Interpretation of the bulk etching process in LR-115 detectors by the many-hit model

The formalism of the many-hit model (MHM) [Fromm, M., Awad, E.M., Ditlov, V.A., 2004. Many-hit model calculation for track etch rate in CR-39 SSNTD using confocal microscope data. Nucl. Instr. Phys. Res. B 26, 565–575; Ditlov, V.A., Awad, E.M., Fromm, M., Hermsdorf, D., 2005. The Bragg-peak studies in CR-39 SSNTD on the basis of many-hit model for track etch rates. Radiat. Meas. 40, 249–254] is applied in order to describe the bulk etching rate VBVB of non-irradiated polymer detectors. In such a case the etching process should be easier to understand in terms of interactions of physical and chemical processes superimposing material diffusion and reaction kinetics. In a paper [Ditlov, V.A., 2005. Formation model of bulk etching rate for polymer detectors. Radiat. Meas. 40, 240–248] first attempts have been made to develop formulae for the calculation of VBVB dependence on the concentration C and temperature T   of the etchant solution. Therein, it is shown that VBVB have to be studied in a broad range of C and T   including very low and very high values. The formulae of the MHM contain some free adjustable parameters of definite physical meaning, which have to be determined by fitting the experimental data. In the present paper data for VBVB of LR-115 cellulose nitrate detectors have been analysed to decide on the reliability of the modelling of etching processes and to determine possible physical-based parameters.