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In this issue:
Nobel Prize in Physics Awarded
Symmetry Explains It in 60 Seconds: Cherenkov Light
Safety at a Glance: The ES&H Dashboard

SLAC Today

Tuesday - October 6, 2009

Nobel Prize in Physics Awarded

Bell Labs researchers Willard Boyle (left) and George Smith (right) with the charge-coupled device. Photo taken in 1974. (Photo: Alcatel-Lucent/Bell Labs.)

The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Physics for 2009 with one half of the $1.4 million to:

Charles Kao of Standard Telecommunication Laboratories, Harlow, UK, and Chinese University of Hong Kong, "for groundbreaking achievements concerning the transmission of light in fibers for optical communication"

and the other half jointly to:

Willard Boyle and George Smith of Bell Laboratories, Murray Hill, New Jersey, "for the invention of an imaging semiconductor circuit – the CCD sensor." 

Read more in Physics Today...

See also Optics Pioneers Scoop Nobel Prize from Physicsworld and 'Masters of Light' Win Nobel Prize from Physorg.

Symmetry Explains It in 60 Seconds: Cherenkov Light

(Image: Symmetry Magazine.)

Cherenkov light appears when a charged particle travels through matter faster than light can. This effect is the optical equivalent of a sonic boom, which occurs, for example, when a jet travels faster than the speed of sound.

But how can a particle go faster than light without violating the laws of physics? The speed of light in a vacuum is the ultimate speed limit: 300,000,000 meters per second. It's thought that nothing can travel faster.

However, light slows down when it goes through water, glass, and other transparent materials—in some cases by more than 25 percent. Hence a particle can slip through material faster than light does, while at the same time staying below the speed of light in a vacuum.

When this happens, a particle emits bluish Cherenkov light, which spreads out behind it in a hollow cone that is shaped like the cone of a sonic boom. This light gives the water surrounding a nuclear reactor core its distinctive blue glow.

Scientists build telescopes to gather Cherenkov light emitted by cosmic-ray and gamma-ray showers in the Earth's atmosphere. Neutrino physicists embed hundreds of light-sensitive detectors in large volumes of water and ice to record Cherenkov light from muons and electrons, which emerge when neutrinos crash into atoms. The Cherenkov light recorded with such devices helps scientists identify particles and determine their energies.

SLAC Safety Notes

Safety at a Glance:
The ES&H Dashboard

SLAC's Environment, Safety and Health Division has developed a new tool so that lab staff can quickly gauge the health of SLAC ES&H performance: the ES&H Dashboard.

From left: Madhu Swaminathan , Kevin Purcel, Scott Mangold and Steve Williams were all key to creating and launching the dashboard. (Photo by Brad Plummer.)

Launched in mid-March, the dashboard can be accessed by all SLAC employees from the top right corner of the ES&H home page. The schematic design allows users to access key ES&H-related metrics for the lab and zoom down to each directorate's specific information quickly and easily.

"The dashboard displays lab-wide information with drilldown capabilities," said ES&H Director Craig Ferguson. "It was built to present key ES&H performance information with easy access, so that managers and staff would not have to spend time accessing several system interfaces."

The dashboard model is often used in industry and government to provide transparency and current information on critical programs, Ferguson noted. Kymberly Snead of the ES&H Division led the effort to gather customer input and review best practices by looking at performance metric systems at several Department of Energy labs, Stanford University and several vendors to determine the most feasible solution for SLAC.

"A manager can quickly get answers for himself," said Stephen Williams, of the Director's Office, who helped to make the project happen. "The dashboard is convenient, customized, and creates a sense of responsibility directly to the person."

ES&H plans to continue the dashboard and make it even more customizable in the future. If you have feedback on how to improve the dashboard please contact Kymberly Snead (x4298).


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