STRESS-INDUCED ANISOTROPIC ETCHING IN POLYMER TRACK DETECTORS

CR-39 track detectors irradiated with alpha particles were chemically etched while under mechanical stress. Depending on tensile stress magn itude the response of track size and shape was observed to form two di stinct domains: in the first domain sizes of track minor and major axi s both increase slightly with increasing stress while in the second do main tracks show new shape due to a triangular extensions perpendicula r to the stress direction. A simple model is proposed which explains t he new etched track shape. With increasing compressive stress both min or and major axis sizes decrease but no change in shape occurs.