A removable, replaceable ring at the lower opening of the processing chamber allows {HEAD ~ process} pumping {TAIL ~ speed} to be tailored for different processes by replacing the ring 
pumping
A removable , replaceable ring at the lower opening of the processing chamber allows { HEAD ~ process } pumping { TAIL ~ speed } to be tailored for different processes by replacing the ring
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH