Pitfall in etch-pit calculation

Two widely used methods for computing the reduced etch rate from the etch-pit geometry in nuclear track detectors (NTDs) have been compared. The shape of the etch-pit is usually assumed to be conical. In this paper, the validity of that assumption has been tested and the applicability of these two methods in different regimes of specific energy loss have been investigated. Poly-ethylene terephthalate (PET) films were irradiated with 3.8 MeV/A$~^{35}$Cl beam from Inter-University Accelerator Center (IUAC), New Delhi, India for the purpose of our study. An updated calibration curve for PET has also been presented.