  This paper summarizes the results from measurements aiming to characterize
ultracold neutron detection with 6Li-doped glass scintillators. Single GS10 or
GS20 scintillators, with a thickness of 100-200 micrometer, fulfill the
ultracold neutron detection requirements with an acceptable neutron-gamma
discrimination. This discrimination is clearly improved with a stack of two
scintillators: a 6Li-depleted glass bonded to a 6Li-enriched glass. The optical
contact bonding is used between the scintillators in order to obtain a perfect
optical contact. The scintillator's detection efficiency is similar to that of
a 3He Strelkov gas detector. Coupled to a digital data acquisition system,
counting rates up to a few 10^5 counts/s can be handled. A detector based on
such a scintillator stack arrangement was built and has been used in the
neutron electric dipole moment experiment at the Paul Scherrer Institute since
2010. Its response for the regular runs of the neutron electric dipole moment
experiment is presented.
