Abstract: A combined ion discharge tube and an ion guide system is disclosed. The ion discharge tube comprises of a cathode tube and an anode surface. The discharge tube acts as the cathode, whereas the anode can be any number of different configurations. In one embodiment the discharge tube is set inside a quadrupole ion guide, with the walls of the ion guide being the anode. In other embodiments, the discharge tube is placed inside the rods of the quadrupole and the inner walls of the rods or a separate plate acting as the anode. In all configurations, the ions are formed by the discharge tube and are introduced into the RF confinement of an ion guide to increase ion transfer efficiency.

Abstract: The present invention is ion detection method for mass spectrometer. An electron multiplier is coupled with a conversion dynode for the detection of positive and negative ions. The aperture of the present system is ungrounded. As the ions (positive or negative) approach and go through the aperture, they induce an image current into the aperture plate which can be amplified and measured by a processing circuit. The magnitude of the image current is directly proportional to the number density, speed, charge, and polarity of ions flowing through the aperture. The measured image current is used as a means to switch between various detection modes. The measured current is calibrated and used as a reference to automatically switch between analog/counting modes, positive/negative ion detection, or various types of detectors implemented in the ion detection system.