Patent ID: 6847043

Claim:
An ion source comprising an ionisation chamber within which a plasma can be generated, the chamber having an outlet through which ions can exit from the ionisation chamber, electrodes in the ionisation chamber for establishing and maintaining a plasma within the chamber when a power supply is provided thereto, and a heat shield enclosing at least a part of the ionization chamber to retain heat within the chamber when the ion source is functioning, wherein the heat shield comprises a plurality of heat shield members which extend around the ionization chamber in spaced relationship thereto and a plurality of coupling members for connecting the heat shield members to form the heat shield around the ionization chamber, and wherein the ionization chamber is of cuboid shape and has side and end walls and the heat shield members are arranged in spaced relationship to said side and end walls, and wherein the coupling members are mounted adjacent intersections of side and end walls of the ionization chamber and each coupling member comprises a pillar portion extending parallel to and spaced from its adjacent intersection and wing portions extending in the general direction of the adjacent wall, the wing portions providing said slots to accommodate therebetween the spaced parallel plates of the associated heat shield member.