An apparatus may include a housing including an entrance aperture, to receive an ion beam. The apparatus may include an exit aperture, disposed in the housing, downstream to the entrance aperture, the entrance aperture and the exit aperture defining a beam axis, extending therebetween. The apparatus may include an electrodynamic mass analysis assembly disposed in the housing and comprising an upper electrode assembly, disposed above the beam axis, and a lower electrode assembly, disposed below the beam axis. The apparatus may include an AC voltage assembly, electrically coupled to the upper electrode assembly and the lower electrode assembly, wherein the upper electrode assembly is arranged to receive an AC signal from the AC voltage assembly at a first phase angle, and wherein the lower electrode assembly is arranged to receive the AC signal at a second phase angle, the second phase angle 180 degrees shifted from the first phase angle.