Abstract: An ion implanter includes a high energy multistage linear acceleration unit for accelerating an ion beam. The high energy multistage linear acceleration unit includes high frequency accelerators in a plurality of stages provided along a beamline through which the ion beam travels, and electrostatic quadrupole lens devices in a plurality of stages provided along the beamline. The electrostatic quadrupole lens device in each of the stages includes a plurality of lens electrodes facing each other in a radial direction perpendicular to an axial direction, and disposed at an interval in a circumferential direction, an upstream side cover electrode covering a beamline upstream side of the plurality of lens electrodes and including a beam incident port, and a downstream side cover electrode covering a beamline downstream side of the plurality of lens electrodes and including a beam exiting port.

Abstract: An ion implanter includes a high energy multistage linear acceleration unit for accelerating an ion beam. The high energy multistage linear acceleration unit includes high frequency accelerators in a plurality of stages provided along a beamline through which the ion beam travels, and electrostatic quadrupole lens devices in a plurality of stages provided along the beamline. The electrostatic quadrupole lens device in each of the stages includes a plurality of lens electrodes facing each other in a radial direction perpendicular to an axial direction, and disposed at an interval in a circumferential direction, an upstream side cover electrode covering a beamline upstream side of the plurality of lens electrodes and including a beam incident port, and a downstream side cover electrode covering a beamline downstream side of the plurality of lens electrodes and including a beam exiting port.