Online Calibration of the D0 Vertex Detector Initialization Procedure and Database Usage Harald Fox D0 Experiment Northwestern University

Online Calibration of the D0 Vertex Detector What is Online Calibration? Determination of: –Threshold for zero-suppression of the read out. –Pedestals and gains for the Level 3 Trigger and the Prompt Reconstruction.

When and Where? When? –Special calibration run between 2 machine fillings. –The time window for calibration is negotiable between D0, CDF, and the accelerator. –The Secondary Data Acquisition (SDAQ) is foreseen for this task.

When and Where? Where? –The calibration process runs on the front end processor of each readout crate. –Data is transferred to the CPU instead of the Level 3 Trigger. –Pedestals and gains are calculated locally and stored in the database. –New threshold values are calculated from pedestals.

What? The D0 Silicon Tracker consists of 6 barrels, 12 F-disks, and 8 H-disks  800,000 channels. Commissioning and testing requires read out of a complete barrel (432 SVX, channels). Each SVX read out chip has its own parameters.  DatabaseGUI ManipulationMonitoring

Calibration Steps A. Start a calibration run (Taker/COOR). B. Initialization of the electronics (“download”). –The initialization is part of COMICS. –An ORACLE database is used to store: Download Parameters History of time dependent information

Calibration Steps (cont.) C. Determine pedestals and gains (Huaming Wang). –5 Calibration voltages. –Pedestals and gains  Calibration Manager. D. The Validator checks errors and consistency.

Calibration Steps (cont.) E. Calibration data  Calibration Database. F. New thresholds are calculated. –Used for next initialization.

Design of the Electronics Database The hardware is mirrored: –Crates, modules, module channels, and silicon detectors. –Multiple to multiple connections between modules are allowed. Download parameters are stored. The path from a VME Readout Board (VRB) to a silicon detector (HDI) is traceable. A history of all modifications is kept.

The Initialization Process The initialization is integrated in the online environment (COMICS). A Python (OO-scripting language) program is used for downloading. The program is partitioned into 3 layers: 1.Hardware layer: Knows about module and register addresses. Communication via EPICS.

The Initialization Process (Program Layers) 2.The database layer: The hardware configuration is determined in a database lookup. Download parameters are extracted. 3.GUI for expert interaction: Allows modification of the database. Manipulation of each hardware module. Status display.

Database Layer Each hardware module and database table is represented by an object. The database is accessed via an interface design pattern. This allows an optimization of the database access. The electronics configuration is determined on a crate to crate basis. Each module is initialized in the proper sequence.

GUI Layer The GUI is an interaction tool for the experts. It replaces a PC based support tool. It gives an overview for each crate allowing basic operations.  Used for the barrel read out right now.

GUI Layer (cont.)

A detailed view allows interaction with all hardware modules. This allows the initialization of single modules or module chains. Allows modification of the database: –Enable/disable of modules for the subsequent download. –Change of hardware configuration (re-cabling). –Change of initialization parameters. –Calculation of new thresholds.

Use Cases Three test stands are available: Northwestern1% (SiDet)10% (SiDet) Complete Barrel 2 HDI 7 (72) HDI 2 VRB1 VRB5 (9) VRB 768 Channel2304 Channel4992 (55296) Channel

Milestone Goal Achieved! We successfully demonstrated the Online Calibration at the 10% test stand! The Silicon Tracker is the first detector using the complete Online Calibration System! Pedestals and gains were calculated and stored in the Online Database. Data was send to the Level 3 Trigger and saved to disk. SMT examine was used to monitor the data taking process.

Conclusion The D0 Silicon Tracker requires online calibration.  Demanding task with 800,000 channels! We developed database and GUI tools necessary to meet the challenge. We developed the program running on the Front End Processor determining pedestals and gains. These tools were successfully tested in the D0 Online Calibration Framework. We are leading the development.

Hardware Configuration VRB: VME Read Out Board SEQ: SVX Sequencer

Hardware Configuration VRB: VME Read Out Board SEQ: SVX Sequencer

UML Diagram of the Database Layer