{TAIL ~ Gas molecules} containing one of the isotopes are then deflected from {HEAD ~ the other gas molecules} in the stream and thus physically separated 
{ TAIL ~ Gas molecules } containing one of the isotopes are then deflected from { HEAD ~ the other gas molecules } in the stream and thus physically separated
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH