Dynamic and gravitational effects on the correlation volume: Experimental methods

We report on the design of a new prototype flight instrument that will be used to repeat previous Earth-based measurements of nonlinear heat transport near the superfluid transition in the microgravity laboratory. Since this nonlinear conductivity is associated with dynamic limitations to the divergent correlation length, and since gravitational acceleration also limits the correlation length's divergence, we anticipate that the nonlinear conductivity will depend strongly on gravitational acceleration. The apparatus, data taking procedure, systematic corrections, and error sources are discussed here.