The USNO rubidium fountains
Abstract
Four rubidium fountains at the U.S. Naval Observatory (USNO) have been in operation for 4.5 years. Each fountain has demonstrated periods of stability marked by Total or Theo deviation below 10^-16. Occasional frequency changes, on order of 1.5 times per year per fountain, introduce deviations from white-frequency noise behavior. Averaged together, the four fountains form an ensemble with a white-frequency noise level of 10^-13 and excellent long-term stability as compared to the primary frequency standards contributing to TAI. Progress on using the clocks at USNO for improving limits on coupling of fundamental constants to gravity by measuring the universality of the gravitational redshift for different types of clocks is discussed.
Cite
@article{arxiv.1607.06776,
title = {The USNO rubidium fountains},
author = {Steven Peil and James Hanssen and Thomas B. Swanson and Jennifer Taylor and Christopher R. Ekstrom},
journal= {arXiv preprint arXiv:1607.06776},
year = {2016}
}
Comments
8th Symposium on Frequency Standards and Metrology 2015