Patents by Inventor Lawrence Campbell

Lawrence Campbell has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20140353491
    Abstract: Methods and systems for creating a region for ion-ion reactions within a mass spectrometer are described. In various aspects, the methods and systems can confine a first group of ions in a sub-volume of a multipole ion trap, and introduce a second group of oppositely-charged ions into the multipole ion trap while maintaining the first group of ions within the sub-volume. In various embodiments, the methods and systems can operated at reduced pressures.
    Type: Application
    Filed: December 6, 2012
    Publication date: December 4, 2014
    Applicant: DH Technologies Development Pte,Ltd.
    Inventors: James Hager, John Lawrence Campbell
  • Publication number: 20140357502
    Abstract: In a first location of a mass spectrometer, a plurality of ionized molecules of an ion source are selected that have mass-to-charge ratios within a mass-to-charge ratio window width. The plurality of selected ionized molecules are transmitted from a first to a second location. Reagent ions are transmitted to the second location to reduce a charge state of one or more of the plurality of selected ionized molecules. A mass analyzer is used to analyze the plurality of reduced ionized molecules and produce a mass spectrum. A compound is identified from a peak of the spectrum that has a mass-to-charge ratio less than or equal to the highest mass-to-charge ratio in the window width if the noise is multiply charged and greater than the highest mass-to-charge ratio in the window width if the noise is singly charged.
    Type: Application
    Filed: November 28, 2012
    Publication date: December 4, 2014
    Inventors: John Lawrence Campbell, Yves Le Blanc, Alexandre V. Loboda, Igor Chernushevich
  • Patent number: 8890062
    Abstract: An apparatus and method are provided for analyzing samples of molecules. The apparatus comprises a mass analysis system including a differential mobility spectrometer, which includes at least three filter electrodes defining two ion flow paths where the filter electrodes generate electric fields for passing through selected portions of the sample ions based on the mobility characteristics of the sample ions. The differential mobility spectrometer also includes a voltage source that provides DC and RF voltages to at least one of the filter electrodes to generate the electric field, a first and a second ion inlet that receive sample ions, and an ion outlet that outputs the selected portion of the sample ions. A mass spectrometer receives some or all of the selected portion of the sample ions.
    Type: Grant
    Filed: November 21, 2012
    Date of Patent: November 18, 2014
    Assignee: DH Technologies Development Pte. Ltd.
    Inventors: John Lawrence Campbell, Yves LeBlanc
  • Publication number: 20140264009
    Abstract: An apparatus and method are provided for analyzing samples of molecules. The apparatus comprises a mass analysis system including a differential mobility spectrometer, which includes at least three filter electrodes defining two ion flow paths where the filter electrodes generate electric fields for passing through selected portions of the sample ions based on the mobility characteristics of the sample ions. The differential mobility spectrometer also includes a voltage source that provides DC and RF voltages to at least one of the filter electrodes to generate the electric field, a first and a second ion inlet that receive sample ions, and an ion outlet that outputs the selected portion of the sample ions. A mass spectrometer receives some or all of the selected portion of the sample ions.
    Type: Application
    Filed: November 21, 2012
    Publication date: September 18, 2014
    Applicant: DH Technologies Development Pte. Ltd.
    Inventors: John Lawrence Campbell, Yves LeBlanc
  • Publication number: 20060215492
    Abstract: A system for measuring distance in a gas or liquid operating medium has an even number of ultrasonic signal transmitters (12, 14), and a single ultrasonic signal receiver (16). The ultrasonic signal transmitters are adapted to transmit ultrasonic signals to a target (18) in the operating medium. Each of the transmitters and receiver are so spaced apart in a geometrically symmetrical planar array within an acoustically attenuating substrate medium, and each of the transmitted ultrasonic signals are so pulse driven in an acoustically symmetrical relationship, that opposing ultrasonic signals transmitted through the substrate medium by symmetrically opposed transmitters are cancelled at the receiver and a signal for measuring distance to the target is formed at the receiver by combination of the transmitted signals through the operating medium.
    Type: Application
    Filed: January 25, 2006
    Publication date: September 28, 2006
    Inventor: Lawrence Campbell
  • Patent number: 5384029
    Abstract: An electrochemical membrane sensor 20 for immersion in a test fluid, such as wastewater, is used to sense desired chemical species, such as dissolved oxygen, within the test fluid. The sensor 20 has an open housing that defines a chamber 24. The chamber 24 is sealed from the test fluid by a membrane 28, so that the chamber 24 can be filled with an electrolytic medium 30. The membrane 28 is selectively permeable so as to allow only the desired chemical species from the test fluid to permeate into the electrolytic medium. Spaced apart within the chamber 24 is a cathode 29 and an anode 29a which are electrically connected to a measurement transducer that responds to current between the cathode 29 and anode 29a. The current is proportional to the concentration of the desired chemical species within the test fluid.
    Type: Grant
    Filed: October 15, 1993
    Date of Patent: January 24, 1995
    Inventor: Lawrence A. Campbell