Sympathetic cooling of a large 113Cd+ion crystal with 40Ca+in a linear Paul trap

We have sympathetically cooled and crystallized 113Cd+ ions with laser-cooled 40Ca+ ions, and directly observed the complete large bicrystal structure in a linear Paul trap. The large two -component crystal contains up to 3.5x103 40Ca+ ions and 6.8x103 113Cd+ ions. The temperature of the crystallized 113Cd+ ions was measured to be as low as 41 mK with a large mass ratio, which is twice as low as that of our previous work. Based on the bicrystal obtained in previous work, we have further studied several properties and structures of the ultracold sample. The factors affecting the sympathetic cooling effect were studied, including the electrical parameters and the number ratio between laser-cooled ions and sympathetically-cooled ions. The results of this paper enrich the experimental research of large two-component ion crystals, and the ultracold sample of 113Cd+ ions makes it possible to further improve the accuracy of the cadmium-ion microwave frequency standard.

Automated summary

By sympathetically cooling and crystallizing 113Cd+ ions with laser-cooled 40Ca+ ions, we have observed the complete large bicrystal structure in a linear Paul trap directly. The bicrystal consists of up to 3.5x103 40Ca+ ions and 6.8x103 113Cd+ ions. The temperature of the crystallized 113Cd+ ions was measured to be as low as 41 mK with a large mass ratio, which is twice as low as our previous work. We have further studied various properties and structures of the ultracold sample based on the bicrystal obtained in previous work. Factors affecting the sympathetic cooling effect, such as electrical parameters and the number ratio between laser-cooled ions and sympathetically-cooled ions, were investigated. The results of this paper enrich the experimental research of large two-component ion crystals, and the ultracold sample of 113Cd+ ions enables further improvement in the accuracy of the cadmium-ion microwave frequency standard.