An analysis of major frequency shifts in the LPTF optically pumped primary frequency standard

An analysis of the major frequency shifts of the optically pumped cesium beam primary frequency standard of the Laboratoire Primaire du Temps et des Frequences (LPTF) is presented, together with a description of the most relevant characteristics of the device. The short-term frequency stability was measured against a hydrogen maser. The square root of the Allan variance /spl sigma//sub y/(/spl tau/) is, at present, 5.8 /spl times/ 10/sup -13/ /spl tau//sup -1/2/, with a flicker level at 3.3 /spl times/ 10//sup -15/. This extremely good frequency stability enables a highly precise analysis of the most important systematic frequency shifts to be performed in a short time. A first accuracy evaluation resulted in an uncertainty (1/spl sigma/) of 1.1 /spl times/ 10/sup -13/.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>