Activation Energies For Bulk Etching Research Articles

Study of gamma irradiation effects on the etching and optical properties of CR-39 solid state nuclear track detector and its application to uranium assay in soil samples

The gamma irradiation effects in the dose range of 2.5–43.0 Mrad on the etching and optical characteristics of CR-39 solid state nuclear track detector (SSNTD) have been studied by using etching and UV–Visible spectroscopic techniques. From the measured bulk etch rates at different temperatures, the activation energies for bulk etching at different doses have also been determined. It is seen that the bulk etch rates increase and the activation energies for bulk etching decrease with the increase in gamma dose. The optical band gaps of the unirradiated and the gamma -irradiated detectors determined from the UV–Visible spectra were found to decrease with the increase in gamma dose. These results have been explained on the basis of scission of the detector due to gamma irradiation. The present studies can be used for the estimation of gamma dose in the range of 2.5–43.0 Mrad and can also be used for estimating track registration efficiency in the presence of gamma dose. The CR-39 detector has also been applied for the assay of uranium in some soil samples of Jammu city.

Estimation of track registration efficiency in solution medium and study of gamma irradiation effects on the bulk-etch rate and the activation energy for bulk etching of CR-39 (DOP) solid state nuclear track detector

The fission track registration efficiency of diethylene glycol bis allyl carbonate (dioctyl phthalate doped) [CR-39 (DOP)] solid state nuclear track detector (SSNTD) in solution medium (Kwet) has been experimentally determined and is found to be (9.7 ± 0.5) × 10−4 cm. This is in good agreement with the values of other SSNTDs. The gamma irradiation effects in the dose range of 50.0–220.0 kGy on the bulk etch rate, Vb and the activation energy for bulk etching, E of this solid state nuclear track detector (SSNTD) have also been studied. It is observed that the bulk etch rates increase and the activation energies for bulk etching decrease with the increase in gamma dose. These results have been explained on the basis of scission of the detector due to gamma irradiation.

The etching, optical and thermal response of a newly developed nuclear track detector called NADAC-ADC copolymer to gamma-irradiation

The bulk-etch rates of a newly developed track detector which is a copolymer of N-allyloxycarbonyl diethanolamine-bis allylcarbonate (NADAC) and allyl diglycol carbonate (ADC) [NADAC-ADC (1:1, w/w)] have been determined at different temperatures to deduce its activation energy. The energy of activation is found to be (0.93 ± 0.07) eV. This compares very well with the values of activation energy reported in the literature for the most commonly used nuclear track detectors. The effects of gamma irradiation on this new detector in the dose range of 47.0–145.0 kGy have also been studied using bulk etch, UV–visible spectroscopic, and thermogravimetric analysis (TGA) techniques. The activation energy for bulk etching calculated from bulk etch rates measurements at different temperatures, optical band gaps determined from the UV–visible spectra, and the values of onset temperature of decomposition (T0) calculated from TGA curves were found to decrease with the increase in gamma dose. These results have been explained on the basis of scission of the detector due to gamma irradiation.

Neutron-irradiation effects on track etching and optical characteristics of CR-39 (DOP) nuclear track detector

The effects of thermal neutron-irradiation in the neutron fluence range of (1.77–7.08) 1011 n/cm2, on the etching and optical characteristics of diethylene glycol bis allyl carbonate (dioctyl phthalate doped), CR-39 (DOP) nuclear track detector have been studied using etching and UV–visible spectroscopic techniques. The bulk etch rates determined at different fluences were found to increase with an increase in neutron fluence up to 3.54 × 1011 n/cm2, and then decrease at higher neutron fluence. The optical absorption spectra in the wavelength range of 200–800 nm were also recorded for the unirradiated and neutron irradiated samples in the above fluence range. The optical energy gaps (E g) were determined by the shift in optical absorption edges as observed by UV–visible spectra of the neutron irradiated sample, using Tauc’s expression. The UV–visible spectra results were further supported by determining the activation energies for bulk etching.

