Track Segments in Hadronic Showers in the Analogue Scintillator Tile HCAL

A simple track finder has been developed to study track segments of minimum ionizing particles within hadronic showers in the analog tile HCAL. As a proof of principle, the tracking algorithm was applied to muon data used for the calibration of the detector. Consistent results were obtained, with 94% of all analyzed channels within 5% of the value expected from the calibration. Tracks identified in hadron events showed energy loss spectra compatible with single MIP particles, demonstrating the capability to correctly identify minimum ionizing particles within hadronic showers. Using these tracks, the temperature dependence of the response of the SiPMs used in the calorimeter was determined. For 250 readout cells with sufficient statistics, a mean temperature slope of −3.6%K${^-1}$ was observed. This method of identifying MIP-like tracks in hadronic showers can provide a calibration strategy for a future ILC detector, where a sufficient number of muons for calibration is not available.