Triple mode electrostatic collimator

A system includes a first electrode to receive an ion beam, a second electrode to receive the ion beam after passing through the first electrode, the first and second electrode forming an upstream gap defined by a convex surface on one of the first or second electrode and concave surface on the other electrode, a third electrode to receive the ion beam after passing through the second electrode, wherein the second and third electrode form a downstream gap defined by a convex surface on one of the second or third electrode and concave surface on the other electrode, wherein the second electrode has either two concave surfaces or two convex surfaces; and a voltage supply system to independently supply voltage signals to the first, second and third electrode, that accelerate and decelerate the ion beam as it passes through the first, second, and third electrode. 种系统包含：第电极，用于接收离子束；第二电极，用于接收穿过第电极之后的离子束，其中第电极与第二电极中的其中之的凸面和其中另的凹面界定上游间隙；第三电极，用于接收穿过第二电极之后的离子束，其中第二电极与第三电极中的其中之的凸面和其中另的凹面界定下游间隙，第二电极具有两个凹面或两个凸面；以及电压供应系统，用