Several Borosilicate glass tubes in which Ne gas had been sealed were maintained at either room or liquid nitrogen temperature for a long period, i.e., 10-70 days. Thermal desorption measurements were carried out using a quadrupole mass spectrometer to determine the amount of Ne atoms absorbed in the tube walls during gas sealing. In the case of samples kept at room temperature, with prolongation of the gas sealing period, desorption peaks shifted to higher temperature and the total amount of

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... sorbed Ne increased, as expected from diffusion theory. In the case of samples kept at liquid nitrogen temperature, however, their thermal desorption behavior was markedly different; although the amount of desorption was much smaller than that for the room-temperature samples, the desorption-peak temperature was apparently unaffected by the sealing period. This indicates that most of the penetrating Ne atoms were trapped within a certain limited range of depth from the Ne-exposed glass surface. The results support the view that atoms with extremely low energy (on the order of meV) can move within a solid over a considerable distance (on an atomic scale) , unlike in ordinary thermal diffusion.