Patents by Inventor John D. Prestage

John D. Prestage 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).

  • Patent number: 8058936
    Abstract: An atomic ion clock with a first ion trap and a second ion trap, where the second ion trap is of higher order than the first ion trap. In one embodiment, ions may be shuttled back and forth from one ion trap to the other by application of voltage ramps to the electrodes in the ion traps, where microwave interrogation takes place when the ions are in the second ion trap, and fluorescence is induced and measured when the ions are in the first ion trap. In one embodiment, the RF voltages applied to the second ion trap to contain the ions are at a higher frequency than that applied to the first ion trap. Other embodiments are described and claimed.
    Type: Grant
    Filed: August 29, 2008
    Date of Patent: November 15, 2011
    Assignee: California Institute of Technology
    Inventors: John D. Prestage, Sang K. Chung
  • Publication number: 20090058545
    Abstract: An atomic ion clock with a first ion trap and a second ion trap, where the second ion trap is of higher order than the first ion trap. In one embodiment, ions may be shuttled back and forth from one ion trap to the other by application of voltage ramps to the electrodes in the ion traps, where microwave interrogation takes place when the ions are in the second ion trap, and fluorescence is induced and measured when the ions are in the first ion trap. In one embodiment, the RF voltages applied to the second ion trap to contain the ions are at a higher frequency than that applied to the first ion trap. Other embodiments are described and claimed.
    Type: Application
    Filed: August 29, 2008
    Publication date: March 5, 2009
    Applicant: CALIFORNIA INSTITUTE OF TECHNOLOGY
    Inventors: John D. Prestage, Sang K. Chung
  • Patent number: 6157031
    Abstract: The present invention describes a quadrupole mass analyzer with linear ion trap. The quadrupole mass analyzer functions in a dual-mode. A conventional transmission mode operates with external ionizer supplying ions to the quadrupole analyzer. In an ion trap mode, DC endcap electrodes are attached to the rf quadrupole cylinder to form a trapping chamber where ions are confined. The preferred mode is based on a segmented cylinder electrode geometry which produces a substantially quadrupolar field distribution as used in a conventional four-rod quadrupole mass analyzer. Electrodes are generated from a cylinder that has been segmented along its length into some number of electrically isolated electrodes.
    Type: Grant
    Filed: September 17, 1998
    Date of Patent: December 5, 2000
    Assignee: California Institute of Technology
    Inventor: John D. Prestage
  • Patent number: 5420549
    Abstract: A linear ion trap for frequency standard applications is provided with a plurality of trapping rods equally spaced and applied quadrupole rf voltages for radial confinement of atomic ions and biased level pins at each end for axial confinement of the ions. The trapping rods are divided into two linear ion trap regions by a gap in each rod in a common radial plane to provide dc discontinuity, thus dc isolating one region from the other. A first region for ion-loading and preparation/fluorescence is biased with a dc voltage to transport ions into a second region for resonance/frequency comparison with a local oscillator derived frequency while the second region is held at zero voltage. The dc bias voltage of the regions is reversed for transporting the ions back into the first region for fluorescence/measurement. The dual mode cycle is repeated continuously for comparison and feedback control of the local oscillator derived frequency.
    Type: Grant
    Filed: May 13, 1994
    Date of Patent: May 30, 1995
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventor: John D. Prestage