New calibrations and time stability of the response of the INTERCAST CR-39

We present new calibrations of different production batches (from 1989 to 1 999) of the INTERCAST CR-39, using the BNL-AGS 1 A GeV iron beam. The compa rison with previous results, obtained with the 158 A GeV lead beam from the CERN-SPS shows that, while each production batch has a different calibrati on curve (mainly due to minor differences in the production conditions), th e aging effect is negligible. We also tested the dependence of the CR-39 re sponse from the time elapsed between exposure and analysis (fading effect). The fading effect, if present, is less then 10%. It may be compatible with the experimental uncertainties on the bulk etching rate upsilon (B). (C) 2 001 Elsevier Science Ltd. All rights reserved.