Münster 2017 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 118: Trigger und DAQ 3

T 118.5: Vortrag

Donnerstag, 30. März 2017, 17:50–18:05, VSH 05

Enhanced Bunch Crossing Identification for Saturated Pulses in the ATLAS Level-1 Calorimeter Trigger — •Claire Antel — Kirchhoff-Institut für Physik, Heidelberg

The ATLAS Level-1 Trigger system is designed to perform an ultrafast analysis of a collision provided by the Large Hadron Collider (LHC) in order to to decide within 2.5 microseconds whether to keep the event for further processing. The ATLAS Level-1 Calorimeter Trigger participates in this decision by processing calorimeter-based information from the detector. The preprocessing of the signals includes the identification of the correct bunch crossing (BCID) in which the collision took place; failure to do so will lead to events being irrevocably lost.

In view of the increased collision energy in Run II, a new BCID algorithm was commissioned in the Level-1 Calorimeter Trigger that targets saturated pulses. The algorithm is based on new capabilities offered by hardware upgrades in the calorimeter trigger, namely the implementation of new multi-chip modules that have a 80 MHz digitisation rate - twice that of the previous system. The inputs of the algorithm are the 80 MHz digitised samples on the rising edge of the pulse. Thus in order to tune the algorithm, the pulse shapes of signals from physics collision events were studied, using special runs with 80 MHz readout.

The algorithm was commissioned throughout 2016 and enabled towards the end of the year’s proton physics data taking period. Presented here is the commissioning as well as the initial performance of the new saturated BCID algorithm.