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. 38           October 17, 1995

Table of Contents


    1. OPERATIONS UPDATE -- ALS TO MOVE TO FULL-TIME OPERATIONS
    2. DIAGNOSTIC FLEX BAND TO MONITOR HEAT AND RF FIELDS
    3. SPEAKERS FOR ALS USERS' ASSOCIATION ANNUAL MEETING
    4. TIMING WORKSHOP TO FOLLOW USERS' MEETING
    5. OPEN HOUSE COMING OCTOBER 28

1. OPERATIONS UPDATE -- ALS TO MOVE TO FULL-TIME OPERATIONS
(contact: rmmiller@lbl.gov)

On November 1, user operations are scheduled to resume from the current shutdown for major installations and maintenance. The new operating schedule calls for a full 21 shifts per week, rather than the pre-shutdown 14 shifts per week. User beamtime will occupy 15 shifts per week, an increase of 67% from pre-shutdown levels. User shifts in most weeks will begin on Wednesday at 8:00 a.m. and run until the following Monday at 8:00 a.m.

The first week of user operations (November 1 - 6) will be 1.5-GeV, 320-bunch, 400-mA.

Weekly operations scheduling meetings will resume on Friday, October 27, at 3:30 p.m. in the Building 6 conference room.

2. DIAGNOSTIC FLEX BAND TO MONITOR HEAT AND RF FIELDS
(contact: g_krebs@lbl.gov)

One of the final activities of the current ALS shutdown will be the placement of a special diagnostic flex band/vacuum bellows assembly at the upstream end of the sector 2 straight. This is the position in which a flex band failed this spring, causing a 17-day outage (see ALSNews Vol. 26, May 23, 1995). The new diagnostic assembly will monitor temperatures and radio-frequency (rf) fields in the flex band.

A vacuum bellows is an accordion-like device that forms a flexible joint between sections of the storage ring. When the ring is heated to drive off contaminants, the bellows accommodates the resulting thermal expansion. Flex bands were created to provide a smooth, electrically conductive lining for each bellows that could also flex. A flex band resembles the slightly bent fingers of a pair of hands placed palm to palm. The beam travels between the two hands, parallel to the fingers. Without the smoothness of the flex band, the rf fields in the bellows would be distorted by the accordion shape, causing a buildup of electric charge and generating heat.

The new diagnostic bellows has four ports, three of which will be put to use immediately. The top of the device is fitted with a zinc selenide infrared window and an infrared camera, which will generate images to show hot spots inside the flex band. Two rf ports, one on the side of the bellows and one on the bottom, monitor the electric and magnetic components of the rf fields within. The remaining side port is designed to hold thermocouples if they are deemed necessary in the future.

Last May, the flex band in the position now under observation was found to have one broken finger that bent down into the center of the vacuum chamber, blocking the normal electron orbit. As part of the current shutdown, other flex bands were examined for signs of related trouble; all those examined were given a clean bill of health. One potential explanation for the failure is that it was related to the unique position of the flex band: there are two types of flex bands in the ALS, and this one is the first of its type that electrons entering the storage ring encounter. Keeping tabs on this particular flex band may therefore be critical in determining the cause of the failure.

The diagnostic flex band/bellows assembly was designed and produced by ALS accelerator physicists and engineers.

3. SPEAKERS FOR ALS USERS' ASSOCIATION ANNUAL MEETING
(contact: alsuser@lbl.gov)

The ALS Users' Association Annual Meeting will convene on October 23 and 24, giving the synchrotron community an opportunity to hear about research results and other highlights from the ALS. Here is the program of speakers for the meeting:

Monday, October 23
    08:30   Welcome (C. Shank, Director, LBNL)
    08:45   Panel on Scientific Funding (W. Oosterhuis, DOE; 
            T. Weber, NSF; M. Lubell, CCNY & APS)
    10:45   Report on ALS (B. Kincaid, Director, ALS)
    14:00   ESCA Microscopy Beamline at ELETTRA (M. Kiskinova, Trieste)
    14:30   Measuring Wavefront Aberrations in Soft X-Ray Optics Using 
            At-Wavelength Interferometry (J. Bokor, LBNL)
    15:00   Marching to a Different Drummer: Beamline 6.3.2 at the ALS 
            (J. Underwood, LBNL)
    16:00   First Results from Chemical Dynamics Beamline 9.0.2 
            (A. Suits, LBNL)
    16:30   Recent Advances in Gas Phase Spectroscopy on Beamline 9.0.1
            (N. Berrah, W. Michigan U.)
    17:00   X-Ray Atomic and Molecular Spectroscopy (D. Lindle, 
            U. of Nevada)
    
