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Sample records for electrochemically etched cr-39

  1. Personnel neutron dosimetry using electrochemically etched CR-39 foils

    International Nuclear Information System (INIS)

    Hankins, D.E.; Homann, S.; Westermark, J.

    1986-01-01

    A personnel neutron dosimetry system has been developed based on the electrochemical etching of CR-39 plastic at elevated temperatures. The doses obtained using this dosimeter system are more accurate than those obtained using other dosimetry systems, especially when varied neutron spectra are encountered. This Cr-39 dosimetry system does not have the severe energy dependence that exists with albedo neutron dosimeters or the fading and reading problems encountered with NTA film. The dosimetry system employs an electrochemical etch procedure that be used to process large numbers of Cr-39 dosimeters. The etch procedure is suitable for operations where the number of personnel requires that many CR-39 dosimeters be processed. Experience shows that one full-time technician can etch and evaluate 2000 foils per month. The energy response to neutrons is fairly flat from about 80 keV to 3.5 MeV, but drops by about a factor of three in the 13 to 16 MeV range. The sensitivity of the dosimetry system is about 7 tracks/cm 2 /mrem, with a background equivalent to about 8 mrem for new CR-39 foils. The limit of sensitivity is approximately 10 mrem. The dosimeter has a significant variation in directional dependence, dropping to about 20% at 90 0 . This dosimeter has been used for personnel neutron dosimetry at the Lawrence Livermore National Laboratory for more tha 18 months. 6 refs., 23 figs., 2 tabs

  2. Sensitivity of chemically and electrochemically etched CR 39 polymers to the neutrons of AmBe source

    International Nuclear Information System (INIS)

    Turek, K.; Spurny, F.; Dajko, G.; Somogyi, G.

    1981-01-01

    Seven samples of polymers by different manufacturers were used in a study of the sensitivity of CR 39 polymers to Am-Be neutrons. In the polymer, proton tracks for a relatively broad energy range can also be recorded. The following characteristics were studied: the sample background for different etching methods, the dependence of sensitivity on the etched thickness and on neutron fluence, the effect of type and thickness of external proton emitters, and the effect of the choice of electric parameters on the resulting sensitivity in electrochemical etching. Good results were obtained when chemical and electrochemical etching was used in combination. It was found that with electrochemical etching, sensitivity decreases for neutron fluence exceeding 10 8 cm -2 . The sensitivity of the studied CR 39 polymer samples only little differed. When the most sensitive polymer was used, the minimum dose equivalent in the human body for Am-Be neutrons which could be determined using combination etching was 0.4 mSv (ie., 40 mrems). (B.S.)

  3. Use of CR-39 foils for personnel neutron dosimetry: improved electrochemical etching chambers and procedures

    International Nuclear Information System (INIS)

    Hankins, D.E.; Homann, S.G.; Westermark, J.

    1986-01-01

    The electrochemical etching procedures for the new dosimetry system that uses foils of CR-39 plastic has been improved. During 1985, the etching chambers were modified to correct several problems and the changes to the etching procedures were studied, which gave a more uniform track density and size. The currently recommended etch parameters are given. A new generation of CR-39 material from the manufacturer proved to have a considerably lower background track density and a higher sensitivity; the new foils are also more uniform in thickness, which eliminates the need to numerically compensate for thickness variations. The energy dependence of the CR-39 using monoenergetic neutrons from accelerators at Battelle Northwest Laboratories and at Los Alamos National Laboratory was determined. Some variation was found in the energy dependence, but it is believed this was caused by changes in the etching procedures and by uncertainties in the fluences of the neutrons from the accelerators. A means by which the counting of CR-39 tracks may be automated is suggested; this would be very useful in adapting the CR-39 dosimetry system to large-scale use

  4. Characteristics of neutron-irradiated CR-39 foils treated by sequential chemical and electrochemical etching

    International Nuclear Information System (INIS)

    Somogyi, G.; Dajko, G.; Turek, K.; Spurny, F.

    1982-01-01

    The density of background spots revealed by chemical (CE) and electrochemical (ECE) etching and by their sequential application (CE + ECE) has been measured in several sorts of CR-39 material. The trends in the variation of sensitivity to Am-Be neutrons have been determined in CR-39 sheets covered by thick proton-radiator, when changing the field strength, frequency, etchant concentration, pre-etch duration and the fluence of neutrons. The results are analyzed in order to find out an optimum set of experimental parameters which may be proposed to attain high registration sensitivity to neutrons. (author)

  5. Personnel neutron dosimetry applications of track-size distributions on electrochemically etched CR-39 foils

    International Nuclear Information System (INIS)

    Hankins, D.E.; Homann, S.G.; Westermark, J.

    1988-01-01

    The track-size distribution on electrochemically etched CR-39 foils can be used to obtain some limited information on the incident neutron spectra. Track-size distributions on CR-39 foils can also be used to determine if the tracks were caused by neutrons or if they are merely background tracks (which have a significantly different track-size distribution). Identifying and discarding the high-background foils reduces the number of foils that must be etched. This also lowers the detection limit of the dosimetry system. We have developed an image analyzer program that can more efficiently determine the track density and track-size distribution, as well as read the laser-cut identification numbers on each foil. This new image analyzer makes the routine application of track-size distributions on CR-39 foils feasible. 2 refs., 3 figs

  6. An energy and direction independent fast neutron dosemeter based on electrochemically etched CR-39 nuclear track detectors

    International Nuclear Information System (INIS)

    James, K.; Matiullah; Durrani, S.A.

    1987-01-01

    A computer-based model is presented, which simulates the dose equivalent response of electrochemically etched CR-39 to fast neutrons of various energies and angles of incidence. Most previous calculations of the response of CR-39 have neglected the production of recoiling oxygen and carbon nuclei as well as α particles in the CR-39. We calculate that these 'heavy recoils' and α particles are the major source of electrochemically etchable tracks in bare CR-39 at neutron energies above approx. 2 MeV under typical etching conditions. Our calculations have been extended to predict the response of CR-39 used in conjunction with various combinations of polymeric front radiators and we have determined the radiator stack configuration with produces the most energy independent response. Again, the heavy recoils and α particles cannot be neglected and, for energies above approx. 2 MeV, these produce typically about 20% of the total response of our optimum stack. This type of fast neutron dosemeter is, however, strongly direction dependent. We have integrated the response over all appropriate angles to predict the dose equivalent response for two representative neutron fields, and we suggest a method for minimising the angular dependence. (author)

  7. Electrochemical development of particle tracks in CR-39 polymer dosimeter

    International Nuclear Information System (INIS)

    Hadlock, D.E.; Parkhurst, M.A.; Yang, C.S.; Groeger, J.; Johnson, J.R.; Huang, S.J.

    1985-09-01

    Electrochemical etching of CR-39 polymeric track etch neutron detectors results in proton-recoil tracks can be distinguished from background tracks much better than tracks developed solely by chemical etching. A newly designed and constructed electrochemical etching apparatus allows large numbers of dosimeters to be processed simultaneously with consistent results. Many processing systems have been developed for chemical and electrochemical etching of the track etch dosimeters. Three systems specifically show great promise and are being studied extensively

  8. Long-term measurements of equilibrium factor with electrochemically etched CR-39 SSNTD

    International Nuclear Information System (INIS)

    Ng, F.M.F.; Nikezic, D.; Yu, K.N.

    2007-01-01

    Recently, our group proposed a method (proxy equilibrium factor method) using a bare LR 115 detector for long-term monitoring of the equilibrium factor. Due to the presence of an upper alpha-particle energy threshold for track formation in the LR 115 detector, the partial sensitivities to 222 Rn, 218 Po and 214 Po were the same, which made possible measurements of a proxy equilibrium factor F p that was well correlated with the equilibrium factor. In the present work, the method is extended to CR-39 detectors which have better-controlled etching properties but do not have an upper energy threshold. An exposed bare CR-39 detector is first pre-etched in 6.25 N NaOH solution at 70 o C for 6 h, and then etched electrochemically in a 6.25 N NaOH solution with ac voltage of 400 V (peak to peak) and 5 kHz applied across the detectors for 1 h at room temperature. Under these conditions, for tracks corresponding to incident angles larger than or equal to 50 deg., the treeing efficiency is 0% and 100% for incident energies smaller than and larger than 4 MeV, respectively. A simple method is then proposed to obtain the total number of tracks formed below the upper energy threshold of 4 MeV, from which the proxy equilibrium factor method can apply

  9. STUDYING THE STRUCTURAL, OPTICAL, CHEMICAL AND ELECTROCHEMICAL ETCHING CHANGES OF CR-39 FOR DOSEMETRIC APPLICATIONS.

    Science.gov (United States)

    Zaki, M F; Elshaer, Y H; Taha, Doaa H

    2017-12-01

    The present work shows the induced modification of the structural, optical, chemical etching and electrochemical etching parameters of CR-39 irradiated with alpha-particles. CR-39 polymer track detectors were irradiated with different fluences (1.62 × 106, 2.72 × 106, 3.82 × 106 and 5.21 × 106 particles/cm2) of alpha-particles using 241Am source. The structural and optical properties were measured by FT-IR spectroscopy, X-ray diffraction and UV/Vis spectroscopy, respectively. The FT-IR spectra reveal that no major changes in the typical functional groups of irradiated polymer detectors. The X-ray diffraction patterns show that a broad band in the region of 12° 27°, which refers to the presence of the combination of amorphous and crystalline phases. UV/Vis responses of irradiated polymer track detectors exhibit a single absorption band in the range of 254-352 nm that is correlated to the occurrence of electronic transition. Also, the changes in the chemical and electrochemical parameters due to alpha-irradiation are examined and thoroughly discussed. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Efficient alpha particle detection by CR-39 applying 50 Hz-HV electrochemical etching method

    International Nuclear Information System (INIS)

    Sohrabi, M.; Soltani, Z.

    2016-01-01

    Alpha particles can be detected by CR-39 by applying either chemical etching (CE), electrochemical etching (ECE), or combined pre-etching and ECE usually through a multi-step HF-HV ECE process at temperatures much higher than room temperature. By applying pre-etching, characteristics responses of fast-neutron-induced recoil tracks in CR-39 by HF-HV ECE versus KOH normality (N) have shown two high-sensitivity peaks around 5–6 and 15–16 N and a large-diameter peak with a minimum sensitivity around 10–11 N at 25°C. On the other hand, 50 Hz-HV ECE method recently advanced in our laboratory detects alpha particles with high efficiency and broad registration energy range with small ECE tracks in polycarbonate (PC) detectors. By taking advantage of the CR-39 sensitivity to alpha particles, efficacy of 50 Hz-HV ECE method and CR-39 exotic responses under different KOH normalities, detection characteristics of 0.8 MeV alpha particle tracks were studied in 500 μm CR-39 for different fluences, ECE duration and KOH normality. Alpha registration efficiency increased as ECE duration increased to 90 ± 2% after 6–8 h beyond which plateaus are reached. Alpha track density versus fluence is linear up to 10 6  tracks cm −2 . The efficiency and mean track diameter versus alpha fluence up to 10 6  alphas cm −2 decrease as the fluence increases. Background track density and minimum detection limit are linear functions of ECE duration and increase as normality increases. The CR-39 processed for the first time in this study by 50 Hz-HV ECE method proved to provide a simple, efficient and practical alpha detection method at room temperature. - Highlights: • Alpha particles of 0.8 MeV were detected in CR-39 by 50 Hz-HV ECE method. • Efficiency/track diameter was studied vs fluence and time for 3 KOH normality. • Background track density and minimum detection limit vs duration were studied. • A new simple, efficient and low-cost alpha detection method

  11. A fast neutron spectrometer based on an electrochemically etched CR-39 detector with degrader and front radiator

    International Nuclear Information System (INIS)

    Matiullah; Durrani, S.A.

    1987-01-01

    In addition to having promising applications for the development of a fast-neutron dosemeter, electrochemically etched (ECE) CR-39 detectors also offer the possibility of energy-selective fast-neutron detection. This property stems basically from the fact that, to produce 'sparkable' trails in the polymeric detector subjected to ECE, the charged particle resulting from a neutron interaction must fall within a definite 'energy window'. The lower and upper limits of proton energies that can yield ECE spots in CR-39 have been experimentally determined to be ∼ 50 keV and ∼ 2.2 MeV under our processing conditions. To accomplish our objective, we have developed a technique based on ECE spot-density measurements in CR-39 detectors placed in conjuction with judiciously chosen thicknesses of a polyethylene radiator and a lead degrader. The optimum thicknesses of the radiator and the degrader, for a given neutron energy, are determined by computer calculations. (author)

  12. The effects of pre-etching time on the characteristic responses of electrochemically etched CR-39 neutron dosimeters

    International Nuclear Information System (INIS)

    Sohrabi, M.; Khoshnoodi, M.

    1986-01-01

    The effects of pre-etching time (PET) or duration of etching of fast-neutron-induced-recoil tracks in CR-39 in 6N KOH at 60 0 C on electrochemical etching neutron characteristic responses; i.e. sensitivity and mean recoil track diameter (MRTD) versus KOH normality up to 18N are investigated in this paper. Six sets of responses for PETs of 0, 1, 2, 3, 4, and 5 hours were obtained by using our new multi-chamber ECE (MCECE) system which reduced total operation time to about 6% of the time usually required when single-chamber ECE systems are used. The sensitivity response for zero PET showed a broad plateau and a high sensitivity low-LET peak around 16N. By increasing PET, another peak was also developed around 5N leading to 'double-humped' responses with two maximums around 5N and 16N, and a minimum around 11N. On the other hand, the MRTD responses for all PETs studied showed the same general trend with maximums around 11N. In this paper, shape of tracks under different conditions are also investigated, new optimum conditions such as KOH concentrations of 5, 11, and 15N at 25 0 C, with or without pre-etching, are recommended for tracks of lower-LET recoils including possibly protons, and alpha particle tracks over a broad energy range, and the efficiency of the MCECE system is also demonstrated. (author)

  13. Gamma dosimetry with CR-39 etch track detector

    International Nuclear Information System (INIS)

    Matiullah; Dogar, A.H.; Ahmad, N.; Amin, M.; Kudo, Katsuhisa

    1999-01-01

    To preserve and improve the safety of food for commercial purposes, it is exposed to high gamma-ray doses. The gamma-ray doses used for this purpose range from 0.15 kGy to 50 kGy. At such high doses, the etching characteristics of CR-39 are severely affected. This property, therefore, can be used to develop a CR-39-based gamma dosimeter. In this context, systematic studies were carried out and the bulk etching rate was determined as a function of gamma-ray dose using different methods. (author)

  14. Etching characteristics of nuclear tracks in CR-39 plastics

    International Nuclear Information System (INIS)

    Tsuruta, Takao; Isobe, Ginko.

    1984-01-01

    In using CR-39 plastics for individual neutron dosimeters, changes of etching efficiency cause significant error in dose estimation. Etching efficiency is subject to a number of parameters. In this study the influences of the parameters were examined by measuring the diameters of etch-pits formed by alpha-particles and enlarged by aqueous solutions of 25-35% KOH at 55-65 0 C for 4 hr. It has been observed that diameter changes at the rate of 8.3%/ 0 C in temperature, 8.2%/wt% in concentration and -0.60%/day in time after preparation of etchant. The diameter is unaffected by the supplying of up to 280ml/l, of distilled water for evaporation of etchant or by increase up to 5g/l of CR-39 dissolved in etchant. The magnitude of possible error has been estimated by parameter as well as in general, so as to obtain suggestions for improving etching treatment. (author)

  15. Mass spectrometry analysis of etch products from CR-39 plastic irradiated by heavy ions

    Science.gov (United States)

    Kodaira, S.; Nanjo, D.; Kawashima, H.; Yasuda, N.; Konishi, T.; Kurano, M.; Kitamura, H.; Uchihori, Y.; Naka, S.; Ota, S.; Ideguchi, Y.; Hasebe, N.; Mori, Y.; Yamauchi, T.

    2012-09-01

    As a feasibility study, gas chromatography-mass spectrometry (GC-MS) and matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) have been applied to analyze etch products of CR-39 plastic (one of the most frequently used solid states nuclear track detector) for the understanding of track formation and etching mechanisms by heavy ion irradiation. The etch products of irradiated CR-39 dissolved in sodium hydroxide solution (NaOH) contain radiation-induced fragments. For the GC-MS analysis, we found peaks of diethylene glycol (DEG) and a small but a definitive peak of ethylene glycol (EG) in the etch products from CR-39 irradiated by 60 MeV N ion beams. The etch products of unirradiated CR-39 showed a clear peak of DEG, but no other significant peaks were found. DEG is known to be released from the CR-39 molecule as a fragment by alkaline hydrolysis reaction of the polymer. We postulate that EG was formed as a result of the breaking of the ether bond (C-O-C) of the DEG part of the CR-39 polymer by the irradiation. The mass distribution of polyallylalcohol was obtained from the etch products from irradiated and unirradiated CR-39 samples by MALDI-MS analysis. Polyallylalcohol, with the repeating mass interval of m/z = 58 Da (dalton) between m/z = 800 and 3500, was expected to be produced from CR-39 by alkaline hydrolysis. We used IAA as a matrix to assist the ionization of organic analyte in MALDI-MS analysis and found that peaks from IAA covered mass spectrum in the lower m/z region making difficult to identify CR-39 fragment peaks which were also be seen in the same region. The mass spectrometry analysis using GC-MS and MALDI-MS will be powerful tools to investigate the radiation-induced polymeric fragments and helping to understand the track formation mechanism in CR-39 by heavy ions.

  16. Bulk etching characteristics of CR-39 track detectors in hydroxide solutions

    International Nuclear Information System (INIS)

    Fonseca, E.S. da; Knoefel, T.M.J.; Tavares, O.A.P.

    1983-01-01

    A systematic study of the bulk etch rate of CR-39 track detectors in KOH and NaOH aqueous solutions is presented. A number of unirradiated and non-thermally treated CR-39 samples were chemically attacked in KOH and NaOH solutions of concentration and temperature in the range 2-10 N and 50-90 0 C, respectively. From measurements of the thickness of layers removed as a function of the etching time, the bulk etch rate υ β and the induction time T ο for surface removal were obtained for each etching condition. For both NaOH and KOH solution the activation energy of the process was derived as E = 0.76 ± 0.05 eV. It was observed that the induction time decreases both with increasing normality and temperature of the solution. (author) [pt

  17. The LLNL CR-39 personnel neutron dosimeter

    International Nuclear Information System (INIS)

    Hankins, D.E.; Homann, S.; Westermark, J.

    1987-01-01

    We developed a personnel neutron dosimetry system based on the electrochemical etching of CR-39 plastic at elevated temperatures. The doses obtained using this dosimeter system are more accurate than those obtained using other dosimetry systems, especially when varied neutron spectra are encountered. This CR-39 dosimetry system does not have the severe energy dependence that exists with albedo neutron dosimeters or the fading and reading problems encountered with NTA film. 3 refs., 4 figs

  18. Etching characteristics of a CR-39 track detector at room temperature in different etching solutions

    International Nuclear Information System (INIS)

    Dajko, G.

    1991-01-01

    Investigations were carried out to discover how the etching characteristics of CR-39 detectors change with varying conditions of the etching process. Measurements were made at room temperature in pure NaOH and KOH solutions; in different alcoholic KOH solutions (PEW solution, i.e. potassium hydroxide, ethyl alcohol, water); and in NaOH and KOH solutions containing different additives. The bulk etching rate of the detector (V B ) and the V (= V T /V B ) function, i.e. track to bulk etch rates ratio, for 6.1 MeV α-particles, were measured systematically. (author)

  19. Track etch parameters and annealing kinetics assessment of protons of low energy in CR-39 detector

    International Nuclear Information System (INIS)

    Jain, R.K.; Kumar, Ashok; Singh, B.K.

    2012-01-01

    Highlights: ► We calibrate CR-39 detector with very low energy protons. ► We establish linear relationship between track diameter and time/energy up to 200 keV. ► We determine activation energy of annealing using different models. ► We justify concept of single annealing activation energy in CR-39. - Abstract: In this paper threshold of the registration sensitivity of very low energy proton in CR-39 is investigated. Irradiation of CR-39 (poly-allyl-diglycol carbonate) was carried out with very low energy mono energetic protons of 20–60 keV from a mini proton accelerator. Nearly 10 4 /cm 2 fluence of protons was used. The variation of track diameter with etching time as well as proton energy response curve was carefully calibrated. The bulk and track etch rates were measured by using proton track diameters. Bulk etch rate was also measured by the thickness of removed surface layer. The thermal annealing of proton track at temperatures ranging from 100 to 200 °C in CR-39 was studied by several models. Activation energy of annealed CR-39 detectors was calculated by slope of track etch rate and temperature plot. The data of proton tracks of 200, 250 and 300 keV from 400 kV Van-de-Graaff accelerator was also used and compared with the track diameters of different energies of proton.

  20. Effect of certain production parameters and post-production treatments on the etching characteristics of CR-39 sheets

    Energy Technology Data Exchange (ETDEWEB)

    Somogyi, G.; Toth-Szilagyi, M.; Hunyadi, I.; Hafez, A.-F.

    1986-01-01

    There is a permanent need in producing track recording detectors of well defined behaviour from CR-39 monomer. Therefore, more studies on the role of production parameters determining the stability of main etching characteristics (bulk etch rate, Vsub(B);etch rate ratio, Vsub(T)/Vsub(B);opaqueness after longer etching periods) are highly required. In our studies we have examined different commercial CR-39 sheets (Homalite, Pershore, MA-ND) to compare their registration sensitivity to selected alpha and proton energies. In addition, we have investigated the main etching parameters of CR-39 sheets manufactured under different casting conditions varying the concentration of initiator and certain additives. Finally, the effect of some post-production treatments, annealing and storage in vacuum, on the Vsub(B) and Vsub(T)/Vsub(B) values is studied.

  1. Model calculations for electrochemically etched neutron detectors

    International Nuclear Information System (INIS)

    Pitt, E.; Scharmann, A.; Werner, B.

    1988-01-01

    Electrochemical etching has been established as a common method for visualisation of nuclear tracks in solid state nuclear track detectors. Usually the Mason equation, which describes the amplification of the electrical field strength at the track tip, is used to explain the treeing effect of electrochemical etching. The yield of neutron-induced tracks from electrochemically etched CR-39 track detectors was investigated with respect to the electrical parameters. A linear dependence on the response from the macroscopic field strength was measured which could not be explained by the Mason equation. It was found that the reality of a recoil proton track in the detector does not fit the boundary conditions which are necessary when the Mason equation is used. An alternative model was introduced to describe the track and detector geometry in the case of a neutron track detector. The field strength at the track tip was estimated with this model and compared with the experimental data, yielding good agreement. (author)

  2. Study of α-energy discrimination in CR-39 track etch detectors for use as a radon/thoron dosemeter

    International Nuclear Information System (INIS)

    Kandaiya, S.; Al-Najjar, S.A.R.; Piesch, E.

    1988-01-01

    The properties of CR 39 nuclear track detectors were evaluated for their α-energy discrimination up to 8.77 MeV using a combination of chemical-electrochemical track revealing techniques. Using three field strengths, α-energy discrimination by ECE track diameter and track density as a function of chemical pre-etching time were studied. α-energy spectra using different irradiation geometries were then evaluated using the optimum conditions and then compared with those obtained form other techniques. (author)

  3. Track profile and range studies of heavy and light ions in CR-39: effect of thermal pre-treatment on etching characteristics

    International Nuclear Information System (INIS)

    Al-Najjar, S.A.R.; Bull, R.K.; Durrani, S.A.

    1982-01-01

    Sheets of CR 39 have been irradiated with 20 Ne, 32 S, 40 Ar, 56 Fe and 63 Cu ions at normal incidence to the surface of the sheets and at normal incidence to the edges. The profiles of the etched tracks have been observed side-on and measurements made of the variation of V (the ratio of track to bulk etching velocities) along the tracks and of the fully etched range of the tracks. Heating the plastic at 100 0 C prior to etching produces zones within the plastic having different bulk etching rates Vsub(B). An outer zone of low Vsub(B) is followed by a zone of much higher Vsub(B). This allows tracks to be readily etched to very large diameters, comparable in size to the breakdown spots produced by electrochemical etching. (author)

  4. A quick method for maintaining the molarity of NaOH solution during continuous etching of CR-39

    International Nuclear Information System (INIS)

    Khan, E.U.; Husaini, S.N.; Malik, F.; Sajid, M.; Karim, S.; Qureshi, I.E.

    2002-01-01

    A series of experiments have been performed to investigate the physio-chemical changes that occurred in the 6 M NaOH solution after etching CR-39 (Pershore and Homalite) detectors, each for 3, 6, 9, 12 and 15 h. Various physical parameters like concentration, electrical conductivity (EC) and density of the solutions have been measured after each etching interval. Results have been discussed in the light of stoichiometrical equation for the interaction of CR-39 with NaOH. It is found that the concentration, EC and the density of the solution, in which CR-39 has been etched, increase linearly with respect to the etching time. The inter-relationship of EC-concentration and density-concentration suggest that the concentration of the etchant can be maintained at certain desired value by adjusting the corresponding value of EC or density, measured through non-destructive and quick methods

  5. Operational trials of single- and multi-element CR-39 dosemeters for the DIDO and PLUTO reactors at the Harwell Laboratory

    International Nuclear Information System (INIS)

    Gallacher, G.G.; Perks, C.A.

    1993-01-01

    Single- and multi-element CR-39 dosemeters, developed at the Harwell Laboratory, and a commercially available multi-element CR-39 dosemeter (obtained from Track Analysis Systems Ltd), were evaluated for their potential as neutron dosemeters for personnel working at Harwell Laboratory's research reactors. Owing to the angular dependence of the CR-39 (processed using electrochemical etching), the single-element dosemeter was found to be impractical. Consequently, a multi-element dosemeter was developed, which consisted of a cube of side 36 mm with CR-39 elements (also processed using electrochemical etching) attached to each of the sides. Although this dosemeter was technically suitable for this type of dosimetry, it was considered to be unacceptably bulky in personnel trials. The commercially available CR-39 dosemeter tested was much smaller (the CR-39 was only chemically etched) and this was considered to be acceptable as a personnel dosemeter. In addition, trials with personnel working at active handling glove boxes indicated that single-element dosemeters might be adequate, but further work would be needed to verify this. (author)

  6. Studies of biocompatibility of chemically etched CR-39 SSNTDs in view of their applications in alpha-particle radiobiological experiments

    International Nuclear Information System (INIS)

    Li, W.Y.; Chan, K.F.; Tse, A.K.W.; Fong, W.F.; Yu, K.N.

    2006-01-01

    Alpha-particle radiobiological experiments involve irradiating cells with alpha particles and require thin biocompatible materials which can record alpha-particle traversals as substrates for cell cultures. The biocompatibilities of chemically etched CR-39 solid-state nuclear track detectors (SSNTDs) using aqueous NaOH or NaOH/ehtanol are studied through the abundance and morphology of the cultured HeLa cells. The wetting properties of these etched CR-39 SSNTDs are also studied. The moderately hydrophobic CR-39 SSNTDs as well as the hydrophobic NaOH/ethanol-etched CR-39 SSNTDs are more biocompatible than the hydrophilic aqueous-NaOH-etched SSNTDs. Too small water contact angles, too large surface energy (γ s ) or the polar component γ s p do not favor the cell culture. On the other hand, the dispersive component γ s d of the surface energy and the ratio γ s p /γ s d do not seem to significantly affect the biocompatibility

  7. Spot formation of radiation particles by electrochemical etching

    International Nuclear Information System (INIS)

    Nozaki, Tetsuya

    1999-01-01

    An electrochemical etching (ECE) spot formation from the top of chemical etching (CE) spot was confirmed by a series of experiments. One of polycarbonate (Iupilon) could not make the spot, because ECE spot had grown up before the microscope confirming the CE spot. Clear CEC spots by α-ray and neutron were found on Harzlas and Baryotrak, both improvements of CR-39. Under the same etching conditions, the growth of ECE spot on Harzlas was more rapid than Baryotrak, but both spots were almost the same. All CE spot by α-ray produced the CEC spots, but a part of CE circle spot by neutron formed them. (S.Y.)

  8. Characterization of CR 39 nuclear track detector for use as a radon/thoron dosemeter

    International Nuclear Information System (INIS)

    Kandaiya, S.

    1988-02-01

    For the estimation of radon, thoron and their short-lived daughter products in air radon diffusion chambers with passive α-track etch detectors have been used. The report describes the properties of CR 39 track etch detectors in particular with respect to the spectrometric detection of α-particles in the energy range up to 8.77 MeV using chemical and a combination of chemical-electrochemical etching technique. In order to optimize the etching conditions for an α-energy discrimination in the energy range up to 8.77 MeV, the ECE track size diameter and the track density have been investigated as a function of the chemical pre-etching time using three electrical field strengths. In a mixed α-spectrum the contributions of various α-particles with energies between 4.6 to 8.77 MeV have been determined experimentally in CR 39 and compared with the spectral measurement using a surface barrier detector and the same irradiation geometry. Beside CR 39 detectors etched chemically and electrochemically, in addition surface barrier detectors and a Monte Carlo calculation have been used to evaluate the α-energy spectrum for thoron and its daughter products emitted by α-decays in the air volume and the plate-out of daughters at the inner surface on the diffusion chamber. (orig./HP) [de

  9. Energy-dependent etching-related impacts on CR-39 alpha detection efficiency for the Rn-222 and Rn-220 decay chains

    Science.gov (United States)

    Tan, Y.; Yuan, H.; Kearfott, K. J.

    2018-04-01

    CR-39 detectors are widely used to measure environmental levels of Rn-222, Rn-220 and their progeny. Prior research reported the CR-39 detection efficiency for alpha particles from Rn-222, Rn-220 and their progeny under a variety of etching conditions. This paper provides an explanation for interesting observations included in that work, namely that the critical incidence angle decreases with the increasing particle energy and the detection efficiency for 8.78 MeV alpha particles is zero. This paper explains these phenomena from a consideration of the interaction of alpha particles with the CR-39 detectors and the physics of etching dynamics. The proposed theory provides a rationale for an approach to optimizing the etching conditions of CR-39 detector for measuring Rn-222, Rn-220 and their progenies.

  10. Wide-range neutron dose determination with CR-39

    International Nuclear Information System (INIS)

    Arneja, A.R.; Waker, A.J.

    1995-01-01

    Optical density measurements of CR-30 irradiated with 252 Cf neutrons and chemically etched with 6.5 N KOH solution have been used to determine neutron absorbed doses between 0.1 and 10 Gy. Optimum etching conditions will depend upon the absorbed dose. Since it is not always possible to know the range of absorbed dose on a CR-39 dosemeter collected from personnel and area monitor stations in a criticality accident situation, a three-step two-hour chemical etch at 60 o C has been found to be appropriate. If after a total of six hours of chemical etching the optical density is found to be below 0.04 for 500 nm light (transmission > 90%) then further treatment in the form of electrochemical etching can be carried out to determine the lower absorbed dose. In this manner, absorbed doses below 0.1 Gy can be determined by counting tracks over a unit area. (author)

  11. Effects of high neutron doses and duration of the chemical etching on the optical properties of CR-39

    International Nuclear Information System (INIS)

    Sahoo, G.S.; Tripathy, S.P.; Paul, S.; Sharma, S.C.; Joshi, D.S.; Gupta, A.K.; Bandyopadhyay, T.

    2015-01-01

    Effects of the duration of chemical etching on the transmittance, absorbance and optical band gap width of the CR-39 (Polyallyl diglycol carbonate) detectors irradiated to high neutron doses (12.7, 22.1, 36.0 and 43.5 Sv) were studied. The neutrons were produced by bombardment of a thick Be target with 12 MeV protons of different fluences. The unirradiated and neutron-irradiated CR-39 detectors were subjected to a stepwise chemical etching at 1 h intervals. After each step, the transmission spectra of the detectors were recorded in the range from 200 to 900 nm, and the absorbances and optical band gap widths were determined. The effect of the etching on the light transmittance of unirradiated detectors was insignificant, whereas it was very significant in the case of the irradiated detectors. The dependence of the optical absorbance on the neutron dose is linear at short etching periods, but exponential at longer ones. The optical band gap narrows with increasing etching time. It is more significant for the irradiated dosimeters than for the unirradiated ones. The rate of the narrowing of the optical band gap with increasing neutron dose increases with increasing duration of the etching. - Highlights: • The variation of optical properties of CR-39 at very high neutron dose is analyzed. Etching process is found to play a crucial role for change in optical properties of neutron-irradiated CR-39. • The optical absorbance varies linearly at lower dose, at very high dose absorbance saturation occurs. The dose at which saturation absorbance is observed shifts towards lower neutron dose with increase in etching time. • The rate of decrease in optical band gap with respect to neutron dose is found to be more at higher etching durations

  12. The use of CH3OH additive to NaOH for etching alpha particle tracks in a CR-39 plastic nuclear track detector

    International Nuclear Information System (INIS)

    Ashry, A.H.; Abdalla, A.M.; Rammah, Y.S.; Eisa, M.; Ashraf, O.

    2014-01-01

    Fast detection of alpha particles in CR-39 detectors was investigated using a new chemical etchant. 252 Cf and 241 Am sources were used for irradiating samples of CR-39 SSNTDs with fission fragments and alpha particles in air at normal temperature and pressure. A series of experimental chemical etching are carried out using new etching solution (8 ml of 10N NaOH+1 ml CH 3 OH) at 60 °C to detect alpha particle in short time in CR-39 detectors. Suitable analyzing software has been used to analyze experimental data. From fission and alpha track diameters, the value of bulk etching rate is equal to 2.73 μm/h. Both the sensitivity and etching efficiency were found to vary with the amount of methanol in the etching solution. Pure NaOH was used as a control to compare with the result from etching in NaOH with different concentrations of CH 3 OH. The etching efficiency is determined and compared with conventional aqueous solution of 6.25N NaOH at 70 °C for etching time equals 5 h. In this study, the obtained etching efficiency shows a considerable agreement with the previous work. - Highlights: • The value of bulk etching rate is equal to 2.73 μm/h. • Fast detection of alpha particles in CR-39 detectors. • Samples of CR-39 have been irradiated with fission fragments. • Etching efficiency was determined

  13. Coherent light scattering by nuclear etched tracks in the PADC (a form of CR-39)

    Energy Technology Data Exchange (ETDEWEB)

    Groetz, J.E.; Chambaudet, A. [Universite de Franche-Comte, Besancon (France). Lab. de Microanalyses Nucleaires; Lacourt, A. [Laboratoire d`Optique P.M. Duffieux, UMR 6603 CNRS, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon Cedex (France)

    1998-08-01

    A new kind of measurement has been proposed to improve the reading of the solid state nuclear track detector CR-39. This method is based on coherent light scattering (He-Ne laser) by etched proton tracks, and is complementary to observation under an optical microscope and reading by optical density of the CR-39. The irradiated and chemically etched CR-39 sample is illuminated by a laser beam under a normal incidence angle. The light intensity diffracted by the tracks beyond the sample - defined with the bi-directional transmissive distribution functions - is measured with a photodiode. Thus, the bi-directional transmissive distribution functions depend on the characteristics of the irradiation, namely the track density, track sizes and orientations. We have performed a track light diffraction model calculation through the use of the Fraunhofer diffraction, Babinet`s principle and the spatial coherence and incoherence. We compared calculations and experimental results for the different shapes of tracks: conical, oblique and spherical-shaped. (orig.) 14 refs.

  14. Coherent light scattering by nuclear etched tracks in the PADC (a form of CR-39)

    International Nuclear Information System (INIS)

    Groetz, J.E.; Chambaudet, A.

    1998-01-01

    A new kind of measurement has been proposed to improve the reading of the solid state nuclear track detector CR-39. This method is based on coherent light scattering (He-Ne laser) by etched proton tracks, and is complementary to observation under an optical microscope and reading by optical density of the CR-39. The irradiated and chemically etched CR-39 sample is illuminated by a laser beam under a normal incidence angle. The light intensity diffracted by the tracks beyond the sample - defined with the bi-directional transmissive distribution functions - is measured with a photodiode. Thus, the bi-directional transmissive distribution functions depend on the characteristics of the irradiation, namely the track density, track sizes and orientations. We have performed a track light diffraction model calculation through the use of the Fraunhofer diffraction, Babinet's principle and the spatial coherence and incoherence. We compared calculations and experimental results for the different shapes of tracks: conical, oblique and spherical-shaped. (orig.)

  15. The influence of chemical etching time on efficiency of radon detection using CR-39

    Energy Technology Data Exchange (ETDEWEB)

    Reway, Adriana P.; Kappke, Jaqueline; Narloch, Danielle C., E-mail: adrireway@hotmail.com, E-mail: jaquelinekappke@gmail.com, E-mail: daninarloch@hotmail.com [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Departamento Academico de Fisica; Del Claro, Flavia; Paschuk, Sergei A., E-mail: flaviadelclaro@gmail.com, E-mail: spaschuk@gmail.com [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Programa de Pos-Graduaca em Engenharia Eletrica e Informatica Industrial; Correa, Janine N., E-mail: janine_nicolosi@hotmail.com [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Departamento Academico de Construcao Civil

    2015-07-01

    Natural radiation is the principal source of human exposure to ionizing radiation. Radon is noble radioactive gas that emanates from the soil and rocks entering the atmosphere of dwellings where it could be accumulated. The inhalation of {sup 222}Rn represents a significant health risk. Solid-State Nuclear Track Detectors (SSNTD) represents an efficient method for alpha particle detection and measurements of the activity concentration of {sup 222}Rn. The aim of present work was to study the etching time impact on CR-39 efficiency in radon activity measurements. The investigation was performed using 80 CR-39 detectors, which were exposed to a source of radon. After the exposition, alpha particle tracks development was achieved by chemical etching using 6.25M NaOH solution and ethanol (2%) at 70°C. Etching alpha particle tracks were identified and counted manually using the optical microscope with magnification of 100x and glass overlay mask. The etching time ranged from 7 to 14 hours. The results show that there is an increase in the number of visible tracks with increased etching time. The number of traces obtained for 7 hours and 8 hours of revelation was 1430 +/- 90 and 2090 +/- 160, respectively. However, for etching time of 13 and 14 hours was not observed statistical increase in the number of visible tracks. The number of tracks in this situation was 3630 +/- 180 and 3870 +/- 160 to 13 and 14 hours etching. Thus, for assumed etching parameters, the etching optimal time was observed 14 hours. (author)

  16. The influence of chemical etching time on efficiency of radon detection using CR-39

    International Nuclear Information System (INIS)

    Reway, Adriana P.; Kappke, Jaqueline; Narloch, Danielle C.; Del Claro, Flavia; Paschuk, Sergei A.; Correa, Janine N.

    2015-01-01

    Natural radiation is the principal source of human exposure to ionizing radiation. Radon is noble radioactive gas that emanates from the soil and rocks entering the atmosphere of dwellings where it could be accumulated. The inhalation of 222 Rn represents a significant health risk. Solid-State Nuclear Track Detectors (SSNTD) represents an efficient method for alpha particle detection and measurements of the activity concentration of 222 Rn. The aim of present work was to study the etching time impact on CR-39 efficiency in radon activity measurements. The investigation was performed using 80 CR-39 detectors, which were exposed to a source of radon. After the exposition, alpha particle tracks development was achieved by chemical etching using 6.25M NaOH solution and ethanol (2%) at 70°C. Etching alpha particle tracks were identified and counted manually using the optical microscope with magnification of 100x and glass overlay mask. The etching time ranged from 7 to 14 hours. The results show that there is an increase in the number of visible tracks with increased etching time. The number of traces obtained for 7 hours and 8 hours of revelation was 1430 +/- 90 and 2090 +/- 160, respectively. However, for etching time of 13 and 14 hours was not observed statistical increase in the number of visible tracks. The number of tracks in this situation was 3630 +/- 180 and 3870 +/- 160 to 13 and 14 hours etching. Thus, for assumed etching parameters, the etching optimal time was observed 14 hours. (author)

  17. Fast neutron personnel dosimetry by CR-39 plastics a new electrochemical etching procedure

    International Nuclear Information System (INIS)

    Djeffal, S.

    1984-07-01

    In the first part of this work a brief description of solid state nuclear track detectors, the principles of track registration and the different reading techniques are given. In the experimental part of the present work we systematically analysed different etching procedures and set a new electrochemical etching method, which enables us to develop a new fast neutron dosimeter. This fast neutron dosimeter makes possible the measurement of low neutron doses in the energy range from 10 Kev to 20 Mev with a reasonably flat energy response. These new developments are very attractive in personnel neutron dosimetry where nuclear emulsions are still used despite their insensitivity to neutron energies down to 500 Kev (i.e. the energy range one often encounters around nuclear facilities)

  18. The effect of ArF laser irradiation (193 nm) on the photodegradation and etching properties of alpha-irradiated CR-39 detectors

    Energy Technology Data Exchange (ETDEWEB)

    Shakeri Jooybari, B. [Department of Energy Engineering and Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Nuclear Science and Technology Research Institute (NSRT), Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Ghergherehchi, M. [College of Information and Technology/ school of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon (Korea, Republic of); Afarideh, H., E-mail: hafarideh@aut.ac.ir [Department of Energy Engineering and Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Lamehi-Rachti, M. [Nuclear Science and Technology Research Institute (NSRT), Tehran, Islamic Republic of Iran (Iran, Islamic Republic of)

    2015-01-01

    The effects of ArF laser irradiation (λ=193nm) at various fluences (energy dose or energy density) on the etching properties of pre-exposed (laser + alpha) CR-39 detectors were studied. First, UV–Vis and Fourier transform infrared (FTIR) spectra were acquired for non-laser-irradiated and laser-irradiated samples to detect the influence of the ArF laser on the chemical modification of the CR-39. Changes observed in the spectra indicated that the predominant process that occurred upon ArF laser irradiation was a bond-scission process. Thereafter, the mean track and bulk etching parameters were experimentally measured in ArF-laser-irradiated CR-39 detectors exposed to an alpha source ({sup 241}Am, E = 5.49 MeV). Inhomogeneous regions in the laser-irradiated side of the CR-39 demonstrated a variable etching rate on only the front side of the CR-39 detector. New equations are also presented for the average bulk etching rate for these inhomogeneous regions (front side). The mean bulk and track etching rates and the mean track dimensions increased in a fluence range of 0–37.03 mJ/cm{sup 2} because of photodegradation and the scission of chemical bonds, which are the predominant processes in this range. When the fluence was increased from 37.03 to 123.45 mJ/cm{sup 2}, the bulk and track etching rates and the track dimensions slowly decreased because of the formation of cross-linked structures on the CR-39 surface. The behavior of the bulk and track etching rates and the track dimensions appears to be proportional to the dose absorbed on the detector surface. It was observed that as the etching time was increased, the bulk and track etching rates and the track dimensions of the laser-irradiated samples decreased because of the shallow penetration depth of the 193 nm laser and the reduction in the oxygen penetration depth.

