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| Design of Magnetic Shield for Cesium Fountain Clock |
| LIU Kun, FANG Fang, CHEN Wei-liang, LIU Nian-feng, SUO Rui, LI Tian-chu |
| Division of Time & Frequency, National Institute of Metrology, Beijing 100013, China |
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Abstract The high quality magnetic shielding system is one of the most important components of cesium fountain clock.Firstly, the three parameters for magnetic shielding performance evaluation were defined, i.e.uniform range, the starting position of uniform range and shielding factor.And then, the results for different configurations of three layer cylindrical magnetic shield sets using finite element calculation are presented.In particular, effects on shielding of radial and axial spacing between shield layers, the length of sleeves weld on the end cap and the connection geometry between end caps and shield cylinders are examined.From the calculation results, the performance of optimal configuration of three layer shield sets is compared with the four layer ones used in NIM5 cesium fountain clock.This is important in design and assemble the magnetic shielding for the next generation cesium fountain clock to improve the accuracy.
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2014, Vol. 35 
