Delta-phi microlens for low-energy particle beams

摘要

The Delta-Phi microlens consists of a first foil (3) of a metal or alloy from the group of transition metals and a second foil (4) of a metal or alloy from the group comprising the elements of IA or IIA groups of the periodic system of elements, the second foil (4) being coated onto one surface of said first foil (3). A hole (2) extends through both foils (3, 4) in precise alignment with the axis (6) of a sharply pointed tip (1) made of conductive material and placed at a distance of the order of 1 µm from that surface of said first foil (3) opposite said second foil (4). With the first foil (3) connected to ground and a potential on the order of -30 V applied at said tip (1), at ultra-high vacuum conditions, a beam of low-energy electrons will have trajectories (5) deviated towards a focal point (7).;With a positive potential of more than 30 V applied to said tip (1), and in a noble gas atmosphere, a beam of ions passing through the microlens of the invention will have trajectories (5) deflected towards said focal point (7).