Abstract
We used Sub-Doppler laser cooling technique to cool down the 39K atoms lower than 200μK. In order to increase the life time of the ultra-cold atoms, then we magnetic caught and magnetic transferred the atoms by a moving anti-Helmholtz coil mounted on a linear motor track to the ultra-high vacuum chamber(Science cell). The number of atoms and the lifetime of trap were measured and analyzed using the fluorescence image method. In this experiment,1.21×10E8 of cold potassium atoms was produced in the MOT, and about 10% of that was loaded into the magnetic trap. The subsequent magnetic transferring to the science cell was achieved with a linear moving track and an efficiency of 24%. In the first chamber(MOT chamber), the life time of 39K was 2.55 sec. After transporting to Science cell, the life time increased to 14 sec due to less background collision. Meanwhile, we also trapped and transferred 87Rb and 39K simultaneously to the science cell. Because of the additional loss caused by the inter-species collision, the life time of 39K was reduced to 4sec.