  19. Effect of various etching conditions on the response of Cr-39 plastic track detector applied for radon dosimetry in environment

    International Nuclear Information System (INIS)

    Maged, A.F.; Ashraf, F.A.

    1997-01-01

    A solid state nuclear track detector Cr-39 has been used for measuring the radon concentration in the soil air and indoor concentration. The bulk etch rate, C B of Cr-39 has been measured in various concentrations of NaOH in the range (6-8 mole) at temperature 70 degree C. In addition, the track etch rate, V T , and the ratio V = V T /V B , of alpha particles emitted from radon gas exists in nature have been measured in a similar range of etching conditions. This study shows that 8 M NaOH at 70 degree C represent the optimum etching conditions for Cr-39, with the range of the present study. The equilibrium factor and gamma-dose equivalent were calculated by using the track densities of open and filtered solid state nuclear track detectors

  20. Measurement of the variable track-etch rate of hydrogen, carbon and oxygen Ions in CR-39

    International Nuclear Information System (INIS)

    Lengar, I.; Skvarc, J.; Ilic, R.

    2003-01-01

    The ratio of the track-etch rate to the bulk-etch rate for hydrogen, carbon and oxygen ions was studied for the CR-39 detector with addition of dioctylphthalate. The response was reconstructed from etch-pit growth curves obtained by the multi-step etching technique. A theoretical analysis of the correctness of the method due to the 'missing track segment' is assessed and utilisation of the results obtained for the calibration of fast neutron dosimetry is discussed. (author)

  1. The etching property of the surface of CR-39 and the track core radius of fission fragment

    CERN Document Server

    Mineyama, D; Yamauchi, T; Oda, K; El-Rahman, A

    2002-01-01

    The etch pits of fission fragments in CR-39 detector have been observed carefully using an atomic force microscope (AFM) after extremely short chemical etching in stirred 6N KOH solution kept at 70degC. It was found that there existed a thin layer where the bulk etch rate is relativity from large the etch-pit growth curve for the etching duration between 10 and 1800 seconds. The track core radius of fission fragment was evaluated to be about 6 nm from the extrapolation of the growth curve in a thinner region. (author)

  2. A CR-39 track dosemeter for routine individual neutron monitoring

    International Nuclear Information System (INIS)

    Luszik-Bhadra, M.; Alberts, W.G.; Dietz, E.; Guldbakke, S.; Matzke, M.; d'Errico, F.

    1994-01-01

    A personal neutron dosemeter for routine individual monitoring is proposed. It is based on a CR-39 track detector covered on three separate areas by converters with different boron contents and inserted into a commercial TLD albedo dosemeter capsule. The dose readings from three areas of the electrochemically etched CR-39 detector are combined to yield a dose equivalent response which is almost independent of the incident neutron energy in the range from thermal neutrons up to 20 MeV. In addition, the dose contributions of thermal, intermediate and fast neutrons can be determined separately. Unlike the TLD albedo dosemeter, which in general requires prior in-field calibration and whose use is then restricted to that field, this dosemeter can be used in neutron fields without any knowledge of the spectral distribution with the same calibration factor. The angular dependence of the dosemeter's response has been measured and compared with that of the directional dose equivalent H'(10). The lower limit of detection is 0.15 mSv. It is possible to obtain an independent, second dose reading from the same Cr-39 detector for neutron energies above 100 keV. The dosemeter has also been successfully tested for use in accident dosimetry applying chemical etching and an optical density reading of the CR-39 detector. (author)

  3. Development and application of the electrochemical etching technique

    International Nuclear Information System (INIS)

    Sanders, M.E.

    1984-07-01

    This report documents the advances achieved in the development and application of several etched damage track plastic dosimeters that can be used to measure dose-equivalent from neutrons with energies from thermal to 20 MeV. The project was initiated with the design of a rem-responding dosimeter that measured fast (> 1 MeV) neutron dose-equivalent as a function of the damage track density directly induced within the volume of polycarbonate foils amplified by electrochemical etching. Stillwagon (1978) adapted electrochemical etching of polycarbonate foils (ECEPF) to alpha dosimetry and used the technique to determine Pu-239 uptake in human bone. Su (1979) extended the usefulness of the ECEPF neutron dosimetry technique to encompass thermal neutron dose measurement. The thermal neutron dosimeter was composed of an external radiator tablet made of 7 LiF in contact with a polycarbonate foil and utilized the thermal neutron-induced 6 Li(n, α) 3 H reaction to give a dose-equivalent response as a function of alpha track density registered in the detector foil. An intermediate (1 eV-1 MeV) neutron dosimeter was developed and has been shown to give an approximately dose-equivalent response to neutrons with energies from 1 eV to 17 MeV. The intermediate neutron dosimeter consists of 6 LiF-Teflon/CR-39 Polymer foil assembly which is enclosed by a (Cd + In) neutron filter. The neutron dose-equivalent is measured as a variable function of the damage track density registered in the CR-39 detector foil due to alpha particles from the 1/v dependent 6 Li(n, α) 3 H reaction, recoil H, C, O nuclei from neutron-induced elastic scattering within the foil volume, and protons from the 6 Li(n, p) reaction for neutron energies above 2 MeV. 46 figs., 6 tabs

  4. Interpretation of Mason's equation in terms of measurable electrochemical-etching parameters governing the dielectric breakdown phenomenon

    International Nuclear Information System (INIS)

    Al-Najjar, S.A.R.; Durrani, S.A.

    1986-01-01

    A new interpretation of Mason's equation, as applicable to the electrochemical etching (ECE) of tracks in polymers, is presented in terms of physically meaningful track-etching parameters. The values of these parameters have been experimentally obtained by irradiating CR-39 foils with heavy ions ( 238 U and 129 Xe) and α-particles of various energies, and applying chemical pre-etching (CPE), followed by ECE in steps, with increasing electric field until the 'treeing' breakdown is initiated. A value of 1.19 MV cm -1 is obtained for the intrinsic electrical breakdown stress of CR-39. It is found that the track radius r used in Mason's equation is related to the radius rsub(Θ) of a sphere, inscribed within the etch cone, whose lowest point is at a fixed distance lsub(o) above the cone tip, with lsub(o) ≅ 1.75 μm for α-particle tracks of energies 2-5.5 MeV, such that r = 0.43 + rsub(Θ) (in μm). (author)

  5. High energy charged particle registration in CR-39 polycarbonated detector

    International Nuclear Information System (INIS)

    Abdel-Wahab, M.S.; El Enany, N.; El Fiki, S.; Eissa, H.M.; El-Adl, E.H.; El-Feky, M.A.

    1991-01-01

    Track etch rate characteristics of CR-39 plastic detector exposed to 28 Si ions of 670 MeV energy have been investigated. Experimental results were obtained in terms of frequency distribution of the track diameter, track density and bulk etching rate. A dependence of the mean track diameter on energy was found. The application of the radiation effect of heavy ions on CR-39 in the field of radiation detection and dosimetry are discussed. Results indicated that it is possible to produce etchable tracks of 28 Si in this energy range in CR-39. We also report the etching characteristics of these tracks in the CR-39 detector. (orig.) [de

  6. A study on alpha particles range in Cr-39

    International Nuclear Information System (INIS)

    Ibrahim, Z.A.; Talaat, T.M.; Abdel-Aziz, Kh.M.A.; El-Asser, M.R.

    2000-01-01

    Cr-39 plastic nuclear track detector has been used in range determination of alpha particles. A set of experiments was carried out for studying alpha energy and track diameter relationships. This work was done under the optimum conditions of Cr-39 etching in 6.25 N NaOH at 70 degree C for various etching times. Determination of alpha range in Cr-39 recorders was studied at different energy values using the over etched track profile technique. Data are discussed within the framework of track formation theory in plastic foils, comparison between experimental and theoretical values of alpha range is included

  7. Interrelated temperature dependence of bulk etch rate and track length saturation time in CR-39 detector

    International Nuclear Information System (INIS)

    Azooz, A.A.; Al-Jubbori, M.A.

    2013-01-01

    Highlights: • New empirical parameterization of CR-39 bulk etch rate. • Bulk etch rates measurements using two different methods give consistent results. • Temperature independence of track saturation length. • Two empirical relation between bulk etch rate and temperature are suggested. • Simple inverse relation between bulk etch rate and track saturation time. -- Abstract: Experimental measurements of the etching solution temperature dependence of bulk etch rate using two independent methods revealed a few interesting properties. It is found that while the track saturation length is independent of etching temperature, the etching time needed to reach saturation is strongly temperature-dependent. It is demonstrated that there is systematic simple inverse relation between track saturation time, and etching solution temperature. In addition, and although, the relation between the bulk etch rate and etching solution temperature can be reasonably described by a modified form of the Arrhenius equation, better fits can be obtained by another equation suggested in this work

  8. Optimization of microwave-induced chemical etching for rapid development of neutron-induced recoil tracks in CR-39 detectors

    International Nuclear Information System (INIS)

    Sahoo, G.S.; Tripathy, S.P.; Bandyopadhyay, T.

    2014-01-01

    A systematic investigation is carried out to optimize the recently established microwave-induced chemical etching (MICE) parameters for rapid development of neutron-induced recoil tracks in CR-39 detectors. Several combinations of all available microwave powers with different etching durations were analysed to determine the most suitable etching condition. The etching duration was found to reduce with increasing microwave power and the tracks were observed at about 18, 15, 12, and 6 min for 300, 450, 600 and 900 W of microwave powers respectively compared to a few hours in chemical etching (CE) method. However, for complete development of tracks the etching duration of 30, 40, 50 and 60 min were found to be suitable for the microwave powers of 900, 600, 450 and 300 W, respectively. Temperature profiles of the etchant for all the available microwave powers at different etching durations were generated to regulate the etching process in a controlled manner. The bulk etch rates at different microwave powers were determined by 2 methods, viz., gravimetric and removed thickness methods. A logarithmic expression was used to fit the variation of bulk etch rate with microwave power. Neutron detection efficiencies were obtained for all the cases and the results on track parameters obtained with MICE technique were compared with those obtained from another detector processed with chemical etching. - Highlights: • Microwave-induced chemical etching method is optimized for rapid development of recoil tracks due to neutrons in CR-39 detector. • Several combinations of microwave powers and etching durations are investigated to standardize the suitable etching condition. • Bulk-etch rates are determined for all microwave powers by two different methods, viz. gravimetric and removed thickness method. • The method is found to be simple, effective and much faster compared to conventional chemical etching

  9. Activation energy of etching for CR-39 as a function of linear energy transfer of the incident particles

    CERN Document Server

    Awad, E M

    1999-01-01

    In this work, we have studied the effect of the radiation damage caused by the incident particles on the activation energy of etching for CR-39 samples. The damage produced by the incident particle is expressed in terms of the linear energy transfer (LET). CR-39 samples from American Acrylic were irradiated to three different LET particles. These are N (LET sub 2 sub 0 sub 0 = 20 KeV/mu m) as a light particle, Fe (LET sub 2 sub 0 sub 0 = 110 KeV/mu m) as a medium particle and fission fragments (ff) from a sup 2 sup 5 sup 2 Cf source as heavy particles. In general the bulk etch rate was calculated using the weight difference method and the track etch rate was determined using the track geometry at various temperatures (50-90 deg. C) and concentrations (4-9 N) of the NaOH etchant. The average activation energy E sub b related to the bulk etch rate v sub b was calculated from 1n v sub b vs. 1/T. The average activation energy E sub t related to the track etch rate v sub t was estimated from 1n v sub t vs. 1/T. It...

  10. Evolution of etched nuclear track profiles of alpha particles in CR-39 by atomic force microscopy

    International Nuclear Information System (INIS)

    Félix-Bautista, R.; Hernández-Hernández, C.; Zendejas-Leal, B.E.; Fragoso, R.; Golzarri, J.I.; Vázquez-López, C.; Espinosa, G.

    2013-01-01

    A series of atomic force microscopy (AFM) images of etched nuclear tracks has been obtained and used to calculate the nuclear track registration sensitivity parameter V(x) = Vt(x)/Vb. Due to the AFM limitations the samples were irradiated normally to the surface, and with energies attenuated in order to include the Bragg peak region in the AFM piezo-scanner z movement range. The simulation of the track profile evolution was then obtained. The different stages of etched nuclear track profiles were rendered. - Highlights: ► Using AFM we reach that Bragg peak region of etched tracks in CR-39. ► The etched track sensitivity V was calculated by data obtained by AFM. ► The evolucion of etched nuclear tracks was simulated by data achieved by AFM

  11. Track sensitivity and the surface roughness measurements of CR-39 with atomic force microscope

    CERN Document Server

    Yasuda, N; Amemiya, K; Takahashi, H; Kyan, A; Ogura, K

    1999-01-01

    Atomic Force Microscope (AFM) has been applied to evaluate the surface roughness and the track sensitivity of CR-39 track detector. We experimentally confirmed the inverse correlation between the track sensitivity and the roughness of the detector surface after etching. The surface of CR-39 (CR-39 doped with antioxidant (HARZLAS (TD-1)) and copolymer of CR-39/NIPAAm (TNF-1)) with high sensitivity becomes rough by the etching, while the pure CR-39 (BARYOTRAK) with low sensitivity keeps its original surface clarity even for the long etching.

  12. Design and development of wide energy neutron REM equivalent spectrometer-dosimeters based on polycarbonates and Cr-39

    International Nuclear Information System (INIS)

    Faermann, S.

    1985-03-01

    This work describes a system composed of a Rem response personnel neutron dosemeter, based on boron radiators and a polycarbonate track detector, for monitoring dose equivalents in the energy range 1 eV to 14 MeV, an electrochemical etching system for revealing damage sites in solid state track etch detectors, a reader for magnifying the etched pits and a microprocessor for evaluating the dose equivalents and their uncertainties. The performance and directional dependence of the dosemeter when exposed to monoenergetic and polyenergetic neutron fields in the epithermal and fast energy regions are discussed. Saturation effects in polycarbonate foils are presented and a comparison is made between the response of polycarbonate and CR-39 foils, used as passive detectors in the dosemeter. A new passive miniature fast neutron spectrometer-dosimeter is also described. The device is based on the detection of proton tracks by electrochemical etching of CR-39 foils covered with thin polyethylene layers of different thicknesses. By means of this device it is possible to assess the fast neutron energy spectrum in 10 energy intervals in the energy range 0.5-15 MeV. Dose equivalents can be determined in the dose equivalent range 20 mRem to 8 Rem, approximately (author)

  13. A study of the molecular structure in CR-39

    International Nuclear Information System (INIS)

    Stejny, J.; Portwood, T.

    1986-01-01

    A technique is presented for examining the molecular structure of CR-39 by analysis of the etch products from hydrolysis of the polymer network. The CR-39 network consists of polyallyl chains jointed by diethyleneglycol dicarbonate links. The etching cuts the carbonate links and liberates the polyallyl chains which makes them amenable to common analytical methods. Gel Permeation Chromatography was used to characterize the chain lengths and their distribution. It was found that the average length is rather short and that it decreases with increasing concentration of the initiator. This technique has been also used to identify the radiation sensitive link in the CR-39 network. It was found that the length of polyallyl chain is not changed in 60 Co γ-irradiated plastic while the etch rate significantly increases. This shows that the polyallyl chains are relatively inert and not responsible for the radiation sensitivity of CR-39 and that it is the diethyleneglycol dicarbonate links which are damaged by radiation. (author)

  14. Dose-rate effects on the bulk etch-rate of CR-39 track detector exposed to low-LET radiations

    CERN Document Server

    Yamauchi, T; Oda, K; Ikeda, T; Honda, Y; Tagawa, S

    1999-01-01

    The effect of gamma-rays and pulsed electrons has been investigated on the bulk etch rate of CR-39 detector at doses up to 100 kGy under various dose-rate between 0.0044 and 35.0 Gy/s. The bulk etch rate increased exponentially with the dose at every examined dose-rates. It was reveled to be strongly depend on the dose-rate: the bulk etch rate was decreased with increasing dose-rate at the same total dose. A primitive model was proposed to explain the dose-rate effect in which oxygen dissolved was assumed to dominate the damage formation process.

  15. Characterization of plastic nuclear track detectors on solid state, CR-39 and LR-115 and its possibilities application on thermal and fast neutron dosimetry

    International Nuclear Information System (INIS)

    Vallejo Delgado, L.R.

    1989-01-01

    This work is an study about the use feasibility of plastic nuclear track detectors, LR 115, II-B (of Eastmann Kodak Co) and CR-39 (of American Acrylics and Plastics), for thermal and fast neutron dosimetry, respectively. The LR-115 with converter (n, alpha) was exposed to thermal neutrons with energy of 0,046 e V, proceeding from nuclear reactor RECH-1 of Nuclear Energy Chilean Commission. The irradiated films were submited to a chemical etching with NaOH, plus a washing and brushing. The CR-39 with polyethylene irradiator, was exposed to fast neutrons proceeding of calibrated sources of Am-Se. The irradiated plates were submited to a chemical pre-etching with KOH and a electrochemical post-etching. (author)

  16. Fast neutron dosimetry using CR-39 track detectors with polyethylene as radiator

    International Nuclear Information System (INIS)

    Castillo, F.; Espinosa, G.; Golzarri, J.I.; Osorio, D.; Rangel, J.; Reyes, P.G.; Herrera, J.J.E.

    2013-01-01

    The chemical etching parameters (etching time, temperature, normality of etchant, etc.) for the use of CR-39 (allyl diglycol carbonate – Lantrack ® ) as a fast neutron dosimeter have been optimized. The CR-39 chips, placed under a 1.5 mm polyethylene radiator, were exposed for calibration to an 241 Am-Be source at different time intervals for a given neutron fluence. After several chemical etching processes of the detectors with different conditions, the optimum characteristics for the chemical etching were found at 6N KOH solution, 60 ± 1 °C, for 12 h. An accurate relationship between the dose and fluence calculations was obtained as a function of the track density. - Highlights: ► Optimum etching time for fast neutron irradiated CR-39 track detectors is found. ► Relationship between dose and fluence obtained as a function of the track density. ► Results are consistent with those reported elsewhere, and extend the dose range

  17. Study etching characteristics of a track detector CR-39 with ultraviolet laser irradiation

    International Nuclear Information System (INIS)

    Dwaikat, Nidal; Iida, Toshiyuki; Sato, Fuminobu; Kato, Yushi; Ishikawa, Ippei; Kada, Wataru; Kishi, Atsuya; Sakai, Makoto; Ihara, Yohei

    2007-01-01

    The effect of pulsed ultraviolet Indium-doped Yttrium Aluminum Garnet (UV-In:YAG) laser of λ=266 nm, pulse energy 42 mJ/pulse at repetition rate10 Hz on the etching characteristics of Japanese CR-39 was studied at various energy intensities. Fifteen detectors were divided into two sets, each of seven samples and one sample was kept as a reference.The first set (post-exposed) was first exposed to alpha radiation with close contact to 241 Am and then treated in air with laser in the energy intensity range from 40 to160 J/cm 2 , 20 J/cm 2 in step. The second set (pre-exposed) was irradiated in reverse process (laser+alpha) with the same sources as the first set and under the same condition. The laser energy intensities ranged between 20 and 140 J/cm 2 , 20 J/cm 2 in step. For post-exposed samples (alpha+laser) bulk etch rate decreases up to 60 J/cm 2 and increases thereafter, while for pre-exposed samples (laser+alpha) the bulk etch rate oscillates without showing any precise periodicity. The bulk etch rate for both sets was found to be the same at 60≤energy intensity≤80 J/cm 2 and this may indicate that the same structural changes have happened. The track etch rate was found to be equal to the bulk etch rate for both sets, so the sensitivity is constant. In both sets several changes on the detector surfaces: tracks of different sizes and shapes and high density within the laser spot were observed. Out of the laser spot, the tracks become larger and lower density, indicating cross-linking and scission have happened, simultaneously, on the same surface as a result of UV-laser irradiation

  18. Characterization of saturation of CR-39 detector at high alpha-particle fluence

    Directory of Open Access Journals (Sweden)

    M. El Ghazaly

    2018-04-01

    Full Text Available The occurrence of saturation in the CR-39 detector reduces and limits its detection dynamic range; nevertheless, this range could be extended using spectroscopic techniques and by measuring the net bulk rate of the saturated CR-39 detector surface. CR-39 detectors were irradiated by 1.5 MeV high alpha-particle fluence varying from 0.06 × 108 to 7.36 × 108 alphas/cm2 from Am-241 source; thereafter, they were etched in a 6.25N NaOH solution at a temperature of 70°C for different durations. Net bulk etch rate measurement of the 1.5 MeV alpha-irradiated CR-39 detector surface revealed that rate increases with increasing etching time and reaches its maximum value at the end of the alpha-particle range. It is also correlated with the alpha-particle fluence. The measurements of UV–Visible (UV–Vis absorbance at 500 and 600 nm reveal that the absorbance is linearly correlated with the fluence of alpha particles at the etching times of 2 and 4 hour. For extended etching times of 6, 10, and 14.5 hour, the absorbance is saturated for fluence values of 4.05 × 108, 5.30 × 108, and 7.36 × 108 alphas/cm2. These new methods pave the way to extend the dynamic range of polymer-based solid state nuclear track detectors (SSNTDs in measurement of high fluence of heavy ions as well as in radiation dosimetry. Keywords: Alpha Particle, Bulk Etch Rate, CR-39 Detector, Saturated Regime, UV–Vis Spectroscopy

  19. Neutron detection using CR-39 and Atomic Force Microscopy (AFM)

    International Nuclear Information System (INIS)

    Vazquez L, C.; Fragoso, R.; Felix, R.; Golzarri, J.I.; Espinosa, G.; Castillo, F.

    2007-01-01

    AFM has been applied in many CR-39 track formation analyses. In this paper, the use of AFM in the neutron detection and analysis of the track formation is reported. The irradiation was made with an 1.5 GBq (0.5 Ci) 241 Am-Be neutron source, with and without a polyethylene radiator. The surface analysis was made to the CR-39 fresh material without irradiation, after the irradiation, and after a very short etching time. The results show important differences between the irradiation, with and without polyethylene radiator, and the latent tracks of the neutron in the CR-39 polycarbonate. The development of track formation after very short etching time and pits characterization were measured too using the AFM facilities. (Author)

  20. Cr-39 fast neutron dosemeter based on A (n, α) converter

    International Nuclear Information System (INIS)

    Widayati, S.; Budiantari, T.

    1998-01-01

    The aim of this experiment is to obtained the response of Cr-39 as fast neutron dosemeter based on an (n, α) converter. Cr-39 was irradiated to AmBe fast neutron flux from 0.10 mSv to 2.5 mSv. Cr-39 processed by chemical etching with NaOH 20 % at temperature of 60 oC in six hours. The results of experiment showed that the response of Cr-39 based on an (n, α) converter is 6 times bigger than the response of Cr-39 without (n, α) converter. (author)

  1. A comparison of the neutron response of CR-39 made by different manufacturers

    International Nuclear Information System (INIS)

    Ipe, N.E.; Liu, J.C.; Buddemeier, B.R.; Miles, C.J.; Yoder, R.C.

    1991-09-01

    CR-39 was obtained from American Acrylics and Plastics, Inc. (A.A), N. E. Technology, Ltd. (N.E), and Tech/Ops Landauer, Inc. (LT). The dosemeters were exposed to radioisotopic neutron sources at SLAC, and moderated 252 Cf at ORNL. The A.A. and N.E. dosemeters were electrochemically etched (pre-etch in 6.5 N KOH at 60 degrees C for 1 hour and 45 minutes, a 5 hour etch at 3000 V and 60 Hz, a 23 minute blow-up step at 2 kHz and a post-etch for 15 minutes). Track densities were determined with the Homann Track Size Image Analyzer. The LT dosemeters were chemically etched in 5.5 N NaOH at 70 degrees C for 15.5 hours. Some A.A., N.E., and LT dosemeters were etched in 6.25 N NaOH at 70 degrees C for 6 hours. A pre-etch step in 60% methanol and 40% NaOH at 70 degrees C for 1 hour was added for some N.E. dosemeters. The results of these studies are reported in this paper. 3 refs., 2 figs., 2 tabs

  2. Study of the pore-opening process of latent tracks of light low-energetic ions in CR-39 by means of electrolytic etching

    International Nuclear Information System (INIS)

    Oganesyan, V.R.

    2005-01-01

    In this thesis the irradiation of 10-μm thick CR-39 foils with 5.5-7 MeV protons and of 22-400 μm thick CR-39 foils with 4.85-28 MeV α-particles with subsequent determination of the etching velocities is described. By means of scanning electron microscopy (SEM) the pore shape after irradiation was determined. From the analysis of the track profiles by means of SEM the track-nucleus diameter for 28 MeV α particles was determined to 1.4 nm. (HSI)

  3. Beam profile measurement with CR-39 track detector for low-energy ions

    CERN Document Server

    Sato, F; Tanaka, T; Iida, T; Yamauchi, T; Oda, K

    1999-01-01

    A CR-39 track detector was successfully used to measure the outline of thin low-energy ion beams. After the etching, the surface of the detector was examined with an observation system composed of a Normarski microscope, a CCD camera and a digital image processing computer. Beam images obtained with the system were in good agreement on the outline of the beam formed with a beam aperture. Also, the resolving power in the beam outline measurement was roughly explained from the consideration of the ion range and the etch-pit growth in the chemical etching for the CR-39 detector.

  4. Study of the characteristics of ionizing particles record of CR-39 track detectors

    International Nuclear Information System (INIS)

    Brandao, Luis Eduardo Barreira

    1983-01-01

    The bulk and track etching proprieties of a new Solid State Nuclear Track Detector CR-39 were investigated under different etching conditions. The discussion is based on results obtained using aqueous solutions of KOH with addition of alcoholic solvent to aqueous solutions. It was found that track registration sensitivity can be dramatically changed by using the proper chemical treatment. A method to enlarge and dye etch tracks to be viewed by simple projection on a screen is discussed. The applications of CR-39 in neutron fluence measurements are shown. Graphs are presented of the densities of the registered traces by the detector as a function of etch time both for samples with and without a polycarbonate radiator. (author)

  5. Alpha-particle response characteristics of CR-39

    International Nuclear Information System (INIS)

    Abou El-Khier, A.A.; Gaber, M.; El-Khatib, A.M.; Fawzy, M.A.

    1987-01-01

    The form of the response curve of the polycarbonate CR-39 for α-particles at relatively low energies has been established. The investigation included measurements of both bulk- and track-etch rates. The latter was measured as a function of α-particle energies. (author)

  6. 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

    International Nuclear Information System (INIS)

    Amol Mhatre; Kalsi, P.C.

    2011-01-01

    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. (author)

  7. 3D computation of the shape of etched tracks in CR-39 for oblique particle incidence and comparison with experimental results

    International Nuclear Information System (INIS)

    Doerschel, B.; Hermsdorf, D.; Reichelt, U.; Starke, S.; Wang, Y.

    2003-01-01

    Computation of the shape of etch pits needs to know the varying track etch rate along the particle trajectories. Experiments with alpha particles and 7 Li ions entering CR-39 detectors under different angles showed that this function is not affected by the inclination of the particle trajectory with respect to the normal on the detector surface. Track formation for oblique particle incidence can, therefore, be simulated using the track etch rates determined for perpendicular incidence. 3D computation of the track shape was performed applying a model recently described in literature. A special program has been written for computing the x,y,z coordinates of points on the etch pit walls. In addition, the etch pit profiles in sagittal sections as well as the contours of the etch pit openings on the detector surface have been determined experimentally. Computed and experimental results were in good agreement confirming the applicability of the 3D computational model in combination with the functions for the depth-dependent track etch rates determined experimentally

  8. The Effect of Radiator on CR-39 Registration of Fast Neutrons

    International Nuclear Information System (INIS)

    El-Badrya, B.A.; Hegazya, T.M.; Morsya, A.A.; Zaki, M.F.

    2008-01-01

    Three different configurations of a personal neutron dosimeter using CR-39 plastic detector were placed in Plastiplast pouch composed from inside to outside of Aluminum ( 27 Al, 40 Ξ m), polyethylene (PE, 20 Ξ m), Cellulose Nitrate (CN, 40 Ξ m). One dosimeter was composed of a CR-39 detector and a PE radiator (1 mm thick), another of two CR-39 detectors with one serving as radiator, and the other of CR-39 alone (without radiator). These dosimeters have been irradiated with fast neutrons of average energy 4.5 MeV with neutron fluence ranging from 5.5 x 10 6 to 0.5 x 10 8 cm - 2 emitted from 241 Am-Be neutron source. The polymeric materials have been chosen on the basis of their hydrogen contents, which are as followed: CR-39, 48%, Polyethylene, 66.7% and CN, 32% by atomic ratio to produce protons via (n, p) elastic scattering with hydrogen and increasing the detection efficiency of CR-39. After irradiation, the dose equivalent response of the detectors has been studied by using conventional etching for two periods, 6h and 8h for these configurations. The thicknesses and compositions of the radiators are chosen so as to suppress the CR-39 response below 4 MeV by preventing the recoils of hydrogen nuclei, out of the hydrogen-rich radiators (PE, CR-39), from reaching the post-etch surface of the detector. Track counting was performed using an automated system. It was found that the dosemeter responses were linear as a function of a neutron equivalent dose and that the CR-39 detector has the same response with radiator or without radiator and thus appears as a promising fast neutron dosimeter. The results are discussed and compared with the literature

  9. Effects of additives and impurities on the properties of CR-39 neutron dosimeters

    International Nuclear Information System (INIS)

    Tarle, G.

    1982-01-01

    Several problems have plagued users of commercial CR-39 for neutron dosimetry work. Large variations in sensitivity have been observed in samples received from different manufacturers, from different batches from the same manufacturer and even within a given sheet. The latter variations have taken several forms. Clear etching regions of lower sensitivity near the gasket and sometimes extending well away from the gasket in drip-like patterns have been observed. Large demarcated patches of differing sensitivity and sensitivity variations with depth have been found in many commercial samples of CR-39. In addition, we have observed a general roughening of the post-etch surface and a patchiness of bulk etching associated with contact patterns of adjacent sheets, which have been stored for extended (greater than or equal to 6 mos) periods of time. All of these problems combine to make commercially available CR-39 unreliable as a neutron dosimeter. In an attempt to identify and correct the causes of these problems, a systematic study of the effects of additives, impurities and manufacturing conditions on the uniformity of CR-39 track detectors has been undertaken, and is reported in this paper

  10. Characteristics of latent damage trails due to high energy 208Pb and 238U ions in CR-39 and muscovite mica

    International Nuclear Information System (INIS)

    Chohan, A.S.; Akhtar, S.M.

    1988-01-01

    Experiments have been performed to study the characteristics of latent damage trails produced by (a) 17.14 MeV/nucleon- 208 Pb ions in mica and CR-39 track detectors and (b) 13.7 MeV/nucleon- 238 U in CR-39 track detectors. The parameters studied include (a) V t , average etching velocity along the track, (b) thermal stability of the latent damage trails, (c) the total etchable ranges, and (d) V g the general etching velocity of CR-39 track detectors previously annealed at different temperatures. It has been observed that the latent damage trails in CR-39 are greatly affected at temperatures around 200 0 C in CR-39 track detectors. The general etching velocity of a CR-39 detector has been found to increase with increasing annealing temperatures. (author)

  11. Detection of heavy nuclei in the plastic track detector CR-39

    International Nuclear Information System (INIS)

    Fumuro, F.; Ihara, R.; Ohta, I.; Sato, Y.; Tezuka, I.; Tasaka, S.; Sugimoto, H.

    1982-01-01

    Relativistic cosmic ray nuclei were detected in an emulsion chamber composed of a pile of solid state track detectors (CR-39) and the emulsion plates. The 460 heavy nuclei were observed by scanning of emulsion and CR-39 plastic plates. The normalized track etch rate (Vsub(t)/Vsub(b))-1 for relativistic iron group was measured as 1.3+-0.05 and bulk etch rate Vsub(b) as 1.63+-0.08 μm/hour after 32 hours etch in 6.8 N NaOH at 70 0 C. The charge detection threshold was obtained to be Z=6 for β=1 with the dip angle larger than 75 degrees. The charge resolution was estimated to be Δ Z=0.7 for iron, and Δ Z=0.4 for magnesium and silicon nuclei

  12. Effect of Gamma Rays on Fast Neutron Registration in CR-39

    CERN Document Server

    Kobzev, A P; El-Halem, A A; Abdul-Ghaphar, U S; Salama, T A

    2002-01-01

    A set of CR-39 plastic detectors with front PE radiator was exposed to Am-Be neutron source, which has an emission rate of 0.86\\cdot 10^{7} sec^{-1}, and the neutron dose equivalent rate 1 m apart from the source is equal to 11 mrem/hr. Another set of samples was irradiated by a neutron dose of 4 rem, then exposed to different gamma-ray doses using ^{60}Co source. It was found that the track density grows with the increase of neutron dose and etching time. It was also found that the bulk etching rate V_{B}, the track diameter and the sensitivity of the CR-39 plastic detector with respect to the neutron irradiation increased with increasing gamma-ray dose in the range 1?10 Mrad. These results show that CR-39 can be considered as a promising fast neutron dosimeter and gamma-ray dosimeter.

  13. Alkaline erosion of CR 39 polymer surfaces

    International Nuclear Information System (INIS)

    Faiman, Laurence

    2009-01-01

    We have investigated the mechanism of erosion of CR 39 polymer in alkaline environments. We observed the kinetics of absorption of water and methanol into both unirradiated and γ-irradiated samples. We use a capillary model to interpret our results. We etched our samples in both KOH solutions, and KOH solutions doped with methanol. Etch rate was desensitizing to γ-irradiation when KOH concentration approached saturation, but KOH solutions doped with methanol were not desensitizing, unlike with nuclear tracks. We account for this difference

  14. Development of neutron dosimeter using CR-39 for measurement of ambient dose equivalent

    International Nuclear Information System (INIS)

    Maki, Daisuke; Shinozaki, Wakako; Ohguchi, Hiroyuki; Yamamoto, Takayoshi; Nakamura, Takayoshi

    2010-01-01

    A CR-39 has good advantages such as cumulative type dosimeter, small fading effect and gamma-ray insensitive. Therefore, we developed the wide energy-range environmental neutron dosimeter using eight CR-39s for area monitoring in this study. This dosimeter is made of octagonal columnar polyethylene block which height is 60 mm and bottom side is 25 mm. The dosimeter contains two types of CR-39s for fast neutron detection and slow neutron detection. Four CR-39s for fast neutron detection are used for detection of recoil protons produced by H (n, p) reactions. Four CR-39s for slow neutron detection are used with boron nitride converter to detect alpha-rays produced by 10 B (n, α) 7 Li reactions. Ambient dose equivalent is obtained by adding the number of etch-pits observed in four CR-39s for fast neutron detection to the number of etch-pits observed in four CR-39s for slow neutron detection with appropriate constants respectively. Dosimeters were irradiated with some energetic neutrons and evaluated results of ambient dose equivalent were compared with results from neutron transport calculations. Energy response of dosimeter shows good agreement with neutron fluence to ambient dose equivalent conversion coefficients. Directional dependence of dosimeter is at the same level as the rem-counter. (author)

  15. Background tracks in CR-39 SSNTD sheets: their control and prediction through an interplay of etching parameters

    International Nuclear Information System (INIS)

    Bhagwat, A.M.; Naik, G.R.; Thampan, S.; Rudran, K.; Joshi, V.B.; Iyer, M.R.

    1992-01-01

    High sensitivity of CR-39 film in turn leads to higher and variable background track-densities. A two-step etching process, each consisting of CE and ECE, is therefore suggested which permits not only partial freezing of the background but also allows to know its level. The procedure identifies bad pieces with scratches and determines the minimum detection limit (MDL) of each film individually. Activities as low as 0.2 mBq (∼ 5 x 10 -15 curies) can thus be measured with low background films for exposure periods of 7-10 days (exposure is carried out after first processing). (author)

  16. Development of hybrid track detector using CR39 and photographic plate

    International Nuclear Information System (INIS)

    Kuge, Kenichi; Endo, Yusuke; Hayashi, Kentaro; Hasegawa, Akira; Kumagai, Hiroshi

    2004-01-01

    Hybrid track detector using CR39 and color photography was prepared by coating multi-layered color photographic emulsions on one side of CR39. Etch pits and color tracks were observed at the same time. Photographic plate with different sensitivity emulsions and couplers were exposed to light, α-, β- and γ-rays. We observed sensitivity difference to the radiation by color changes on one plate. (authors)

  17. CR-39 and Lexan calibrated as low-LET radiation dosimeter, for three Mexican irradiation facilities

    International Nuclear Information System (INIS)

    Tavera, L.; Balcazar, M.; Matamoros, H.; Carrasco, H.

    2005-01-01

    An experimental calibration of two common nuclear track detectors, CR-39 and Lexan, for gamma and electrons radiation, was performed using various irradiation facilities. The dose response was obtained as a function of two parameters, the bulk etch rate and the UV absorbance for a wide dose range from 10 to 1000 kGy. The bulk etch rate sensitivity, for gamma and electrons, in CR-39 detector is higher than for Lexan detector. Lexan has a well-defined UV absorbance spectrum, but presents saturation for doses higher than 500 kGy, the same saturation characteristic is observed for the corresponding bulk etch rate response. For electron and gamma radiation, CR-39 shows a good response for doses from 10 kGy up to 1000 kGy, where data fit well an exponential curve for electrons and a lineal curve for gamma radiation

  18. Fast neutron irradiation effects on CR-39 nuclear track detector for dosimetric applications

    International Nuclear Information System (INIS)

    Kader, M.H.

    2005-01-01

    The effect of neutron irradiation on the dosimetric properties of CR-39 solid-state nuclear track detector have been investigated. CR-39 samples were irradiated with neutrons of energies follow a Maxwellian distribution centered about 2 MeV. These samples were irradiated with different doses in the range 0.1-1 Sv. The background and track density were measured as a function of etching time. In addition, the dependence of sensitivity of CR-39 detector on the neutrons dose has been investigated. The results show that the Sensitivity started to increase at 0.4 Sv neutrons dose, so this sample were chosen to be a subject for further study to investigate the effect of gamma dose on its properties. The sample irradiated with 0.4 Sv were exposed to different doses of gamma rays at levels between 10 and 80 kGy. The effect of gamma doses on the bulk etching rate VB, the track diameter and the sensitivity of the CR-39 samples was investigated. The results show that the dosimetric properties of CR-39 SSNTD are greatly affected by both neutron and gamma irradiation

  19. CR-39 track detector for multi-MeV ion spectroscopy.

    Science.gov (United States)

    Jeong, T W; Singh, P K; Scullion, C; Ahmed, H; Hadjisolomou, P; Jeon, C; Yun, H; Kakolee, K F; Borghesi, M; Ter-Avetisyan, S

    2017-05-19

    We present the characteristics of track formation on the front and rear surfaces of CR-39 produced by laser-driven protons and carbon ions. A methodological approach, based on bulk etch length, is proposed to uniquely characterize the particle tracks in CR-39, enabling comparative description of the track characteristics in different experiments. The response of CR-39 to ions is studied based on the energy dependent growth rate of the track diameter to understand the intrinsic particle stopping process within the material. A large non-uniformity in the track diameter is observed for CR-39 with thickness matching with the stopping range of particles. Simulation and experimental results show the imprint of longitudinal range straggling for energetic protons. Moreover, by exploiting the energy dependence of the track diameter, the energy resolution (δE/E) of CR-39 for few MeV protons and Carbon ion is found to be about 3%.

  20. Detection of light charged particles from plasma focus by CR-39

    Energy Technology Data Exchange (ETDEWEB)

    Antanasijevic, R.; Vukovic, J.; Popovic, S.; Popovic, M. (Belgrade Univ. (Yugoslavia). Inst. za Fiziku); Puric, J.; Cuk, M. (Faculty of Physical Science, Belgrade (Yugoslavia))

    1991-01-01

    An analysis of a deuteron (D{sup +}) beam, emitted from a plasma focus has been carried out, using a CR-39 plastic nuclear track detector. The CR-39 was pretreated using different processes to destroy the existing background before exposing it to the particles produced in the plasma focus. From measurements of the diameters of the tracks, the estimated energy of the D{sup +} ions is about 0.5 MeV. The total number of emitted D{sup +} ions was 10 particles/pulse. Some preliminary results on imaging etched CR-39 with an Atomic Force Microscope (NanoScope AFM) are also presented. (author).

  1. Detection of light charged particles from plasma focus by CR-39

    International Nuclear Information System (INIS)

    Antanasijevic, R.; Vukovic, J.; Popovic, S.; Popovic, M.

    1991-01-01

    An analysis of a deuteron (D + ) beam, emitted from a plasma focus has been carried out, using a CR-39 plastic nuclear track detector. The CR-39 was pretreated using different processes to destroy the existing background before exposing it to the particles produced in the plasma focus. From measurements of the diameters of the tracks, the estimated energy of the D + ions is about 0.5 MeV. The total number of emitted D + ions was 10 particles/pulse. Some preliminary results on imaging etched CR-39 with an Atomic Force Microscope (NanoScope AFM) are also presented. (author)

  2. Simple preparation of thin CR-39 detectors for alpha-particle radiobiological experiments

    International Nuclear Information System (INIS)

    Chan, K.F.; Lau, B.M.F.; Nikezic, D.; Tse, A.K.W.; Fong, W.F.; Yu, K.N.

    2007-01-01

    Alpha-particle radiobiological experiments involve irradiating cells with alpha particles and require accurate positions where the alpha particles hit the cells. In the present work, we prepared thin CR-39 detectors from commercially available CR-39 SSNTDs with a thickness of 100 μm by etching them in 1 N NaOH/ethanol at 40 deg. C to below 20 μm. The desired final thickness was achieved within ∼8 h. Such etching conditions can provide relatively small roughness of the detector as revealed by atomic force microscope, and thus provide transparent detectors for radiobiological experiments. UV radiation was employed to shorten track formation time on these thin CR-39 detectors. After exposure to UV light (UVA + B radiation) for 2-3 h with doses from 259 to 389 W/cm 2 , 5 MeV alpha-particle tracks can be seen to develop on these CR-39 detectors clearly under the optical microscope within 2 h in 14 N KOH at 37 deg. C. As an example for practical use, custom-made petri dishes, with a hole drilled at the bottom and covered with a thin CR-39 detector, were used for culturing HeLa cells. The feasibility of using these thin CR-39 detectors is demonstrated by taking photographs of the cells and alpha-particle tracks together under the optical microscope, which can allow the hit positions on the cells by the alpha particles to be determined accurately

  3. Suitability of CR-39 dosimeters for personal dosimetry around CANDU reactors

    International Nuclear Information System (INIS)

    Cross, W.G.

