Jason M. Amini

An electrostatic lens with three focusing elements in an alternating-gradient configuration is used to focus a fountain of cesium atoms in their ground (strong-field-seeking) state. The lens electrodes are shaped to produce only sextupole plus dipole equipotentials which avoids adding the unnecessary nonlinear forces present in cylindrical lenses. Defocusing between lenses is greatly reduced by having all of the main electric fields point in the same direction and be of nearly equal magnitude. The addition of the third lens gave us better control of the focusing strength in the two transverse planes and allowed focusing of the beam to half the image size in both planes. The beam envelope was calculated for lens voltages selected to produced specific focusing properties. The calculations, starting from first principles, were compared with measured beam sizes and found to be in good agreement. Application to fountain experiments, atomic clocks, and focusing polar molecules in strong-field-seeking states is discussed.

A Cs fountain electron electric dipole moment (EDM) experiment using electric-field quantization is demonstrated. With magnetic fields reduced to 200 pT or less, the electric field lifts the degeneracy between hyperfine levels of different|mF| and, along with the slow beam and fountain geometry, suppresses systematics from motional magnetic fields. Transitions are induced and the atoms polarized and analyzed in field-free regions. The feasibility of reaching a sensitivity to an electron EDM of 2 x 10 exp(-50) C-m [1.3 x 10 exp(-29) e-cm] in a cesium fountain experiment is discussed.

The cesium 6S_1/2 scalar dipole polarizability alpha_0 has been determined from the time-of-flight of laser cooled and launched cesium atoms traveling through an electric field. We find alpha_0 = 6.611+-0.009 x 10^-39 C m^2/V= 59.42+-0.08 x 10^-24 cm^3 = 401.0+-0.6 a_0^3. The 0.14% uncertainty is a factor of fourteen improvement over the previous measurement. Values for the 6P_1/2 and 6P_3/2 lifetimes and the 6S_1/2 cesium-cesium dispersion coefficient C_6 are determined from alpha_0 using the procedure of Derevianko and Porsev [Phys. Rev. A 65, 053403 (2002)].

A method of slowing, accelerating, cooling, and bunching molecules and neutral atoms using time-varying electric-field gradients is demonstrated with cesium atoms in a fountain. The effects are measured and found to be in agreement with our calculations. Time-varying electric-field-gradient slowing and cooling is applicable to atoms that have large dipole polarizabilities, including atoms that are not amenable to laser slowing and cooling, to Rydberg atoms, and to molecules, especially polar molecules with large electric dipole moments. The possible applications of this method include slowing and cooling thermal beams of atoms and molecules, launching cold atoms from a trap into a fountain, and measuring atomic dipole polarizabilities.

A method of slowing, accelerating, cooling, and bunching molecules and neutral atoms using time-varying electric field gradients is demonstrated with cesium atoms in a fountain. The effects are measured and found to be in agreement with calculation. Time-varying electric field gradient slowing and cooling is applicable to atoms that have large dipole polarizabilities, including atoms that are not amenable to laser slowing and cooling, to Rydberg atoms, and to molecules, especially polar molecules with large electric dipole moments. The possible applications of this method include slowing and cooling thermal beams of atoms and molecules, launching cold atoms from a trap into a fountain, and measuring atomic dipole polarizabilities.