AVS 56th International Symposium & Exhibition
    Vacuum Technology Monday Sessions
       Session VT-MoA

Paper VT-MoA6
A Practical Electrostatic Ion-Trap Sensor

Monday, November 9, 2009, 3:40 pm, Room C1

Session: Pressure, Partial Pressure, and Flow Measurement
Presenter: G.A. Brucker, Brooks Automation, Inc.
Authors: G.A. Brucker, Brooks Automation, Inc.
J. Rathbone, Brooks Automation, Inc.
S. Blouch, Brooks Automation, Inc.
M. Schott, Brooks Automation, Inc.
K. Van Antwerp, Brooks Automation, Inc.
Correspondent: Click to Email
We have expanded upon the work of A.V. Ermakov and B.J. Hinch from Rutgers University to further develop a novel electrostatic ion trap sensor that is based upon the principles of autoresonant ion-ejection and detection for use in low mass range mass spectrometry applications. The improved sensor is approximately 15 cm in length, with a 2.5 cm ion-trap component capable of scanning a mass range of 1-300amu with a mass resolving power of >130x. A symmetric RF pumping scheme combined with a custom RF frequency sweep profile provide simplified electrical design along with optimal ion ejection efficiency across the entire mass range. A novel dual-filament, off-axis ionization scheme provides both pressure range and detection limit enhancements. The entire structure that includes the ionizer, mass analyzer and detector were integrated into a pre-existing Stabil-Ion® gauge total pressure ionization sensor envelope. The improved sensor retained many of the benefits of the original concept sensor such as a rapid sensor scanning speed approximately 70ms for 1-100amu scans and a mW RF ion-trap drive requirement that allows for a remote gauge cable connection to the controller electronics. The simple structure and intelligent electronics were implemented to allow for self- calibration of partial pressure measurements and automated recalibration of the electron multiplier detector. A novel dual-filament ionization source design was incorporated into the ion trap to allow fast and easy field replacement of filaments.