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