Process and apparatus for measuring charge quantity flowing in a vacuum
AssigneeBalzers Aktiengesellschaft
InventorsWaelchli Urs, Stoeckli Armin Leo, Boesch Martin
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Abstract
For measuring the charge transported in an ion or electron beam, collecting grids are provided in a cascaded manner and the galvanic currents occurring there are measured. The same surface range is measured on the collecting cascade with respect to the particle current in the vacuum. The process and apparatus have particular applicability in partial-pressure and total-pressure measuring apparatuses, e.g. mass spectrometers and Bayard-d'Alpert tubes.
Claims19
A process for measuring electric charge quantity which flows per unit time through a vacuum volume range in a given direction, comprising the steps of
- arranging at least two collectors one behind another in the given direction so as to form a collector arrangement of independent measuring collectors each of which is configured to provide a galvanic current to a measuring circuit and at least one of which is provided with a collector surface which permits transmission of charge-transporting particles to a collector arranged downstream thereof in the given direction, and
- simultaneously collecting the charge-transporting particles in the given direction.
A measuring apparatus for measuring a charge quantity flowing through a vacuum volume range per time unit in a given direction, comprising a collector arrangement arranged in a vacuum and a galvanic current measuring circuit operatively connected with said collector arrangement, said collector arrangement comprising at least two collectors having collector surfaces which are arranged, as viewed in the given direction, behind the other, said collectors being connected to respective current inputs of said measuring circuit to form independent measuring collectors, the collector surface of an upstream one of the collectors, as viewed in the given direction, being configured to transmit charged particles therethrough towards a collector of the downstream one.
Dependencies are inferred from the claim text.