After ionization, {HEAD ~ all the ions} can be easily directed to the collection plates by {TAIL ~ an electric field} formed from the parallel plates 
directed by
After ionization , { HEAD ~ all the ions } can be easily directed to the collection plates by { TAIL ~ an electric field } formed from the parallel plates
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH