Performance comparison between $$^{87}$$ 87 Rb-natural Xe– $$\hbox {N}_2$$ N 2 and $$^{87}$$ 87 Rb– $$^{129}$$ 129 Xe– $$^{131}$$ 131 Xe– $$\hbox {N}_2$$ N 2 atom spin gyroscopes

We have developed an atom spin gyroscope that uses a Rb–Xe vapor cell. The signal-to-noise ratio (SNR) and the angular random walk (ARW) of a Rb-natural Xe– $$\hbox {N}_2$$ vapor cell and a Rb– $$^{129}$$ Xe– $$^{131}$$ Xe– $$\hbox {N}_2$$ vapor cell were compared in terms of the Allan deviation. The low SNR of the $$^{131}$$ Xe signal was the main limitation of the ARW in the $$^{87}$$ Rb-natural Xe– $$\hbox {N}_2$$ atom spin gyroscope. The $$^{87}$$ Rb– $$^{129}$$ Xe– $$^{131}$$ Xe– $$\hbox {N}_2$$ atom spin gyroscope with a partial pressure ratio of $$^{129}$$ Xe to $$^{131}$$ Xe of 1:5 provided a SNR of 879 and a transverse relaxation time of 19.6 s, respectively, for an $$^{131}$$ Xe signal. Compared to the $$^{87}$$ Rb-natural Xe– $$\hbox {N}_2$$ atom spin gyroscope, the $$^{87}$$ Rb– $$^{129}$$ Xe– $$^{131}$$ Xe– $$\hbox {N}_2$$ atom spin gyroscope with an improved SNR showed that the magnetic-field-induced noise limited the ARW of our system. To stabilize the bias magnetic field, we applied a magnetic field feedback of 300-fT resolution with a 4-Hz bandwidth. As a result, the correlation between the magnetic field and the rotation rate from the atom spin gyroscope output was removed. The $$^{87}$$ Rb– $$^{129}$$ Xe– $$^{131}$$ Xe– $$\hbox {N}_2$$ atom spin gyroscope achieved an ARW of $$0.11^\circ /$$ $${\mathrm {h}}^{1/2}$$ and a bias instability of $$0.5 ^\circ {/}$$ h.