Construction, Commissioning and First Results of a Highly Granular Hadron Calorimeter with SiPM-on-Tile Read-out

The CALICE collaboration is developing a highly granular Analogue Hadron sampling CALorimeter (AHCAL) for a future electron-positron collider. Very small detection units are required for the AHCAL due to an optimized design for the Particle Flow Algorithm. This is realized with scintillator tiles each wrapped in reflector foil and individually read out by a silicon photomultiplier (SiPM). These scintillator tiles and SiPMs are assembled on readout boards (HCAL Base Unit, HBU) which are integrated later on in the AHCAL detector stack. With this design a higher energy resolution is achievable, but also a large quantity of components (around 8,000,000 scintillator tiles and SiPMs) are needed to cover the detection area. To lessen the assembly time and also to assure a proper quality check and control of the final AHCAL an optimized assembly and testing chain is essential. With a large technological prototype both scalability of this project and a reliable operation of a larger number of channels, can be demonstrated. Also, several relevant quantities can be measured in an electron / hadron test beam like energy linearity and resolution for electrons and pions up to 100 GeV including shower profiles and separation. This document recaps the joint efforts of the AHCAL groups to install such an assembly and testing chain in different institutes for the large AHCAL technological prototype with around 22,000 channels. First promising results of the test beams at CERN SPS in summer 2018 are shown.