On dewetting dynamics of solid films of hydrogen isotopes and its influence on tritium beta spectroscopy

The dewetting dynamics of solid films of hydrogen isotopes, quench-condense d on a graphite substrate, was measured at various temperatures below desor ption by observing the stray light from the film. A schematic model describ ing the dewetting process by surface diffusion is presented, which agrees q ualitatively with our data. The activation energies of different hydrogen i sotopes for surface diffusion were determined. The time constant for dewett ing of a quench-condensed T-2 film at the working temperature of 1.86 K of the mainz neutrino mass experiment was extrapolated.