Study on the usage of hydrogen clock in time keeping

QU Li-li^1,2

(1. National Time Service Center, Chinese Academy of Sciences, Xi′an 710600, China;

2. Key Laboratory of Time and Frequency Primary Standards, National Time Service Center,

Chinese Academy of Sciences, Xi′an 710600, China)

Abstract: Based on the second difference of the measured time-difference for the hydrogen clock, the frequency drift of hydrogen clock can be estimated and corrected. The corrected data for the hydrogen clock not only keep the good short-term stability but also show much better long-term stability which achieves or surpasses that of HP5071A caesium clock, a caesium clock with middle-upper level. Thus the contribution of hydrogen clock to the time scale kept in time laboratories can be enhanced if the method discussed in this paper is adopted. 

Key words: hydrogen clock; frequency drift; time-keeping