Bringing the
mesoscale into focus
by Julie McCullough
X-ray tomography is the first high-throughput
imaging technology that generates images of whole, hydrated
cells at better than 60 nm resolution. With it, researchers
from Berkeley Lab have obtained three-dimensional views of
the internal structure of whole, hydrated Saccharomyces
cerevisiae cells, bridging the mesoscale resolution "gap"—the
middle area between light (200 nm) and electron microscopy
(3 Å). With the ALS transmission x-ray microscope, data
collection is fast (under 3 minutes) and relatively easy (like
light microscopy), producing high-resolution, absorption-based
images (like electron microscopy) that provide contrast between
cellular structures and allow for discernment of individual
structures. After data collection, tomographic techniques
are used to reconstruct the original information into quantifiable
three-dimensional views of the entire cell. Through the use
of computer algorithms, the researchers then process the reconstructed
data to create made-to-order images of whole cells and their
internal structures. Full
story.
Publication about this research: C.A.
Larabell and M.A. Le Gros, "X-ray tomography generates
3-D reconstructions of the yeast, Saccharomyces cerevisiae,
at 60-nm resolution," Molecular Biology of the Cell
15, 957 (2004).
Contact: Carolyn Larabell, CALarabell@lbl.gov
Organic matter
in interplanetary dust
by Lori Tamura
Since long before life appeared on Earth,
a constant flux of carbonaceous (carbon-containing) dust has
rained down from the sky, at times accreting as much as a
centimeter deep over the Earth's surface every million years.
Such dust particles are complex assemblages of primitive interplanetary
material left over from the formation of the solar system.
One such interplanetary dust particle (IDP), collected by
NASA from Earth's stratosphere and nicknamed "Benavente,"
was analyzed by researchers from Washington University and
Lawrence Livermore National Laboratory using a variety of
techniques, including synchrotron infrared spectroscopy at
the ALS. The measurements revealed, for the first time in
an IDP, an isotopically anomalous region both depleted in
carbon-13 and enriched in nitrogen-15, located in a host phase
that is organic in nature. These isotopic anomalies provide
valuable clues to the history of the particle and, by extrapolation,
the solar system. Full
story.
Publication about this research: C. Floss,
F.J. Stadermann, J. Bradley, Z.R. Dai, S. Bajt, and G. Graham,
"Carbon and nitrogen isotopic anomalies in an anhydrous
interplanetary dust particle," Science 303,
1355 (2004).
Contact: Christine Floss, floss@wustl.edu
Unusual isotope
effect in Bi2212
by Art Robinson
Magnetism or lattice vibrations? After
almost 18 years of intense experimental and theoretical effort
since the discovery of the first cuprate high-temperature
superconductor (HTSC), physicists still do not know the origin
of this most intriguing of solid-state phenomena. Working
at the Advanced Light Source, a team of Berkeley Lab, University
of California, Berkeley, and University of Tokyo researchers
has come up with evidence from angle-resolved photoemission
spectroscopy (ARPES) that strongly implicates lattice vibrations,
but in an unconventional way that leaves room for magnetism
as well. Full
story.
Publication about this research: G.-H.
Gweon, T. Sasagawa, S.Y. Zhou, J. Graf, H. Takagi, D.-H. Lee,
and A. Lanzara, "An unusual isotope effect in a high-transition-temperature
superconductor," Nature 430,
187 (2004).
Contact: Alessandra Lanzara, ALanzara@lbl.gov
Janos Kirz addresses
staff
at town hall meeting
On September 21, ALS Acting Director
Janos Kirz held a "town hall" meeting to talk about
his perceptions after 100 days on the job, encompassing where
we are now, the Washington scene, recent accomplishments,
and what's coming up, in both the short and long term. He
prefaced his remarks with a brief update on Daniel Chemla,
reporting that Daniel continues to improve slowly and stays
involved in what's happening at the ALS, even suggesting speakers
for next month's Users' Meeting. Janos credits Daniel for
the high credibility that the ALS currently enjoys in Washington,
where he said the ALS is viewed as a world-leading facility
in vacuum ultraviolet and soft x-ray science, with a successful,
productive user program that will nevertheless need to do
more with less in the future. The ALS has a lot to be proud
of, he said, and we need to present it all in the best possible
way.
