Neutron-Detected Tomography of Impurity-Seeded Superfluid Helium

We describe a neutron radiography technique that can be used to map the distribution of $^{3}\mathrm{H}\mathrm{e}$ impurities in liquid $^{4}\mathrm{H}\mathrm{e}$, providing direct and quantitative access to underlying transport processes. Images reflecting finite normal- and superfluid-component $^{4}\mathrm{H}\mathrm{e}$ velocity fields are presented.