A Correlational Analysis of the Effects of Changing Environmental Conditions on the NR Atomic Hydrogen Maser

R.A. Dragonette, J.J Suter

Abstract:	An extensive statistical analysis has been undertaken to determine if a correlation exists between changes in an NR atomic hydrogen maser's frequency offset and changes in environmental conditions. Data have been acquired over the past 20 months by recording the frequency offset of three NR atomic hydrogen masers along with the relative and absolute humidity, barometric pressure, and ambient temperature of the laboratory in which the masers are maintained. Correlational analyses have been performed comparing barometric pressure, humidity, and temperature with maser frequency offset as functions of time for periods ranging from 5.5 to 17 days. Semi partial correlation coefficients as large as -0.9 have been found between barometric pressure and maser frequenq offset for data covering periods as long as a week. Maser frequency offset and barometric pressure were consistently found to change simultaneously. The correlation between humidity and frequency offset is less predictable, and the resulting semi partial correlation coefficients were usually small when compared with those derived from the relationship between pressure and frequency offset. The time delay between changes in humidity and correlated changes in maser frequency offset was found to vary extensively with no predictable pattern. Analysis of temperature data indicates that, in the most current design, temperature does not significantly affect maser frequency offset in the laboratory environment. Thus, the results of the analyses disclose a significant statistical correlation between changes in maser frequency offset and changes in barometric pressure. The statistics also reveal some correlation between humidity and frequency offset, but for reasons to be discussed, the effects of humidity should be considered secondary to the effects of changing barometric pressure.
Published in:	Proceedings of the 23th Annual Precise Time and Time Interval Systems and Applications Meeting December 3 - 5, 1991 Pasadena, California
Pages:	287 - 295
Cite this article:	Dragonette, R.A., Suter, J.J, "A Correlational Analysis of the Effects of Changing Environmental Conditions on the NR Atomic Hydrogen Maser," Proceedings of the 23th Annual Precise Time and Time Interval Systems and Applications Meeting, Pasadena, California, December 1991, pp. 287-295.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In