Overview of the electromagnetic calorimeter trigger system at the belle II experiment

Abstract

We have been developing the trigger system using the Electromagnetic Calorimeter(ECL) which is one of sub-detectors in the Belle II experiment. The ECL trigger system is based on Trigger Cell(TC), and each TC consists of 16 crystals. To make a decision of physics events at an online trigger level, energy deposit in the TC and the event timing are required. Therefore, we have performed the TC energy calibration by a method of comparing the ECL trigger data with the ECL data, and the TC time offset calibration by using a least χ2 algorithm. We report the calibration method and performance using cosmic ray data.