{HEAD ~ The apparatus} 1, further comprising an amplitude detector that detects an amplitude of the torsional motion of {TAIL ~ the cantilever} 
{ HEAD ~ The apparatus } 1 , further comprising an amplitude detector that detects an amplitude of the torsional motion of { TAIL ~ the cantilever }
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL