Energy response and resolution to positrons in a capillary-tube dual-readout calorimeter prototype

We present the results of a test beam campaign on a capillary-tube fibre-based dual-readout calorimeter, designed for precise hadronic and electromagnetic energy measurements in future collider experiments. The calorimeter prototype consists of nine modules, each composed of brass capillary tubes housing scintillating and Cherenkov optical fibres, read out using silicon photomultipliers for the central module and photomultiplier tubes for the outer modules. The performance of the detector was assessed using a positron beam with energies ranging from 10 to 120 GeV at the CERN SPS H8 beamline. The prototype is characterised in terms of the linearity and resolution of its energy response to positrons. The results confirm the performance of the capillary-tube mechanical design for large-scale dual-readout calorimetry and provide a benchmark for future detector development within the HiDRa project.