  Large-scale optical neutrino and dark-matter detectors rely on large-area
photomultiplier tubes (PMTs) for cost-effective light detection. The new
R14688-100 8-inch PMT developed by Hamamatsu provides state-of-the-art timing
resolution of around 1 ns (FWHM), which can help improve vertex reconstruction
and enable Cherenkov and scintillation light separation in scintillation-based
detectors. This PMT also provides excellent charge resolution, allowing for
precision photoelectron counting and improved energy reconstruction. The Eos
experiment is the first large-scale optical detector to utilize these PMTs. In
this manuscript we present a characterization of the R14688-100 single
photoelectron response, such as the transit-time spreads, the dark-rates, and
the afterpulsing. The single photoelectron response measurements are performed
for the 206 PMTs that will be used in Eos.
