Speaker
Description
The CMS electromagnetic calorimeter (ECAL) is a homogeneous, hermetic calorimeter comprised of 75,848 lead tungstate (PbWO4) crystals which is optimized for measuring the transverse energy of electrons and photons during LHC collisions. ECAL forms trigger primitives consisting of transverse energy sums and other deposit characteristics which are fed to the CMS Level-1 (L1) trigger at the 40 MHz collision rate. These are used in tandem with information from other subsystems to trigger full CMS readout to storage. Within the on-detector electronics in the barrel region of ECAL, a set of sample weights are used to reconstruct the amplitudes of incoming signals. Large-amplitude signals, termed “spikes”, resulting from direct incidence of hadrons on the APDs, occur during LHC collisions. If untreated, these “spikes” would degrade the performance of the L1 trigger by saturating the trigger bandwidth, and a hardware-based spike killer has been used to reject these. A second set of unused weights in the on-detector electronics which duplicates the amplitude reconstruction data path is currently being explored as a means of improving the performance of the hardware-level spike killer by exploiting the timing profile of spikes. This poster will present an overview of this work along with a discussion of the impact of this mechanism on L1 objects such as electrons, photons, tau leptons, and jets, including the potential use of this configuration in the remainder of Run 3.
