Design and Test-Beam Results of the FoCal-H Demonstrator Prototype

Abstract: The forward calorimeter (FoCal) of ALICE, planned to be operational for LHC Run 4, will cover the pseudorapidity range 3.4 $ \leq \eta \leq $ 5.8 allowing to probe the unexplored region of Bjorken-x down to $10^{-6}$. The hadronic section of the FoCal (FoCal-H) will be based on copper capillary tubes and scintillating fibers inside, with light read out by silicon photomultipliers (SiPM). A "proof of concept" demonstration prototype was built and tested in the H6 beamline at the CERN SPS in the beginning of October, 2021, exposing it to an unseparated charged particle beam with energy in the interval 20 GeV $-$ 80 GeV. The design of the prototype as well as the results of the energy reconstruction are presented and the validation with a GEANT4-based simulation is discussed.