The performance of the CMS photon and electron level-1 trigger
- Resource Type
- Conference
- Authors
- Thea, Alessandro
- Source
- 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC) Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2012 IEEE. :1791-1795 Oct, 2012
- Subject
- Bioengineering
Signal Processing and Analysis
Communication, Networking and Broadcast Technologies
Components, Circuits, Devices and Systems
Computing and Processing
- Language
- ISSN
- 1082-3654
Throughout the year 2011, the Large Hadron Collider (LHC) has operated with an instantaneous luminosity that has risen continually to around 4×10 33 cm −2 s −1 . With this prodigious high-energy proton collisions rate, efficient triggering on electrons and photons has become a major challenge for the LHC experiments. The Compact Muon Solenoid (CMS) experiment implements a sophisticated two-level online selection system that achieves a rejection factor of nearly 10 6 . The first level (L1) is based on coarse information coming from the calorimeters and the muon detectors while the High-Level Trigger (HLT) combines fine-grain information from all sub-detectors. In this intense hadronic environment, the L1 electron/photon trigger provides a powerful tool to select interesting events. It is based upon information from the Electromagnetic Calorimeter (ECAL), a high-resolution detector comprising 75848 lead tungstate (PbWO4) crystals in a “barrel” and two “endcaps”. The performance as well as the optimization of the electron/photon trigger are presented.