{HEAD ~ An external backing material} matched to the acoustic impedance of the CdS crystal is attached to {TAIL ~ the electrode} connected to the signal processing system 
{ HEAD ~ An external backing material } matched to the acoustic impedance of the CdS crystal is attached to { TAIL ~ the electrode } connected to the signal processing system
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH