Shower Leakage Correction in a High Granularity Calorimeter

TL;DR

This paper presents a method to correct for shower leakage in a high granularity calorimeter, significantly improving energy measurement accuracy and resolution, based on experimental data and Monte Carlo simulations.

Contribution

The study introduces a topological leakage correction technique for high granularity calorimeters, validated with CERN test beam data, enhancing energy measurement accuracy.

Findings

Leakage correction restores mean energy to within 1-2% of true value.

Resolution improves by about 25% at 80 GeV after correction.

Correction effectiveness decreases at lower energies.

Abstract

In the ILD detector, HCAL is inside the coil. The HCAL is about 5 interaction length thick, and ECAL is about 1 interaction length thick. For example, an eighty GeV hadron, it is only 95% energy will be contained in ECAL plus HCAL. We need a topological reconstruction of the leakage. This has been studied with experimental data collected using the CALICE prototypes, during the 2007 test beam campaign at CERN. The complete setup of the experiment consisted of a silicon-tungsten electromagnetic calorimeter, an analog scintillator-steel hadron calorimeter and a scintillator-steel tail catcher. Events collected using pion beams in the energy range 8-100 GeV are selected and compared to the Monte Carlo simulations. While the leakage from the full setup is negligible, when removing the tail catcher information either partly or completely the energy loss becomes significant and affects the performance. The average measured energy decreases below the expected beam energy and the resolution deteriorates. A correction to the leakage was implemented for pions. The results obtained show that the correction is powerful in restoring the mean value of the measured energy distributions back to the expected beam energy, with an accuracy at the 1-2% level over the whole energy range. The relative improvement on the resolution is about 25% at 80 GeV, decreasing at lower energies together with the impact of the leakage.