{HEAD ~ The heater} 56 has {TAIL ~ both ends} connected to a heater power supply 58 which controls the heating temperature of the heater 56 to regulate the temperature of the cathode 14, so that an amount of electron emission is controlled to adjust the tube current 
has
{ HEAD ~ The heater } 56 has { TAIL ~ both ends } connected to a heater power supply 58 which controls the heating temperature of the heater 56 to regulate the temperature of the cathode 14 , so that an amount of electron emission is controlled to adjust the tube current
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH