Determination of the lifetime of the5 P122level ofRb85through the measurement ofn(2)(T)

In this paper we present the values we obtained for the lifetime of the $5 {}_{}{}^2{}_{}{}^{}P_{\frac{1}{2}}^{}{}_{}{}^{}$ level of ${}_{}{}^{85}{}_{}{}^{}\mathrm{Rb}$ using the Hanle effect. These measurements were carried out using two different methods: through a multichannel signal analyzer by photon counting and through a new method based on the determination of the normalized second-order factorial moment $n^{\mathrm{}\left(2\right)\mathrm{}}\mathrm{}\left(T\right)\mathrm{}$ of the fluorescence obtained. We discuss the results and advantages of the new method.