    1992-08-01

    The capabilities and limitations of CR-39 damage track detectors have been evaluated for their use as personal neutron dosimeters around CANDU reactors. Since the energy response is a critical characteristic, the neutron energy spectra expected within CANDU containments were studied. In the boiler rooms, around the moderator cooling systems, and in most of the fueling machine vaults, the spectra vary considerably, but the majority of the dose is expected to be delivered by neutrons above 80 keV, the approximate threshold for electrochemically-etched CR-39 detectors. In the Pickering A fueling machine vault, and in areas in other stations to which neutrons from reactors have been multiply scattered, lower energy neutrons may be important. In nearly all areas where people work, it appears that working times will be limited by gamma rays rather than by neutrons. The characteristics of other neutron dosimeters - bubble and superheated drop detectors, albedo detectors, and Si real-time detectors - were also reviewed. For workers who typically receive neutron doses that are small compared with regulatory limits, CR-39 is the most suitable available dosimeter for demonstrating compliance. All single dosimeters have poor angular response over the range 0 to 180 degrees because of the shielding of the body. Albedo and Si detectors have particularly poor energy responses over the energy range of importance. Bubble and superheated drop detectors have the advantages of immediate readout and high sensitivity, but the disadvantages of inability to integrate doses over a long period, temperature dependence, very limited range and higher cost. (Author) (110 refs., 45 figs.)

  4. Range to cone length relations for light ions in CR-39

    International Nuclear Information System (INIS)

    Gil, L.R.; Marques, A.

    1988-01-01

    Curves ''range x cone lenght'' and ''diameter x cone lenght'' are calculated for tracks left by low energy light ions in CR-39. The calculations cover ions from helium to iron and are performed for 6.25 N NaOH at 70 0 C and a standard etching time but can be easily extended to other etching conditions. (author) [pt

  5. Neutron dosimetry using electrochemical etching

    International Nuclear Information System (INIS)

    Su, S.J.; Stillwagon, G.B.; Morgan, K.Z.

    1977-01-01

    Registration of α-tracks and fast-neutron-induced recoils tracks by the electrochemical etching technique as applied to sensitive polymer foils (e.g., polycarbonate) provides a simple, sensitive and inexpensive means of fast neutron personnel dosimetry as well as a valuable research tool for microdosimetry. When tracks were amplified by our electrochemical technique and the etching results compared with conventional etching technique a striking difference was noted. The electrochemically etched tracks were of much larger diameter (approx. 100 μm) and gave superior contrast. Two optical devices--the transparency projector and microfiche reader--were adapted to facilitate counting of the tracks appearing on our polycarbonate foils. The projector produced a magnification of 14X for a screen to projector distance of 5.0 meter and read's magnification was 50X. A Poisson distribution was determined for the number of tracks located in a particular area of the foil and experimentally verified by random counting of quarter sections of the microfiche reader screen. Finally, in an effort to determine dose equivalent (rem), a conversion factor is being determined by finding the sensitivity response (tracks/neutron) of recoil particle induced tracks as a function of monoenergetic fast neutrons and comparing results with those obtained by others

  6. Alpha particle track coloration in CR-39: Improved observability

    CERN Document Server

    Oezguemues, A

    1999-01-01

    A comparative study of the observability of alpha particle tracks in CR-39 was performed with an optical microscope before and after coloration. The implantation of ink helped in observing the damage zones. At first glance through the microscope, the coloration makes the tracks stand out right away. This coloration is helpful, from the start, in the morphological study of the tracks (size, area, orientation, shape, perimeter). This operation is advantageous in distinguishing the alpha particle tracks from stains or scratches. Thus, the routine counting of the tracks is more easily performed. Consequently, this procedure allowed us: to decrease significantly the standard deviation of the approximate total of the parameters given from the image analysis system (Olympus CUE2); to envision the possibility of reasonably decreasing the etching time in order to limit the loss of information caused by the destruction of the CR-39 during chemical etching and to use a weaker enlarging lens in order to cover a larger fi...

  7. The response of CR-39 nuclear track detector to 1-9 MeV protons

    International Nuclear Information System (INIS)

    Sinenian, N.; Rosenberg, M. J.; Manuel, M.; McDuffee, S. C.; Casey, D. T.; Zylstra, A. B.; Rinderknecht, H. G.; Gatu Johnson, M.; Seguin, F. H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D.

    2011-01-01

    The response of CR-39 nuclear track detector (TasTrak) to protons in the energy range of 0.92-9.28 MeV has been studied. Previous studies of the CR-39 response to protons have been extended by examining the piece-to-piece variability in addition to the effects of etch time and etchant temperature; it is shown that the shape of the CR-39 response curve to protons can vary from piece-to-piece. Effects due to the age of CR-39 have also been studied using 5.5 MeV alpha particles over a 5-year period. Track diameters were found to degrade with the age of the CR-39 itself rather than the age of the tracks, consistent with previous studies utilizing different CR-39 over shorter time periods.

  8. Alpha-particle radiobiological experiments using thin CR-39 detectors

    International Nuclear Information System (INIS)

    Chan, K. F.; Siu, S. Y. M.; McClella, K. E.; Tse, A. K. W.; Lau, B. M. F.; Nikezic, D.; Richardson, B. J.; Lam, P. K. S.; Fong, W. F.; Yu, K. N.

    2006-01-01

    The present paper studied the feasibility of applying comet assay to evaluate the DNA damage in individual HeLa cervix cancer cells after alpha-particle irradiation. We prepared thin CR-39 detectors (<20 μm) as cell-culture substrates, with UV irradiation to shorten the track formation time. After irradiation of the HeLa cells by alpha particles, the tracks on the underside of the CR-39 detector were developed by chemical etching in (while floating on) a 14 N KOH solution at 37 deg. C. Comet assay was then applied. Diffusion of DNA out of the cells could be generally observed from the images of stained DNA. The alpha-particle tracks corresponding to the comets developed on the underside of the CR-39 detectors could also be observed by just changing the focal plane of the confocal microscope. (authors)

  9. Alpha particle radiography and the track plastic detector CR-39

    International Nuclear Information System (INIS)

    Souza, Bismarck Amilar de.

    1991-05-01

    This work develops the radiographic technique using charged particle beams. This technique complements the X-ray conventional radiography, and presents some advantages in certain cases. The material used as nuclear plastic detector was CR-39, manufactured by Pershre Mould. England, of 250 and 1000 μm nominal thicknesses. The irradiations were made with 7 MeV/Nucleon alpha particles beams, accelerated in the CV-28 Cyclotron of Instituto de Engenharia Nuclear/CNEN - Rio de Janeiro. The etch conditions used were a Na OH 6,25 N solution at 70 0 C, varying the etch time, so that the best etch time was found to be six hours. The calibration curve is presented, which permits images interpretation, showed in terms of light transmittance (obtained using a micro densitometer), and in terms of energy losses suffered by alpha particles in several aluminum degradating thicknesses. This curve was checked by the use of other degradating materials: Mylar, Makrofol, and CR-39 itself. The influence of alpha particle beam FWHM widening on images quality, when it crosses several degradating materials, is also presented. Radiographs of some specimen are presented, including some images obtained varying some irradiation and etch parameters. (author). 62 refs., 22 figs., 19 tabs

  10. CR-39 nuclear track detector used for neutron dosimetry: system calibration

    International Nuclear Information System (INIS)

    Saint Martin, G.; Lopez, F.; Bernaola, Omar A.

    2009-01-01

    Stacks composed by 1 mm thickness CR-39 foils and polyethylene and PVC films were evaluated to be used as neutron dosemeters. Irradiations were made with a calibrated 241 Am-Be source in a dose range from 0 to 3.1 mSv and the etching conditions were optimized. The measurements of number of tracks per surface unit in the CR-39 detectors showed a good linear behaviour as a function of the dose. The minimum detectable dose equivalent (MDDE) was calculated. (author)

  11. Micropatterning on cylindrical surfaces via electrochemical etching using laser masking

    International Nuclear Information System (INIS)

    Cho, Chull Hee; Shin, Hong Shik; Chu, Chong Nam

    2014-01-01

    Highlights: • Various micropatterns were fabricated on the cylindrical surface of a stainless steel shaft. • Selective electrochemical dissolution was achieved via a series process of laser masking and electrochemical etching. • Laser masking characteristics on the non-planar surface were investigated. • A uniform mask layer was formed on the cylindrical surface via synchronized laser line scanning with a rotary system. • The characteristics of electrochemical etching on the non-planar surface were investigated. - Abstract: This paper proposes a method of selective electrochemical dissolution on the cylindrical surfaces of stainless steel shafts. Selective electrochemical dissolution was achieved via electrochemical etching using laser masking. A micropatterned recast layer was formed on the surface via ytterbium-doped pulsed fiber laser irradiation. The micropatterned recast layer could be used as a mask layer during the electrochemical etching process. Laser masking condition to form adequate mask layer on the planar surface for etching cannot be used directly on the non-planar surface. Laser masking condition changes depending on the morphological surface. The laser masking characteristics were investigated in order to form a uniform mask layer on the cylindrical surface. To minimize factors causing non-uniformity in the mask layer on the cylindrical surface, synchronized laser line scanning with a rotary system was applied during the laser masking process. Electrochemical etching characteristics were also investigated to achieve deeper etched depth, without collapsing the recast layer. Consequently, through a series process of laser masking and electrochemical etching, various micropatternings were successfully performed on the cylindrical surfaces

  12. The chemical and electrochemical anisotropic etching of silicon

    International Nuclear Information System (INIS)

    Dixon, E.

    1997-06-01

    The success of silicon IC technology in producing a wide variety of microstructures relies heavily on the orientation dependant etching observed for silicon in alkaline media. Despite the rapid growth of this industry, the chemical and electrochemical mechanisms by which anisotropic etching occurs remain poorly understood. The most common etchant systems in use are ethylenediamine-pyrocatechol-water (EPW) and potassium hydroxide-isopropanol-water (KOH-IPA), and whilst these systems are highly plane selective they each have distinct disadvantages. The occurrence of inhomogeneities such as micropyramids and pits on the surface of etched substrates is a particularly disadvantageous characteristic of many alkaline etching systems. A complete understanding of the chemical and electrochemical anisotropic etching mechanisms is essential in order to obtain more reproducible etching, improved etch rate ratios and the development of more reliable etching baths. Wet chemical etching experiments to evaluate the etching rates for the different alkali metal cations have shown that similar etch rates are observed for LiOH, NaOH and KOH but those of RbOH and CsOH are significantly lower. The presence of impurities was shown to worsen the etched wafer's surface finish obtained in these etching baths. Additives have been shown to dramatically improve the surface finish with the presence of IPA in conjunction with etchant oxygenation virtually eliminating all surface defects. Electrochemical experiments were used to assess the electrochemical behaviour of Si p-(100) in of a wide variety of etchants and variations were seen according to the etchant used. A.C impedance spectroscopy showed a variation in the flat-band potential (V FB ) according to alkali metal hydroxide etchant used. These trends were similarly observed in the presence of isopropanol. Oxygenation was observed to reproducibly alter the flat-band potentials. A.c impedance spectroscopic studies additionally confirmed the

  13. Application of CR-39 to radon measurement

    International Nuclear Information System (INIS)

    Miyake, Hiroshi

    1988-01-01

    CR-39, an ally diglycol carbonate, has recently come into wider use as material for solid-state track detector. Etching with NaOH or KOH solution allow CR-39 to develop extremely clear etch pits attributed to alpha rays. The most widely used method for measuring radon concentration employs a plastic cup with a solid-state track detector mounted at its bottom to detect alpha rays resulting from radon or its daughters that disintegrate within or on the wall of the cup. Simple in mechanism and low in cost, this method is suitable for such a case where the radon concentration distribution over a wide area has to be measured by using a large number of devices. The concentration of radon alone can be measured with the aid of a filter attached to the mouth of the cup to remove the daughters of radon and thoron. The simplest and most effective way of improving the sensitivity of a solid-state track detector for radon concentration measurement is to electrostatically collect daughters resulting from decay of radon onto the surface of the detector. Another method widely used to determine the radon concentration is to measure the concentration of the radon daughters instead of direct measurement of the concentration of radon itself. (Nogami, K.)

  14. Response of CR-39 to 0.9-2.5 MeV protons for KOH and NaOH etching solutions

    Science.gov (United States)

    Bahrami, F.; Mianji, F.; Faghihi, R.; Taheri, M.; Ansarinejad, A.

    2016-03-01

    In some circumstances passive detecting methods are the only or preferable measuring approaches. For instance, defining particles' energy profile inside the objects being irradiated with heavy ions and measuring fluence of neutrons or heavy particles in space missions are the cases covered by these methods. In this paper the ability of polyallyl diglycol carbonate (PADC) track detector (commercially known as CR-39) for passive spectrometry of proton particles is studied. Furthermore, the effect of KOH and NaOH as commonly used chemical etching solutions on the response of the detector is investigated. The experiments were carried out with protons in the energy range of 0.94-2.5 MeV generated by a Van de Graaff accelerator. Then, the exposed track dosimeters were etched in the two aforementioned etchants through similar procedure with the same normality of 6.25 N and the same temperature of 85 °C. Formation of the tracks was precisely investigated and the track diameters were recorded following every etching step for each solution using a multistage etching process. The results showed that the proposed method can be efficiently used for the spectrometry of protons over a wider dynamic range and with a reasonable accuracy. Moreover, NaOH and KOH outperformed each other over different regions of the proton energy range. The detection efficiency of both etchants was approximately 100%.

  15. Charge resolution of a Hungarian brand CR-39(MA-ND) detector exposed to a 84Kr beam of energy 0.45A GeV

    International Nuclear Information System (INIS)

    Bhattacharyya, D.P.; Basu, B.; Pal, P.; Mukherjee, S.C.; Ganguly, A.K.; Hunyady, I.

    1990-01-01

    The Hungarian brand CR-39(MA-ND) plastic has been irradiated with a 84 Kr ion beam of energy 0.45A GeV and etched for four different etching times, viz. 4, 6, 8 and 12 h. The estimated charge resolution of a CR-39(MA-ND) detector for registering the nuclei 32 ≤ Z ≤ 36 was found to be 0.18e which is close to our previous observation of the response with a CR-39(DOP) Pershore made plate exposed to a 1.88A GeV 56 Fe beam at the Lawrence Berkeley Laboratory's Bevalac. It was found that the estimated etch rate ratio V T /V G is independent of etching time. The cone length and minor axis of the etch pits has been found to increase with etching time. (orig.)

  16. LET spectrum measurements in Cr-39 PNTD with AFM

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Carl Edward [Los Alamos National Laboratory; De Witt, Joel M [OSU, PHYSICS; Benton, Eric R [OSU, PHYSICS; Yasuda, Nakahiro [NIRS, HIMAC; Benton, Eugene V [UNIV OF SAN FRANCISCO

    2010-01-01

    Energetic protons, neutrons, and heavy ions undergoing collisions with target nuclei of varying Z can produce residual heavy recoil fragments via intra-nuclear cascade/evaporation reactions. The particles produced in these non-elastic collisions generally have such extremely short range ({approx}< 10 {mu}m) that they cannot be directly observed by conventional detection methods including CR-39 plastic nuclear track detector (PNTD) that has been chemically etched for analysis by standard visible light microscopy. However, high-LET recoil fragments having range on the order of several cell diameters can be produced in tissue during radiotherapy using proton and carbon beams. We have developed a method to analyze short-range, high-LET tracks in CR-39 plastic nuclear track detector (PNTD) using short duration chemical etching ({approx}< 1 {mu}m) followed by automated atomic force microscope (AFM) scanning. The post-scan data processing used in this work was based on semi-automated matrix analysis opposed to traditional grey-scale image analysis. This method takes advantage of the 3-D data obtained via AFM to achieve robust discrimination of nuclear tracks from other features. Through automation of AFM scanning, sufficient AFM scan frames were obtained to attain an LET spectrum spanning the LET range from 200-1500 keV/{mu}m. In addition to our experiments, simulations were carried out with the Monte Carlo transport code, FLUKA. To demonstrate this method, CR-39 PNTD was exposed to the proton therapy beam at Loma Linda University Medical Center (LLUMC) at 60 and 230 MeV. Additionally, detectors were exposed to I GeV protons at the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL). For these exposures CR-39 PNTD, Al and Cu target foils were used between detector layers.

  17. LET spectrum measurements in Cr-39 PNTD with AFM

    International Nuclear Information System (INIS)

    Johnson, Carl Edward; DeWitt, Joel M.; Benton, Eric R.; Yasuda, Nakahiro; Benton, Eugene V.

    2010-01-01

    Energetic protons, neutrons, and heavy ions undergoing collisions with target nuclei of varying Z can produce residual heavy recoil fragments via intra-nuclear cascade/evaporation reactions. The particles produced in these non-elastic collisions generally have such extremely short range (∼< 10 μm) that they cannot be directly observed by conventional detection methods including CR-39 plastic nuclear track detector (PNTD) that has been chemically etched for analysis by standard visible light microscopy. However, high-LET recoil fragments having range on the order of several cell diameters can be produced in tissue during radiotherapy using proton and carbon beams. We have developed a method to analyze short-range, high-LET tracks in CR-39 plastic nuclear track detector (PNTD) using short duration chemical etching (∼< 1 μm) followed by automated atomic force microscope (AFM) scanning. The post-scan data processing used in this work was based on semi-automated matrix analysis opposed to traditional grey-scale image analysis. This method takes advantage of the 3-D data obtained via AFM to achieve robust discrimination of nuclear tracks from other features. Through automation of AFM scanning, sufficient AFM scan frames were obtained to attain an LET spectrum spanning the LET range from 200-1500 keV/μm. In addition to our experiments, simulations were carried out with the Monte Carlo transport code, FLUKA. To demonstrate this method, CR-39 PNTD was exposed to the proton therapy beam at Loma Linda University Medical Center (LLUMC) at 60 and 230 MeV. Additionally, detectors were exposed to I GeV protons at the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL). For these exposures CR-39 PNTD, Al and Cu target foils were used between detector layers.

  18. On registration properties of Intercast Company CR-39

    International Nuclear Information System (INIS)

    Golovchenko, A.N.

    1991-01-01

    The CR-39 response function has been determined by using the accelerated particles of intermediate ( 2 H, 4 He, 12 C, 16 O, 20 Ne and 40 Ar) and relativistic ( 19 F) energies. The irradiated detectors were etched in 6N NaOH kept at 70 deg C. The response function is determined in a wide range of the ionization change. 10 refs.; 1 fig.; 2 tabs

  19. 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

    International Nuclear Information System (INIS)

    Kalsi, P.C.

    2010-01-01

    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 (K wet ) 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, V b 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

  20. Electro-regeneration of Ce(IV) in real spent Cr-etching solutions

    International Nuclear Information System (INIS)

    Chen, Te-San; Huang, Kuo-Lin

    2013-01-01

    Highlights: • An electrochemical process is used to regenerate Ce(IV) in real (hazardous) spent TFT-LCD Cr-etching solutions. • The Ce(IV) yield on tested anodes was in order BDD > Pt > DSA. • A Neosepta CMX separator was better than Nafion ones to be used in the process. • The activation energy on Pt was 10.7 kJ/mol. • The obtained parameters are useful to design reactors for 100% Ce(IV) regeneration in real spent Cr-etching solutions. -- Abstract: This paper presents the electro-regeneration of Ce(IV) in real (hazardous) spent thin-film transistor liquid-crystal display (TFT-LCD) Cr-etching solutions. In addition to Ce(III) > Ce(IV) in diffusivity, a quasi-reversible behavior of Ce(III)/Ce(IV) was observed at both boron-doped diamond (BDD) and Pt disk electrodes. The Ce(IV) yield on Pt increased with increasing current density, and the best current efficiency (CE) was obtained at 2 A/2.25 cm 2 . The performance in terms of Ce(IV) yield and CE of tested anodes was in order BDD > Pt > dimensional stable anode (DSA). At 2 A/2.25 cm 2 on Pt and 40 °C for 90 min, the Ce(IV) yield, CE and apparent rate constant (k) for Ce(III) oxidation were 81.4%, 21.8% and 3.17 × 10 −4 s −1 , respectively. With the increase of temperature, the Ce(IV) yield, CE, and k increased (activation energy = 10.7 kJ/mol), but the specific electricity consumption decreased. The Neosepta CMX membrane was more suitable than Nafion-117 and Nafion-212 to be used as the separator of the Ce(IV) regeneration process. The obtained parameters are useful to design divided batch reactors for the Ce(IV) electro-regeneration in real spent Cr-etching solutions

  1. Two-step controllable electrochemical etching of tungsten scanning probe microscopy tips

    KAUST Repository

    Khan, Yasser; Al-Falih, Hisham; Ng, Tien Khee; Ooi, Boon S.; Zhang, Yaping

    2012-01-01

    Dynamic electrochemical etching technique is optimized to produce tungsten tips with controllable shape and radius of curvature of less than 10 nm. Nascent features such as dynamic electrochemical etching and reverse biasing after drop-off are utilized, and two-step dynamic electrochemical etching is introduced to produce extremely sharp tips with controllable aspect ratio. Electronic current shut-off time for conventional dc drop-off technique is reduced to ?36 ns using high speed analog electronics. Undesirable variability in tip shape, which is innate to static dc electrochemical etching, is mitigated with novel dynamic electrochemical etching. Overall, we present a facile and robust approach, whereby using a novel etchant level adjustment mechanism, 30° variability in cone angle and 1.5 mm controllability in cone length were achieved, while routinely producing ultra-sharp probes. © 2012 American Institute of Physics.

  2. Response of CR-39 to 0.9–2.5 MeV protons for KOH and NaOH etching solutions

    Energy Technology Data Exchange (ETDEWEB)

    Bahrami, F. [Department of Medical Radiation Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Mianji, F., E-mail: fmianji@aeoi.org.ir [Nuclear Science & Technology Research Institute, Tehran (Iran, Islamic Republic of); Iran Nuclear Regulatory Authority, Tehran (Iran, Islamic Republic of); Faghihi, R. [Department of Medical Radiation Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Taheri, M. [Iran Nuclear Regulatory Authority, Tehran (Iran, Islamic Republic of); Ansarinejad, A. [Nuclear Science & Technology Research Institute, Tehran (Iran, Islamic Republic of)

    2016-03-21

    In some circumstances passive detecting methods are the only or preferable measuring approaches. For instance, defining particles' energy profile inside the objects being irradiated with heavy ions and measuring fluence of neutrons or heavy particles in space missions are the cases covered by these methods. In this paper the ability of polyallyl diglycol carbonate (PADC) track detector (commercially known as CR-39) for passive spectrometry of proton particles is studied. Furthermore, the effect of KOH and NaOH as commonly used chemical etching solutions on the response of the detector is investigated. The experiments were carried out with protons in the energy range of 0.94–2.5 MeV generated by a Van de Graaff accelerator. Then, the exposed track dosimeters were etched in the two aforementioned etchants through similar procedure with the same normality of 6.25 N and the same temperature of 85 °C. Formation of the tracks was precisely investigated and the track diameters were recorded following every etching step for each solution using a multistage etching process. The results showed that the proposed method can be efficiently used for the spectrometry of protons over a wider dynamic range and with a reasonable accuracy. Moreover, NaOH and KOH outperformed each other over different regions of the proton energy range. The detection efficiency of both etchants was approximately 100%.

  3. High resolution alpha-autoradiography for measurement of 10B distribution in subcellular scale using CR-39 and AFM

    International Nuclear Information System (INIS)

    Amemiya, K.; Takahashi, H.; Yasuda, N.

    2000-01-01

    In order to measure 10 B distribution in tumor tissues for BNCT at subcellular scale, we have developed a new method for high resolution alpha-autoradiography using contact X-ray microscopy technique with CR-39 plastic track detectors. Sliced sections of boron-injected brain tumors in rats were mounted on CR-39 and irradiated with thermal neutrons at KUR. Then the samples were exposed to soft X-rays from a laser plasma source. After etching the CR-39 in NaOH solution for a short time (1-5 min.), transmission X-ray image of tumor cells appeared as relief on CR-39 surface, and could be observed with the atomic force microscopy (AFM). Very small etch pits of about 100 nm in diameter corresponding to particle tracks from 10 B(n, α) 7 Li reactions were also observed in the image simultaneously. This method provides an accurate distribution of 10 B inside the cell. (author)

  4. Measuring depths of sub-micron tracks in a CR-39 detector from replicas using Atomic Force Microscopy

    International Nuclear Information System (INIS)

    Yu, K.N.; Ng, F.M.F.; Nikezic, D.

    2005-01-01

    One of the challenging tasks in the application of solid-state nuclear track detectors (SSNTDs) is the measurement of the depth of the tracks, in particular, the shallow ones resulting from short etching periods. In the present work, a method is proposed to prepare replicas of tracks from α particles in the CR-39 SSNTDs and to measure their heights using atomic force microscopy (AFM). After irradiation, the detectors were etched in a 6.25N aqueous solution of NaOH maintained at 70 deg. C. The etched detectors were immersed into a beaker of the replicating fluid, which was placed in a water bath under ultrasonic vibration and maintained at room temperature to facilitate the filling of the etched tracks with the replicating fluid. As an example of application, these results have been used to derive a V function for the CR-39 detectors used in the present study (for the specified etching conditions)

  5. Fast Neutron Dosimetry Using CR-39 Nuclear Track Detector

    International Nuclear Information System (INIS)

    ZAKI, M.; ABDEL-NABY, A.; MORSY, A.

    2010-01-01

    Measurement of the neutron dose in and around the neutron sources is important for the purpose of personnel and environmental neutron dosimetry. In the present study, a method for the measurement of neutron dose using the UV-Vis spectra of CR-39 plastic track detector was investigated. A set of CR-39 plastic detectors was exposed to 252 Cf neutron source, which had the yield of 0.68x10 8 /s, and neutron dose equivalent rate 1m apart from the source is equal to 3.8 mrem/h. The samples were etched for 10 h in 6.25 N NaOH at 70 o C. The absorbance of the etched samples was measured using UV-visible spectrophotometer as a function of neutron dose. It was observed that there was a linear relationship between the optical absorption of these detectors and neutron dose. This means that the exposure dose of neutron can be determined by knowing the optical absorption of the sample. These results were compared with previous study. It was found that there was a matching and good agreement with their investigations.

  6. Calculating CR-39 Response to Radon in Water Using Monte Carlo Simulation

    International Nuclear Information System (INIS)

    Razaie Rayeni Nejad, M. R.

    2012-01-01

    CR-39 detectors are widely used for Radon and progeny measurement in the air. In this paper, using the Monte Carlo simulation, the possibility of using the CR-39 for direct measurement of Radon and progeny in water is investigated. Assuming the random position and angle of alpha particle emitted by Radon and progeny, alpha energy and angular spectrum that arrive at CR-39, the calibration factor, and the suitable depth of chemical etching of CR-39 in air and water was calculated. In this simulation, a range of data were obtained from SRIM2008 software. Calibration factor of CR-39 in water is calculated as 6.6 (kBq.d/m 3 )/(track/cm 2 ) that is corresponding with EPA standard level of Radon concentration in water (10-11 kBq/m 3 ). With replacing the skin instead of CR-39, the volume affected by Radon and progeny was determined to be 2.51 mm 3 for one m 2 of skin area. The annual dose conversion factor for Radon and progeny was calculated to be between 8.8-58.8 nSv/(Bq.h/m 3 ). Using the CR-39 for Radon measurement in water can be beneficial. The annual dose conversion factor for Radon and progeny was calculated to be between 8.8-58.8 nSv/ (Bq.h/m 3 ).

  7. Cutting thin sheets of allyl diglycol carbonate (CR-39) with a CW CO2, laser

    International Nuclear Information System (INIS)

    Kukreja, L.M.; Bhawalkar, D.D.; Basu, C.; Goswami, J.N.

    1984-01-01

    Recent studies have shown that Allyl Diglycol Carbonate, commercially known as CR-39 (the most sensitive among etch track detectors) can detect relativistic oxygen and other heavier nuclei. We are using large sheets of special grade CR-39 (DOP) in our experiment in Space Shuttle-Spacelab-3. As CR-39 is a highly brittle substance, special care is required to cut CR-39 shetts, especially in case of large sheets and circular cuts. A study of cutting of CR-39 sheets using laser light is described in this paper. It has been found that this method is sufficiently fast to handle large number of sheets and also equally safe for big sheets. A maximum speed up to 200 cm/min with a 5 x 10 4 W/cm 2 laser is obtained during the present study. This study also shows that laser cutting does not affect the track properties of CR-39. (orig.)

  8. Status of development in the field of Cr-39 track detectors

    International Nuclear Information System (INIS)

    Somogyi, G.

    1982-01-01

    The present situation concerning the manufacture and etching characteristics of the CR-39 nuclear track detector is surveyed. Especial attention is paid to the trends in research and to the outstanding questions related to the subject. The requirements and procedures in connection with the manufacture of high-quality, thick and thin detector foils are discussed. The main bulk and track etching characteristics are presented, involving the effects of various environmental parameters as well. A statistical account of the typical directions in application is given. (author)

  9. Tetraethyl ammonium hydroxide (TEAH) as etchant of CR-39 for the determination of fluence of alpha particles

    Energy Technology Data Exchange (ETDEWEB)

    Joshirao, Pranav M.; Vyas, Chirag K.; Eappen, K.P. [Department of Energy Science, Sungkyunkwan University, Suwon 440746 (Korea, Republic of); Shin, Jae Won [Department of Physics, Sungkyunkwan University, Suwon 440746 (Korea, Republic of); Hong, Seung-Woo [Department of Energy Science, Sungkyunkwan University, Suwon 440746 (Korea, Republic of); Department of Physics, Sungkyunkwan University, Suwon 440746 (Korea, Republic of); Manchanda, Vijay K., E-mail: vkm49@skku.edu [Department of Energy Science, Sungkyunkwan University, Suwon 440746 (Korea, Republic of); School of Electronics and Electrical Engineering, Sungkyunkwan University, Suwon 440746 (Korea, Republic of)

    2014-04-01

    Highlights: • Etching time of CR-39 with TEAH–NaOH mixture (at 80 °C) is less than 20 min. • Etched products enhance etching rate. • V{sub B} and V{sub T} values increase exponentially with temperature. • Activation energy of bulk etching and track etching were determined as 0.87 ± 0.02 eV. - Abstract: Choice of chemical etchant and temperature are pivotal to the successful employment of organic/polymeric solid state nuclear track detectors for determining the fluence of charged particles like protons, alpha and other heavy ions. Poly(diethyleneglycol-bis-(allylcarbonate)) (CR-39) is one of the most sensitive detectors for monitoring the alpha particles but suffers from the drawback of long etching period. An attempt has been made in the present work to investigate a mixture, 20% (v/v) tetraethylammonium hydroxide (40%) – 80% NaOH (6 M) (TEAH–NaOH) at varying temperature as an alternate etchant. It was found that bulk/track etch rate increased and as a consequence etching time decreased significantly (about 10 times) when the mixture was used at 80 °C. Mechanistically, improved efficiency of TEAH–NaOH was attributed to its larger organophilicity and lower etching activation energy as compared to NaOH.

  10. Some characteristics of the CR-39 solid state nuclear - Track Detector for register of protons and low energy alpha particles

    International Nuclear Information System (INIS)

    Fonseca, E.S. da.

    1983-01-01

    Experimental results related to registration properties of the CR-39 Solid State Nuclear Track Detector for charged particles are presented and discussed. The existence of an inverse proportion between the induction time and the temperature as well as normal concentration of solutions, is showed by the study of CR-39 chemical etching characteristics in NaOH and KOH solutions, comprising varied concentration and temperature. The bulk-etch rate and activation energy of the process were obtained. The critical energy and critical energy-loss rate of CR-39 track-detectors for registration of protons were experimentally determined. Samples were exposed to 24 Mev proton beams in the IEN/CNEN Cyclotron (CV-28), using scattering chamber with a tantalum thin target and aluminium absorbers in contact with the samples, in order to provide the required fluctuation in the scattered beam energy. From the mean track-diameter plotted against incident proton energy the critical energy was obtained. From the calculated energy-loss rate vs. energy curve, the critical energy loss rate were evaluated. The CR-39 response for low energy alpha particles (E = 7h) under the conditions of 6.25 N NaOH at 70 0 C. It is shown that successive chemical etchings do not produce the same track geometry as obtained by means of a continous revelation with the same total etching time. (Author) [pt

  11. Observation of anomalons in CR-39 track detectors

    International Nuclear Information System (INIS)

    Tincknell, M.L.; Price, P.B.

    1984-01-01

    The authors have observed fragments of 1.85 GeV/nucleon 40 Ar in CR-39 etched track detector and they find anomalously short mean free paths (mfp's) of secondary nuclei with 11 less than or equal to Z less than or equal to 17 in the first 2 cm after their production, at approx.3 standard deviations. This confirms previous reports of this anomalon effect in nuclear emulsion in a new detector with dissimilar potential systematic errors

  12. Optimization of some electrochemical etching parameters for cellulose derivatives

    International Nuclear Information System (INIS)

    Chowdhury, Annis; Gammage, R.B.

    1978-01-01

    Electrochemical etching of fast neutron induced recoil particle tracks in cellulose derivatives and other polymers provides an inexpensive and sensitive means of fast neutron personnel dosimetry. A study of the shape, clarity, and size of the tracks in Transilwrap polycarbonate indicated that the optimum normality of the potassium hydroxide etching solution is 9 N. Optimizations have also been attempted for cellulose nitrate, triacetate, and acetobutyrate with respect to such electrochemical etching parameters as frequency, voltage gradient, and concentration of the etching solution. The measurement of differential leakage currents between the undamaged and the neutron damaged foils aided in the selection of optimum frequencies. (author)

  13. Vacuum treatment of CR-39 for the reduction of background in neutron induced autoradiography of boron

    International Nuclear Information System (INIS)

    Freyer, K.; Treutler, H.C.; Dietze, K.; Hunyadi, I.; Csige, I.; Somogyi, G.

    1991-01-01

    The influence of etching time and vacuum processing before, during, and after neutron irradiation on the ''signal/noise'' ratio of the neutron induced autoradiography of boron using CR-39 track detectors has been investigated. The neutron irradiation was carried out in a vacuum chamber using the Cf-252 neutron source of the Central Institute of Isotope and Radiation Research at Leipzig. Hungarian-made CR-39 type track detectors, MA-ND/p and MA-ND/α, produced in different years, are compared. After a few hours of 2 kPa (about 10 -2 Torr) vacuum treatment, the ''signal/noise'' ratio for boron determination is improved remarkably in most cases of the detector and etching-time combinations used. (author)

  14. A parameterization of nuclear track profiles in CR-39 detector

    Science.gov (United States)

    Azooz, A. A.; Al-Nia'emi, S. H.; Al-Jubbori, M. A.

    2012-11-01

    In this work, the empirical parameterization describing the alpha particles’ track depth in CR-39 detectors is extended to describe longitudinal track profiles against etching time for protons and alpha particles. MATLAB based software is developed for this purpose. The software calculates and plots the depth, diameter, range, residual range, saturation time, and etch rate versus etching time. The software predictions are compared with other experimental data and with results of calculations using the original software, TRACK_TEST, developed for alpha track calculations. The software related to this work is freely downloadable and performs calculations for protons in addition to alpha particles. Program summary Program title: CR39 Catalog identifier: AENA_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AENA_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Copyright (c) 2011, Aasim Azooz Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met • Redistributions of source code must retain the above copyright, this list of conditions and the following disclaimer. • Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution This software is provided by the copyright holders and contributors “as is” and any express or implied warranties, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose are disclaimed. In no event shall the copyright owner or contributors be liable for any direct, indirect, incidental, special, exemplary, or consequential damages (including, but not limited to, procurement of substitute goods or services; loss of use, data, or profits; or business interruption) however caused and

  15. Development and application of the electrochemical etching technique. Annual progress report

    International Nuclear Information System (INIS)

    1979-08-01

    This report documents advances in the development and application of the electrochemical etching technique for thermal and epithermal neutron dosimetry as well as track geometry determinations. The bulk and track etching rates were studied by evaluating the track geometry during electrochemical etching. The foil surface removed versus etching time for two different etchants at 1000 V, 2 kHz, and 22 0 C were studied. Results indicated that the bulk etching rates were constant for the two etchants, i.e. 45% KOH and 45% KOH mixed with an equal volume of C 2 H 5 OH 5 and were equal to 0.20 +- 0.14 μm/hr and 2.7 +- 0.27 μm/hr from each side of the foil. The track etching rate (as contrasted with the bulk etching rate) can be determined by the microscope focus at various depths. The increase of track depth values as a function of etching time for the two etchants are plotted. The track cone angles were determined and found to be much larger for electrochemically etched polycarbonate foils than for most plastics etched with passive chemical techniques

  16. Impact of x-ray dose on track formation and data analysis for CR-39-based proton diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Rinderknecht, H. G., E-mail: rinderknecht1@llnl.gov; Rojas-Herrera, J.; Zylstra, A. B.; Frenje, J. A.; Gatu Johnson, M.; Sio, H.; Sinenian, N.; Rosenberg, M. J.; Li, C. K.; Séguin, F. H.; Petrasso, R. D. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Filkins, T.; Steidle, Jessica A.; Traynor, N.; Freeman, C. [State University of New York at Geneseo, Geneseo, New York 14454 (United States); Steidle, Jeffrey A. [Rochester Institute of Technology, Rochester, New York 14623 (United States)

    2015-12-15

    The nuclear track detector CR-39 is used extensively for charged particle diagnosis, in particular proton spectroscopy, at inertial confinement fusion facilities. These detectors can absorb x-ray doses from the experiments in the order of 1–100 Gy, the effects of which are not accounted for in the previous detector calibrations. X-ray dose absorbed in the CR-39 has previously been shown to affect the track size of alpha particles in the detector, primarily due to a measured reduction in the material bulk etch rate [Rojas-Herrera et al., Rev. Sci. Instrum. 86, 033501 (2015)]. Similar to the previous findings for alpha particles, protons with energies in the range 0.5–9.1 MeV are shown to produce tracks that are systematically smaller as a function of the absorbed x-ray dose in the CR-39. The reduction of track size due to x-ray dose is found to diminish with time between exposure and etching if the CR-39 is stored at ambient temperature, and complete recovery is observed after two weeks. The impact of this effect on the analysis of data from existing CR-39-based proton diagnostics on OMEGA and the National Ignition Facility is evaluated and best practices are proposed for cases in which the effect of x rays is significant.

  17. Impact of x-ray dose on track formation and data analysis for CR-39-based proton diagnostics

    International Nuclear Information System (INIS)

    Rinderknecht, H. G.; Rojas-Herrera, J.; Zylstra, A. B.; Frenje, J. A.; Gatu Johnson, M.; Sio, H.; Sinenian, N.; Rosenberg, M. J.; Li, C. K.; Séguin, F. H.; Petrasso, R. D.; Filkins, T.; Steidle, Jessica A.; Traynor, N.; Freeman, C.; Steidle, Jeffrey A.

    2015-01-01

    The nuclear track detector CR-39 is used extensively for charged particle diagnosis, in particular proton spectroscopy, at inertial confinement fusion facilities. These detectors can absorb x-ray doses from the experiments in the order of 1–100 Gy, the effects of which are not accounted for in the previous detector calibrations. X-ray dose absorbed in the CR-39 has previously been shown to affect the track size of alpha particles in the detector, primarily due to a measured reduction in the material bulk etch rate [Rojas-Herrera et al., Rev. Sci. Instrum. 86, 033501 (2015)]. Similar to the previous findings for alpha particles, protons with energies in the range 0.5–9.1 MeV are shown to produce tracks that are systematically smaller as a function of the absorbed x-ray dose in the CR-39. The reduction of track size due to x-ray dose is found to diminish with time between exposure and etching if the CR-39 is stored at ambient temperature, and complete recovery is observed after two weeks. The impact of this effect on the analysis of data from existing CR-39-based proton diagnostics on OMEGA and the National Ignition Facility is evaluated and best practices are proposed for cases in which the effect of x rays is significant

  18. Electrochemical etching of a niobium foil in methanolic HF for electrolytic capacitor

    International Nuclear Information System (INIS)

    Kim, Kyungmin; Park, Jiyoung; Cha, Gihoon; Yoo, Jeong Eun; Choi, Jinsub

    2013-01-01

    Electrochemical etching of niobium foil in order to enlarge the surface area for the application in electrolytic capacitor was carried out in a methanolic electrolyte. We found that the pit density and depth are not linearly proportional to concentration of HF and applied potential: there is the optimal concentration of HF at each applied potential. The optimal etching condition was obtained at 50 V in 0.99 vol.% HF, which exhibited the capacitance of 350 μF cm −2 . Pit density and depth of pits on electrochemical etched Nb foil under different conditions were counted from SEM images and electrochemical impedance spectroscopy (EIS) of the etched Nb foils was carried out for the capacitance measurement. Equivalent circuit model showing less than 5% error was suggested for applying to the etched niobium foil. - Highlights: • Surface enlargement of Nb foil can be achieved by electrochemical etching in methanolic HF. • Electrolytic capacitor of etched niobium foil exhibits a capacitance of 350 μF cm −2 . • The method provides a way of developing commercially viable process

  19. Vacuum treatment of CR-39 for the reduction of background in neutron induced autoradiography of boron

    Energy Technology Data Exchange (ETDEWEB)

    Freyer, K.; Treutler, H.C.; Dietze, K. (Central Inst. of Isotope and Radiation Research, Leipzig (Germany, F.R.)); Hunyadi, I.; Csige, I.; Somogyi, G. (Magyar Tudomanyos Akademia, Debrecen (Hungary). Atommag Kutato Intezete)

    1991-01-01

    The influence of etching time and vacuum processing before, during, and after neutron irradiation on the ''signal/noise'' ratio of the neutron induced autoradiography of boron using CR-39 track detectors has been investigated. The neutron irradiation was carried out in a vacuum chamber using the Cf-252 neutron source of the Central Institute of Isotope and Radiation Research at Leipzig. Hungarian-made CR-39 type track detectors, MA-ND/p and MA-ND/{alpha}, produced in different years, are compared. After a few hours of 2 kPa (about 10{sup -2} Torr) vacuum treatment, the ''signal/noise'' ratio for boron determination is improved remarkably in most cases of the detector and etching-time combinations used. (author).

