A vacuum treatment system has {HEAD ~ an outer housing} which defines {TAIL ~ a substantially cylindrical inner wall} around an axis 
defines
A vacuum treatment system has { HEAD ~ an outer housing } which defines { TAIL ~ a substantially cylindrical inner wall } around an axis
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH