| Paper | Title | Page |
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| MOPEC001 | Numerical Analysis of Machine Background in the LHCb Experiment for the Early and Nominal Operation of LHC | 450 |
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We consider the formation of machine background induced by proton losses in the long straight section of the LHCb experiment at LHC. Both sources showering from the tertiary collimators located in the LHCb insertion region as well as local beam-gas interaction are taken into account. We present the procedure for, and results of, numerical studies of such background for various conditions. The expected impact on the experiment and signal characteristics are also discussed. |
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| TUPEB072 | Beam-gas Loss Rates in the LHC | 1686 |
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We report on first observations and detailed simulations of beam gas rates in the LHC. For the simulations, a comprehensive tool has been set up to simulate in a few hours the expected beam gas losses when pressure maps, collimator settings, and/or beam optics changes. The simulation includes both elastic and inelastic scattering, with subsequent multiturn tracking of proton residues. This provides amongst others a more realistic collimator loss distributions from elastic interactions than what was previously available. |
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| TUPEB073 | Dependence of Background Rates on Beam Separation in the LHC | 1689 |
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Background and loss rates vary when beams are brought into collisions in the LHC and when the beam separation is varied during luminosity scans. We report on the first observations in the early LHC operation. The observed effects are analyzed and compared with models and simulation. |
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| TUPEB034 | Interaction Region Design for a Ring Ring Version of the LHeC Study | 1596 |
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The LHeC aims at colliding hadron-lepton beams with center of mass energies in the TeV scale. For this purpose the existing LHC storage ring is extended by a high energy electron accelerator in the energy range of 60 to 140 GeV. The electron beam will be accelerated and stored in a LEP like storage ring in the LHC tunnel. In this paper we present the layout of the interaction region which has to deliver at the same time well matched beam optics and an efficient separation of the electron and proton beams. In general the large momentum difference of the two colliding beams provides a very elegant way to solve this problem: A focusing scheme that leads to the required beam sizes of the electrons and protons is combined with an early but gentle beam separation to avoid parasitic beam encounters and still keep the synchrotron radiation level in the IR within reasonable limits. We present in this paper two versions of this concept: A high luminosity layout where the mini beta magnets are embedded into the detector design as well as an IR design that is optimised for maximum acceptance of the particle detector. |
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| TUPEB037 | Interaction-Region Design Options for a Linac-Ring LHeC | 1605 |
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In a linac-ring electron-proton collider based on the LHC ("LR-LHeC"), the final focusing quadrupoles for the electron beam can be installed far from the collision point, as far away as the proton final triplet (e.g. 23 m) if not further, thanks to the small electron-beam emittance. The inner free space could either be fully donated to the particle-physics detector, or accommodate "slim" dipole magnets providing head-on collisions of electron and proton bunches. We present example layouts for either scenario considering electron beam energies of 60 and 140 GeV, and we discuss the optics for both proton and electron beams, the implied minimum beam-pipe dimensions, possible design parameters of the innermost proton and electron magnets, the corresponding detector acceptance, the synchrotron radiation power and its possible shielding or deflection, constraints from long-range beam-beam interactions as well as from the LHC proton-proton collision points and from the rest of the LHC ring, the passage of the second proton beam, and the minimum beta* for the colliding protons. |
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| TUPD061 | Simulations of the LHC Collimation System | 2066 |
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The collimation system of the LHC will be critical to its success, as the halo of high energy (7 TeV) particles must be removed in such a way that they do not deposit energy in the superconducting magnets which would quench them, or showers in the experiments. We study the properties of the LHC collimation system as predicted by the Merlin and Sixtrack/K2 simulation packages, and compare their predictions for efficiency and halo production, and the pattern of beam losses. The sophisticated system includes many collimators, serving different purposes. Both programs include energy loss and multiple Coulomb scattering as well as losses through nuclear scattering. The MERLIN code also includes the effects of wakefields. We compare the results and draw conclusions on the performance that can be achieved. |
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| WEPE019 | The CLIC Post-Collision Line | 3386 |
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The 1.5TeV CLIC beams, with a total power of 14MW per beam, are disrupted at the interaction point due to the very strong beam-beam effect. As a result, some 3.5MW reach the main dump in form of beamstrahlung photons. About 0.5MW of e+e- pairs with a very broad energy spectrum need to be disposed along the post-collision line. The conceptual design of this beam line will be presented. Emphasis will be on the optimization studies of the CLIC post-collision line design with respect to the energy deposition in windows, dumps and scrapers, on the design of the luminosity monitoring for a fast feedback to the beam steering and on the background conditions for the luminosity monitoring equipment. |
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| WEPE020 | Background at the Interaction Point from the CLIC Post-Collision Line | 3389 |
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The 1.5TeV CLIC beams, with a total power of 14MW per beam, are disrupted at the interaction point due to the very strong beam- beam effect. The resulting spent beam products are transported to suitable dumps by the post-IP beam line, which generates beam losses and causes the production of secondary cascades towards the interaction region. In this paper the electromagnetic background at the IP are presented, which were calculated using biased Monte Carlo techniques. Also, a first estimate is made of neutron back-shine from the main beam dump. |