  We have obtained time-resolved spectroscopic observations for a sample of 10
cool Ap stars using the ultra-stable spectrograph HARPS at the ESO 3.6-m
telescope. The aim of our study was to search for low-amplitude oscillations in
Ap stars with no or inconclusive evidence of pulsational variability. Here we
report initial results of our investigation. We confirm the presence of ~16-min
period pulsations in beta CrB (HD 137909) and demonstrate multiperiodic
character of oscillations in this star. Furthermore, we discovered very low
amplitude 9-min pulsations in HD 75445 - an object spectroscopically very
similar to known roAp stars.
