Analysis of the performance of low gain avalanche diodes for future particle detectors

Low-Gain Avalanche Diodes (LGAD) are the sensor of choicefor the timing detectors of the ATLAS and CMS experiments at theHigh Luminosity Large Hadron Collider (HL-LHC). This paperpresents the results of static and dynamic performance evaluationsof LGADs manufactured by Hamamatsu Photonics K.K. (HPK) andBrookhaven National Laboratory (BNL). Timing performance wasmeasured using β-scopes after a static characterization of thedevice (current-voltage and capacitance-voltage curves) and a timeresolution better than 35 ps was extracted under high operationalbias voltage before irradiation. This value is considered within thenominal requirements of the ATLAS project for un-irradiatedsensors. Transient Current Technique (TCT) was used to observe andanalyze a gain suppression mechanism, i.e. a decrease in gaincorrelated with increased laser intensities. TCAD simulations werecarried out to interpret the gain suppression of the BNL sensorsunder different conditions of bias voltage and laser intensity. Agood correspondence between experimental observations and TCADsimulations was found.