THE ELECTRONIC ALADDIN NEWSLETTER NO. 27 August/December 2000

First of all, we would like to thank the Users and Friends of the SRC for their tireless support during this busy year.

Best wishes for a successful New Year!

1. HIGHLIGHTS FROM THE SRC USERS MEETING AND WORKSHOP

The SRC Users Meeting on Oct. 27 brought together a wide range of topics.  We heard about zinc-metabolizing bacteria that thrive in the hostile environment of flooded mines (see below), about brain cells affected by Alzheimer's disease, high temperature superconductors, spin-polarized electrons in spintronics, and much more.

The subsequent SRC Workshop on Oct. 28 was dedicated to atomic and molecular physics and chemistry with a discussion of current topics and future directions. For example, a series of experiments has demonstrated that dipole approximation breaks down at much lower photon energies than anticipated. The holy grail of the complete measurement was addressed, where not only the transition probabilities, but also the phases are determined using sophisticated alignment techniques with laser light or difficult polarization measurements of fluorescence photons and photoelectrons. Absolute oscillator strengths of atoms and ions deep in the ultraviolet are critical for obtaining quantitative results from the new space-based telescopes about the development of galaxies. For more "post-Workshop" information (photos, book of abstracts, etc.) visit

http://www.src.wisc.edu/news/usermeeting/Workshop.htm

Cliff Olson was elected the new Chair of the Users Advisory Committee.  Newly-elected members are Gelsomina (pupa) DeStasio, Juan Carlos Campuzano, Dave Lynch, and Adam Kaminski as student member.

2. SRC RENEWAL

The National Science Foundation and the SRC have reached a verbal agreement on the funding for the next five years. The revised budget has to be submitted and the final contracts have to be signed before the agreement becomes official, but the proposed agreement calls for inclusion of the low emittance lattice work, the proposed User instrumentation, and a new High Throughput Monochromator for the new U2 undulator. As with all facilities, there will be a review after the end of three years.

3. ZINC METABOLIZING BACTERIA

Bacteria can adapt to extreme conditions, such as the solution of toxic metals present in flooded mines. An example are sulfate-reducing bacteria, which may be one of the oldest forms of life on Earth. Ancient sulfate-reducing bacteria left their first mark on their environment in pyrite minerals (FeS2) as old as 3400 million years. Strong support for such a role is now provided by collaboration led by Jill Banfield (UW-Madison), who have discovered sulfate-reducing bacteria that can tolerate low levels of oxygen and can precipitate zinc sulfide minerals. This work included spectro-microscopy results obtained at the SRC by Gelsomina "pupa" DeStasio and Ben Gilbert that provide the spatial distribution of metals and their chemical state in biofilms formed by these bacteria. The results may have implications for bioremediation and provide clues to processes that may have been more widespread in the geologic past. For details see Science 290, 1744 (December 1, 2000), including the cover, and the Perpective by C. Vasconcelos and J.A. McKenzie on p. 1711 in the same issue.

4. NEW U2 UNDULATOR PRODUCES FIRST LIGHT

During the two-week development period of November 27-December 8, the new Danfysik undulator was installed in long straight section 2. It replaces the historic 1980 Berkeley/Stanford Halbach undulator, which was on loan to the SRC. The new undulator has a pure permanent magnet design with 101 full strength poles and a period of 68.2 mm.

Specifications called for reaching 7.8 eV at the low end for magnetic materials research and nanolithography studies and for operating at 250 to 350+ eV for carbon spectroscopy. Ninth harmonic radiation with 90 % nominal flux was also required.  The installation of the new pure permanent magnet undulator in long straight section 2 went very smoothly and routine accelerator operation was recovered rapidly. Preliminary observations of the undulator spectrum with the high throughput Maximum monochromator indicate that it achieves the design goal of 7.8 eV in the first harmonic at a minimum gap of 23.8 mm. Detailed study of the higher harmonics is currently under way. Comparisons of the ninth harmonic of 7.8 eV (70.2 eV) with theoretical models indicate that the field quality of the device is very good. Characterization of the undulator radiation, alignment, and beamline conditioning are continuing in preparation for the installation of the 5 meter Wadsworth beamline to be completed in 2002.

Pictures of the installation process can be viewed.

5. NEW SCIENTA SPECTROMETER COMING

A second Scienta spectrometer has been ordered to satisfy the demand for high-resolution, angle-resolved photoemission experiments. It is due late February 2001. The future configuration of the two Scientas was discussed in a luncheon at the SRC Users Meeting, including desirable improvements. A layout of the measurement and sample chamber for the new spectrometer was produces by Chad Gundelach and Hartmut Hochst and sent to previous Scienta Users. The SRC is soliciting input now on the arrangement. Please send requests for drawing and suggestions to Hartmut Hochst

6. POSTDOC POSITION FOR THE SCIENTA

A new postdoc position is funded by the UW-Madison Graduate School in support of sophisticated experiments at the Scienta analyzers. The starting date is any time after April 1, 2001. Please send applications to James Taylor, Executive Director of the SRC.

7. NEXT BEAMTIME PROPOSAL DATE IS FEB. 1, 2001

The call for beamtime proposals is going out for the February 1. deadline. Detailed information and a Word template can be downloaded.

8. CONGRATULATIONS TO SRC RESEARCHERS

Prof. Marshall Onellion (UW-Madison) received a Certificate of Commendation from the Governor of Wisconsin for his ten years of dedication as voluntary physics teacher with students from Stoughton High School. SRC staff and researchers coming to the SRC on weekends are familiar with the Saturday morning enrichment classes taught by Marshall.

Prof. T. K. Sham (U. Western Ontario), a regular user of the SRC, was elected the Vice Chair of the International XAFS Society (IXS). He will become Chair in 2003.

The year 2000 Aladdin Lamp Award of the SRC was presented at the Users Meeting to Kyle Altmann (U. Wis. Madison) and Dah-An Luh (U. Ill. Urbana). The award recognizes excellence in synchrotron radiation research performed at the SRC as part of an educational program. Kyle determined the electronic states in materials that are important for magnetoelectronics, such as permalloy. Dah-An contributed to the development of photoelectron holography, a technique that maps out the positions of surface atoms in three dimensions and element-specific. He also mapped the interface structure of SiO2/Si and proved that d-band quantum well states exist.

An extra SRC Executive Director's Award was presented to Adam Kaminski (U. Ill. Chicago) at the SRC Users Meeting for going beyond the call of duty to help the SRC in a time of need. At the NSF site visit for the renewal of the SRC he was asked by the committee to give a presentation on overnight's notice and pulled off an impressive talk on high resolution ARPES studies of many body effects in high temperature superconductors using the Scienta analyzer.