Source Mass Development for the Axion Resonant InterAction DetectioN Experiment (ARIADNE)

The axion, a light pseudoscalar particle postulated as a solution to the strong CP problem of quantum chromodynamics, has emerged as a leading dark matter candidate.  It is also predicted to mediate weak forces between fermions.  The Axion Resonant InterAction DetectioN Experiment (ARIADNE) uses Nuclear Magnetic Resonance techniques to probe axion-mediated forces between nucleons with unprecedented sensitivity.  A dense, non-magnetic, rotating sprocket is brought into close proximity with a cell of polarized ³He atoms, which are in turn monitored for an induced transverse magnetization with a SQUID sensor.  Matching the source rotation to the frequency of the ³He precession is critical to reaching the desired sensitivity.  This poster describes the techniques used to develop the source mass, including a periodic, reflective pattern on it for tracking the angular velocity with a laser.  Thin film deposition is used to create metallic patterns on a silicon wafer, which is then attached to the sprocket.  This process has demonstrated good pattern adhesion and conductivity.  The projected sensitivity of the experiment is also discussed.