Prospects in improvement of accuracy performances of passive atomic frequency standards

Results are presented concerning experimental and theoretical investigations aimed at the improvement of accuracy characteristics of passive atomic frequency standards. A brief review is given of the parametric frequency shifts of the clock atomic transition in a cesium atomic beam tube and those of a rubidium gas cell atomic discriminator. The transformation of fluctuations in an atomic beam tube and in a passive atomic frequency standard is considered. The limit accuracy characteristics of passive frequency standards are given. These are derived on the basis of a multiparametric optimization of the atomic beam tube and atomic gas cell discriminator, as well as a complex optimization of the whole standard