  In the present paper the results obtained in the investigation of possible
diurnal effects for low-energy single-hit scintillation events of
DAMA/LIBRA-phase1 (1.04 ton $\times$ yr exposure) have been analysed in terms
of an effect expected in case of Dark Matter (DM) candidates inducing nuclear
recoils and having high cross-section with ordinary matter, which implies low
DM local density in order to fulfill the DAMA/LIBRA DM annual modulation
results. This effect is due to the different Earth depths crossed by those DM
candidates during the sidereal day.
