Time-of-Flight Characteristics of Scintillation Counters with Fine-Mesh Photomultipliers

The characteristics of the time-of-flight system of scintillation counters with the ФЭУ-527 and R5505 fine-mesh-dynode photomultipliers for high-magnetic-field environment were measured. Scintillation counters with thin plastic scintillators 1, 3, and 5 mm thick were designed to operate in comparatively strong stray magnetic fields of up to several kilogauss. The measurements were carried out in beams of the U-10 proton synchrotron (Institute of Theoretical and Experimental Physics) with proton, π+-meson, and π–-meson momenta of 0.63, 1.03, and 1.28 GeV/c. For counters with scintillator sizes of 1 × 20 × 154 mm (BI-408) and 3 × 20 × 200 and 5 × 20 × 200 mm (Kuraray and SCSN-81), time resolutions of 45–180 ps were obtained. The time resolution of the scintillation counters, in which scintillators ∼ 20 mm thick and ФЭУ-527 photomultipliers were used, was found to be 50–80 ps.