AC Magnetic Guide for Cold Atoms in an Ioffe Tube
We propose a novel ac magnetic waveguide for cold neutral atoms in an Ioffe tube. The time-averaged magnetic potential and force for the guided atoms in the magnetic guiding tube are calculated, and the results show that it is high enough to collect and guide nearly all of cold atoms from a standard magneto-optical trap with a temperature of ~120μK. We also estimate the atomic losses from background thermal-atom collision, quantum tunneling effect and spin-flip transition in the guiding. Our study shows that a cold and dense atomic beam with a guiding efficiency of ~92% and a beam intensity of about 1011 atoms/cm 2• s can be output from the magnetic guide tube, and the guiding scheme proposed here could be used to manipulate spin polarized cold atoms.
It is shown that the temperature gradients caused by the heating of an angularly accelerated gas due to compression and the converse cooling of the decelerated gas have appreciable effects on isotope separation factors as determined by centrifugation. These effects were found to be greater than would be indicated by the isothermal theory. The influence of these non-uniform temperatures on the performance of flow-through centrifuges is discussed. (C.J.G.)