CERN Accelerating science

CMS Note
Report number CMS-CR-2008-016
Title Design and Performance of the Alignment System for the CMS Muon Endcaps
Author(s) Hohlmann, Marcus (Florida Inst. Tech.) ; Baksay, Gyongyi (Florida Inst. Tech.) ; Browngold, Max (Florida Inst. Tech.) ; Dehmelt, Klaus (Florida Inst. Tech.) ; Guragain, Samir (Florida Inst. Tech.) ; Andreev, Valery (UCLA) ; Yang, Xiaofeng (UCLA) ; Bellinger, James (Wisconsin U., Madison ) ; Carlsmith, Duncan (Wisconsin U., Madison ) ; Feyzi, Farshid (Wisconsin U., Madison ) ; Loveless, Richard J (Wisconsin U., Madison ) ; Northacker, David (Wisconsin U., Madison ) ; Case, Michael (UC, Davis) ; Eartly, David P (Fermilab) ; Prokofiev, Oleg (Fermilab) ; Sknar, Vladimir (St. Petersburg, INP) ; Sytnik, Valeri (UC, Riverside )
Submitted to 53rd Nuclear Science Symposium, San Diego, CA, USA, 29 Oct - 4 Nov 2006
Submitted by 16 May 2008
Subject category Detectors and Experimental Techniques
Accelerator/Facility, Experiment CERN LHC ; CMS
Free keywords DI-ALIG
Abstract The alignment system for the CMS Muon Endcap detector employs several hundred sensors such as optical 1-D CCD sensors illuminated by lasers and analog distance- and tilt-sensors to monitor the positions of one sixth of 468 large Cathode Strip Chambers. The chambers mounted on the endcap yoke disks undergo substantial deformation on the order of centimeters when the 4T field is switched on and off. The Muon Endcap alignment system is required to monitor chamber positions with \mbox{75-200 $\mu$m} accuracy in the R$\phi$ plane, $\approx$400 $\mu$m in the radial direction, and $\approx$1 mm in the z-direction along the beam axis. The complete alignment hardware for one of the two endcaps has been installed at CERN. A major system test was performed when the 4T solenoid magnet was ramped up to full field for the first time in August 2006. We present the overall system design and first results on disk deformations, which indicate that the measurements agree with expectations.
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 Record created 2008-06-18, last modified 2018-06-07


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