applying a voltage across {HEAD ~ each extraction diode} for operating each extraction diode only reverse biased and electrically isolating each of {TAIL ~ said photodiodes} 
applying a voltage across { HEAD ~ each extraction diode } for operating each extraction diode only reverse biased and electrically isolating each of { TAIL ~ said photodiodes }
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL