Preliminary evaluation of the Cs atomic fountain frequency standard at NMIJ/AIST

With the aim of contributing to the calibration of the International Atomic Time Scale (TAI), a cesium atomic fountain frequency standard is developed at the National Metrology Institute of Japan. The short-term stability is measured to be (sigma)((tau))=4.7*10/sup -13/*(tau)/sup -1/2/ by comparison with a hydrogen maser. Preliminary results of the accuracy evaluation, including measurement of the second-order Zeeman shift, are presented.