Optimum Etching Conditions Research Articles

Phosphate glass detectors

A phosphate glass is exposed to 10 22Ne, 18 40Ar, 22 50Ti, 26 56Fe, 36 84Kr and 54 132Xe ions from heavy ion cyclotron at JINR, Dubna (Moscow). USSR at different angles. The optimum etching conditions are determined. The energy dependence of track diameter and critical angle are studied for different heavy ions. The energy revolution of phosphate glass detectors is found to be up to ∼ 2 MeV. However, the charge resolution seems to be ∼ 9.

The measurement of airborne alpha particles using a CR-39 nuclear track detector

The characteristics of the CR-39 nuclear track detectors have been studied using the techniques of chemical etching and electrochemical etching. While electrochemical etching can be used to enlarge the track-pits for simplifying the counting procedure, it would only yield a maximum registration efficiency for alpha particle tracks up to approximately 3 MeV. The range of energy for which the registration efficiency is a maximum in the case of chemical etching is up to about 4.5 MeV alphas. The optimum etching condition for alpha tracks can be chosen at any point on the plateau extending from a thickness of 2.2 μm to about 9 μm of the layer removed from the surface of the detectors. The detectors have been applied to measurements of radon in soil air and indoor atmosphere. The result suggests that the CR-39 detectors etched chemically would have sufficient sensitivity for the survey of airborne alpha particles.

A study of bulk-etch rates and track-etch rates in CR39

The bulk-etch rate, VB of CR39 has been measured in various concentrations of NaOH and KOH (in the range 1·12 N) at temperatures from 40°C to 80°C. In addition, the track-etch, VT and the ratio V = VT/VB, of various energies of alpha particles have been measured in a similar range of etching conditions. These studies show that 6 N NaOH at 70°C represent the optimum etching conditions for CR39, within the range of the present study. An empirical method is presented for correcting V measurements on alpha particles tracks for varying amounts of surface removal. Evidence is presented for serve variations in the response of different commercial batches of CR39. Finally, it is shown that heat treatment of CR39 results in the formation of a layer of enhanced bulk-etch rate at a depth of ∼20 μm within the sheet, even in samples produced in a curing cycle designed to yield uniforme polymerisation with depth. It is suggested that this effect is a property of the polymer itself, rather than being due to experimental conditions during formation. One possible advantage of this effect is suggested.

Parameter and Reactor Dependence of Selective Oxide RIE in CF 4 + H 2

Highly selective etching of with respect to silicon and resist is obtained by reactive ion etching in . The maximum etch rate ratio depends in a sensitive way on gas residence time with etch rate ratio increasing with decreasing residence time. The reproducibility of high etch rate ratios was found to decrease with increasing pressure. The cleanliness of etching is determined by the material of the electrode and the electrode to wall area ratio. A process was developed by optimizing etching conditions and reactor design and then was tested electrically. Contact holes were etched to 0.25 μm junctions using full RIE in and buffered . The same low junction leakage and contact resistivity, 10−9 amps/cm2and 10−6 Ω‐cm2, were measured for both. Implications for scaling RIE into larger etching reactors as well as its use to pattern features at 1 μm ground rules are discussed.

On the optimisation of etching conditions for CR39 and other plastic track detectors

ABSTRACT Selection of optimum etching conditions for plastic track detectors is essential if they are to be used to best advantage. We present results of a study of the influence of etchant type, temperature and concentration, on the etching response of CR39. We conclude that 6N NaOH at 70°C gives the steepest response curve for CR39, within the range of temperatures (40 – 70 °C) and concentrations (1N-12N) studied. Other plastics are briefly discussed.

A new personnel albedo neutron dosimeter using track etch detectors — Design and performance

CR-39 and Makrofol-E have been used as fast neutron recoil track detectors. The foils were etched electrochemically at frequencies between 100 KHz and 1 MHz at field-strengths between 13 and 48 KV/cm. A conventional etching was applied before ECE to reduce the background and to improve the track formation (Hassib, 1979). The experimental arrangement was designed in such away that the foils can be etched at different temperatures up to 65 °C.Results show that the optimum etching conditions for CR-39 are 38 KV/cm field-strength at 200 KHz frequency for 15 minutes at 55 °C, and for Makrofol-E are 20 KV/cm at 500 KHz for 40 minutes at 65 °C.

Further improvement in the etching of soda glass detectors

Nascent hydrogen has been used for removing the "etch product layer" formed during etching of soda glasses in HF. The solution so developed has two advantages, viz., no heat is produced during etching, and the strength of the solution is maintained until the tracks are completely developed. Various track development properties of soda glass detectors have been studied using this solution, and the optimal etching conditions are deduced. A detailed study shows an increase in the largest observable diameter from 47.0 to 107.5 μm. The etching efficiency is found to increase from 39.8 to 48.3%, and the registration threshold angle reduces from 42.5 to 38°. The activation energies for bulk and track etching rates have been calculated. The spectrometric response of soda glass detectors to fission fragments of 252Cf has also been investigated using the new etching solution. A distinct improvement in the energy resolution of soda glass detectors is observed with the use of the new etchant.

