  We developed an optical device for ultra-cold neutrons and investigated the
influence of a tilt of its guiding components. A measurement of the
time-of-flight of the neutrons through the device by means of a dedicated
chopper system was performed and a light-optical method for the alignment of
the guiding components is demonstrated. A comparative analysis of former
experiments with our results shows the potential of such a device to test the
electrical neutrality of the free neutron on the $10^{-22} q_{\rm e}$ level and
to investigate the interaction of neutrons with gravity.
