The cathode of claim 7 where said cooling channel 7 where {HEAD ~ said cooling channel} is proximate {TAIL ~ said cathodic arc target} 
The cathode of claim 7 where said cooling channel 7 where { HEAD ~ said cooling channel } is proximate { TAIL ~ said cathodic arc target }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL