Last updated at: (Beijing Time) Friday, December 26, 2003

Not a second error for China initiated cool-atomic fountain clock within 3.5m years

China has become a leading country in the world in the field of time frequency metrology.


The first laser cooled cesium atomic fountain clock has been successfully initiated by China National Institute of Metrology under the support of the Ministry of Science and Technology and China National Natural Science Foundation, according to the news released by Guangming Daily Dec.24. The accuracy of its time frequency is 8.5 x 10-15, which means not a second error happens in 3.5m years. The result passed the testing organized by China Administration of Quality Supervision, Inspection and Quarantine on Dec.24. Experts in charge of the testing, including Wang Daheng and Wang Yuzhu from the CAS agreed in unison the successful development of the clock marks that China has become one of the leading countries in the world in the field of the research on time frequency metrology after on-spot inspection of apparatus cooled by cesium atomic fountain.

Background: about the atomic clock
The primary clock is regarded as the source of a nation's independent time frequency system on which depends the nation's core interest. The high precision time frequency metrology based on the cesium atomic clock is widely applied in national defense, scientific research and various areas in the national economy. China National Institute of Metrology is the only institution in China, which has successfully developed, built and maintained the cesium atomic primary clock. This clock will become the new generation of our national time frequency reference. All the local time frequency reference around China should be in line with this clock. Now only France, the US and Germany have independently developed their own atomic primary clock of this kind before China.

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