An attempt is made to determine the response of CR-39 and cellulose nitrate plastic track detectors subjected to thermal neutrons. The α-particles are produced from (n, α) reactions in lithium tetraborate convertor placed in contact with different plastics and are recorded in the detectors. The corrected track density gives a fluence sensitivity and dose sensitivity of the order of 10⁻⁴ tracks per neutron and 10² tracks/cm² mrem respectively. A linear relationship is observed between track density and neutron fluence.

Makrofol polycarbonate plastic track detectors have been exposed to₅₄¹³²Xe -ions of energy 1.1 MeV/N from the cyclotron beam. The bulk etch rate and track etch rate are measured for different temperatures and the activation energies are calculated. The maximum etched track length is compared with the theoretically computed range. The critical energy loss is (dE/dx)_c=5 MeV cm² mg⁻¹ for this detector material.

Measurements of the dependence of track etch rate on the energy-loss of different ions have been presented. In this method,₁₈⁴⁰Ar,₁₀²²Ne,₈¹⁶O and₆¹²C-ions of different energies are used as energetic heavy ions for track formation in the detectors. The bulk etch rate and track etch rate are measured for different temperatures and hence the activation energies are determined. The variation ofV =V_t/V_b along the trajectory of the track has been shown for different temperatures. The maximum etched track length is compared with the theoretical range as well as with the range reported earlier. The experimental results indicate the absence of a well-defined threshold in the plastics studied.

Samples of Lexan and Makrofol-E polycarbonate plastic track detectors were exposed to 1·1 MeV/N₅₄¹³²Xe-ions to investigate the thermal track fading properties of these plastics. The experimental results show that there is no effect of annealing on the bulk etch rate while the track etch rate decreases with annealing. The track diameter decreases with increase in annealing time and temperature. It is also observed that the track density is reduced as a result of annealing. The experiments reveal that the track lengths are, in general, decreased by the application of heat and that the oblique tracks are less stable than the vertical tracks. The decrease in diameter of₅₄¹³²Xe-ion tracks in Makrofol-E due to heat treatment is faster than that of₅₄¹³²Xe-ion tracks in Lexan.

The etch pit diameters of soda glass detector samples exposed to₅₄¹³²Xe-ions of different energies are measured for different etching times after etching the detector in a ‘new etchant’ free of the adverse effect of the etch product layer. The dependence of track diameter on the energy and on the energy loss, dE/dx of₅₄¹³²Xe-ion in soda glass has been presented. The energy resolution of soda glass and the critical angle for etching of fission fragment tracks in glass detectors have also been determined. The maximum etched track length of₅₄¹³²Xe-ion in soda glass has been compared with the theoretical range. The effects of different annealing conditions on bulk etch rate of glass detector and on diameters of₅₄¹³²Xe-ion tracks have been presented. Experimental results show that there is a decrease in track etch rate, etching efficiency and etchable range of₅₄¹³²Xe-ions with annealing. The annealing of oblique tracks shows that the vertical tracks are more stable than the oblique tracks.

The effect of heat treatment on the latent tracks in cellulose nitrate plastic track detectors has been studied. The bulk etch rate increases with annealing temperature while the track diameters of different ions in cellulose nitrate decrease with increase in annealing time and temperature. Experimental results show that for heavier ions higher temperatures are needed for their complete erasure. The track length and track etch rate are decreased by the application of heat. Experiments reveal that annealing reduces track density. The vertical tracks are more stable than the oblique tracks and require higher temperature for their complete erasure.

The track etch rates of₁₀²⁰Ne-ion in cellulose nitrate (LR-115) have been measured for different temperatures and the activation energy is determined. The experimental results show that both the track etch rate and the normalized track etch rate depend on the energy loss as well as on etching temperature. The maximum etched track length of₁₀²⁰Ne-ion agrees with the theoretically computed range. The experimental results show that there is no sharp threshold, at least in CN(LR-115).