Experimental Test of Self-Shielding in VUV Photodissociation of CO
One way to test models of the solar system's formation is to compare the isotopic abundances of the elements found in its constituent bodies. A case in point is oxygen with three stable isotopes dominated by oxygen-16, with minute fractions of oxygen-17 and oxygen-18. Primitive objects whose formation predates the Earth's, such as the calcium-aluminum-rich inclusions in the Allende meteorite, have relatively higher fractions of the two heavier isotopes than does the Earth’s crust. Among the numerous explanations that have been proposed is the notion that chemical processes within the early solar nebula gave rise to the oxygen ratios, a leading candidate being a process called isotope self-shielding. But researchers from the University of California, San Diego, and Berkeley Lab have now shown that photodissociation of carbon monoxide (CO) caused by vacuum-ultraviolet (VUV) light from the early sun could generate reservoirs of the heavier isotopes in the solar nebula without the help of self-shielding. Read more...
Publication about this research: S. Chakraborty, M. Ahmed, T.L. Jackson, and M.H. Thiemens, "Experimental test of self-shielding in vacuum ultraviolet photodissociation of CO," Science 321, 1328 (2008).
Self-Assembly of Polymer Nano-Elements on Sapphire
Self-assembly of polymers promises to vastly improve the properties and manufacturing processes of nanostructured materials, since self-assembly is highly parallel, quite versatile, and easy to implement. Especially promising are novel compounds known as block copolymers, formed by two chemically different polymers that are linked together. Guided patterned arrays have been produced using electron-beam lithographic techniques or nano-imprint lithography, but these methods are painstaking, and they have not yet been able to produce perfect surfaces over large areas. Recently, a group of researchers used faceted surfaces of commercially available sapphire wafers to guide the self-assembly of block copolymer microdomains. Grazing-incidence small-angle x-ray scattering (GISAXS) at ALS Beamline 7.3.3 verified the arrays' quasi long-range crystalline order over arbitrarily large wafer surfaces. It's expected that this new method of producing highly ordered macroscopic arrays of nanoscopic elements will revolutionize the microelectronic and storage industries and perhaps others, such as photovoltaics. Read more...
Publication about this research: S. Park, D.H. Lee, J. Xu, B. Kim, S.W. Hong, U. Jeong, T. Xu, and T.P. Russell, "Macroscopic 10-terabit-per-square-inch arrays from block copolymers with lateral order," Science 323, 1030 (2009).
New Responsibilities for Falcone, Schoenlein, Oddone
ALS Division Director Roger Falcone has been appointed by Berkeley Lab's Interim Director Paul Alivisatos to serve as Associate Laboratory Director for Photon Sciences. In this position, Roger will continue to serve as ALS director, leading efforts to renew the ALS while working to secure the Next Generation Light Source at Berkeley Lab. The Next Generation Light Source has the potential to revolutionize energy science research and is a critical project for the future of Berkeley Lab. Alivisatos also appointed Environmental Energy Technology Division Director Arun Majumdar to serve as Associate Laboratory Director for Energy and Environment. In a videotaped announcement, Alivisatos said: "These are exciting times for Berkeley Lab. Together, we are pursuing new large-scale science and technology initiatives for energy and environment, topics that are more relevant than ever to the health and prosperity of our nation and the planet... Please join me in thanking Roger and Arun for assuming these additional responsibilities, which are effective immediately. Both are outstanding scientists and have served this Lab with distinction. The Lab will be stronger for their strength and vision."
Also this month, Roger announced that Bob Schoenlein is joining the ALS as Deputy Director for Science. Bob is a scientist with the Materials Sciences Division at Berkeley Lab and is well known to many at the ALS as the developer of Beamline 6, our ultrafast x-ray facility, and an expert in condensed-phase physics. He has worked on projects ranging from the dynamics of biomolecules to the understanding of complex oxides and with photons ranging from the infrared to x rays. He is an internationally recognized leader in optical sciences, was educated at MIT, and has been at Berkeley Lab for 20 years. In a transitional period over the next year, Bob will be working together with ALS Science Advisor Janos Kirz.
Finally, Paul Alivisatos has asked ALS Special Assistant for Strategic Initiatives, Pat Oddone, to assist him and his staff as he makes the transition to Interim Laboratory Director. Pat is now stationed in Building 50A, and it is expected that Pat's stay will last a minimum of six to nine months. You might still see her around the ALS from time to time as she continues to be involved in ALS initiatives and Next Generation Light Source planning.
Positive Report from DOE Health, Safety, and Security Audit
As you all know, ALS was one of the divisions selected for the recently concluded Department of Energy (DOE) Health, Safety, and Security (HSS) audit. This was the most comprehensive safety inspection Berkeley Lab has undergone in more than a decade. At the ALS alone, more than 40 people were observed performing work, auditors sat in on several of our safety meetings, and dozens of documents were reviewed during the three weeks that they were here.
We are very happy to report that HSS found all of our Integrated Safety Management (ISM) Core Functions to be "effectively performed," the top rating. This is an extremely positive result for our division and we should be very proud of this accomplishment. We think we've all come to realize the importance of safety, both as an ethical and legal imperative, and for its impact to our scientific mission. Safety is now an important part of generating confidence on the part of our funders so reports such as this play a big role in our ability to continue to succeed.
One comment in the report is especially meaningful: "Division management and staff displayed their commitment to teamwork and safety in the development and implementation of hazard controls...." We know how hard all of you have worked this last year and we have seen your dedication and teamwork, so it is very gratifying to see that this was also recognized by HSS. Your openness and willingness to learn from this review went a long way towards achieving this measure of recognition.
However, we should recognize that we still have many areas that we can and need to improve upon. The appendices to the report list many items that they found during their time here and we all identified many more as a result of this process. This report, however, clearly shows that we've accomplished much and are on the right track. Many thanks again to all of you.
UEC Corner: Save the Dates for 2009 ALS Users' Meeting
From meeting co-chairs David Osborn and Yayoi Takamura:
Make plans to attend the 2009 ALS Users' Meeting, Thursday, October 15, through Saturday, October 17, 2009. This year's meeting will be hosted jointly with the Molecular Foundry and will have a primary focus on research to further the United States' and the world's energy agenda. The meeting will have plenary talks, workshops, a joint poster session, and vendor exhibits. If you would like to organize a workshop for the 2009 Users' Meeting, please contact
, this year's meeting co-chairs. Check the meeting Web site periodically for the latest information, as it becomes available.
For the user runs from January 21 to February 15, 2009, the beam reliability (time delivered/time scheduled) was 95.9%. Of the scheduled beam, 88.7% was delivered to completion. This includes the first week of user operations in top-off mode. There were no significant interruptions.
For the user runs from February 18 to March 15, 2009, the beam reliability was 96.0%. Of the scheduled beam, 89.7% was delivered to completion. This includes two weeks of two-bunch operation from March 4-15. There were no significant interruptions.
Questions about beam reliability should be sent to
. Requests for special operations use of the "scrubbing" shift should be sent to Rick Bloemhard (
Long-term and weekly operations schedules are available here. View the ring status in real time here.
*Time delivered/time scheduled
**Percent of scheduled beam delivered without interruption