Electron multiplier having electron filtering
AssigneeAgilent Technologies, Inc.
InventorsAugust Hidalgo, Kenneth L Staton
Life of this patent
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Abstract
A system for detecting ions is disclosed. The system includes a detector having a plurality of dynodes arranged in an electron cascading configuration, and a power supply circuit electrically coupled to the plurality of dynodes. The plurality of dynodes include a first dynode and a second dynode. The power supply circuit is arranged to selectively adjust a potential difference between the first and second dynodes between a detection mode and a blanking mode. A method of detecting ions is also disclosed.
Claims24
An electron multiplier for detecting ion impact, the detector comprising:
- a plurality of dynodes arranged in an electron cascading configuration, the plurality of dynodes including at least a first dynode and a second dynode arranged to receive electrons from the first dynode and defining a path;
- a power supply circuit electrically coupled to the plurality of dynodes including the first and second dynodes, wherein the power supply circuit is arranged to selectively adjust a potential difference between the first and second dynodes between a first state in which the second dynode has a greater voltage than the first dynode and a second state in which the second dynode has a voltage substantially similar to or less than the first dynode.
A detector for detecting ion impact, the detector comprising:
- an ion source for ionizing a sample to generate ions;
- ion optics for receiving and focusing the ions from the ion source;
- an flight tube positioned to define an ion path for the ions from the ion optics;
- a plurality of dynodes in an electron cascading configuration and arranged to receive the ions from the ion path, the plurality of dynodes defining an electron path and comprising at least:
- a first dynode;
- a second dynode arranged to receive electrons from the first dynode;
- a third dynode arranged immediately upstream of the first dynode along the electron path to supply electrons to the first dynode;
- and
- a fourth dynode arranged immediately downstream of the second dynode along the electron path to receive electrons from the second dynode;
- and
- a power supply circuit electrically coupled to the plurality of dynodes, the power supply circuit comprising:
- a plurality of resistive elements, each resistive element electrically connected between adjacent dynodes of the plurality of dynodes arranged in the electron cascading configuration;
- a pulse generator electrically coupled to the second dynode to selectively adjust a potential difference between the first and second dynodes between a first state in which the second dynode has a greater voltage than the first dynode and a second state in which the second dynode has a voltage substantially similar to the first dynode;
- a first capacitive coupling electrically coupled between the power source and the third dynode to maintain a substantially constant third dynode voltage throughout the first state and the second state;
- and
- a second capacitive coupling electrically coupled between the fourth dynode and ground to maintain a substantially constant fourth dynode voltage throughout the first state and the second state.
A method of detecting ions from a sample, the method comprising:
- receiving ions from an ion source at an electron multiplier, the ions including at least a wanted constituent and an unwanted constituent;
- detecting impacts of the ions corresponding to the wanted constituent from the sample with a detector;
- and
- inhibiting detection of impacts of ions corresponding to the unwanted constituent from the sample.
Dependencies are inferred from the claim text.