GENERATION OF COMBINATION OF RF AND AXIAL DC ELECTRIC FIELDS IN AN RF-ONLY MULTIPOLE

摘要

An RF-only multipole includes a spiral resistive path formed around eachmultipole rod body. RF voltages are applied to the rod body and resistivepath, and DC voltages are applied to the resistive path, to create a radiallyconfining RF field and an axial DC field that assists in propelling ionsthrough the multipole interior along the longitudinal axis thereof. In oneimplementation, the resistive path takes the form of a wire of resistivematerial, such as nichrome, which is laid down in the groove defined betweenthreads formed on the rod body. The RF-only multipole of the invention avoidsthe need to use auxiliary rods or similar supplemental structures to generatethe axial DC field.