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Session P1: Time Scales and Laboratory Activities

First Experiments on Application of Rb Fountain Frequency Standards in Russian State Time and Frequency Standard Laboratory for TA(SU) Time Scale Maintenance
I. Blinov, A. Boyko and N. Kosheliaevskii, VNIIFTRI Department of Metrology for Time and Space, Russia
Location: Regency B

At last PTTI meeting, PTTI’17, we mentioned that VNIIFTRI has got four Rb fountain frequency standards [1], which run as frequency standards, not clocks. These in-struments are not intended for secondary presentation of time unit the second SI. These are indeed very stable frequency reference without frequency drift inherent, for example, to H-masers. During last year output frequency of these standards has been calibrated against operational CsF02 primary fountain frequency standard and now one may use these instruments as time and frequency unit keepers.
This report will present very preliminary results of the first experiments on application of Rb fountain frequency standards for maintenance the national atomic time scale TA(SU). According internal regulation TA(SU) is independent atomic time scale with the unit of time the second SU, reproduced by operational primary Cs fountain frequency standards. This time scale by-turn is maintained by ensemble of continuously operating high stable hydrogen masers. On other hand, each H-maser demonstrate more or less pre-dictable frequency drift the value of which may be quite comparable to daily H-maser frequency stability. That is why one has times to times re-evaluate H-maser output frequency parameters. The more often one will re-evaluate H-maser output frequency param-eters the more stable and accurate (in sense unit of time the second SU) time scale will be produced.
The key problem is interruptible Cs primary fountain frequency standard mode of operation. Typically, Cs primary fountain frequency standard produces two or three ses-sions per month, but sometimes happens gaps for a some months. In such cases availabil-ity of more or less continuously operating stable and none drifting frequency reference such as Rb fountain frequency standards may a solution of the problem.
The paper will present comparisons of some scenarios of TA(SU maintenance: a. purely based on H-maser ensemble and primary Cs fountain frequency standards data and b. based on H-maser ensemble and single/ensemble of Rb fountain frequency standards data.
References
[1] Blinov I., Domnin Yu., Donchenko S., Goncharov A., Kosheliaevskii N., Naumov A., Slyusarev S., Russian State Time and Frequency Standard Laboratory Activi-ties and Updates, Proceedings of the 48th Annual Precise Time and Time Interval Systems and Applications Meeting, (PTTI 2017), January 30-February 02, 2017, Hyatt Regency Monterey, Monterey, California, USA.



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