Characterization of a hybrid ion trap

A new ion trap is constructed of a cylindrical ring electrode and hyperbolic end caps. The premise is to determine the effect ring electrode geometry has on the operation of the ion trap. A model for the potential and electric field within the trap is developed. The model is used to show how adjusting the geometric parameters of the cell could be used to reduce the presence of higher order fields or optimize other desired properties. The stability diagram is mapped experimentally and using the standard definition for q(z), the q(eject) was determined to be 0.76. A proposed modification for the definition of q(z), which adjusts for the shape of the cylindrical ring electrode, results in a q(eject) of 0.93. The trap is shown to have a linear scanning relationship, resolved isolation and unit mass resolution. (Int J Mass Spectrom 190/191 (1999) 47-57) (C) 1999 Elsevier Science B.V.