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