{HEAD ~ A hollow tube anode current collector} is sealed to {TAIL ~ a glass ring} which is sealed to a metal outer ring 
is sealed to
{ HEAD ~ A hollow tube anode current collector } is sealed to { TAIL ~ a glass ring } which is sealed to a metal outer ring
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH