In-beam tests of scintillating fibre detectors at MAMI and at GSI

The performance of scintillating fibre detectors was studied with electrons at the spectrometer facility of the Mainz microtron MAMI, as well as in a 12C beam of 2 AGeV energy and in a beam of different particle species at GSI. Multi-anode photomultipliers were used to read out one or more bundles of 128 fibres each in different geometries. For electrons a time resolution of FWHM ∼ 1 ns was measured in a single detector plane with a detection efficiency ε > 99 % . A time resolution of 310 ps (FWHM) between two planes of fibres was achieved for carbon ions, leading to a FWHM ∼ 220 ps for a single detector. The hit position residual was measured with a width of FWHM = 0.27 mm . The variation in the measured energy deposition was Δ E / E = 15 –20% (FWHM) for carbon ions. In addition, the energy response to p / π + / d particles was studied. Based on the good detector performance fibre hodoscopes will be constructed for the Kaos/A1 spectrometer at MAMI and for the HypHI experiment at GSI.