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SSRL Headlines Vol. 2, No. 7  January, 2002

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Contents of This Issue:

  1. Science Highlight - Bacterial Sulfur Storage Globules
  2. Delegation from Catalonia Visits SSRL
  3. SSRL Users' Organization Executive Committee Update
  4. A Decade of Dedication
  5. Beam Line 2 Vacuum Leak Follow-up
  6. SSRL in the News
  7. Upcoming Events at SSRL and Elsewhere
  8. User Research Administration Announcements

1.  Science Highlight - Bacterial Sulfur Storage Globules
    (contacts: Ingrid Pickering, pickering@ssrl.slac.stanford.edu, Graham George, george@ssrl.slac.stanford.edu)

Sulfur is essential for all life, but it plays a particularly central role in the metabolism of many anaerobic microorganisms. Prominent among these are the sulfide-oxidizing bacteria that oxidize sulfide to sulfate. Many of these organisms can store elemental sulfur in "globules" for use when food is in short supply. The chemical nature of the sulfur in these globules has been an enigma since they were first described as far back as 1887; all known forms (or allotropes) of elemental sulfur are solid at room temperature, but globule sulfur has been described as "liquid", and it apparently has a low density - 1.3 compared to 2.1 for the common yellow allotrope alpha-sulfur. Various exotic forms of sulfur have been proposed to explain these properties, including micelles (small bubble-like structures) formed from long-chain polythionates, but all of these deductions have been based upon indirect evidence (for example, the density was estimated by flotation of intact cells), and many questions remained. Using X-ray absorption spectroscopy at the sulfur K-edge recorded on SSRL's Beam Line 6-2, Ingrid Pickering, Graham George and Eileen Yu (SSRL) together with co-workers from Arizona State University, University of British Columbia, and ExxonMobil Research and Engineering Co. have resolved this long-standing conundrum and the results are described in a recent publication.

More information regarding this research, including the reference to the publication in Biochemistry can be found at:
http://www-ssrl.slac.stanford.edu/research/highlights_archive/sulfur.html


2.  Delegation from Catalonia Visits SSRL
     (contact: Katharina Baur, baur@ssrl.slac.stanford.edu)

In conjunction with a visit to Stanford University and discussions with Stanford President John Hennessy on January 17, 2002, Catalonian President Jordi Pujol visited SSRL to gain a better insight into the broad range of scientific research conducted at a synchrotron radiation facility. Following an overview presentation given by SSRL Deputy Director Jo Stöhr, President Pujol was given a tour of the SSRL experimental hall. At BL9-2, staff scientist Ana Gonzales described how high energy x-rays are used in the determination of 3-D protein structures. Katharina Baur then introduced him to a research effort currently underway on BL6-2 involving trace impurity analysis on semiconductor surfaces and its importance to the semiconductor industry. Other delegates joining the tour included, Pujol's Deputy Minister of Education, Ramon Farre; Minister of Industry and Commerce, Antoni Subira; Minister of Universities, Technology and R&D, Andreu Mas-Colell and Science Advisor and Physics Professor Ramon Pascual. Relevant to plans for construction of a Catalonian synchrotron facility by 2006, the group learned that SSRL attracts scientists from more than 200 institutions and has become a nucleus for national and international collaborations involving pharmaceutical design, environmental monitoring and detection of impurities in high-tech materials - among many others.


3.   SSRL Users' Organization Executive Committee Update
    (contact: Corwin Booth, SSRLUO-EC Chair, chbooth@lbl.gov)

As users should be aware, plans and preparations for SPEAR3 have been underway at SSRL for several years. Users will not have access to SSRL beam lines during the installation and commissioning of this third generation light source, which is scheduled from approximately April 2003 through January 2004. A subcommittee of the SSRL Users' Organization has been formed to represent users' issues related to the shutdown and to suggest ways that SSRL may be able to mitigate the resulting loss of beam time to users. The subcommittee members include Uwe Bergmann, Corwin Booth, Paul Foster, Lipika Basumallick, Ben Bostic, Nicholas Pingatore and Vittal Yachandra.

The SSRL Users' Organization Executive Committee has scheduled their next meeting on Friday, March 15, from 10:30 a.m.-12:30 p.m. The meeting will be held in the Orange Conference Room, which is located in the SLAC Central Lab Building 40 (adjacent to the SLAC cafeteria). The agenda includes a SPEAR3 update as well as a presentation on beam line development. All interested SSRL users are invited and encouraged to attend. If there are other issues that users would like to bring to the attention of the Users' Organization, please feel free to contact anyone on the Executive Committee. A listing of the SSRLUO-EC members, agenda and site map can be found at:
http://www-ssrl.slac.stanford.edu/users/ssrluo/ssrluoec-mtgs.html


4.  A Decade of Dedication

Despite a forward-looking focus on SPEAR3 and future developments such as the Linac Coherent Light Source (LCLS), we want to take this opportunity to mark an important anniversary - it has now been 10 years since the injector synchrotron complex was commissioned and SPEAR became a fully dedicated synchrotron radiation source.

