It also reduces {HEAD ~ a length} of {TAIL ~ ionization region} and leads to a monochromatization of ion beam energy 
It also reduces { HEAD ~ a length } of { TAIL ~ ionization region } and leads to a monochromatization of ion beam energy
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH