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. 99           April 1, 1998

Table of Contents


    1. CALL FOR INDEPENDENT INVESTIGATOR PROPOSALS - DUE JUNE 1
    2. ALS SCIENTIFIC DIRECTIONS WORKSHOP EXCEEDS EXPECTATIONS
    3. BEAMLINE 9.0.1 CLOSES DOWN WITH SUCCESSFUL ETHENE EXPERIMENT
    4. NEWS FROM MARCH 6 USERS' EXECUTIVE COMMITTEE MEETING
    5. ACTIVITIES FOR APRIL-MAY SHUTDOWN
    6. NEW DATA SHEETS AVAILABLE
    7. WHO'S IN TOWN: A SAMPLING OF ALS USERS
    8. OPERATIONS UPDATE

Note from the editor: This issue of ALSNews is longer than most; sometimes the news comes in all at once. We'll be back to our shorter format as events allow.

1. CALL FOR INDEPENDENT INVESTIGATOR PROPOSALS - DUE JUNE 1

The ALS is now accepting proposals from scientists who wish to conduct research at the facility as independent investigators between October 1998 and March 1999 inclusive. The deadline for proposals is June 1, 1998. There will be no automatic rollover of proposals from the previous proposal cycle (June-September 1998). Scientists wishing to renew a previous proposal should notify the ALS User Administrator, Ruth Pepe (contact information below).

The proposal form for independent investigators is available in Portable Document Format (PDF) on the Web. Information on the proposal process is available at the same location. Data sheets on beamlines at the ALS (see item #6 below) provide information that may be useful to prospective ALS users.

To request a proposal form by mail, contact:
Ruth Pepe, ALS User Administrator
Tel: (510) 486-5268
Fax: (510) 486-4773
Email: alsuser@lbl.gov

For information on beamlines available to independent investigators, contact:
Gary Krebs, ALS User Services Group Leader
Tel: (510) 486-7727
Fax: (510) 486-4102
Email: g_krebs@lbl.gov

2. ALS SCIENTIFIC DIRECTIONS WORKSHOP EXCEEDS EXPECTATIONS
(contact: nvsmith@lbl.gov)

An overflow crowd of more than 300 participants registered for a three-day workshop on Scientific Directions at the Advanced Light Source that was held at the Berkeley Lab from March 23-25 with Yves Petroff, Director-General of the European Synchrotron Radiation Facility, as the chair. The Department of Energy, Berkeley Lab, and the University of California jointly sponsored the workshop in order to formulate a vision for the ALS scientific program into the twenty-first century and to make recommendations that will result in a road map for the implementation of that program.

In her opening presentation to the participants, Patricia Dehmer, Associate Director for Basic Energy Sciences at DOE, emphasized that the intention was to make the ALS the world's premier source of VUV and soft x rays. After the opening plenary session, the bulk of the workshop was spent in breakout groups, where participants were asked to identify the burning issues in their fields, to clarify how the ALS could contribute, and to recommend instrumentation needed to conduct the research.

At the conclusion of the proceedings, Dehmer proclaimed that the workshop had exceeded expectations, but that a number of "products" were now to be forthcoming. One is a report to her that will compile the findings of the breakout groups and lay the groundwork for a new ALS roadmap.

3. BEAMLINE 9.0.1 CLOSES DOWN WITH SUCCESSFUL ETHENE EXPERIMENT
(contacts: jdbozek@lbl.gov, thomast@chem.orst.edu)

For the last three years, Beamlines 9.0.1 and 9.0.2, which serve growing experimental programs in atomic, molecular, and optical physics and in chemical dynamics, have been sharing the beam from the undulator in Sector 9 of the ALS. Now Beamline 9.0.1 is moving to Sector 10, where it will receive all user beam from its undulator. On March 1, Beamline 9.0.1 was decommissioned to begin its move by forklift and crane across the experiment floor. Thanks to speedy work by ALS technical staff, the beamline is nearly complete and under vacuum in its new location. Operations at the new Beamline 10.0.1 are scheduled to begin June 3.

The last year at Beamline 9.0.1 has been a fruitful one. One set of experiments, by T. Darrah Thomas's group from Oregon State University, exploited the high spectral resolution available from this beamline and its electron spectrometer to measure the carbon 1s photoelectron spectrum of core-ionized ethene (CH2=CH2) at the fundamental resolution limits imposed by its natural line widths. The measurements, with a resolution of 55 meV, conform very well to a model of core-ionized ethene in which the core hole vacated by the ejected photoelectron is localized to one carbon or the other.

Molecular physicists are keen to understand the vibrational structure and other properties of ethene because of its place as the simplest double-bonded organic molecule. Thus, along with ethane and ethyne (acetylene), ethene is the subject of much current work in spectroscopy. This work combines experiment and theory in a mutually dependent manner. Comparison of high-resolution experimental spectra with spectra calculated according to various models can establish which models are most successful in describing reality. On the other hand, theory also informs interpretation of experimental work. In ethene's spectrum, for example, some peaks due to various vibrational modes are very closely spaced (~50 meV). The lifetime broadening of these peaks (which have short lifetimes and therefore uncertain energies due to the Heisenberg uncertainty principle) is 90-100 meV, so the peaks overlap. Thus, improving on the spectral resolution in this experiment (55 meV) would not reveal any further information. Even at this fundamental limit of resolution, empirical fits to determine the relative importance of various vibrational modes give ambiguous results; therefore, any further clarification on this matter must come from improved theory rather than improved spectroscopy.

