The MiniCal was a small calorimeter prototype build and operated at DESY testbeam within the CALICE collaboration.
The purpose of this prototype was to gain experience in using new read out technics for a possible hadronic calorimeter (ILD calorimeter) of the future linear collider (ILC). It was also the predessesor of a larger prototype (internally called 'physics prototype'), which is making exessively use of the new readout scheme with SiPM readout.
The design of the MiniCal was simple. The MiniCal was a sampling calorimeter with 28 steel absorber plates. Each plate had a thicknes of 20 mm. The plates were stacked with a gap of 10 mm holding place for cassettes of 9 plastic scintillators with different readout technics. The plate sizes were 30x30 cm². The scintillator tiles had a size of 5x5 cm².
The scintillator tiles were read out with three different detectors:

• Photomultipliers - 2 Hamamatsu MAPM reading out up to 13 layers
• APDs - 33 pieces of 3x3 mm Hamamatsu special types reading out up to 13 layers
• SiPMs - 109 pieces of 1x1 mm Pulsar types (1024 pix) reading out up to 11 layers

To read more on MiniCal tests and results:

• S. Reiche on 'Studies for the Optical Read Out of a HCAL' (Diploma)
• H. Meyer on 'Studies of avalanche photo diodes for a calorimeter readout at a linear collider detector' (Diploma)
• 'A High-Granularity Scintillator Calorimeter Read Out with Silicon Photomultipliers' (NIM A 540 (2005) 368)
• 'A high-granularity plastic scintillator tile hadronic calorimeter with APD readout for a linear collider detector' (NIM A 564 (2006) 144)