Atomic Hydrogen Maser Development at the National Research Council of Canada

Abstract

Design and performance of two atomic hydrogen masers constructed a t the National Research Council, Ottawa, Canada, are discussed. Measurements are given of the relative stability of the two masers for periods from 10 sec to 3 weeks, and the maser frequencies related to that of the NRC long cesium beam frequency standard over a 41 day period. The latter measurements are related to other cesium frequency standards in the United States and Canada. The best stability for a single maser was found to be about 1 Y 10-14 for averaging periods of 1 h over a 24 h period.* To be published.

Some possibilities for laboratory searches for variations of fundamental constants

“…Most experiments [99,100,101,102] were devoted to a measurement of the maser frequency, while previously measured value for the wall-shift using another maser in Ref. [112] was accepted.…”

“…The first results with an accuracy of about 10 12 were reached about 35 years ago and some of them are presented in Table14. Most experiments[99,100,101,102] were devoted to a measurement of the maser frequency, while previously measured value for the wall-shift using another maser in Ref [112]. was accepted.…”

Characterization of frequency stability

“…Translations among the various stability measures for common noise types are possible, but there are significant reasons for choosing N = 2 and T = t for the preferred measure of frequency stability in the tirae domain. This measure, the Allan Variance, (N = 2) has been referenced by [12,[20][21][22], and more.…”

Some possibilities for laboratory searches for variations of fundamental constants

“…In Ref. [101] no explicit value of uncertainty was claimed. From discussions in that paper we estimate it as 3 · 10 −12 for the NRC cesium standard and 1.…”