Figure 2

The ⁸⁵Rb polarization of ³⁹K (¹³³Cs)-⁸⁵Rb-⁴He magnetometers varies with the number density of the buffer gas (⁴He), the pumping rate of pump beam, number density of the quench gas N₂ and the cell temperature respectively. (a) ⁸⁵Rb polarization almost does not vary with the increasing ⁴He number density when ⁴He number density is smaller than a critical value about 10²⁰ cm ⁻³ in ³⁹K -⁸⁵Rb-⁴He (black line in squares) and ¹³³Cs-⁸⁵Rb-⁴He (red line in dots) magnetometers, otherwise, ⁸⁵Rb polarization decreases rapidly. (b) ⁸⁵Rb polarization almost does not vary with increasing N₂ number density when N₂ number density is smaller than about 2 × 10¹⁹ cm ⁻³ in ³⁹K-⁸⁵Rb-⁴He and ¹³³Cs-⁸⁵Rb-⁴He magnetometers, otherwise, the ⁸⁵Rb polarization decreases rapidly. (c) ⁸⁵Rb polarization increases with increasing \({R}_{p}^{K}\) and \({R}_{p}^{Cs}\) respectively. (d) ⁸⁵Rb polarization decreases with the increasing cell temperature. The ⁸⁵Rb polarization of ¹³³Cs-⁸⁵Rb-⁴He magnetometer is bigger than the one of ³⁹K-⁸⁵Rb-⁴He magnetometer in (a)–(d).