New classes of systematic effects in gas spin co-magnetometers

Atomic co-magnetometers are widely used in precision measurements searching for spin interactions beyond the Standard Model. We describe a new $^3$He-$^{129}$Xe co-magnetometer probed by Rb atoms and use it to identify two general classes of systematic effects in gas co-magnetometers, one associated with diffusion in second-order magnetic field gradients and another due to temperature gradients. We also develop a general and practical approach for calculating spin relaxation and frequency shifts due to arbitrary magnetic field gradients and confirm it experimentally.Comment: 5 pages, 4 figure

Studies of emittance growth and halo particle production in intense charged particle beams using the Paul Trap Simulator Experiment

The Paul Trap Simulator Experiment (PTSX) is a compact laboratory experiment that places the physicist in the frame-of-reference of a long, charged-particle bunch coasting through a kilometers-long magnetic alternating-gradient (AG) transport system. The transverse dynamics of particles in both systems are described by the same set of equations, including nonlinear space-charge effects. The time-dependent voltages applied to the PTSX quadrupole electrodes in the laboratory frame are equivalent to the spatially periodic magnetic fields applied in the AG system. The transverse emittance of the charge bunch, which is a measure of the area in the transverse phase space that the beam distribution occupies, is an important metric of beam quality. Maintaining low emittance is an important goal when defining AG system tolerances and when designing AG systems to perform beam manipulations such as transverse beam compression. Results are reviewed from experiments in which white noise and colored noise of various amplitudes and durations have been applied to the PTSX electrodes. This noise is observed to drive continuous emittance growth and increase in root-mean-square beam radius over hundreds of lattice periods. Additional results are reviewed from experiments that determine the conditions necessary to adiabatically reduce the charge bunch's transverse size and simultaneously maintain high beam quality. During adiabatic transitions, there is no change in the transverse emittance. The transverse compression can be achieved either by a gradual change in the PTSX voltage waveform amplitude or frequency. Results are presented from experiments in which low emittance is achieved by using focusing-off-defocusing-off waveforms. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3354109close4

RF Depolarization of Potassium in a 3He-129Xe Comagnetometer

Noble gas comagnetometers have applications to searches for spin-gravity couplings, electric dipole moments, and nuclear spin gyroscopes, but their sensitivity is still very far from fundamental limits. The previously demonstrated 3He-129Xe comagnetometer probed by an alkali metal magnetometer has both the long coherence of a noble gas and the sensitivity of an alkali metal, allowing near-quantum limited detection of nuclear spins. However, the collisions between the polarized metal and the noble gas lead to a shift in the nuclear precession frequency. Here, we show that the application of RF radiation at the hyperfine transition in potassium can achieve greater than 99.7% depolarization of the alkali metal. We also demonstrate power broadening of the Zeeman levels, and explore the limitations of this technique