The role of long-term lamp fluctuations in the random walk of frequency behavior of the rubidium frequency standard: A case study

Abstract

A long-term frequency stability test has been performed on an EG&G prototype Rb atomic frequency standard. In addition to this test revealing excellent performance for a Rb atomic clock, some classic Rb clock behaviors were also observed; namely, long-term frequency drift, spontaneous frequency jumps, and random walk of frequency noise for long averaging times. By careful analyses of the complete test record, we have found that the spontaneous frequency jumps and the random walk of frequency noise can be attributed to the behavior of the clock’s discharge lamp. The long-term frequency drift, however, was found not to be primarily lamp related. Although results of only a single test on a single Rb clock are reported here, we believe that the results are applicable to the Rb clock technology as a whole.