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.

Previous Issues are available.


ALSNews           Vol.2           November 8, 1994

Table of Contents


    1. ADMINISTRIVIA  
    2. OPERATIONS UPDATE  
    3. BEAMLINE 9.0.1: AT-WAVELENGTH TESTING OF EUV OPTICS UNDERWAY
    4. ALS HOSTS INFRARED WORKSHOP 
    5. ALS INFORMATION ON WORLD WIDE WEB
    6. LONG-TERM SCHEDULING INFORMATION 

1. ADMINISTRIVIA
(contact: ALSNews@lbl.gov)

Many thanks to all of you who responded to last week's premier issue of ALSNews, an electronic newsletter dedicated to issues concerning users of the Advanced Light Source. We have received positive responses from all over the world, a comforting reassurance that ALSNews is already reaching and serving our geographically scattered user community.

The first few issues of ALSNews are being sent to a standard distribution list of people we thought might be interested in subscribing. In early December, only those persons who have asked to be placed on the permanent newsletter distribution list will continue to receive ALSNews. If you haven't responded yet, please email alsnews@lbl.gov and include your complete email address in the body of the message. We would also appreciate receiving suggestions for the information or topics you would like to see covered in ALSNews.

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

Operations for the week of November 6 thru November 12 will include the normal eight hour maintenance period on Monday; accelerator physics work on Tuesday including storage ring beam position monitor characterization studies, tune resonance mapping, 1.9 GeV storage ring characterization, and local bump software tests; and nine user shifts beginning Wednesday owl shift with the standard 320 bunch 400 mA operation. Storage ring refills will normally be made at 200 mA and user operations for the week conclude at 11 pm Friday evening. NOTE: Next week will include two bunch operation on the November 16, 17, and 18 owl shifts.

The attempt to ramp the storage ring energy to 1.9 GeV last week was not only successful but went extremely smoothly. Magnets were automatically set to values calculated for every energy step from formulas that had been derived directly from magnetic measurements, including terms for remnant fields and saturation effects. In this way, no beam at all was lost while ramping to 1.9 GeV, and the tunes stayed within 0.03 from their starting values. The closed-orbit deformations amounted to about 0.3 mm (horizontally) and 0.1 mm (vertically); the steerer magnets were only scaled linearly, without applying any further orbit correction scheme. Beam lifetime was above 20 hrs. at 1.9 GeV (50 mA), somewhat lower than customary for 1.5 GeV at this current

3. BEAMLINE 9.0.1: AT-WAVELENGTH TESTING OF EUV OPTICS UNDERWAY
(contact: jbokor@lbl.gov)

Point diffraction interferometry, a new technique for at-wavelength testing of extreme ultraviolet (EUV) optical components, is now in use at the 8-cm-period undulator beamline 9.0.1. A group led by Jeffrey Bokor of the Center for X-Ray Optics at LBL and the University of California, Berkeley, has implemented a point-diffraction interferometer (PDI). The PDI's key element, fabricated at Lawrence Livermore National Laboratory, is a partially-transmitting membrane with an array of pinholes in it. When light from an optical component under testing illuminates this membrane, the resulting interferograms yield information about the quality or defects of the optical component. The first interferograms, generated by a zone plate lens using a wavelength of 120 angstroms, indicate the PDI is working well and that the coherent undulator light is well-suited to interferometric methods. Near-range plans for Bokor's group are to test other, more complex components for use in EUV lithography.

4. ALS HOSTS INFRARED WORKSHOP
(contact: nvsmith@lbl.gov)

The successful implementation and utilization of the U2B infrared microspectroscopy beamline by Gwyn Williams and co-workers on the VUV ring at the National Synchrotron Light Source (NSLS) for the study of a wide range of problems in materials science has raised the question of installing a similar facility at the ALS. To explore this issue, an informal workshop on "Infrared Microspectroscopy with Synchrotron Radiation" was held at LBL on October 21 immediately following the conclusion of the ALS Users' Association Annual Meeting. More than 40 participants gathered to review the performance of the NSLS beamline, discuss the possibility of an infrared beamline at the ALS, and begin the process of forming a user group to help define the technical specifications for the beamline. An infrared beamline at the ALS could be ready as early as the fall of 1995.

Infrared spectroscopy has been a mainline analytical tool for decades, both in industry and in the laboratory, owing to its ability to identify molecular constituents of complex materials from their vibrational spectra (molecular fingerprints). In the last decade, advanced optics and detectors have made spatially resolved infrared spectroscopy (microspectroscopy) a popular technique for the analysis of inhomogeneous samples and small particles, and IR spectromicroscopes based on Fourier-transform spectrometers are commercially available. These instruments make use of a black-body (thermal) source, which generates a larger photon flux than a synchrotron source over much of the infrared spectrum but is limited in brightness because of the large solid angle into which it radiates. Over the wavelength range from 1 to 1000 microns, for example, the NSLS VUV ring is at least 300 times brighter.

At the workshop, John Reffner of Spectra-Tech, Inc., reviewed the performance of an IR microspectroscope made by his company, including a comparison of results with the NSLS VUV ring as the source against those with a conventional source. Larry Carr of Grumman Research described the U2B beamline, its performance, future enhancements, and some of its research applications. Carl Zimba of the Polaroid Corporation outlined the application of IR microspectroscopy to the particular problem of multilayered photographic film, including the use of an aperture to achieve a spot size of 3 microns. Kenneth Ward of Hewlett-Packard completed the scientific presentations with an analysis of successful experiments aimed at identification of isolated small particles with dimensions less than the diffraction-limited size.

5. ALS INFORMATION ON WORLD WIDE WEB
(contact: jccross@lbl.gov)

Several subscribers to ALSNews requested information on the current and future beamlines and areas of research planned for the ALS. This information is available on the World Wide Web on the ALS Beamline page. From NCSA's Mosaic browser, choose "Open URL" from the File menu and type: http://www-als.lbl.gov/als/als_users_bl/als_bl_chart.html

6. LONG-TERM SCHEDULING INFORMATION
(contact: rmmiller@lbl.gov)

The next shutdown for new installations will be January 2-February 17, 1995. The last user shift before the holidays and shutdown will be day shift on December 21, 1994, and the first scheduled user shift after the shutdown is swing shift on February 22, 1995. During the shutdown, engineers will remove the 5-cm-period undulator on beamline 7.0 and change its vacuum chamber to allow a minimum gap of 1.4 cm (down from 2.3 cm), increasing the beamline's available photon energy range. Other plans include front-end connections for Beamline 7.3, mirror installation for branchline 9.0.2, improvements to the rf system, and replacement of the linac filament.