  20. Study of projectile fragmentation in the reaction (158 A GeV) Pb + Pb using CR-39

    CERN Document Server

    Qureshi, I E; Javed, M T; Manzoor, S; Sher, G; Aleem, F; Khan, H A

    2005-01-01

    The fragmentation of Pb ions at 158 A GeV energy produced in the interaction with Pb target has been studied using a CR-39 track detector. A stack comprising of 64 detectors was prepared such that a target of 1 cm thickness was sandwiched between the sheets of CR-39. The purpose of this exposure geometry was to calibrate CR-39 with respect to relativistic heavy ions as well as to study the fragmentation of Pb ions at 158 A GeV energy. The exposure was carried out at the SPS beam facility of CERN at normal incidence with a fluence of . Two detectors from the exposed stack have been selected for this study: one before and the other after the target material. After etching, the detectors were scanned using an optical microscope and the etched track lengths and the diameters of the track openings were measured manually. Considering that the lengths of tracks provide the best charge resolution for Z>65, we have measured track lengths for a sufficiently large number of fragments to identify individual charge states...

  1. Fast neutron spectrometry based on proton detection in CR-39 detector

    Energy Technology Data Exchange (ETDEWEB)

    Dajko, G.; Somogyi, G.

    1986-01-01

    The authors have developed a home-made proton-sensitive CR-39 track detector called MA-ND/p. Using this and the n-p scattering process the performance of a fast neutron spectrometer has been studied by applying two different methods. These are based on track density determinations by using varying radiator thicknesses at constant etching time and by using varying etching times at fixed radiator thickness, respectively. For both methods studied a computer programme is made to calculate the theoretically expected neutron sensitivity as a function of neutron energy. For both methods the neutron sensitivities, expressed in terms of observable etched proton tracks per neutron, are determined experimentally for 3.3 and 14.7 MeV neutron energies. The theoretical and experimental data obtained are compared.

  2. Fast neutron spectrometry based on proton detection in CR-39 detector

    International Nuclear Information System (INIS)

    Dajko, G.; Somogyi, G.

    1986-01-01

    The authors have developed a home-made proton-sensitive CR-39 track detector called MA-ND/p. Using this and the n-p scattering process the performance of a fast neutron spectrometer has been studied by applying two different methods. These are based on track density determinations by using varying radiator thicknesses at constant etching time and by using varying etching times at fixed radiator thickness, respectively. For both methods studied a computer programme is made to calculate the theoretically expected neutron sensitivity as a function of neutron energy. For both methods the neutron sensitivities, expressed in terms of observable etched proton tracks per neutron, are determined experimentally for 3.3 and 14.7 MeV neutron energies. The theoretical and experimental data obtained are compared. (author)

  3. Future developments in etched track detectors for neutron dosimetry

    International Nuclear Information System (INIS)

    Tommasino, L.

    1987-01-01

    Many laboratories engaged in the field of personal neutron dosimetry are interested in developing better etching processes and improving the CR-39 detecting materials. To know how much effort must still be devoted to the development of etch track dosimetry, it is necessary to understand the advantages. limitations and degree of exploitation of the currently available techniques. So much has been learned about the chemical and electrochemical etching processes that an optimised combination of etching processes could make possible the elimination of many of the existing shortcomings. Limitations of etched track detectors for neutron dosimetry arise mainly because the registration occurs only on the detector surface. These damage type detectors are based on radiation induced chain scission processes in polymers, which result in hole-type tracks in solids. The converse approach, yet to be discovered, would be the development of cure-track detectors, where radiation induced cross linking between organic polymer chains could result in solid tracks in liquids. (author)

  4. Pershore made CR-39(DOP) as a 1.015 GeV/n 197Au-ion detector

    International Nuclear Information System (INIS)

    Bhattacharyya, D.P.; Chakrabarty, S.; Rakshit, R.; Basu, B.; Pal, P.; Biswas, S.

    1993-01-01

    Pershore made CR-39(DOP) stack was exposed at a zenith angle of 30deg by 197 Au-ions of energy 1.015 GeV/n using LBL BEVALAC beam. The top of the irradiated plate of the stack has been etched in 6.25N NaOH solution at 70degC for one hour. About 1202 cone lengths were optically measured. The estimated etch rate ratio of the incident 197 Au projectile beam in CR-39 has been found to be 27±2. The result has been compared with earlier observation. The charge resolution of the detector has been estimated from the average of double cone lengths and has been found to have a value of (0.58±0.03)e for 197 Au-ions. (orig.)

  5. Empirical assessment of the detection efficiency of CR-39 at high proton fluence and a compact, proton detector for high-fluence applications

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, M. J., E-mail: mrosenbe@mit.edu; Séguin, F. H.; Waugh, C. J.; Rinderknecht, H. G.; Orozco, D.; Frenje, J. A.; Johnson, M. Gatu; Sio, H.; Zylstra, A. B.; Sinenian, N.; Li, C. K.; Petrasso, R. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Glebov, V. Yu.; Stoeckl, C.; Hohenberger, M.; Sangster, T. C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); LePape, S.; Mackinnon, A. J.; Bionta, R. M.; Landen, O. L. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); and others

    2014-04-15

    CR-39 solid-state nuclear track detectors are widely used in physics and in many inertial confinement fusion (ICF) experiments, and under ideal conditions these detectors have 100% detection efficiency for ∼0.5–8 MeV protons. When the fluence of incident particles becomes too high, overlap of particle tracks leads to under-counting at typical processing conditions (5 h etch in 6N NaOH at 80 °C). Short etch times required to avoid overlap can cause under-counting as well, as tracks are not fully developed. Experiments have determined the minimum etch times for 100% detection of 1.7–4.3-MeV protons and established that for 2.4-MeV protons, relevant for detection of DD protons, the maximum fluence that can be detected using normal processing techniques is ≲3 × 10{sup 6} cm{sup −2}. A CR-39-based proton detector has been developed to mitigate issues related to high particle fluences on ICF facilities. Using a pinhole and scattering foil several mm in front of the CR-39, proton fluences at the CR-39 are reduced by more than a factor of ∼50, increasing the operating yield upper limit by a comparable amount.

  6. Response of LR-115 type II and CR-39 plastic track detectors to Am-Be and 14.1-MeV neutrons

    International Nuclear Information System (INIS)

    Bradley, D.A.; Chong, C.S.; Saat, Ahmat; Sidik, A.G.; Ghose, A.M.

    1987-01-01

    The fast-neutron response of the plastic LR-115 type II and CR-39 track detectors have been compared, using a 14.1-MeV neutron generator and a radionuclide Am-Be neutron source (effective primary neutron energy 4.5-MeV). The distribution of track diameters for a range of etching times has been evaluated, taking into account track registration efficiency and the relevant fast neutron scattering cross-sections. The efficiency of etched-track formation in LR-115 type II due to neutron irradiation is approximately double that in CR-39. The 14.1-MeV neutrons also tend to produce tracks in both materials with somewhat greater efficiency than do the lower energy neutrons from the radionuclide source, for a given etching time. (author)

  7. Response of CR-39 based personnel neutron dosemeter in terms of directional dose equivalent, in free air and on phantom

    International Nuclear Information System (INIS)

    Pal, Rupali R.; Sathian, Deepa; Jayalakshmi, V.; Chougaonkar, M.P.

    2011-01-01

    CR-39 is the most sensitive of nuclear track detectors for protons and is recommended as an effective neutron dosimeter because of it's low threshold energy of 100 keV neutrons. The fraction of protons that gives detectable tracks in CR-39 depends on the energy of the proton angle of incidence and etching conditions. As a consequence the registration efficiency of neutrons in the CR-39 plastics used for neutron personnel monitoring is strongly influenced by the direction of radiation incidence. This paper presents the relative response of CR-39 at varying neutron incident angles, for 241 Am-Be neutron source spectra in free air and on ISO phantom, in terms of operational quantities. It is observed that the angular dependence of CR-39 for irradiations in air and on phantom is essentially the same indicating that the phantom does not affect the directional response of CR-39. (author)

  8. Is CR39 worth the effort?

    International Nuclear Information System (INIS)

    Griffith, R.V.

    1987-01-01

    CR39 proton sensitive track detectors were greeted by the radiation protection community at the end of the last decade as a major breakthrough for personnel neutron dosimetry. A number of laboratories eagerly began research on application of CR39 to their dosimetry needs. However, in the last two or three years the enthusiasm has subsided, and many health physicists have stopped working with the material. The number of participants using CR39 in the Oak Ridge National Laboratory Personnel Intercomparison Studies dropped from six in 1985 to three in 1986. On a national level, the Federal Republic of Germany with researchers active in CR39 research recently adopted an albedo system as their national standard. In contrast, the United States Department of Energy (DOE) is supporting development of a CR39 based combination dosimeter to meet Department wide dosimetry needs. The English National Radiological Protection Board (NRPB) now features the use of CR39 in the NRPB PADC(CR39). There has obviously been a range of experiences with CR39 in the dosimetry community. Why has this been the case, and what is the proper role for CR39 in personnel neutron dosimetry. 12 refs., 2 figs., 1 tab

  9. Advances in the development of Cr-39 based neutron dosimeters

    International Nuclear Information System (INIS)

    Hadlock, D.E.; Parkhurst, M.A.

    1987-12-01

    A combination thermoluminescent dosimeter (TLD) and track etch dosimeter (TED), which can be used for detecting neutrons over a wide energy range, has been developed through recent research in passive neutron dosimetery. This dosimeter uses Li-600 TLDs to detect thermal and low energy neutrons reflected from the body, and the TED polymer of CR-39, to detect fast neutrons from proton recoil interactions with the polyethylene radiator or with CR-39 itself. Some form of the combination dosimeter is currently in use at several US Department of Energy (DOE) facilities, and its use is expected to expand over the next year to include all DOE facilities where significant neutron exposures may occur. The extensive research conducted on the TED component over the past six years has continually focused on material improvements, reduction in processing time and dosimeter handling, and ease of sample readout with the goal of automating the process as much as possible. 1 fig

  10. Impact of x-ray dose on the response of CR-39 to 1-5.5 MeV alphas

    International Nuclear Information System (INIS)

    Rojas-Herrera, J.; Rinderknecht, H. G.; Zylstra, A. B.; Gatu Johnson, M.; Orozco, D.; Rosenberg, M. J.; Sio, H.; Seguin, F. H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D.

    2015-01-01

    The CR-39 nuclear track detector is used in many nuclear diagnostics fielded at inertial confinement fusion (ICF) facilities. Large x-ray uences generated by ICF experiments may impact the CR-39 response to incident charged particles. To determine the impact of x-ray exposure on the CR-39 response to alpha particles, a thick-target bremsstrahlung x-ray generator was used to expose CR-39 to various doses of 8 keV Cu-K α and K β x-rays. The CR-39 detectors were then exposed to 1-5.5 MeV alphas from an Am-241 source. The regions of the CR-39 exposed to x-rays showed a smaller track diameter than those not exposed to x-rays: for example, a dose of 3.0 ± 0.1 Gy causes a decrease of (19 ± 2)% in the track diameter of a 5.5 MeV alpha particle, while a dose of 60.0 ± 1.3 Gy results in a decrease of (45 ± 5)% in the track diameter. The reduced track diameters were found to be predominantly caused by a comparable reduction in the bulk etch rate of the CR-39 with x-ray dose. A residual effect depending on alpha particle energy is characterized using an empirical formula

  11. Change in the sensitivity of CR-39 for alpha-tracks after the storage at different temperatures

    International Nuclear Information System (INIS)

    Enomoto, Hiroko; Ishigure, Nobuhito

    2000-01-01

    The effect of storage on track registration property of CR-39 has been investigated. Pieces of CR-39 plate were irradiated with normally incident α-particles and fission fragments using a 252 Cf source prior and posterior to the storage of them in air for one year at different temperatures of -80degC, -23degC, 4degC, 23degC and 35degC. Periodical etching was performed for the pieces stored at different temperatures using the solution of NaOH with 7 mol+l -1 at 70degC for 4 hours. Bulk etch rate (V b ) was obtained from the etch pit diameter (D f ) of fission tracks using the equation: V b =D f /(2t), where t is etching time (h). The sensitivity for α-tracks (S) was obtained from the ratio of the etch pit diameters between α-tracks (D a ) and fission-tracks using the equation: S={1+(D a /D f ) 2 }/{1-(D a /D f ) 2 }-1. The present results show that both the bulk etch rate and α-track sensitivity are not constant, which tend to decrease with storage times and storage temperatures. At -80degC, -23degC and 4degC the change in the sensitivity was negligible. On the other hand, the storage at 23degC for 1 year decreased the sensitivity down to 74%. The most significant effect was observed on the α-track sensitivity at 35degC, which was reduced to 80% for one month, 61% for three months, 42% for six months and 32% for one year. By the comparison of experiments between fading and ageing it is shown that such storage effect is attributed not to fading of latent tracks but mainly to some changes in the detector itself. When CR-39 is used of radon monitoring or neutron monitoring, the following points should be paid attention to: (1) the detector should be stored in a refrigerator before exposure and until etching after the exposure, (2) the change in the sensitivity between the time of calibration and the time of use should be evaluated and the counting efficiency at the measurement should be corrected and (3) for comparison or for interpretation of experimental results

  12. Response of CR39 detector to 5 A GeV Si14+ ions and measurement of total charge changing cross-section

    International Nuclear Information System (INIS)

    Gupta, Renu; Kumar, Ashavani

    2013-01-01

    In the present work, response of CR39 track etch detector was obtained by cone-height measurement technique. CR39 track etch detector was used to identify the incident charged particles and their fragments by the measurements of cone-height of tracks using an optical microscope DM6000 M and automated image analyzer system installed with Leica QWin Plus software. The CR39 detector was calibrated and the response points were fitted with a linear relation and all the points are within the limits of the experimental errors. The charge resolution of the detector was calculated to be 0.2e. The response function is obtained and fitted with a linear relation which is good throughout Z/β=6.1–14.1. The experimental value of the total charge changing cross-section of 5 A GeV Si 14+ ion beam in polyethylene and CR39 combined target is σ tot =(734±128) mb. The total charge changing cross-section is compared with the experimental results of others based on cone base-area measurement technique and also fitted by the Bradt–Peters geometrical cross-section. - Highlights: • Charge resolution of 0.2e was obtained by cone-height measurement. • Consistency in manual measurements of cone-heights is presented. • Response of CR39 detector was obtained and fitted with first degree polynomial. • Total charge changing cross-section of 5 A GeV Si 14+ ions in CH 2 and CR39 as a combined target was calculated

  13. Alpha-particle autoradiography in CR-39: a technique for quantitative assessment of alpha-emitters in biological tissue

    International Nuclear Information System (INIS)

    Fews, A.P.; Henshaw, D.L.

    1983-01-01

    The techniques for α-particle autoradiography based on the plastic nuclear track detector CR-39, previously reported, have been developed considerably. The techniques are applied to α-autoradiography of human lung tissue in particular but are applicable to any biological tissue. The most important developments are: (i) Improvements in the manufacture and pre-etching of the plastic. (ii) High resolution α-particle spectroscopy in CR-39 plastic based on the analysis of the structure of the etched track. (iii) Calculation of the effective thickness of tissue sampled by the plastic. (iv) A deconvolution analysis which takes the distributions of track length and dip angle in the plastic and determines the α-particle range spectrum and distribution of tissue activity with height above the plastic surface. (v) The analysis of radon diffusion in tissue to determine the mean radon diffusion distance in tissue and plastic. (author)

  14. Optical and structural properties of porous zinc oxide fabricated via electrochemical etching method

    International Nuclear Information System (INIS)

    Ching, C.G.; Lee, S.C.; Ooi, P.K.; Ng, S.S.; Hassan, Z.; Hassan, H. Abu; Abdullah, M.J.

    2013-01-01

    Highlights: • Hillock like porous structure zinc oxide was obtained via electrochemical etching. • Anisotropic dominance etching process by KOH etchant. • Reststrahlen features are sensitive to multilayer porous structure. • Determination of porosity from IR reflectance spectrum. -- Abstract: We investigated the optical and structural properties of porous zinc oxide (ZnO) thin film fabricated by ultraviolet light-assisted electrochemical etching. This fabrication process used 10 wt% potassium hydroxide solution as an electrolyte. Hillock-like porous ZnO films were successfully fabricated according to the field emission scanning electron microscopy results. The cross-sectional study of the sample indicated that anisotropic-dominated etching process occurred. However, the atomic force microscopic results showed an increase in surface roughness of the sample after electrochemical etching. A resonance hump induced by the porous structure was observed in the infrared reflectance spectrum. Using theoretical modeling technique, ZnO porosification was verified, and the porosity of the sample was determined

  15. Some characteristics of the CR-39 solid state nuclear-track detector for protons and low energy alpha particles

    International Nuclear Information System (INIS)

    Fonseca, E.S. da.

    1983-01-01

    Experimental results related to certain registration properties of the CR-39 solid state nuclear-track detector for charged particles are presented and discussed. The determination of the CR-39 chemical etching in NaOH and KOH solutions, comprising concentration (2-10N) and temperature effects (50-90 0 C), showed the existence of an inverse proportion between the induction time and the temperature as well as the normal concentration of the solutions. The critical energy and the critical energy-loss rate of CR-39 track detectors for registration of protons were experimentally determined. A number of samples was exposed to 24MeV proton beams in the IEN-CNEN Cyclotron (CV-28), using a scattering chamber with a tantalum thin target and aluminium absorbers in contact with the samples in order to provide the required fluctuation in the scattered beam energy. From the mean track-diameter plotted against incident proton energy for 16h and 24h chemical etching (6.25 NaOH, 70 0 C), and considering 1.5 μm as the minimum observable track-diameter, the values (21.0 + - 1.5) MeV and (22.5 + - 1.5) MeV were deduced, respectively, for the critical energy. From the calculated energy-loss rate versus energy curve, the critical energy-loss rate was evaluated as 24 + - 2 MeV.cm 2 /g. Finally, the CR-39 response for low energy alpha particles (E [pt

  16. ECE laboratory in the Vinca Institute - its basic characteristics and fundamentals of electrochemical etching on polycarbonate

    International Nuclear Information System (INIS)

    Zunic, Z.S.; Ujic, P.; Celikovic, I.; Fujimoto, K.

    2003-01-01

    This paper deals with the introductory aspects of the Electrochemical Etching Laboratory installed at the VINCA Institute in the year 2003. The main purpose of the laboratory is its field application for radon and thoron large-scale survey using passive radon/thoron UFO type detectors. Since the etching techniques together with the laboratory equipment were transferred from the National Institute of Radiological Sciences, Chiba, Japan, it was necessary for both etching conditions to be confirmed and to be checked up, i. e., bulk etching speeds of chemical etching and electrochemical etching in the VINCA Electrochemical Etching Laboratory itself. Beside this initial step, other concerns were taken into consideration in this preliminary experimental phase such as the following: the measurable energy range of the polycarbonate film, background etch pit density of the film and its standard deviation and reproducibility of the response to alpha particles for different sets of etchings. (author)

  17. Response of CR-39 Detector Against Fast Neutron Using D-Polyethylene and H-Polyethylene Radiator

    International Nuclear Information System (INIS)

    Sofyan, Hasnel

    1996-01-01

    The research on the response of detector CR-39 by using D-Polyethylene and H-Polyethylene radiator has been carried out. The optimum number of nuclear tracks was found with the use of 30 % NaOH at 80 + 0,5oC for 80 minutes of etching time. The comparison of CR-39 detector response caused by D-Polyethylene radiator against H-Polyethylene radiator of irradiation in air, were found to be 1.18 and 0.84 for 241Am-Be neutron source and neutron source from reactor respectively. For phantom irradiation, the results were found to be 1.75 for 241Am-Be neutron source, and 0.77 for neutron source from reactor

  18. A multi-step electrochemical etching process for a three-dimensional micro probe array

    International Nuclear Information System (INIS)

    Kim, Yoonji; Youn, Sechan; Cho, Young-Ho; Park, HoJoon; Chang, Byeung Gyu; Oh, Yong Soo

    2011-01-01

    We present a simple, fast, and cost-effective process for three-dimensional (3D) micro probe array fabrication using multi-step electrochemical metal foil etching. Compared to the previous electroplating (add-on) process, the present electrochemical (subtractive) process results in well-controlled material properties of the metallic microstructures. In the experimental study, we describe the single-step and multi-step electrochemical aluminum foil etching processes. In the single-step process, the depth etch rate and the bias etch rate of an aluminum foil have been measured as 1.50 ± 0.10 and 0.77 ± 0.03 µm min −1 , respectively. On the basis of the single-step process results, we have designed and performed the two-step electrochemical etching process for the 3D micro probe array fabrication. The fabricated 3D micro probe array shows the vertical and lateral fabrication errors of 15.5 ± 5.8% and 3.3 ± 0.9%, respectively, with the surface roughness of 37.4 ± 9.6 nm. The contact force and the contact resistance of the 3D micro probe array have been measured to be 24.30 ± 0.98 mN and 2.27 ± 0.11 Ω, respectively, for an overdrive of 49.12 ± 1.25 µm.

  19. Evidence of formation of trans-Fe nuclei in Fe+Al interactions at 1.88 GeV using Cr-39 (DOP) detector

    International Nuclear Information System (INIS)

    Ganguly, A.K.; Chaudhuri, Biva

    1991-01-01

    A wedge-shaped aluminium target was irradiated with 1.88 A GeV Fe beam to study various features of Fe+Al nucleus-nucleus interaction and their dependence on target thickness. The detector employed was a stack of CR-39 (DOP) and Lexan plastic nuclear track detectors which have a characteristically high charge resolution property. To distinguish the actual events from background and buildup a selection criteria for easy and unambiguous rejection of unwanted interfering events the stack of detectors was placed at an angle of 60deg with respect to the beam. After irradiation the CR-39 (DOP) detectors were etched and the elliptic etch-pit diameters were scanned. The diameter distribution of the elliptic etch-pits exhibits the existence of trans Fe nuclei. The production of trans Fe fraction is seen to increase with the thickness of the aluminium target. The possible causes of this increase are being investigated. (author). 12 refs., 4 figs

  20. Organization of silicon nanocrystals by localized electrochemical etching

    International Nuclear Information System (INIS)

    Ayari-Kanoun, Asma; Drouin, Dominique; Beauvais, Jacques; Lysenko, Vladimir; Nychyporuk, Tetyana; Souifi, Abdelkader

    2009-01-01

    An approach to form a monolayer of organized silicon nanocrystals on a monocrystalline Si wafer is reported. Ordered arrays of nanoholes in a silicon nitride layer were obtained by combining electron beam lithography and plasma etching. Then, a short electrochemical etching current pulse led to formation of a single Si nanocrystal per each nanohole. As a result, high quality silicon nanocrystal arrays were formed with well controlled and reproducible morphologies. In future, this approach can be used to fabricate single electron devices.

  1. Exposure of CR39 Stacks to Oxygen and Sulphur Beams at the CERN-SPS

    CERN Multimedia

    2002-01-01

    We plan to expose 8 stacks of CR39 sheets to oxygen and sulphur ions of 60 and 200~GeV at the CERN-SPS.\\\\ \\\\ The main purpose of the exposures is the calibration of the CR39 sheets used for a large area experimental search for magnetic monopoles at the Gran Sasso Laboratory (experiment MACRO). \\\\ \\\\ The stacks have 20~layers of CR39, each layer 13~cm~x~7~cm and 1.4~mm thick. A copper absorber is located after the first 6 layers. \\\\ \\\\ We require exposures of about 2000 tracks per cm$^2$ over the entire area of the stack with a uniform illumination. The standard beam used for the emulsion experiments is normally adequate for this purpose.\\\\ \\\\ We have performed one exposure to sulphur ions. The etched tracks have been measured automatically with the Elbeck image analyser system. We measured the incoming sulphur ions as well as the nuclear fragments produced in the copper absorber. Clean separation among the peaks due to the various fragments is obtained (there is no indication of nuclei with fractional electri...

  2. The effect of solarradiation and UV photons on the CR-39 nuclear track detector

    International Nuclear Information System (INIS)

    Saad, A.F.

    2003-01-01

    The effects induced in the CR-39 polymer detector by total solar radiation (TSR) and UV photons were investigated. Thr exposure of detector samples to solar photons was carried out according to certain conditions. The TSR exposure period started in the middle of july and lasted unitel 12 th of september. 2000: the hottest months in zagazig, egypt. Another set of detector samples was exposed to UV photons from a UV lamp for different intervals. After UV exposure, these detectors were analysed with an FT-IR sepectrometer of jasco type 5300 in transmission mode. The FT-IR spectra does not show any considerable modifications due to UV irradiation in that detector. The effects of UV light were compared with those of solar radiation containing ultraviolet photons , on the registration properties of this polymer detector. Preliminaryresults revealed a proportionate increase in bluk etch rate of CR-39 detector with the increase of exposure time to the solar radiation. The results indicated that the CR-39 polymer detector can be used as a solar radiation dosimeter

  3. Metallographic examination of TD-nickel base alloys. [thermal and chemical etching technique evaluation

    Science.gov (United States)

    Kane, R. D.; Petrovic, J. J.; Ebert, L. J.

    1975-01-01

    Techniques are evaluated for chemical, electrochemical, and thermal etching of thoria dispersed (TD) nickel alloys. An electrochemical etch is described which yielded good results only for large grain sizes of TD-nickel. Two types of thermal etches are assessed for TD-nickel: an oxidation etch and vacuum annealing of a polished specimen to produce an etch. It is shown that the first etch was somewhat dependent on sample orientation with respect to the processing direction, the second technique was not sensitive to specimen orientation or grain size, and neither method appear to alter the innate grain structure when the materials were fully annealed prior to etching. An electrochemical etch is described which was used to observe the microstructures in TD-NiCr, and a thermal-oxidation etch is shown to produce better detail of grain boundaries and to have excellent etching behavior over the entire range of grain sizes of the sample.

  4. Impact of x-ray dose on the response of CR-39 to 1–5.5 MeV alphas

    Energy Technology Data Exchange (ETDEWEB)

    Rojas-Herrera, J., E-mail: jimmy06@mit.edu; Rinderknecht, H. G.; Zylstra, A. B.; Gatu Johnson, M.; Orozco, D.; Rosenberg, M. J.; Sio, H.; Seguin, F. H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2015-03-15

    The CR-39 nuclear track detector is used in many nuclear diagnostics fielded at inertial confinement fusion (ICF) facilities. Large x-ray fluences generated by ICF experiments may impact the CR-39 response to incident charged particles. To determine the impact of x-ray exposure on the CR-39 response to alpha particles, a thick-target bremsstrahlung x-ray generator was used to expose CR-39 to various doses of 8 keV Cu-K{sub α} and K{sub β} x-rays. The CR-39 detectors were then exposed to 1–5.5 MeV alphas from an Am-241 source. The regions of the CR-39 exposed to x-rays showed a smaller track diameter than those not exposed to x-rays: for example, a dose of 3.0 ± 0.1 Gy causes a decrease of (19 ± 2)% in the track diameter of a 5.5 MeV alpha particle, while a dose of 60.0 ± 1.3 Gy results in a decrease of (45 ± 5)% in the track diameter. The reduced track diameters were found to be predominantly caused by a comparable reduction in the bulk etch rate of the CR-39 with x-ray dose. A residual effect depending on alpha particle energy is characterized using an empirical formula.

  5. Triton, deuteron and proton responses of the CR-39 track detector

    Energy Technology Data Exchange (ETDEWEB)

    Yamauchi, Tomoya; Matsumoto, Hiroyoshi; Oda, Keiji [Kobe Univ. of Mercantile Marine (Japan)

    1996-07-01

    In the present study, we assessed the response of the CR-39 detector to proton, deuteron and triton from their etch-pit growth curves obtained by multi-step etching technique and the difference among their track registration properties was discussed. In order to avoid incorrect evaluation due to the missing track effect, particle irradiation was performed at various incident energies. The response function, S(R), etch rate ratio, S, as a function of the residual range, R, was experimentally evaluated for all hydrogen isotopes by this method. In the next, we obtained another form of response functions of S(E), S({beta}) and S(LET{sub 200}), which were presented as functions of the particle energy, E, the particle velocity, {beta}(=v/c), and the linear energy transfer in the case where the cut-off energy is 200 eV, LET{sub 200}, respectively. These information will be useful also in understanding the fundamentals of the latent track formation mechanism in the plastic track detectors. (J.P.N.)

  6. Proton Radiography with CR-39 by Using the Protons from High Power Femto-second Laser System

    International Nuclear Information System (INIS)

    Choi, Chang Il; Lee, Dong Hoon; Kang, Byoung Hwi; Kim, Yong Kyun; Choi, Il Woo; Ko, Do Kyeong; Lee, Jong Min

    2008-01-01

    Proton radiography techniques are useful to obtain a high quality image of a thin object, because protons travel straight in matter. Generation of the high energy proton using conventional accelerator costs high and requires large accelerating facility. But proton radiography using high power femto-second(10-15 second) laser has been interested, because it can generate high energy protons at lower price than the conventional accelerator like a cyclotron. For this study, we used the CR-39 SSNTD (Solid State Nuclear Track Detector) as the proton radiography screen. Commonly, CR-39 is used to detect the tracks of energetic charged particles. Incident energetic charged particles left latent tracks in the CR-39, in the form of broken molecular chains and free radicals. These latent tracks show high chemical reactivity. After chemical etching with the caustic alkali solution such as NaOH or KOH, tracks are appeared to forms of hole. If protons with various energies enter the two targets with another thickness, number of protons passed through the target per unit area is different each other. Using this feature of protons, we can a proton radiographic image with CR-39. We studied proton radiography with CR-39 by using energetic protons from high power femto-second laser and evaluated potentiality of femto-second laser as new energetic proton generator for radiography

  7. Quadrilateral Micro-Hole Array Machining on Invar Thin Film: Wet Etching and Electrochemical Fusion Machining

    Directory of Open Access Journals (Sweden)

    Woong-Kirl Choi

    2018-01-01

    Full Text Available Ultra-precision products which contain a micro-hole array have recently shown remarkable demand growth in many fields, especially in the semiconductor and display industries. Photoresist etching and electrochemical machining are widely known as precision methods for machining micro-holes with no residual stress and lower surface roughness on the fabricated products. The Invar shadow masks used for organic light-emitting diodes (OLEDs contain numerous micro-holes and are currently machined by a photoresist etching method. However, this method has several problems, such as uncontrollable hole machining accuracy, non-etched areas, and overcutting. To solve these problems, a machining method that combines photoresist etching and electrochemical machining can be applied. In this study, negative photoresist with a quadrilateral hole array pattern was dry coated onto 30-µm-thick Invar thin film, and then exposure and development were carried out. After that, photoresist single-side wet etching and a fusion method of wet etching-electrochemical machining were used to machine micro-holes on the Invar. The hole machining geometry, surface quality, and overcutting characteristics of the methods were studied. Wet etching and electrochemical fusion machining can improve the accuracy and surface quality. The overcutting phenomenon can also be controlled by the fusion machining. Experimental results show that the proposed method is promising for the fabrication of Invar film shadow masks.

  8. Evaluation of different polymers for fast neutron personnel dosimetry using electrochemical etching

    International Nuclear Information System (INIS)

    Gammage, R.B.; Cotter, S.J.

    1977-01-01

    There is considerable optimism for the enhancement by electrochemical etching of fast neutron-induced recoil tracks in polycarbonate for the purpose of personnel dosimetry. The threshold energy, however, is rather high. A desirable improvement would be to lower this energy below 1 MeV. With this objective in mind, we have commenced an investigation of cellulose acetate, triacetate, and acetobutyrate in addition to polycarbonate. These cellulose derivatives are chemically more reactive and physically weaker than polycarbonate. It might, therefore, be possible to initiate the electrochemical amplification at the sites of shorter recoil atom damage tracks than is possible with polycarbonate. Some characteristics important for electrochemically etching in aqueous electrolytes are listed. Chemical etching is combined with treeing, an electrical breakdown process that starts when the dielectric strength is exceeded. These mechanical and electrical properties pertain to the dry plastics. The absorption of water molecules and electrolyte ions will cause these values to be reduced. Results and conclusions of the study are presented

  9. Energy dependence of fast neutron dosimetry using electrochemical etching

    International Nuclear Information System (INIS)

    Su, S.J.; Morgan, K.Z.

    1978-01-01

    Registration of fast-neutron induced recoil tracks by the electrochemical etching technique as applied to sensitive Lexan polycarbonate foils provides a simple and inexpensive means of fast neutron personnel dosimetry. The sensitivity (tracks/neutron) of recoil particle registration is given as a function of neutron energy. Neutrons of 7 Li (p,n) 7 Be, 3 T (d,n) 4 He and 9 B, respectively. Results are compared with other studies using other neutron sources and conventional etching method

  10. Present status of fast neutron personnel dosimetry system based on CR-39 solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Pal, Rupali; Sathian, Deepa; Jayalakshmi, V.; Bakshi, A.K.; Chougaonkar, M.P.; Mayya, Y.S.; Kumar, Valli; Babu, Rajesh; Kar, S.; Joshi, V.M.

    2011-08-01

    Neutron sources are of different types depending upon the method of production such as nuclear reactors, particle accelerators and laboratory sources. Neutron sources depending upon their energy, flux, size etc. are used for variety of applications in basic and applied sciences, neutron scattering experiments and in industry such as oil well - digging, coal mining and processing, ore processing etc. Personnel working in nuclear installations such as reactors, accelerators, spent fuel processing plants, nuclear fuel cycle operations and those working in various industries such as oil refining, oil well-digging, coal mining and processing, ore processing, etc. need to be monitored for neutron exposures, if any. Neutron monitoring is especially necessary in view of the fact that the radiation weighting factor for neutron is much higher than gamma rays and also it varies with energy. Radiological Physics and Advisory Division is involved in monitoring of personnel working in neutron fields. Around 2100 workers from 70 institutions (DAE and Non-DAE) are monitored on a quarterly basis. Neutron personnel monitoring, carried out in the country is based on Solid State Nuclear Track Detection (SSNTD) technique. In this technique, neutrons interact with hydrogen in CR-39 polymer to produce recoil protons. These protons create damages in the polymer, which are enlarged and appear as tracks when subjected to electrochemical etching (ECE). These tracks are counted in an optical system to evaluate the neutron dose. The neutron dosimetry system based on SSNTD has undergone a significant development, since it was started in 1990. The development includes upgradation of image analysis system for counting tracks, introduction of chemical etching (CE) at elevated temperatures for evaluation of dose equivalents above 10 mSv and use of carbon laser for cutting of CR-39 detectors. The entire dose evaluation process has been standardized, which includes calibration and performance tests

  11. Factors affecting the response of the bubble detector BD-100 and a comparison of its response to CR-39

    International Nuclear Information System (INIS)

    Ipe, N.E.; Busick, D.D.; Pollock, R.W.

    1987-08-01

    The BD-100 is a bubble detector available commercially from Chalk River Nuclear Laboratories, Canada for neutron dosimetry. According to the manufacturer, the BD-100 detects neutrons over an energy range of 100 keV to 14 MeV and the dose equivalent response is independent of energy. The sensitivity of the detector is dependent upon its temperature at the time of irradiation. The sensitized detector self-nucleates upon sharp impact and when heated to temperatures of 48 0 C or greater. The BD-100 is insensitive to low energy gamma rays but responds to 6 MeV photons. The sensitivity (bubbles/μSv) of the BD-100 was found to be energy dependent when exposed to standard neutron sources with average energies ranging from 0.5 to 4.5 MeV. The bubbles formed upon irradiation continued to grow in size with time. The response of electrochemically etched CR-39 to the same neutron sources is also reported for comparison

  12. ECE laboratory in the Vinča institute: Its basic characteristics and fundamentals of electrochemic etching on polycarbonate

    Directory of Open Access Journals (Sweden)

    Žunić Zora S.

    2003-01-01

    Full Text Available This paper deals with the introductory aspects of the Electrochemical Etching Laboratory installed at the VINČA Institute in the year 2003. The main purpose of the laboratory is its field application for radon and thoron large-scale survey using passive radon/thoron UFO type detectors. Since the etching techniques together with the laboratory equipment were transferred from the National Institute of Radiological Sciences, Chiba, Japan, it was necessary for both etching conditions to be confirmed and to be checked up^ i. e., bulk etching speeds of chemical etching and electrochemical etching in the VINCA Electrochemical Etching Laboratory itself. Beside this initial step, other concerns were taken into consideration in this preliminary experimental phase such as the following: the measurable energy range of the polycarbonate film, background etch pit density of the film and its standard deviation and reproducibility of the response to alpha particles for different sets of etchings.

  13. Note: Electrochemical etching of cylindrical nanoprobes using a vibrating electrolyte

    International Nuclear Information System (INIS)

    Wang, Yufeng; Zeng, Yongbin; Qu, Ningsong; Zhu, Di

    2015-01-01

    An electrochemical etching process using a vibrating electrolyte of potassium hydroxide to prepare tungsten cylindrical nanotips is developed. The vibrating electrolyte eases the effects of a diffusion layer and extends the etching area, which aid in the production of cylindrical nanotips. Larger amplitudes and a vibration frequency of 35 Hz are recommended for producing cylindrical nanotips. Nanotips with a tip radius of approximately 43 nm and a conical angle of arctan 0.0216 are obtained

  14. Interaction mean free path measurements for relativistic heavy ion fragments using CR39 plastic track detectors

    International Nuclear Information System (INIS)

    Drechsel, H.; Brechtmann, C.; Dreute, J.; Sonntag, S.; Trakowski, W.; Beer, J.; Heinrich, W.

    1984-01-01

    This paper describes an experiment measuring the interaction mean free paths for charge changing nuclear collisions of relativistic heavy ion fragments. We use a stack of CR39 plastic nuclear track detectors that was irradiated with 1.8 GeV/nucleon 40 Ar ions at the Berkeley Bevalac. About 1.5 x 10 7 etch cones were measured in this experiment using an automatic measuring system. By tracing the etch cones over successive plastic foils the particle trajectories in the stack were reconstructed. For 14185 trajectories with 6444 nuclear collisions of fragments with charge 9-15 the interaction mean free path in the plastic was determined. (orig.)

  15. A Twice Electrochemical-Etching Method to Fabricate Superhydrophobic-Superhydrophilic Patterns for Biomimetic Fog Harvest.

    Science.gov (United States)

    Yang, Xiaolong; Song, Jinlong; Liu, Junkai; Liu, Xin; Jin, Zhuji

    2017-08-18

    Superhydrophobic-superhydrophilic patterned surfaces have attracted more and more attention due to their great potential applications in the fog harvest process. In this work, we developed a simple and universal electrochemical-etching method to fabricate the superhydrophobic-superhydrophilic patterned surface on metal superhydrophobic substrates. The anti-electrochemical corrosion property of superhydrophobic substrates and the dependence of electrochemical etching potential on the wettability of the fabricated dimples were investigated on Al samples. Results showed that high etching potential was beneficial for efficiently producing a uniform superhydrophilic dimple. Fabrication of long-term superhydrophilic dimples on the Al superhydrophobic substrate was achieved by combining the masked electrochemical etching and boiling-water immersion methods. A long-term wedge-shaped superhydrophilic dimple array was fabricated on a superhydrophobic surface. The fog harvest test showed that the surface with a wedge-shaped pattern array had high water collection efficiency. Condensing water on the pattern was easy to converge and depart due to the internal Laplace pressure gradient of the liquid and the contact angle hysteresis contrast on the surface. The Furmidge equation was applied to explain the droplet departing mechanism and to control the departing volume. The fabrication technique and research of the fog harvest process may guide the design of new water collection devices.

  16. Thermodynamics of nuclear track chemical etching

    Science.gov (United States)

    Rana, Mukhtar Ahmed

    2018-05-01

    This is a brief paper with new and useful scientific information on nuclear track chemical etching. Nuclear track etching is described here by using basic concepts of thermodynamics. Enthalpy, entropy and free energy parameters are considered for the nuclear track etching. The free energy of etching is determined using etching experiments of fission fragment tracks in CR-39. Relationship between the free energy and the etching temperature is explored and is found to be approximately linear. The above relationship is discussed. A simple enthalpy-entropy model of chemical etching is presented. Experimental and computational results presented here are of fundamental interest in nuclear track detection methodology.

  17. Electrochemical etching amplification of low-let recoil particle tracks in polymers for fast neutron dosimetry

    International Nuclear Information System (INIS)

    Sohrabi, M.; Morgan, K.Z.

    1975-11-01

    An electrochemical etching method for the amplification of fast-neutron-induced recoil particle tracks in polymers was investigated. The technique gave superior results over those obtained by conventional etching methods especially when polycarbonate foils were used for recoil particle track amplification. Electrochemical etching systems capable of multi-foil processing were designed and constructed to demonstrate the feasibility of the techniques for large-scale neutron dosimetry. Electrochemical etching parameters were studied including the nature or type of the polymer foil used, foil thickness and its effect on etching time, the applied voltage and its frequency, the chemical composition, concentration, and temperature of the etchant, distance and angle between the electrodes, and the type of particles such as recoil particles including protons. Recoil particle track density, mean track diameter, and optical density as functions of the mentioned parameters were determined. Each parameter was found to have a distinct effect on the etching results in terms of the measured responses. Several new characteristics of this fast neutron dosimetry method were studied especially for personnel dosimetry using various radiation sources such as nuclear reactors, medical cyclotrons, and isotopic neutron sources. The dose range, neutron energy dependence, directional response, fading characteristics, neutron threshold energy, etc. were investigated

  18. Enhanced optical performance of electrochemically etched porous silicon carbide

    International Nuclear Information System (INIS)

    Naderi, N; Hashim, M R; Saron, K M A; Rouhi, J

    2013-01-01

    Porous silicon carbide (PSC) was successfully synthesized via electrochemical etching of an n-type hexagonal silicon carbide (6H-SiC) substrate using various current densities. The cyclic voltammograms of SiC dissolution show that illumination is required for the accumulation of carriers at the surface, followed by surface oxidation and dissolution of the solid. The morphological and optical characterizations of PSC were reported. Scanning electron microscopy results demonstrated that the current density can be considered an important etching parameter that controls the porosity and uniformity of PSC; hence, it can be used to optimize the optical properties of the porous samples. (paper)

  19. Employment of the polycarbonates Makrofol-DE and CR-39 for neutron radiography

    International Nuclear Information System (INIS)

    Pereira, Marco Antonio Stanojev

    2000-01-01

    The track-etch method was employed for Neutron Radiography purposes. The solid state nuclear track detectors Makrofol-DE and CR-39 together with a natural boron converter screen have been used as imaging systems. In order to determine their radiographic characteristics, the imaging systems were irradiated up to neutron exposures around 6x10 10 /cm 2 in a radiography facility installed at the IEA-R1 Nuclear Research Reactor and the detectors developed between 2 and 65 minutes. The main goal of this work was determine the radiography conditions for which the best contrast and resolution are obtained at the image. These conditions are: - Makrofol-DE: neutron exposure between 2x10 9 n/cm 2 and 2x10 10 n/cm 2 and developing time 6 minutes; CR-39: neutron exposure between 3x10 9 n/cm 2 and 2x10 10 n/cm 2 and developing time 25 minutes. The present results were compared with those ones determined to other track detectors, and discussed according to the theory of the image formation in solid state nuclear track detectors based on the optical properties of a single track. (author)

  20. LET calibration for CR-39 detectors in different oxygen environments

    International Nuclear Information System (INIS)

    Zhou, D.; Semones, E.; Weyland, M.; Benton, E.R.

