Development of Structured Scintillator Tiles for High-Granularity Calorimeters

Calorimeters with a fine 3-D segmentation are considered to be a very promising technology for future high-energy physics experiments, since they provide in combination with particle flow algorithms excellent jet energy resolution and particle identification capabilities. Depending on the size, millions of individual channels consisting of a photosensor coupled to a scintillator tile have to be assembled. The usage of structured plastic scintillators with optically separated segments simplifies the mass production. We present the design, production, and performance of a 36 cm × 36 cm scintillator tile divided into 144 segments matching the geometry of the SiPM-based calorimeter frontend developed within the CALICE collaboration. This approach features a full integration of scintillators, sensors, and electronics. For several prototypes the light yield of the channels and an upper limit for the optical crosstalk have been measured in a cosmic-ray test stand. Accompanying transparency and reflectivity studies with material samples, fabricated with different separation layers between the scintillating parts, have been performed. Conclusions from the development process on the optimum design and production technique are drawn.