Paper | Title | Page |
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TPPP026 | Bunch-Length Measurements in PEP-II | 1934 |
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Funding: Supported by U.S. Department of Energy contract DE-AC03-76SF00515. We measured the lengths of colliding e+e- bunches in the PEP-II B Factory at SLAC using various techniques. First, at several RF voltages and with both single-bunch and multibunch beams, a synchroscan streak camera measured synchrotron emission through a narrow blue filter. With 3.8 MV of RF, the length of a single positron bunch was 12 mm at low current, rising to 13 mm at 1.5 mA and 14.8 mm at 3 mA. The electrons measured 12.2 mm with little current dependence. Both are longer than the expected low-current value of 10 mm (e+) and 11 mm (e-), derived from the energy spread and the measured synchrotron tune. We also determined the length from measurements between 2 and 13 GHz of the bunch spectrum on a BPM button. After correcting for the frequency dependence of cable attenuation, we then fit the measured spectrum to that of a Gaussian bunch. With 3.8 MV, the positrons measurement gave 13.2 mm at 1.5 mA/bunch in a full ring, in agreement with the streak camera, but we found 11.4 mm for the electrons at 16.7 MV and 1 mA/bunch, lower than the streak measurement. |
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TPPP035 | Performance of the PEP-II B-Factory Collider at SLAC | 2369 |
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Funding: Work supported by DOE contract DE-AC02-76SF00515. For the PEP-II Operation Staff: PEP-II is an asymmetric e+e- collider operating at the Upsilon 4S and has recently set several performance records. The luminosity has reached 9.2 x 1033/cm2/s. PEP-II has delivered an integrated luminosity of 710/pb in one day. It operates in continuous injection mode for both beams boosting the integrated luminosity. The peak positron current has reached 2.55 A in 1588 bunches. The total integrated luminosity since turn on in 1999 has reached 256/fb. This paper reviews the present performance issues of PEP-II and also the planned increase of luminosity in the near future to over 2 x 1034/cm2/s. Upgrade details and plans are discussed. |