Online Calibration

Mailing List: D0_ONLINE_CALIBRATION

Periodic calibration of the sub-detector systems is one of the most important tasks during the data taking in the D0 Run II. Most sub-detector systems will take special data during the quiet time between the beam stores for calibration, collecting pedestals or measuring gains by injecting electronic charges to the front-end amplifiers. These data are analysed online in the front-end processors in the case of SMT, or in the Level 3 nodes in the case of Calorimeter, or analysed offline in the cases of CFT, CPS, and FPS, which uses a common readout system, and the muon systems. The calibration constants are inserted into the online ORACLE database. These constants will be transfered from the online database to the offline database for later use in the data analysis.

The Online Calibration group is working on a system in which all the calibration processes are orchestrated by a single process running on an online host computer. The program to orchestrate the process is called Calib_Manager and is packaged as onl_calib_system in d0cvs. People who are responsible for the calibration of each sub-detector system provide the database table design, the data analysis program to calculate the calibration constants, etc. The database access will be done by a common interface for all sub-detector systems. The interface for ORACLE database access is packaged as onl_calDbAccess. After calibration constants have been written to the online database, those constants deemed good/used in the download to the frontend electronics are transfered to the offline calibration database using onl_calDbTransfer.