Zobrazeno 1 - 10
of 33
pro vyhledávání: '"Thomas B. Swanson"'
Publikováno v:
Metrologia. 54:247-252
The fundamental limits of atomic fountains as operational clocks are considered. Four rubidium fountains in operation at the US Naval Observatory for over 5.5 years have demonstrated unprecedented long-term stability for continuously running clocks (
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::db24df99090e8413451609aad3ae3d85
https://doi.org/10.1088/1681-7575/aa65f7
https://doi.org/10.1088/1681-7575/aa65f7
Publikováno v:
2018 IEEE International Frequency Control Symposium (IFCS).
Despite the remarkable progress in optical frequency standards over the past decade, the path toward continuously operating optical clocks remains challenging. We are investigating the prospect of achieving good long-term stability with a thermal ato
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::04b1577fa228e8609ac61069bf851d67
https://doi.org/10.1109/fcs.2018.8597569
https://doi.org/10.1109/fcs.2018.8597569
We have characterized the molecular tellurium (Te$_2$) spectrum in the vicinity of the 423nm $^1S_0-^1P_1$ and the 431nm $^3P_1-^3P_0$ transitions in neutral calcium. These transitions are relevant to optical clocks for atomic-beam characterization a
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e31b097418593d9bd3d2f9766211bd88
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
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f8204a61ad1f73f5efcb10b5f61e9d02
An ensemble of rubidium atomic fountain clocks has been put into operation at the U.S. Naval Observatory (USNO). These fountains are used as continuous clocks in the manner of commercial cesium beams and hydrogen masers for the purpose of improved ti
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::8aa7f6ebd3ac48c8a994529dec5b327d
http://arxiv.org/abs/1406.1376
http://arxiv.org/abs/1406.1376
Publikováno v:
2014 IEEE International Frequency Control Symposium (FCS).
Four rubidium fountains have been in continuous operation at USNO for more than 3 years. They contribute to the local timescale and are reported to the BIPM as continuously running clocks - as opposed to secondary standards - the first and only cold-
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::4f5d91f3cb6b38d2bcaa2ca063f37e2d
https://doi.org/10.1109/fcs.2014.6859969
https://doi.org/10.1109/fcs.2014.6859969
Tests of local position invariance (LPI) made by comparing the relative redshift of atomic clocks based on different atoms have been carried out for a variety of pairs of atomic species. In most cases, several absolute frequency measurements per year
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ef0b797614721970de898f9d30c87690
http://arxiv.org/abs/1301.6145
http://arxiv.org/abs/1301.6145
Four rubidium fountains have been in operation for the past 1.2 years at USNO. Individual fountain performance, applications to timekeeping and to tests of Local Position Invariance are presented.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::4e30d8ab44e839e4092784b75d2d9a6c
https://doi.org/10.21236/ada566333
https://doi.org/10.21236/ada566333
Publikováno v:
2011 Joint Conference of the IEEE International Frequency Control and the European Frequency and Time Forum (FCS) Proceedings.
Performance of the first two operational rubidium fountains at the USNO is presented using relative measurements and comparisons against other timescales. Recent results with four fountains indicate frequency agreement at the 10−15 level and good a
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::c6ba47935c08e5792f50d8369f724e39
https://doi.org/10.1109/fcs.2011.5977842
https://doi.org/10.1109/fcs.2011.5977842
Publikováno v:
2007 IEEE International Frequency Control Symposium Joint with the 21st European Frequency and Time Forum.
We have carried out stability comparisons between our rubidium fountain, built as a prototype for a continuously operating clock, and the USNO Maser Mean timescale. Long, continuous runs of the prototype system allow us to demonstrate fractional freq
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::48c8aac90e1d1829457bfb03c582a979
https://doi.org/10.1109/freq.2007.4319119
https://doi.org/10.1109/freq.2007.4319119