Paper |
Title |
Page |
TUPZ023 |
Observation of Bunch to Bunch Differences due to Beam-beam Effects |
1855 |
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- G. Papotti, R. Alemany-Fernandez, R. Giachino, W. Herr, T. Pieloni, M. Schaumann, G. Trad
CERN, Geneva, Switzerland
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Due to the bunch filling schemes in the LHC the bunches experience a very different collision schedule and therefore different beam-beam effects. These differences and the effect on the performance have been observed and compared with the expectations. Possible limitations due to these effects are discussed.
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TUPZ025 |
Experience with Offset Collisions in the LHC |
1858 |
|
- G. Papotti, R. Alemany-Fernandez, F. Follin, R. Giachino, W. Herr, T. Pieloni, M. Schaumann
CERN, Geneva, Switzerland
- R. Calaga, R. Miyamoto
BNL, Upton, Long Island, New York, USA
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To keep the luminosity under control, some experiments require the adjustment of the luminosity during a fill, so-called luminosity leveling. One option is the separate the beams transversely and adjust the separation to the desired collision rate. The results from controlled experiments are reported and interpreted. The feasibility of this method for ultimate luminosities is discussed.
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WEPC081 |
Beam-Beam Induced Orbit Effects at LHC |
2208 |
|
- M. Schaumann, R. Alemany-Fernandez
CERN, Geneva, Switzerland
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For high bunch intensities the beam-beam force is strong enough to expect orbit effects if the two beams do not collide head-on but with a crossing angle or with a given offset. As a consequence the closed orbit changes. The closed orbit of an unperturbed machine with respect to a machine where the beam-beam force becomes more and more important has been studied and the results are presented in this paper.
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WEODA01 |
Observations of Beam-beam Effects at High Intensities in the LHC |
1936 |
|
- W. Herr, R. Alemany-Fernandez, R. Giachino, G. Papotti, T. Pieloni
CERN, Geneva, Switzerland
- R. Calaga
BNL, Upton, Long Island, New York, USA
- E. Laface
ESS, Lund, Sweden
- M. Schaumann
RWTH, Aachen, Germany
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First observations with colliding beams in the LHC with bunch intensities close to nominal and above are reported. In 2010 the LHC initially operated with few bunches spaced around the circumference. Beam-beam tune shifts exceeding significantly the design value have been observed. In a later stage crossing angles were introduced around the experiments to allow the collisions of bunch trains. We report the first experience with head-on as well as long range interactions of high intensity bunches and discuss the possible performance reach.
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Slides WEODA01 [0.409 MB]
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