A voltage divider is connected between the negative side or cathode and ground and an intermediate point on the divider is connected to {HEAD ~ a focusing electrode} in {TAIL ~ the x ray tube} for providing a focusing bias voltage 
A voltage divider is connected between the negative side or cathode and ground and an intermediate point on the divider is connected to { HEAD ~ a focusing electrode } in { TAIL ~ the x ray tube } for providing a focusing bias voltage
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH