  A $^{6}$Li glass based scintillation detector developed for the TRIUMF
neutron electric dipole moment experiment was characterized using the
ultra-cold neutron source at the Paul Scherrer Institute (PSI). The data
acquisition system for this detector was demonstrated to perform well at
rejecting backgrounds. An estimate of the absolute efficiency of background
rejection of $99.7\pm0.1$% is made. For variable ultra-cold neutron rate
(varying from $<$1 kHz to approx. 100 kHz per channel) and background rate seen
at the Paul Scherrer Institute, we estimate that the absolute detector
efficiency is $89.7^{+1.3}_{-1.9}$%. Finally a comparison with a commercial
Cascade detector was performed for a specific setup at the West-2 beamline of
the ultra-cold neutron source at PSI.
