| Paper |
Title |
Page |
| TUPAS033 |
Field Fluctuation and Beam Screen Vibration Measurements in the LHC Magnets
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1724 |
| |
- V. D. Shiltsev
Fermilab, Batavia, Illinois
- T. Kroyer, R. de Maria
CERN, Geneva
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We present experimental methods and results of magnetic field fluctuation and beam screen vibration measurements in the LHC magnets. These noises can lead to an emittance grwoth in proton beams if they have spectral components at the betatron lines. A preliminary estimates of the effects are given.
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| THPAN072 |
A Concept for the LHC Luminosity Upgrade Based on Strong Beta* Reduction Combined with a Minimized Geometrical Luminosity Loss Factor
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3387 |
| |
- E. Todesco, R. W. Assmann, J.-P. Koutchouk, E. Metral, G. Sterbini, F. Zimmermann, R. de Maria
CERN, Geneva
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A significant increase of the LHC beam current touches physics limits as collective effects, electron-cloud, heat load, collimation and machine protection. We propose an upgrade scheme mainly based on a stronger focusing, with a beta* of 10 cm, requiring a triplet quadrupole aperture of around 130 mm. The performance is further improved if the triplet is based on the Nb3Sn technology. In the present baseline, this beta* reduction provides a negligible luminosity increase: this approach requires a drastic action to minimize the crossing angle, while the beam separation at the long-range encounters has to be increased. This is provided by an early separation scheme made of small dipoles inside the detectors. Optionally, a small angle crab cavity scheme may totally suppress the residual crossing angle. The quadrupole aperture is calculated to allow a larger gap for the collimator, suppressing their impedance limitation. This concept offers high performance while significantly reducing the risks associated to a beam current increase; it opens as well new issues that deserve further studies, such as the dipole integration in the detector, and the correction of the triplet aberrations.
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