Bulk Etch Research Articles

Impact of X-rays on fission fragments track etch parameters in Lexan detector as analyzed by FTIR spectroscopy

Irradiation effects of X-rays (45 min and 90 min) on track etch parameters of Lexan polycarbonate detectors have been studied with respect to structural behavior using Fourier transform infrared spectroscopy (FTIR) spectroscopy. Pre-exposure and post-exposure of X-rays bring significant changes in track etch parameters (bulk etch rate (BER) and track etch rate (TER)) of Lexan polycarbonate detectors at 55[Formula: see text]C to 75[Formula: see text]C. The energy carried by X-rays results in hardening due to cross-linkage and softening due to chain scission of Lexan polycarbonate detectors. BERs and TERs follow Arrhenius equations, and slopes of graph reveal information about activation energy of BERs and TERs. Bulk activation energies calculated are found to be 0.91 eV (unexposed), 0.94 eV (pre-exposed 45 min), 0.96 eV (pre-exposed 90 min), 0.88 eV (post-exposed 45 min) and 0.86 eV (post-exposed 90 min) and are also found to be in agreement with available literature. Track activation energies (TAEs) calculated are found to be 0.74 eV (unexposed), 0.75 eV (pre-exposed 45 min), 0.77 eV (pre-exposed 90 min), 0.74 eV (post-exposed 45 min) and 0.73 eV (post-exposed 90 min). Post-exposure of X-rays for 90 min on Lexan polycarbonate detectors results in enhancement of sensitivity and recorded highest (12.72) at 65[Formula: see text]C. The critical angle of Lexan polycarbonate detectors is also affected by post-exposure of X-rays for 90 min and found maximum (38.59[Formula: see text] at 75[Formula: see text]C. FTIR spectra confirm cross-linkage in Lexan polycarbonate detector during 3 h exposure of fission fragments (FFs) of [Formula: see text]Cf as compared to 2 h exposure.

The Impact of Laser on the Activation Energy and Sensitivity of CR-39 Detector

The influence of laser radiation on bulk and etch rates, and as well detector sensitivity, before and after being irradiated with alpha particles at 5 MeV emitted from a 241Am source, are examined at different etching temperatures (65, 67, 69, 71, 73, 75, 77, 79 ,81, 83, and 85)C in this paper. A laser source with a wavelength of 480 nm and a pulse energy of 50 mJ/pulse at a repetition rate of 9 Hz was used to investigate the activation energy of a CR-39 polymer. The rates of bulk etch, Vb, and track etch, Vt, slightly increase with laser radiation. Whereas sensitivity decreases as temperature increases, besides, alpha-laser samples have quite better sensitivity than other samples. The activation energies of the bulk etch rates, Eb, are equivalent to 0.94 ± 0.07, 0.88 ± 0.05, and 0.95 ± 0.06 eV for laser-alpha, alpha-laser, and no laser samples, respectively. While, the activation energies associated with track etch rate, Et, for the CR-39 samples under study are 0.86 ± 0.04, 0.77 ± 0.03, and 0.76 ± 0.03 eV. The results manifest that laser exposure has a slight influence on activation energies of bulk etch rate within experimental uncertainties of the CR-39 samples. Additionally, the CR-39 set of laser-alpha samples reveals that Et is increased based on the cross-linking process. The increase in Et relates to hardening of the detector material, which has several uses, specifically in radiation detection.

Defect engineering of water-dispersible g-C3N4 photocatalysts by chemical oxidative etching of bulk g-C3N4 prepared in different calcination atmospheres

