Abstract: An ion source assembly is described that includes an electron source configured to inject electrons into an ion volume to ionize an atom or molecule in the ion volume, wherein the electron source includes a filament. A lens electrode is positioned adjacent the electron source and includes an opening configured to pass electrons therethrough from the electron source into the ion volume. A supply voltage source is coupled to the filament and configured to supply a first voltage to the filament, wherein the first voltage is operable to ionize the molecules in the ion volume. Further, a bias voltage source is coupled to the supply voltage source and configured to supply a bias voltage to the lens electrode. Electrons striking the lens electrode are thereafter returned to the filament.

Abstract: An ion source assembly is described that includes an electron source configured to inject electrons into an ion volume to ionize an atom or molecule in the ion volume, wherein the electron source includes a filament. A lens electrode is positioned adjacent the electron source and includes an opening configured to pass electrons therethrough from the electron source into the ion volume. A supply voltage source is coupled to the filament and configured to supply a first voltage to the filament, wherein the first voltage is operable to ionize the molecules in the ion volume. Further, a bias voltage source is coupled to the supply voltage source and configured to supply a bias voltage to the lens electrode. Electrons striking the lens electrode are thereafter returned to the filament.

Abstract: A liquid chromatograph for HPLC utilizes low pressure solvent metering pumps for solvent mixing in series with a high pressure pump driving the column. Solvent mixture is provided at a flow based upon the intake demand of the high pressure pump. Such operation is obtained by the use of flow control apparatus disposed between the solvent metering pumps and the high pressure pump. The flow control apparatus includes a detector cell disposed in the solvent mixture flow path between the metering pumps and the high pressure pump. The cell has an inlet port for receiving an input flow of solvent mixture into the cell from the solvent mixing means, an outlet port for withdrawal of an output flow of solvent mixture by the high pressure pumps, and a reservoir between the inlet and outlet ports for holding a volume of solvent mixture accumulated in an amount dependent upon the relative flow rates of the cell input and output flow.