| Original Articles |
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Improvements and New Evaluation of NIM4 Caesium Fountain Clock at NIM in 2005--2006 |
| LI Tian-Chu;LI Ming-Shou;LIN Ping-Wei;WANG Ping;CHEN Wei-Liang;LIU Nian-Feng;LIN Yi-Ge |
| National Institute of Metrology (NIM), Beijing 100013 |
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| Cite this article: |
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LI Tian-Chu, LI Ming-Shou, LIN Ping-Wei et al 2007 Chin. Phys. Lett. 24 1177-1179 |
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Abstract The NIM4 caesium fountain clock has been operating stably and sub-continually since August 2003. We present our improvements on NIM4 in 2005--06 and the most recent evaluation for its frequency shifts with an uncertainty of 5×10-15. A 203-day comparison between NIM4 and GPS time shows an agreement of 2×10-14. Finally the construction of the NIM5 transportable caesium fountain clock is briefly reported.
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| Keywords:
06.30.Ft
43.58.Hp
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Received: 15 January 2007
Published: 23 April 2007
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| PACS: |
06.30.Ft
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(Time and frequency)
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43.58.Hp
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(Tuning forks, frequency standards; frequency measuring and recording instruments; time standards and chronographs)
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[1] 13th CGPM Resolution 1 (CR.103); SI unit of time (second)1968 Metrologia 4 41
[2] Clairon A, Laurent P, Santarelli G et al 1995 IEEEInstrum. Meas. 44 128
[3] Li T, Li M, Lin P et al 2004 Acta Metrologia Sin. 25 193 (in Chinese)
[4] Li T, Li M, Lin P et al 2004 UFFC-FCS 2004 (Montreal 23--27 August2004) p 431
[5] Li m, Li T, Lin P et al 2005 National Time & FrequencySymp. (Xian 1--3 November 2005) p 6
[6] Jefferts S, Shirley J, Parker T et al 2002 Metrologia 39 321 |
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