Permeation Eccentricities of He, Ne, and D‐T from Soda‐Lime Glass Microbubbles

Permeation of 3 He, Ne, and D‐T (deuterium‐tritium) was studied through batches of several million glass microbubbles. Although the calculated permeabilities agree roughly with literature data, the bubbles show several vagaries. Isothermal outgassing is not exponential but shows “tails” that become more pronounced at lower temperatures. An isotopic disproportionation effect occurs in the bubble loading at 698 K. Gas that has permeated the glass walls is more deuterium‐rich and the effect is increased by large amounts of 3 He in the feed gas. Finally, a slow and unexplained leakage occurs when loaded bubbles are stored for many months at 243 K. Data are also presented on bubble size distributions and mean wall thicknesses.