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Proceedings Paper

High-sensitivity real-time NVR monitor
Author(s): William D. Bowers; Raymond L. Chuan
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Paper Abstract

The use of a temperature-controlled 200-MHz SAW resonator piezoelectric mass microbalance to monitor the mass of nonvolatile residue (NVR) deposited on its surface in real time is reported. The fundamental frequency of this device is mainly dependent on the configuration of the transducers and not on the thickness of the substrate. Therefore, higher operating frequencies can be achieved without reducing the thickness of the crystal. The real-time instrument was integrated onto a conventional stainless steel NVR plate and operated flawlessly over a 14-d period at Kennedy Space Center and successfully measured less than 1 ng/sq cm d NVR contamination. Contamination episodes detected by the instrument were correlated with scheduled activities on the test stand. Under the assumption of a baseline noise level of +/- 2 Hz, the absolute mass lower limit of detection would be 0.065 ng/sq cm. This would enable the detection of a daily NVR deposition rate of less than 0.1 ng/sq cm d.

Paper Details

Date Published: 18 December 1992
PDF: 8 pages
Proc. SPIE 1754, Optical System Contamination: Effects, Measurement, Control III, (18 December 1992); doi: 10.1117/12.140745
Show Author Affiliations
William D. Bowers, Femtometrics (United States)
Raymond L. Chuan, Femtometrics (United States)

Published in SPIE Proceedings Vol. 1754:
Optical System Contamination: Effects, Measurement, Control III
A. Peter M. Glassford, Editor(s)

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