Another Users'
Meeting,
Another Record Attendance
by Art Robinson
Thanks to a surge in eleventh-hour registrations,
an overflow crowd of more than 400 users, staff, and vendors
materialized to enjoy a successful ALS Users' Meeting, with
a program chock full of science highlights and a dozen workshops,
all spread over three days from October 21–22.
During the popular vendor reception
and poster session,
displays spilled over from the ALS patio into Building 7.
Berkeley Lab Director Stephen Chu started
off the proceedings with encouraging words about the planned
onsite user lodging facility and promised his support for
keeping the ALS a top user facility in all categories, from
accessibility to scientific output. Acting ALS Director Janos
Kirz began his report on the state of the ALS by pointedly
reiterating the ALS mission: to support users in doing outstanding
science in a SAFE ENVIRONMENT. He then reviewed progress on
the accelerator, beamline, and science fronts, highlighting
an outstanding report card from the 2005 Basic Energy Sciences
(BES) review of the ALS.
Michael Lubell (City College of New York
and American Physical Society) reviewed the outlook for the
federal science budget, including both positive and negative
factors; the bottom line to users: get politically active.
In her annual "View from Washington" report, Department
of Energy (DOE) Associate Director of Science for BES Pat
Dehmer summarized her efforts to convince federal budget makers
that, if light sources are to remain competitive, they cannot
continue to operate on flat funding. At the end of her talk,
she presented retiring ALS Director Daniel Chemla with a DOE
Distinguished Associates Award, and the audience saluted him
with a standing ovation.
Pat Dehmer presented Daniel Chemla
with a DOE Distinguished Associates Award.
In other Thursday morning presentations,
ALS accelerator physicist Christoph Steier reviewed progress
and plans toward the new top-off mode of operation expected
to be fully operational in 2007, as well as other accelerator
improvements. Users Services leader Gary Krebs described upcoming
changes in the badging process, and Science Director Neville
Smith unveiled a draft version of a new general sciences proposal
process and invited user input. Users' Executive Committee
(UEC) chair Greg Denbeaux (The University at Albany) conducted
a town hall meeting that covered several issues, including
candidates for the upcoming UEC election.
Thursday afternoon and Friday morning
were devoted to keynote presentations and science highlights,
while Friday afternoon and Saturday were dedicated to a set
of 12 workshops. All talks and workshops are described on
the Meeting
Web site. Thursday evening saw the inauguration of "public
science" lectures as part of the meeting program. Co-sponsored
by the ALS and the Berkeley Lab Friends of Science, Joachim
Stöhr, newly appointed director of the Stanford Synchrotron
Radiation Laboratory, spoke to almost 200 meeting attendees
and members of the public on "The Mysteries of Magnetism:
From Physical Attraction to Spin Doctors."
Meeting attendees enjoyed barbecue
and corn-on-the-cob alfresco.
A pleasant California autumn evening
provided the perfect environment for the now-traditional barbecue
dinner on the ALS patio on Friday. Program co-chairs Simon
Morton (Berkeley Lab's Physical Biosciences Division) and
Jinghua Guo (ALS) then hosted the user award session. This
year there were two student poster prizes: Michelle Weinberger
(University of California, Los Angeles) won the first prize,
sponsored by Oxford Instruments, and Benjamin Yuhas (University
of California, Berkeley) took the second prize, sponsored
by Vacuum Generators. Ron Slater and Ed Wong (Berkeley Lab's
Engineering Division) each bagged individual Tim Renner User
Services Awards.
The Halbach Award for innovative instrumentation
was won by Elke Arenholz (ALS) and Soren Prestemon (Engineering
Division) for the design and implementation of a vector magnetometer
for soft x-ray studies. The Shirley Award for scientific achievement
went to Craig Taatjes (Sandia National Laboratories), Terrill
Cool (Cornell University), Philip Westmoreland (University
of Massachussetts), and their colleagues for the surprising
and far-reaching discovery of enols in flames. And in a special
presentation, Wei-lun Chao (University of California, Berkeley,
and Berkeley Lab's Center for X-Ray Optics) took possession
of the Werner Meyer-Ilse prize for outstanding work by a young
researcher, awarded every three years at the International
X-Ray Microscopy Conference.
Disorder-induced
microscopic
magnetic memory
The magnetic-recording industry deliberately
introduces carefully controlled disorder into its materials
to obtain the desired magnetic properties. But as the density
of magnetic disks climbs, the size of the magnetic domains
responsible for storage must decrease, posing new challenges.
Beautiful theories based on random microscopic disorder have
been developed over the past ten years. To directly compare
these theories with precise experiments, an American - European
team, led by researchers from the University of Washington,
Seattle, first developed and then applied coherent x-ray speckle
metrology to microscopic magnetic domains in a series of thin
multilayer perpendicular magnetic materials of varying disorder.
Their results, at odds with all previous theories, have set
a new reference point for future theories. Full
story.
