An X ray generator includes {HEAD ~ a cathode} having an emitter made of carbon nanotubes which emits {TAIL ~ electrons} by field emission and thus becomes a cold cathode electron emission source 
An X ray generator includes { HEAD ~ a cathode } having an emitter made of carbon nanotubes which emits { TAIL ~ electrons } by field emission and thus becomes a cold cathode electron emission source
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH