Patents by Inventor Craig A. Walla

Craig A. Walla 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).

  • Methods and apparatus to control charge neutralization reactions in ion traps
    Patent number: 6674067
    Abstract: An ion trap mass spectrometer uses electrospray ionization to introduce multiply-charged positive ions in an axial direction into a quadrupole ion trap and glow discharge ionization to introduce singly-charged negative ions in a radial direction into the ion trap. Methods of controlling ion-to-ion charge transfer reactions include applying a combination of a dipolar DC voltage and a dipolar RF voltage across endcap electrodes to allow partial charge state neutralization reactions to occur between the positive and negative ions and then control suspension and resumption of further charge state neutralization reactions. The remaining ions can be further processed and transformed and a mass spectrum created by scanning a quadrupolar RF field.
    Type: Grant
    Filed: July 2, 2002
    Date of Patent: January 6, 2004
    Assignee: Hitachi High Technologies America, Inc.
    Inventors: Peter B. Grosshans, Chad M. Ostrander, Craig A. Walla
  • Methods and apparatus to control charge neutralization reactions in ion traps
    Publication number: 20030155502
    Abstract: An ion trap mass spectrometer uses electrospray ionization to introduce multiply-charged positive ions in an axial direction into a quadrupole ion trap and glow discharge ionization to introduce singly-charged negative ions in a radial direction into the ion trap. Methods of controlling ion-to-ion charge transfer reactions include applying a combination of a dipolar DC voltage and a dipolar RF voltage across endcap electrodes to allow partial charge state neutralization reactions to occur between the positive and negative ions and then control suspension and resumption of further charge state neutralization reactions. The remaining ions can be further processed and transformed and a mass spectrum created by scanning a quadrupolar RF field.
    Type: Application
    Filed: July 2, 2002
    Publication date: August 21, 2003
    Inventors: Peter B. Grosshans, Chad M. Ostrander, Craig A. Walla
  • Methods and apparatus to control charge neutralization reactions in ion traps
    Patent number: 6570151
    Abstract: An ion trap mass spectrometer uses electrospray ionization to introduce multiply-charged positive ions in an axial direction into a quadrupole ion trap and glow discharge ionization to introduce singly-charged negative ions in a radial direction into the ion trap. Methods of controlling ion-to-ion charge transfer reactions include applying dipolar DC voltage across endcap electrodes to allow partial charge state neutralization reactions to occur between the positive and negative ions and then suspending further charge state neutralization reactions. The remaining ions can be further processed and transformed and a mass spectrum created by scanning a quadrupolar RF field.
    Type: Grant
    Filed: February 21, 2002
    Date of Patent: May 27, 2003
    Assignee: Hitachi Instruments, Inc.
    Inventors: Peter B. Grosshans, Chad M. Ostrander, Craig A. Walla