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Director’s Update: High Praise for the ALS in BES Triennial Review Report
I would like to share with you some of the observations. Reviewers noted that the ALS has made significant improvements for the user community, including a web-based proposal system described as being transparent and fair. They also commended ALS Safety Program Manager Jim Floyd’s collaborative style of working with users to implement pragmatic safety measures. There was praise for the progress made toward top-off operation, as well as for several instrument achievements, including the new EPU Beamline 11.0.1 and the steps taken toward the PEEM3 microscope; superbend Beamline 12.3.2, which extended the energy range for white-beam x-ray Laue microdiffraction and provided enhanced strain sensitivity; the progress on Beamline 4.0.3 (MERLIN), including an aperiodic undulator for harmonic rejection; and the move of the ultrafast Finally, reviewers were impressed by the strong interactions between the ALS and both the Scientific Advisory Committee (SAC) and the Users’ Executive Committee (UEC). They also commented favorably on the ALS Strategic Plan and pointed out that the ALS has taken the lead in establishing a graduate student and post-doc support program, vital to developing a pipeline for future beamline and accelerator scientists. Other than our well-known staffing shortages, no major shortcomings were identified in the review. Dr. Montano’s letter accompanying the report summary concludes by “commending the ALS on continuing its outstanding scientific output and instrument development,” a view I heartily share. This was a gratifying review, a testament to our collective efforts at the ALS. I thank everyone for a job well done. |
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Slow Dynamics of Orbital Domains in a Manganite At the ALS, an international team of researchers has used low-energy coherent x rays to extract new knowledge about the correlated motion of groups of self-assembled, outer-lying electrons in the extremely complex electronic system found in manganites. The manganite family of materials has puzzled physicists for years by defying standard models for the motion of electrons in crystals. By controlling the properties of the incident x rays, the researchers were able to map the complexity of a “half-doped” manganite into a far-field speckle diffraction pattern to study the manganite’s domain dynamics. Their results suggest that the material undergoes a transition characterized by the competition between a pinned orbital domain topology that remains static and mobile domain boundaries that exhibit slow, temporal fluctuations. Read more…
Publication about this research: J.J. Turner, K.J. Thomas, J.P. Hill, M.A. Pfeifer, K. Chesnel, Y. Tomioka, Y. Tokura, and S.D. Kevan, “Orbital domain dynamics in a doped manganite,” New J. Phys. 10, 053023 (2008). |
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Looking at Transistor Gate Oxide Formation In Real Time The oxide gate layer is critical to every transistor, and present-day layer thickness is in the 10–20 Å range (1–2 nm). However, little information exists on the oxidation process at this thickness. Available results are either for thicker layers grown under high-pressure conditions or for only the first couple of monolayers studied under high-vacuum conditions. Now, for the first time, a group of researchers has obtained real-time oxidation results for this elusive range. Using the ambient-pressure x-ray photoelectron spectroscopy (APXPS) endstation at Beamline 9.3.2, they examined oxidation of Si(100) at pressures up to 1 torr and temperatures up to 450 ºC. The Si 2p chemical shifts allowed determination of oxide thickness as a function of time with a precision of 1–2 Å. The initial oxidation rate was very high (up to ~234 Å/h). Then, after an initial oxide thickness of 6–22 Å was formed, it decreased markedly (~1.5–4.0Å/h). Neither rate regimes can be explained by the standard Deal-Grove (D-G) model for Si oxidation. These results are a significant step toward developing other models for this critical thickness regime. Read more…
Publications about this research: Y. Enta, B.S. Mun, M. Rossi, P.N. Ross, Jr., Z. Hussain, C.S. Fadley, K.-S. Lee, and S.-K. Kim, “Real-time observation of the dry oxidation of the Si(100) surface with ambient pressure x-ray photoelectron spectroscopy,” Appl. Phys. Lett. 92, 012110 (2008); M. Rossi, B.S. Mun, Y. Enta, C.S. Fadley, K.S. Lee, S.-K. Kim, H.-J. Shin, Z. Hussain, and P.N. Ross, Jr., “In situ observation of wet oxidation kinetics on Si(100) via ambient pressure x-ray photoemission spectroscopy,” J. Appl. Phys. 103, 044104 (2008). |
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Facilities Feature: A Swiss Army Knife with a 4-Micron Blade This is how beamline scientist Matthew Marcus thinks of Beamline 10.3.2, a hard x-ray microprobe with an energy range from 2.5 keV (sulfur K-edge) to 17 keV, producing a monochromatic beam focused to a spot size on the sample of 4 to 16 µm. It’s an apt metaphor for this versatile beamline as it combines three techniques that can be used in succession on the same sample. Experimental techniques include micro x-ray fluorescence (µXRF), which probes chemical composition; x-ray absorption spectroscopy (µXAS), which probes chemical state and environment of a specific element; and x-ray diffraction (µXRD), which examines crystal structure of major phases at a point.
