  We assess local-time variations of epithermal-neutron count rates measured by
the Lunar Prospector Neutron Spectrometer. We investigate the nature of these
variations and find no evidence to support the idea that such variations are
caused by diurnal variations of hydrogen concentration across the lunar
surface. Rather we find an anticorrelation between instrumental temperature and
epithermal-neutron count rate. We have also found that the measured counts are
dependent on the temperatures of the top decimeters of the lunar subsurface as
constrained by the Lunar Reconnaissance Orbiter Diviner Lunar Radiometer
Experiment temperature measurements. Finally, we have made the first
measurement of the effective leakage depth for epithermal-neutrons of ~20 cm.
