Abstract
The Tevatron in Collider Run II (2001-present) is operating with 6 times more bunches, many times higher beam intensities and luminosities than in Run I (1992-1995). Electromagnetic long-range and head-on interactions of high intensity proton and antiproton beams have been significant sources of beam loss and lifetime limitations. We present observations of the beam-beam phenomena in the Tevatron and results of relevant beam studies. We analyze the data and various methods employed in operations, predict the performance for planned luminosity upgrades, and discuss ways to improve it.
Highlights
COLLIDER RUN II LUMINOSITY AND BEAM PARAMETERRun II of the Tevatron proton-antiproton collider began in March 2001
In parallel to the collider operation, we have started a luminosity upgrade project which should lead to peak luminosities of about 2:7 1032 cmÿ2 sÿ1 and total integrated luminosity of 4:4–8:5 fbÿ1 through 2009
Proton bunch intensities and emittances vary from bunch to bunch by less than 5%, while antiproton bunch intensities vary by a factor of 3, and emittances by a factor of 1.5
Summary
Run II of the Tevatron proton-antiproton collider began in March 2001. Compared to run I, the beam energy was increased from 900 to 980 GeV and the number of bunches was increased from 6 to 36 in each beam, in order to increase luminosity many times above the run I record peak luminosity of 0:25 1032 cmÿ sÿ1. Like the few percent loss of protons and antiprotons during the halo removal process Such scraping greatly reduces background event rates in both detectors and improves their data-taking efficiency. Beam-beam effects in the Tevatron account for a 20%–27% loss in the luminosity integral due to (a) 10%–12% particle loss before the start of collisions and (b) 10%–15% reduction in the luminosity lifetime. This loss is significant and it may be even larger after the luminosity upgrades, requiring continued systematic attention. This paper presents observations and analysis valuable for future Tevatron operation
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