  The Axion Resonant InterAction Detection Experiment (ARIADNE) is a
collaborative effort to search for the QCD axion using nuclear magnetic
resonance (NMR), where the axion acts as a mediator of spin-dependent forces
between an unpolarized tungsten source mass and a sample of polarized helium-3
gas. Since the experiment involves precision measurement of a small
magnetization, it relies on limiting ordinary magnetic noise with
superconducting magnetic shielding. In addition to the shielding, proper
characterization of the noise level from other sources is crucial. We
investigate one such noise source in detail: the magnetic noise due to
impurities and Johnson noise in the tungsten source mass.
