Test beam measurements of the CMS High Granularity Calorimeter

Abstract

As part of the High Luminosity LHC detector upgrade programme, the CMS experiment is developing a High Granularity Calorimeter (HGCAL) to replace the existing endcap calorimeters. The HGCAL will be realised as a sampling calorimeter, including 36 layers of silicon pads and 14 layers combining both silicon and scintillator detectors interspersed with metal absorber plates. Prototype modules based on 6-inch hexagonal silicon pad sensors with pad areas of 1.0 cm2 have been constructed. Beam tests of different sampling configurations made from these modules have been conducted at the CERN SPS using beams of charged hadrons and electrons with momenta ranging from 20 to 300 GeV/c. The setup was complemented with a CALICE Analog Hadronic Calorimeter (AHCAL) prototype, a scintillator-based sampling calorimeter, mimicking the proposed design of the HGCAL scintillator part. Test beam measurements at CERN in October 2018 are presented, including measurements of pedestal and noise, calibration with single charged particles and energy reconstruction performance of electron and hadron induced showers. Measurements of the timing capabilities of this prototype system are also reported.