Performance Evaluation of a Crystal-Enhanced Collimation System for the LHC

The Large Hadron Collider (LHC) has been constructed at CERN (Conseil Européen pour la Recherche Nucléaire, Geneva, Switzerland), and recently started up. The LHC beams, currently accelerated to 3.5 TeV, are meant to reach the nominal energy of 7 TeV, and a total stored energy, in nominal conditions, of 360 MJ per beam [1, 2]. The contrast between the huge stored power and the delicate cryogenic environment calls for a sophisticated collimation system [3]. For overcoming the limitations of the actual collimation system, different upgrade solutions have been considered [4, 5, 6]; this Ph.D. work gives a first performance evaluation of a crystal-enhanced collimation system by analytical, experimental and simulation investigations. In this work, two crystal collimation experiments are described: the T980 (Tevatron, Chicago, U.S.) and the UA9 (SPS, CERN, Geneva, Switzerland). The data are analyzed and actual crystal performances are measured. These experimental results and their cross-check with dedicated simulations constitute the foundations of a weighted, critical prediction for the LHC. Different scenarios for a possible LHC crystal-enhanced collimation system have been simulated. Here the results are described and optimal parameters for a possible crystal collimator are proposed.

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