A directly heated oxide cathode 1, wherein {HEAD ~ said core metal wire} comprises {TAIL ~ a tungsten core wire} or a rhenium tungsten core wire 
comprises
A directly heated oxide cathode 1 , wherein { HEAD ~ said core metal wire } comprises { TAIL ~ a tungsten core wire } or a rhenium tungsten core wire
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH