A flange member is provided on {HEAD ~ an outer wall} of the vacuum chamber to cover {TAIL ~ an opening} in the wall 
to cover
A flange member is provided on { HEAD ~ an outer wall } of the vacuum chamber to cover { TAIL ~ an opening } in the wall
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH