Large Area Picosecond PhotoDetectors (LAPPDs) are photosensors based on
microchannel plate technology with about 400 cm2 sensitive area. The
external readout plane of a capacitively coupled LAPPD can be segmented into
pads providing a spatial resolution down to 1 mm scale. The LAPPD signals have
about 0.5 ns risetime followed by a slightly longer falltime and their
amplitude reaches a few dozens of mV per single photoelectron. In this article,
we report on the measurement of the time resolution of an LAPPD prototype in a
test beam exercise at CERN PS. Most of the previous measurements of LAPPD time
resolution had been performed with laser sources. In this article we report
time resolution measurements obtained through the detection of Cherenkov
radiation emitted by high energy hadrons. Our approach has been demonstrated
capable of measuring time resolutions as fine as 25-30 ps. The available
prototype had performance limitations, which prevented us from applying the
optimal high voltage setting. The measured time resolution for single
photoelectrons is about 80 ps r.m.s.Comment: 35 pages, 23 figure