Diffusion of Solar Wind Noble Gases from Genesis Aluminum Collectors

The Genesis mission collected samples of solar wind (SW) over a two-year period and returned them to earth for high-precision laboratory measurements [1]. The exact temperatures that the collectors reached during exposure to the SW is unknown, however preflight simulations [2] and comparison of measurements from different target materials point to the potential for measurable losses due to thermally activated diffusion. We have conducted a diffusion experiment on a similar time scale as the Genesis mission to determine the diffusion parameters of the aluminum collector materials and to quantify the changes in the measured ratios due to diffusive losses. In this work we have studied the light noble gases: helium, neon, and argon.