THE EFFECT OF GAMMA-IRRADIATION ON THE DENSITY OF VARIOUS TYPES OF SILICA

The radiation-induced changes in density of 11 different silicas, both natural and synthetic, exposed to gamma-irradiation from 10(4)-10(9) rad were measured using a linear density gradient column. It was determined that, in general, the 'dry' silicas that contain less than 150 ppm OH compact monotonically with dose; however, the silicas containing more than 150 ppm OH tend to expand initially and then compact at higher doses.