Thermo Finnigan LLC

Thermo Fisher Scientific Gmbh

Thermo Finnegan LLC

Oleg Silivra

Harald Oser

Jae C Schwartz

Alan E Schoen

Joshua T Maze

Terry N Olney

Linfan Li

Johnathan Wayne Smith

Mikhail V Ugarov

Mark E Hardman

Berg A Tehlirian

A method of ion detection comprises: (a) setting electrical potentials of a dynode and a scintillator electrode of a Daly detector and of a focusing lens disposed at an ion inlet of the Daly detector so as to detect negatively charged ions received from a mass analyzer or mass filter; (b) transferring the negatively charged ions from the mass analyzer or mass filter to the Daly detector through the lens and detecting said negatively charged ions by a photodetector of the Daly detector; (c) setting electrical potentials of the dynode, the scintillator electrode and the focusing lens of the Daly detector so as to detect positively charged ions received from the mass analyzer or mass filter; and (d) transferring the positively charged ions from the mass analyzer or mass filter to the Daly detector through the lens and detecting said positively charged ions by the photodetector.

Daly detector operable in negative ion and positive ion detection modes

A metal-channel conversion dynode comprises: a wafer comprising a first face and a second face parallel to the first face and having a thickness less than 1000 μm; and a plurality of channels passing through the wafer from the first face to the second face at an angle to a plane of the first face and a plane of the second face. In some embodiments, each inter-channel distance may be substantially the same as the wafer thickness. In some embodiments, the wafer is fabricated from tungsten. In some other embodiments, the wafer comprises a non-electrically conductive material that is fabricated by three-dimensional (3D) printing or other means and that is coated, on its faces and within its channels, with a metal or suitably conductive coating that produces secondary electrons upon impact by either positive or negative ions.

Ion-to-electron conversion dynode for ion imaging applications

An ion detector that can detect either positive or negative ions comprises: an ion inlet comprising an ion focusing lens; a dynode having a surface configured to intercept, within a zone of interception, a stream of ions passing through the ion focusing lens, wherein a plane that is tangent to the dynode surface at the zone of interception is disposed at an angle to a line that passes through the center of the dynode surface and the center of the focusing lens; a scintillator having a surface that is configured to receive secondary electrons emitted from the zone of interception; a scintillator electrode affixed to the scintillator surface; a photodetector configured to receive photons emitted by the scintillator and to generate an electric signal in response thereto; and one or more power supplies electrically coupled to the focusing lens, the dynode, the scintillator electrode and the photodetector.

A mass spectrometer includes an ion source configured to ionize a sample to produce ions; a mass analyzer configured to separate the ions based on their mass-to-charge ratio; a detector configured to detect ions; an ion optics component configured to direct ions along at least part of the path from the ion source to the mass analyzer to the detector; and a controller. The controller is configured to switch the source at a first time from a first polarity source voltage to a second polarity source voltage; and switch the detector or the ion optics component at a second time from a first voltage to a second voltage, the second time being offset from the first time, the first voltage being the first polarity detector voltage or the first polarity ion optics voltage and the second voltage being the second polarity detector voltage or the second polarity ion optics voltage.

Dual polarity ion management

An electrospray ion source comprises: a needle capillary comprising a spray tip end and an opposite end; a nebulizing gas channel parallel to the needle capillary; an auxiliary gas channel parallel to the needle capillary; a heater parallel to a length of the auxiliary gas channel; a thermally conductive heat transfer member parallel to a length of the needle capillary and disposed between the needle capillary and the heater, said heat transfer member having a first end adjacent to the spray tip end of the needle capillary and a second end opposite to the first end; and a cooled heat sink member in thermal contact with the second end of the heat transfer member.

Apparatus and system for active heat transfer management in ESI ion sources

A mass spectrometry method comprises: introducing a first portion of a sample of ions including precursor ions comprising a first precursor-ion mass-to-charge (m/z) ratio into a first mass analyzer; transmitting the precursor ions from the first mass analyzer to a reaction or fragmentation cell such that a first population of product ions are continuously accumulated therein over a first accumulation time duration; initiating release of the accumulated first population of product ions from the reaction or fragmentation cell; continuously transmitting the released first population of product ions from the reaction cell to a second mass analyzer; transmitting a portion of the released first population of product ions comprising a first product-ion m/z ratio from the second mass analyzer to a detector; and detecting a varying quantity of the product ions having the first product-ion m/z ratio for a predetermined data-acquisition time period after the initiation of the release.

Method for mass spectrometer with enhanced sensitivity to product ions

Method for operating a mass spectrometer includes supplying a quantity of ions to an ion detector. The ion detector can include a conversion dynode operating in a first polarity and an electron multiplier. The method further includes adjusting the gain of the electron multiplier to determine a first set of calibration parameters, and calculating a second set of calibration parameters for the electron multiplier from the first set of calibration parameters. The second set of calibration parameters are for a second polarity of the conversion dynode. The method can further include configuring the ion detector to operate at the second polarity based on the second set of calibration parameters, and supplying ions of the second polarity to the mass spectrometer, and detecting an ion at a particular mass to charge ratio using the ion detector.

Systems and methods for calibrating gain in an electron multiplier

A collision cell has a plurality of rod electrodes arranged in opposed pairs around an axial centerline and a plurality of drag vanes arranged in the interstitial spaces between the rod electrodes. Operating the collision cell includes, applying a rod offset voltage to the rod electrodes, and varying an offset voltage applied to the drag vanes to identify a vane offset voltage with a maximum intensity for the transition. The method further includes varying a drag field by adjusting the voltages applied to drag vane terminals in opposite directions to identify a drag field value with a cross talk below a cross talk threshold, varying the vane offset voltage by adjusting the voltages applied to the drag vane terminals to maximize the intensity of the transition while preserving the drag field, and operating the collision cell at the vane offset voltage and drag field to monitor the transition.

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Milpitas, CA, United States of America

Oleg Silivra