Design of a non-magnetic temperature control system using AC bridge to measure temperature

As the latest type of magnetometer, the SERF (spin exchange relaxation free) atomic spin magnetometer has ultrahigh theoretical accuracy. The alkali vapor cell, as the sensitive meter of the atomic spin magnetometer that carries the atomic spin ensemble, should minimize the magnetic field interference introduced by the alkali vapor cell temperature control system during the entire temperature measurement and heating process. Therefore, the realization of a non-magnetic temperature control system is very important to the SERF atomic spin magnetometer. At present, most alkali vapor cell temperature control systems use platinum resistance temperature measurement and electric heating schemes. The platinum resistance and heating film are the closest sources of low-frequency magnetic field interference to the alkali vapor cell. Therefore, this paper designs a scheme that uses AC bridge temperature measurement and high-frequency sine wave heating, which modulates the interference in the temperature measurement and heating process from low-frequency to high-frequency, avoids low-frequency magnetic field noise, and provides a good non-magnetic environment for the SERF atomic spin magnetometer. At the same time, experiments show that the non-magnetic temperature control system has good accuracy and stability.