Sirine Fakra and Matthew Marcus, ALS Beamline 10.3.2 scientists. Many research teams have been benefiting from 10.3.2’s versatility. Exciting findings in the areas of environmental remediation and solar cell engineering have emanated from two groups in particular. Manceau et al. have discovered a new form of copper in the rhizosphere. The team imaged the distribution of copper at the soil–root interface by µXRF and identified the new copper species as metallic nanoparticles by micro extended x-ray absorption fine-structure (µEXAFS) spectroscopy and µXRD. Promoting the formation of copper metal in the rhizosphere could be a highly efficient method of remediating copper contamination. Click here to view a highlight on this research. Buonassisi et al. have been investigating the distribution of impurities in silicon solar cell material. The researchers use a combination of µXRF and µXAS techniques to study the distribution, chemical state, and electron-hole recombination activity of metal clusters in mc-Si. This research will provide valuable information on how to manipulate impurities and reduce their detrimental impact on efficiency, and is a promising path to cheaper solar energy. Click here to view a highlight on this research. Upgrades planned for the beamline include replacement of Kirkpatrick-Baez (KB) mirrors and benders to attain submicron spot size; installation of “QuickXAS,” allowing acquisition of XAS spectra in under a minute; installation of a low-energy-capable monochromator to increase energy range and get to Al and, perhaps, Mg K-edges; and full spectrum/pixel µXRF mapping. |
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UEC Corner: Users’ Meeting Approaches; Contact Your Local Representative
Contact Your Local Representative. I would also like to encourage all of you to “get involved.” The current funding situation at the national laboratories, which includes the ALS, is extremely poor. We already have to cope with reductions in staff and operating time, which affect our research programs. It is important and necessary that we make our concerns heard in Washington. Please contact your local representatives and let them know how the budget situation affects your research and the education of your students. Information and help regarding this issue can be found at http://www.aps.org/policy/tools/index.cfm |
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2008 ALS Users’ Meeting: Call for Abstracts and Meeting Information Contact: alsum@lbl.gov General information, meeting deadlines, and online registration for this year’s ALS Users’ Meeting, to be held at Berkeley Lab on October 13–15, 2008, will be posted shortly on the Users’ Meeting Web site. The early registration deadline is Friday, September 19. Click here for local hotel accommodation information for meeting participants.
