The high luminosity upgrade of the Large Hadron Collider (HL-LHC) at
CERN is expected to provide instantaneous luminosities of
5x10^34 cm^−2 s^−1. The high luminosities expected at the HL-LHC will be accompanied by a factor of 5 to 10 more pileup compared with LHC conditions, causing general
confusion for particle identification and event reconstruction. Precision timing
allows to extend calorimetric measurements into such a high density environment
by subtracting the energy deposits from pileup interactions. Calorimeters
employing silicon as the active component have recently become a popular choice
for the HL-LHC and future collider experiments which face very high radiation
environments. We present studies of basic calorimetric and precision timing
measurements using a prototype composed of tungsten absorber and silicon sensor
as the active medium. We show that for the bulk of electromagnetic showers
induced by electrons in the range of 20 GeV to 30 GeV, we can achieve time
resolutions better than 25 ps per single pad sensor.