WANG Jing-bin1,2, CHEN Jie1,2, WANG Xin-liang1,3, CHANG Hong1,3

(1. National Time Service Center, Chinese Academy of Sciences, Xi′an 710600, China;

2. Graduate University of Chinese Academy of Sciences, Beijing 100039, China;

3. Key Laboratory of Time and Frequency Primary Standards, National Time Service Center,

Chinese Academy of Sciences, Xi′an 710600, China)

Abstract: Owing to the different requirements to the magnetic field of magnetic-optical trap for the two different stages of cooling of Sr optical lattice clock, the magnetic field conversion needs to be controlled with a certain sequence within a short time for reducing the fleeing of the atoms in the magnetic field conversion. The theory of the anti-Helmholtz coil is discussed, a design of the magnetic field for the two-stage-cooling of Sr optical lattice clock is presented, and an occurring and controlling device for the magnetic conversion, which mainly contains control circuit and protection circuit, is manufactured. The measurement shows that the current through the coil is controlled by the input signal, meeting the experimental requirements.

Key words: Sr optical lattice clock; magnetic-optical trap; control of magnetic field