Abstracts Submission. The deadline for abstract submissions for oral presentations during the ALS Scientific Highlights session is Friday, August 15. Submissions for the oral presentations and poster sessions, including the student poster competition, can be entered online. Workshops. This year, ten workshops will follow the end of the formal Users’ Meeting program beginning Tuesday morning (October 14) and continuing through the morning of Wednesday, October 15. Organizer contact information and several workshop topics are available on the Users’ Meeting Workshops Web page. |
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General User Proposal Scores Posted Online. The general user beam time allocation process for the running period from July through December 2008 is complete for the general sciences. The number of eight-hour shifts requested was 7152, of which 3583 shifts (50%) were allocated to general users. For more detailed results, including beamline score distributions and cutoff scores, go to General User Proposal Scores: General Sciences. Beam-time requests for general user experiments are reviewed twice each year. All proposals first undergo peer review, after which a Proposal Study Panel (PSP) also evaluates each proposal. This process is the basis for granting beam time. The PSP is made up of ten scientists from a variety of synchrotron scientific disciplines. There is a separate PSP that reviews the crystallography proposals six times each year. More information on the PSP and the general user proposal review process is available on the General User Proposals Web page. July 15 Deadline for General User Proposal Submissions. The User Services Office is accepting general user proposals from scientists who wish to conduct research in the general sciences at the ALS during the running period from January through June 2009. The deadline is July 15, 2008. (This deadline does not apply to protein crystallography proposals, which have a separate process and schedule.) To submit a new proposal, fill out the ALS General User Proposal and Request for Beam Time form. For further information on proposals, go to the General User Proposals Web page. Bulletin Board Guest House Construction Site and Altered Pedestrian Routes. Construction is now underway at the Guest House site. For your safety, it is requested that you follow new pedestrian routes. For those going down the stairs next to Building 2 from Buildings 6, 80, etc., please turn left on the new pedestrian path to access the cafeteria. For those exiting Building 2 on the ground floor, you will notice that you are now directed to the right. Please observe this direction and use the new crosswalk, and walk inside the new handrails. Trucks and equipment will be entering and exiting from both ends of the construction site. Please exercise extra caution when walking near the site. The ALS Experiences Another Safe and Successful Shutdown. Another safe and successful shutdown has been completed at the ALS. The second of four phases of a seismic retrofit of the ALS dome was done as well as a variety of technical projects. These included the annual replacement of the superbend magnet cold heads, installation of apertures in beamline front ends to ready for top-off mode injection, interlock installations and testing for top off, as well as many smaller beamline projects. User operations resumed on June 12.
ALS Infrared Beamlines Unveils New Web Page. This useful and all-purpose Web site has tools for current users, publications lists, news and information links, and more. To view, go to http://infrared.als.lbl.gov. For the user runs from May 12 to June 16: Beam reliability*: 94.0%; Completion**: 85.8%. This period includes the scheduled shutdown for maintenance, installation, and upgrade, which began on May 12 and went through June 11; only the user run from June 12–16 is reflected in the data above. There were no significant interruptions. Questions about beam reliability should be sent to David Richardson. Requests for special operations use of the “scrubbing” shift should be sent to Rick Bloemhard (ALS-CR@lbl.gov, x4738) by 1:00 p.m. Friday. *Time delivered/time scheduled |
Pedro Montano, BES Scientific User Facilities Division Director, has sent me a summary of the report from the triennial DOE Basic Energy Sciences review of the ALS that was held last March, and I am extremely proud of the results. To quote the opening paragraph, “The ALS scientific output continues to excel with an exceptional percentage of publications in the ‘high impact’ category. This reflects positively on its world-class beamline capabilities and outstanding scientific staff.” This is high praise, indeed, only made possible by the contributions of all members of the ALS staff and users working together.
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Users’ Meeting Approaches. The 2008 Users’ Meeting is fast approaching (October 13–15). The poster session will again be held in conjunction with the Molecular Foundry. Another important item on the program agenda are the awards that are given out annually by the ALS Users’ Executive Committee. You will have the opportunity to nominate a person or a group for the David A. Shirley Award for Outstanding Scientific Achievement at the ALS, the Klaus Halbach Award for Innovative Instrumentation at the ALS, and the Tim Renner User Services Award for Outstanding Support to the ALS User Community. The deadline for nominations will be set well before the start of the meeting to give the committee the opportunity to carefully deliberate and ask for advice from external experts if needed. In addition to the nominations submitted for the Shirley Award, we will also review the ALS publication database for high-impact publications that resulted from research performed at the ALS over the past two years. (For information on Users Meeting logistics, see “ALS Users’ Meeting: Call for Abstracts and Meeting Information,” below.)