Speaker
Description
The CMS Collaboration is preparing to replace its current endcap calorimeters with the High Granularity Calorimeter (HGCAL) for the High Luminosity LHC (HL-LHC) era. HGCAL features unprecedented transverse and longitudinal granularity, enabling detailed measurement of shower development with 5D information. The detector employs silicon sensors in the electromagnetic section and high-radiation regions of the hadronic section, and plastic scintillator tiles with SiPM readout in lower-radiation regions of hadronic section, integrated into cassettes of varying geometries. Fermilab is responsible for assembling 504 cassettes for the hadronic section of the calorimeter. Having successfully completed the pre-series phase, the project is now transitioning into full production. This contribution reports on Fermilab’s pre-series experience and production readiness. Two cold rooms have been commissioned at Fermilab, capable of operating at -35°C and enabling simultaneous cooling and readout of multiple cassettes for validation and cosmic data taking. A module test stand was established to qualify silicon modules for assembly. Both all-silicon and mixed silicon-plus-SiPM tile cassettes were successfully assembled, and lessons learned from the pre-series phase are being incorporated into the production workflow. Full electronic chain readout was validated end-to-end, from sensor through HGCROC, ECON-D/T, lpGBT, optical fiber, to backend FPGA firmware. Automated software was developed to convert raw readout data into structured formats suitable for data quality monitoring and enabling rapid assessment of cassette assembly.