An electron emitter can include: a plurality of elongate rungs connected together end to end from a first emitter end to a second emitter end in a plane so as to form a planar pattern; a plurality of corners, wherein each elongate rung is connected to another elongate rung through a corner having a corner apex and an opposite corner nadir; a first gap between adjacent non-connected elongate rungs, wherein the first gap extends from the first emitter end to a middle rung; a second gap between adjacent non-connected elongate rungs, wherein the second gap extends from the second emitter end to the middle rung, wherein the first gap does not intersect the second gap; and one or more cutouts at one or more of the corners of the plurality of corners between the corner apex and corner nadir or at the corner nadir.