babarpict

Aerial photo of SLAC

The 2 miles long LINAC (dominating the picture) became operational in 1966 producing 20GeV electrons. Beam energy was increased to 50GeV as part of the SLC project (1989). The PEP 30GeV storage ring started operation in 1980.

PEP-II is the first asymmetric electron-positron collider (also known as a Beauty Factory). It will collide a 9GeV electron beam with a 3.1GeV positron beam, running "on" the 10.58GeV Y(4S) resonance. It's design luminosity is 3x10³³.
Funded by $177 million from the U.S. Department of Energy, it was a joint construction project of SLAC, LBNL and LLNL. This dual-ring machine is an extensive upgrade of PEP. Construction began in 1994 and was completed in early July 1998. In the last week of July the first beam collisions were achieved. In February 1999 a peak luminosity of 5x10³² was achieved (72-hour average : 2x10³²).
In March/April 1999 the 1000 ton BABAR particle detector will be moved into position at the point where the two beams intersect (IR-2). BABAR will take beam data starting in early May 1999.

PEP-II plan and schematic

Inside the PEP-II tunnel

John Seeman and BABAR spokesman David Hitlin inside the PEP-II tunnel. Electrons circulate clockwise in an evacuated copper tube inside the lower ring of magnets, while the positron beam travels the other direction in the upper ring, through the yellow and blue magnets just behind them.