Three kinds of firebricks infiltrated with litium hydroxide or carbonate were irradiated with neutrons and the liberation of tritium on heating the firebricks was investigated by using gas and liquid scintillation technique. Tritium produced by6Li (n, a) 3Hreaction was almost quantitatively recovered as tritiated water; the recovery was found to depend on porosity of firebricks. The liberation curves of tritium from the firebricks were more complicated than those from lithium hydroxide and carbonate.
It was found that p-nitrophenylacetylene polymerizes in chlorinated hydrocarbons by γ-ray irradiation, while it does not polymerize in the solid state, nor in the oxygen-containing organic solvents. The rate of polymerization in methylene chloride at 25°C was approximately proportional to the intensity of γ-ray, and the value of the apparent activation energy for the polymerization was negative. These results can be explained on the assumption that the polymerization in the chlorinated hydrocarbons is initiated by cationic species. The results obtained from the mass spectrometry of the monomer are consistent with the above assumption. The molecular weight distribution, the d.c. conductivity, and the UV-visible spectra of the polymers were measured.