Exposing a fibre-based dual-readout calorimeter to a positron beam

A prototype of a dual-readout calorimeter using brasscapillary tubes surrounding scintillating and clear plastic opticalfibres was tested using beams of particles with energies between 10and 100 GeV produced by the CERN SPS. The scope of the test was tocharacterise the performance of the tube-based detector response topositrons in terms of response linearity, energy resolution, andlateral granularity. After calibrating the detector and processingthe output signal to correct for the energy dependency on theparticle impact point, the linearity of the measurement was found tobe better than 1%. The response to positron was compared to thatpredicted by a Geant4-based simulation, finding good agreement bothin terms of energy resolution and shower profile. These resultsconfirm the validity of the tube-based mechanical option and SiPMreadout as a promising one for future developments.