Bulk Etch Rate Research Articles

Measurement of alpha particle range in CR-39 detector using nuclear track profiles

Alpha particle is very dangerous inside the human body, so the study of its interaction parameters for alpha is very important. The Solid-State Nuclear track detector (SSNTD) CR39 can be used to study the different parameters for alpha. In this research, the bulk etch rate (VB) measured by using two different methods. The results showed that the measured of VB values by the Lmax method is very close to the values measured by the weight method. The average value of VB by Lmax method and weight method were 1.26 ± 0.02 μm h−1 - 1.28 ± 0.13 μm h−1 respectively. Also, the results for the range of alpha particles changed from 13.21 ± 0.05 μm for alpha energy 3 MeV to 34.58 ± 0.19 μm for alpha energy 5.48 MeV. The measurement of alpha particles range by the Lmax method for all energies of alpha were very closes to the theoretical range of values. The Lmax method is useful for determining all the different parameters of the path.

Detection efficiency of alpha particles using CR-39 nuclear detector- etched with BSW

In this study a new etchingsolution has been used to register alpha particles. The etching characteristics for the detection of alpha particles in CR-39 nuclear track detector using a new etching solution have been investigated. Several important parameters that control the track formation such as, the bulk etch rate, the track etching rate, and the critical angle have been measured. The dependence of etching efficiency and sensitivity upon the volume of 1- Butanol and temperature has been studied. The effect of etching time, the volume of 1-Butanol and the temperature upon the etching parameters have been investigated. Also, the enhancement in the etching efficiency with the decrease in the volume of 1-Butanol is more pronounced. The new etching solution has been demonstrated to be a fast etching solution. Results of irradiation of CR-39 detector with alpha particles and the etching characteristics, along with recording alpha particles tracks in the detector are also addressed and thoroughly discussed.

Maximum Track length Approach for Estimation of Bulk Etch Rate of CR-39 Detector by Means of Track Diameter-Length Correlation

In this paper, we use maximum track length approach depending on track diameter-length (D-L) correlation as another way to estimate directly from empirical measurements of the track diameters or lengths without resorting to other methods. The lengths of the tracks have been extracted using the (D-L) correlation which relied on the measurement of the opening’s diameter of the etched tracks, in addition to using the Track-Test program . 241Am (1μCi) source was used to irradiate the plastic detector CR-39 with alpha particles of energies of (3.5-5.3) MeV by means of normal incidence. The irradiated detectors were treated by a chemical etchant for distinct intervals of time using an aqueous NaOH solution of 6 N preserved at temperature (70±1) . An empirical formula was applied to calculate . The formula relies on two parameters, the maximum length of the track and its saturation time . We have seen that the magnitude of is equal to 1.407 , which can be regarded as compatible with the values indicated by others using different methods. It has been noticed that the maximum length of the etched tracks is directly proportional to alpha energy while exponentially to saturation time of the length.

Influence of pre-exposure thermal annealing on etch rates of CR-39 nuclear track detectors: New findings

The influence of pre-exposure thermal annealing on CR-39 etch rates has been studied here thoroughly. Annealing experiments were conducted on CR-39 detectors prior to their exposure to 252Cf fission fragment source. The bulk etch rates were measured by using the weight loss method (WLM) and the fission track diameter method (FTDM). We report here a new quantitative result that the bulk etch rate decreases from the original surface of each CR-39 detector initially rapidly and then more slowly along the depth mimicking the exponential trend. These quantitative results are more pronounced for cases of higher annealing temperatures and larger annealing time intervals. This exponential drop of the bulk etch rate suggests that the interior of the CR-39 detector material is almost out of pre-exposure annealing. Our results reveal that the etch rates and the registration properties of the heavy ions are considerably altered in the near-surface layer of the annealed PADC.

Influence of UV irradiation on the diameters and depths of alpha-particle tracks in CR-39 detectors

In this paper, we investigate the impact of ultraviolet (UV) exposure on the bulk etch rate (Vb), track etch rate (Vt), and detector sensitivity of a CR-39 nuclear track detector. The study involves measuring the depths and diameters of alpha particle tracks in the CR-39 detector. The detectors were irradiated with alpha-particles with energy of 3.5 MeV after/or before being exposed to UV radiation at 366 nm for 6 h. The detectors were etched in a 6.25 N NaOH solution at 70 °C for periods of 1–7 h. The results showed that both Vb and Vt for CR-39 exhibited an enhancement when exposed to UV, where, the alpha-particle track diameters and depths increased with UV exposure. Moreover, the study revealed that the track formation time is decreased when the CR-39 detector was irradiated with UV light.

