Crossover analyses of heat capacity and susceptibility measurements near the 3He liquid-gas critical point

An experiment called MISTE (Microgravity Scaling Theory Experiment) is being developed for a future mission on the International Space Station. The main objective of this flight experiment is to perform in-situ PVT, heat capacity at constant volume, C-V, and isothermal susceptibility, chi (T), measurements in the asymptotic region of the He-3 liquid-gas critical point. On the ground, gravity induces a density gradient that does not permit an accurate test of theoretical predictions within the asymptotic region. In preparation for this flight experiment, precision ground-based measurements are now being performed in the crossover region away from the critical point to determine the crossover parameters. Recent C-V and chi (T) measurements along the critical isochore have been analyzed using a new crossover parametric equation-of-state and a field theoretical Renormalization Group calculation based upon the phi (4) model. A description of the experimental techniques and preliminary results of the theoretical analyses will be presented.