Retarding-field differential-output energy prefilter for high-performance secondary ion mass spectrometry

Abstract

A retarding-field differential-output energy prefilter has been optically matched to a quadrupole mass spectrometer to produce a high-performance secondary ion quadrupole mass spectrometer. The sample area was designed to be field free to allow for sample charge compensation and to prevent secondary ion trajectories from being affected by electric fields. Design considerations for optically matching the energy prefilter to the quadrupole mass filter (QMF) are discussed. The overall transmission of the instrument was 1.8×10−4 at a mass resolution of 100 M/ΔM (1–100 amu range) for copper and 1.7×10−5 at a mass resolution of 400 M/ΔM (10–250 amu range) for tungsten.