Particle Showers in a Highly Granular Hadron Calorimeter
The CALICE collaboration has constructed highly granular electromagnetic and hadronic calorimeter prototypes to evaluate technologies for the use in detector systems at a future Linear Collider. The hadron calorimeter uses small scintillator cells individually read out with silicon photomultipliers. The system with 7608 channels has been successfully operated in beam tests at DESY, CERN and Fermilab since 2006, and represents the first large scale tests of these devices in high energy physics experiments. The unprecedented granularity of the detector provides detailed information of the properties of hadronic showers, which helps to constrain hadronic shower models through comparisons with model calculations. We will discuss results on longitudinal and lateral shower profiles compared to a variety of different shower models, and present studies of the energy reconstruction of hadronic showers using software compensation techniques.
Max-Planck-Institut für Physik and Excellence Cluster ‘Universe’, Munich, Germany
1 The CALICE Calorimeters
The goal of the CALICE experimental program is to establish novel technologies for calorimetry in detectors at a future linear collider, and to record electromagnetic and hadronic shower data with unprecedented three dimensional spatial resolution for the validation of simulation codes and for the test and development of reconstruction algorithms. Such highly granular calorimeters are necessary to achieve an unprecedented jet energy resolution at the International Linear Collider [:2007sg] using particle flow algorithms [Brient:2002gh, Morgunov:2002pe, Thomson:2009rp].
The CALICE test beam setup consists of a silicon-tungsten electromagnetic calorimeter (ECAL), an analog scintillator-steel hadron calorimeter (AHCAL) and tail catcher/muon tracker (TCMT), the latter two both with individual cell readout by silicon photomultipliers (SiPMs) [Bondarenko:2000in]. This setup has been tested extensively in electron, muon, and hadron beams at CERN and at the Meson Test Beam Facility at Fermilab. Figure LABEL:fig:CALICESetup shows the schematic setup of the CALICE detectors in the CERN H6 test beam area, where data was taken in 2006 and 2007. The currently ongoing and the future program include the study of alternative technologies, such as an ECAL using scintillator strips with SiPM readout, digital hadron calorimeters with active layers based on gas detectors, and the investigation of alternative absorber materials for the hadron calorimeter for multi-TeV colliders.