    2007-01-01

    High LET (linear energy transfer) radiation is the main contributor to the radiation field in low Earth orbit (LEO) in terms of dose equivalent. CR-39 plastic nuclear track detectors (PNTDs) can measure the LET spectrum and charge spectrum for the complicated radiation field in space. Previous research indicated that the sensitivity of CR-39 is different for CR-39 PNTDs working in different oxygen environments. LET calibration for CR-39 detectors in different oxygen environments is needed. Almost all the previous LET calibration work was carried out for CR-39 detectors in good-oxygen condition, LET calibration work for CR-39 in poor-oxygen condition has not been conducted until our work. Systematic LET calibrations were carried out by JSC-SRAG (Space Radiation Analysis Group) for CR-39 detectors working in different oxygen environments and abundant results of LET calibrations were obtained. This paper introduces the method for CR-39 LET calibration, presents and discusses the calibration results and some applications

  1. A study of CR-39 track response to charged particles from NOVA implosions

    International Nuclear Information System (INIS)

    Phillips, T.W.; Cable, M.D.; Hicks, D.G.; Li, C.K.; Petrasso, R.D.; Seguin, F.H.

    1996-01-01

    We have exposed CR-39 track recording material to a number of NOVA implosions. Radiation from the implosion passed through an array of ranging filters, which aided identification of the incident particles and their energies. The etching procedure was calibrated by including a piece of track exposed to DD protons from a small accelerator. For the same shots, we quantitatively compare the DD neutron yield with the DD proton yield determined from the track. In DT implosions, tracks produced by neutron interactions prevent observation of charged-particle tracks that are produced by the processes of knock-on, secondary or tertiary fusion

  2. Method of plastic track detector electrochemical etching

    International Nuclear Information System (INIS)

    D'yakov, A.A.

    1984-01-01

    The review of studies dealing with the development of the method for the electro-chemical etching (ECE) of the plastic track detectors on the base of polyethy-leneterephthalate (PET) and polycarbonate (PC) is given. Physical essence of the method, basic parameters of the processes, applied equipment and methods of measurement automation are considered. The advantages of the method over the traditional chemical etching are pointed out. Recommendations on the detector operation modes when detecting fission fragments, α-particles and fast neutrons are given. The ECE method is based on the condition that during chemical etching the high-voltage sound frequency alternating electric field is applied to the detector. In this case the detector serves as an isolating layer betWeen two vessels with etching solution in which high-voltage electrode are submerged. At a fixed electric field potential higher (over than the threshold value) at the end of the etching track cone atree-like discharge spot arises. It is shown that when PET is used for fast neutron detection it is advisable to apply for ECE the PEW solution (15g KOH+40 g C 2 H 2 OH + 45g H 2 O) the field potential should constitute 30 kVxcm -1 at the freqUency of 9 kHz. In the case of fission fragment detection Using ECE and PC the following ECE conditions are recommended: 30% KOH etcher, field potential of 10 kVxcm -1 , 2-4 kHz frequency. It is concluded that the ECE method permits considerably eXtend the sphere of plastic track detector application for detecting ionizing particles,

  3. Comparison of fast neutron-induced tracks in plastics using the electrochemical etching method

    International Nuclear Information System (INIS)

    Cotter, S.J.; Gammage, R.B.; Thorngate, J.H.; Ziemer, P.L.

    1979-01-01

    Four plastics were examined by the electrochemical etching method for their suitability in registering fast neutron-induced recoil particle tracks. The plastics were cellulose acetate, cellulose triacetate, cellulose acetobutyrate and polycarbonate. Cellulose acetate and triacetate displayed high levels of water absorptivity during etching while the acetobutyrate foils cracked due to electromechanical stresses at high frequencies (>500 Hz). The clarity of the etched track was superior in the polycarbonate foils, suggesting the latter as the generally preferred dosimeter for fast neutrons. (author)

  4. Equipment for electrochemical etching of dielectric track detectors

    International Nuclear Information System (INIS)

    Turek, K.; Novak, M.

    1992-01-01

    The facility is designed for electrochemical etching of solid state track detectors, devised for thicknesses in excess of 200 μm as employed for direct detection of charged particles or neutrons. The device consists of a high-voltage a.c. supply for the electrodes and an assembly whose body consists of a flat tank, on the surface of which is formed a channel for feeding the heating and cooling media. The tank is covered by a gasket, an earthed metal plate for the detector, a mask with holes determining the shape of the etched area, and a pressure plate. The pressure plate is fitted with a system of holes for the etching solution. Needle-shaped high-voltage electrodes are accommodated in the holes of the mask. The underlying principle of the invention consists in the fact that a rubber pad with guide holes for the needle-shaped electrodes lies on the pressure plate. Each electrode is composed of a central tip and an outer jacket, separated by an insulating layer; connection is provided by a light emitting diode. (Z.S.). 2 figs

  5. CR-39 as induced track detector in reactor: irradiation effect

    International Nuclear Information System (INIS)

    Zylberberg, H.

    1989-07-01

    A systematic study about reactor's neutrons radiation effect and gamma radiation effect on the properties of CR-39 that are significant for its use as induced fission track detector is showed. The following studies deserved attention: kinetics of the fission track chemical development; efficiency to register and to develop fission track; losses of developable tracks; variation in the number of developable tracks and variation in the visible and ultraviolet radiation spectrum. The dissertation is organized in seven specific chapters: solid state nuclear tracks (SSNT); CR-39 as SSNT; objectives and problems presentation; preparation and characterization of CR-39 as SSNT; gamma irradiation effect on the properties of CR-39 as SSNT; reactor neutron irradiation effect on the properties of CR-39 as SSNT and, results discussions and conclusions. The main work contributions are the use of CR-39 in the determination of fissionable nuclide as thorium and uranium in solid and liquid samples; gamma radiation damage on CR-39 as well as the reactor's neutron damage on CR-39. (B.C.A.) 62 refs, 53 figs, 21 tabs

  6. Investigations of CR39 dosimeters for neutron routine dosimetry

    International Nuclear Information System (INIS)

    Weinstein, M.; Abraham, A.; Tshuva, A.; German, U.

    2004-01-01

    CR-39 is a polymeric nuclear track detector which is widely used for neutron dosimetry. CR-39 detector development was conducted at a number of laboratories throughout the world(1,2) , and was accepted also for routine dosimetry. However, there are shortcomings which must be taken into consideration the lack of a dosimetry grade material which causes batch variations, significant angular dependence and a moderate sensitivity. CR-39 also under-responds for certain classes of neutron spectra (lower energy neutrons from reactors or high energy accelerator-produced neutrons).In order to introduce CR-39 as a routine dosimeter at NRCN, a series of checks were performed. The present work describes the results of some of our checks, to characterize the main properties of CR-39 dosimeters

  7. Electrochemical processes for the environmental remediation of toxic Cr(VI): A review

    International Nuclear Information System (INIS)

    Jin, Wei; Du, Hao; Zheng, Shili; Zhang, Yi

    2016-01-01

    Highlights: • Recent advances in electrochemical technologies for practical Cr(VI) treatment applications was reviewed. • The mechanism and performance of electrocoagulation, electrochemical reduction, electrodialysis, electro-electrodialysis and electrodeionization were discussed and compared. • The remained challenges and future perspectives were commented. - Abstract: Hexavalent chromium Cr(VI) is extremely toxic and classified as one of the 17 chemicals posing the greatest threat to humans. Large amounts of Cr(VI) compounds are directly or indirectly discharged into the environment, therefore considerable efforts have been made to control the Cr(VI) concentration below the recommended level. It has been demonstrated that electrochemical technique is one of the most efficient and environmental benign approach for the Cr(VI) removal. This review aims at recent advances in electrochemical technology for practical Cr(VI) treatment applications. By using the “clean reagent” of electron, Cr(VI) can be completely eliminated or separated via different electrochemical techniques such as electrocoagulation, electrochemical reduction, electrodialysis, electro-electrodialysis and electrodeionization. Besides, the mechanism and performance of different strategies are commented and compared. The treatment process is largely dependent on variables such as pH, electrode materials, cell configuration and techniques integration. Furthermore, the remained limitation and challenges for the electrochemical Cr(VI) remediation are also discussed.

  8. Particularisation of Alpha Contamination using CR-39 Track Detectors

    International Nuclear Information System (INIS)

    Zakia, M.F.; El-Shaer, Y.H.

    2008-01-01

    Solid-state nuclear track detectors have found wide use in various domains of science and technology, e.g. in environmental experiments. The measurement of alpha activity on sources in an environment, such as air is not easy because of short penetration range of the alpha particles. Furthermore, the measurement of alpha activity by most gas ionization detectors suffers from the high background induced by the accompanying gamma radiation. Solid State Nuclear Track Detectors (SSNTDs) have been used successfully as detecting devices as passive system to detect the alpha contamination different surfaces. This work presents the response of CR-39 (for two types) to alpha particles from two sources, 238 Pu with energy 5 MeV and 241 Am with energy 5.4 MeV. The methods of etching and counting are investigated, along with the achievable linearity, efficiency and reproducibility. The sensitivity to low activity and energy resolution are studied

  9. Development of a Silicon Microneedle with Three-Dimensional Sharp Tip by Electrochemical Etching

    Science.gov (United States)

    Izumi, Hayato; Okamoto, Tokusuke; Suzuki, Masato; Aoyagi, Seiji

    Aiming at the use in low-invasive medical treatments, this paper reports a fabrication technique of silicon microneedle of conical sharp point. The electrochemical etching technique is employed for sharpening the tip of a pillar, which is diced from a silicon wafer. A finely smooth tip surface is obtained due to electrochemical etching reactions, and is effective for easy insertion. The fabrication method is based on inexpensive wet etching, which does not require expensive fabrication facilities such as deep reactive ion etching (DRIE). A sharp needle was successfully fabricated, the tip angle of which was considerably small and was distributed within the range from 15 to 30 deg. An experiment of inserting the fabricated needle into an artificial skin of silicone rubber was carried out. As the results, the resistance force during insertion was much reduced compared to those of two-dimensional sharp needles. Imitating mosquito's motion, the effectiveness of applying vibration to the fabricated needle during insertion was also confirmed. After biocompatible Parylene coating, puncturing a human skin was demonstrated assuming a lancet usage for the diabetics, in which the bleeding was surely observed.

  10. Optimization of CR-39 for fast neutron dosimetry applications

    International Nuclear Information System (INIS)

    Vilela, E.; Fantuzzi, E.; Giacomelli, G.; Giorgini, M.; Morelli, B.; Patrizii, L.; Serra, P.; Togo, V.

    1999-01-01

    We present the results of an experimental work aimed at improving the performances of the CR-39[reg] (Registered Trademark of PPG Industries Inc.) nuclear track detector for neutron dosimetry applications. The work was done in collaboration with the Intercast Europe S.p.A., producer of CR-39 for commercial and scientific applications. We compare the CR-39 made with different additives concentrations and different polymerization processes. We evaluate the response of the CR-39 to fast neutrons from three sources: 241 Am-Be, 252 Cf and 238 Pu-Li. Particular attention was paid to background fluctuations that limit the lower detectable dose

  11. Effect of Surface Treatment on Enamel Cracks After Orthodontic Bracket Debonding: Er,Cr:YSGG Laser-Etching Versus Acid-Etching

    Science.gov (United States)

    Ghaffari, Hassanali; Mirhashemi, Amirhossein; Baherimoghadam, Tahereh; Azmi, Amir

    2017-01-01

    Objectives: This study sought to compare enamel cracks after orthodontic bracket debonding in the surfaces prepared with erbium, chromium: yttrium-scandium-galliumgarnet (Er,Cr:YSGG) laser and the conventional acid-etching technique. Materials and Methods: This in-vitro experimental study was conducted on 60 sound human premolars extracted for orthodontic purposes. The teeth were randomly divided into two groups (n=30). The teeth in group A were etched with 37% phosphoric acid gel, while the teeth in group B were subjected to Er,Cr:YSGG laser irradiation (gold handpiece, MZ8 tip, 50Hz, 4.5W, 60μs, 80% water and 60% air). Orthodontic brackets were bonded to the enamel surfaces and were then debonded in both groups. The samples were inspected under a stereomicroscope at ×38 magnification to assess the number and length of enamel cracks before bonding and after debonding. Independent-samples t-test was used to compare the frequency of enamel cracks in the two groups. Levene’s test was applied to assess the equality of variances. Results: No significant difference was noted in the frequency or length of enamel cracks between the two groups after debonding (P>0.05). Conclusions: Despite the same results of the frequency and length of enamel cracks in the two groups and by considering the side effects of acid-etching (demineralization and formation of white spot lesions), Er,Cr:YSGG laser may be used as an alternative to acid-etching for enamel surface preparation prior to bracket bonding. PMID:29296111

  12. New approach of modeling charged particles track development in CR-39 detectors

    International Nuclear Information System (INIS)

    Azooz, A.A.; Hermsdorf, D.; Al-Jubbori, M.A.

    2013-01-01

    In this work, previous modeling of protons and alpha particles track length development in CR-39 solid state nuclear track detectors SSNTD is modified and further extended. The extension involved the accommodation of heavier ions into the model. These ions include deuteron, lithium, boron, carbon, nitrogen and oxygen ions. The new modeling does not contain any case sensitive free fitting parameters. Model calculation results are found to be in good agreement with both experimental data and SRIM software range energy dependence predictions. The access to a single unified and differentiable track length development equation results in the ability to obtain direct results for track etching rates. - Highlights: • New modeling of ions track length evolution measured by different authors. • Ions considered are p, d, α, Li, B, C, N, O. • Equations obtained to describe L(t) and etch rate for all ions at wide energy range. • Equations obtained do not involve any free fitting parameters. • Ions range values obtained compare well with results of SRIM software

  13. Measurement of track opening contours of oblique incident 4He and 7Li-ions in CR-39: Relevance for calculation of track formation parameters

    International Nuclear Information System (INIS)

    Hermsdorf, D.; Reichelt, U.

    2010-01-01

    Solid State Nuclear Track Detectors (SSNTD) irradiated in realistic radiation fields exhibits after chemical etching very complex track images resulting from different species of particles and their energy spectra and randomly distributed angles of incidence or emission. Reading out such an etched detector surface with a light microscope, quite different track opening contours are observed. Beside the number of tracks, typically their major and minor axes are measured. In this work following problems arising from such experimental situations will be investigated: ·the measurement of track contour parameters for oblique incident 4 He and 7 Li-ions of different energies and angles in CR-39 detectors ·the theoretical description of the angular variation of both axes. ·the possibility to extract physical and spectroscopic information from major and minor track axes. This analysis is based on an intensive experimental program and the comprehensive study of theoretical models available for description of track revealing processes in CR-39.

  14. Fast neutron detection using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Vilela, E.C.

    1990-01-01

    CR-39 and Makrofol-E solid state nuclear track detectors were studied aiming their application to fast neutron detection. Optimum etching conditions of those two kinds of materials were determined the followings - the Makrofol-E detector is electrochemically etched in a PEW solution (15% KOH, 40% ethilic alcohol and 45% water) for 2 h., with an applied electric field strength of 30 kV/cm (r/m/s/) and frequency of 2 kHz, at room temperature; - the CR-39 detector is chemically pre-etched during 1 h in a 20% (w/v) NaOH solution at 70 sup(0)C, followed by 13 h electrochemical etch using the same solution at room temperature and an electric field strength of 30 kV/cm (r.m.s.) and frequency of 2 kHz.(E.G.)

  15. Optimization of CR-39 for fast neutron dosimetry applications

    CERN Document Server

    Vilela, E; Giacomelli, G; Giorgini, M; Morelli, B; Patrizii, L; Serra, P; Togo, V

    1999-01-01

    We present the results of an experimental work aimed at improving the performances of the CR-39[reg] (Registered Trademark of PPG Industries Inc.) nuclear track detector for neutron dosimetry applications. The work was done in collaboration with the Intercast Europe S.p.A., producer of CR-39 for commercial and scientific applications. We compare the CR-39 made with different additives concentrations and different polymerization processes. We evaluate the response of the CR-39 to fast neutrons from three sources: sup 2 sup 4 sup 1 Am-Be, sup 2 sup 5 sup 2 Cf and sup 2 sup 3 sup 8 Pu-Li. Particular attention was paid to background fluctuations that limit the lower detectable dose.

  16. Precise thickness control in recess etching of AlGaN/GaN hetero-structure using photocarrier-regulated electrochemical process

    Science.gov (United States)

    Kumazaki, Yusuke; Uemura, Keisuke; Sato, Taketomo; Hashizume, Tamotsu

    2017-05-01

    The photocarrier-regulated electrochemical (PREC) process was developed for fabricating recessed-gate AlGaN/GaN high-electron-mobility transistors (HEMTs) for normally off operation. The PREC process is based on photo-assisted electrochemical etching using low-energy chemical reactions. The fundamental photo-electrochemical measurements on AlGaN/GaN heterostructures revealed that the photo-carriers generated in the top AlGaN layer caused homogeneous etching of AlGaN with a smooth surface, but those generated in the GaN layer underneath caused inhomogeneous etching that roughens the surface. The concept of the PREC process is to supply the photo-carriers generated only in the AlGaN layer by selecting proper conditions on light wavelength and voltage. The phenomenon of self-termination etching has been observed during the PREC process, where the etching depth was controlled by light intensity. The recessed-gate AlGaN/GaN HEMT fabricated with the PREC process showed positive threshold voltage and improvement in transconductance compared to planar-gate AlGaN/GaN HEMTs.

  17. Neutron activation analysis of uranium by means of electrochemical etching of tracks in lawsan detectors

    International Nuclear Information System (INIS)

    Kim Son Chun; Chuburkov, Yu.T.; Zvara, I.I.

    1982-01-01

    The method of neutron activation analysis of uranium in natural and artificial materials using track lavsan detectors of fission fragments has been developed. The method of electrochemical etching (etching reagent NaOH) of fragment tracks in lavsan is improved. Using statistical method of experiment planning the equation, describing the dependence of diometer value of fission fragment tracks on parameters of etching process, is obtained. The analysis sensitivity is 10 - 7 g/g - 10 - 8 g/g

  18. Enhanced electrochemical etching of ion irradiated silicon by localized amorphization

    Energy Technology Data Exchange (ETDEWEB)

    Dang, Z. Y.; Breese, M. B. H. [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore Singapore 117542 (Singapore); Lin, Y.; Tok, E. S. [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Vittone, E. [Physics Department, NIS Excellence Centre and CNISM, University of Torino, via Pietro Giuria 1, 10125 Torino (Italy)

    2014-05-12

    A tailored distribution of ion induced defects in p-type silicon allows subsequent electrochemical anodization to be modified in various ways. Here we describe how a low level of lattice amorphization induced by ion irradiation influences anodization. First, it superposes a chemical etching effect, which is observable at high fluences as a reduced height of a micromachined component. Second, at lower fluences, it greatly enhances electrochemical anodization by allowing a hole diffusion current to flow to the exposed surface. We present an anodization model, which explains all observed effects produced by light ions such as helium and heavy ions such as cesium over a wide range of fluences and irradiation geometries.

  19. Thermal stability of dyed tracks and electrochemical etching sensitivity of some polymeric detectors

    International Nuclear Information System (INIS)

    Monnin, M.; Gourcy, J.; Somogyi, G.; Dajko, D.

    1980-01-01

    Recent results on the mechanism of the formation of tracks obtained by the dyed tracks technique are given and the thermal annealing of the detectors is used to demonstrate their ability to retain tracks under more severe conditions than by the etching technique. Electrochemical etching of polycarbonate and polyethylene terephthalate detectors is investigated both from the background and sensitivity points of view. The polyethylene terephthalate detector is shown to be well suited for low neutron flux measurements. (author)

  20. Texture-Etched SnO2 Glasses Applied to Silicon Thin-Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Bing-Rui Wu

    2014-01-01

    Full Text Available Transparent electrodes of tin dioxide (SnO2 on glasses were further wet-etched in the diluted HCl:Cr solution to obtain larger surface roughness and better light-scattering characteristic for thin-film solar cell applications. The process parameters in terms of HCl/Cr mixture ratio, etching temperature, and etching time have been investigated. After etching process, the surface roughness, transmission haze, and sheet resistance of SnO2 glasses were measured. It was found that the etching rate was increased with the additions in etchant concentration of Cr and etching temperature. The optimum texture-etching parameters were 0.15 wt.% Cr in 49% HCl, temperature of 90°C, and time of 30 sec. Moreover, silicon thin-film solar cells with the p-i-n structure were fabricated on the textured SnO2 glasses using hot-wire chemical vapor deposition. By optimizing the texture-etching process, the cell efficiency was increased from 4.04% to 4.39%, resulting from the increment of short-circuit current density from 14.14 to 15.58 mA/cm2. This improvement in cell performances can be ascribed to the light-scattering effect induced by surface texturization of SnO2.

  1. Plasma treatment of porous GaAs surface formed by electrochemical etching method: Characterization and properties

    International Nuclear Information System (INIS)

    Saloum, S.; Naddaf, M.

    2010-01-01

    Porous GaAs samples were formed by electrochemical anodic etching of Zn doped p-type GaAs (100) wafers at different etching parameters (time, mode of applied voltage or current and electrolyte). The effect of etching parameters and plasma surface treatment on the optical properties of the prepared sample has been investigated by using room temperature photoluminescence (PL), Raman spectroscopy and reflectance spectroscopic measurements in the range (400-800 nm). The surface morphological changes were studied by using atomic force microscope. (author)

  2. Evaluation study between the chemical and electrochemical etching for solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Ramos, S.; Espinosa, G.; Golzarri, J.I.

    1991-01-01

    Since there are several methods of etching in the solid state nuclear track detectors (SSNTD) it is necessary to know which gives the best results for a specific problem. The purpose of this work is to analyze and compare both the chemical etching and the electrochemical etching. The SSNTD has a preferential response to certain kinds of particles and energies, according to the material used as detector. On the other hand the efficiency is a function of the incidence angle of the radiation and some other parameters such as temperature, concentration and type of solvent used in the etching process, and the method used for the etching. Therefore, it is necessary to extend as much as possible our knowledge of such parameters in order to choose the more efficient one for a specific problem

  3. Porous CrN thin films by selectively etching CrCuN for symmetric supercapacitors

    KAUST Repository

    Wei, Binbin

    2018-03-18

    Transition metal nitrides are regarded as a new class of excellent electrode materials for high-performance supercapacitors due to their superior chemical stability and excellent electrical conductivity. We synthesize successfully the porous CrN thin films for binder-free supercapacitor electrodes by reactive magnetron co-sputtering and selective chemical etching. The porous CrN thin film electrodes exhibit high-capacitance performance (31.3 mF cm−2 at 1.0 mA cm−2) and reasonable cycling stability (94% retention after 20000 cycles). Moreover, the specific capacitance is more than two-fold higher than that of the CrN thin film electrodes in previous work. In addition, a symmetric supercapacitor device with a maximum energy density of 14.4 mWh cm−3 and a maximum power density of 6.6 W cm−3 is achieved. These findings demonstrate that the porous CrN thin films will have potential applications in supercapacitors.

  4. Porous CrN thin films by selectively etching CrCuN for symmetric supercapacitors

    Science.gov (United States)

    Wei, Binbin; Mei, Gui; Liang, Hanfeng; Qi, Zhengbing; Zhang, Dongfang; Shen, Hao; Wang, Zhoucheng

    2018-05-01

    Transition metal nitrides are regarded as a new class of excellent electrode materials for high-performance supercapacitors due to their superior chemical stability and excellent electrical conductivity. We synthesize successfully the porous CrN thin films for binder-free supercapacitor electrodes by reactive magnetron co-sputtering and selective chemical etching. The porous CrN thin film electrodes exhibit high-capacitance performance (31.3 mF cm-2 at 1.0 mA cm-2) and reasonable cycling stability (94% retention after 20000 cycles). Moreover, the specific capacitance is more than two-fold higher than that of the CrN thin film electrodes in previous work. In addition, a symmetric supercapacitor device with a maximum energy density of 14.4 mWh cm-3 and a maximum power density of 6.6 W cm-3 is achieved. These findings demonstrate that the porous CrN thin films will have potential applications in supercapacitors.

  5. Excimer laser beam profile recording based on electrochemical etched polycarbonate

    International Nuclear Information System (INIS)

    Parvin, P.; Jaleh, B.; Zangeneh, H.R.; Zamanipour, Z.; Davoud-Abadi, Gh.R.

    2008-01-01

    There is no polymeric detector used to register the beam profile of UV lasers. Here, a method is proposed for the measurement of intensive UV beam pattern of the excimer lasers based on the photoablated polycarbonate detector after coherent UV exposure and the subsequent electrochemical etching. UV laser induced defects in the form of self-microstructuring on polycarbonate are developed to replicate the spatial intensity distribution as a beam profiler

  6. Excimer laser beam profile recording based on electrochemical etched polycarbonate

    Energy Technology Data Exchange (ETDEWEB)

    Parvin, P. [Physics Department, Amirkabir University of Technology, P.O. Box 15875-4413, Hafez Ave, Tehran (Iran, Islamic Republic of); Laser Research Center, AEOI, P.O. Box 1165-8486, Tehran (Iran, Islamic Republic of)], E-mail: parvin@aut.ac.ir; Jaleh, B. [Physics Department, Bu-Ali Sina University, Postal Code 65174, Hamedan (Iran, Islamic Republic of); Zangeneh, H.R. [Physics Department, Amirkabir University of Technology, P.O. Box 15875-4413, Hafez Ave, Tehran (Iran, Islamic Republic of); Zamanipour, Z. [Laser Research Center, AEOI, P.O. Box 1165-8486, Tehran (Iran, Islamic Republic of); Davoud-Abadi, Gh.R. [Physics Department, Amirkabir University of Technology, P.O. Box 15875-4413, Hafez Ave, Tehran (Iran, Islamic Republic of)

    2008-08-15

    There is no polymeric detector used to register the beam profile of UV lasers. Here, a method is proposed for the measurement of intensive UV beam pattern of the excimer lasers based on the photoablated polycarbonate detector after coherent UV exposure and the subsequent electrochemical etching. UV laser induced defects in the form of self-microstructuring on polycarbonate are developed to replicate the spatial intensity distribution as a beam profiler.

  7. Theoretical calculation on CR-39 response for radon measurements and optimum diffusion chambers dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Askari, H.R.; Ghandi, Kh. [Department of Physics, Faculty of Science, Vali-e-Asr University, Rafsanjan 7713936417 (Iran, Islamic Republic of); Rahimi, M. [Department of Physics, Faculty of Science, Vali-e-Asr University, Rafsanjan 7713936417 (Iran, Islamic Republic of)], E-mail: rahimi_bam@yahoo.com; Negarestani, A. [International Center for Science and High Technology and Environmental Sciences, Kerman (Iran, Islamic Republic of)

    2008-11-11

    One method to measure radon gas concentration in the air with a long time of radiation is trace chemical etching technique. There is a direct proportion between the number of traces on solid-state nuclear track detectors (SSNTDs) and activity concentration of radon. In this paper, calibration constant for a cylindrical chamber with CR-39 detector has been measured analytically. Using this measurement, trace curves on the base of concentration for chambers with different heights and radii have been drawn. The results show that to measure radon gas concentration, the optimum chamber should have a height between 3.5 and 4 cm and a radius between 2.5 and 3.2 cm.

  8. Theoretical calculation on CR-39 response for radon measurements and optimum diffusion chambers dimensions

    International Nuclear Information System (INIS)

    Askari, H.R.; Ghandi, Kh.; Rahimi, M.; Negarestani, A.

    2008-01-01

    One method to measure radon gas concentration in the air with a long time of radiation is trace chemical etching technique. There is a direct proportion between the number of traces on solid-state nuclear track detectors (SSNTDs) and activity concentration of radon. In this paper, calibration constant for a cylindrical chamber with CR-39 detector has been measured analytically. Using this measurement, trace curves on the base of concentration for chambers with different heights and radii have been drawn. The results show that to measure radon gas concentration, the optimum chamber should have a height between 3.5 and 4 cm and a radius between 2.5 and 3.2 cm.

  9. CR-39 plastic nuclear track detector and its application in nuclear science

    International Nuclear Information System (INIS)

    Zhai Pengji; Tang Xiaowei; Wang Long; Liang Tianjiao

    2000-01-01

    The transparent and stable plastic material CR-39 can be used as a nuclear track detector which is highly sensitive to charged particles. It can record tracks induced by protons , alphas, fission fragments and other charged particles. Among various available solid state nuclear track detectors CR-39 has the lowest deposited energy density detection-threshold. The response of CR-39 to charged particles and the response curve of υ T of different charged particles to REL are given. The CR-39 detector is widely used in studies of nuclear reactions, angular distributions and reaction cross-sections caused by neutrons and charged particles. Neutron spectra, over a wide energy range, can be measured by the combination of CR-39 and a transformation screen. The successful applications of CR-39 in alpha particle dosimetry, environmental science (especially in the measurement of radon) and in biomedicine, such as the analysis of alpha radioactivity in sections of organic tissues, are described

  10. Measurement of low neutron-fluences using electrochemically etched PC and PET track detectors

    International Nuclear Information System (INIS)

    Somogyi, G.; Dajko, G.; Turek, K.; Spurny, F.

    1979-01-01

    Systematic investigations have been carried out to study different properties of electrochemically etched (ECE) polycarbonate (PC) and polyethylene-terephthalate (PET) foils. The dependence of the density of background discharge spots on surface-thickness removal, electrical field strength and frequency of voltage is given. The effect of these parameters on the neutron sensitivity of polycarbonate and polyethylene-terephthalate foils irradiated at right angles to 14.7 MeV, 241 Am-Be and 252 Cf neutrons is also studied. With knowledge of the background and sensitivity data, the etching and electrical parameters are optimized for low neutron-fluence measurements. (author)

  11. Electrochemically etched nanoporous silicon membrane for separation of biological molecules in mixture

    Science.gov (United States)

    Burham, Norhafizah; Azlan Hamzah, Azrul; Yunas, Jumril; Yeop Majlis, Burhanuddin

    2017-07-01

    This paper presents a technique for separating biological molecules in mixture using nanoporous silicon membrane. Nanopores were formed using electrochemical etching process (ECE) by etching a prefabricated silicon membrane in hydrofluoric acid (HF) and ethanol, and then directly bonding it with PDMS to form a complete filtration system for separating biological molecules. Tygon S3™ tubings were used as fluid interconnection between PDMS molds and silicon membrane during testing. Electrochemical etching parameters were manipulated to control pore structure and size. In this work, nanopores with sizes of less than 50 nm, embedded on top of columnar structures have been fabricated using high current densities and variable HF concentrations. Zinc oxide was diluted with deionized (DI) water and mixed with biological molecules and non-biological particles, namely protein standard, serum albumin and sodium chloride. Zinc oxide particles were trapped on the nanoporous silicon surface, while biological molecules of sizes up to 12 nm penetrated the nanoporous silicon membrane. The filtered particles were inspected using a Zetasizer Nano SP for particle size measurement and count. The Zetasizer Nano SP results revealed that more than 95% of the biological molecules in the mixture were filtered out by the nanoporous silicon membrane. The nanoporous silicon membrane fabricated in this work is integratable into bio-MEMS and Lab-on-Chip components to separate two or more types of biomolecules at once. The membrane is especially useful for the development of artificial kidney.

  12. Laser surface pretreatment of 100Cr6 bearing steel – Hardening effects and white etching zones

    International Nuclear Information System (INIS)

    Buling, Anna; Sändker, Hendrik; Stollenwerk, Jochen; Krupp, Ulrich; Hamann-Steinmeier, Angela

    2016-01-01

    Highlights: • Laser surface pretreatment of the bearing steel 100Cr6 is performed. • Microstructural changes of the surface are examined by light microscopy and SEM. • Topographical changes are observed using white light interferometry. • Micro-hardness testing show the existence of very hard white etching zones (WEZ). • WEZ are attributed to near-surface reaustenitization and rapid quenching. • Dark etching zones (DEZ) are found at the laser path edges after laser pretreatment. - Abstract: In order to achieve a surface pretreatment of the bearing steel 100Cr6 (1–1.5 wt.% Cr) a laser-based process was used. The obtained modification may result in an optimization of the adhesive properties of the surface with respect to an anticorrosion polymer coating on the basis of PEEK (poly-ether-ether-ketone), which is applied on the steel surface by a laser melting technique. This work deals with the influence of the laser-based pretreatment regarding the surface microstructure and the micro-hardness of the steel, which has been examined by scanning electron microscopy (SEM), light microscopy and automated micro-hardness testing. The most suitable parameter set for the laser-based pretreatment leads to the formation of very hard white etching zones (WEZ) with a thickness of 23 μm, whereas this pretreatment also induces topographical changes. The occurrence of the white etching zones is attributed to near-surface re-austenitization and rapid quenching. Moreover, dark etching zones (DEZ) with a thickness of 32 μm are found at the laser path edges as well as underneath the white etching zones (WEZ). In these areas, the hardness is decreased due to the formation of oxides as a consequence of re-tempering.

  13. Laser surface pretreatment of 100Cr6 bearing steel – Hardening effects and white etching zones

    Energy Technology Data Exchange (ETDEWEB)

    Buling, Anna, E-mail: a.buling@hs-osnabrueck.de [Faculty of Engineering and Computer Science, University of Applied Sciences, 49009 Osnabrück (Germany); Sändker, Hendrik; Stollenwerk, Jochen [Fraunhofer Institute for Laser Technology ILT, Steinbachstrasse 15, 52074 Aachen (Germany); Krupp, Ulrich; Hamann-Steinmeier, Angela [Faculty of Engineering and Computer Science, University of Applied Sciences, 49009 Osnabrück (Germany)

    2016-08-15

    Highlights: • Laser surface pretreatment of the bearing steel 100Cr6 is performed. • Microstructural changes of the surface are examined by light microscopy and SEM. • Topographical changes are observed using white light interferometry. • Micro-hardness testing show the existence of very hard white etching zones (WEZ). • WEZ are attributed to near-surface reaustenitization and rapid quenching. • Dark etching zones (DEZ) are found at the laser path edges after laser pretreatment. - Abstract: In order to achieve a surface pretreatment of the bearing steel 100Cr6 (1–1.5 wt.% Cr) a laser-based process was used. The obtained modification may result in an optimization of the adhesive properties of the surface with respect to an anticorrosion polymer coating on the basis of PEEK (poly-ether-ether-ketone), which is applied on the steel surface by a laser melting technique. This work deals with the influence of the laser-based pretreatment regarding the surface microstructure and the micro-hardness of the steel, which has been examined by scanning electron microscopy (SEM), light microscopy and automated micro-hardness testing. The most suitable parameter set for the laser-based pretreatment leads to the formation of very hard white etching zones (WEZ) with a thickness of 23 μm, whereas this pretreatment also induces topographical changes. The occurrence of the white etching zones is attributed to near-surface re-austenitization and rapid quenching. Moreover, dark etching zones (DEZ) with a thickness of 32 μm are found at the laser path edges as well as underneath the white etching zones (WEZ). In these areas, the hardness is decreased due to the formation of oxides as a consequence of re-tempering.

  14. Measurement of indoor radon concentration by CR-39 track detector

    International Nuclear Information System (INIS)

    Yamamoto, Masayoshi; Yoneda, Shigeru; Nakanishi, Takashi.

    1990-01-01

    A convenient and cheap method for measuring indoor radon ( 222 Rn) concentration with a CR-39 track detector is described. The detector consisted of two sheets of CR-39 enclosed separately in two plastic pots : one covered by a filter (cup method) and another no covering (bare method). The bare method was used here to supplement the cup method. To compare with the result of the CR-39 detector, alpha-ray spectrometry was carried out with a Si(Au) detector in a controlled radon exposure chamber. Indoor radon concentration measured in 133 houses in several districts of Ishikawa Prefecture have been found to range from 6 Bq/m 3 to as high as 113 Bq/m 3 with a median value of 24 Bq/m 3 . The problems to measure indoor radon concentration using the CR-39 detector are also discussed with emphasis on the position of setting the detector in the room and the possible thoron contribution to the detector. (author)

  15. Nuclear tracks in CR-39 produced by carbon, oxygen, aluminium and titanium ions.

    Science.gov (United States)

    Rickards, J; Romo, V; Golzarri, J I; Espinosa, G

    2002-01-01

    This work describes the response of CR-39 (allyl diglycol polycarbonate) to different ions (C, O, Al and Ti) produced by the Instituto de Fisica 3 MV 9SDH-2 Pelletron accelerator and backscattered from a thin Au film on a C support. The ion energies were chosen in series such that the ranges of the different ions in the detector were 2, 3, 4, 5, 6, 7 and 8 microm respectively for each series. Once exposed, the detectors were etched with a solution of 6.25 M KOH at 60 degrees C, and the reading was carried out using a digital image analysis system. An analysis of the measured track diameters of all the types of ions indicates that, for a given range, track kinetics are independent of type of ion, energy and stopping power.

  16. Dose-equivalent response CR-39 track detector for personnel neutron dosimetry

    International Nuclear Information System (INIS)

    Oda, K.; Ito, M.; Yoneda, H.; Miyake, H.; Yamamoto, J.; Tsuruta, T.

    1991-01-01

    A dose-equivalent response detector based on CR-39 has been designed to be applied for personnel neutron dosimetry. The intrinsic detection efficiency of bare CR-39 was first evaluated from irradiation experiments with monoenergetic neutrons and theoretical calculations. In the second step, the radiator effect was investigated for the purpose of sensitization to fast neutrons. A two-layer radiator consisting of deuterized dotriacontane (C 32 D 66 ) and polyethylene (CH 2 ) was designed. Finally, we made the CR-39 detector sensitive to thermal neutrons by doping with orthocarbone (B 10 H 12 C 2 ), and also estimated the contribution of albedo neutrons. It was found that the new detector - boron-doped CR-39 with the two-layer radiator - would have a flat response with an error of about 70% in a wide energy region, ranging from thermal to 15 MeV. (orig.)

  17. Applications of CR-39 solid state nuclear track detector to ion beam diagnosis

    International Nuclear Information System (INIS)

    Kanasaki, Masato; Hattori, Atsuto; Oda, Keiji; Yamauchi, Tomoya; Fukuda, Yuji; Sakaki, Hironao; Nishiuchi, Mamiko; Kondo, Kiminori; Kurashima, Satoshi; Kamiya, Tomihiro

    2012-01-01

    CR-39 solid state nuclear track detector, which was developed for optical lens, has been applied for various field such as radon surveys, measurement of galactic cosmic ray, cell irradiation experiment and so on. The CR-39 detectors have the great advantages of being insensitive to high energy photons and electrons and capable of detecting only ions in the mixed fields such as laser driven relativistic plasmas. Though there are some analytical methods of CR-39 to diagnose ion beam, unfortunately, only few researchers in the field of plasma know the methods. This article looks at how to use CR-39 detectors and introduce the accomplishment of the joint study JAEA and Kobe Univ. for application of CR-39 detectors to ion beam diagnosis. (author)

  18. Study of /sup 210/Pb and /sup 210/Po distributions in environmental samples by CR-39 track detector

    Energy Technology Data Exchange (ETDEWEB)

    Hunyadi, I.; Somogyi, G.; Szilagyi, S. (Magyar Tudomanyos Akademia, Debrecen. Atommag Kutato Intezete)

    1984-01-01

    Activity concentration distributions of long-lived alpha-emitters in aerosol samples are analysed by high-resolution autoradiography in CR-39. A study of the alpha-activity attached to aerosols of different particulate sizes separated by a cascade impactor is also performed. It is found that, in the majority of samples, the alpha-activity can be dominantly related to the presence of /sup 210/Po produced by its beta-active precursor /sup 210/Pb. In our studies we have applied the following methods: 1) analysis of alpha-decay properties by means of autoradiographs taken at different post-sampling times, 2) spectroscopical study of individual alpha-tracks and track clusters by a method developed by us for high-resolution alpha-energy determination. In the second method the parameters to be measured are the major axis of surface track opening, the diameter of etched out track end, the total length measurable on the surface along the projected track, and the thickness of layer etched away from the detector surface.

  19. Calculation of thermal effects occurring during the manufacture of CR-39 sheets

    Energy Technology Data Exchange (ETDEWEB)

    Szilagyi, S.; Somogyi, G. (Magyar Tudomanyos Akademia, Debrecen. Atommag Kutato Intezete)

    1984-01-01

    To manufacture a good-quality, uniform CR-39 track detector, the polymerization rate should be chosen below a critical value to avoid the development of undesirable thermal gradients and internal temperature fluctuations in the sheet being cast. To improve curing cycles, especially for thick CR-39 sheets, a computer programme was developed by which we could study the trends of thermal effects under different casting conditions. Our calculations are based on the solution of the one dimensional heat transport equation, taking into account the relations proposed by Dial et al (1955) for describing the chemical kinetics of CR-39 polymerization. We have revised the empirical parameters available to such calculations. With new 'Dial constants' we have calculated the critical initial bath temperature (which results in thermal runaway at the central plane of the sheet being cast) as a function of the CR-39 thickness and IPP initiator concentration. Results are also presented for the temperature profile developing in the depth of cast CR-39 sheets.

  20. Calculation of thermal effects occurring during the manufacture of CR-39 sheets

    International Nuclear Information System (INIS)

    Szilagyi, S.; Somogyi, G.

    1984-01-01

    To manufacture a good-quality, uniform CR-39 track detector, the polymerization rate should be chosen below a critical value to avoid the development of undesirable thermal gradients and internal temperature fluctuations in the sheet being cast. To improve curing cycles, especially for thick CR-39 sheets, a computer programme was developed by which we could study the trends of thermal effects under different casting conditions. Our calculations are based on the solution of the one dimensional heat transport equation, taking into account the relations proposed by Dial et al (1955) for describing the chemical kinetics of CR-39 polymerization. We have revised the empirical parameters available to such calculations. With new 'Dial constants' we have calculated the critical initial bath temperature (which results in thermal runaway at the central plane of the sheet being cast) as a function of the CR-39 thickness and IPP initiator concentration. Results are also presented for the temperature profile developing in the depth of cast CR-39 sheets. (author)

  1. Plasma treatment of porous GaAs surface formed by electrochemical etching method: Characterization and properties

    International Nuclear Information System (INIS)

    Naddaf, M.; Saloum, S.

