100 cm long time-of-flight scintillation counters with rms resolution of 50 ps

Abstract We tested time-of-flight counters with four combinations of scintillators and photomultipliers. We examined two plastic scintillators (SCSN-23 and SCSN-38) and three 2 inch photomultipliers (R329, R1828 and R2083). The dimensions of both scintillators were 3.5 cm wide, 4 cm thick and 100 cm long. Time of flight was measured for minimum ionizing particles between a small scintillation counter and the test counter. We studied the dependence of the time resolution on the high voltage of the photomultiplier, and on the hit-position on the scintillator. The rms time resolution of 50 ps was achieved after software correction for a time-walk effect. The shape of the TOF spectra after the correction was found to remain a Gaussian distribution over three orders of magnitude. We also studied the dependence of TOF value on the hit-position, and found that most of the values at edges of the scintillator were 50–100 ps smaller than those at the center.