In 1992 we reported that 26 beam line stations served 280 experiments from 130 different principal investigators. In all, 550 experimenters came to SSRL during the experimental run that spanned from February 17 - September 7, 1992. In comparison, during the most recent experimental run ending July 3, 2001, 776 individual experiments were scheduled across 32 beam line stations and approximately 900 users came to the facility to run these experiments. The dedicated injector, with its reliable operation and "on demand" injection was one of the main underpinning factors in vastly improving SPEAR beam time delivery and performance that contributed to this strong growth. We thank both the staff who managed the project so efficiently and the DOE Office of Basic Energy Sciences for providing the funding.

Non-coincidentally, several SSRL staff members, including Dave Calloway, Ian Evans, Chris Hoover, Craig Haggart, Thomas Nguyen and Howard Page, were recently honored at a SLAC Service Awards program for employees who had completed 10 years of service during 2001. Jonathan Dorfan, SLAC Director, congratulated the honorees for their contributions and presented each with a service pin and a gift. While 10 years of service for these individuals or any other SSRL staffers cannot be easily summed up, we do know that Ian, SSRL's Safety Officer, has reviewed upwards of 5,290 experiments for safety concerns during his tenure, and Dave, Chris, Craig, Thomas and Howard, members of the behind-the-scenes Accelerator Operations group responsible for keeping beam in SPEAR, have steered a lot of beam and logged in thousands of shift reports.


5.  Beam Line 2 Vacuum Leak Follow-up
    (contact: Hal Tompkins, tompkins@ssrl.slac.stanford.edu)

The last two weeks of 2001 were marked by the closure of Beam Line 2 for vacuum reasons. During the December 10-11 Accelerator Physics period the BL2 moveable mask was being cycled normally when a leak in the bellows that allows the vertical motion of this water-cooled copper mask occurred. The initial indications were that BL2 tripped closed on a vacuum fault with a subsequent SPEAR vacuum fault. Vacuum personnel immediately mobilized and the Accelerator Physics program was terminated to find the source of the leak. It was at this time that the leak was isolated to the BL2 mask bellows. A temporary repair was effected by spraying the bellows with a vacuum sealant. Since further cycling of the bellows would almost certainly have reopened the leak and vented SPEAR, the decision was made to leave the beam line closed until more permanent repairs could be made.

Minimizing the impact on users on other lines and bringing BL2 back up as soon as possible required that we be in a position to replace the bellows at the beginning of the 2001 Holiday shutdown, basically giving the lab two weeks to prepare. This would allow the Holiday shutdown period to be used for pumping the quadrant of SPEAR that had to be vented. Building a new mask in two weeks time seemed out of the question so we removed an unused mask from Beam Line 7 and modified it to fit Beam Line 2. The Accelerator Department managed to finish preparations with two days to spare and the beam was shut down early on Friday, December 21, for installation. Since this is a part of the Machine and Personnel Protection Systems (PPS), SSRL staff were required to come in between Christmas and New Year's Day to certify proper operation of the mask. BL2 was then opened for operation on January 2 along with all the other beam lines. Initial lifetimes were degraded but the normal lifetimes were recovered after the first 24 hours of operation with beam.


6.  SSRL in the News

As we find news highlights that involve research done at SSRL or other items, we will provide links (or citations if not available on line) in SSRL HEADLINES where we feel that these articles will be of interest to the SSRL community, our users or our sponsoring agencies. Please let us know if you become aware of any "news" that can be highlighted in this section.


7. Upcoming Events at SSRL and Elsewhere

8.  User Research Administration Announcements
   (contacts: Cathy Knotts, knotts@slac.stanford.edu, Lisa Dunn, lisa@slac.stanford.edu)

  • X-ray/VUV Scheduling:

    Beam time request form(s) for active X-ray/VUV proposals for the third scheduling period of the FY2002 experimental run at SSRL have been mailed out. These need to be returned by Wednesday, February 27, 2002 to request beam time for the period covering May 1 - July 7, 2002. Beam time requests can be submitted by fax at 650-926-3600 (to the attention of Daphne Mitchell) or electronically via our website:

    http://www-ssrl.slac.stanford.edu/users/user_admin/xray_btrf.html   (for X-ray lines)

    http://www-ssrl.slac.stanford.edu/users/user_admin/vuv_btrf.html   (for VUV lines)

    The submittal date of February 27th was set to accommodate spokespersons who submitted proposals for the November 1, 2001 deadline and are awaiting their ratings from the Proposal Review Panel (the PRP will meet on February 1-2, so we expect to have the completed ratings distributed to spokespersons by mid February). If you have not received your new rating by this time, please contact Michelle Steger (650-926-3011; steger@slac.stanford.edu).



  • Macromolecular Crystallography Scheduling:

    Beam Time Requests for the March-May 2002 scheduling period are being processed and the schedule will be finalized after proposals and extensions submitted for the December 1, 2001 deadline have been reviewed.



  • Good News and Bad News About SSRL Parking:

    In a continuing effort to better meet the needs of our users, SSRL has designated a parking spot near the entrance of Building 120 for users to drop off/pick up equipment. As the new sign reads, this parking spot has a 30-minute maximum. This spot will be monitored to ensure that it is being used accordingly. SSRL construction activities should conclude at the end of April, so finding a parking spot close to the building may continue to be a challenge for awhile; but on the positive side, most of the parking lot should be returned to SSRL users and staff in early May.

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/

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Last Updated: 23 JAN 2002
Content Owner: L. Dunn
Page Editor: L. Dunn