Bulk and track etch properties of CR-39 SSNTD etched in NaOH/ethanol

Recently, Matiullah et al. described the use of NaOH/ethanol as an etchant for the CR-39 detector, and have determined the corresponding bulk and track etch properties from the track diameter method. In the present work, the bulk and track etch properties of CR39 in NaOH/ethanol were derived from direct measurements. The bulk etch rate has been found to increase with the molarity of NaOH/ ethanol, reach a maximum at 2.5 N and start to drop beyond 3 N. The bulk etch rate also increases with stirring. These phenomena can be explained by the insulation of the detector from the etchant by the etched products. Regarding the track etch, we have found a surprising result that the lengths of (pre-etched) tracks are actually shortened when the tracks are etched in NaOH/ethanol. Generally speaking, the remaining track depths obtained with stirring are longer than those for no stirring. The shortening of the tracks can be explained by the insulation of the pre-etched track wall from the etchant with the etched products. 2007 Elsevier B.V. All rights reserved.