LAUSR

We propose a method for the precise determination of nuclear spin polarization, based on the atomic magnetometers, which employs the effective magnetic field produced by the spin polarization of 129Xe nuclei. This effective magnetic field can be estimated by measuring the initial induced voltage of the Free Induction Decay (FID) signal of the 129Xe nuclei, which is based on the calibration coefficient between the transverse magnetic field and the output voltage signal of the atomic magnetometer, by using an off-resonant transverse driven magnetic field. Compared with the method based on measuring the longitudinal relaxation time of the 129Xe nuclei and the spin polarization of alkali-metal atoms, our method can directly measure the nuclear spin polarization, without being affected by inaccuracies in the measurement of the spin polarization of alkali-metal atoms.