Surface Textures of Annealed AISI 304 Stainless Steel Etched by Aqueous Ferric Chloride—Hydrochloric Acid Solutions

SUMMARYIn commercial photoetching, the etchant most commonly used for the production of perforated and recessed piece-parts and components in AISI 304 stainless steel is the FeCl3-HCl-H2O system. It has been shown that the surface texture of the etched steel is strongly dependent on etchant composition and temperature. Optimum etching conditions have been found for achieving both smooth and rough finishes. The important role of the reaction products is also discussed.

Determination of lithium and lithium-6 in solutions by the nuclear track technique

The nuclear track technique can be applied to the determination of Li and /sup 6/Li in solutions, since the triton produced by the reaction /sup 6/Li(n, ..cap alpha..) /sup 3/H is amenable to nuclear track detection. Tests were carried out to determine the effect of absorber thickness when strips of cellulose nitrate heat sealed inside various thicknesses of linear polyethylene were used as ..cap alpha.. absorbers. Absorber thicknesses between 12.5 and 28 ..mu..m produced no significant change in the triton track density. Optimum etching conditions for tracks in cellulose nitrate were found to be a 25-min etching period in 2.5N NaOH at 50 +- 0.5/sup 0/C. The lower limits of detection were found to be 100 ppM Li and 7.4% /sup 6/Li, and a linear relationship was found to exist between triton track density and lithium concentration. (BLM)

硝酸セルロースフィルムにおける放電計数特性

Basic spark counting characteristics of cellulose nitrate films 13μm thick stripped off from the polyester bases of LR-115 Type II and LR-115 Type II Stripping made by KODAK-PATHÉ in France were investigated. Detector films irradiated with α-ray were etched with NaOH solution, sandwiched between copper and aluminized sheet electrodes, and the number of sparks was counted with a scaler. Results obtained were as follows:1) Optimum etching condition was 26% NaOH solution at 50°C and etching time was 140min.2) Sparking voltages were 600V for punching and 425V for counting.3) Optimum thickness of polycarbonate sheet for a moderator was 20μm.4) The relation between irradiation time and number of counts was linear up to about 1, 000/cm2.LR-115 Type II Stripping B, which was sticked with thin LiBO2 layer on one side of the film, was also examined. It was irradiated with neutron produced from the reactor of Kinki University. Neutron fluence was estimated from spark counting of α-tracks produced by (n, α) reaction. The relation between spark counts and neutron fluence was linear between 2×108 and 4×109n/cm2.

The use of the potentiostat in the microstructural examination of uranium

The electrochemical behaviour of unalloyed uranium has been studied in the electrolytes which are used for metallographic examination of α uranium. The polarization curves and the microstructures for optimal electrolytic etching condition are given. The most favourable potential interval for α-grain morphology is between + 250 and + 350 mV, i.e. the interval where an intensive anodic dissolution begins.

Improvements in the Etching of Hard Aluminum Electrolytic Capacitor Foil

Improved procedures are described for etching hard electrolytic capacitor foil for low and intermediate voltage applications. For low voltage formation (0–100V), high capacitance was obtained by etching at high current density in a solution containing a high concentration and . For intermediate voltage formation (100–250V), optimum etching conditions consisted of a lower current density and concentration, along with the sulfate addition. In both applications, the combination of hard foil and the sulfate addition in the etch bath were particularly advantageous.

Effect of carbide heterogeneity on surface defects in high-speed steel slotting mills

1. The reason for the formation of both types of surface defects on slotting mills made of R18 steel is the carbide heterogeneity. 2. There is no connection between the formation of defects of either type and the cold working of the mills or the presence of nonmetallic inclusions. 3. Defects of the first type result from etching out of segregation bands on the surface during chemical cleaning of the mills after quenching and tempering. These defects occur a) when the etching temperature exceeds 70\dgC, b) when the etching time exceeds 20 min, c) when the hydrochloric acid concentration exceeds 7% at high temperature (70\dgC or higher). The optimum etching conditions are: a) etching bath temperature of 30–50°C; b) etching time 15–20 min; c) hydrochloric acid concentration up to 15%. 4. The probability of defects of the second type increases with the quenching temperature and the degree of carbide heterogeneity. 5. Shallow defects of both types can be removed by polishing. Deeper defects of the second type cannot be removed. The quality of the slotting mills, particularly the larger sizes, can be improved by reducing the carbide heterogeneity of the original rolled steel.