Research conducted by J. Bozek (Berkeley Lab), T.X. Carroll (Keuka College), J. Hahne (Oregon State University), L.J. Saethre (University of Bergen, Norway), J. True (OSU), and T.D. Thomas (principal investigator, OSU), using the spherical-sector electrostatic analyzer at Beamline 9.0.1. Funding: Office of Basic Energy Sciences of the U.S. Department of Energy, National Science Foundation (Grant No. CHE-94083868), and the Research Council of Norway.

Publications about this experiment: J. Bozek, T.X. Carroll, J. Hahne, L.J. Saethre, J. True, and T.D. Thomas, Phys. Rev. A 57, 157 (1998).

4. NEWS FROM MARCH 6 USERS' EXECUTIVE COMMITTEE MEETING
(contact: w_meyer-ilse@lbl.gov)

The ALS Users' Executive Committee (UEC) met on Friday, March 6, at Berkeley Lab. The meeting's highlights included appearances by Laboratory Director Charles Shank, who reported on the February 24 meeting of the ALS Science Policy Board, and Laboratory Deputy Director Pier Oddone, who described a new LBNL task force aimed at planning a world-class user program for the ALS (see ALS News Vol. 96).

In other business, the UEC selected Steve Kevan, Professor of Physics at the University of Oregon, as its Vice Chair for 1998. Kevan will move up to UEC Chair in 1999. The UEC also set the date for this year's ALS Users' Association Annual Meeting for Thursday and Friday, October 22 and 23.

5. ACTIVITIES FOR APRIL-MAY SHUTDOWN
(contact: jpharkins@lbl.gov)

As April 12 approaches, ALS users can prepare for a seven-week respite from experimenters' hours, but ALS technical staff are gearing up for a busy stretch. The ALS's first planned shutdown since June 1997 will extend from April 12 to May 24, with startup beginning May 26 and user operations scheduled to resume on June 3.

One of the big activities for this shutdown (it's always exciting to have 23 metric tons of metal in the air!) is the installation of the new 10-cm-period undulator (U10) in Sector 10. The U10 will provide light for Beamline 10.0.1, most of whose components have recently been moved from Beamline 9.0.1 (see item #3 above).

In other installations, Beamlines 10.0 and 4.0 will gain front-end components, and a vacuum window recently reconditioned for higher voltage (see ALSNews, Vol. 96) will be installed in storage-ring rf cavity #2. Survey crews will survey and realign the booster, a new mirror tank will go in at Beamline 8.0.1, and a host of other activities will take place in the interstices of the major projects.

Users or staff with questions or concerns about shutdown activities should contact Joe Harkins by email (jpharkins@lbl.gov) or phone (510-486-7486, or ext. 7486 from Lab phones).

6. NEW DATA SHEETS AVAILABLE
(contact: alrobinson@lbl.gov)

The ALS is in the process of publishing two-page data sheets for each of its beamlines and endstations. The data sheets' purpose is to provide prospective ALS users with basic information, including diagrams, tables of specifications, text describing capabilities, illustrative examples of performance or applications, and contact information.

The 20 data sheets published so far are available in portable document format (PDF) on the Web. If you do not have Web access and would like to request a list of data sheets, send email to alsuser@lbl.gov with "send data sheet list" in the subject line.

7. WHO'S IN TOWN: A SAMPLING OF ALS USERS

To highlight the richness of our user community and help introduce recent arrivals, we offer this listing of some of the experimenters who will be collecting data between now and April 12, when our shutdown (see item #5 above) begins.

Beamline 1.4: Hoi-Ying Holman (Berkeley Lab) will investigate microbial transformation of organic contaminants in geologic materials. Richard Saykally and Kevin Wilson (U. California, Berkeley) will conduct a micro-infrared study of water jets.

Beamline 9.0.2.1: Dan Neumark (U. California, Berkeley) and group members W. Sun, K. Yokoyama, and J. Robinson will study ultraviolet photodissociation dynamics of hydrocarbons, probing the isomeric structure of the radical products.

Beamline 9.3.2: Kannan Krishnan (Berkeley Lab) will make x-ray magnetic circular dichroism and x-ray absorption spectroscopy measurements of novel ruthenium-substituted manganites. Sang-Koog Kim (Berkeley Lab) will conduct standing-wave-enhanced magnetic circular dichroism to measure depth-dependent magnetism in bilayer systems such as Pd/Co and Co/Fe. Han-Woong Yeom and Tony Huff (Research Center for Spectrochemistry, U. of Tokyo), X. Zhou (Pennsylvania State U.), and Ed Moler and Zahid Hussain (Berkeley Lab) will do a surface core level shift photoelectron diffraction study of the carbon-terminated 3C-SiC(001) surface reconstruction.

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

Beam reliability for the last two weeks was 77.3% overall and 84.1% for user shifts. Reliability was affected by an outage in linac klystron #2 (see ALSNews, Vol. 98), by a number of fast pressure dips in the low conductivity water system, and by a loss of flow on a water-cooled blank-off flange on the storage ring, which caused a temperature interlock trip.

Long-term and weekly operations schedules are available on the Web (http://www-als.lbl.gov/als/als_ops/schedules/). Weekly operations scheduling meetings are held on Fridays at 3:30 p.m. in the Building 6 conference room. The Accelerator Status Hotline at (510) 486-6766 (ext. 6766 from Lab phones) features a recorded message giving up-to-date information on the operational status of the accelerator.