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Description
SHiP (Search for Hidden Particles) is a general-purpose beam dump experiment in preparation at CERN. Its goal is to search for new feebly interacting particles at the GeV scale in an environment of near zero background. The Surrounding Background Tagger (SBT) is a key part of SHiP's background suppression system. It detects muons entering SHiP's helium-filled decay volume from the sides, as well as muon and neutrino inelastic interactions within the volume.
The SBT consists of about 800 cells filled with liquid scintillator as the active detector material (LAB+PPO). The scintillation photons in each cell are read out by two Wavelength-shifting Optical Modules (WOMs), optically coupled to an array of 40 Silicon Photomultipliers (SiPMs) each.
This work presents results from performance studies of SBT prototypes developed and tested between 2022 and 2025 at the CERN PS and at DESY Hamburg test beam facilities. The prototypes explore different cell materials and production techniques to improve the overall light yield, a crucial factor for efficiency, time and spacial resolution. The results include the timing performance and the detector's efficiently.