# US 2014/0151549 A1 · Ion detectors and methods of using them > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0151549 A1 - Document ID: US20140151549A1 - Status: Published application - Kind: A1 - Application number: 14/082,512 - Filed: 2013-11-18 - Published: 2014-06-05 - Earliest claimed: 2012-11-19 - Assignees: PerkinElmer Health Sciences, Inc. - Inventors: Urs Steiner; Daniel Robert Marshak - Web page: https://patentgrep.com/patent/US20140151549A1 ## CPC - H01J 43/18: Electrode arrangements using essentially more than one dynode - H01J 43/30: Circuit arrangements not adapted to a particular application of the tube and not otherwise provided for - H01J 49/025: {Detectors specially adapted to particle spectrometers (data acquisition H01J49/0036; detectors per se G01T, e.g. G01T1/28, G01T1/29)} - G01T 1/208: Circuits specially adapted for scintillation detectors, e.g. for the photo-multiplier section - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) - G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00) ## Abstract Certain embodiments described herein are directed to ion detectors and systems. In some examples, the ion detector can include a plurality of dynodes, in which one or more of the dynodes are coupled to an electrometer. In other configurations, each dynode can be coupled to a respective electrometer. Methods using the ion detectors are also described. ## Claims ### Claim 1 A mass spectrometer comprising: a sample introduction system; an ion source fluidically coupled to the sample introduction system; a mass analyzer fluidically coupled to the ion source; and a detector fluidically coupled to the mass analyzer, in which the detector comprises an electron multiplier comprising a plurality of dynodes each electrically coupled to a respective electrometer. ### Claim 2 (depends on 1) The mass spectrometer of claim 1, further comprising a first processor electrically coupled to each electrometer. ### Claim 3 (depends on 2) The mass spectrometer of claim 2, in which the first processor is configured to measure the input or output current at each respective dynode. ### Claim 4 (depends on 2) The mass spectrometer of claim 2, in which the first processor is configured to calculate a mean input current using received input current signals and using the gain of the respective dynode. ### Claim 5 (depends on 2) The mass spectrometer of claim 2, in which the first processor is configured to calculate a gain of a first dynode by comparing a current of the first dynode to a current of a dynode immediately upstream of the first dynode. ### Claim 6 (depends on 2) The mass spectrometer of claim 2, in which each electrometer is electrically coupled to a signal converter to provide simultaneous digital signals to the processor from each of the plurality of dynodes. ### Claim 7 (depends on 6) The mass spectrometer of claim 6, in which the signal converter comprises an analog-to-digital converter. ### Claim 8 (depends on 7) The mass spectrometer of claim 7, in which the detector further comprises a respective power converter electrically coupled to each electrometer and analog-to-digital converter pair. ### Claim 9 (depends on 2) The mass spectrometer of claim 2, in which the detector is configured to measure all dynode currents simultaneously. ### Claim 10 (depends on 2) The mass spectrometer of claim 2, in which the detector is configured to prevent a current overload at each dynode. ### Claim 11 (depends on 10) The mass spectrometer of claim 10, in which the detector is configured to alter the voltage at a saturated dynode or a dynode downstream from the saturated dynode. ### Claim 12 (depends on 11) The mass spectrometer of claim 11, in which the detector is configured to invert the polarity of the voltage of the downstream dynode. ### Claim 13 (depends on 10) The mass spectrometer of claim 10, in which the detector is configured to prevent any substantial secondary electron emission from a downstream dynode adjacent to the dynode where the saturation current is detected. ### Claim at position 14 14-16. (canceled) ### Claim 17 (depends on 1) The mass spectrometer of claim 1, in which dynode to dynode voltage is substantially constant with a change of electron current at each dynode. ### Claim 18 (depends on 1) The mass spectrometer of claim 1, in which dynamic range of ion current measurement is greater than 1010 for a 100 KHz reading. ### Claim 19 (depends on 2) The mass spectrometer of claim 2, in which the first processor is configured to calculate a mean electron multiplier input current by calculating input currents at all dynodes and discarding calculated input currents below a noise current and above a saturation current. ### Claim 20 (depends on 19) The mass spectrometer of claim 19, in which the first processor is configured to scale each non-discarded calculated input currents using the respective electron multiplier gain and average the scaled input currents to provide the mean electron multiplier input current. ### Claim 21 A mass spectrometer comprising: a sample introduction system; an ion source fluidically coupled to the sample introduction system; a mass analyzer fluidically coupled to the ion source; and a detector fluidically coupled to the mass analyzer, in which the detector comprises a single-stage electron multiplier comprising a plurality of dynodes, in which at least one internal dynode of the plurality of dynodes is electrically coupled to an electrometer. ### Claim 22 (depends on 21) The mass spectrometer of claim 21, further comprising at least one additional electrometer electrically coupled to one of the plurality of dynodes. ### Claim 23 (depends on 22) The mass spectrometer of claim 22, further comprising a first processor electrically coupled to each electrometer and configured to measure the input or output current into each respective dynode. ### Claim at position 22 24-133. (canceled)