Determination of the Critical Diameter of Explosive Materials

Abstract

A simple method of determining the critical diameter of cast and extruded charges is described; it consists of following the ionized detonation front, propagated from the base of a right circular cone, by means of an internal continuous wire sensor. The critical diameter is tha t cone diameter at which detonation fails, i.e., ionization disappears. The method developed is found to be particularly appropriate for organic materials of moderate to low shock sensitivity. Measurements obtained during the development work ranged from 0.61 cm for octol 65/35 to 2.69 cm for creamed cast TNT; the individual record readings could be repeated to =h 0.03 cm and =b 0.2 cm, respectively, in critical diameter.