GeezerVison

Release time: December 25, 2019

After conquering a series of obstacles of key techniques such as cold atom preparation, cooling and detection, ultra-stable microwave generation, NIM has successfully developed the primary standard cesium fountain clock - NIM6, and an ultra-stable microwave source. The frequency uncertainty of NIM6 is better than 5.8E-16, which means the clock will not gain or lose 1 second in 54 million years. 

The project provides measurement support for the generation, maintenance, improvement, and comparison of the standard time scale of the time frequency system of Beijing National Administration of GNSS and Applications (CNAGA). Two portable calcium ion clocks from the Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, two rubidium fountain clocks from the Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences and HUA CREATE, and some domestically developed small cesium clocks from Beijing University and other institutes were transported to NIM for frequency measurement and comparison. It is of great significance to build an independent, accurate and reliable time and frequency system in China.

Fig. NIM 6