1. EXAFS FROM HYDROGEN ATOMS IN WATER
(Contact: saykally@cchem.berkeley.edu)

In almost any circumstance where water plays a role, which includes most biological and environmental processes, as well as in many chemical reactions, hydrogen is ubiquitous. So, it stands to reason that locating the hydrogen atoms within molecules would be a high-priority task. It is unfortunate, therefore, that hydrogen with only one electron has been virtually impossible to detect with the conventional x-ray tools for measuring atomic structure (determining where the atoms are). But now a multi-institutional group (from the University of California, Berkeley, Lawrence Livermore National Laboratory, and the University of Washington) working at the ALS has demonstrated the ability to not only detect hydrogen by means of x-ray absorption but also measure its position in water-vapor molecules, a first step toward studying more complex samples. In this work, researchers report the first definitive measurements of the covalently bound hydrogen atom in water vapor by extended x-ray absorption fine structure (EXAFS).

Read the full story at http://www-als.lbl.gov/als/science/sci_archive/h_exafs.html.

Publication about this research: K.R.Wilson, J.G. Tobin, A.L. Ankudinov, J.J. Rehr, and R.J. Saykally, "Extended x-ray absorption fine structure from hydrogen atoms in water," Phys. Rev. Lett. 85(20), 4289 (2000).

2. SUPERBENDS INSTALLED, COMMISSIONING TO BEGIN TODAY
(Contact: JPHarkins@lbl.gov)

The ALS shutdown is into its second week and things are proceeding exceptionally well. In the first week, all three superbend magnets were installed and aligned, two days ahead of the planned schedule. The electrical and water connections have been completed, and the controls and monitoring systems have been tested. Final inspection of the magnets is scheduled for completion today, and then the critical commissioning period, in which the accelerator is adjusted to function with the new magnets, will begin. According to the plan, the linac and booster will be started up today, the storage ring systems will be checked out tomorrow morning, and the first attempts at storing beam in the storage ring will begin tomorrow afternoon. Accelerator physics teams will then work around the clock to get the accelerator ready for beam to users on October 4. Other items completed so far in this shutdown are the installation of an upgraded carbon filter box in the Beamline 5.0 front end, the removal of the Beamline 8.2 and 8.3 M1 mirrors for upgrades (to be reinstalled in late September), and the moving of the Sector 4 stairs and adjacent racks to make room for Beamlines 4.2 and 4.3. An upgrade of the gas cabinet ventilation system for Sectors 6 through 10 is in progress and will be completed by the end of the shutdown.

3. CAMBRIDGE PROF. HUMPHREYS GIVES SPECIAL LECTURE

What do a Monet painting, global warming, and gallium nitride have in common? They can all be tied together in an entertaining and informative talk by Colin Humphreys, Goldsmiths Professor of Materials Science at Cambridge University. Humphreys came to the Bay Area recently and was invited to give a special lecture at the ALS, where he was introduced by his Cambridge contemporary, ALS Division Deputy for Science Neville Smith. Humphreys' audience got a sense of his irrepressible and irreverent style through Neville's description of the distinguished professor's widely publicized research on the best way to eat spaghetti, which included an analysis of the "escape velocity" of spaghetti sauce.

The real meat of the talk, however, involved the materials science of light-emitting diodes (LEDs) and their associated ohmic contacts. According to Humphreys, light bulbs made from gallium nitride (GaN) LEDs consume 10% of the energy required by incandescent light bulbs and last 100 times as long. As a real-world example of the potential impact of this technology, Humphreys cited the city of Denver, which is in the process of putting GaN LEDs into all of its 13,000 traffic lights. The resulting power conservation, he said, would reduce emissions of carbon dioxide (a greenhouse gas implicated in global warming) by 17 million pounds each year, the equivalent of planting a 2000-acre forest in downtown Denver. As for the Monet reference--Humphreys opened the talk with an ironically beautiful depiction of the effects of pollution: a slide of a Monet painting of Waterloo Bridge in London seen through smog-diffused sunlight.

4. RAPID ACCESS FOR PROTEIN CRYSTALLOGRAPHY IN THE WORKS
(Contact: NVSmith@lbl.gov, GFKrebs@lbl.gov)

The ALS is considering a major overhaul of its procedure for reviewing and allocating beamtime for protein crystallography proposals. The present system is cumbersome and, in some cases, more than a year can elapse between submission of a proposal and receipt of beamtime. To get this interval down to a few months, a new rapid-access procedure is being developed. The new procedure would allow the submission of independent investigator proposals at any time rather than just twice a year. Once a month, the new proposals would be peer reviewed and scored, and those scoring highest would be allocated beamtime over the next few months. Proposals not receiving beamtime would remain active for three months. An email requesting input on this procedure has been sent to all Beamline 5.0.2 users. If there are no serious objections, the ALS hopes to implement the plan starting with allocations in 2002. The proposed plan can be seen online at http://www-als.lbl.gov/als/PXrapidsub/. Comments are welcome and can be sent to pxproposals@lbl.gov.

5. OPERATIONS UPDATE
(Contact: Lampo@lbl.gov)

For the user run of August 14 - 20, the beam reliability (time delivered/time scheduled) was 98%. Of the scheduled beam, 95% was delivered to completion without interruption. There were no significant outages. The ALS is currently in a planned shutdown for installations and maintenance. User operations are scheduled to resume at 12:00 a.m. on Thursday, October 4, 2001.

Long-term and weekly operations schedules are available on the Web (http://www-als.lbl.gov/als/accelinfo.html). Requests for special operations use of the "scrubbing" shift should be sent to Bruce Samuelson (BCSamuelson@lbl.gov, x4738) by 1:00 p.m. Friday. The Accelerator Status Hotline at (510) 486-6766 (ext. 6766 from Lab phones) features a recorded message giving up-to-date information on the operational status of the accelerator.

LBNL/PUB-848
Editors: lstamura@lbl.gov, alrobinson@lbl.gov, amgreiner@lbl.gov

This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC03-76SF00098.