Neutron-irradiation effects on track etching characteristics of polyester nuclear track detector

The effects of reactor neutron irradiation on the etching characteristics of a locally available Garware polyester film have been studied. The effects in the neutron fluence range of 4.57×1015–1.83×1016 n/cm2 on the fission track registration efficiency and the bulk etch rate are investigated. From the results, it is found that the bulk etch rates increase with the increase in neutron fluence. The increase in etch rates can be explained on the basis of scission of the detector due to neutron irradiation which enhances the dissolution rates. From the measured bulk etch rates at different temperatures, the activation energies for bulk etching at different values of neutron fluence have also been determined. The changes induced by neutron irradiation in the polyester detector have also been studied by UV-visible spectroscopic technique. The neutron irradiation enhances the UV absorbance of the detector, which is a direct consequence of the formation of new chemical species due to scission of the detector.

Gamma-irradiation effects on track etching characteristics of polyester nuclear track detector

The effects of gamma irradiation in the dose range of 5–51 Mrad on the etching characteristics of a locally available Garware polyester film have been studied. The bulk etch rates at different doses were determined by the gravimetric method. The track etch rates at different doses were determined by measuring the track lengths. From the results, it is found that the bulk as well as the track etch rates increase with the increase in gamma dose. The increase in etch rates can be explained on the basis of scission of the detector due to gamma irradiation that enhances the dissolution rates. The sensitivity, which is the ratio of track etch rate to bulk etch rate, has been found to increase with gamma dose up to 11.5 Mrad doses and after that it decreases. From the measured bulk etch rates at different temperatures, the activation energies for bulk etching at different doses have also been determined.

Gamma ray photon-induced modifications in Triafol-TN and Triafol-BN polymeric track detectors

Photon induced modifications in Triafol-TN and Triafol-BN polymers have been studied in the dose range of 10 1–10 6 Gy at room temperature using a 60Co source. To monitor the chemical and structural changes induced by gamma rays, UV, IR, and ESR studies were carried out. Thermal studies were also conducted for understanding the effects of gamma irradiations on these polymers. Variation of track etching characteristics and activation energy for bulk etching have been studied at different gamma rays doses. The experimental results are presented and discussed.

Modifications of radiation detection response of PADC track detectors by photons

Photon induced modifications in polyalyldiglycol carbonate (PADC) track detectors have been studied in the dose range of 10 1–10 6 Gy. It was found that some of the properties like bulk-etch rate, track-etch rate got enhanced at the dose of 10 6 Gy. Activation energy for bulk-etching has been determined for different gamma doses. In order to correlate the high etch rate with the chemical modifications, UV–Vis, IR and ESR studies were carried out. These studies clearly give the indication that radiation damage results into radical formation through bond cleavage. TGA study was performed for understanding the thermal resistance of this detector. The results are presented and discussed.

Study of track registration response of makrofol-KL to 40Ar and 136Xe ions

Makrofol-KL polycarbonate nuclear track detector samples were irradiated with 40Ar (14.9 Mev/n) and 136Xe (11.56 MeV/n) at an angle of 45° from UNILAC, GSI Darmstadt, Germany to obtain track registration parameters, viz. variation of track length with etching temperature (55°, 60°, 65° and 70°C) using 6.25 N KOH as etchant, bulk and track etch rates ( V G and V T) and their respective activation energies ( E G and E T). The results show that the sensitivity decreases towards higher etching temperatures while the cone angle increases. The variation of etching rates with temperature is found to be exponential and follows the Arrhenius equation. The activation energies for bulk etching are found to be 1.18±0.08 eV and for track etching 0.66±0.04 eV and 0.71±0.04 eV for 40Ar and 136Xe ions in Makrofol-KL detector, respectively. The maximum etchable track length along with the theoretical values of maximum etchable track length and range of these ions were also obtained and were found comparable with the theoretical values within the experimental errors.

