CERN Accelerating science

CMS Note
Report number	CMS-CR-2009-330
Title	First Alignment of the Complete CMS Silicon Tracker
Author(s)	Kaschube, Kolja (Hamburg U.)
Publication	2009
Collaboration	CMS Collaboration
Imprint	06 Nov 2009
Number of pages	6
Presented at	IEEE Nuclear Science Symposium And Medical Imaging Conference, Orlando, FL, USA, 25 Oct - 31 Oct 2009
Subject category	Detectors and Experimental Techniques
Accelerator/Facility, Experiment	CERN LHC ; CMS
Keywords	General ; Tracker
Abstract	We present the first results of the full CMS Silicon Tracker alignment based on several million reconstructed tracks from the cosmic data taken during commisioning runs with the detector in its final position. The all-silicon design of the CMS Tracker poses new challenges in aligning a complex system with 15148 silicon strip and 1440 silicon pixel modules. For optimal track-parameter resolution, the position and orientation of its modules need to be determined with a precision of several micrometers. For the modules well illuminated by cosmic ray particles, the ultimate precision has been achieved with data from the silicon modules traversed in-situ by charged muons used in combination with survey measurements. The achieved resolution in all five track parameters is controlled with data-driven validation of the track parameter measurements near the interaction region, and tested against prediction with detailed detector simulation.
Copyright/License	Preprint: (License: CC-BY-4.0)