Publication about this research: M.S.
Pierce, C.R. Buechler, L.B. Sorensen, J.J. Turner, S.D. Kevan,
E.A. Jagla, J.M. Deutsch, T. Mai, O. Narayan, J.E. Davies,
K. Liu, J. Hunter Dunn, K.M. Chesnel, J.B. Kortright, O. Hellwig,
and E.E. Fullerton, "Disorder-induced microscopic magnetic
memory," Phys. Rev. Lett. 94,
017202 (2005).
Contact: Michael S. Pierce, hatter@u.washington.edu
Crystal structure
of a protein
kinase A complex
Protein kinase A (PKA) is an enzyme that
regulates processes as diverse as growth, memory, and metabolism.
In its unactivated state, PKA exists as a tetrameric complex
of two catalytic subunits and a regulatory subunit dimer,
but when the intracellular signaling molecule cyclic adenosine
monophosphate (cAMP) binds to the regulatory subunit, it facilitates
dissociation and activation of the catalytic subunits. While
separate structures of these subunits were previously known,
a group from the University of California, San Diego, is the
first to determine (to a resolution of 2.0 Å) the structure
of the PKA catalytic subunits bound to the regulatory subunit.
The structure of the complex clarifies the mechanism for PKA
inhibition, and its comparison with the structure of cAMP
bound to the regulatory subunit hints at how cAMP binding
drives its activation. Full
story.
Publication about this research: C. Kim,
N.-H. Xuong, and S.S. Taylor, "Crystal structure of a
complex between catalytic and regulatory (Rla)
subunits of PKA," Science 307,
690 (2005).
Contact: Susan Taylor, staylor@ucsd.edu
Engineering metal
impurities in
multicrystalline silicon solar cells
Transition metals are one of the main
culprits in degrading the efficiency of multicrystalline solar
cells. With a suite of x-ray microprobe techniques, a multi-institutional
collaboration led by researchers from the University of California,
Berkeley, and Berkeley Lab studied the distribution of metal
clusters in a variety of multicrystalline solar cells before
and after processing. Their discovery that the size, spatial
distribution, and chemical binding of metals within clusters
is just as important as the total metal concentration in limiting
the performance of multicrystalline silicon solar cells led
to the concept of defect engineering by optimizing growth
and processing sequences to trap metals in their least harmful
state. Full
story.
Publications about this research: T.
Buonassisi, A.A. Istratov, M.A. Marcus, B. Lai, Z. Cai, S.M.
Heald, and E.R. Weber, "Engineering metal-impurity nanodefects
for low-cost solar cells," Nature Materials
4, 676 (2005); T. Buonassisi, A.A. Istratov,
M. Heuer, M.A. Marcus, R. Jonczyk, J. Isenberg, B. Lai, Z.
Cai, S. Heald, W. Warta, R. Schindler, and E.R. Weber, "Synchrotron-based
investigations of the nature and impact of iron contamination
in multicrystalline silicon solar cell materials," J.
Appl. Phys. 97, 074901 (2005); T. Buonassisi,
M.A. Marcus, A.A. Istratov, M. Heuer, T. F. Ciszek, B. Lai,
Z. Cai, and E.R. Weber, "Analysis of copper-rich precipitates
in silicon: Chemical state, gettering, and impact on multicrystalline
silicon solar cell material," J. Appl. Phys.
97, 063503 (2005).
Contact: Andrei A. Istratov, istratov@berkeley.edu
Protein flips
lipids
across membranes
Found ubiquitously in both bacteria and
humans, membrane proteins of the adenosine triphosphate (ATP)–binding
cassette (ABC) transporter family have been implicated in
both antibiotic and cancer-drug resistance. The mechanisms
used by these proteins to expel toxins from cells therefore
represent key targets for the development of drugs designed
to combat the growing problem of multidrug resistance. Toward
this end, researchers from The Scripps Research Institute
have succeeded in crystallizing MsbA—an ABC transporter
protein—together with a substrate (the molecule to be
transported) and a hydrolyzed (spent) form of the nucleotide
ATP, the transporter's source of chemical energy. The resulting
molecular complex is caught at a moment following the transporter's
"power stroke," the force-generating part of the
transport cycle. This snapshot suggests a mechanism by which
the substrate molecule gets flipped head-over-tail from one
side of the membrane to the other, on its way out of the cell.
Full
story.
Publication about this research: C.L.
Reyes and G.A. Chang, "Structure of the ABC transporter
MsbA in complex with ADP·vanadate and lipopolysaccharide,"
Science 308, 1028 (2005).
Contact: Geoffrey Chang, gchang@scripps.edu
First light at
soft x-ray
femtosecond beamline
The soft x-ray (0.2- to 1.8-keV) branch
of the new Ultrafast X-Ray Facility at Beamline 6.0.1.2 saw
first light on October 4 and is currently undergoing commissioning.