A statistical snapshot of the ALS showed
that the past trends of user growth coupled with flat funding
are expected to continue, while publications have leveled
off at a healthy level consistent with a mature facility.
Given the projected growth in both users and beamlines and
the consequent crowding, Janos emphasized safety as a top
priority, asking everyone to report any safety hazards. Diversity
issues were also highlighted, and Janos specified two goals
for 2004: increasing the ALS applicant pools of women and
minorities, both of which are underrepresented, and educating
employees about the benefits of diversity in the workplace.
Janos then described some of the ALS's
accomplishments of the past year, including machine improvements,
new beamlines, and new science. A major facility development
was the installation of a new wiggler (W11) in Sector 5 that
will simultaneously allow the optimum operation of femtosecond
slicing work as well as improved protein crystallography operation.
The ALS is also on track to achieve all of this year's goals
for the top-off upgrade, including determining its impact
on users, identifying engineering challenges, and testing
solutions. Four new beamlines came online in the past year—11.0.2
(MES), 8.3.2 (tomography), 12.3.1 (SIBYLS), and 12.2.2 (high
pressure)—and all have begun productive scientific programs.
Janos next cited a litany of recent scientific accomplishments,
ranging from evidence for electron–phonon coupling in
high-temperature superconductors, to the creation of an antiferromagnetic
exchange spring, to imaging 3D objects using lensless coherent
x-ray diffraction.
What does the future hold for the ALS?
For the near term, several new beamlines are under development:
11.0.1 (PEEM-3), 12.3.2 (microdiffraction), 6.0 (femtosecond
phenomena), 4.0.1 (MERLIN), and 2.1 (XM-2). For the long term,
strategic planning efforts are underway with the goal of keeping
the ALS at the cutting edge for the next 20 to 30 years. Ingredients
of such a plan will include facility upgrades, new scientific
programs in line with DOE priorities and Berkeley strengths,
construction of user housing and support buildings, and developments
in detectors, optics, and theory. Criteria for successful
projects are that they will address important scientific questions,
have a strong user group to make the case, and bring new world-class
capabilities to the ALS. Preferably, they will fit with the
ALS mission as well as with the "facts on the ground"
(i.e., there is room to build) and be relatively economical.
These issues will be discussed at the Users' Meeting in October,
where stakeholders are encouraged to provide feedback. The
plan will be finalized in time for a major Department of Energy
review coming up in February.
Wireless networks
available:
Networking do's and dont's
 WIRELESS
NETWORKING. Recently the ALS has installed wireless
networking for users in most areas of Buildings 6 and 80.
Service complies with IEEE standard 802.11a at up to 54 Mpbs
and 802.11b at up to 11 Mbps. These wireless networks are
open; view the available networks in your wireless network
application and select the strongest signal. Users without
wireless networking can plug into an available open network
port on a regular beamline network (NOT the special controls
networks, which cannot access the Internet and should not
be used without special permission). Contact a beamline scientist
for help in determining which network port to use. After connecting
to either the wireless or wired network, go to the NETS
database (a Berkeley Lab LDAP password is required) and fill
out and submit the form there regarding your computer. This
will facilitate reaching you in case there is a problem. If
access to ALS computing resources is required, it may be necessary
to use the wired network or to use the Laboratory's virtual
private network (VPN)
service via the wireless net.
COMPUTER SECURITY. In
the current climate of computer worms, viruses, stolen credentials,
and frequent patching, it is important to keep all computers
up to date and free of undesired programs. The Laboratory
has a strong computer security program, an important component
of which is the active scanning of machines for vulnerabilities
that are considered critical, i.e. those that can lead to
immediate and serious compromises from known attacks. (Note:
an unpatched machine on the Internet will be compromised in
20 minutes, on average, based on a recent study.) An effort
is made to contact the machine owner to resolve the issue,
but it may be necessary to block the machine from the network
on very short notice. In some cases it is not practical to
find the machine owner (or they are not known), so no warning
is possible. In cases where the vulnerabilities are less severe,
the response is reduced—notices are emailed, etc. Only
severe or long-ignored issues generally result in blocking.
