A general saturation curve for an ionization chamber filled with nitrogen at pressures up to 8 atmospheres

A plane parallel ionization chamber, which was designed to permit high collecting fields to be applied to the layer of ionized gas without introducing local field concentrations which might tend to produce brush discharges, was used. By interchanging the insulating spacing rings, six different electrode spacings could be obtained, ranging from 3 to 13 mm. Irradiation was from a 2000 Ci 60Co source, the dose rate being varied by moving the chamber to different distances from the source.