Its complementary hard x-ray (2- to 10-keV) branch is still
under construction and is on schedule for commissioning in
the spring of 2006. Designed for x-ray spectroscopy and diffraction
with 200-femtosecond temporal resolution, Beamline 6.0.1.2
will fill a critical need for the growing ultrafast x-ray
research community at the ALS. Interest in time-resolved,
ultrafast science spans the fields of physics, chemistry,
and biology. Examples of studies that will be possible at
Beamline 6.0.1.2 include solution-phase molecular dynamics,
photoinduced phase transitions in complex materials, bonding
properties of matter at high energy densities, x-ray/laser
ionization dynamics in atomic and molecular systems, and nonlinear
laser/x-ray mixing in solids.
 Beamline
6.0.1.2 is an in-vacuum insertion-device (IVID) version of
the bend-magnet laser-slicing source currently in use at Beamline
5.3.1. The permanent-magnet, dual-mode (undulator/wiggler)
IVID will radiate soft and hard x rays from 120 eV to 10 keV
in both normal and laser-slicing modes. The device, with 50
3-cm periods and a peak magnetic field of 1.5 T, together
with the addition of a new laser with a higher repetition
rate, will result in a thousandfold increase in flux and brightness
over the bend-magnet source. A variable-line-spacing (VLS)
grating spectrograph on the soft x-ray branch will allow a
complete spectrum to be recorded at once, and a streak camera
will serve as the detector for measurements on picosecond
time scales. Future plans call for chicaning straight section
6 to add a half-length, small-gap, elliptically polarizing
undulator (EPU), resulting in a doubling of capacity as well
as the ability to use polarized x rays.
Based on a proposal by principal investigators
Bob Schoenlein (Berkeley Lab's Materials Sciences Division)
and Roger Falcone (University of California, Berkeley), the
Ultrafast X-Ray Facility is the fruit of many years of effort
by Howard Padmore, Phil Heimann, Ernie Glover, and others
in the Experimental Systems Group, as well as Christoph Steier
and many collaborators in the Accelerator Physics and Engineering
Groups. The concept of laser slicing was developed by Alexander
Zholents and Max Zolotorev of Berkeley Lab's Center for Beam
Physics. The beamline is funded by DOE BES.
Contact: Robert Schoenlein, RWSchoenlein@lbl.gov
2006 Davisson-Germer
Prize
awarded to Lew Cocke
 The
American Physical Society has announced that the 2006 Davisson-Germer
Prize has been awarded to ALS user C. Lewis Cocke, University
Distinguished Professor in Physics and Director of the James
R. MacDonald Laboratory at Kansas State University. The prestigious
Davisson-Germer prize was established in 1965 by AT&T
Bell Laboratories to recognize and encourage outstanding work
in atomic or surface physics. Lew's citation reads: "For
a sustained record of novel experimental developments and
new insights into interactions of ion and photon beams with
atoms and molecules." The ALS offers Lew its heartiest
congratulations on this well-deserved honor.
Lew received his bachelor's degree in
physics from Haverford College in 1962 and his Ph.D from the
California Institute of Technology in 1967. He has received
numerous awards, including the Alexander von Humboldt award
and the Max Planck Research Award. He is a Fellow of the American
Physical Society, serving as Secretary-Treasurer of the Division
of Atomic, Molecular and Optical Physics. Lew's research interests
focus on collisions involving multiply charged ions interacting
with electrons, atoms, surfaces, and clusters, as well as
the interaction of intense laser pulses with ion beams, atoms,
and molecules. At the ALS, Lew and his collaborators have
used a "momentum spectrometer" to measure the simultaneous
momentum of charged particles ejected when a beam of ALS photons
interacts with a beam of gas molecules. Highlights of this
work can be found at the links below.
Gas-Phase
Molecules Illuminated from Within
Explosive
Experiment Explores Escaping Electrons
Reminder: Please
submit your
2004–2005 publications
In preparation for the 2005 ALS Facility
Report to DOE, we are asking ALS users to submit their publications
of ALS-related work for the years 2004–2005. Excellent
numbers may help DOE justify increased funding for our facility.
Therefore we need to ensure that all published work—especially
theses—undertaken in full or in part at the ALS is included
in our report. We very much appreciate your efforts—it
is imperative that the publications information that we present
be accurate and inclusive.
To submit publications, go to the ALS
Reporting
Publications Web page and follow the instructions there.
Be sure to search the database first to make sure your publication
hasn't already been entered. When submitting a publication,
if you don't have a certain piece of information (e.g., page
number or month published), type "n/a" in the field.
The User Services Office will attempt to track it down. Be
sure you are using an up-to-date Web browser—Netscape
6 or 7 or Microsoft Internet Explorer 5.0 or greater. If you
don't, you will lose data when you hit the "Back"
key.
Remember, if it's on your CV, and all
or part of the work was done at the ALS, it should be in our
database!
Contact: Jeff Troutman, JPTroutman@lbl.gov
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