Pre-Irradiation Studies in Silicate Glass

The pre-irradiation annealing was studied in the temperature range of 100 … 350 °C for silicate glass at different annealing times. The annealing raising the tracks density. The optimum annealing temperature was 250 °C. The annealing time was found to be hardly effected at the first hundred hours. The preannealing was found to be the hardness of the silicate glass so that the bulk etching rate decreases. The activation energy for bulk etching was found to be (0.3135 eV), the annealing did not change its value.

Chemical etching characteristics of glass detectors

Abstract Chemical etching characteristics of ZnP and soda lime glasses have been studied. Both glasses have shown isotropic bulk etching in their respective etchants. The activation energies for bulk etching have also been determined in these solids. Using dilute etchant (5% HF) for soda lime glass detector we have observed that the thermal annealing process seems to be governed by two independent mechanisms which are characterised by activation energies of (22±2)kJmol -1 and (9±1)kJmol -1 at a switch over temperature of about 150°C.

Track etch rate characteristics of makrofol polycarbonate plastic detector exposed to xenon ions

Abstract Track etch rate characteristics of makrofol polycarbonate plastic detector exposed to 54 Xe 129 heavy ions of 7.5 MeV/n energy at GSI, Darmstadt have been investigated. It is observed that the bulk etching rate, V b , as well as track etching rate, V t , by keeping the concentration of the etchant (6.25N NaOH) constant, increase with the increase of etching temperature. Complete etching times have been found to be 32, 15, 9 minutes at etching temperatures of 50°C, 60°C and 65°C, respectively. The activation energies for bulk etching and track etching are determined to be 0.9 eV and 1.38 eV, respectively. The etching efficiency (η) has been found to be independent of the etching temperature. The threshold value of energy loss rate of makrofol polycarbonate has been determined from a semi-empirical relation between V t , V b and REL, and has been found to be 4.29 MeV mg -1 cm -2 . The suitability of single sheet charged particle identification method has been examined. Using this method, makrofol detector has been found to quite suitable for identifying low energy Xe ions.

Study of heavy ion tracks in different samples of cellulose nitrate

Samples of cellulose nitrate Daicel (Japanese) and cellulose nitrate (Russian) have been exposed to 40Ar ions of energy 7.4. MeV/N and 50Ti ions of energy 4.9 MeV/N respectively at an angle of 30° from the detector surface using heavy ion cyclotron facilities at JINR Dubna (Moscow), USSR. These samples have been etched in 6.25N NaOH at 60°C. The bulk etch rate V b has been found at different etching temperatures to determine the activation energies for bulk etching for these plastics. The variation of track length against etching time has been studied to find out the values of total etchable track length for these ions in these detectors. The energy loss and ranges of these ions in these plastics have been computed theoretically. By the comparison of the total etchable track length with the respective value of the theoretically computed range, the values of the critical threshold for these plastics have been found. Finally an attempt has been made to compare the response of these two plastics.

Study of 168O ion tracks in cellulose nitrate plastic detectors

Cellulose nitrate (CN) plastic track detectors exposed to 8.75 MeV/n 16 8O ions have been obtained from JINR, Dubna, USSR. The bulk etch rate of CN detectors and the track etch rate of 16 8O ions in this detector have been measured for different temperatures. From the data the activation energy for bulk etching and track etching are calculated. The range of 16 8O ions in a CN detector is determined by measuring the track length. The maximum etched track length agrees with the theoretically computed range as well as with those reported by earlier workers. From the response curve the ‘critical energy loss’ (d E/d x) c has been determined for this detector material.

Enlarging the fission fragment tracks in glass detectors by etching in weak solutions of HF—a safe etchant

The effect of etchant concentration and temperature on track revelation properties of soda glass detectors has been studied. Etch rate ratio, maximum observable diameter and the energy resolution of the fission fragment tracks of 252Cf in glasses are increased when the samples are etched in 1.25 vol% HF as compared to higher concentrations of HF and other etching solutions. The critical angle of etching is found to decrease with decrease in etchant concentration. The activation energies for bulk etching and track etching have also been estimated. Better results were obtained by using lower etching temperatures.