For a material located at least in an upper layer of a plurality of {HEAD ~ materials} forming {TAIL ~ the object}, the secondary electron yield ratio can be made nearly unity and appropriate contrast of an obtained image can be provided with minimized influence of charge up 
For a material located at least in an upper layer of a plurality of { HEAD ~ materials } forming { TAIL ~ the object } , the secondary electron yield ratio can be made nearly unity and appropriate contrast of an obtained image can be provided with minimized influence of charge up
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH