New visualization tool to operate high energy physics detectors

Abstract

The new high energy physics detectors like ALEPH are very complex and run for years. Their operation requires new tools. In this approach we give to the operator all the relevant information in graphical form in real time on the workstation screen in front of him. The pictorial form is necessary both to ensure an high communication bandwidth and to allow the immediate understanding of the detector status. This approach has been applied to two subdetectors of ALEPH, an apparatus taking data in one of the collision points of the LEP accellerator in the CERN laboratory on the Swiss-French border near Geneva. The two subdetectors are the hadron calorimeter and the muon detector. Together they have around 250 000 sensors: electronic channels that must individually be monitored for malfunction. A program has been developed to monitor them: the Hcal monitoring display which makes use of a 2D representation of the detector and displays on it the status of each channel in pseudocolor. This is similar to the representation of geographical data in atlases. The complex 3D structure of the apparatus is flattened in a 2D picture. Malfunctions appear as empty zones, strange colors, odd shapes.