Tuesday, October 24
    08:30   High-Resolution Photoelectron Diffraction at Beamline 7.0 
            in Metals (J. Denlinger, U. of Wisconsin-Milwaukee) 
            and Silicon (E. Rotenberg, U. of Oregon)
    09:00   Materials Physics on Beamline 8.0 at the ALS 
            (J. Carlisle, LLNL)
    09:30   Local Probing of the Surface Chemical Bond in Adsorbates in
            Metal Interfaces Using Core-Level Spectroscopy (A. Nilsson,
            Uppsala U.)
    10:30   Spectromicroscopy at the ALS (T. Warwick, LBNL)
    11:00   X-Ray Microscopy at Beamline 6.1: Performance and 
            Applications (W. Meyer-Ilse, LBNL)

4. TIMING WORKSHOP TO FOLLOW USERS' MEETING

On Wednesday, October 25, from 8:00 a.m. to 12:00 p.m., there will be a workshop at the ALS on timing experiments. Timing methods rely on measuring the time lapse between the initiation of an event (often by a synchrotron pulse) and the detection of subsequent events (such as the emission of electrons from excited atoms). Common timing measurements include time-of-flight spectroscopy, lifetime measurements, and some coincidence measurements. Existing techniques involving few-bunch operation will be discussed, as will possible alternative methods involving higher storage-ring currents and therefore greater compatibility with other experiments requiring intense beams.

If you are interested in attending the workshop, please contact Elizabeth Saucier (alsuser@lbl.gov or 510-486-6166). For technical information about the workshop, please contact Fred Schlachter (fred_schlachter@lbl.gov or 510-486-4892).

5. OPEN HOUSE COMING OCTOBER 28

Scientists, engineers, and other staff all over Lawrence Berkeley National Laboratory are poised to show off their work to the public on Saturday, October 28 from 10:00 a.m. to 3:00 p.m. Here's a partial listing of the many activities scheduled for the day:

Welcome Tent and Central Exhibits (near Building 50)
    General information, food, entertainment, overview of Laboratory 
      activities.

Open Facilities
    The ALS (of course!)
    National Center for Electron Microscopy -- sit down at the controls
      of the national's most powerful microscope.
    88-Inch Cyclotron -- tour the world's most productive user facility 
      for low-energy nuclear physics.
    Bevatron -- take a look at the "atom smasher" where three Nobel 
      prizes were won.
    Advanced Engineering Technology (Buildings 25 and 77) -- tour 
      engineering shops and assembly areas.

Featured Speakers (Building 50 Auditorium)
    10:30  "Re-creating the Early Universe in the Laboratory" (Jay Marx)
    11:15  "Shedding New Light on the Fight Against Breast Cancer"
           (Mina J. Bissell)
    12:00  "From Drugs to Materials: A Library Approach" 
           (Peter G. Schultz)
    12:45  "How Do You See a Quark?" (Robert N. Cahn)
     1:30  "From FDR to Bush: Fifty Years Advising the Presidents"
           (Glenn T. Seaborg)
     2:15  "Neutrino Astronomy: Studying the Stars from a Mile 
           Underground" (Eric B. Norman)

Science Discovery Theater (Building 62): shows for kids of all ages presented by the Lawrence Hall of Science
    10:20  "Quakes and Shakes"
    12:15  "Be a Brainiac Dude"
     2:00  "Flames, Flares, and Explosions"

Family Science Tent (near Building 50): Learn how to make Water Drop Mazes, how to build Marble Raceways, and more. For school age
children and their parents.

If you are not currently subscribing to ALSNews and wish to receive it by electronic mail, send your internet address to ALSNews@lbl.gov. We welcome suggestions for topics and content. Writers: deborah_dixon@macmail.lbl.gov, jccross@lbl.gov, annette_greiner@lbl.gov