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
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,
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
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,
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
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