Etched track profiles for relativistic 7 GeV silicon and 17.48 GeV Nickel ions in PADC detector: The case study of convex track walls

650 μm thick PADC foils are exposed to 7 GeV Silicon and 17.48 GeV Nickel accelerated ions at particle fluence of about 1000 cm−2. The relativistic ions passed through the entire thickness of the PADC foils and created latent tracks that were etched sequentially under strong etching conditions (NaOH + ethanol). For each time sequence, etched track profiles were found by carefully polishing the detector edge, and then imaged in order to measure their geometrical parameters (diameter and length). Track wall curvature study allows for better understanding of the physico-chemical interactions undertaken during the etching process. Etched track profiles have the distinctive feature of presenting concave walls near to the track aperture. Such special feature is likely to be due to a depth dependent variation of the bulk etch rate (Vb). This depth dependence is investigated and discussed. A simulation program has been written based on the variational principle, it uses experimentally determined variable Vb and a constant specific track etch rate (Vt). Simulations results are in good agreement with experimental micrographs both qualitatively and quantitatively. Such case study may show promise as a means of fabricating controlled shape pores in polymer membranes.

Alpha track registration and revelation in CR-39 using new etching method for ultratrace alpha radioactivity quantification in solution media

Abstract A CR-39 based method was developed for measuring the ultra-trace alpha radio activities in aqueous samples having curie levels of γ/β-radio activities. The chemical etching method was optimized to reveal the alpha tracks in CR-39. This new chemical etching method involved the use of a phase transfer catalyst tetraethylammonium bromide which reduced the track revelation induction time without deteriorating the track-etch parameters. The alpha track-etch parameters such as bulk-etch rate, track-etch rate, induction time, and the critical angle of alpha track registration were measured at 60 and 70 °C, with and without using a phase transfer catalyst in the chemical etching for the comparison and optimization. The track registration efficiency of CR-39 in the solution medium was measured using the samples having known alpha activity of mixPu, and value obtained was found to be (4.42 ± 0.12) × 10−4 cm. The registration efficiency value thus obtained was corroborated with the expected efficiency expected from the calculated range of alpha particles in the solution. This CR-39 based method was employed to quantify the alpha activity, as low as 0.2 Bq mL−1, in the aqueous radiopharmaceutical samples having the curie levels of γ/β radio activities.

Strong etching formulation (time and rate) for PADC with deep depth bulk etch rate study

Aqueous NaOH with ethanol (strong) etchant is widely used. It shortens etching time effectively compared to normal etching conditions (6.25N NaOH at 70 °C). Two equations have been proposed to calculate the etching time with NaOH molarity and ethanol volume. Another two empirical equations were introduced for estimating the bulk etch rates of PADC etched in strong etchant. Up to now, there were no such equations available in the literature that can predict etching time and Vb of PADC with etchant molarity and ethanol volumes. The proposed equations were compared to fundamental Vb models stemming from literature. Fast etching enables the follow-up of bulk etch rate variation versus depth in the detector material up to ≈80μ m. In agreement with previous studies, an equation is given which allows such variations to be expressed under the form of a reciprocal bulk etch rate normalized to depth (i.e., removed layer).

Updates to TRACK_TEST and TRACK_VISION Computer Programs.

The computer programs TRACK_TEST and TRACK_VISION were previously developed to model profiles and optical appearances of tracks developed in solid-state nuclear track detectors. The programs were based on a track development model that involved the bulk etch rate Vb and the track etch rate Vt or the V function (i.e., Vt/Vb). The present work reported our work to update and modify these two programs. In the revised TRACK_TEST, two new V functions were added and enabled. Sample results for the CR-39 detector obtained using the three original and the two new V functions were compared. Discrepancies were within ~10% and <14% for incident alpha-particle energies of 1 MeV and >1 MeV, respectively. Another major revision of TRACK_TEST was to enable calculations for the Makrofol detector. In the revised TRACK_VISION, the two new V functions, as well as the option for the Makrofol detector, were also added. The experimental results on the Makrofol detectors were obtained (irradiated with 3.6-MeV alpha particles under normal incidence and then etched to achieve a removed detector thickness of 30 μm) for comparisons with the modeled results using the revised TRACK_VISION. The track diameters obtained from the experiment and model were 24.7 and 23.2 μm, respectively. Moreover, a bright area in the central parts, together with an outer dark ring, were present in both the simulated and experimental tracks. The track-opening diameters and the general optical appearances of the tracks were in good agreement.

