Conditions for the LHCb VELO

Contents

• List of implemented VELO conditions
• XML Representation of the VELO Conditions
• Detector Element Interface to VELO Conditions

Implemented VELO Conditions

As of January 26 2006 the following conditions are represented in the XmlConditions package and interfaced through the detector element classes. Note that the alignment conditions are covered elsewhere. Also note that at the time of this writing the next version of LHCb software is in the process of integration and conditions as well as the interface code are only available from the head of the CVS repository.

Associated with DeVelo

• Mapping of TELL1 ids to VELO sensors

Associated with DeVeloSensor

• Overall sensor readout status
• Strip information: readout status, bonding specifics
• Strip capacitances

XML Representation of the VELO Conditions

Since there is not yet a data base backend for the conditions, the representation in flat XML files is the only one currently available. The files reside in the Det/XmlConditions package. Three new catalogs were introduced for the representation of the VELO conditions. One, Sensors, is simply a sub-catalog of the Velo catalog. The other two are new top-level catalogs, namely ChannelInfo and HardwareProperties. These two catalogs might also be populated with conditions for other detector components. The file path and XML catalog path for the conditions is hown below.

Detector Element Interface to VELO Conditions

The simplest interface to the conditions would be to let the detector element classes hand out constant pointers to the Condition objects. This has some disadvanteges, however. Firstly it is much nicer if client code can simply ask the detector element via some meaningfully named method. Secondly there is a slight performance hit when the condition parameters are always retrieved via their names instead of reading them from a cache in the detector element. In case of the TELL1 to sensor map condition there is another reason: the XML backend does not yet allow for the representation of maps. So the map is represented as two vectors in the XML which then have to be converted to a map whenever the condition is updated in DeVelo. What follows is a brief description of the interfaces to the various conditions.

TELL1 to sensor mapping

Associated detector element:

Interface:

Comment:

Overall sensor readout

Associated detector element:

Interface:

Strip information

Associated detector element:

Interface:

Comment:

Strip capacitance

Associated detector element:

Interface: