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PEP-II Breaks Record

It is a pleasure to report that PEP-II has not only returned to peak luminosity but also set a new all-time record of 10.028 x 1033 cm-2 s-1 on Monday, May 22. The same day also marked a new all-time high luminosity delivered by PEP-II (251.6 inverse picobarns) and recorded by BaBar (243.26 inverse picobarns) during a single shift. We continue to see high luminosity and are expecting to set additional records in the coming days, including delivered and recorded luminosity in a 24 hour period.

What's more, this week's peak luminosity was achieved with a substantially lower current in the Low Energy Ring (LER) than in last October’s record. Because LER current is directly related to overall luminosity, there is plenty of headroom for further improvement in the coming weeks. The backgrounds and running conditions also look very promising for the steady accumulation of data.

"The future looks bright thanks to recent upgrades and the hard work of the PEP-II and BaBar staff," said John Seeman, Head of the Accelerator Department.

Congratulations to the PEP-II team, which has overcome a number of difficult technical challenges while making excellent progress in understanding and correcting LER optics and radio frequency (rf) stability issues to achieve the new record. Congratulations as well to the BaBar run coordination team and shifters for their very professional and efficient operation of the detector.

—David MacFarlane
     SLAC Today, May 24, 2005

Image: Jochen Kaminski and Marin Simard display the recent luminosity record in the BaBar control room. (Click on image for larger version.)


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