Validation of GEANT4 Monte Carlo models with a highly granular scintillator-steel hadron calorimeter

Abstract

Calorimeters with a high granularity are a fundamental requirement of the Particle Flow paradigm. This paper focuses on the prototype of a hadron calorimeter with analog readout, consisting of thirty-eight scintillator layers alternating with steel absorber planes. The scintillator plates are finely segmented into tiles individually read out via Silicon Photomultipliers. The presented results are based on data collected with pion beams in the energy range from 8 GeV to 100 GeV. The fine segmentation of the sensitive layers and the high sampling frequency allow for an excellent reconstruction of the spatial development of hadronic showers. A comparison between data and Monte Carlo simulations is presented, concerning both the longitudinal and lateral development of hadronic showers and the global response of the calorimeter. The performance of several GEANT4 physics lists with respect to these observables is evaluated.

Experimental tests of particle flow calorimetry

“…For the analysis of longitudinal profiles in the steel AH-CAL (Adloff et al, 2013b), the capability to reconstruct the shower start from the three-dimensional hit distribution has been used to de-convolute the distribution of average energy per layer into a spectrum of depth of the first hard interaction, and a profile measured from this first interaction point. This provides a cross-check of the material composition and nuclear absorption properties in the simulation, and a profile which is more directly sensitive to the physics processes at different stages of the shower evolution, as already seen in the silicon tungsten ECAL discussed above.…”

Measurement of meson resonance production in $$\pi ^-+$$ π - + C interactions at SPS energies

“…Hadronic interaction models used for calorimeter simulations are mostly tuned to and validated with the overall calorimeter response from test-beam data (see e.g. [34][35][36]). A tuning of these models to the data presented here will improve the description of the energy transfer from the hadronic to the electromagnetic shower component for individual interactions inside the calorimeter and thus increase the predictive power of the calorimeter simulation.…”

Shower development of particles with momenta from 15 GeV to 150 GeV in the CALICE scintillator-tungsten hadronic calorimeter

“…Thus fluctuations of the shower start are disentangled from the intrinsic longitudinal shower development. The layer in which the shower started is identified using the clustering algorithm described in [18]. We found that data and Monte Carlo at all beam momenta agree in terms of the reconstructed, exponentially falling shower start layer distribution within 2% for shower starts in the most relevant first 15 layers.…”

“…Uncertainties due to layer-by-layer fluctuations of the calorimeter response generated by uncertainties in the calibration and saturation effects are taken into account, in addition to the systematic uncertainties discussed in section 6. The uncertainty due to layer-by-layer fluctuations is estimated by the difference between the effect observed in data and simulations following the procedure described in [18]. A comparison of the longitudinal profile in data and Monte Carlo for 25 GeV and 150 GeV π + events is shown in figure 15.…”