Low energy alpha particle tracks in CR-39 nuclear track detectors: Chemical etching studies

The widely known CR-39 nuclear track detectors (NTDs) have been used to investigate the etch pits formed by alpha particles from a 241Am source moderated to 1–2 MeV. The efficiencies of two available CR-39 plastic detectors, Lantrak and Baryotrak, have been studied as a function of the chemical etching time. The chemical etching solutions of the NaOH, KOH and NaOH+ethyl alcohol at 70 and 80°C have been applied to build etch pit diameter growths as well as density curves. The obtained growth curves of etch pit diameters have been compared under these different etching conditions, showing similar general trends for Baryotrak and Lantrak detectors for etching at 70°C. A slight divergence of the curves have been observed at 80°C for etching times above 400 min, revealing a small variation in the bulk etch rates between the two detector types. The etch pit density curves for both detectors have also been studied, showing a plateau for all etching conditions except for NaOH+ethyl alcohol at 80°C, in which there is a significant decrease in density after ≈ 600 min of etching. The results obtained with the protocols described in detail in this work show the pertinent precautions to be adopted in the chemical treatment of NTDs for the detection of alpha particle at low energies. In particular, the quantitative results highlight the limits of linear growth of pits and induction etching time for etch pits with diameters D=0 μm (EIT0) and D=1 μm (EIT1).

Development of alpha tracks measurement with thermal oven as an etching technique for SSNTDs

Abstract In the present work, Thermal oven as a heating technique in chemical etching process has been tested to investigate the track density and compares with a traditional technique water bath (WB). Thermal oven induced chemical etching has been employed in reducing the etching duration. Two solid-state nuclear track detectors (SSNTDs) CR-39 and LR-115 are utilized in this comparison. Detectors are exposed to 226Ra alpha source (5 µ ci). Several pieces of CR-39 and LR-115 detectors were exposed to 226Ra source at three different times of exposure (5, 10 and 15sec). Chemically Etching carry out with NaOH alkaline solution (6.25 N) at 70 °C for CR-39 and (2.5 N) at 60 °C for LR-115. For (5, 10 and 15sec) exposure time, the estimated maximum track densities of CR-39 detector at 90 min for thermal oven compared with 120 min for water bath. LR-115 detector maximum track densities were founded at 40 min compared with 50 min for the water bath technique. Finally, the etching parameters (the diameter of the tracks (D), etching efficiency (ɳ), bulk etching rate (VB), track etching rate (VT), and the sensitivity (V)) were calculated and compared.

Bulk Etch Rate of LR 115 Polymeric Radon Detector

In this study, we used strippable LR 115 type 2 which is a Solid State Nuclear Track Detector (SSNTD) widely known for radon gas detection and measurement. The removed thickness of the active layer of samples of this SSNTD, were determined by measuring the average initial thickness (before etching) and residual thickness after 80 to 135 minutes chemical etching in the standard conditions, using an electronic comparator. These results allowed the calculation of the bulk etch rate of this detector in a simple way. The mean value obtained is (3.21 ± 0.21) μm/h. This value is in close agreement with those reported by different authors. It is an important parameter for alpha track counting on the sensitive surface of this polymeric detector after chemical etching because track density depends extremely on its removed layer. This SSNTD was then used for environmental radon gas monitoring in Côte d’Ivoire.

Characterization of Makrofol[formula omitted] DE 1-1 (bisphenol-A polycarbonate) as SSNTD and its application in the alpha particle detection

Makrofol® DE 1-1 (bisphenol-A polycarbonate) was characterized as a solid state nuclear track detector (SSNTD) as well as for alpha particle detection. The bulk etch rate of the Makrofol® DE 1-1, at different etchant concentrations and temperatures, was found to be homogenous. The visible light absorbance measurements of the etched Makrofol® DE 1-1 at different etching conditions indicated that the lowest visible light absorbance occurs at the etching conditions of 75% 6 N KOH+25% C2H5OH and a temperature of 50∘C. The bulk etch rate activation energy EB increased from (0.59±0.05) eV to (0.76±0.05) eV for Makrofol® DE 1-1 etched in KOH and 25% 6 N KOH+75% C2H5OH, respectively. Before alpha particle tracks overlapping, the alpha track density in Makrofol® DE 1-1 is linearly correlated with the exposure time to alpha particles. The alpha particles track diameter was found to be a non-monotonic function of the alpha particle energy. The range of alpha particles in Makrofol® DE 1-1, which is a monotonic function of alpha particle energy, was determined using the over-etched track technique. The range-energy relationship of a perpendicularly incident alpha particle in a Makrofol® DE 1-1 detector can be used for the determination of the alpha particle energy over a wider energy range than with the etch pit diameter-energy relationship.

