Title :
Accuracy evaluation of the optically pumped Cs frequency standard at NRLM
Author :
Hagimoto, Ken ; Ohshima, S. ; Nakadan, Y. ; Koga, Yasuki
Author_Institution :
Nat. Res. Lab. of Metrol., Ibaraki, Japan
fDate :
4/1/1999 12:00:00 AM
Abstract :
The optically pumped cesium (Cs) frequency standard at the National Research Laboratory of Metrology, Ibaraki, Japan (NRLM), NRLM-4, was modified in various ways in order to improve frequency stability and accuracy, We determined the frequency stability by comparing the phase with that of a hydrogen maser: the Allan deviation was σy(τ)=5×10-13/√τ. We estimated the frequency corrections and uncertainties due to various sources, and the total uncertainty was found to be 2.9×10-14 . The frequency difference between NRLM-4 and the international atomic time (TAI) was also measured
Keywords :
atomic clocks; frequency stability; frequency standards; measurement uncertainty; Allan deviation; Cs; NRLM-4; National Research Laboratory of Metrology; frequency corrections; frequency stability; international atomic time; optically pumped frequency standard; total uncertainty; Atomic measurements; Frequency estimation; Frequency measurement; Hydrogen; Laboratories; Masers; Metrology; Optical pumping; Stability; Time measurement;
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on
