Tracks in glasses from fission fragments with fixed parameters

Sodium silicate and phosphate glasses were irradiated on a mass seperator of fission fragments which enabled separation of fragments with strictly fixed parameters (E, M, Z_eff) and the change of only one parameter while the two others remained fixed. The following conclusions were drawn from the results of the measurements made: the diameter in the first two stages of etching is determined by the fragment's dE/dx, and in the third stage also by the length of the radiation damage zone; the main parameter of a fragment, influencing the track diameter, is its speed.

To explain the linear dependence of the track diameter on the etching time in sodium silicate glasses, an assumption is required concerning the three zones of track etching: the axial, the peripheral and the interstitial, where the etching rates are different.

Spectrometric characteristics of the glasses used have been determined, and it is shown that the studied phosphate glasses, in comparison with ZnP, have a greater dispersion of track diameters, which causes a lower energy resolution and the necessity of selecting optimum etching.