Scanning occasionally has undesired side effects, such as
stopping a service on a machine or causing it to crash. This
occurs because there are bugs in the system software. The
Laboratory will soon be scanning all networks open to the
Internet on a daily basis. In the past we have not allowed
ALS networks to be scanned, but this is changing.
WHAT YOU CAN DO. Ensure
that all critical updates are installed on all systems and
that systems are virus- and worm-free. Install and configure
a host-based firewall to provide an extra layer of protection.
Make sure your systems are all correctly registered in the
NETS online database that
is used to contact system owners. Avoid using newly connected
systems for critical data collection, especially for a day
or so after they are connected to the network. Critical machines
are best kept off-net or on the private networks that are
available on some beamlines. Do not use important machines
for email, surfing the Web, or other higher-risk activities.
Use quality passwords, disable unnecessary services, and never
allow passwords to be on the network "in the clear"—use
secure shell or VPN
services to protect remote access. For detailed information,
refer to Chapter 9 of Berkeley Lab's Regulations
and Procedures Manual.
Remotely accessing accounts across the
network exposes your credentials to programs that may have
been modified to collect them. This is especially a problem
when computing in a low-security environment. Many university
computers have been compromised in this way. Be very careful
of where you use your passwords. Passwords used from insecure
or questionable locations should be changed. Passwords used
for remote access should be changed frequently. Keep separate
passwords for different systems. The best way to access remote
services is from your own secure computer using your own copy
of secure shell using public keys rather than regular passwords.
IF YOU HAVE A PROBLEM.
If you have a problem connecting to the wireless or wired
networks, suspect that you have a computer virus or worm problem,
find indications of someone else logging in to your accounts
(files you don't recognize, etc.), or if you suddenly cannot
log in—contact the Help Desk at 486-HELP.
Computer security depends on each of
us.
Contact: Alan Biocca, AKBiocca@lbl.gov
Philip Bucksbaum
colloquium:
Ultrafast quantum control
 Philip
Bucksbaum, the University of Michigan's Otto Laporte Professor
of Physics and Director of the Frontiers in Optical and Coherent
Ultrafast Science (FOCUS) Center, gave last month's ALS colloquium,
titled "Quantum control if you know what you are doing...
or if you don't." The essential tool of quantum control
is the shaped radiation pulse. Such a pulse is generated when
an ultrafast, smooth, large-bandwith laser pulse is passed
through phase and amplitude filters to spread out its various
frequencies into a unique temporal profile. This shaped pulse
can then be used to control dynamics in matter. The objective
is a new quantum state of the physical system, such as a new
chemical, a special kind of light, or an excited state of
a molecule with special properties.
For example, in well-understood systems
such as Rydberg atoms (i.e., where you know what you are doing),
shaped pulses can be used to store bits of information—a
rudimentary form of quantum computing. Shaped pulses can also
be used to manipulate more complicated condensed-phase systems
where the Hamiltonian is unknown (i.e., where you don't know
what you're doing). In such cases, Bucksbaum said, the molecule
"knows" its state, even if you don't. Scientists
can "ask" the system what works by repeatedly using
shaped pulses that "evolve" according to learning
algorithms that mimic evolutionary processes. The experimental
apparatus interrogates the atom or molecule, which provides
direct feedback to the laser. The laser system and the quantum
system work together through a trial-and-error approach to
find the pulse shape that produces the desired dynamics. This
is a new way to investigate the properties of many-body quantum
systems, and has promise for new chemicals, new methods for
quantum computing, or more efficient ways to produce and control
x rays.
