Apr 1, 2000
LHCb Computing Group
The LHCb Detector Description Framework
A coherent O-O framework has been developed for providing data describing
the LHCb experimental apparatus to be used by the simulation, reconstruction
and analysis applications. This framework is used for the realization of the
detector data service, which is one of the main components of the GAUDI architecture
in use in LHCb. Examples of detector description data are: the geometry and
alignment parameters, the electronics calibration and their organization, the
environmental parameters needed for the data processing, etc.
The detector description data are made
available to the physics algorithms through a number of transient objects.
These transient objects are hierarchically organized and are a view of a
global persistent representation, which is currently implemented in XML
format and takes into account versioning and validity time interval. Other
representations of the data are also provided to domain specific frameworks
such as Geant4 and visualisation components. We will present the use-cases that have
driven the development, the main design choices, and details of the first
implementation of the framework. Finally we describe how it is customized to
provide the specific needs of the various LHCb sub-detectors.