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