Silicon photomultipliers as readout for a segmented Time-of-Flight plastic detector

Particle identification at radioactive ion beam facilities requires Time-of-Flight detectors with an optimal time resolution and high rate capability. Segmented plastic scintillators are a common option for such detectors. A promising approach to cope with the high segmentation of modern devices is the use of silicon photomultipliers (SiPMs) as readout of the Time-of-Flight detectors. A prototype device consisting of strips of plastic scintillator of 4.4 x 100 x 1 mm(3) readout at both ends by SiPMs of two different sizes was tested using a Xe-124 beam at 600 MeV/nucleon. Timing and time-over-threshold information were extracted. The time resolution of the prototype was found to vary with the applied voltage and the SiPM size. After optimizing the voltage, resolutions of 14.3(10) ps and 10.4(1) ps were obtained for SiPMs of 1 x 1 mm(2) and 3 x 3 mm(2) respectively. These results point to SiPMs being suitable as readout of plastic scintillators at radioactive ion beam facilities.