sentences:  In 1964 Crewe developed the first field emission electron gun in collaboration with Hitachi, a new type of electron source that enabled much higher optical quality than had previously been possible.This gun, combined with inventions in electron lenses and detection, led to the development of the highest resolution microscope at that time.In 1970 his field emission scanning transmission electron microscope succeeded in taking images individual atom (though not the first, this achievement usually being credited to Erwin Muller).