Skip to: main navigation | content

SLAC National Accelerator Laboratory

SSRLUO Executive Committee Meeting Minutes

Meeting Notes: July 11, 2005 12 noon - 5 pm

SSRLUO Home | Committee Members | Meeting Schedule | Meeting Minutes | SSRLUO Activism

Previous SSRLUO Minutes


Attendees: Juana Acrivos, Zaven Altounian, Joy Andrews, Linda Brinen, Michael Brzustowicz, Lisa Downward, Lisa Dunn, Jesse Guzman, Britt Hedman, Bob Hettel, Cathy Knotts, Piero Pianetta, Bill Schlotter, Jo Stöhr, Glenn Waychunas.

Safety Update

Ian Evans gave a presentation on safety, including suggestions for both work and home. In reply to a question about the machine shop at SSRL, users were discouraged from using this shop without specific authorization. They can, however, contact SSRL staff or the Duty Operator to find out if someone can help them to get parts machined. Users are encouraged to stay informed and follow policies as they relate to safety and to ask if they have any questions.


SSRL Director's Update

SSRL Director Keith Hodgson reviewed recent organizational changes at SLAC, which now has 2 main scientific programs: Photon Sciences (Keith Hodgson heads this group) and Particle & Particle Astrophysics (Persis Drell heads this group). Photon Sciences encompasses SSRL and ultrafast science which includes the LCLS science program and a program to develop ultrafast scientific instruments. Keith noted that the report from the DOE program review of SSRL which was held in late January had been received; the report was overall very positive and the panel made a few suggestions including the addition of a separate scientific advisory committee, the need for more beam line support staff, and further development of career paths for beam line scientists.

Keith also reported that SPEAR3 achieved a major milestone in June when 500mA was reached for the first time; things are moving along smoothly and as designed. Additional high current tests are planned for the remaining AP days this run (July 18-19), including tests at BL6-2. Further reviews and approvals are needed by Radiation Protection for 500mA operations in SPEAR and later to deliver to beam lines. We anticipate periods of high current running sometime next year.

Top-Off Injection

Bob Hettel summarized the status of SPEAR, including some diurnal changes, movement and noise that has been noted. A medium orbit feedback system now addresses the trestle movement which was distorting signal at 100mA. A group (including Sean Brennan and Andrei Terebilo) has been assembled to investigate stability issues. Users are encouraged to notify the program managers during their 3 pm walk through whenever noise is experienced at the beam lines.

Bob stated the goal as low noise, thermally stable beam to users, working towards the maximum potential which is 500mA. Higher brightness will be advantageous for some experiments, but some beamlines would need to shut down until they are fully upgraded for 500mA operations. We may try to question users in the next call for beam time requests about their preference (or not) for high current (beam time requests will be due in September for the run which resumes Nov. 28th). It is difficult to predict now how this information will be incorporated into the schedule for the next run until more information is known; there will be internal meetings to help flush this out, and we hope to be able to give users a better idea of the next run schedule before the Fall. We want to be capable of reaching 500mA, and it would be easy to reduce intensity if warranted. Results from early high current tests were promising, and the various approvals are ongoing.

Questions were raised about shortening beam time allocations to accommodate more users. Others noted that this was not very likely at SSRL given resources limitations (experiment changeovers are still staff dependent). Also, longer periods of beam time allow more difficult experiments or allow data to be collected at lower concentrations. Group blocks of beam time may be investigated, particularly among crystallographers, where groups running the same type of experiment with the same equipment set up share beam time to maximize available beam time (e.g., over a long weekend).

Bob discussed several fill scenarios for SPEAR3 at 500 mA as well as top-offs at other labs. There are several reasons for pursuing this option, including the potential improvement in the beam stability owing to the more constant power loading on ring and BL optics as well as the performance boost associated with top off. Without top off, there is some concern that 500mA power loading on the BL optics will result in beam focus and monochromator tune drifts. The issue will not likely be decided immediately (other labs took several years to implement), and radiation protection approvals will need to be obtained for both the ring and the individual beam lines. This topic will be discussed again at the users' meeting with a brief presentation during the SSRL reports session on Tuesday, October 18th and an opportunity to discuss in more depth at a workshop on Wednesday, October 19th. SSRL beam line scientists and other users with experience with top off are asked to be liaisons and encouraged to share their experiences with the entire user community; this will help users get a better idea of how and which types of experiments will be impacted with top off.

SPEAR3- A Look into the Future (Including Pulsed Beam for Time Structure)

Jo Stohr presented several slides outlining the present status, vision for the future, and goals for SSRL. Jo described 3 pillars of photon science at SLAC; SPEAR3, LCLS, and Stanford Centers. This model is unique from other labs; the overlap of faculty between Stanford and SLAC/SSRL and interplay of disciplines represents a strong connection and asset. Jo briefly discussed opportunities to use 50-100 ps systems (magnetism, surfaces, etc.). Currently electrons travel in the ring in bunches or buckets. A pulsed beam would allow time resolved studies. User input is requested to consider user interest for pulsed beam and the impact on user experiments of this mode of operation; specifically, what would be the desirable properties for a pulsed beam, how often, what types of experiments would benefit, what is the impact on other types of experiments.

Jo also highlighted the unique role of X-rays over other technologies to better understand structures and how they change with time - the future opportunities are in the world of small and fast.

Piero Pianetta summarized the beam line upgrades and construction activities planned over the summer shutdown which begins on August 1st, including upgrades to BL10, BL9 and BL7. These beam lines will be available for users after upgrades and commissioning are completed. For BL10-1, BL10-2 and BL9-3, this is expected by mid December; BL9-1 and BL9-2 by January 2006. BL7-3 is expected to be available for users by February 2006, with BL7-1 and 7-2 a bit later in early 2006. A preliminary copy of 2006 user operations schedule, which is expected to resume around November 28, 2005 and continue through July 31, 2006, can be found at:

Update of User Activities and Activism

SSLRUOEC Chair Glenn Waychunas shared material prepared and presented by the UEC chairs during the meetings in Washington in April.

3-3:30 pm SSRLUOEC Update

  • UEC chairs/vice chairs trip to DC in April; another meeting potentially in the Fall
  • UEC chairs to meet at SSRL Oct. 17th
  • User activism (encourage visits to representatives; write letters)
3:30-4 pm 32nd Annual SSRL Users' Meeting

  • Feedback requested from the 2004 Annual Users' Conference
  • Preliminary Plans for the 32nd Annual Meeting on Oct. 17-18, 2005; 1st mailing postcard to be distributed shortly; website under development:
  • Possible workshops to date:
    • Biological Small Angle X-Ray Scattering Workshop (H. Tsuruta), Oct. 15-16th (Sat-Sun)
    • Soft X-Ray Science at LCLS Workshop (J. L√ľning, A. Nilsson), Oct. 18-19th
    • Top off injection (B. Hettel) - half day? Pulsed beam?
    • Tentative - Environmental Science Workshop (J. Bargar)
    • Tentative - Materials Small Angle X-Ray Scattering Workshop (M. Toney, J. Pople)
    • Any other suggestions for workshop topics?
4-4:30 pm SSRL/SSRLUOEC Awards (C. Knotts/L. Dunn)

4:30-5 pm Outreach, Communications, User Administration (C. Knotts/L. Dunn)
5-5:30 pm Walk-in Items

The meeting adjourned around 5:30 pm.

Cathy Knotts
SSRL Liaison to SSRL Users' Organization Executive Committee

2575 Sand Hill Road, MS: 99, Menlo Park, California, 94025, USA Tel: 650-926-4000 | Fax: 650-926-4100