converted by wavelength-shifting fibers embedded in the scintillator and channeled to hybrid photodiode detectors via clear fibers. The outer calorimeter [@cite:epjcHO] utilizes the CMS magnet coil/cryostat and the steel of the magnet return yoke as its absorber, and uses the same active material and readout system as the barrel and endcap calorimeters. The forward calorimeter is based on Cherenkov light production in quartz fibers and is not discussed in this paper, due to its different signal time structure.

The HCAL is segmented into individual calorimeter cells along three coordinates, $\eta$, $\phi$, and depth. The $\phi$ coordinate is the azimuthal angle and $\eta$ is the pseudorapidity. The depth is an integer coordinate that enumerates the segmentation longitudinally, along the direction from the center of the nominal interaction region. The layout of the barrel, endcap and outer calorimeter cells is illustrated in Fig. \[fig:HCALdiagram\]. Most cells include several scintillator layers; for example, in most of the barrel all 17 scintillator layers are combined into a single depth segment.

Calorimetric measurements are acquired using the HCAL readout electronics, shown schematically in Fig. \[fig:HCALreadout\]. Each electronics channel collects and processes the signal of a single cell. One calorimetric measurement is acquired with each LHC 