Ion collecting electrode for total pressure collector

Abstract

A mass spectrometer gas analyzer includes an ion source for producing ions of a sample gas in a defined ion volume. An ion analyzer collects and analyzes a first portion of the produced ions to determine a partial pressure for a selected gas species within the sample gas. An oppositely disposed ion collector collects a second portion of the ions to determine a total pressure of the contained gas sample. A collecting surface of the ion collector is positioned relative to the incoming ion beam to allow collection of ion current but the surface is configured such that a substantial portion of a plurality of secondary electrons produced by ion bombardment with the ion collector are deflected away from the ionization volume. The partial pressure is thus determined by the ion analyzer without secondary electrons entering the ion analyzer.

Dependencies are inferred from the claim text.