The Kapitza thermal resistance between 3He or mixtures and sintered silver powders is a particularly important parameter for the design of low temperature heat exchangers.

Curves correspond to the Kapitza resistance measured between sintered silver powder heat exchangers and mixtures, either indirectly through the performance of heat exchangers (G. Frossati), or directly in cells containing helium mixture (H. Godfrin). Also shown are data between silver powders and pure 3He. A good agreement was obtained between measurements by Ahonen, Lounasmaa and Veuro (1978) and those obtained by H. Godfrin, shown in the graph. Source: H. Godfrin, PhD Thesis, 1981. Note: in the graph, “mél” stands for mixtures (mélange in French).

The following articles provide information on sintered silver powders and their application to heat exchangers

• Effect of boundary condition on Kapitza resistance between superfluid 3He-B and sintered metal, S. Autti, A. M. Guénault, A. Jennings, R. P. Haley, G. R. Pickett, R. Schanen, V. Tsepelin, J. Vonka, D. E. Zmeev, and A. A. Soldatov, Phys. Rev. B 102, 064508 (2020) https://doi.org/10.1103/PhysRevB.102.064508, ArXiv: https://arxiv.org/abs/2005.05838

• Thermal boundary resistance between liquid helium and silver sinter at low temperatures, A. Voncken, D. Riese, L. Roobol, R. König, F. Pobell, J. of Low Temp. Phys. 105, pages 93–112 (1996), https://doi.org/10.1007/BF00754629

• A Geometry dependent thermal resistance between a saturated dilute 3He - 4He Solution and sintered silver powder, D.J. Cousins, A.M. Guénault, G.R. Pickett, P. Thibault, R.P. Turner, E.N. Smith, C. Bäuerle, Yu.M. Bunkov, S.N. Fisher, H. Godfrin, J. of Low temp. Phys. 101, 259 (1995), https://doi.org/10.1007/BF00754586

• T−3 Temperature Dependence and a Length Scale for the Thermal Boundary Resistance between a Saturated Dilute He3-He4 Solution and Sintered Silver, Cousins, D. & Fisher, S. & Guénault, Anthony & Pickett, George & Smith, E. & Turner, R. Phys. Rev. Lett. 73, 2583-2586 (1994), https://doi.org/10.1103/PhysRevLett.73.2583.

• New silver powders with large surface area as heat exchanger materials (C8-powder), W.Itoh, A.Sawada, A.Shinozaki, Y. Inada, Cryogenics, 31, 453 (1991), https://doi.org/10.1016/0011-2275(91)90207-D

• A recipe for sintering submicron silver powders, V. Keith and M.G. Ward, Cryogenics, 24, 249 (1984), https://doi.org/10.1016/0011-2275(84)90151-6

• Properties of sintered silver powders and their application in heat exchangers at millikelvin temperatures, H. Franco, J. Bossy, H. Godfrin, Cryogenics, 24, 477 (1084) https://doi.org/10.1016/0011-2275(84)90006-7

• Properties of sintered-silver heat exchangers, P.A. Busch, S.P. Cheston, D.S. Greywall, Cryogenics, 24, 445 (1984) https://doi.org/10.1016/0011-2275(84)90021-3,https://ur.booksc.eu/book/2080630/728d06

• Properties of sintered submicron copper and silver powders and their relation to low temperature heat exchangers, R. J. Robertson, F. Guillon, J. P. Harrison, Can. J. of Phys. 61, (1983), https://doi.org/10.1139/P83-023