    2008-12-01

    Porous GaAs samples were formed by electrochemical anodic etching of Zn doped p-type GaAs (100) wafers at different etching parameters (time, mode of applied voltage or current and electrolyte). The effect of etching parameters and plasma surface treatment on the optical properties of the prepared sample has been investigated by using room temperature photoluminescence (PL), Raman spectroscopy and reflectance spectroscopic measurements in the range (400-800 nm). The surface morphological changes were studied by using atomic force microscope. It has been found that etching parameters can be controlled to produce a considerably low optical reflectivity porous GaAs layer, attractive for use in solar cells. In addition, it has been observed that the deposition of plasma polymerized HMDSO thin film on porous GaAs surface can be utilized to produce a surface with novel optical properties interesting for solar cells and optoelectronic devices. (author)

  2. gamma-induced modification on optical band gap of CR-39 SSNTD

    International Nuclear Information System (INIS)

    Zaki, M.F.

    2010-01-01

    effect of gamma irradiation on optical absorption of nuclear track detectors like CR-39 was studied at different absorbed doses using ultraviolet-visible (UV-VIS)spectroscopy. the existence of the peaks, their shifting and broadening as a result of gamma irradiation has been discussed. the width of the tail of localized states in the band gap (E u )was evaluated using the Urbach edge method. finally the indirect and direct band gap in pristine and gamma irradiated CR-39 have been determined. the values of indirect band gap have been found to be lower than the corresponding values of direct band gap. a decrease in the optical energy gap with increasing the gamma absorbed dose can be discussed on the basis of gamma-irradiation-induced defects in the CR-39. the correlation between optical band gap and the number of carbon atoms in a cluster with modified Tauc's equation has been discussed in case of CR-39.

  3. Energy spectrum of iron nuclei measured inside the MIR space craft using CR-39 track detectors

    International Nuclear Information System (INIS)

    Guenther, W.; Leugner, D.; Becker, E.; Flesch, F.; Heinrich, W.; Huentrup, G.; Reitz, G.; Roecher, H.; Streibel, T.

    1999-01-01

    We have exposed stacks of CR-39 plastic nuclear track detectors inside the MIR space craft during the EUROMIR95 space mission for almost 6 months. Over this long period a large number of tracks of high LET events was accumulated in the detector foils. The etching and measuring conditions for this experiment were optimized to detect tracks of stopping iron nuclei. We found 185 stopping iron nuclei inside the stack and identified their trajectories through the material of the experiment. Based on the energy-range relation the energy at the surface of the stack was determined. These particles allow the determination of the low energy part of the spectrum of iron nuclei behind shielding material inside the MIR station

  4. Electrochemical synthesis of gold nanorods in track-etched polycarbonate membrane using removable mercury cathode

    International Nuclear Information System (INIS)

    Sharma, Manoj K.; Ambolikar, Arvind S.; Aggarwal, Suresh K.

    2012-01-01

    The electrochemical template synthesis of gold nanorods within the cylindrical pores of track-etched polycarbonate (PC) membrane using a removable mercury cathode is reported. The novelty of this new approach is that it eliminates the requirement of coating an approximately 500 nm–1 μm-thick metallic layer, as conducting substrate, onto one surface of the insulating template membrane by the sputter deposition technique. A two-compartment electrochemical cell was designed and used for this work. The PC membrane was placed between the two compartments separating the aqueous solution of HAuCl 4 from mercury. Mercury, filled in one of the compartments, is in contact with one surface of the membrane (similar to sputter-deposited metallic layer) and serves as the conducting substrate/cathode for the electrochemical deposition of gold in the nanopores of track-etched PC membrane. Once the electrodeposition is completed, the mercury and the HAuCl 4 solution are removed from the compartments, and a malleable track-etched PC membrane embedded with free-standing gold nanorods is obtained. The ensemble of the metal nanorods grown in the template membrane is not attached to any conducting substrate, and gold nanorods can be freed from the template membrane after the dissolution. The Au-deposited PC membrane and free-standing Au nanorods were characterized by EDXRF, XRD, UV–Visible spectroscopy, AFM, and FEG-TEM. The EDXRF and XRD studies confirmed the deposition of the face-centered cubic phase of Au in the pores of the PC membrane. The TEM studies showed the formation of a cigar-shaped gold nanorod in the cylindrical pores of the PC membrane. The diameter of gold nanorods ranges from 100 to 200 nm. The new approach is simple, cost-effective, and saves time.

  5. Effect of Etching Parameter on Pore Size and Porosity of Electrochemically Formed Nanoporous Silicon

    Directory of Open Access Journals (Sweden)

    Pushpendra Kumar

    2007-01-01

    Full Text Available The most common fabrication technique of porous silicon (PS is electrochemical etching of a crystalline silicon wafer in a hydrofluoric (HF acid-based solution. The electrochemical process allows for precise control of the properties of PS such as thickness of the porous layer, porosity, and average pore diameter. The control of these properties of PS was shown to depend on the HF concentration in the used electrolyte, the applied current density, and the thickness of PS. The change in pore diameter, porosity, and specific surface area of PS was investigated by measuring nitrogen sorption isotherms.

  6. High-aspect ratio micro- and nanostructures enabled by photo-electrochemical etching for sensing and energy harvesting applications

    Science.gov (United States)

    Alhalaili, Badriyah; Dryden, Daniel M.; Vidu, Ruxandra; Ghandiparsi, Soroush; Cansizoglu, Hilal; Gao, Yang; Saif Islam, M.

    2018-03-01

    Photo-electrochemical (PEC) etching can produce high-aspect ratio features, such as pillars and holes, with high anisotropy and selectivity, while avoiding the surface and sidewall damage caused by traditional deep reactive ion etching (DRIE) or inductively coupled plasma (ICP) RIE. Plasma-based techniques lead to the formation of dangling bonds, surface traps, carrier leakage paths, and recombination centers. In pursuit of effective PEC etching, we demonstrate an optical system using long wavelength (λ = 975 nm) infra-red (IR) illumination from a high-power laser (1-10 W) to control the PEC etching process in n-type silicon. The silicon wafer surface was patterned with notches through a lithography process and KOH etching. Then, PEC etching was introduced by illuminating the backside of the silicon wafer to enhance depth, resulting in high-aspect ratio structures. The effect of the PEC etching process was optimized by varying light intensities and electrolyte concentrations. This work was focused on determining and optimizing this PEC etching technique on silicon, with the goal of expanding the method to a variety of materials including GaN and SiC that are used in designing optoelectronic and electronic devices, sensors and energy harvesting devices.

  7. Interaction of 84 MeV/u 12C with 208Pb target investigated with CR-39 plastic track detector

    International Nuclear Information System (INIS)

    Grabez, B.

    1984-01-01

    The interaction of the 84 MeV/u 12 C ions with 208 Pb target was investigated using CR-39 plastic track detector. The first part of the work was dedicated to the examination of the methodology of the recently presented CR-39 detector and its calibration. Measurements have been done on tracks of various ions in the broad atomic number region from Z = 2 to Z = 92. The possibility of the identification of low energy fragments produced in nuclear interactions by measurements on the finished tracks was studied. Our results show that very good charge resolution can be achieved through determination of the mean etch rate ratio and the range of low energy ions. In the second part of the work it was shown that the main reaction channels in the interaction of 84 MeV/u C with Pb target are spallation, fission and fragmentation. The contribution of the multifragmentation is less than 1% of the total reaction cross section. From our results follows that the most probable reaction channels after collision with small impact parameter are fragmentation and deep spallation. The spallation and fission come after more peripheral collisions. (orig./HSI)

  8. Polymerization, structure and track recording properties of CR-39 cured with UV photoinitiators

    International Nuclear Information System (INIS)

    Stejny, J.; Carrell, J.; Palmer, M.J.

    2000-01-01

    CR-39 monomer was cured isothermally at temperatures from 54.5 to 115 deg. C with UV sensitive photoinitiators to high conversions. The use of photoinitiators allowed the cure of CR-39 isothermally at high temperatures and eliminated the danger of thermal runaway present in the conventionally used thermal initiation with peroxides. It was found that the properties of the UV photoinitiated CR-39 were similar to the conventionally polymerized resin

  9. Usage of an interactive image analysis system for studying various parameters of etched tracks in CR-39 and Makrofol E

    International Nuclear Information System (INIS)

    Abu-Jarad, F.; Islam, M.A.; Que, A.

    1991-01-01

    An Automated Interactive Built Analysis System (IBAS) is being used to analyze the alpha and fission fragment tracks in CR-39 and Makrofol E detectors. It primarily consists of a control computer (IBAS1) and an image processor (IBAS2). The system is used for counting the nuclear tracks, measuring their areas, diameters, statistics and displaying the frequency distribution of their sizes. All information can be printed out or stored on floppy disks. (author)

  10. A performance test of a new high-surface-quality and high-sensitivity CR-39 plastic nuclear track detector – TechnoTrak

    Energy Technology Data Exchange (ETDEWEB)

    Kodaira, S., E-mail: kodaira.satoshi@qst.go.jp [Radiation Measurement Research Team, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba (Japan); Morishige, K. [Research Institute for Science and Engineering, Waseda University, Tokyo (Japan); Kawashima, H.; Kitamura, H.; Kurano, M. [Radiation Measurement Research Team, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba (Japan); Hasebe, N. [Research Institute for Science and Engineering, Waseda University, Tokyo (Japan); Koguchi, Y.; Shinozaki, W. [Oarai Research Center, Chiyoda Technol Corporation, Ibaraki (Japan); Ogura, K. [College of Industrial Technology, Nihon University, Chiba (Japan)

    2016-09-15

    We have studied the performance of a newly-commercialized CR-39 plastic nuclear track detector (PNTD), “TechnoTrak”, in energetic heavy ion measurements. The advantages of TechnoTrak are derived from its use of a purified CR-39 monomer to improve surface quality combined with an antioxidant to improve sensitivity to low-linear-energy-transfer (LET) particles. We irradiated these detectors with various heavy ions (from protons to krypton) with various energies (30–500 MeV/u) at the heavy ion accelerator facilities in the National Institute of Radiological Sciences (NIRS). The surface roughness after chemical etching was improved to be 59% of that of the conventional high-sensitivity CR-39 detector (HARZLAS/TD-1). The detectable dynamic range of LET was found to be 3.5–600 keV/μm. The LET and charge resolutions for three ions tested ranged from 5.1% to 1.5% and 0.14 to 0.22 c.u. (charge unit), respectively, in the LET range of 17–230 keV/μm, which represents an improvement over conventional products (HARZLAS/TD-1 and BARYOTRAK). A correction factor for the angular dependence was determined for correcting the LET spectrum in an isotropic radiation field. We have demonstrated the potential of TechnoTrak, with its two key features of high surface quality and high sensitivity to low-LET particles, to improve automatic analysis protocols in radiation dosimetry and various other radiological applications.

  11. Studies on nitrogen mapping by various CR-39 track detectors

    Energy Technology Data Exchange (ETDEWEB)

    Somogyi, G.; Varga, Zs.; Hunyadi, I.; Freyer, K.; Treutler, H.Ch.

    1986-01-01

    The use of CR-39 track detectors for nitrogen distribution measurements via the /sup 14/N(n,p)/sup 14/C reaction is studied. The proton detection properties of different CR-39 products have been analyzed. The variation of background track density induced in the bulk of detectors is examined under different conditions of neutron irradiation. Analysis of our experimental data has led to the conclusion that the sources of proton background tracks are the fast neutron component of the neutron source, chlorine impurities in the detector and nitrogen diffused from the air into the upper layer of the detector. Efforts have been made to decrease the nitrogen content of diffusion origin by removing the upper detector layer and by outgassing the CR-39 sheet in vacuum before irradiation. Finally the ''signal/noise'' ratio for a steel specimen and the sensitivity of nitrogen determination are given.

  12. An electrochemical study of U(VI) and Cr(VI) in molten borates

    International Nuclear Information System (INIS)

    Brigaudeau, M.; Gregori de Pinochet, I. de

    1977-01-01

    The electrochemical reduction of U(VI) and Cr(VI), in molten Na 2 B 4 O 7 at 800 deg C was studied by means of linear sweep voltammetry, and chronopotentiometry. The reduction of U(VI) to U(V) proceeded reversibly at a platinum electrode. The diffusion coefficient for the U(VI) species at 800 deg C was 4.10 -7 cm 2 .s -1 . The activation energy of diffusion was (34,8 +- 0,8) kcal. mole -1 . Electrochemical studies of Cr(VI) at 800 0 C reveal a two-step reduction process at a platinum electrode. Only the voltammogram for the first step charge transfer process was studied. Analysis indicated that Cr(VI) is reversibly reduced to Cr(III) at a platinum electrode. The diffusion coefficient for Cr(VI) at 800 0 C is 1,9.10 -7 cm 2 .s -1 [fr

  13. Calculation of thermal effects occuring during the manufacture of CR-39 sheets

    Energy Technology Data Exchange (ETDEWEB)

    Szilagyi, S.; Somogyi, G.

    1984-01-01

    To manufacture a good-quality, uniform CR-39 track detector, the polymerization rate should be below a critical value to avoid the development of undesirable thermal gradients and internal temperature fluctuations in the sheet being cast. To improve curing cycles a computer program was developed to study the trends of thermal effects under different casting conditions. These calculations are based on the solution of the one-dimensional heat transport equation and take into account the relations proposed by Dial et. al. for describing the chemical kinetics of CR-39 polymerization. The authors have revised the empirical parameters available to such calculations. With new ''Dial constants'' they have calculated the critical initial bath temperature (which results in thermal runaway at the central plane of the sheet being cast) as a function of the CR-39 thickness and IPP initiator concentration. Results are also presented for the temperature profile in the depth of cast CR-39 sheets.

  14. Note: Fast neutron efficiency in CR-39 nuclear track detectors

    Energy Technology Data Exchange (ETDEWEB)

    Cavallaro, S. [Dipartimento di Fisica ed Astronomia,Università di Catania, Via S. Sofia 44, 95123 Catania, Italy and INFN-LNS, Via S. Sofia 42, 95123 Catania (Italy)

    2015-03-15

    CR-39 samples are commonly employed for fast neutron detection in fusion reactors and in inertial confinement fusion experiments. The literature reported efficiencies are strongly depending on experimental conditions and, in some cases, highly dispersed. The present note analyses the dependence of efficiency as a function of various parameters and experimental conditions in both the radiator-assisted and the stand-alone CR-39 configurations. Comparisons of literature experimental data with Monte Carlo calculations and optimized efficiency values are shown and discussed.

  15. Measurement of D-3He proton yield with CR-39 as a diagnostic for inertial confinement fusion experiments. Final report, 7 January 1983-30 September 1984

    International Nuclear Information System (INIS)

    Blue, T.E.; Wehring, B.W.

    1985-04-01

    The first phase of our research project has as its main goal the development of an image analysis system for Solid State Nuclear Track Detectors (SSNTD) readout. Section I, of this report is an introduction to SSNTDs and image analysis systems for automatic track counting. The development of the image analysis system is described in Section II. The development of our foil holder system is described in Section III. The performance of an image analysis system can only be judged with respect to a particular type of image which is to be analyzed. In order to insure the workability of our image analysis system in analyzing CR-39 SSNTDs, we have made an effort to improve our etching system and our etch procedure. The development of our etching system and our etch procedure is outlined in Section IV. Also included in Section IV are images of protons and alpha particle tracks for our etch procedure. The performance of our image analysis system is reported in Section V for the proton and alpha particle tracks which are reported in Section IV. Also, the performance of the image analysis system is reported for some test images

  16. Proton an alpha detections by track recording technique in CR-39

    International Nuclear Information System (INIS)

    Oliveira, W.A. de; Franco, M.A.R.; Herdade, S.B.; Khouri, M.C.F.; Goncalez, O.L.

    1986-07-01

    The plastic CR-39 is utilized as proton track detector in the study of the reaction 27 A (e, p) and 59 Co (e, p), near threshold. Preliminary results are presented for the energy calibration (mean track diameter as a function of proton energy) of CR-39 with mono-energetic protons of a Van de Graaff accelerator, in the energy range 1-3 MeV. (author) [pt

  17. Effect of radiation on the electrical properties of plastic detector CR-39

    International Nuclear Information System (INIS)

    Mahmoud, S.A.; Hamed, A.E.; Abou El-Kier, A.A.; Mousse, M.G.; Kassem, M.E.; El-Shafey, E.M.

    1994-01-01

    The effect of high alpha-particle fluence on plastic detector CR-39 was studied by measuring the electrical properties of the detector as a function of irradiation dose and frequency using an impedance meter in the frequency range 0.005-500 kHz. When the plastic detector CR-39 is exposed to high irradiation doses, it loses its advantage as a track detector, because of the overlapping of the tracks occurring in the detector at high irradiation fluence. Through the present measurements of dielectric permittivity and conductivity at different frequencies and temperatures, CR-39 could be used as a dosimeter for high irradiation doses

  18. Effect of radiation on the electrical properties of plastic detector CR-39

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoud, S.A.; Hamed, A.E.; Abou El-Kier, A.A.; Mousse, M.G.; Kassem, M.E.; El-Shafey, E.M. (Physics Department Faculty of Science, Alexandria University, Alexandria (Egypt))

    1994-10-15

    The effect of high alpha-particle fluence on plastic detector CR-39 was studied by measuring the electrical properties of the detector as a function of irradiation dose and frequency using an impedance meter in the frequency range 0.005-500 kHz. When the plastic detector CR-39 is exposed to high irradiation doses, it loses its advantage as a track detector, because of the overlapping of the tracks occurring in the detector at high irradiation fluence. Through the present measurements of dielectric permittivity and conductivity at different frequencies and temperatures, CR-39 could be used as a dosimeter for high irradiation doses.

  19. Ablation and cone formation mechanism on CR-39 by ArF laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Shakeri Jooybari, B., E-mail: baninshakery@gmail.com, E-mail: hafarideh@aut.ac.ir [Department of Energy Engineering and Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Nuclear Science and Technology Research Institute NSRT, Tehran (Iran, Islamic Republic of); Afarideh, H., E-mail: baninshakery@gmail.com, E-mail: hafarideh@aut.ac.ir [Department of Energy Engineering and Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); Lamehi-Rachti, M. [Nuclear Science and Technology Research Institute NSRT, Tehran (Iran, Islamic Republic of); Ghergherehchi, M. [Department of Energy Engineering and Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran, Islamic Republic of Iran (Iran, Islamic Republic of); College of Information and Communication Engineering, Sungkyunkwan University, Suwon (Korea, Republic of)

    2015-03-07

    In this work, chemical properties, surface modification, and micro structures formation on ablated polyallyl di-glycol carbonate (CR-39) polymer by ArF laser irradiation (λ = 193 nm) at various fluences and pulse number were investigated. CR-39 samples have been irradiated with an ArF laser (193 nm) at a repetition rate of 1 Hz. Threshold fluence of ablation and effective absorption coefficient of CR-39 were determined. Conical microstructures (Taylor cone) formed on laser-ablated CR-39 exhibit: smooth, Taylor cone shape walls and sharp tips together with interference and well defined fringe-structure with a period of 230 nm, around cone base. Mechanism of cone formation and cone evolution of CR-39 ablated surface were investigated by change of fluences (at a given pulse number) and pulse number (at a given fluence). Cone height, cone base, and region of interface were increased in micrometer steps by increasing the total fluence. Depression on the base of the cone and the circular fringe were simulated. FTIR spectra were measured and energy dispersive x-ray analysis of irradiated and un-irradiated samples was performed.

  20. Measurement of low neutron fluences with polycarbonate foils electrochemically etched with methyl alcohol-KOH solution

    International Nuclear Information System (INIS)

    Kumamoto, Y.

    1982-01-01

    Electrochemical etching of polycarbonate foils was performed using a KOH solution with a high concentration of methyl alcohol under different conditions of field strength, frequency, temperature and etching time. These studies showed that the highest neutron sensitivity relative to the inherent background in the foil was obtained under the following etching conditions: 52 kV/cm, 1 kHz, 30 0 C, 30 min in a solution of 45 gm KOH + 80 cc CH 3 OH + 20 cc H 2 O. Under these conditions, 100 mrem of neutrons from a Ra-Be source gave 70 pits per cm 2 while background was 7 +- 3 pits per cm 2 (10 +- 5 mrem). The pit diameters were about 90 μm. This sensitivity (giving lowest measurable dose of 15 mrem) is quite sufficient for personnel neutron dosimetry applications and the size of the pits is large enough for easy counting using a microscope at magnification of 40X. (author)

  1. Diamond growth on Fe-Cr-Al alloy by H2-plasma enhanced graphite etching

    International Nuclear Information System (INIS)

    Li, Y. S.; Hirose, A.

    2007-01-01

    Without intermediate layer and surface pretreatment, adherent diamond films with high initial nucleation density have been deposited on Fe-15Cr-5Al (wt. %) alloy substrate. The deposition was performed using microwave hydrogen plasma enhanced graphite etching in a wide temperature range from 370 to 740 degree sign C. The high nucleation density and growth rate of diamond are primarily attributed to the unique precursors used (hydrogen plasma etched graphite) and the chemical nature of the substrate. The improvement in diamond adhesion to steel alloys is ascribed to the important role played by Al, mitigation of the catalytic function of iron by suppressing the preferential formation of loose graphite intermediate phase on steel surface

  2. Feasibility study of extremity dosemeter based on polyallyl-diglycol-carbonate (CR-39) for neutron exposure

    International Nuclear Information System (INIS)

    Chau, Q.; Bruguier, P.

    2007-01-01

    In nuclear facilities, some activities such as reprocessing, recycling and production of bare fuel rods expose the workers to mixed neutron-photon fields. For several workplaces, particularly in glove boxes, some workers expose their hands to mixed fields. The mastery of the photon extremity dosimetry is relatively good, whereas the neutron dosimetry still raises difficulties. In this context, the Inst. for Radiological Protection and Nuclear Safety (IRSN) has proposed a study on a passive neutron extremity dosemeter based on chemically etched CR-39 (PADC: polyallyl-diglycol-carbonate), named PN-3, already used in routine practice for whole body dosimetry. This dosemeter is a chip of plastic sensitive to recoil protons. The chemical etching process amplifies the size of the impact. The reading system for tracks counting is composed of a microscope, a video camera and an image analyser. This system is combined with the dose evaluation algorithm. The performance of the dosemeter PN-3 has been largely studied and proved by several laboratories in terms of passive individual neutron dosemeter which is used in routine production by different companies. This study focuses on the sensitivity of the extremity dosemeter, as well as its performance in the function of the level of the neutron energy. The dosemeter was exposed to monoenergetic neutron fields in laboratory conditions and to mixed fields in glove boxes at workplaces. (authors)

  3. Electrochemical Behavior and Hydrophobic Properties of CrN and CrNiN Coatings in Simulated Proton Exchange Membrane Fuel Cell Environment

    Directory of Open Access Journals (Sweden)

    JIN Jie

    2016-10-01

    Full Text Available The CrN and CrNiN coatings were prepared on the surface of 304 stainless steel by closed field unbalanced magnetron sputtering.X ray diffraction and field emission scanning electron microscopy were used to characterize the structure and morphology of the coatings.The electrochemical corrosion properties under the simulated proton exchange membrane fuel cell(PEMFC environment, interfacial contact resistance and hydrophobic properties of the two kinds of different coatings were investigated by electrochemical methods,contact resistance test and hydrophobic test,respectively.The results indicate that CrN coating mainly consists of CrN and Cr2N phase,CrN and Cr2N phases in the CrNiN coating are less compared to CrN film, and Ni exist as element in CrNiN coating; dynamic polarization tests show the coating is of better corrosion resistance,whereas the corrosion resistance of CrNiN coating is worse than that of CrN coating,constant potential polarization test shows the corrosion current density of CrN and CrNiN coatings are equivalent; CrN and CrNiN coatings significantly reduce the interfacial contact resistance of the 304 stainless steel,among which CrN coating has the smallest contact resistance; and CrNiN coating which has better hydrophobicity than that of CrN coating is more beneficial for the water management in proton exchange membrane fuel cell.

  4. Sensitivity determination of CR-39 from Normal and inclined incidence

    International Nuclear Information System (INIS)

    Abou, A.A.; El-Kheir, A.A.; Daas, A.F.; Awwad, Z.; Reda, A.M.

    2000-01-01

    An experimental study have been carried out on alpha- particle track opening (Major and minor axes) using alpha-particles of different energies incident with different angels in addition to the normal incidence. The sensitivity of CR-39 in present work is determined for each of normal and inclined incidence. The results indicated a difference in the sensitivity according to angle of incidence. The variation of alpha- particle tracks (major and minor axes) are calculated and compared with our measured values. Also, it is found that the sensitivity of CR-39 detector is change due to the storage time at room temperature

  5. Calibration of CR-39 for radon-related parameters using sealed cup technique

    International Nuclear Information System (INIS)

    Abo-Elmagd, M.; Daif, M. M.

    2010-01-01

    Effective radium content, mass and areal radon exhalation rates of soil and rock samples are important radon-related parameters and can be used as a better indicator of radon risk. A sealed cup fitted to a CR-39 detector and to the sample under measurement is an advantageous passive device for the measurement of these parameters. The main factors affecting the results are the detector calibration factor and the sample weight. The results of an active technique (Lucas cell) and the CR-39 detector have been found to be correlated resulting in a reliable detector calibration factor. The result illustrates the dependence of the CR-39 calibration factor with the sample weight which is difficult to use in practice, because each sample weight has its own calibration factor of CR-39. It is reported to demonstrate the advantage of a back diffusion correction. After correcting the results for back diffusion effects, one obtains an approximately constant calibration factor for the sample volumes up to one-third the total sealed cup volume. For this condition the calibration factor is equal to 0.237 track cm -2 per Bq m -3 d with about 1% uncertainty. (authors)

  6. Range energy for heavy ions in CR-39

    International Nuclear Information System (INIS)

    Gil, L.R.; Marques, A.

    1987-01-01

    Range-energy relations in CR-39, for ions from He to Ar, are obtained after their effective nuclear charge. Comparison with earlier calculations and numerical results in the energy range 0,1 to 200 Mev/ Nucleon are also given. (M.W.O.)

  7. Electrochemical trench etching of silicon triggered via mechanical nanocontacts

    Energy Technology Data Exchange (ETDEWEB)

    Gassilloud, R.; Michler, J. [EMPA, Materials Science and Technology, Feuerwerkerstrasse 39, CH-3602 Thun (Switzerland); Schmuki, P. [Department of Materials Science, LKO, University of Erlangen-Nuernberg, Martensstrasse 7, D-91058 Erlangen (Germany)

    2007-12-01

    We report a method to produce microstructures on silicon wafers using a microscratching technique followed by a subsequent electrochemical trench etching in hydrofluoric-based electrolyte. Micro-scratches are used to trigger macropore formation. We show that mask-less dissolved trenches with aspect ratios up to 1:7 are formed at the scratched regions on (0 0 1)Si surface. The micro-scratches orientate the macropores formation by aligning them in the scratching direction. We propose that dislocations formed during scratching are firstly dissolved leading to the formation of V-shape grooves. The V-shape geometries obtained by this way are used to initiate the macropores nucleation; i.e. due to the geometry, an avalanche current occurs at the grooves base and thus induces local dissolutions of the substrate. High rate local dissolutions are achieved by back-side illumination of the Si wafer. (author)

  8. Alpha particle spectroscopy for CR-39 detector utilizing matrix of energy equations

    Energy Technology Data Exchange (ETDEWEB)

    Awad, E.M. [Department of General Sciences, Yanbu Industrial College, PO Box 30436, Madinat Yanbu Al-Sinaiya (Saudi Arabia); Physics Department, Faculty of Science, Menofia University, Shebin El-Koom (Egypt)], E-mail: ayawad@yahoo.com; Soliman, A.A. [Department of Mathematics, Faculty of Education (AL-Arish), Suez Canal University, AL-Arish 45111 (Egypt); Department of Mathematics, Teacher' s College (Bisha), King Khalid University, Bisha, PO Box 551 (Saudi Arabia)], E-mail: asoliman_99@yahoo.com; Rammah, Y.S. [Physics Department, Faculty of Science, Menofia University, Shebin El-Koom (Egypt)

    2007-10-01

    A method for determining alpha-particle energy using CR-39 detector by utilizing matrix of energy equation was described. The matrix was composed from two axes; the track minor axis (m) and diameter of etched out track end (d) axis of some selected elliptical tracks. The energy E in (m,d) coordinate was approximated by matrix of energy equations given by: E{sub k}={sigma}{sub i,j=0}{sup 2}a{sub ij}d{sub k}{sup i}m{sub k}{sup j}, which was identified using two different approaches. First, i and j were treated as power exponents for d and m. The adjusting parameters values a{sub ij} were obtained and the energy of a given track was deduced directly from it. Second, i and j were treated as indices of some chosen tracks that were fitted to obtain iso-energy curves that were superimposed on m-d scatter plot as calibration curves. The energy between any two successive iso-energy curves in this case was assumed varied linearly with d for a given m. The energy matrix in both cases was solved numerically. Results of the two approaches were compared.

  9. Application of CR-39 microfilm for rapid discrimination between alpha-particle sources

    Energy Technology Data Exchange (ETDEWEB)

    Dwaikat, Nidal; Al-karmi, Anan M. [Dept. of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

    2017-06-15

    This work presents a new technique for discriminating between alpha particles of different energy levels. In a first study, two groups of alpha particles emitted from radium-226 and americium-241 sources were successfully separated using a CR-39 microfilm of appropriate thickness. This thickness was adjusted by chemical etching before and after irradiation so that lower-energy particles were stopped within the detector, while higher-energy particles were revealed on the back side of the detector. The number of tracks on the front side of the microfilm represented all alpha particles incident on that side from the two sources. However, the number of tracks on the back side of the microfilm represented only the long-range alpha particles of higher energy that arrived at that side. Therefore, by subtracting the number of tracks on the back side from the number of tracks on the front side, one could easily determine the number of tracks for the short-range alpha particles of lower energy that remained embedded in the microfilm. Discrimination of the two energy levels is thus achieved in a simple, fast, and reliable process.

  10. Effects of UV light intensity on electrochemical wet etching of SiC for the fabrication of suspended graphene

    Science.gov (United States)

    O, Ryong-Sok; Takamura, Makoto; Furukawa, Kazuaki; Nagase, Masao; Hibino, Hiroki

    2015-03-01

    We report on the effects of UV light intensity on the photo assisted electrochemical wet etching of SiC(0001) underneath an epitaxially grown graphene for the fabrication of suspended structures. The maximum etching rate of SiC(0001) was 2.5 µm/h under UV light irradiation in 1 wt % KOH at a constant current of 0.5 mA/cm2. The successful formation of suspended structures depended on the etching rate of SiC. In the Raman spectra of the suspended structures, we did not observe a significant increase in the intensity of the D peak, which originates from defects in graphene sheets. This is most likely explained by the high quality of the single-crystalline graphene epitaxially grown on SiC.

  11. New possibility for high-resolution spectroscopy of nuclear particles entering CR-39 at selected dip angles

    Energy Technology Data Exchange (ETDEWEB)

    Somogyi, G.; Hunyadi, I.; Hafez, A.F. (Magyar Tudomanyos Akademia, Debrecen. Atommag Kutato Intezete); Espinosa, G. (Universidad Nacional Autonoma de Mexico, Mexico City. Inst. de Fisica)

    1984-01-01

    In nuclear reaction studies a differentiation of the reaction products according to their type and energy is generally required. At right angle of incidence a particle identification method based on the relation between the track diameter and particle energy can be well applied to plastic track detectors of low registration sensitivity. We have tried to extend this 'track-diameter method' to the high-sensitivity CR-39 sheets by selecting special incident angles for particle detection. The utility of such a measuring procedure, called 'track-size method', is presented for alpha and proton spectroscopy. A theory is developed to calculate at arbitrary angles the main parameters affecting the energy resolving power of the 'track-size method', namely the critical layer thickness (which has to be removed from the detector surface for track-induction) and the depth and minor axis of etch-pits.

  12. Removal of Cr(VI) from wastewaters at semi-industrial electrochemical reactors with rotating ring electrodes

    International Nuclear Information System (INIS)

    Rodriguez R, Miriam G.; Mendoza, Victor; Puebla, Hector; Martinez D, Sergio A.

    2009-01-01

    In Mexico, most of the electroplating and textile industries are small facilities and release relatively large amounts of hexavalent chromium (Cr(VI)) in surface waters. In this work, the results obtained during the operation of a batch reactor with a capacity of 170 L, and three electrochemical flow reactors-in-series system with a total capacity of 510 L (both using iron rotating ring electrodes to remove Cr(VI) from wastewaters) are presented. The reactors were scaled up from a laboratory reactor to a semi-industrial level, based on the similarity (dynamical, geometrical and electrochemical). An empirical Cr(VI) removal model was validated in batch and continuous reactors at different operating conditions. Cr(VI) concentration of the industrial wastewaters was reduced from about 500 mg/L to values lower than 0.5 mg/L. A very important parameter that affects the process is the pH, which affects the solubility of the Fe(III). Finally, the electrochemical treated wastewater can be reused

  13. Removal of Cr(VI) from wastewaters at semi-industrial electrochemical reactors with rotating ring electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez R, Miriam G. [Depto. Energia, Universidad Autonoma Metropolitana-Azcapotzalco, Av. San Pablo 180, Azcapotzalco, CP 07740, Mexico D.F. (Mexico); Mendoza, Victor [Depto. Electronica, Universidad Autonoma Metropolitana-Azcapotzalco, Av. San Pablo 180, Azcapotzalco, CP 07740, Mexico D.F. (Mexico); Puebla, Hector [Depto. Energia, Universidad Autonoma Metropolitana-Azcapotzalco, Av. San Pablo 180, Azcapotzalco, CP 07740, Mexico D.F. (Mexico); Martinez D, Sergio A. [Depto. Energia, Universidad Autonoma Metropolitana-Azcapotzalco, Av. San Pablo 180, Azcapotzalco, CP 07740, Mexico D.F. (Mexico)], E-mail: samd@correo.azc.uam.mx

    2009-04-30

    In Mexico, most of the electroplating and textile industries are small facilities and release relatively large amounts of hexavalent chromium (Cr(VI)) in surface waters. In this work, the results obtained during the operation of a batch reactor with a capacity of 170 L, and three electrochemical flow reactors-in-series system with a total capacity of 510 L (both using iron rotating ring electrodes to remove Cr(VI) from wastewaters) are presented. The reactors were scaled up from a laboratory reactor to a semi-industrial level, based on the similarity (dynamical, geometrical and electrochemical). An empirical Cr(VI) removal model was validated in batch and continuous reactors at different operating conditions. Cr(VI) concentration of the industrial wastewaters was reduced from about 500 mg/L to values lower than 0.5 mg/L. A very important parameter that affects the process is the pH, which affects the solubility of the Fe(III). Finally, the electrochemical treated wastewater can be reused.

  14. Fabrication of Metallic Microneedle by Electroplating and Sharpening of it by Electrochemical Etching

    Science.gov (United States)

    Huang, Chih-Hao; Tanaka, Takahiro; Takaoki, Yutaka; Izumi, Hayato; Takahashi, Tomokazu; Suzuki, Masato; Aoyagi, Seiji

    Aiming at the use in low-invasive medical treatments, this paper reports a fabrication of metallic microneedle, which has a three-dimensionally sharp tip. Compared to a silicon or polymer needle which we previously proposed, a metallic needle has toughness to evade breakage. Even if it is broken, it does not become small pieces thanks to its ductility, which increases the safety for a human body. A nickel needle was fabricated using electroplating, followed by sharpening it by electrochemical etching. A smooth tip surface is obtained due to electrochemical etching reactions. Sharpness and smoothness of the tip are effective for easy insertion in the viewpoint of large stress concentration and small friction, respectively. An experiment of inserting the fabricated needle into an artificial skin of silicone rubber was carried out. The resistance force during insertion was much reduced compared to that of commercial stainless needle (23 G: shank diameter 650 µm). Although a fabricated metallic needle was inserted and pulled-out for several times, it was not broken in any trial. By changing the angle between object surface and needle axis, the insertion experiments were carried out. Fabricated nickel needle was not broken for any angle, while silicon needle was broken in case the angle is small, i.e., the needle is much inclined from normal direction of the surface, which ensures the safety of metallic microneedle to human body in the viewpoint of breakage.

  15. Cryogenic Etching of High Aspect Ratio 400 nm Pitch Silicon Gratings.

    Science.gov (United States)

    Miao, Houxun; Chen, Lei; Mirzaeimoghri, Mona; Kasica, Richard; Wen, Han

    2016-10-01

    The cryogenic process and Bosch process are two widely used processes for reactive ion etching of high aspect ratio silicon structures. This paper focuses on the cryogenic deep etching of 400 nm pitch silicon gratings with various etching mask materials including polymer, Cr, SiO 2 and Cr-on-polymer. The undercut is found to be the key factor limiting the achievable aspect ratio for the direct hard masks of Cr and SiO 2 , while the etch selectivity responds to the limitation of the polymer mask. The Cr-on-polymer mask provides the same high selectivity as Cr and reduces the excessive undercut introduced by direct hard masks. By optimizing the etching parameters, we etched a 400 nm pitch grating to ≈ 10.6 μ m depth, corresponding to an aspect ratio of ≈ 53.

  16. The study of optimal conditions of electrochemical etching of tunnel electron microscopy tungsten tips

    International Nuclear Information System (INIS)

    Anguiano, E.; Aguilar, M.; Olivar, A.I.

    1996-01-01

    We present the experimental results obtained during the study made in the electrochemical etching of tunneling electron microscopy tungsten tips. The experiments was made using DC and two usual electrolytes: KOH and NaOH. For the tip preparation we used a electrochemical cell with stainless steel cathode and the tungsten wire as anode. the electrodes was introduced in a glass recipient containing the electrolytic solution. We study the effects of applied voltage, polish time, tip length and electrolyte concentration as process relevant parameters. The best condition for tip preparation was obtained with a metallurgical microscope and with a SEM.EDX and Auger analysis was made. The results shown the better tips was made with KOH as electrolyte with a limited concentration range (2-4 normal) and applied voltage (2-6 volts) (Author) 20 refs

  17. Chemical etching of stainless steel 301 for improving performance of electrochemical capacitors in aqueous electrolyte

    Science.gov (United States)

    Jeżowski, P.; Nowicki, M.; Grzeszkowiak, M.; Czajka, R.; Béguin, F.

    2015-04-01

    The main purpose of the study was to increase the surface roughness of stainless steel 301 current collectors by etching, in order to improve the electrochemical performance of electrical double-layer capacitors (EDLC) in 1 mol L-1 lithium sulphate electrolyte. Etching was realized in 1:3:30 (HNO3:HCl:H2O) solution with times varying up to 10 min. For the considered 15 μm thick foil and a mass loss around 0.4 wt.%, pitting was uniform, with diameter of pits ranging from 100 to 300 nm. Atomic force microscopy (AFM) showed an increase of average surface roughness (Ra) from 5 nm for the as-received stainless steel foil to 24 nm for the pitted material. Electrochemical impedance spectroscopy realized on EDLCs with coated electrodes either on as-received or pitted foil in 1 mol L-1 Li2SO4 gave equivalent distributed resistance (EDR) of 8 Ω and 2 Ω, respectively, demonstrating a substantial improvement of collector/electrode interface after pitting. Correlatively, the EDLCs with pitted collector displayed a better charge propagation and low ohmic losses even at relatively high current of 20 A g-1. Hence, chemical pitting of stainless steel current collectors is an appropriate method for optimising the performance of EDLCs in neutral aqueous electrolyte.

  18. Fabrication and characterization of a nanometer-sized optical fiber electrode based on selective chemical etching for scanning electrochemical/optical microscopy.

    Science.gov (United States)

    Maruyama, Kenichi; Ohkawa, Hiroyuki; Ogawa, Sho; Ueda, Akio; Niwa, Osamu; Suzuki, Koji

    2006-03-15

    We have already reported a method for fabricating ultramicroelectrodes (Suzuki, K. JP Patent, 2004-45394, 2004). This method is based on the selective chemical etching of optical fibers. In this work, we undertake a detailed investigation involving a combination of etched optical fibers with various types of tapered tip (protruding-shape, double- (or pencil-) shape and triple-tapered electrode) and insulation with electrophoretic paint. Our goal is to establish a method for fabricating nanometer-sized optical fiber electrodes with high reproducibility. As a result, we realized pencil-shaped and triple-tapered electrodes that had radii in the nanometer range with high reproducibility. These nanometer-sized electrodes showed well-defined sigmoidal curves and stable diffusion-limited responses with cyclic voltammetry. The pencil-shaped optical fiber, which has a conical tip with a cone angle of 20 degrees , was effective for controlling the electrode radius. The pencil-shaped electrodes had higher reproducibility and smaller electrode radii (r(app) etched optical fiber electrodes. By using a pencil-shaped electrode with a 105-nm radius as a probe, we obtained simultaneous electrochemical and optical images of an implantable interdigitated array electrode. We achieved nanometer-scale resolution with a combination of scanning electrochemical microscopy SECM and optical microscopy. The resolution of the electrochemical and optical images indicated sizes of 300 and 930 nm, respectively. The neurites of living PC12 cells were also successfully imaged on a 1.6-microm scale by using the negative feedback mode of an SECM.

  19. Identification of charged particles by etching the solid state nuclear track detectors in successive intervals

    International Nuclear Information System (INIS)

    Randhawa, G.S.; Virk, H.S.

    1997-01-01

    The suitability of the method of charged particle identification by etching the samples in successive intervals developed by Grabez et al. has been checked in CR-39 exposed to heavy ions 238 U, 208 Pb, 197 Au and 132 Xe in the interval 11.0 to 17.0 MeV/u. A similar study has been made on soda glass detectors irradiated by 238 U, 132 Xe, 56 Fe and 48 Ti ions having energy 4.0 to 6.0 MeV/u. It is concluded that this method of particle identification can be used successfully in CR-39 and soda glass detectors. (author)

  20. Non-chapped, vertically well aligned titanium dioxide nanotubes fabricated by electrochemical etching

    Science.gov (United States)

    Loan Nguyen, Thu; Dieu Thuy Ung, Thi; Liem Nguyen, Quang

    2014-06-01

    This paper reports on the fabrication of non-chapped, vertically well aligned titanium dioxide nanotubes (TONTs) by using electrochemical etching method and further heat treatment. Very highly ordered metallic titanium nanotubes (TNTs) were formed by directly anodizing titanium foil at room temperature in an electrolyte composed of ammonium fluoride (NH4F), ethylene glycol (EG), and water. The morphology of as-formed TNTs is greatly dependent on the applied voltage, NH4F content and etching time. Particularly, we have found two interesting points related to the formation of TNTs: (i) the smooth surface without chaps of the largely etched area was dependent on the crystalline orientation of the titanium foil; and (ii) by increasing the anodizing potential from 15 V to 20 V, the internal diameter of TNT was increased from about 50 nm to 60 nm and the tube density decreased from 403 tubes μm-2 down to 339 tubes μm-2, respectively. For the anodizing duration from 1 h to 5 h, the internal diameter of each TNT was increased from ˜30 nm to 60 nm and the tube density decreased from 496 tubes μm-2 down to 403 tubes μm-2. After annealing at 400 °C in open air for 1 h, the TNTs were transformed into TONTs in anatase structure; further annealing at 600 °C showed the structural transformation from anatase to rutile as determined by Raman scattering spectroscopy.

