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. 48           March 20, 1996

Table of Contents


    1. OPERATIONS UPDATE
    2. PREVIEW OF SHUTDOWN ACTIVITIES
    3. TEACHERS HAVE ENLIGHTENING ADVENTURE AT ALS
    4. GORDON RESEARCH CONFERENCE ON ELECTRON SPECTROSCOPY
    5. USER ADVISORIES AND ALS PUBLICATIONS ON THE WEB

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

Beam availability for the last two weeks was 92.6% overall and 92.2% during user shifts.

Operations Summary for March 20 - April 8

Mar 20, 00:00- Mar 25, 07:15  1.9-GeV/260-mA/320-bunch user operations
Mar 25, 07:30-24:00           Maintenance & Startup
Mar 26, 00:00-24:00           Accelerator Physics
Mar 27, 00:00-08:00           User Scrubbing & Special Operations
Mar 27, 08:00- Apr 01, 07:15  1.5-GeV/400-mA/320-bunch user operations
Apr 01, 07:30-24:00           Maintenance & Startup
Apr 02, 00:00-24:00           Accelerator Physics
Apr 03, 00:00-08:00           User Scrubbing & Special Operations
Apr 03, 08:00- Apr 08, 07:15  1.9-GeV/260-mA/320-bunch user operations

Weekly operations scheduling meetings: Fridays at 3:30 p.m. in the Building 6 conference room.

** FEEDBACK-ON, FULL-CURRENT OPERATION AT 1.5 GeV **
Feedback-on operation at full current (400 mA, multi-bunch, 1.5 GeV) is now available to users on request. Beam lifetime measurements in this operating mode will be made during the accelerator physics run this week.

2. PREVIEW OF SHUTDOWN ACTIVITIES
(contact: tadowns@lbl.gov)

On April 15 at 8:00 a.m., the ALS will shut down for installation of a new wiggler and other equipment. The installation work is slated to take four weeks, followed by one week of startup time, and user beamtime is scheduled to resume on May 22. The task that determines the length of this shutdown is the installation of a 16-cm-period wiggler to provide light for protein crystallography beamline 5.0. While this is going on, a host of smaller tasks will be completed, including the installation of most of the front end (the portion of the beamline inside the storage-ring shielding) and other parts of Beamline 5.0.

A wiggler operates on principles similar to those of an undulator: many oscillations of the electron beam over a few meters produce higher photon flux than a single bend magnet of the same magnetic field strength (the wiggler flux is the bend-magnet flux multiplied by the number of magnetic pole pairs in the wiggler, 38 for the Beamline 5.0 wiggler). The key difference between a wiggler and an undulator is that each pole pair of a wiggler acts like a short bend magnet, deflecting the electron beam through an angle that is large compared to the natural emission angle of synchrotron radiation. As a result, a wiggler produces a continuous photon spectrum as a bend magnet does, whereas an undulator's spectrum consists of a well-defined series of harmonic frequencies. Magnetic measurements on the Beamline 5.0 wiggler show its peak field at minimum gap (14 mm) to be 2.12 T, which is 6% higher than the design specification. The rms magnetic field errors, at 0.16%, are the lowest of any of the ALS insertion devices built to date.

3. TEACHERS HAVE ENLIGHTENING ADVENTURE AT ALS

In March the ALS took another step forward in its outreach efforts by holding its first workshop for teachers. Inspired by the enthusiastic response of local teachers to ALS activities at the LBNL Open House last fall, the workshop was designed to expand the links between the ALS and local science educators and to make the ALS accessible to teachers as an educational resource. The two-part workshop, entitled "Adventures in Light and Science," attracted 70 applicants from 55 different schools. The 40 teachers accepted for the workshop had the opportunity to see the ALS from the inside out during the first session on March 4, as ALS staff conducted guided tours of the accelerator, booster ring, and storage ring. Other activities included demonstrations of vacuum, low-temperature, and magnet effects.

