Measurement of the blackbody shift in the IEN Cs fountain

Abstract

This paper reports a review of the blackbody radiation (BBR) shift theory for the Cs atom hyperfine clock transition, together with a measurement of the blackbody radiation shift in an atomic cesium fountain. In the first part a derivation of the BBR theory from the AC Stark shift theory is reported, together with a numerical evaluation of BBR shift parameters for the Cs clock transition. The second part presents a measurements of the BBR shift for the Cs clock transition in the IEN Cs fountain (IEN-CsFl). The measurement is performed operating the fountain at different temperatures. Results are then discussed and compared with those obtained with different techniques.