On all three spectrometers, the scintillation detector system is set up by two thin (3 mm and 10 mm), segmented planes of plastic scintillator material, with each segment read out individually by two photomultiplier tubes. The main purpose of the scintillation detector system is:
- The determination of the time when a particle hits the detector system, which is needed for the coincidence with the other spectrometers and as a time reference for the drift chambers.
- The discrimination of particles due to their specific energy loss in the scintillator. In the energy range where the spectrometers are operating, the particles in question are protons and deuterons on the one side and positrons and positive pions on the other side.