LDMX HCal read-out chip board characterization and diagnostics

Sammanfattning

The search for the dark matter (DM) particle has recently found itself at the forefront of physics research. Numerous experiments designed to capture the invisible particle have contributed to constraining its possible energy range. The Light Dark Matter eXperiment (LDMX) aims to delve into the yet unexplored sub-GeV region, searching for “light” DM (LDM). The experiment is designed to infer LDM production from the missing-momentum of electrons, scattered via the “dark bremsstrahlung” process. To identify this event, LDMX employs a wide array of trackers and detectors. Due to the dark bremsstrahlung’s low likelihood, LDMX must diligently exclude all other energy signatures. The hadronic calorimeter (HCal) plays an important role in ensuring the experiment’s high veto power. In this study, we characterize and evaluate the reliability of the HCal’s front-end read-out - the High Granularity Read Out Chip (HGCROC) board. We examine the read-out of ten H2GCROCv3b boards using internal charge-injections. The injections follow a novel automated testing procedure, configured via the pflib control software. We review the results over four evaluation metrics to assess the health of the chip board and the control software. Using these metrics, we identify and classify various read-out irregularities. Furthermore, we develop a read-out irregularity identification algorithm, as part of the pflib library.