• Water-dispersible g-C 3 N 4 is prepared by chemically oxidative etching of bulk g-C 3 N 4 . • Bulk g-C 3 N 4 is polymerized in different calcination atmospheres of air, CO 2 , or N 2 . • Water-dispersible g-C 3 N 4 from the N 2 (NTw) shows the highest photodegradation rate. • NTw contains abundant O- and S- functional groups and N-deficiency on the g-C 3 N 4 . • The best photocatalytic performance of NTw is ascribed to the slowest recombination. In this study, water-dispersible graphitic carbon nitride (g-C 3 N 4 ) photocatalysts were successively prepared through the chemically oxidative etching of bulk g-C 3 N 4 that was polymerized thermally in different calcination atmospheres such as air, CO 2 , and N 2 . The different calcination atmospheres directly influenced the physicochemical and optical properties of both bulk and water-dispersible g-C 3 N 4 , changing the photocatalytic degradation behavior of methylene blue (MB) and tetracycline hydrochloride (TC-HCl) for water-dispersible g-C 3 N 4 . The bubble-burst process in the thermal polymerization of thiourea produced defective edges containing C=O groups that preferred substituting the C-NH x groups over bulk g-C 3 N 4 . In the oxygen-free N 2 atmosphere among the different calcination atmospheres, more C=O functional groups were generated on the defective edges of bulk g-C 3 N 4 , resulting in the highest N vacancy of the tri-s-triazine structure. During the successive chemical oxidation, S- or O-containing functional groups were introduced onto water-dispersible g-C 3 N 4 . The water-dispersible g-C 3 N 4 photocatalyst from the oxygen-free N 2 atmosphere (NTw) contained the most O- and S- functional groups on the g-C 3 N 4 surface. Consequently, NTw exhibited the highest photocatalytic activity in the MB and TC-HCl photodegradation because of its slowest recombination process, which was ascribed to the unique surface properties of NTw such as abundant functional groups on the defective edges and N-deficient property.

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.

Enabling Fast Na+ Transfer Kinetics in the Whole-Voltage-Region of Hard-Carbon Anodes for Ultrahigh-Rate Sodium Storage.

Efficient electrode materials, that combine high power and high energy, are the crucial requisites of sodium-ion batteries (SIBs), which have unwrapped new possibilities in the areas of grid-scale energy storage. Hard carbons (HCs) are considered as the leading candidate anode materials for SIBs, however, the primary challenge of slow charge-transfer kinetics at the low potential region (<0.1V) remains unresolved till date, and the underlying structure-performance correlation is under debate. Herein, ultrafast sodium storage in the whole-voltage-region (0.01-2V), with the Na+ diffusion coefficient enhanced by 2 orders of magnitude (≈10-7 cm2 s-1 ) through rationally deploying the physical parameters of HCs using a ZnO-assisted bulk etching strategy is reported. It is unveiled that the Na+ adsorption energy (Ea ) and diffusion barrier (Eb ) are in a positive and negative linear relationship with the carbon p-band center, respectively, and balance of Ea and Eb is critical in enhancing the charge-storage kinetics. The charge-storage mechanism in HCs is evidenced through comprehensive in(ex) situ techniques. The as prepared HCs microspheres deliver a record high rate performance of 107 mAh g-1 @ 50 A g-1 and unprecedented electrochemical performance at extremely low temperature (426 mAh g-1 @ -40 °C).

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.

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).

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.

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.

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.

A novel silicon etching method using vapor of tetramethylammonium hydroxide solution

Silicon bulk etching is an important part of micro-electro-mechanical system (MEMS) technology. In this work, a novel etching method is proposed based on the vapor from tetramethy-lammonium hydroxide (TMAH) solution heated up to boiling point. The monocrystalline silicon wafer is positioned over the solution surface and can be anisotropically etched by the produced vapor. This etching method does not rely on the expensive vacuum equipment used in dry etching. Meanwhile, it presents several advantages like low roughness, high etching rate and high uniformity compared with the conventional wet etching methods. The etching rate and roughness can reach 2.13 µm/min and 1.02 nm, respectively. Furthermore, the diaphragm structure and Al-based pattern on the non-etched side of wafer can maintain intact without any damage during the back-cavity fabrication. Finally, an etching mechanism has been proposed to illustrate the observed experimental phenomenon. It is suggested that there is a water thin film on the etched surface during the solution evaporation. It is in this water layer that the ionization and etching reaction of TMAH proceed, facilitating the desorption of hydrogen bubble and the enhancement of molecular exchange rate. This new etching method is of great significance in the low-cost and high-quality micro-electromechanical system industrial fabrication.

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.