Speaker
Giacomo Govi
(Fermilab)
Description
CMS experiment is made of many detectors which in total sum up to
60 million channels. Calibrations and alignments are fundamental to
maintain the design performance of the experiment. The conditions
database contains the alignment and calibrations data for the various
detectors.
Conditions data sets are accessed by a tag and an interval of validity through the offline reconstruction program CMSSW, written in C++.
Performant access to the conditions data as C++ objects is a key
requirement for the reconstruction and data analysis.
About 200 types of calibration and alignment exist for the various
CMS sub-detectors. Each set is grouped in a so-called "global tag"
which is valid for a given period of data-taking and for a given data
set (Monte Carlo events or collisions data).
Only those data which are crucial for reconstruction are inserted into the offline conditions DB. This guarantees a fast access to conditions during reconstruction and a small size of the conditions DB.
The talk describes the experience with the offline reconstruction
conditions database during 2010 and prospects for the future.
Authors
Andreas Pfeiffer
(CERN)
Antonio Pierro
(INFN Bari)
Francesca Cavallari
(Univ. + INFN Roma 1)
Giacomo Govi
(Fermilab)
Salvatore Di Guida
(CERN)
Vincenzo Innocente
(CERN)
