Timing properties of Hamamatsu R5912-MOD photomultiplier tube for the ICARUS T600 light detection system

The ICARUS T600 liquid argon time projection chamber (LAr-TPC) will operate at shallow depth as far detector for the Short Baseline Neutrino (SBN) program at FNAL. A new scintillation light detection system, with a time resolution of the order of the nanosecond, is required to distinguish the actual beam related events from the huge cosmic background. The chosen photomultiplier tube (PMT) model is the Hamamatsu R5912-MOD. This has an 8 in. diameter window made of borosilicate glass, 10 dynodes and a bialkali photo-cathode with platinum undercoating, suitable for cryogenic applications. The main timing characteristics of this PMT model – namely the absolute transit time vs. power supply, the transit time spread for light hitting different window places and for different PMT orientations with respect to the Earth’s magnetic field – have been evaluated in order to confirm the suitability of this PMT model to the requirements of the SBN program.