21-27 March 2009
Europe/Prague timezone

The CMS Muon System Alignment

24 Mar 2009, 17:30
Club D (Prague)

Club D


Prague Congress Centre 5. května 65, 140 00 Prague 4, Czech Republic
oral Online Computing Online Computing


Mr Pablo Martinez Ruiz Del Arbol (Instituto de Física de Cantabria)


The alignment of the Muon System of CMS is performed using different techniques: photogrammetry measurements, optical alignment and alignment with tracks. For track-based alignment, several methods are employed, ranging from a hit-impact point (HIP) algorithm and a procedure exploiting chamber overlaps to a global fit method based on the Millepede approach. For start-up alignment, cosmic muon and beam halo signatures play a very strong role, in particular as long as available integrated luminosity is still significantly limiting the size of the muon sample from collisions. During the last commissioning runs the first aligned geometries have been produced and validated, and have been used at the CMS offline computing infrastructure in order to perform improved reconstructions. This presentation develops the computational aspects related to the calculation of alignment constants at the CERN Analysis Facility (CAF), the production and population of databases and the validation and performance in the official reconstruction. Also the integration of track-based and other sources of alignment is discussed.

Primary author

Mr Pablo Martinez Ruiz Del Arbol (Instituto de Física de Cantabria)

Presentation Materials