Magnetic Field Suppression System for the Measurement of the Cs Ground State Tensor Polarizability

An improved Cs Ground State Tensor Polarizability (GSTP) measurement will provide a test for atomic theory used in atomic parity non-conservation measurements. The GSTP measurement is sensitive to background magnetic field fluctuations on the order of a few mG, despite a magnetic shield surrounding the Cs atoms. These background magnetic fields can fluctuate at a rate of 5 mG over a few minutes, a rate much faster than the current apparatus can correct for. To quickly suppress background magnetic fields, we are building a feed-forward system that monitors the B-field change using a magnetometer and cancels it by slightly changing the current flowing in a set of large Helmholtz coils that surrounds the apparatus. The efficacy of the suppression system at the point of the experiment will finally be determined using the trapped atoms, with an expected suppression of field fluctuation by a factor of ten.