Aligning the CMS Muon Chambers with the Muon Alignment System during an Extended Cosmic Ray Run

Abstract

The alignment system for the muon spectrometer of the CMS detector comprises three independent subsystems of optical and analog position sensors. It aligns muon chambers with respect to each other and to the central silicon tracker. System commissioning at full magnetic field began in 2008 during an extended cosmic ray run. The system succeeded in tracking muon detector movements of up to 18 mm and rotations of several milliradians under magnetic forces. Depending on coordinate and subsystem, the system achieved chamber alignment precisions of 140-350 microns and 30-200 microradians, close to the precision requirements of the experiment. Systematic errors on absolute positions are estimated to be 340-590 microns based on comparisons with independent photogrammetry measurements.

References in corpus (4)

• Alignment of the CMS Silicon Tracker during Commissioning with Cosmic Rays
• Performance of CMS Muon Reconstruction in Cosmic-Ray Events
• Commissioning of the CMS Experiment and the Cosmic Run at Four Tesla
• Alignment of the CMS Muon System with Cosmic-Ray and Beam-Halo Muons

Cited by in corpus (7)

• The performance of the CMS muon detector in proton-proton collisions at sqrt(s) = 7 TeV at the LHC
• Precise Mapping of the Magnetic Field in the CMS Barrel Yoke using Cosmic Rays
• Commissioning of the CMS Experiment and the Cosmic Run at Four Tesla
• Performance of the CMS Drift Tube Chambers with Cosmic Rays
• Alignment of the CMS Muon System with Cosmic-Ray and Beam-Halo Muons
• CMS Data Processing Workflows during an Extended Cosmic Ray Run
• Mechanical stability of the CMS strip tracker measured with a laser alignment system