrotron radiation and its deleterious effects on the quality of the LCLS beam. The committee was impressed with, and indeed excited by, the work presented by the LCLS team. They applauded the success of the VISA experiment and the progress in start-to-end simulations of LCLS performance.
The committee recommended that the LCLS team devote some effort to determination of the FEL performance characteristics over a wider range of operating conditions. They also recommended that more extensive study of the undulator channel smoothness be done.
This was perhaps the most exciting TAC meeting to date. The LCLS team received high praise for a tremendous amount of progress. We expect the next meeting will take place around August 2002.
Reports on previous TAC meetings can be found at:
http://www-ssrl.slac.stanford.edu/lcls/LCLS_TAC.HTML
5. SPEAR3 Project at the 50% Completion Mark
(contact: Tom Elioff, telioff@slac.stanford.edu)
The SPEAR3 Project is at the 50% completion mark in terms of overall technical progress and associated costs. 85% of the conventional construction at the East and West straight sections (mostly shielding modifications) has been completed during the last two regular shutdown periods with the remainder scheduled for FY2002. This plan is geared to eliminate any schedule impact of this work on the final technical systems installation in FY2003. The fabrication of main magnets (40 dipoles, 102 quadrupoles, and 76 sextupoles) is now complete; the last shipment from IHEP (Beijing) is on the ocean. Only 66 corrector magnets remain to be completed in the next few months. So far all magnets tested at IHEP and SLAC either meet or exceed specifications. A prototype BM2 support raft (there are 54 rafts of 5 different types) was successfully assembled with magnets and vacuum chamber aligned. Assembly of these rafts is underway; the plan calls for four to be assembled per month over the next year. The goal of this pre-assembly and alignment process is to minimize the FY2003 installation time. While the production of the QFC vacuum chambers is nearly complete, the e-beam welder is being programmed for the more complex BM1 chambers. Also higher order mode tests of the injection kicker magnet chamber were completed and once final electrical tests are done production of the kickers will begin. The final design of the bellows module is also near completion. In the Cable Plant area, an installed cable tray system serving the inside the power supply building and extending to the East and West straight section areas was completed on schedule. The work also included a high voltage wireway from the klystron power supply to the klystron building. Most of the various required power supplies for SPEAR3 magnets are on order or with final design specifications nearing completion. The Instrumentation and Controls group is focusing on final specifications of the Computer Controls system and finalizing plans for the BPM processing and timing signal systems. The project team looks forward to significant progress in the coming new year!
6. Surfing USA for 10 Years - the WWW
December 2001 marks the 10th anniversary of the first US WWW site which,
in fact, was located at the Stanford Linear Accelerator Center and
initially used to share SLAC's substantial catalog of online documents
with physicists worldwide (Stanford Campus Reports, 12/12/2001). To
mark this occasion, SLAC hosted a symposium entitled "The Once and
Future Web," on Dec. 3-4. The symposium celebrated the accomplishments
of the past decade and provided a serious look forward at the
technologies and issues spawned by the Web Revolution. More information
on the program, invited speakers, and photos from the event are
available at the following link:
http://www-project.slac.stanford.edu/webanniv/
7. User Research Administration Announcements
(contacts: Cathy Knotts,
knotts@ssrl.slac.stanford.edu,
Lisa Dunn, lisa@ssrl.slac.stanford.edu)
|
8. SSRL Job Opportunities
(contact: Stephanie Carlson, steph@slac.stanford.edu)
SSRL currently has positions available for mechanical, electronic and beam line engineers and technicians. More information is available at the following web site: http://www-ssrl.slac.stanford.edu/jobs.html
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 Sciences. Additional information about SSRL and its operation and schedules is available from the SSRL WWW site: http://www-ssrl.slac.stanford.edu/
To leave the SSRL-HEADLINES distribution, send email as shown below: To: LISTSERV@SSRL.SLAC.STANFORD.EDU Subject: (blank, or anything you like) The message body should read SIGNOFF SSRL-HEADLINES That's all it takes. (If we have an old email address for you that is forwarded to your current address, the system may not recognize who should be unsubscribed. In that case please write to ssrl-headlines-request@ssrl.slac.stanford.edu and we'll try to figure out who you are so that you can be unsubscribed.) If a colleague would like to subscribe to the list, he or she should send To: LISTSERV@SSRL.SLAC.STANFORD.EDU and use the message body SUBSCRIBE SSRL-HEADLINES