  1. Determination of the exhalation rate of radon and thoron from building materials by detectors Cr-39

    International Nuclear Information System (INIS)

    Vasidov, A.

    2005-01-01

    Full text: The building materials (BM) such as granite, bricks, sand, cement etc., contain uranium and thorium in various amounts. Therefore the knowledge of true value exhalation rate of Rn and Tn from BM represents scientific and practical interest in environmental radiation protection. In present work, we have used calibrated plastic cups with two detectors Cr-39. The detected surface of the cup is situated in perpendicular position surface BM and were exposed for 20-30 days. The first detector fixed the bottom on distance from surface of BM and records alpha particles from Rn-222 only. The second detector records alpha particles of the thoron and radon. After exposition, the detectors chemically etched and analyzed. The values of the exhalation rate per unit area of the granite, concrete, fired and unfired bricks, sand, cement, alabaster varied 0.091 - 0.1 Bq m -2 h -1 for the radon, 200 - 5800 Bq m -2 h - 1 for the thoron, accordingly

  2. Gamma irradiation effects on the thermal, optical and structural properties of Cr-39 nuclear track detector

    International Nuclear Information System (INIS)

    Nouh, S.A.; Said, A.F.; Atta, M.R.; EL-Mellegy, W.M.; EL-Meniawi, S.

    2006-01-01

    A study of the effect of gamma irradiation on the thermal, optical and structural properties of CR-39 diglycol carbonate solid state nuclear track detector (SSNTD) has been carried out. Samples from CR-39 polymer were irradiated with gamma doses at levels between 20 and 300 KGy. Non-isothermal studies were carried out using thermo-gravimetry (TG), differential thermo-gravimetry (DTG) and differential thermal analysis (DTA) to obtain the activation energy of decomposition and the transition temperatures for the non-irradiated and irradiated CR-39 samples. In addition, optical and structural property studies were performed on non-irradiated and irradiated CR-39 samples using refractive index and X-ray diffraction measurements. The variation of onset temperature of decomposition (To) thermal activation energy of decomposition (Ea) melting temperature (Tm) refractive index (n) and the mass fraction of the amorphous phase with the gamma dose were studied. It was found that many changes in the thermal, optical and structural properties of the CR-39 polymer could be produced by gamma irradiation via the degradation and cross linking mechanisms. Also, the gamma dose gave an advantage for increasing the correlation between the thermal stability of CR-39 polymer and the bond formation created by the ionizing effect of gamma radiation

  3. A passive monitor for radon using electrochemical track etch detector

    International Nuclear Information System (INIS)

    Massera, G.E.; Hassib, G.M.; Piesch, E.

    1980-01-01

    A passive monitor for radon and its decay products based on the electrochemical etching (ECE) of α-particle tracks on Makrofol is described. The monitor has been constructed in such a way that radon and radon daughters attached to aerosols can easily pass through a chamber while dust, heavy particles and water droplets are collected outside. The decay products are accumulated on the bottom of the chamber and a Makrofol detector foil is fixed on the top to register alpha particles. The ECE condition was maintained to detect alpha particles coming mainly from radon daughters trapped on the bottom of the chamber. The response of the monitor was determined at different exposure conditions and compared with those of some active techniques such as working level meters. The merits of this system are low cost, good sensitivity, portability and reliable, unattended operation. (author)

  4. The Use Of Optical Properties Of Cr-39 In Alpha Particle Equivalent Dose Measurements

    International Nuclear Information System (INIS)

    Shnishin, K.A.

    2007-01-01

    In this work, optical properties of alpha irradiated Cr-39 were measured as a function of optical photon wavelength from 200-1100 nm. Optical energy gap and optical absorption at finite wavelength was also calculated and correlated to alpha fluence and dose equivalent. Alpha doses were calculated from the corresponding irradiation fluence and specific energy loss using TRIM computer program. It was found that, the optical absorption of unattached Cr-39 was varied with alpha fluence and corresponding equivalent doses. Also the optical energy gab was varied with fluence and dose equivalent of alpha particles. This work introduces a reasonably simple method for the Rn dose equivalent calculation by Cr-39 track

  5. Modification of Patterned Nanoporous Gold Thin Film Electrodes via Electro-annealing and Electrochemical Etching

    Science.gov (United States)

    Dorofeeva, Tatiana

    current to np-Au electrodes, which leads coarsening due to a combination of Joule heating and other mechanisms. This method offers the capability to anneal different electrodes to varying degrees of coarsening in one step, by employing electrodes patterns with different cross-sectional areas - easily attained since np-Au can be patterned into arbitrary shapes via photolithography - to control electrode resistivity, thus current density and the amount of electro-annealing of an electrode. A surprising finding was that electro-annealing lead to electrode coarsening at much lower temperatures than conventional thermal treatment, which was attributed to augmented electron-surface atom interactions at high current densities that may in turn enhance surface atom diffusivity. A major advantage of electro-annealing is the ability to monitor the resistance change of the electrode (surrogate for electrode morphology) in real-time and vary the electro-annealing current accordingly to establish a closed-loop electro-annealing configuration. In nanostructured materials, the electrical resistance is often a function of nanostructure, thus changes in resistance can be directly linked to morphological changes of the electrode. Examination of the underlying mechanisms of nanostructure-dependent resistance change revealed that both ligament diameter and grain size play a role in dictating the observed electrode resistance change. The second method relies on electrochemical etching of ligaments to modify electrode morphology in order to maintain both a high effective surface area and large pores for unhindered transport of molecules to/from the ligament surfaces - an important consideration for many physico-chemical processes, such fuel cells, electrochemical sensors, and drug delivery platforms. The advantage of this method over purely chemical approach is that while an entire sample in exposed to the chemical reagent, the etching process does not occur until the necessary electrochemical

  6. Practical consequences for the use of a personal dosimeter for fast neutrons based on CR39 exposed up to one year

    International Nuclear Information System (INIS)

    Boschung, Markus; Fiechtner, Annette; Mayer, Sabine; Wernli, Christian

    2008-01-01

    Full text: At the Paul Scherrer Institut a personal neutron dosimetry system based on chemically etched CR-39 detectors and automatic track counting is in routine use since 1998. In its original design, the dosimeter is sensitive to thermal neutrons and to neutrons in the energy range from 200 keV up to several MeV. The standard exposition period is 3 months. Recently, a novel concept for individual monitoring was implemented at CERN. In this concept, each worker who possibly enters a radiation zone is equipped with a combined dosimeter for the measurement of personal photon and neutron doses. The dosimeter for photon dose measurement has an instant readout capability and dose measurements are done monthly. The dosimeter for neutron measurement is based on CR-39 detectors and is sensitive to fast neutrons only. The CR-39 detector is only evaluated and a neutron dose determined if the monthly personal photon dose exceeds 2 mSv or if the exposition period of the neutron dosimeter exceeds one year. This novel regime of use of the neutron dosimeter has had some important consequences for its practical implementation. A priori, the wearing period of a neutron dosimeter is not known and can range from 1 month up to 12 or even more months. A good knowledge of the long-term behaviour and characteristics of the detector material is needed. But also organisational and administrative issues have to be considered. The paper will outline the adopted procedure covering not only technical but also organisational aspects. The long-term behaviour of background track density and response to 241 Am-Be over one year are described as well as calibrations performed with 241 Am-Be and 252 Cf sources and in the High-Energy Reference Field Facility at CERN (CERF). The concept of individual monitoring at CERN could be transferred to other locations with high energy accelerators such as PSI and DESY. The experience gained with the neutron dosimeter based on CR-39 since introduction of the

  7. Luminescence evolution of porous GaN thin films prepared via UV-assisted electrochemical etching

    International Nuclear Information System (INIS)

    Cheah, S.F.; Lee, S.C.; Ng, S.S.; Yam, F.K.; Abu Hassan, H.; Hassan, Z.

    2015-01-01

    Porous gallium nitride (GaN) thin films with different surface morphologies and free carriers properties were fabricated from Si-doped GaN thin films using ultra-violet assisted electrochemical etching approach under various etching voltages. Fluctuation of luminescence signals was observed in the photoluminescence spectra of porous GaN thin films. Taking advantage of the spectral sensitivity of infrared attenuated total reflection spectroscopy on semiconductor materials, roles of free carriers and porous structure in controlling luminescence properties of GaN were investigated thoroughly. The results revealed that enhancement in luminescence signal is not always attained upon porosification. Although porosification is correlated to the luminescence enhancement, however, free carrier is the primary factor to enhance luminescence intensity. Due to unavoidable significant reduction of free carriers from Si-doped GaN in the porosification process, control of etching depth (i.e., thickness of porous layer formed from the Si-doped layer) is critical in fabricating porous GaN thin film with enhanced luminescence response. - Highlights: • Various pore morphologies with free carrier properties are produced by Si-doped GaN. • Free carriers are important to control the luminescence signal of porous GaN. • Enhancement of luminescence signal relies on the pore depth of Si-doped layer

  8. Fission studies of gold induced by (1665 MeV) π- using a CR-39 detector

    International Nuclear Information System (INIS)

    Muhammad Ikram Shahzad; Yasin, Zafar; Sher, Gul

    2012-01-01

    The fission cross section and fission probability of 197 Au, induced by (1665 MeV) π'-, have been studied using CR-39 track detectors. A 4π-geometry was used to count track statistics. A beam of negative pions of 1665 MeV was produced at AGS of Brookhaven National Laboratory, USA, and allowed to fall normally on the stack. Two detectors from the stack were scanned for fission fragment tracks after etching in 6N NaOH at 70 ℃. The statistics of fission fragment tracks in both detectors were obtained. It was found that there was a marked asymmetry of registered tracks with respect to the forward and backward hemispheres. This asymmetry could be partly accounted for on the basis of momentum transfer to the struck nucleus. On the basis of counting statistics fission cross section was measured, and fission probability was determined by dividing the fission cross section with the reaction cross section. The fission cross-section and fission probability were compared with the computed values using the cascade-exciton model code CEM95. (authors)

  9. Energy response study of modified CR-39 neutron personnel dosimeter

    International Nuclear Information System (INIS)

    Sathian, Deepa; Bakshi, A.K.; Datta, D.; Nair, Sreejith S.; Sathian, V.; Mishra, Jitendra; Sen, Meghnath

    2018-01-01

    Personnel neutron dosimetry is an integral part of radiation protection. No single dosimeter provides the satisfactory energy response, sensitivity, angular dependence characteristics and accuracy necessary to meet the requirement of an ideal personnel neutron dosimeter. The response of a personnel neutron dosimeter is critically dependent upon the energy distribution of the neutron field. CR-39 personnel neutron dosimeters were typically calibrated in the standard neutron field of 252 Cf and 241 Am-Be in our laboratory, although actual neutron fields may vary from the calibration neutron spectrum. Recently the badge cassette of the personnel neutron dosimeter was changed due to frequent damage of the PVC badge used earlier. This paper discusses energy response of CR-39 solid state nuclear track detector loaded in this modified badge cassette as per latest ISO recommendation

  10. Neutron dosimeter utilizing CR-39

    International Nuclear Information System (INIS)

    Souza, H.V.C. de.

    1991-05-01

    A personnel neutron dosimeter has been developed with discretization in a wide range of energies of real interest, utilizing the CR-39 polymer, to detect recoil protons in the fast range, and alpha particles in the thermal and epithermal ranges, with possibility to be disposed in the IRD/CNEN's conventional film badge suport. They are presented, abstractly, the difficulties and importance of the neutron dosimetry, beyond the general objectives that motivated this work execution. The details of the materials utilized in the dosimeter confection, and the experimental methodology employed to obtain the performance curves are presented. The results about linearity response of the dosimeter with respect to equivalent dose, in a wide range of doses, and about the verified angular dependence are analysed. (author)

  11. Enhanced Properties of Porous GaN Prepared by UV Assisted Electrochemical Etching

    International Nuclear Information System (INIS)

    Ainorkhilah Mahmood; Ainorkhilah Mahmood; Siang, C.L.

    2011-01-01

    The structural and optical properties of porous GaN films on sapphire (0001) prepared by UV assisted electrochemical etching were reported in this study. SEM micrographs indicated that the shapes of the pores for both porous samples are nearly hexagonal. XRD revealed that the broadening in spectrum is due to the small size crystallites. As compared to the as grown GaN films, porous layers exhibit a substantial photoluminescence (PL) intensity enhancement with red-shifted band-edge PL peaks associated with the relaxation of compressive stress. The shift of E2(high) to the lower frequency in Raman spectra of the porous GaN films further confirms such a stress relaxation. (author)

  12. Etching Properties of Poly ethyleneterephthalate (PET) Melinex-E Nuclear Track Detectors (NTDs)

    International Nuclear Information System (INIS)

    Ghanim, E.H.; Hussein, A.; El-samman, H.M.; Tretyakova, S.P.

    2009-01-01

    One of the main parameters that control track formation is the bulk etch rate, VB. The dependence of VB on etchant concentrations and temperatures was extensively carried out. It is found that, VB of the PET Melinex-E (C 10 H 8 O 4 ) depends upon the etchant temperature T through an Arrhenius equation. While, the dependence of VB on the etchant concentration; C followed the relation VB = A C n. The activation energy of etching, Eb, for the studied Melinex-E detector was calculated. An average value of Eb = 0.83 ± 0.03 eV was extracted. The variation of, VB, of PET with etching duration was studied and compared with that of CR-39 plastic at certain etching temperature; T e =60 degree C and at different etchant concentrations. The irradiation facilities were performed with the 252 Cf fission fragments and 129 Xe +8 (θi =π/2). Results of these studies were discussed in the frame work of nuclear track formation and etching theories

  13. Development of optical monitor of alpha radiations based on CR-39.

    Science.gov (United States)

    Joshirao, Pranav M; Shin, Jae Won; Vyas, Chirag K; Kulkarni, Atul D; Kim, Hojoong; Kim, Taesung; Hong, Seung-Woo; Manchanda, Vijay K

    2013-11-01

    Fukushima accident has highlighted the need to intensify efforts to develop sensitive detectors to monitor the release of alpha emitting radionuclides in the environment caused by the meltdown of the discharged spent fuel. Conventionally, proportional counting, scintillation counting and alpha spectrometry are employed to assay the alpha emitting radionuclides but these techniques are difficult to be configured for online operations. Solid State Nuclear Track Detectors (SSNTDs) offer an alternative off line sensitive technique to measure alpha emitters as well as fissile radionuclides at ultra-trace level in the environment. Recently, our group has reported the first ever attempt to use reflectance based fiber optic sensor (FOS) to quantify the alpha radiations emitted from (232)Th. In the present work, an effort has been made to develop an online FOS to monitor alpha radiations emitted from (241)Am source employing CR-39 as detector. Here, we report the optical response of CR-39 (on exposure to alpha radiations) employing techniques such as Atomic Force Microscopy (AFM) and Reflectance Spectroscopy. In the present work GEANT4 simulation of transport of alpha particles in the detector has also been carried out. Simulation includes validation test wherein the projected ranges of alpha particles in the air, polystyrene and CR-39 were calculated and were found to agree with the literature values. An attempt has been further made to compute the fluence as a function of the incidence angle and incidence energy of alphas. There was an excellent correlation in experimentally observed track density with the simulated fluence. The present work offers a novel approach to design an online CR-39 based fiber optic sensor (CRFOS) to measure the release of nanogram quantity of (241)Am in the environment. © 2013 Elsevier Ltd. All rights reserved.

  14. The possibility of using plastic detectors CR-39 as UV dosimeters

    International Nuclear Information System (INIS)

    Shweikani, R.; Raja, G.; Sawaf, A.A.

    2004-01-01

    The effects of solar ultraviolet (SUV) and ultraviolet type A (UVA) produced by a solar UV simulator on CR-39 detectors were studied. This was done using three techniques: 1 - Alpha tracks diameters and tracks densities, 2 - UV-Vis spectrometry and 3 - FTIR spectrometry. The detectors were divided into two groups, the first was exposed to UV and then to alpha particles, the second group was exposed to alpha particles first and then to UV. The results showed that the effect of UVA on CR-39 was not clear using the three techniques. While, the effect of SUV was clear when using UV-Vis and FTIR spectrometric, and not clear when using track parameters. (author)

  15. The possibility of using plastic detectors CR-39 as UV dosimeters

    International Nuclear Information System (INIS)

    Shweikani, R.; Raja, G.; Sawaf, A.A.

    2002-01-01

    The effects of solar ultraviolet (SUV) and ultraviolet type A (UVA) produced by a solar UV simulator on CR-39 detectors were studied. This was done using three techniques: 1 - Alpha tracks diameters and tracks densities, 2 - UV-Vis spectrometry and 3 - FTIR spectrometry. The detectors were divided into two groups, the first was exposed to UV and then to alpha particles, the second group was exposed to alpha particles first and then to UV. The results showed that the effect of UVA on CR-39 was not clear using the three techniques. While, the effect of SUV was clear when using UV-Vis and FTIR spectrometric, and not clear when using track parameters

  16. CR-39 (PADC) Reflection and Transmission of Light in the Ultraviolet-Near-Infrared (UV-NIR) Range.

    Science.gov (United States)

    Traynor, Nathan B J; McLauchlin, Christopher; Dodge, Kenneth; McGarrah, James E; Padalino, Stephen J; McCluskey, Michelle; Sangster, T C; McLean, James G

    2018-04-01

    The spectral reflection (specular and diffuse) and transmission of Columbia Resin 39 (CR-39) were measured for incoherent light with wavelengths in the range of 200-2500 nm. These results will be of use for the optical characterization of CR-39, as well as in investigations of the chemical modifications of the polymer caused by ultraviolet (UV) exposure. A Varian Cary 5000 was used to perform spectroscopy on several different thicknesses of CR-39. With proper analysis for the interdependence of reflectance and transmittance, results are consistent across all samples. The reflectivity from each CR-39-air boundary reveals an increase in the index of refraction in the near-UV. Absorption observations are consistent with the Beer-Lambert law. Strong absorption of UV light of wavelength shorter than 350 nm suggests an optical band gap of 3.5 eV, although the standard analysis is not conclusive. Absorption features observed in the near infrared are assigned to molecular vibrations, including some that are new to the literature.

  17. Electrochemically deposited and etched membranes with precisely sized micropores for biological fluids microfiltration

    International Nuclear Information System (INIS)

    Hamzah, A A; Zainal Abidin, H E; Yeop Majlis, B; Mohd Nor, M; Ismardi, A; Sugandi, G; Tiong, T Y; Dee, C F; Yunas, J

    2013-01-01

    This paper presents simple and economical, yet reliable techniques to fabricate a micro-fluidic filter for MEMS lab-on-chip (LoC) applications. The microporous filter is a crucial component in a MEMS LoC system. Microsized components and contaminants in biological fluids are selectively filtered using copper and silicon membranes with precisely controlled microsized pores. Two techniques were explored in microporous membrane fabrication, namely copper electroplating and electrochemical etching (ECE) of silicon. In the first technique, a copper membrane with evenly distributed micropores was fabricated by electroplating the copper layer on the silicon nitride membrane, which was later removed to leave the freestanding microporous membrane structure. The second approach involves the thinning of bulk silicon down to a few micrometers thick using KOH and etching the resulting silicon membrane in 5% HF by ECE to create micropores. Upon testing with nanoparticles of various sizes, it was observed that electroplated copper membrane passes nanoparticles up to 200 nm wide, while porous silicon membrane passes nanoparticles up to 380 nm in size. Due to process compatibility, simplicity, and low-cost fabrication, electroplated copper and porous silicon membranes enable synchronized microfilter fabrication and integration into the MEMS LoC system. (paper)

  18. Response of CR-39 SSNTD to high energy neutrons using zirconium convertors - a Monte Carlo and experimental study

    International Nuclear Information System (INIS)

    Pal, Rupali; Sapra, B.K.; Bakshi, A.K.; Datta, D.; Biju, K.; Suryanarayana, S.V.; Nayak, B.K.

    2016-01-01

    Neutron dosimetry in ion accelerators is a challenging field as the neutron spectrum varies from thermal, to fast and high-energy neutrons usually extending beyond 20 MeV. Solid-state Nuclear Track Detectors (SSNTDs) have been increasingly used in numerous fields related to nuclear physics. Extensive work has also been carried out on determining the response characteristics of such detectors as nuclear spectrometers. In nuclear reaction studies, identification of reaction products according to their type and energy is frequently required. For normally incident particles, energy-dispersive track-diameter methods have become useful scientific tools using CR-39 SSNTD. CR-39 along with 1 mm polyethylene convertor can cover a neutron energy range from 100 keV to 10 MeV. The neutron interacts with the hydrogen in CR-39 producing recoil protons from elastic collisions. This detectable neutron energy range can be increased by modification in the radiator/convertor used along with CR-39. CR39 detectors placed in conjunction with judiciously chosen thicknesses of a polyethylene radiator and a lead absorber (or degrader) are used to increase energy range upto 19 MeV. A portable neutron counter has been proposed for high-energy neutron measurement with 1 cm thick Zirconium (Zr) as the converter outside a spherical HDPE shell of 7 inch diameter. Zr metal has been found to show (n,2n) cross section for energies above 10 MeV starting from 0.01 barns for 8 MeV upto 1 barns for 22 MeV. Above these energies, the experimental data is scarce. In this paper, Zr was used in conjunction with CR-39 which showed an enhancement of track density on the CR-39. This paper demonstrates the enhancement of neutron response using Zr on CR-39 with both theoretical and experimental studies

  19. Preparation of Chemically Etched Tips for Ambient Instructional Scanning Tunneling Microscopy

    Science.gov (United States)

    Zaccardi, Margot J.; Winkelmann, Kurt; Olson, Joel A.

    2010-01-01

    A first-year laboratory experiment that utilizes concepts of electrochemical tip etching for scanning tunneling microscopy (STM) is described. This experiment can be used in conjunction with any STM experiment. Students electrochemically etch gold STM tips using a time-efficient method, which can then be used in an instructional grade STM that…

  20. CR-39 track detector calibration for H, He, and C ions from 0.1-0.5 MeV up to 5 MeV for laser-induced nuclear fusion product identification.

    Science.gov (United States)

    Baccou, C; Yahia, V; Depierreux, S; Neuville, C; Goyon, C; Consoli, F; De Angelis, R; Ducret, J E; Boutoux, G; Rafelski, J; Labaune, C

    2015-08-01

    Laser-accelerated ion beams can be used in many applications and, especially, to initiate nuclear reactions out of thermal equilibrium. We have experimentally studied aneutronic fusion reactions induced by protons accelerated by the Target Normal Sheath Acceleration mechanism, colliding with a boron target. Such experiments require a rigorous method to identify the reaction products (alpha particles) collected in detectors among a few other ion species such as protons or carbon ions, for example. CR-39 track detectors are widely used because they are mostly sensitive to ions and their efficiency is near 100%. We present a complete calibration of CR-39 track detector for protons, alpha particles, and carbon ions. We give measurements of their track diameters for energy ranging from hundreds of keV to a few MeV and for etching times between 1 and 8 h. We used these results to identify alpha particles in our experiments on proton-boron fusion reactions initiated by laser-accelerated protons. We show that their number clearly increases when the boron fuel is preformed in a plasma state.

  1. Personal Dosemeter of Thermal Neutron Using A Cr-39 Detector with Filter Natural LiF

    International Nuclear Information System (INIS)

    Sofyan, Hasnel; Thamrin, M.Thoyib

    1996-01-01

    The research of personal dosemeter for thermal neutron using Cr-39 detector with different thicknesses of natural LiF filter was carried out. The irradiation of Cr-39 detector with neutron source from reactor research TRIGA mark II of Rikkyo University Tokyo, Japan. Nuclear track was counted by automatic method with ASPECT ver.4.22 Series A4T124 software and manual method for correction. The result of research, the maximum of nuclear tracks was obtained at 8 mm of LiF filter was 10 mm with 11,630x10E-5 track/neutron for air radiation. And on phantom radiation, the thickness of filter was 10 mm with 11,630x10E-5 track/neutron. Its values were 3.6 and 7.5 bigger than the response of Cr-39 non filter in air and on phantom radiation, respectively

  2. Nanostructured plasma etched, magnetron sputtered nanolaminar Cr2AlC MAX phase thin films

    International Nuclear Information System (INIS)

    Grieseler, Rolf; Hähnlein, Bernd; Stubenrauch, Mike; Kups, Thomas; Wilke, Marcus; Hopfeld, Marcus; Pezoldt, Jörg; Schaaf, Peter

    2014-01-01

    The knowledge of the mechanical properties of new materials determines essentially their usability and functionality when used in micro- and nanostructures. MAX phases are new and highly interesting materials due to their unique combination of materials properties. In this article a new method for producing the Cr 2 AlC MAX phase is presented. Thin film elemental multilayer deposition and subsequent rapid thermal annealing forms the MAX phase within seconds. Additionally, free standing microstructures (beams and cantilevers) based on this MAX phase films are prepared by plasma etching. The mechanical properties of these MAX phase microstructures are investigated

  3. On the long standing question of nuclear track etch induction time: Surface-cap model

    International Nuclear Information System (INIS)

    Rana, Mukhtar Ahmed

    2008-01-01

    Using a systematic set of experiments, nuclear track etch induction time measurements in a widely used CR-39 detector were completed for accessible track-forming particles (fission fragments, 5.2 MeV alpha particles and 5.9 MeV antiprotons). Results of the present work are compared with appropriately selected published results. The possibility of the use of etch induction time for charged particle identification is evaluated. Analysis of experimental results along with the use of well-established theoretical concepts yielded a model about delay in the start of chemical etching of nuclear tracks. The suggested model proposes the formation of a surface-cap (top segment) in each nuclear track consisting of chemically modified material with almost same or even higher resistance to chemical etching compared with bulk material of the track detector. Existing track formation models are reviewed very briefly, which provide one of the two bases of the proposed model. The other basis of the model is the general behavior of hot or energised material having a connection with an environment containing a number of species like ordinary air. Another reason for the delay in the start of etching is suggested as the absence of localization of etching atoms/molecules, which is present during etching at depth along the latent track

  4. Characterization of a alpha particle detector CR-39 exposed to a source of radium

    International Nuclear Information System (INIS)

    Maino, Leandro Marcondes

    2009-01-01

    In this project, the main goal is the characterization of a alpha particle detector CR-39 exposed to a source of radio. Three detectors were exposed to a source of radium and then chemically treated for different periods. This way, we could analyze these samples and collect the information needed to verify that at least one of the chemical attack, there has been a separation of the energies alpha particles incident with distinct peaks, thus characterizing the CR-39 as alpha spectrometer in the range 2.5 to 6.3 MeV . (author)

  5. Tuning of structural, light emission and wetting properties of nanostructured copper oxide-porous silicon matrix formed on electrochemically etched copper-coated silicon substrates

    Science.gov (United States)

    Naddaf, M.

    2017-01-01

    Matrices of copper oxide-porous silicon nanostructures have been formed by electrochemical etching of copper-coated silicon surfaces in HF-based solution at different etching times (5-15 min). Micro-Raman, X-ray diffraction and X-ray photoelectron spectroscopy results show that the nature of copper oxide in the matrix changes from single-phase copper (I) oxide (Cu2O) to single-phase copper (II) oxide (CuO) on increasing the etching time. This is accompanied with important variation in the content of carbon, carbon hydrides, carbonyl compounds and silicon oxide in the matrix. The matrix formed at the low etching time (5 min) exhibits a single broad "blue" room-temperature photoluminescence (PL) band. On increasing the etching time, the intensity of this band decreases and a much stronger "red" PL band emerges in the PL spectra. The relative intensity of this band with respect to the "blue" band significantly increases on increasing the etching time. The "blue" and "red" PL bands are attributed to Cu2O and porous silicon of the matrix, respectively. In addition, the water contact angle measurements reveal that the hydrophobicity of the matrix surface can be tuned from hydrophobic to superhydrophobic state by controlling the etching time.

  6. Directional Track Selection Technique in CR39 SSNTD for lowyield reaction experiments

    Science.gov (United States)

    Ingenito, Francesco; Andreoli, Pierluigi; Batani, Dimitri; Bonasera, Aldo; Boutoux, Guillaume; Burgy, Frederic; Cipriani, Mattia; Consoli, Fabrizio; Cristofari, Giuseppe; De Angelis, Riccardo; Di Giorgio, Giorgio; Ducret, Jean Eric; Giulietti, Danilo; Jakubowska, Katarzyna

    2018-01-01

    There is a great interest in the study of p-11B aneutronic nuclear fusion reactions, both for energy production and for determination of fusion cross-sections at low energies. In this context we performed experiments at CELIA in which energetic protons, accelerated by the laser ECLIPSE, were directed toward a solid Boron target. Because of the small cross-sections at these energies the number of expected reactions is low. CR39 Solid-State Nuclear Track Detectors (SSNTD) were used to detect the alpha particles produced. Because of the low expected yield, it is difficult to discriminate the tracks due to true fusion products from those due to natural background in the CR39. To this purpose we developed a methodology of particle recognition according to their direction with respect to the detector normal, able to determine the position of their source. We applied this to the specific experiment geometry, so to select from all the tracks those due to particles coming from the region of interaction between accelerated protons and solid boron target. This technique can be of great help on the analysis of SSNTD in experiments with low yield reactions, but can be also generally applied to any experiment where particles reach the track detector with known directions, and for example to improve the detection limit of particle spectrometers using CR39.

  7. Development and application of the electrochemical etching technique. Annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    1980-08-01

    This annual progress report documents further advances in the development and application of electrochemical etching of polycarbonate foils (ECEPF) for fast, intermediate, and thermal neutron dosimetry as well as alpha particle dosimetry. The fast (> 1.1 MeV) and thermal neutron dosimetry techniques were applied to a thorough investigation of the neutron contamination inherent in and about the primary x-ray beam of several medical therapy electron accelerators. Because of the small size of ECEPF dosimeters in comparison to other neutron meters, they have an unusually low perturbation of the radiation field under measurement. Due to this small size and the increased sensitivity of the ECEPF dosimeter over current techniques of measuring neutrons in a high photon field, the fast neutron contamination in the primary x-ray beam of all the investigated accelerators was measured with precision and found to be greater than that suggested by the other, more common, neutron dosimetry methods.

  8. Development and application of the electrochemical etching technique. Annual progress report

    International Nuclear Information System (INIS)

    1980-08-01

    This annual progress report documents further advances in the development and application of electrochemical etching of polycarbonate foils (ECEPF) for fast, intermediate, and thermal neutron dosimetry as well as alpha particle dosimetry. The fast (> 1.1 MeV) and thermal neutron dosimetry techniques were applied to a thorough investigation of the neutron contamination inherent in and about the primary x-ray beam of several medical therapy electron accelerators. Because of the small size of ECEPF dosimeters in comparison to other neutron meters, they have an unusually low perturbation of the radiation field under measurement. Due to this small size and the increased sensitivity of the ECEPF dosimeter over current techniques of measuring neutrons in a high photon field, the fast neutron contamination in the primary x-ray beam of all the investigated accelerators was measured with precision and found to be greater than that suggested by the other, more common, neutron dosimetry methods

  9. Low-level radon measurements by nuclear track detectors

    International Nuclear Information System (INIS)

    Koksal, E. M.; Goksel, S. A.; Alkan, H.

    1985-01-01

    In the work to be described here we have developed a passive nuclear track dosimeter to measure the integrated value of indoor radon (Rn-222) over a long period of time. Passive radon dosimeter which we have developed in our laboratories makes use of two small pieces of CR-39 plastic (Allyl diglycol carbonate) as detectors for registering tracks of alpha particles emitted by radon. These CR-39 plastic detectors are fixed on the inside bottom of a cup-shaped polystrene enclosure which is closed at the top by a tissue permeable for gases only. CR-39 detectors exposed to radon gas in the indoor air for a period of six months then are removed and chemically etched to make the alpha particle tracks visible under the microscope. The counts of tracks are evaluated to determine the radon concentration in the air in comparison with the number of tracks produced by a known concentration of radon gas. By using the passive dosimeters developed and the chemical etching procedure descriped here, measurements of indoor radon concentrations were carried out in 45 houses in different districts of the city of Istanbul. In this pilot experiment mean radon concentrations between 0.7 and 3.5 pCi/l have been found in these houses. In order to improve the counting of alpha tracks produced on the detectors a prototype electrochemical etching system in addition to chemical etching, is being developed. (author)

  10. Uranium concentration measurements in human blood for some governorates in Iraq using CR-39 track detector

    International Nuclear Information System (INIS)

    Tawfiq, N.F.; Ali, L.T.; Al-Jobouri, H.A.

    2013-01-01

    The sensitive and simple technique of fission track etch has been applied to determine trace concentration of uranium in blood samples for occupational and non-occupational workers, male and female, using CR-39 track detector that is employed for registration of induced fission tracks. The results show that the highest recorded uranium concentration in human blood of workers in the ministry of Science and Technology were 1.90 ppb (male, 36 years old, 12 years' work experience, and living in Basrah governorate) and minimum concentration 0.26 ppb (female, 40 years old, 10 years' work experience, and living in Baghdad), while for non-occupational worker, the maximum uranium concentration was 1.76 ppb (female, 63 years old, and living in Al-Muthana) and minimum concentration was 0.28 ppb (female, 20 years old, and living in Baghdad). It has also been found that the uranium concentration in human blood samples of workers in the ministry of Science and Technology are higher than those of non-occupational workers, and the uranium concentrations for female workers and for non-occupational workers were higher than those for male workers and non-occupational workers. (author)

  11. Silicon-based photonic crystals fabricated using proton beam writing combined with electrochemical etching method.

    Science.gov (United States)

    Dang, Zhiya; Breese, Mark Bh; Recio-Sánchez, Gonzalo; Azimi, Sara; Song, Jiao; Liang, Haidong; Banas, Agnieszka; Torres-Costa, Vicente; Martín-Palma, Raúl José

    2012-07-23

    A method for fabrication of three-dimensional (3D) silicon nanostructures based on selective formation of porous silicon using ion beam irradiation of bulk p-type silicon followed by electrochemical etching is shown. It opens a route towards the fabrication of two-dimensional (2D) and 3D silicon-based photonic crystals with high flexibility and industrial compatibility. In this work, we present the fabrication of 2D photonic lattice and photonic slab structures and propose a process for the fabrication of 3D woodpile photonic crystals based on this approach. Simulated results of photonic band structures for the fabricated 2D photonic crystals show the presence of TE or TM gap in mid-infrared range.

  12. Computer program for the sensitivity calculation of a CR-39 detector in a diffusion chamber for radon measurements

    Energy Technology Data Exchange (ETDEWEB)

    Nikezic, D., E-mail: nikezic@kg.ac.rs; Stajic, J. M. [Faculty of Science, University of Kragujevac, R. Domanovica 12, Kragujevac 34000 (Serbia); Yu, K. N. [Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue (Hong Kong)

    2014-02-15

    Computer software for calculation of the sensitivity of a CR-39 detector closed in a diffusion chamber to radon is described in this work. The software consists of two programs, both written in the standard Fortran 90 programming language. The physical background and a numerical example are given. Presented software is intended for numerous researches in radon measurement community. Previously published computer programs TRACK-TEST.F90 and TRACK-VISION.F90 [D. Nikezic and K. N. Yu, Comput. Phys. Commun. 174, 160 (2006); D. Nikezic and K. N. Yu, Comput. Phys. Commun. 178, 591 (2008)] are used here as subroutines to calculate the track parameters and to determine whether the track is visible or not, based on the incident angle, impact energy, etching conditions, gray level, and visibility criterion. The results obtained by the software, using five different V functions, were compared with the experimental data found in the literature. Application of two functions in this software reproduced experimental data very well, while other three gave lower sensitivity than experiment.

  13. Distance distribution of bystander effects in alpha-particle irradiated cell populations using a CR-39-based culture dish

    International Nuclear Information System (INIS)

    Gaillard, S.; Pusset, D.; Toledo, S.M. de; Azzam, E.I.; Fromm, M.

    2008-01-01

    Propagation of induced biological effects from irradiated to non-irradiated cells is known to occur in cell cultures exposed to low fluences of charged particles. These bystander effects are currently investigated using microbeam or non-microbeam (broad beams) irradiation techniques. Identification of the targeted and non-targeted bystander cells is critical to our understanding of mechanisms underlying such effects. We developed a novel cell culture dish where the base consists of a thin CR-39 sheet grafted on a thin polyethylene terephthalate (PET) foil. The validity of this device in identifying not only irradiated cells, but also the cellular compartment traversed by the particle track is described. We have optimized track etch parameters that do not interfere with measurement of induced biological endpoints under normal incident irradiation. Thus the culture dishes can be used to determine distance distributions for the propagation of induced biological effects from a hit cell to bystander cells. We describe the computer code developed to determine the distance distributions of propagated biological stress responses in normal human fibroblast cells exposed to very low fluences of alpha particles

  14. Ghost microstructure evolution and identification in the coarse grain heat affected zone of 2.25Cr-1Mo-V-Ti steel using tint etching

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyongwoon [Corporate R& D Institute, Doosan Heavy Industries & Construction,Gwigok-dong, Gyeongsangnam-do Seongsan-gu, Changwon-si 642-792 (Korea, Republic of); Lee, Seonghyeong; Na, Hyesung [School of Materials Science and Engineering, Pusan National University, San 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Kang, Chungyun, E-mail: kangcy@pusan.ac.kr [School of Materials Science and Engineering, Pusan National University, San 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea, Republic of)

    2016-11-15

    Microstructural characteristics of the CGHAZ (coarse grained heat affected zone) made of the 2.25Cr-1Mo-V-Ti material for the thermal power plant boiler tube were discussed using the technique of tint etching. To conduct the micro structural characterization, the sample on which CGHAZ was produced by using a high temperature thermal cycle simulator, Gleeble 3500 equipment was used for comparative analyses using the existing Nital etching (ASTM E407-74) and the alkaline etching (ASTM E40785). The latter was used to observe a specific phase. For the microstructure on which the alkaline etching was experimented, the shape of a black strip (Ghost microstructure) in a few microns was observed, which was not observed from the Nital etching. It was found from the phase identifications based EPMA, EBSD and TEM experiments that the image of the black strip in a few microns represented the alpha phase in which C, Cr and Mo became segregated. In addition, it was verified that austenite and M{sub 23}C{sub 6} phase were present around the segregated zone. Based on such results, the mechanism by which the image of the black strip in a few microns was formed at the CGHAZ. In this study, we have investigated the mechanism of the appeared black strip in the CGHAZ. - Highlights: •Ghost microstructure was observed which was not observed from the nital etching. •Ghost microstructure has high concentrations of carbon and molybdenum than matrix. •Schematic illustration proposed of why Ghost microstructure was generated. •Ghost microstructure caused by partial dissolution of M{sub 23}C{sub 6} precipitation.

  15. NiCr (x) Fe2-x O-4 as cathode materials for electrochemical reduction of NO (x)

    DEFF Research Database (Denmark)

    Bræstrup, Frantz Radzik; Kammer Hansen, Kent

    2010-01-01

    Solid solutions of spinel-type oxides with the composition NiCr x Fe2-x O4 (x = 0.0, 0.5, 1.0, 1.5, 2.0) were prepared with the glycine–nitrate combustion synthesis. Four-point DC resistivity measurements show an increase in the conductivity as more Cr is introduced into the structure, whereas...... dilatometer measurements show that the linear thermal expansion decreases with increasing Cr content. The oxides were used as electrode materials in a pseudo-three-electrode setup in the temperature range of 300–600 °C. Cyclic voltammetry and electrochemical impedance spectroscopy were used to characterize...... the electrochemical behavior in 1% NO, 1% NO2, and 10% O2. NiCr2O4 shows high activity in NO and NO2 relative to O2 and can therefore be considered as a possible electrode material. Peaks were detected in the voltammograms recorded on NiCr2O4 in 1% NO. The origin of the peaks seems to be related to the oxidation...

  16. Radon Measurements in Egypt using passive etched track detectors. A Review

    Energy Technology Data Exchange (ETDEWEB)

    Gomaa, M A [National Network of Radiation Physics. Atomic Energy Authority (Egypt); Hussein, A S [Radiation Protection Department, Nuclear Power Plants Authority, (Egypt); El-Arabi, A M [Physics Department, Faculty of Science, South Valley University, Qena, (Egypt)

    2005-04-01

    Radon and its progeny may cause serious radiation harm to human health such as lung cancer and other types. Radon measurements based on alpha particles etched track detectors (LR-115, CR-39) are very attractive for assessment of radon exposure. This is due to their high sensitivity, low cost, easy to handle and retain a permanent record of data. Also these detectors can incorporate the effects of seasonal and diurnal fluctuation of radon activity concentrations due to physical, geological and meteorological factors. The present review is based mainly on the topic of passive etched track detectors for the measurements of radon in Egypt in the recent years. Published papers includes the measurements of radon in dwellings, working places, Cairo Metro stations, ancient Pharaonic places and uranium exploration galleries as well as assessment of radon in drinking water.

  17. Radon Measurements in Egypt using passive etched track detectors. A Review

    International Nuclear Information System (INIS)

    Gomaa, M.A.; Hussein, A.S.; El-Arabi, A.M.

    2005-01-01

    Radon and its progeny may cause serious radiation harm to human health such as lung cancer and other types. Radon measurements based on alpha particles etched track detectors (LR-115, CR-39) are very attractive for assessment of radon exposure. This is due to their high sensitivity, low cost, easy to handle and retain a permanent record of data. Also these detectors can incorporate the effects of seasonal and diurnal fluctuation of radon activity concentrations due to physical, geological and meteorological factors. The present review is based mainly on the topic of passive etched track detectors for the measurements of radon in Egypt in the recent years. Published papers includes the measurements of radon in dwellings, working places, Cairo Metro stations, ancient Pharaonic places and uranium exploration galleries as well as assessment of radon in drinking water

  18. Masking considerations in chemically assisted ion beam etching of GaAs/AlGaAs laser structures

    International Nuclear Information System (INIS)

    Behfar-Rad, A.; Wong, S.S.; Davis, R.J.; Wolf, E.D.; Cornell Univ., Ithaca, NY

    1989-01-01

    The use of photoresist, Cr, and SiO 2 as etch masks for GaAs/AlGaAs structures in chemically assisted ion beam etching is reported. The optimized etch with a photoresist mask results in a high degree of anisotropy and smooth sidewalls. However, the etched surface contains undesirable features. The etch with a Cr mask is also highly anisotropic, and the etched surface is free of features. The drawback with Cr masks is that the sidewalls are rough. Vertical and smooth sidewalls as well as a featureless surface are obtained with a SiO 2 mask. The SiO 2 mask has been employed to etch the facets of monolithic GaAs/AlGaAs-based laser structures

  19. Review of the state of the art in personnel neutron monitoring with solid state detectors

    International Nuclear Information System (INIS)

    Griffith, R.V.

