opy ▁( E EL S ) ▁are ▁commonly ▁used ▁techniques ▁to ▁both ▁qual it atively ▁and ▁quant it atively ▁pro be ▁the ▁composition ▁of ▁samples ▁in ▁the ▁T EM . ▁A ▁primary ▁challenge ▁in ▁the ▁quant itative ▁accuracy ▁of ▁both ▁techniques ▁is ▁the ▁phenomen on ▁of ▁ch ann elling . ▁Put ▁simply , ▁in ▁a ▁cry st all ine ▁solid , ▁the ▁probability ▁of ▁interaction ▁between ▁an ▁electron ▁and ▁ion ▁in ▁the ▁lattice ▁depends ▁strongly ▁on ▁the ▁momentum ▁( direction ▁and ▁velocity ) ▁of ▁the ▁electron . ▁When ▁prob ing ▁a ▁sample ▁under ▁diff raction ▁conditions ▁near ▁a ▁zone ▁axis , ▁as ▁is ▁often ▁the ▁case ▁in ▁E DS ▁and ▁E EL S ▁applications , ▁ch ann elling ▁can ▁have ▁a ▁large ▁impact ▁on ▁the ▁effective ▁interaction ▁of ▁the ▁incident ▁electrons ▁with ▁specific ▁ ions ▁in ▁the ▁cry stal ▁structure . ▁In ▁practice , ▁this ▁can ▁lead ▁to ▁err one ous ▁measurements ▁of ▁composition ▁that ▁depend ▁strongly ▁on ▁the ▁orientation ▁and ▁thick ness ▁of ▁the ▁sample ▁and ▁the ▁acceler ating ▁voltage . ▁Since ▁P ED ▁ent ails ▁an ▁integration ▁over ▁incident ▁directions ▁of ▁the ▁electron ▁pro be , ▁and ▁generally ▁does ▁not ▁include ▁be ams ▁parallel ▁to ▁the ▁zone ▁axis , ▁the ▁det r iment al ▁channel ing ▁effects ▁out lined ▁above ▁can ▁be ▁minim ized , ▁yield ing ▁far ▁more ▁accurate ▁composition ▁measurements ▁in ▁both ▁techniques . ▁ ▁References ▁ ▁External ▁links ▁▁ ▁N ano ME G AS ▁▁ ▁System ▁Design ▁and ▁Ver ification ▁of ▁the ▁Pre cess ion ▁Electron ▁D iff