Armed with plenty of questions, the teachers returned to the ALS on Saturday, March 16 to try some hands-on activities which explored the properties of light in "Puzzling Polarizers," and the relationship between electricity and magnetism in "Moving Electrons". The activities were designed to build on concepts related to the ALS and to be suitable for use in classrooms over a broad range of grade levels. A highlight for many teachers was a trip to a beamline with one of several ALS scientists, who discussed the research at their beamlines and explained how the beamlines worked.

Much of the success of the workshop for teachers was due to the enthusiastic support of ALS staff and scientists who willingly gave their time and assistance to make this a truly unique `adventure in light and science' for the teachers.

** NOTHING IS EVER AS SIMPLE AS IT APPEARS **
Developing hands-on activities for the `Adventures in Light and Science' workshop for teachers became a learning adventure in itself for ALS staff -- we learned that even simple activities such as an exploration of electromagnetism using a `jumping wire' (a current-carrying wire running between two magnets `jumps' up or down depending on the direction of the current) could inspire "charged" discussion on a wide range of topics:

  - What makes a material magnetic?
  - Why is the earth a magnet? Why have the poles of the earth reversed 
    several times?
  - If you know the direction of a current, how can you determine the poles 
    of a magnet?
  - How do birds use the earth's magnetic fields to navigate?
  - What causes the Northern Lights?
  - What is the difference between permanent magnets and electromagnets?
  - How does the movement of electrons cause the properties of a material 
    to change?

  - Moving Electrons - a hands-on activity unit
  - Puzzling Polarizers - a hands-on activity unit
  - "Inside the ALS" - an informative poster for teachers and students with 
    a hand-out on suggestions for using the poster in the classroom
  - Top Ten Questions People Ask about the ALS (a fun trivia sheet of cool 
    facts)
  - Mass, Energy, The Speed of Light - It's Not Intuitive!
  - A Day in the Life of an ALS Electron - a lighter look at what an 
    electron does at the ALS

4. GORDON RESEARCH CONFERENCE ON ELECTRON SPECTROSCOPY

The Gordon Research Conference on Electron Spectroscopy will feature several members of the ALS user community. The conference will be held July 7-12, 1996 at New England College, Henniker, NH. To obtain an application form, fax your request to Neville Smith at (510) 486-4960 or to the GRC office at (401) 783-7644. The conference program is as follows:

Sunday, July 7: (p.m.) Spin-Polarization with Peter Johnson and Uwe Becker

Monday, July 8: (a.m.) Low Dimensional Materials with Ralph Claessen, Kurt 
Schoenhammer, and Atsushi Fujimori; (p.m.) Lasers and Synchrotrons with 
Nora Berrah and Laurent Nahon

Tuesday, July 9: (a.m.) Advanced Spectroscopy with Horst Schmidt-Boecking, 
Brad Armen, and Steve Southworth; (p.m.) Photoelectron Diffraction and 
k-space Mapping with Jurg Osterwalder and Alex Bradshaw

Wednesday, July 10: (a.m.) Spectromicroscopy with Harald Ade, Tony Warwick, 
and Ernst Bauer; (p.m.) High Tc Superconductivity et al. with Juan Carlos 
Campuzano and Dan Dessau

Thursday, July 11: (a.m.) Molecular Processes with Darrah Thomas, Albert 
Stolow, and Mike White; (p.m.) Keynote Address by Dick Brundle, Confessions 
of an Electron Spectroscopist: Oxford University to Silicon Valley

5. USER ADVISORIES AND ALS PUBLICATIONS ON THE WEB

The ALS User Advisories and a list of ALS publications are now available on the World Wide Web. The User Advisories are short information sheets about issues concerning users of the ALS. Users can browse through full-text versions of these. The publication list includes general ALS publications available from the user office as well as information about how to request them. We will be updating these listings periodically to keep pace with new publications and revisions. A review and update of the User Advisories is currently under way.

These new resources are available on the ALS Center's Information page, which you can reach by pointing your browser to http://www-als.lbl.gov/als/als_info.html.