Abstract
Cathode strip chambers are designed for the muon system of the compact muon solenoid under construction at CERN. These chambers must ensure a high accuracy (∼100 μm) of measurements of muon coordinates under heavy background conditions, when ∼20% of measured muon coordinates are contaminated by a secondary electromagnetic accompaniment and it is often impossible to separate overlapping hits. As a result of this contamination, the distribution of measurement errors differs substantially from a normal (Gaussian) distribution. In these cases, the traditional least squares method is inapplicable. For this reason, a robust (stable against noise) iteration procedure is proposed for fitting track segments in cathode strip chambers. The optimal weight function is derived in an explicit form with allowance for actual contamination introduced by the electromagnetic accompaniment. A comparative analysis is carried out for simulated and experimental data from the chamber prototype. The results conclusively indicate that the robust approach must be applied to fit tracks in cathode strip chambers when data are heavily contaminated.
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Golutvin, I.A., Kiryushin, Y.T., Movchan, S.A. et al. Robust Optimal Estimates of the Parameters of Muon Track Segments in Cathode Strip Chambers for CMS Experiments. Instruments and Experimental Techniques 45, 735–741 (2002). https://doi.org/10.1023/A:1021410517722
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DOI: https://doi.org/10.1023/A:1021410517722