SLAC Today is available online at:
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In this issue:
To the Edge of Melting
The Report Is In!
Andrei Linde to Present GLAST Public Lecture

SLAC Today

Friday - February 2, 2007

To time-stamp the arrival of each x-ray pulse, researchers use an electro-optic crystal (green) placed next to the electron beam (white) in the linear accelerator just before the beam produces x-rays. A laser (red) probes changes in the crystal to measure the exact time the beam passed by. The image was created by SLAC's Jean Charles Castagna. (Click on image for larger version.)

To the Edge of Melting

Picking a relatively simple system, SLAC scientists and their collaborators have used advanced tools to see the very first instants of change in a solid brought to the edge of melting. Their results appear in the February 2 issue of Science.

The experiment also demonstrated an important timing technique and was one of the last endeavors at the now-dismantled Sub-Picosecond Pulse Source (SPPS)—a proving ground for the more powerful Linac Coherent Light Source (LCLS). Being able to agitate a material with a laser pulse and then immediately measure its altered state with x-rays opens up an exciting world for researchers concerned with more complex systems that could prove helpful in fields including medicine and clean energy.

When a laser pulse strikes a semi-metal called bismuth, it disturbs the material's electrons. Because the energy of the laser is not enough to melt bismuth, the electrons relax back to their normal state in less than a nanosecond (one billionth of a second). But what happens in between?  Read more...

The Report Is In!

(Photo - Walter Leclerc)Three months ago, SLAC Today reported on the DOE Office of Independent Oversight (OIO) Environment, Safety, and Health evaluation of SLAC. Although SLAC management was briefed on the likely conclusions of the evaluation by the OIO team in November, the final report wasn't issued until this month.

The OIO evaluation reports 14 findings, four of which apply to either the DOE Stanford Site Office (SSO) or the Office of Science. Of the remaining ten findings, two of the most wide-ranging deal with how SLAC manages its requirements, such as DOE directives and regulations, and how we do our work planning and control. Many of the other findings were more program-specific, such as improving sub-contractor oversight and expanding the Stanford Synchrotron Radiation Laboratory Safety Assessment Document to include beamlines. Other findings related to strengthening our various site-wide environmental, safety, and health programs, including radiation protection, industrial hygiene, issues management, self-assessment, and incident investigation.

The receipt of the report starts a 60-day clock for SLAC to develop a corrective action plan (CAP) much like we did following the Type A accident investigation report on the arc-blast incident of October 2004. The CAP must be reviewed and approved by both the DOE Stanford Site Office (SSO) and the Office of Science (SC) at DOE headquarters within the 60-day period. As such, the lab must submit its draft CAP on February 16, 2007.

The Office of Assurance, under the leadership of recently hired Walter Leclerc, will oversee the development of the CAP. Under the direction of SLAC management, the office has created ten CAP teams, one for each of the ten SLAC-specific findings. Each team is staffed with ample representation from line management; in many cases line managers chair the teams. A core team will help ensure a consistent approach. SLAC has also hired an outside consulting firm, McCallum-Turner, which has a good deal of experience in OIO evaluations to help in the development of the CAP.  Read more...

Andrei Linde to Present GLAST Public Lecture

(Poster - GLAST)
Andrei Linde, a Stanford physics professor, will deliver a free public lecture, titled "The Origin and Fate of the Universe," at 8 p.m. on Monday, February 5, in Stanford's Arrillaga Alumni Center. His talk headlines the first international symposium focused on the scientific investigations enabled by the Gamma-ray Large Area Space Telescope (GLAST) mission, scheduled to launch in fall 2007 from Kennedy Space Center. From its eventual orbit 330 miles above Earth, the telescope will help scientists better understand the high-energy universe, including black holes, gamma-ray bursts, pulsars, cosmic rays, supernova remnants and relics left over from the Big Bang.

"Andre Linde is one of the principal architects of the inflationary theory of the origin and evolution of the universe," says GLAST Large Area Telescope (LAT) principal investigator Peter Michelson, a Stanford physics professor with an appointment at SLAC. "This is the leading theory that successfully accounts for the fluctuations seen in the cosmic microwave background. These fluctuations in the early universe lead to the structures, stars and galaxies that we observe today."

The space telescope will probe extreme environments and cataclysmic events in the universe with a 3,000-kilogram primary instrument, the LAT, which will detect gamma rays up to 100 million times more energetic than the average dental X-ray. GLAST also will sport a smaller instrument, called the GLAST burst monitor, to detect lower-energy gamma-ray eruptions.

"We at Stanford are delighted to host the scientists from all around the world who have worked so hard on GLAST," says SLAC and physics Professor Roger Blandford, director of the Kavli Institute for Particle Astrophysics and Cosmology. "Everyone is excited about the discoveries it should make."

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