Bulk etch rates of CR-39 at high etchant concentrations: diffusion-limited etching

Systematic CR-39 bulk etching experiments were conducted over a wide range of concentrations (2–30 N) of NaOH-based etchant. Critical analysis and a deep discussion of the results are presented. A comprehensive nuclear track chemical etching data bank was developed. Three regimes of CR-39 bulk etching were identified. Regime I spans etchant concentrations from 2 to 12 N. Regime II spans concentrations from 12 to 25 N. We call this the dynamic bulk etching regime. Regime III is for concentrations greater than 25 N. In this regime, the bulk etch rate is saturated with respect to the etchant concentration. This classification is discussed and explained. The role of ethanol in NaOH-based etchants is explored and discussed. A parameter called the "reduced bulk etch rate" is defined here, which helps in analyzing the dependence of bulk etching on the amount of ethanol in the etchant. The bulk etch rate shows a natural logarithmic dependence on the density of ethanol in the etchant.

Validity of the diameter-length method for determining the bulk etch rate of a CR-39 detector

This article tests the feasibility of using the diameter-length (Le-D) technique to determine the bulk etch rate (Vb) in a CR-39 nuclear track detector. The detector was irradiated with alpha particles energies: 5.3, 4.7, 4.1 and 3.5 MeV, which were emitted from a 241Am source. The detector was etched in a 6.25 N NaOH solution at 60 °C for periods of 1–10 h. The average Vb found by means of the (Le-D) method is approximately 0.76 ± 0.05 µm/h, which is consistent with the result found separately by the thickness-measurement method (i.e. 0.836 ± 0.06 µm/h). Moreover, the results show that the Vb of the CR-39 detector is independent of the alpha energies. This can pave the way for the use of the (Le-D) method as a reliable alternative method for measuring the bulk etch rate.

Finding Bulk etch rate VB using the maximum value of the Lmax effect using practical diameters calculated from the falling alpha particles on the CR-39 nuclear track detector

A lot of research was focused on studying the engineering shape of the impact and its development and finding its parameters. It was based on pictures of the side effects of the effects formed in the detector as a result of the detector’s etching. Obtaining pictures of the side effects of the effects to measure their lengths is a difficult process compared to its diameters. There are many methods used to find Bulk etch rate VB including gravimetric method or thickness difference; but we will use in this research an alternative method to find VB which is the maximum value method for saturation of the effect length “Lmax-method”. Using the source Am241 (1μCi) emitting alpha particles in irradiation of the PDAC CR-39 irradiation With MeV energies (2.3,3.3,4.3), the detectors etching by NaOH aqueous solution at different concentrations (N: 6,7,8) at a temperature of 70±1 °C, we suggested in our research a D-Le calibration method that is based on direct experimental measurement of the diameters of the projected effects in Detector instead of lengths. An empirical relationship was used to find VB, which depends on the maximum values of saturation of effects lengths and their saturation times. The results we obtained for VB values at the concentrations used were (1.199,1.490,2.184) μm h−1 in order and they correspond well to the values resulting from different methods, it is observed The Bulk etch rate increases with the concentration of the abrasive solution, and the maximum values of saturation of the effect length are directly proportional to the energy of the bombing particles and the time of saturation of the impact lengths.

Bulk etch rates of CR-39 nuclear track detectors over a wide range of etchant (NaOH aqueous solution + ethanol) concentrations: measurements and modeling

Bulk etch rates for CR-39 detector were measured and studied over a wide range of NaOH aqueous solution concentrations (2–20 N) with different ethanol volumes. This wide range of etching concentration is divided into two major parts: soft etching part (2–8 N NaOH) and dense etching part (8–20 N NaOH). This classification will be explained and discussed. The etchant viscosity in the two parts was measured and compared. The effect of ethanol in both parts was deduced through a new parameter called ‘reduced bulk etch rate’. This new parameter helps in analyzing the dependence of bulk etching on the amount of ethanol in the etchant. It was found that conducting the etching process in the dense etching part reduces the etching time significantly. Etching in the dense part is not far away from equilibrium where Mushtaq, Multi-hit and Arrhenius fitting equations are applicable. The fitting of measured bulk etching data was carried out in the soft (low), dense (high) and the whole etching concentration ranges. Generally, a good agreement was found between physical data and model calculations.

