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In this issue:
Strong Currents Ahead
Science Today: X-Ray Diffraction and the Fight against Heart Disease
Fermi Research Alliance to Manage Fermilab

SLAC Today

Thursday - November 2, 2006

PEP-II, showing High-Energy (lower) and Low-Energy (upper) Rings. (Photo Courtesy of Peter Ginter. Click on image for larger version.)

Strong Currents Ahead

Midway through the four-month shutdown, the PEP-II rings are being primed for strong currents and big luminosity. By the end of the 2007 run, the rings will deliver 70 percent more luminosity to the BaBar experiment than during the record-breaking previous run.

To achieve these goals, crews are working to create high luminosity—as many collisions between electrons and positrons as possible. In the aftermath, fascinating and surprising physics emerges. The upgrade plan is taking two routes to ultimately increase luminosity 70 percent: adding more particles to a bunch and compressing particles closer together within a bunch.

In the first of three projects, the vacuum systems around the interaction region (where the electron and positron beams collide) are being improved to handle stronger beam currents. More current literally means more electrons (or positrons) in the beam. But when those multitudes of charged particles circle the PEP rings, they emit synchrotron radiation that can damage the vacuum system. Therefore, accelerator engineers are working on better controlling the radiation power hitting the vacuum systems. Read more...

(Daily Column - Science Today)

X-Ray Diffraction and
the Fight Against
Heart Disease

Three images of broken stents in the superficial femoral artery, which runs down the leg. (Image courtesy of C. Bonsignore.)

Endovascular stents—tubes inserted into arteries to keep them from constricting—manufactured from superelastic Nitinol represent a major component in the fight against heart disease. However, understanding the stress and strain distributions in such stents, which lead to deformation and fracture, is essential for their prolonged safe use in human arteries.

Nitinol, an alloy of nickel-titanium, can "remember" a previous shape and can recover strains as high as 10% by deformation (whereas most other metals can recover only about 0.5%). Deformation mechanisms of Nitinol are more complex than the conventional modes of plastic deformation in traditional alloys, and, as a result, the mechanical behavior of Nitinol under multiaxial conditions remains poorly understood.

Fermi Research Alliance to Manage Fermilab

Fermi Research Alliance, LLC, a partnership between the University of Chicago and Universities Research Association Inc., has been chosen by the U.S. Department of Energy to operate Fermi National Accelerator Laboratory, effective Jan. 1, 2007. The Alliance is a new corporation that was formed in response to the DOE's competition to manage Fermilab and is dedicated solely to the laboratory's management.

Fermilab has been operated for the Department of Energy by URA since the laboratory's inception in 1967, and scientists at the laboratory have made many crucial discoveries about the fundamental nature of matter and energy. The University of Chicago has managed the DOE's nearby Argonne National Laboratory since Argonne's founding in 1946. The DOE's Office of Science is the nation's major supporter of federally funded research in particle physics, and much of the past century's extraordinary progress in the understanding of the elementary structure of matter comes directly from DOE-funded research.

"Fermilab has for decades been the nation's center for research on the frontier of particle physics," said Robert J. Zimmer, President of the University of Chicago and Chairman of the FRA Board of Directors.  Read more...

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