Results of Beam Tests of a Prototype Calorimeter for a Linear Collider

The proposed International Linear Collider (ILC) requires a detector with superior jet energy resolution of 30%/√E or better near the Z-pole region (91GeV). The Calorimeter for the Linear Collider Collaboration (CALICE) is developing and testing prototype detectors with this goal in mind. One major limitation on detector resolution is the size of the hadron calorimeter contained within a magnetic coil. To compensate for "thin" calorimeters that cannot contain the highest energy particle showers, the Tail Catcher/Muon Tracker (TCMT) has been designed to include calorimetric functions and higher granularity than existing muon tracking systems. The prototype design also provided an opportunity to simulate the impact of a magnetic coil on energy resolution and to study the use of silicon photomultipliers (SiPMs) in particle detectors. This analysis shows that a TCMT six interaction lengths deep contains leakage and improves energy resolution when added to the CALICE electromagnetic and hadronic calorimeters. The effect of the TCMT both with and without a coil is more significant as energy increases. The addition of all sixteen layers of the TCMT to a 3.5 interaction length thick calorimeter improves pion resolution by 9.3% at 20 GeV and 10.8% at 80 GeV. For a 5.5 interaction length thick calorimeter system, typical of those under consideration for ILC detectors, the addition of TCMT layers after a coil of 1.8 interaction lengths improves energy resolution of 20 GeV pions by 1% and for 80 GeV pions by 2%.