Huang Zongjun

A picotesla atomic magnetometer operating at normal temperature

The basic principle of atomic magnetometer is to measure the precession frequency of polarized atomic spins in a magnetic field. The paper describes the optical pump, probe process and spin relaxation mechanisms. The magnetometer based on Cs atom is demonstrated in the experiment. At normal temperature 30°C the magnetometer achieves 8nT magnetic resonance widths and magnetic field sensitivity of 4.8pT/Hz1/2. It is more convenient for miniature structure design due to operate in lower temperature.

A research on the optimum parameters for multishell cylindrical magnetic shields

This paper gives a general theory of shielding efficiencies for magnetic shields including single-layer and multishell cylindrical ones. The differences of shielding efficiencies between multishell cylindrical shields with and without end-caps are also discussed. The optimum parameters (the innermost radius and length and radial and axial air gap) for five-shell cylindrical magnetic shields are expressed here after a detail theoretical analysis. While three of the four parameters are fixed, the optimum value of the last one is found. The residual magnetic field inside a set of three nested magnetic shields is measured experimentally, which is found to agree well with the theory.

A high stability magnetic field applied in atomic magnetometer system

A pair of Helmholtz coils producing a magnetic field with super-high stability in atomic magnetometer experiment has been designed and realized. To drive this coils, we developed a DC constant current source, which can provide a near 1 mA DC current with short-term stability of 5.8 parts in 107 in experimentally. Analysis shows that the stability of center magnetic field is about 0.06 pT.