The along-track etching structure of fission tracks in apatite: Observations and implications

Interpretation of apatite fission-track length data rests on the assumptions that etching fully reveals latent tracks, and that laboratory annealing of induced tracks constitutes a good proxy for geological annealing of spontaneous tracks. Recent work using improved step-etching procedures questions both of these assumptions. Step etching experiments interrogating the etching structure of tracks near and beyond their tips have shown that tracks are often not etched to their full extent of latent track damage in a standard single-step, 20-s etch, and that the etching structure in this outer region differs between fossil and induced tracks. In this study, we develop a more complete picture of track revelation for fossil and unannealed and annealed induced tracks in Durango apatite. Using first steps as early as 10 s after the beginning of etching, we discern differences in etching structure between various track types, and document a gradual fall-off in etching velocity from the track interior toward its tips. When effective etching time is constrained by selecting earlier-etching confined tracks for later analysis, mean lengths are longer, but length dispersion is not diminished. Although some proportion of unannealed tracks are under-etched after 20 s of etching, with increased levels of annealing the probability of an induced track being fully etched increases. We use an etch-anneal-etch procedure, consisting of partially etching tracks, annealing the apatite grains, and then continuing etching, to establish bulk etching rates at track tips. Bulk etching is effectively isotropic, as is etching velocity in the central portions of tracks, away from their tips. We use our data to compare two end-member possibilities for along-track etching structure, which provides a first step toward a deeper understanding of annealing and development of a more robust standard etching protocol.

Effects of He–Ne laser on etching parameters of lexan (polycarbonate) plastic track detector irradiated with fission fragments

This research work investigates the effects of He–Ne laser (115 and 287 J/cm2 fluence) radiation on the etching parameters like bulk etch rate VB, track etch rate VT, Sensitivity S, critical angle θC and efficiency η of Lexan plastic track detector, irradiated with fission fragments from 252Cf source. The changes in etching parameters due to He–Ne laser in the fluence range of 0, 115, and 287 J/cm2 at different temperatures (328–348 K) have been discussed in detail. Bulk and track etch rates are observed to vary with He–Ne laser fluence both in case of pre-exposed and post-exposed detectors as compared to un-exposed Lexan plastic detector. Both bulk and track etch rates follow Arrhenius equation. Based on these results, important inferences regarding activation energies associated with bulk and track etch rates have been made. Sensitivity, critical angles and efficiencies of detector material also reveal significant facts about the changes in properties due to He–Ne laser on the Lexan plastic detector. A comparative study is performed on the effects of coherent/in-coherent electromagnetic radiation on nuclear track detectors. The activation energies of bulk and tack etching for commonly used nuclear track detectors is also reported.

Impact of infrared radiation on track etching parameters of Lexan track detector to fission fragments from 252Cf source

In this research work, the impact of infrared (IR) radiation on the etching parameters like bulk etch rate VB, track etch rate VT, Sensitivity S, Critical angle of etching θC and track registration efficiency η of Lexan track detector, irradiated to fission fragments from 252Cf source, were investigated. The changes in etching parameters due to infrared radiation for 0, 12 and 24 h at different temperatures (328–348 K) are discussed based on chain scission and cross-linking mechanisms. Bulk and track etch rates increase with infrared radiation in case of post-exposed as compared to un-exposed while sensitivity slightly decreases for 12 h exposure with infrared radiation but slightly increases for 24 h exposure with infrared radiation as compared to un-exposed. On the other hand, bulk and track etch rates decrease with infrared radiation in case of pre-exposed as compared to un-exposed while sensitivity slightly increases. Critical angles increase and track registration efficiency decreases with etching temperatures. Activation energies for bulk and track etching rates have been determined by fitting Arrhenius equation to the experimental data of bulk and track etch rates which show a decrease in bulk activation energies in case of post-exposed but slightly increase in case of pre-exposed as compared to un-exposed Lexan track detectors. Track activation energies show the same trend as for bulk etch rate.