  An analog hadron calorimeter (AHCAL) prototype of 5.3 nuclear interaction
lengths thickness has been designed and constructed by members of the CALICE
Collaboration. The AHCAL prototype consists of a 38-layer sandwich structure of
steel plates and 7608 scintillator tiles that are read out by
wavelength-shifting fibres coupled to SiPMs. The signal is amplified and shaped
with a custom-designed ASIC. A calibration/monitoring system based on LED light
was developed to monitor the SiPM gain and to measure the full SiPM response
curve in order to correct for non-linearity. Ultimately, the physics goals are
the study of hadronic shower shapes and testing the concept of particle flow.
The technical goal consists of measuring the performance and reliability of
7608 SiPMs. The AHCAL prototype was commissioned in test beams at DESY, CERN
and FNAL, and recorded hadronic showers, electron showers and muons at
different energies and incident angles.
