ALSNews is a biweekly electronic newsletter to keep users and other interested parties informed about developments at the Advanced Light Source, a national user facility located at Lawrence Berkeley National Laboratory, University of California. To be placed on the mailing list, send your name and complete internet address to ALSNews@lbl.gov. We welcome suggestions for topics and content.

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ALSNews           Vol. 25           May 16, 1995

Table of Contents


    1. CAUSE OF OUTAGE DISCOVERED -- USER BEAM RESTORED
    2. OPERATIONS UPDATE
    3. CONSTRUCTION BEGINS ON STRUCTURAL BIOLOGY SUPPORT FACILITY
    4. VISITING RESEARCHERS -- JIM PATEL

1. CAUSE OF OUTAGE DISCOVERED -- USER BEAM RESTORED
(contact: ajackson@lbl.gov)

On May 12, after 17 days of systematic searching through all accelerator subsystems, ALS staff discovered the cause of the outage that has stopped ALS operations since April 25. Beam for users was restored the next day, and a definitive correction of the problem is underway. A brief account follows of the sleuthing by ALS accelerator physicists and operators that led to the restoration of beam, and of what they found.

As of the evening of May 9, an orbit had been created in which beam could be accumulated and stored, but the conditions were still far from those routinely applied for users' beam. On the morning of May 12, an accelerator operator found a new orbit with large horizontal steering but otherwise nominal conditions in which beam could be both accumulated and maintained. The shape of this orbit, as measured by the beam position monitors around the ring, suggested that there might be an obstruction in one of the 12 straight sections of the storage ring. The accelerator physics group immediately set out to pinpoint the obstruction, aided by data taken the previous evening that showed distinctive "holes" in the injected beam pattern. They smoothed the new, stable orbit by applying "local bumps" (steering modifications in a single sector using dipole corrector magnets) in one sector at a time, until they found a straight section (straight 2) where the beam lifetime went from 3.5 hours to zero if they moved the beam 2 mm toward the outside of the ring, and increased to about 20 hours if they moved the beam 6 mm to the inside. With further local-bump experimentation they narrowed down the obstruction's location to the upstream end of straight 2.

The obstruction is likely to be a part of one of a pair of "flex bands," devices in the storage ring vacuum chamber that provide a smooth (low-impedance) transition between the different sections of the vacuum chamber and are flexible enough to withstand temperature-induced motion during bakeout. Additional measurements this week should show exactly which part has failed. On May 22, ALS staff plan to remove the damaged part and replace it, using the ALS-developed "dry tent" procedure, in which technicians wearing protective clothing conduct vacuum repairs under a laminar flow of dry, filtered air to prevent contamination of the storage ring vacuum chamber. Beam should be available for accelerator physics and user shifts as scheduled following this one-day repair.

ALSNews will have more information next week on the progress of repairs.

2. OPERATIONS UPDATE
(contact: rmmiller@lbl.gov)

User operations resumed on May 13 at 08:00. See #1 above for details. Maintenance and accelerator physics time for May 15-16 are being devoted to 2-bunch operation for users.

Operations summary for May 16 - June 4
1.5-GeV, 2-bunch operations for users:
    May 16, 08:00-23:15
1.5-GeV, 400-mA, 320-bunch operations for users:
    May 17, 08:00-16:00
    May 18-21, 08:00-23:15
    May 24, 08:00-16:00
    May 25-28, 08:00-23:15
    June 1-4, 08:00-23:15
Maintenance: 
    May 22 & 30, 08:00-16:00, with startup 16:00-23:15
Accelerator Physics:
    May 23 & 31, 08:00-23:15
    May 17 & 24, 16:00-23:15
Holiday
    May 29

3. CONSTRUCTION BEGINS ON STRUCTURAL BIOLOGY SUPPORT FACILITY
(contact: jtkrupnick@lbl.gov)

The "ground-breaking" ceremony marking the beginning of construction for the new Structural Biology Support Facility (SBSF) in Buildings 6 (ALS) and 80 (contiguous with ALS) took place on May 15. Participants in the small ceremony sawed off and signed a ceremonial board rather than turning over a ceremonial shovel full of earth, since the SBSF will be constructed entirely by remodeling existing buildings.

The SBSF, funded at $7.9M, will include laboratory facilities, computers for data reductions and visualization, and office space. Slated to open in October 1996, it will support all structural biology work at the ALS, including research at the protein crystallography beamline scheduled for first experiments in mid-1996.

4. VISITING RESEARCHERS -- JIM PATEL
(contact: patel@ssrl01.slac.stanford.edu)

Jim Patel, an Independent Investigator at the ALS, is here at the invitation of ALS Director Brian Kincaid to find applications in industry for the high-tech capabilities of the ALS.

Patel is retired from a career at Bell Labs and was the spokesperson for the X-Ray Standing Wave Beamline X-15A at the National Synchrotron Light Source (NSLS), so he has first-hand experience with the communication problems between synchrotron light sources and industry. People working in industry are largely unaware of the capabilities of facilities such as ALS, and scientists and engineers at synchrotron facilities often do not know what kinds of problems industries need to solve. Scientists working for private companies are reluctant to risk taking the time away from their institutions that they would need to explore whether a synchrotron facility could help solve a problem.

Finding the industrial problems that match synchrotron facilities' capabilities is Patel's goal. By serving as an intermediary between the ALS and industry, Patel is also addressing the larger problem of how to explain to the public the types of work that take place at national laboratories and why pure scientific research, which can appear unnecessarily esoteric, should be supported. He also sees his work as protecting taxpayers, since early and frequent application of research to industrial problems increases the return on research funding.

Patel will be at the ALS until at least December 1995. He is already working with Intel Corporation as part of his primary commitment to industry, but he also has several research questions he would like to explore. He aims to use x-ray microbeams (beams of micron or sub-micron size, generated using specially shaped capillary tubes) for high-resolution x-ray fluorescence analysis. Microbeam techniques could also enhance high-resolution x-ray powder diffraction studies (in which a crystalline powder can be studied to gain some of the same information available using large, difficult-to-produce single crystals). Patel may also work to develop standing-wave methods for the characterization of materials composed of elements with low atomic numbers. Standing-wave research uses interferometric methods to locate atoms at surfaces, at interfaces, and in bulk materials.