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. 23           May 2, 1995

Table of Contents


    1. STORAGE RING DOWN -- DIAGNOSTIC EFFORTS CONTINUE
    2. OPERATIONS UPDATE
    3. ALS ADMINISTRATION AND ACCELERATOR GROUPS MOVE TO BUILDING 4
    4. ALS USERS' EXECUTIVE COMMITTEE MEETING MAY 26

1. STORAGE RING DOWN -- DIAGNOSTIC EFFORTS CONTINUE
(contact: rmmiller@lbl.gov)

During the swing shift on Tuesday, April 25, while accelerator physicists were performing tests of the longitudinal and transverse damping systems, the stored beam in the ALS storage ring was suddenly lost. Attempts to re-fill the ring were unsuccessful. Since then, ALS staff have been working to restore beam, thus far without success. This is the first time since the ALS was commissioned that a beam outage has persisted for more than a few hours, except for a one-day outage during maintenance and accelerator physics shifts due to an earthquake in June 1994.

Many puzzling features have appeared in the parameters checked so far, but no candidates to explain the new machine behavior have been found. The maintenance period on Monday, May 1 was spent making detailed power supply and magnet measurements and inspections. Since beam accumulation at nominal magnet settings has not been possible, magnet settings are now being systematically investigated. The immediate goal is to establish a closed orbit which will allow the beam to circulate in the storage ring long enough for the electron beam position monitors to measure the horizontal and vertical closed orbit. Closed-orbit measurements are extremely accurate and sensitive to imperfections in magnet placement or current.

There is still no estimate of when user operations will resume. As soon as the problem is diagnosed and corrected, the ALS will return to its scheduled operation, given in #2 below.

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

The storage ring has been down since Tuesday April 25 (see item #1 for details). When operations resume, the ALS will return to the following schedule.

Operations summary for May 2-21
1.5-GeV, 400-mA, 320-bunch operations for users:
    May 2, 08:00-23:15 (formerly accelerator physics shifts)
    May 3, 08:00-16:00 (formerly accelerator physics shift)
    May 10, 08:00-16:00
    May 17, 08:00-16:00
    May 18-21, 08:00-23:15
1.5-GeV, 2-bunch operations for users:
    May 3, 16:00-23:15
    May 4-7, 08:00-23:15
    May 11-14, 08:00-23:15
Maintenance: 
    May 8 & 15, 08:00-16:00, with startup 16:00-23:15
Accelerator Physics:
    May 9 & 16, 08:00-23:15
    May 10 & 17, 16:00-23:15

3. ALS ADMINISTRATION AND ACCELERATOR GROUPS MOVE TO BUILDING 4
(contact: jtkrupnick@lbl.gov)

During the week of May 1-5, ALS management, administration, and accelerator group staff with offices in Building 80 are moving to make way for construction of the ALS Structural Biology Support Facilities. The new office locations are as follows:

    GROUP/PERSON                LOCATION

    ALS User Office             Building 4, Room 102
    ALS Management              Building 4, Second Floor
    Accelerator Physics Group   Building 4, Second Floor
    Fred Schlachter             Building 4, Room 209
      (ALS User Liaison)
    Ray Thatcher                Building 10, Room 113
      (Beamline Operations 
       Section Leader)

Telephone numbers, fax numbers, and mailing addresses will not be affected. The ALS Control Room, Operations Group Leader Bob Miller, and the shops in the basement and first floor of Building 80 will remain in their present locations during the construction, which is scheduled to last approximately one year.

4. ALS USERS' EXECUTIVE COMMITTEE MEETING MAY 26
(contact: tcallcot@utkvx.utk.edu)

The next meeting of the ALS Users' Executive Committee (UEC) is scheduled for May 26, with a primary focus on planning the Annual Meeting of the ALS Users' Association to be held on October 23-24, 1995. The UEC is the official voice of the user community in its interactions with ALS management. Users are invited to express any issues or concerns to a member of the UEC or to Tom Callcott, chair of the UEC (tcallcot@utkvx.utk.edu). The current members of the UEC are listed below.

    Thomas A. Callcott (University of Tennessee), Chair
    Harald Ade (North Carolina State University)
    Nora Berrah (Western Michigan University)
    Jeffrey Bokor (University of California, Berkeley), Vice-Chair
    Norman Edelstein (Lawrence Berkeley Laboratory)
    Marjorie Olmstead (University of Washington)
    Linda S. Powers (Utah State University)
    Eli Rotenberg (University of Oregon)
    Mahesh Samant (IBM Almaden Research Center)
    Louis Terminello (Lawrence Livermore National Laboratory)
    Michael G. White (Brookhaven National Laboratory), Past Chair