Progress of the fountain frequency standard at NMIJ in 2008

National Metrology Institute of Japan (NMIJ) is developing two fountain frequency standards (NMIJ-F1, NMIJ-F2). NMIJ-F1 is in the phase of operation for continuous monthly report since February in 2008. The possibility of the reduction in the uncertainty caused by the collisional shift that mainly limits the total uncertainty of NMIJ-F1 is presented. The construction of NMIJ-F2 proceeded, and then the launched atomic signal was observed.