Rubidium frequency standard with pulsed optical pumping and frequency instability of 2.5 × 10−13τ − 1/2

The work is dedicated to the further development of a compact quantum frequency standard based on a rubidium gas cell with a mixture of buffer gases. The results of frequency measurements and analysis of short-term frequency instability obtained on a laboratory prototype of a microwave rubidium atomic frequency standard (RAFS) with pulsed optical pumping (POP) are presented. The main in magnitude contributions to the overall frequency instability of the RAFS with POP are estimated. Short-term frequency instability expressed in terms of the Allan deviation and measured at averaging times τ up to several tens of seconds, σy (τ) = 2.5×10−13 τ −1/2, coincides satisfactorily with the calculated value of σy (τ) = 2.1×10−13 τ −1/2.