NASA 1996 SBIR Phase I

PROJECT TITLE : A Flight Rated Time of Flight Mass Spectrometer with 10-15 Torr Sensitivity for insitu Thin Film Process Control

TECHNICAL ABSTRACT (LIMIT 200 WORDS)

Two flight rated low resolution time of flight mass spectrometers (TOFMS) have been used successfully on the flights of the wakeshield facility (WSF) funded through the NASA Space Vacuum Epitaxy Center at the University of Houston. These instruments measured the composition of the ultra vacuum which has been shown to form behind the wakeshield in low earth orbit. Recent flight data from the WSF-02 flight shows a vacuum of at least 10-11 Torr. However, a theoretically projected vacuum of less than 10-15 Torr could not be confirmed because of the 10-10 Torr sensitivity limitation of the mass spectrometer. Although these instruments were state of the art five years ago, several innovations in our laboratory have since appeared which could markedly increase the sensitivity of these TOFMS below the 10-14 Torr range and make the instrument far more rugged, reliable, and compact. Our phase I objective will be twofold.

We will modify the ionizer of the existing flight rated mass spectrometer to increase the sensitivity by four orders of magnitude. We will then design a new compact TOFMS which could be used not only in flight rated applications but also where portable instruments are required for environmental monitoring or bomb detection.

The proposed time of flight instrumentation fits perfectly into our line of TOF instruments for surface analysis and process control. The testing of the TOFMS in an MBE environment solves the immediate problem of quantitation of impurities during the WSF growth of thin films in low earth orbit, but it also is a perfect testbed for debugging an instrument which would retrofit to MBE chambers in commercial use now. The cost of TOF instrumentation has traditionally been in the complexity and cost of the electronics which would be solved in our design. Thus the phase II instrument would be price competitive with existing quadrupoles now in use for process control, but with the inherent higher performance of TOF.

J. Albert Schultz
Ionwerks
2472 Bolsover, Ste. 255
Houston, TX 77005

Ionwerks
2472 Bolsover, Ste. 255
Houston, TX 77005