Method for measuring ionic currents, and a catching device therefor
AssigneeThermo Finnigan Mat GmbH
InventorsHeinz Lerche, Johannes Schwieters
Life of this patent
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Abstract
The invention relates to a novel method for measuring ionic currents when determining isotope ratios and suing a mass spectrometer. Two or more ionic currents are measured in parallel, that is to say caught by catchers and evaluated via respectively assigned electronic measuring system. The assignments between catchers and electronic measuring systems are changed as time progresses.
Claims8
A method for measuring temporally constant signal ratios, in particular ionic currents for measuring isotope ratios, preferably by using a mass spectrometer, two or more signals being measured in parallel by a catching device having two or more catchers, and evaluated in a measuring device having two or more electronic measuring systems, characterized by the following features:
- a) subdividing the measurement into sequential time periods (measuring blocks);
- b) in a first time period, assigning a specific catcher to each electronic measuring system to collect first measurement values;
- c) changing the assignment of the catcher and electronic measuring system in the next time period to collect next measurement values so that each electronic measuring system is assigned to a different catcher than in the preceding time period;
- and
- d) evaluating the first and next measurement values.
The method for measuring temporally constant signals, in particular ionic currents for measuring isotope ratios, preferably by using a mass spectrometer, two or more signals being measured in parallel by a catching device having two or more catchers, and evaluated in a measuring device having two or more electronic measuring systems, characterized by the following features:
- a) subdividing the measurement into sequential time periods (measuring blocks);
- b) providing more measuring channels comprised of catchers and electronic measuring systems than measuring signals;
- c) in a first time period, feeding the signals from a first group of catchers to a first group of electronic measuring systems, while a second group of catchers receiving no signals and the group of electronic measuring systems connected thereto being calibrated, in particular, by measuring a base line;
- and
- d) in a second time period, feeding the signals from the first group of catchers to the second group of electronic measuring systems, while the first group of electronic measuring systems assigned to the second group of catchers being calibrated.
A measuring system for temporally constant signal ratios, in particular for parallel ionic currents, with two or more measuring channels each having a catcher and an electronic measuring system, characterized by a device (relay matrix) for alternately interconnecting the catchers and the electronic measuring systems in such a way that each electronic measuring system can alternately be connected to one or a plurality of catchers.
Dependencies are inferred from the claim text.