Summary: "The quantity of water adsorbed by graphite at various relative pressures has been determined and the data are presented in graphical and tabular form."

The construction and operation of a fission gas generator, containing about 25 grams of uranium in the form of a powder with a high specific surface, are described in detail. The purpose of the work discussed in this report was to examine the feasibility of producing, separating, and assaying samples of Xe135 in preparation for a proposed measurement of the neutron cross section of this isotope. Krypton and xenon are separated by selective adsorption on charcoal at reduced temperature while iodine is removed by charcoal sorption at room temperature.

The effects of oxidation and irradiation on the microsurface structure of pile graphite have been investigated by measuring the surface area and pore size distribution of several samples. The results obtained for both oxidized and irradiated graphite samples indicate that changes in surface characteristics which occur are determined by the flux, temperature of irradiation, and gaseous atmosphere in which the radiation takes place.

Ionization measurements of water vapor in vapor-liquid equilibrium were made with a series of chambers on a tritiated water sample which was prepared by burning T2 to T2O and diluting it with H2O. A correction was made for the difference of vapor pressures of HTO and H2O. The effect of HTO adsorbed on chamber walls and electrodes was eliminated from the final result. Using Gerbes data on the number of electron volts to produce an ion pair in air, agreement obtained between the measured source strength and the source strength as computed from pressure, temperature, volume, purity, and dilution data on the original gaseous T2 sample.