Philip Bucksbaum is an alumnus of the
University of California, Berkeley, where he and Berkeley
Lab's new director, Steven Chu, worked together in Gene Commins'
research group. Over the next year, Bucksbaum will be on sabbatical
at the Stanford Linear Accelerator Center working on applications
of ultrafast quantum control in connection with the Linac
Coherent Light Source, the world's first x-ray free-electron
laser, scheduled to begin construction in fiscal year 2005.
More information on quantum control can be found at the Bucksbaum
Group's Web site.
Contact: Philip Bucksbaum, phb@umich.edu
ALS awards and
honors:
Saykally, Cavalleri
The ALS is pleased to acknowledge and
congratulate those in its orbit whose achievements have been
recognized through awards and honors.
 The
Department of Energy's Office of Science has presented the
Ernest Orlando Lawrence Award in Chemistry to ALS user Richard
Saykally (Chemical Sciences Division, Berkeley Lab, and Univ.
of California, Berkeley). The award acknowledges scientists
and engineers for their exceptional contributions to the development,
use, or control of nuclear energy. The Lawrence Award pays
tribute to Saykally's "invention of velocity modulation
spectroscopy of molecular ions; for the development of far
infrared vibration-rotation spectroscopy of radicals, clusters
and carbon chains; for the elucidation of the structure and
potential energy surfaces for water clusters; and for the
development and application of cavity ringdown laser spectroscopy
techniques."
Press release.
 ALS
user Andrea Cavalleri (Materials Sciences Division, Berkeley
Lab) recently returned from a trip to Stockholm, Sweden, where
he collected a European Young Investigator (EURYI) Award,
presented by the European Science Foundation. Cavalleri is
one of 25 recipients of this award, which comes with a grant
worth more than $1.5 million. The EURYI Awards seek to encourage
outstanding young researchers from anywhere in the world to
work in Europe and lead their own research team. This is the
first year that they have been presented. Cavalleri won for
his femtosecond time-resolved x-ray studies of critical phenomena
in strongly correlated materials. Press
release.
Users' Meeting:
Early registration
ends October 1
 REGISTRATION.
Friday, October 1, is the last day to take advantage of the
discounted early registration fees of $150.00 (regular) and
$60.00 (student). After that date, fees rise to $175.00 and
$75.00, respectively. Registering early also gives Berkeley
Lab's Conference Services time to process all the paperwork
necessary for visitor security passes at the entrance to the
Lab and prevents long lineups at the onsite registration desk.
Register
now.
AWARDS. The deadline
for award nominations recognizing outstanding user service,
scientific research, and innovative instrumentation at the
ALS has been extended to Thursday, October 7. The Users' Executive
Committee (UEC) invites ALS users and staff to submit nominations
for any or all of the awards:
- David A. Shirley Award for Outstanding
Scientific Achievement at the Advanced Light Source
- Klaus Halbach Award for Innovative
Instrumentation at the Advanced Light Source
- Tim Renner User Services Award
The nominations may be for an individual
or a group, and a brief rationale for the nomination(s) is
required. Past award winners, along with a representative
from the UEC and the ALS, will serve on the award selection
committee. To submit a nomination, go to the Award
Nominations Web page.
Agenda and workshops updates and accommodation
and general meeting information are all available on the 2004
ALS Users' Meeting
Web site.
Contact: alsum@lbl.gov
Report on Opportunities
in Terahertz
Science now available
 The
region of the electromagnetic spectrum from 0.3 to 20 THz
is a frontier area for research in physics, chemistry, biology,
medicine, and materials sciences. Sources of high-quality
radiation in this area have been scarce, but this gap has
recently begun to be filled by a wide range of new technologies.
New sources have led to new science in many areas, as scientists
become aware of the opportunities for research progress in
their fields using THz radiation. A workshop, jointly sponsored
by DOE, NSF, and NIH, was held in February 2004 to discuss
basic research problems that can be answered using THz radiation.
A report on the Workshop on Opportunities in Terahertz (THz)
Science is now available
online.
Contact: Michael Martin, MCMartin@lbl.gov |