    1987-01-01

    Albedo systems are the mainstay at many facilities and continue to be refined. Advanced electrochemical etching techniques for CR-39 now yield a dose equivalent response that is nearly constant from 0.1 to 4.0 MeV. Recent studies include use of converters to enhance CR-39 response at both low and high energies. Methods have been suggested for use of CR-39, either alone or in conjunction with albedo and other detectors to provide spectral information as a step to more accurate dosimetry. Limitations in the use of CR-39 primarily center on the lack of consistent, high-quality, dosimetry-grade material, significant angular dependence, and poor dose equivalent response at both low and high energies. Work continues on silicon diodes, with some new designs. The most attractive new dosimetry technique is the bubble-damage or superheated drop detector. Metal-on-silicon (MOS) microelectronics present exciting possibilities for the future. 25 refs., 6 figs

  20. Uranium concentration in blood samples of Southern Iraqi leukemia patients using CR-39 track detector

    International Nuclear Information System (INIS)

    Al-Hamzawi, A.A.; Al-Qadisiyah University, Qadisiyah; Jaafar, M.S.; Tawfiq, N.F.

    2014-01-01

    The simple and effective technique of fission track etch has been applied to determine trace concentration of uranium in human blood samples taken from two groups of male and female participants: leukemia patients and healthy subjects group. The blood samples of leukemia patients and healthy subjects were collected from three key southern governorates namely, Basrah, Muthanna and Dhi-Qar. These governorates were the centers of intensive military activities during the 1991 and 2003 Gulf wars, and the discarded weapons are still lying around in these regions. CR-39 track detector was used for registration of induced fission tracks. The results show that the highest recorded uranium concentration in the blood samples of leukemia patients was 4.71 ppb (female, 45 years old, from Basrah) and the minimum concentration was 1.91 ppb (male, 3 years old, from Muthanna). For healthy group, the maximum uranium concentration was 2.15 ppb (female, 55 years old, from Basrah) and the minimum concentration was 0.86 ppb (male, 5 years old, from Dhi-Qar). It has been found that the uranium concentrations in human blood samples of leukemia patients are higher than those of the healthy group. These uranium concentrations in the leukemia patients group were significantly different (P < 0.001) from those in the healthy group. (author)

  1. The effect of silicon crystallographic orientation on the formation of silicon nanoclusters during anodic electrochemical etching

    International Nuclear Information System (INIS)

    Timokhov, D. F.; Timokhov, F. P.

    2009-01-01

    Possible ways for increasing the photoluminescence quantum yield of porous silicon layers have been investigated. The effect of the anodization parameters on the photoluminescence properties for porous silicon layers formed on silicon substrates with different crystallographic orientations was studied. The average diameters for silicon nanoclusters are calculated from the photoluminescence spectra of porous silicon. The influence of the substrate crystallographic orientation on the photoluminescence quantum yield of porous silicon is revealed. A model explaining the effect of the substrate orientation on the photoluminescence properties for the porous silicon layers formed by anode electrochemical etching is proposed.

  2. CR-39 α track detector and its application in observing of the hot particles in environment

    International Nuclear Information System (INIS)

    Zou Benchuan

    1992-01-01

    CR-39 α track detector is a new α remitting radionuclides plastic detector. It is audio-visual, convenient and economic in the detection of α particle track and the distribution of α emitting radionuclides in environmental samples. CR-39 α track detector is used to observe the hot particles in rock and the hot particles coming from the liquid effluents discharged by spent fuel reprocessing plant in UK in marine environment and got good results

  3. Relation between the size of fog droplets and their contact angles with CR39 surfaces

    International Nuclear Information System (INIS)

    Grosu, G; Andrzejewski, L; Veilleux, G; Ross, G G

    2004-01-01

    The formation of fog on CR39 surfaces has been studied. Water droplets form fog coalesce with time, especially during the first 20 s at the beginning of the formation of fog. Consequently, their mean diameter increases. Formation of fog being related to the wettability of the surfaces, the latter has been increased by the implantation of Ar ions into CR39 surfaces under an oxygen partial pressure. A very wetting CR39 surface with advancing (ACA) and receding (RCA) contact angles below 5 deg. has been obtained with an implantation dose of 1.28x10 17 Ar + cm -2 . In this condition, no formation of fog was observed. Characterization using x-ray photoelectron spectroscopy has shown that the molecular structure of CR39 is strongly modified by Ar + implantation, which would be responsible for the increase in wettability. Unfortunately, both ACA and RCA increase with time, which is called ageing, and the formation of fog is again observed. The diameter and concentration of water droplets forming fog have been plotted against the contact angle. These plots show that no formation of fog occurs for ACA 15 He + cm -2 and an energy of 2 keV, sufficient to push the ions deeper than the Ar depth profile, delays the ageing effect in such a way that ACA ≅ 40 deg. is reached after ∼2000 h and no formation of fog is observed during these first ∼2000 h

  4. Effect of post-etch annealing gas composition on the structural and electrochemical properties of Ti2CTx MXene electrodes for supercapacitor applications

    KAUST Repository

    Rakhi, R. B.

    2015-07-08

    Two-dimensional Ti2CTx MXene nanosheets were prepared by the selective etching of Al layer from Ti2AlC MAX phase using HF treatment. The MXene sheets retained the hexagonal symmetry of the parent Ti2AlC MAX phase. Effect of the post-etch annealing ambient (Ar, N2, N2/H2 and Air) on the structure and electrochemical properties of the MXene nanosheets was investigated in detail. After annealing in Air, the MXene sheets exhibited variations in structure, morphology and electrochemical properties as compared to HF treated MAX phase. In contrast, samples annealed in Ar, N2 and N2/H2 ambient retained their original morphology. However, a significant improvement in the supercapacitor performance is observed upon heat treatment in Ar, N2 and N2/H2 ambients. When used in symmetric two-electrode configuration, the MXene sample annealed in N2/H2 atmosphere exhibited the best capacitive performance with specific capacitance value (51 F/g at 1A/g) and high rate performance (86%). This improvement in the electrochemical performance of annealed samples is attributed to highest carbon content, and lowest fluorine content on the surface of the sample upon annealing, while retaining the original 2D layered morphology, and providing maximum access of aqueous electrolyte to the electrodes.

  5. Influence of Reactive Ion Etching on THz Transmission and Reflection Properties of NiCr Film Deposited on a Dielectric Substrate

    Directory of Open Access Journals (Sweden)

    Jun Gou

    2015-06-01

    Full Text Available Enhanced terahertz (THz absorption of NiCr film deposited on a dielectric substrate has been proven by applying a reactive ion etching (RIE treatment to the dielectric film. Nano – scale nickel – chromium (NiCr thin films are deposited on RIE treated silicon dioxide (SiO2 dielectric substrates to study the transmission and reflection characteristics. Experimental results suggest that both transmission and reflection of NiCr film are weakened by the RIE treatment. The most significant decrease of transmission is observed in 1 ~ 4 THz while that of reflection occurs in 1.7 ~ 2.5 THz band. The decrease of both transmission and reflection is more significant for NiCr film with higher thickness. The RIE treatment, which induces nano – scale surface structures and increases the effective surface area of NiCr film, enhances the absorption and weakens the transmission and reflection of THz radiation.DOI: http://dx.doi.org/10.5755/j01.ms.21.2.6131

  6. Angular and dose dependence of CR-39 neutron response for shape-selected tracks

    CERN Document Server

    Tam, N C; Lakosi, L

    1999-01-01

    A shape selection method corresponding to an energy discrimination was used to eliminate unwanted events disturbing evaluation of CR-39 detectors in detecting tracks induced by particles both of perpendicular and oblique incidence. The angular dependence of the response was examined, detecting fast neutrons from sup 2 sup 5 sup 2 Cf with shape selection technique at various angles and distances. Also, the CR-39 track detectors with the sup 2 sup 5 sup 2 Cf source were exposed to high gamma-intensity of a sup 6 sup 0 Co irradiation facility in the range 0.1 to 4.5 kGy, similar to the exposures inside spent fuel assemblies. Using the two functions the lower limit of burnup could be determined by the method.

  7. Characterization of Ag-porous silicon nanostructured layer formed by an electrochemical etching of p-type silicon surface for bio-application

    Science.gov (United States)

    Naddaf, M.; Al-Mariri, A.; Haj-Mhmoud, N.

    2017-06-01

    Nanostructured layers composed of silver-porous silicon (Ag-PS) have been formed by an electrochemical etching of p-type (1 1 1) silicon substrate in a AgNO3:HF:C2H5OH solution at different etching times (10 min-30 min). Scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS) results reveal that the produced layers consist of Ag dendrites and a silicon-rich porous structure. The nanostructuring nature of the layer has been confirmed by spatial micro-Raman scattering and x-ray diffraction techniques. The Ag dendrites exhibit a surface-enhanced Raman scattering (SERS) spectrum, while the porous structure shows a typical PS Raman spectrum. Upon increasing the etching time, the average size of silicon nanocrystallite in the PS network decreases, while the average size of Ag nanocrystals is slightly affected. In addition, the immobilization of prokaryote Salmonella typhimurium DNA via physical adsorption onto the Ag-PS layer has been performed to demonstrate its efficiency as a platform for detection of biological molecules using SERS.

  8. A new parameter in the electrochemical etching of polymer track detectors

    International Nuclear Information System (INIS)

    Sohrabi, M.; Katouzi, M.

    1993-01-01

    It was discovered that the pressure applied to the electrochemical etching (ECE) chamber system and in turn to washers holding the detector tight in place between two semi-chambers has a direct effect on the internal heating and time to breakdown of the polymer detector. The effect was found to be dependent on the type, material, shape and size of the washers holding the detector in place under pressure. To verify such parameters, a pressure ECE chamber (PECE) with measurable and reproducible pressure was designed and constructed. Three types of rubber washers, such as ''O'' rings, flat rings and sheets as well as polycarbonate (PC) detectors glued directly between two semi-syringes, were used. Flat rubber sheets were shown to have relatively minor effects on the internal heating rate and are recommended. The effect seems to be due to forced vibrations of the detector under an electric field, the frequency of which depends on the degree to which the detector is stretched under pressure, like winding the strings of a musical instrument. The results of the above studies are presented and discussed. (orig.)

  9. Design of characteristic parameters for controlling tungsten tip profile during electrochemical etching

    Energy Technology Data Exchange (ETDEWEB)

    Le Duy Cuong; Duong, Thanh Hung; Kim, Huyn Chul [Inje University, Gimhae (Korea, Republic of)

    2014-05-15

    Micro/nano-scale tungsten tips fabricated by electrochemical etching have many diverse industrial applications. The characteristic parameters of the tungsten tip profile include apex radius, taper angle, and aspect ratio. These parameters are governed by many factors including applied voltage, concentration of the electrolyte (potassium hydroxide) solution, and diameter of the inner gold ring. However, a systematic investigation with the aim of determining the best conditions for fabricating micro/nano-scale tips with desired profiles has not been carried out yet. This study is aimed at obtaining controllable tungsten tip -particularly with respect to the radius of curvature and aspect ratio of tips (taper angle)-by altering the experimental conditions. A series of experiments were executed and the results were aggregated and analyzed using response surface methodology in order to identify the relationships between the tungsten tip characteristics and input parameters. The method proposed herein would prove to be suitable for a variety of applications in industries that require tungsten tips with a specific profile.

  10. Design of characteristic parameters for controlling tungsten tip profile during electrochemical etching

    International Nuclear Information System (INIS)

    Le Duy Cuong; Duong, Thanh Hung; Kim, Huyn Chul

    2014-01-01

    Micro/nano-scale tungsten tips fabricated by electrochemical etching have many diverse industrial applications. The characteristic parameters of the tungsten tip profile include apex radius, taper angle, and aspect ratio. These parameters are governed by many factors including applied voltage, concentration of the electrolyte (potassium hydroxide) solution, and diameter of the inner gold ring. However, a systematic investigation with the aim of determining the best conditions for fabricating micro/nano-scale tips with desired profiles has not been carried out yet. This study is aimed at obtaining controllable tungsten tip -particularly with respect to the radius of curvature and aspect ratio of tips (taper angle)-by altering the experimental conditions. A series of experiments were executed and the results were aggregated and analyzed using response surface methodology in order to identify the relationships between the tungsten tip characteristics and input parameters. The method proposed herein would prove to be suitable for a variety of applications in industries that require tungsten tips with a specific profile

  11. Calibration of detectors type CR-39 for methodology implementation for Radon-222 determination in CRCN-NE, Brazil

    International Nuclear Information System (INIS)

    Silva, Karolayne E.M. da; Santos, Mariana L. de O.; Amaral, Déric S. do; Vilela, Eldice C.; França, Elvis J. de; Hazin, Clovis A.; Farias, Emerson E.G. de

    2017-01-01

    Radon-222 is a radioactive gas, a product of the decay of uranium-238, which emits alpha particles and represents more than 50% of the dose of natural radiation received by the population. Therefore, monitoring of this gas is essential. For indoor measurement, solid state detectors can be used, the most common of which is CR-39. For monitoring using CR-39, alpha particles, generated by radon-222 and the daughter radionuclides, strike the surface of the detector and generate traces. To relate the trace density per exposure area in environments with unknown activity concentration, it is necessary to determine the calibration factor. The objective of this study was to calibrate CR-39 type detectors for the implementation of the radon determination methodology in Centro Regional de Ciencias Nucleares do Nordeste - CRCN-NE of Brazilian Nuclear Energy Commission - CNEN. In order to determine the CR-39 calibration factor, 19 exposures of the detectors were performed in the CRCN-NE calibration chamber (RN1-CRCN) at an activity of 5.00 kBq m -3 , with the exposure time varying from 24 to 850 hours. For the detection of the detectors, sodium hydroxide was used in a thermostat bath at 90 ° C for 5 hours. The count of number of traits per unit of field was performed with the aid of optical microscopy with an increase of 100 times, being read 30 fields per dosimeters. As a result, the calibration factor was obtained, and the linear response of the trace density as a function of exposure was observed. The results allow the use of CR-39 in the determination of radon-222 by CRCN-NE

  12. Neutron measurement in 12,13C+ 27Al system using CR-39 detectors and neutron rem meter

    International Nuclear Information System (INIS)

    Sahoo, G.S.; Tripathy, S.P.; Shanbhag, A.A.; Sunil, C.; Joshi, D.S.; Sarkar, P.K.

    2011-01-01

    In this work, neutron measurements carried out for the interaction of 60 and 67.5 MeV 12 C, 57.3 and 65 MeV 13 C ions with thick aluminium target by using CR-39 detectors and neutron rem meter is reported. Both the detector systems were irradiated at different angles viz. 0 deg, 30 deg, 60 deg, 90 deg with respect to the beam direction. The normalized track density measurements (tracks/cm 2 /projectile at 1m) in CR-39 detectors were correlated with the normalized dose equivalent values (μSv/projectile at 1m) obtained using the neutron rem meter. The track density was found to be more in case of 13 C than 12 C. However in all the cases, the track density per incident projectile was found to decrease as the angle with respect to beam direction increases, indicating non-isotropic nature of neutron emission. The ratio between measured dose equivalent in rem meter to the measured track densities in CR-39 detectors was found to be 2.8±0.2, which remains constant irrespective of the change in angle from beam direction as well as neutron spectrum, indicating a flat dose response of CR-39 detectors. (author)

  13. On the X-ray reflectivity by poly allyl diglycol carbonate (PADC)

    International Nuclear Information System (INIS)

    Ghazaly, M. El

    2011-01-01

    X-ray reflectivity via the poly allyl diglycol carbonate (CR-39 polymer sheet) was investigated. X-ray reflectivity was measured for a pristine and a chemically etched CR-39 detector in 6.25N NaOH at (70 ± 0.5) .deg. C for different durations. Far from the spectral peak, the reflectivity of the CR-39 polymer sheet has a wide peak at 2θ = 20.1 .deg. , and its intensity is decreased by increasing the etching time. Moreover, the integrated counts under the peaks, C(t e ), vary linearly as a function of the etching time t e . Data are fitted using a linear function C(t e ) = A+Bt e , with fitting parameters A = (3271 ± 170) and B = (- 960 ± 84). The reflectivity deterioration is attributed to the increase of CR-39 surface's roughness due to the chemical etching. The rocking curves of X-ray reflectivity were measured for a pristine and an etched CR-39 polymer sheet. Specular reflections are observed, as well as Yoneda wings, which broaden and move away from the specular reflections due to the increase in the CR-39 surface's roughness.

  14. Proton radiographic characteristics of thin CR-39 detector

    International Nuclear Information System (INIS)

    Waheed, A.; Manzoor, S.; Khan, H.A.; Urlep, I.; Ilic, R.

    1991-01-01

    Two parameters, track registration sensitivity and densitometric response, were measured in radiography with a low energy (∼4.5 MeV) proton beam and a stack of thin (100μm) CR-39 detector foils. The optimum image quality was obtained at a layer removal thickness of about 1 μm. The image obtained under these conditions is characterized by a high track registration sensitivity (∼60%), high image contrast (the maximum value of the net optical density is ∼0.7) and high spatial resolution (∼1 μm). The application of the technique in biomedicine is illustrated by proton radiographs of botanical samples. (author)

  15. Electrodeposited manganese dioxide nanostructures on electro-etched carbon fibers: High performance materials for supercapacitor applications

    International Nuclear Information System (INIS)

    Kazemi, Sayed Habib; Maghami, Mostafa Ghaem; Kiani, Mohammad Ali

    2014-01-01

    Highlights: • We report a facile method for fabrication of MnO 2 nanostructures on electro-etched carbon fiber. • MnO 2 -ECF electrode shows outstanding supercapacitive behavior even at high discharge rates. • Exceptional cycle stability was achieved for MnO 2 -ECF electrode. • The coulombic efficiency of MnO 2 -ECF electrode is nearly 100%. - Abstract: In this article we introduce a facile, low cost and additive/template free method to fabricate high-rate electrochemical capacitors. Manganese oxide nanostructures were electrodeposited on electro-etched carbon fiber substrate by applying a constant anodic current. Nanostructured MnO 2 on electro-etched carbon fiber was characterized by scanning electron microscopy, X-ray diffraction and energy dispersive X-ray analysis. The electrochemical behavior of MnO 2 electro-etched carbon fiber electrode was investigated by electrochemical techniques including cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. A maximum specific capacitance of 728.5 F g −1 was achieved at a scan rate of 5 mV s −1 for MnO 2 electro-etched carbon fiber electrode. Also, this electrode showed exceptional cycle stability, suggesting that it can be considered as a good candidate for supercapacitor electrodes

  16. Electrodeposited manganese dioxide nanostructures on electro-etched carbon fibers: High performance materials for supercapacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Kazemi, Sayed Habib, E-mail: habibkazemi@iasbs.ac.ir [Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Center for Research in Climate Change and Global Warming (CRCC), Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Maghami, Mostafa Ghaem [Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Kiani, Mohammad Ali [Chemistry and Chemical Engineering Research Center of Iran, P.O. Box 14335-186, Tehran (Iran, Islamic Republic of)

    2014-12-15

    Highlights: • We report a facile method for fabrication of MnO{sub 2} nanostructures on electro-etched carbon fiber. • MnO{sub 2}-ECF electrode shows outstanding supercapacitive behavior even at high discharge rates. • Exceptional cycle stability was achieved for MnO{sub 2}-ECF electrode. • The coulombic efficiency of MnO{sub 2}-ECF electrode is nearly 100%. - Abstract: In this article we introduce a facile, low cost and additive/template free method to fabricate high-rate electrochemical capacitors. Manganese oxide nanostructures were electrodeposited on electro-etched carbon fiber substrate by applying a constant anodic current. Nanostructured MnO{sub 2} on electro-etched carbon fiber was characterized by scanning electron microscopy, X-ray diffraction and energy dispersive X-ray analysis. The electrochemical behavior of MnO{sub 2} electro-etched carbon fiber electrode was investigated by electrochemical techniques including cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. A maximum specific capacitance of 728.5 F g{sup −1} was achieved at a scan rate of 5 mV s{sup −1} for MnO{sub 2} electro-etched carbon fiber electrode. Also, this electrode showed exceptional cycle stability, suggesting that it can be considered as a good candidate for supercapacitor electrodes.

  17. Studying the response of CR-39 to radon in non-polar liquids above water by Monte Carlo simulation and measurement

    International Nuclear Information System (INIS)

    Rezaie, Mohammad Reza; Sohrabi, Mehdi; Negarestani, Ali

    2013-01-01

    The application of CR-39 has been extensive for measurement of radon and progeny in air of dwellings, but limited as regards to measurements of radon in water. In this paper, a new method is introduced for efficient measurement of radon in water by registering alpha particle tracks in a CR-39 detector placed in a non-polar medium such as cyclohexane, hexane and olive oil when each mixed with water, then separated and fixed above water, as a two-phase media. The method introduced here is however different from the widely used liquid - liquid extraction technique by liquid scintillation spectrometry since it is a passive detection method (CR-39) in a non-polar liquid with enhanced absorption of radon in the liquid, it has a capability for long sample counting to decrease the minimum detection limit (MDL), it does not require sophisticated low light counting systems, and it has the potential for simultaneous measurements of large number of samples for large-scale applications. It also has a low cost and is readily available. A new Monte Carlo calculation of energy-distance travelled by alphas from radon and progeny in a medium was also investigated. The sensitivity of CR-39 detector to radon and progeny in water was determined under two conditions; in a single-phase and two-phase media. In a single-phase medium, CR-39 is directly placed either in air, water, cyclohexane, hexane or olive oil. When CR-39 is placed directly in water, its sensitivity is (2.4 ± 0.1) × 10 −4 (track/cm 2 )/(Bq.d/m 3 ). In the two-phase media, CR-39 is placed either in cyclohexane, hexane or olive oil when each is fixed above water. The sensitivities in the two-phase media are significantly enhanced and are respectively (1.98 ± 0.10) × 10 −2 , (2.8 ± 0.15) × 10 −2 and (2.86 ± 0.15) × 10 −2 (track/cm 2 )/(Bq.d/m 3 ). The sensitivies are about 76, 82 and 110 times more than that of when CR-39 is directly placed in water. The new method is a novel alternative for radon

  18. Changes in CR-39 proton sensitivity due to prolonged exposure to high vacuums relevant to the National Ignition Facility and OMEGA.

    Science.gov (United States)

    Manuel, M J-E; Rosenberg, M J; Sinenian, N; Rinderknecht, H; Zylstra, A B; Séguin, F H; Frenje, J; Li, C K; Petrasso, R D

    2011-09-01

    When used at facilities like OMEGA and the NIF, CR-39 is exposed to high vacuum environments before and after irradiation by charged particles and neutrons. Using an electrostatic linear accelerator at MIT, studies have been conducted to investigate the effects of high vacuum exposure on the sensitivity of CR-39 to fusion protons in the ~1-9 MeV energy range. High vacuum conditions, of order 10(-5) Torr, experienced by CR-39 samples at these facilities were emulated. It is shown that vacuum exposure times longer than ~16 h before proton irradiation result in a decrease in proton sensitivity, whereas no effect was observed for up to 67 h of vacuum exposure after proton irradiation. CR-39 sensitivity curves are presented for samples with prolonged exposure to high vacuum before and after proton irradiation. © 2011 American Institute of Physics

  19. Measurement of bulk etch rates for poly-allyl-diglycol carbonate (PADC) and cellulose nitrate in a broad range of concentration and temperature of NaOH etching solution

    International Nuclear Information System (INIS)

    Hermsdorf, D.; Hunger, M.; Starke, S.; Weickert, F.

    2007-01-01

    In the present work the dependence of the bulk etch rate v B for solid state nuclear track detectors (SSNTD) on the concentration c and the temperature T of the NaOH etching solution has been studied for material types PADC and cellulose nitrate. As commonly applied exponents of PADC and cellulose nitrate material, the commercial products CR-39 and LR-115 were investigated. The concentration and temperature have been varied in the ranges 0.5moll -1 -1 and 313 -1 and T between 313 and 333K for cellulose nitrate, respectively. The application of a simple Arrhenius-law of chemical reactions fails in the interpretation of the dependence on the concentration. A constant activation energy cannot describe the behaviour of v B (c,T) over the whole range of concentration. To understand the deviation, more qualified models treating the superposition of chemical and physical processes including reaction kinetics and material transport phenomena by diffusion have to be developed and tested

  20. Effect of the carbon dioxide pressure on the electrochemical behavior of 3Cr low alloyed steel at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Zhijun, E-mail: jiazhijunwin@163.com [Department of Chemical Engineering, University of Tsinghua, Beijing 100084 (China); Key Laboratory of Corrosion and Protection of Chinese Ministry of Education, University of Science and Technology Beijing, Beijing 100083 (China); Li, Xiaogang; Du, Cuiwei; Liu, Zhiyong; Gao, Jin [Key Laboratory of Corrosion and Protection of Chinese Ministry of Education, University of Science and Technology Beijing, Beijing 100083 (China)

    2012-10-15

    Electrochemical corrosion behavior of 3Cr steel in CO{sub 2}-containing solution at a high temperature was investigated by various electrochemical measurements and analysis as well as thermodynamic calculations of ionic concentrations and equilibrium electrode potentials. A conceptual model was developed to illustrate the electrochemical corrosion mechanism of 3Cr steel in the CO{sub 2}-containing sodium chloride solution. Comparing the corrosion potentials of 3Cr steel in the test solution under different CO{sub 2} pressures with the conceptual model, it is found that anodic reactions of the 3Cr steel contain a direct dissolution of Fe, and the formation of corrosion scales, FeCO{sub 3} and Cr(OH){sub 3}, by Fe+HCO{sub 3}{sup -}=FeCO{sub 3}+H{sup +}+2e and Cr + 3OH{sup -} = Cr(OH){sub 3}. With the CO{sub 2} pressure increasing, the corrosion potential has a positive shift. It indicates that the CO{sub 2} pressure has a greater effect on the cathodic reaction than that of anodic reaction. And the corrosion current has positive linear relationship with the increase of CO{sub 2} pressure. It is attributed to the concentration increasing of the reactants of the cathodic reaction. According to analysis of the electrochemical impedance spectroscopy, the scale forming reactions dominate the corrosion process when the CO{sub 2} pressure is lower than 0.6 MPa and the dissolution of Fe, followed by the consecutive mechanism with adsorbed intermediate products, takes up the dominant part in the anodic process when the CO{sub 2} pressure exceeds 0.6 MPa. -- Highlights: Black-Right-Pointing-Pointer A conceptual model is developed to illustrate the corrosion mechanism. Black-Right-Pointing-Pointer A good reference electrode which is used at high temperature is made. Black-Right-Pointing-Pointer Corrosion current has positive linear relationship with the increase of CO{sub 2} pressure. Black-Right-Pointing-Pointer CO{sub 2} pressure has a greater effect on cathodic reaction than

  1. Modifications in the optical and thermal properties of a CR-39 polymeric detector induced by high doses of γ-radiation

    Science.gov (United States)

    Saad, A. F.; Ibraheim, Mona H.; Nwara, Aya M.; Kandil, S. A.

    2018-04-01

    Effects of γ-radiation on the optical and thermal properties of a poly allyl diglycol carbonate (PADC), a form of CR-39, polymer have been investigated. CR-39 detectors were exposed to γ-rays at very high doses ranging from 5.0 × 105 to 3.0 × 106 Gy. The induced changes were analyzed using ultraviolet-visible spectroscopy (UV-VIS) in absorbance mode, and thermogravimetric analysis (TGA). The UV-visible spectra of the virgin and γ-irradiated CR-39 polymer detectors displayed a significant decreasing trend in their optical energy band gaps for indirect transitions, whereas for the direct ones showed a little change. This drop in the energy band gap with increasing dose is discussed on the basis of the gamma irradiation induced modifications in the CR-39 polymeric detector. The TGA thermograms show that the weight loss rate increased with increase in dose, which may be due to the disordered system via scission followed by crosslinking in the irradiated polymer detector. The TGA thermograms also indicated that the CR-39 detector decomposed in three/four stages for the virgin and irradiated samples. The activation energy for thermal decomposition was determined using a type of Arrhenius equation based on the TGA experimental results. These experimental results so obtained can be well used in radiation dosimetry.

  2. Studies on neutron detection with solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Khouri, M.C.; Vilela, E.C.; Andrade, C. de.

    1993-03-01

    The detection of thermal and fast neutrons was studied. For thermal neutrons, alpha sensitive plastic was used in order to register the products of nuclear reactions taking place in boron and /or lithium converters. Fast neutrons produce recoil tracks within the detector. In the present case, CR-39 and Makrofol E were used. Chemical and electrochemical etching processes were used for thermal and fast neutron detectors, respectively. (F.E.). 6 refs, 4 figs, 6 tabs

  3. Development of hybrid track detector using CR39 and photographic plate

    International Nuclear Information System (INIS)

    Kuge, K.; Endo, Y.; Hayashi, K.; Iwakiri, S.; Hasegawa, A.; Yasuda, N.; Kumagai, H.

    2005-01-01

    To improve the hybrid track detector using both CR39 and silver halide photography the gold deposition development technique was applied to this. Nuclear tracks composed of gold clusters were obtained. This method has several advantages; 1. no filament formation, 2. easy control of the cluster size owing to the independence of the size of silver halide grain, 3. easy treatment of the waste solution of developer. (author)

  4. Electrochemical regeneration of chrome etching solution

    NARCIS (Netherlands)

    Andel, van Y.; Janssen, L.J.J.

    2002-01-01

    A metal surface is chromatized with a chromic acid solution to obtain a good adherence of polymer coatings. In this process Cr(VI) is reduced to Cr(III). The oxidation strength of the solution decreases during use. The chrome solution needs to be regenerated and purified. A new anode material,

  5. Measurements of radon in dwellings with CR-39 track detectors

    DEFF Research Database (Denmark)

    Majborn, Benny

    1986-01-01

    A passive integrating dosemeter has been designed for measuring natural radiation in dwellings. The dosemeter contains one or two CR-39 track detectors to measure radon and three thermoluminescence dosemeters to measure external radiation. The dosemeter was investigated in a pilot study in 1983....../84, and it is now used in a nationwide survey of natural radiation in Danish dwellings. The characteristics of the dosemeter with respect to radon measurements are presented, and the radon monitoring results obtained in the pilot study are summarized...

  6. Optical and electrical properties of porous silicon layer formed on the textured surface by electrochemical etching

    Science.gov (United States)

    Weiying, Ou; Lei, Zhao; Hongwei, Diao; Jun, Zhang; Wenjing, Wang

    2011-05-01

    Porous silicon (PS) layers were formed on textured crystalline silicon by electrochemical etching in HF-based electrolyte. Optical and electrical properties of the TMAH textured surfaces with PS formation are studied. Moreover, the influences of the initial structures and the anodizing time on the optical and electrical properties of the surfaces after PS formation are investigated. The results show that the TMAH textured surfaces with PS formation present a dramatic decrease in reflectance. The longer the anodizing time is, the lower the reflectance. Moreover, an initial surface with bigger pyramids achieved lower reflectance in a short wavelength range. A minimum reflectance of 3.86% at 460 nm is achieved for a short anodizing time of 2 min. Furthermore, the reflectance spectrum of the sample, which was etched in 3 vol.% TMAH for 25 min and then anodized for 20 min, is extremely flat and lies between 3.67% and 6.15% in the wavelength range from 400 to 1040 nm. In addition, for a short anodizing time, a slight increase in the effective carrier lifetime is observed. Our results indicate that PS layers formed on a TMAH textured surface for a short anodization treatment can be used as both broadband antireflection coatings and passivation layers for the application in solar cells.

  7. Optical and electrical properties of porous silicon layer formed on the textured surface by electrochemical etching

    Energy Technology Data Exchange (ETDEWEB)

    Ou Weiying; Zhao Lei; Diao Hongwei; Zhang Jun; Wang Wenjing, E-mail: wjwangwj@126.com [Key Laboratory of Solar Thermal Energy and Photovoltaic System, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China)

    2011-05-15

    Porous silicon (PS) layers were formed on textured crystalline silicon by electrochemical etching in HF-based electrolyte. Optical and electrical properties of the TMAH textured surfaces with PS formation are studied. Moreover, the influences of the initial structures and the anodizing time on the optical and electrical properties of the surfaces after PS formation are investigated. The results show that the TMAH textured surfaces with PS formation present a dramatic decrease in reflectance. The longer the anodizing time is, the lower the reflectance. Moreover, an initial surface with bigger pyramids achieved lower reflectance in a short wavelength range. A minimum reflectance of 3.86% at 460 nm is achieved for a short anodizing time of 2 min. Furthermore, the reflectance spectrum of the sample, which was etched in 3 vol.% TMAH for 25 min and then anodized for 20 min, is extremely flat and lies between 3.67% and 6.15% in the wavelength range from 400 to 1040 nm. In addition, for a short anodizing time, a slight increase in the effective carrier lifetime is observed. Our results indicate that PS layers formed on a TMAH textured surface for a short anodization treatment can be used as both broadband antireflection coatings and passivation layers for the application in solar cells. (semiconductor technology)

  8. Performance enhancement of membrane electrode assemblies with plasma etched polymer electrolyte membrane in PEM fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yong-Hun; Yoon, Won-Sub [School of Advanced Materials Engineering, Kookmin University, 861-1 Jeongneung-dong, Seongbuk-gu, Seoul 136-702 (Korea); Bae, Jin Woo; Cho, Yoon-Hwan; Lim, Ju Wan; Ahn, Minjeh; Jho, Jae Young; Sung, Yung-Eun [World Class University (WCU) program of Chemical Convergence for Energy and Environment (C2E2), School of Chemical and Biological Engineering, College of Engineering, Seoul National University (SNU), 599 Gwanak-Ro, Gwanak-gu, Seoul 151-744 (Korea); Kwon, Nak-Hyun [Fuel Cell Vehicle Team 3, Advanced Technology Center, Corporate Research and Development Division, Hyundai-Kia Motors, 104 Mabuk-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-912 (Korea)

    2010-10-15

    In this work, a surface modified Nafion 212 membrane was fabricated by plasma etching in order to enhance the performance of a membrane electrode assembly (MEA) in a polymer electrolyte membrane fuel cell. Single-cell performance of MEA at 0.7 V was increased by about 19% with membrane that was etched for 10 min compared to that with untreated Nafion 212 membrane. The MEA with membrane etched for 20 min exhibited a current density of 1700 mA cm{sup -2} at 0.35 V, which was 8% higher than that of MEA with untreated membrane (1580 mA cm{sup -2}). The performances of MEAs containing etched membranes were affected by complex factors such as the thickness and surface morphology of the membrane related to etching time. The structural changes and electrochemical properties of the MEAs with etched membranes were characterized by field emission scanning electron microscopy, Fourier transform-infrared spectrometry, electrochemical impedance spectroscopy, and cyclic voltammetry. (author)

  9. Preparation of Track Etch Membrane Filters Using Polystyrene Film

    International Nuclear Information System (INIS)

    Kaewsaenee, Jerawut; Ratanatongchai, Wichian; Supaphol, Pitt; Visal-athaphand, Pinpan

    2007-08-01

    Full text: Polystyrene nuclear track etch membrane filters was prepared by exposed 13 .m thin film polystyrene with fission fragment. Nuclear latent track was enlarged to through hole on the film by etching with 80 o C 40% H 2 SO 4 with K 2 Cr 2 O 7 solution for 6-10 hour. The hole size was depend on concentration of etching solution and etching time with 1.3-3.4 .m hole diameter. The flow rate test of water was 0.79-1.56 mm cm-2 min-1 at 109.8-113.7 kPa pressure

  10. Effect of oxygen pressure on sensitivity of CR-39 used for astronauts radiation dosimetry

    International Nuclear Information System (INIS)

    Murai, T.; Yabe, S.; Nagamatsu, A.; Tawara, H.; Kumagai, H.; Miyazawa, Y.; Kitajo, K.; Kodaira, S.; Yasuda, N.

    2006-01-01

    The personal radiation dosimeters for astronauts are exposed to low-pressure oxygen gas (0.29 atmospheres) during extra-vehicle activities. CR-39 plastic track detectors are one of the typical passive dosimeters for space radiation monitoring. We investigated change in track formation sensitivity of the antioxidant-doped CR-39 plastic with which oxygen gas comes in contact at different pressures up to 2 atmospheres for 1h to 10 days. The oxygen effect on sensitivity was measured for the C, Si and Fe ions (10-200 keV/μm) from the HIMAC heavy ion accelerator. The sensitivity is obviously sensitive to oxygen pressure at heavy-ion exposures, but not sensitive to the experience of oxygen atmosphere before and after the ion exposures. The maximum sensitivity is obtained at 0.29 atmospheres. The present experimental data suggested that the effect depends on LET of incident particles. (author)

  11. Dry etching technologies for the advanced binary film

    Science.gov (United States)

    Iino, Yoshinori; Karyu, Makoto; Ita, Hirotsugu; Yoshimori, Tomoaki; Azumano, Hidehito; Muto, Makoto; Nonaka, Mikio

    2011-11-01

    ABF (Advanced Binary Film) developed by Hoya as a photomask for 32 (nm) and larger specifications provides excellent resistance to both mask cleaning and 193 (nm) excimer laser and thereby helps extend the lifetime of the mask itself compared to conventional photomasks and consequently reduces the semiconductor manufacturing cost [1,2,3]. Because ABF uses Ta-based films, which are different from Cr film or MoSi films commonly used for photomask, a new process is required for its etching technology. A patterning technology for ABF was established to perform the dry etching process for Ta-based films by using the knowledge gained from absorption layer etching for EUV mask that required the same Ta-film etching process [4]. Using the mask etching system ARES, which is manufactured by Shibaura Mechatronics, and its optimized etching process, a favorable CD (Critical Dimension) uniformity, a CD linearity and other etching characteristics were obtained in ABF patterning. Those results are reported here.

  12. Environmental dosimetry of radon-222 and daughters: measurement of absolute calibration factors of CR-39 considering the plate-out effects and environmental factors; Dosimetria ambiental de Rn-222 e filhos: medida da eficiencia absoluta do CR-39 levando-se em conta os efeitos do plate-out e fatores ambientais

    Energy Technology Data Exchange (ETDEWEB)

    Paulo, S.R. de

    1991-08-01

    The subject of this work concerns with the measurement of absolute calibration factors for the use of CR-39 as an absolute detector in indoor and daughters monitoring. Up to now the usefulness of calibration factors was restricted to environmental conditions equal (or very close) to those worthing during their determinations. This fact is consequence of the difficulties related to the understanding of the plate-out properties of radon daughters activity in the air. The plate-out effects on radon daughters monitoring performed by SSNTDs are studied. Our experimental results are in agreement with those of other authors about the great sensitivity of CR-39 to the plate-out effects, fact that recommended its use in this work. Being succeeded in the employment of CR-39 as an alpha-spectrometer we concluded that some important information (like the radon daughters deposition rates on the walls of an environment) can be achieved. The knowledge about the behavior of plate-out made possible the determination of the ranges in zenithal angle and energy where CR-39 can detect alpha-particles with efficiency of 100%, at our conditions of track observation. In this way, we obtained calibration factors for CR-39 that are weakly dependent on environmental conditions. We think that these results can contribute to the improvement of RD (Radiation Detector) detection techniques. (author). 159 refs, 106 figs, 05 tabs.

  13. Refined tip preparation by electrochemical etching and ultrahigh vacuum treatment to obtain atomically sharp tips for scanning tunneling microscope and atomic force microscope

    International Nuclear Information System (INIS)

    Hagedorn, Till; Ouali, Mehdi El; Paul, William; Oliver, David; Miyahara, Yoichi; Gruetter, Peter

    2011-01-01

    A modification of the common electrochemical etching setup is presented. The described method reproducibly yields sharp tungsten tips for usage in the scanning tunneling microscope and tuning fork atomic force microscope. In situ treatment under ultrahigh vacuum (p ≤10 -10 mbar) conditions for cleaning and fine sharpening with minimal blunting is described. The structure of the microscopic apex of these tips is atomically resolved with field ion microscopy and cross checked with field emission.

  14. Study of the optical properties and the carbonaceous clusters in thermally-annealed CR-39 and Makrofol-E polymer-based solid-state nuclear track detectors

    International Nuclear Information System (INIS)

    El Ghazaly, M.

    2012-01-01

    The induced modifications in the optical properties of CR-39 and Makrofol-E polymer-based solid state nuclear track detectors were investigated after thermal annealing at a temperature of 200 .deg. C for different durations. The optical properties were studied using an UV-visible spectrophotometer. From the UV-visible spectra, the direct and the indirect optical band gaps, Urbach's energies, and the number of carbon atoms in a cluster were determined. The absorbance of CR-39 plastic detector was found to decrease with increasing annealing time while the absorbance of Makrofol-E decreased with increasing annealing time. The width of the tail of localized states in the band gap ΔE was evaluated with the Urbach method. The optical energy band gaps were obtained from the direct and the indirect allowed transitions in K-space. Both of the direct and the indirect band gaps of the annealed CR-39 detector decrease with increasing annealing time while in Makrofol-E, they decreased after an annealing time of 15 minute and then showed no remarkable changes for a prolonged annealing times. Urbach's energy decreased significantly for both CR-39 and Makrofol-E with increasing annealing time. The number of carbon atoms in a cluster increased in the CR-39 detector with increasing annealing time while it decreased with increasing annealing time for Makrofol-E. We may conclude that the CR-39 detector undergoes greater modifications than the Makrofol-E detector upon thermal annealing at 200 .deg. C. In conclusion, the induced modifications in the optical properties of CR-39 and Makrofol-E are correlated with the temperature and the duration of annealing.

  15. New development on electrochemical etching processes at the Atomic Energy Organization of Iran

    CERN Document Server

    Sohrabi, M

    1999-01-01

    Some highlights of new developments made in our laboratory at the Atomic Energy Organization of Iran on chemical and electrochemical etching (ECE) of polymer track detectors like polycarbonate (PC) are presented. They include introduction of new ECE chamber systems and methods for production of ECE signs and symbols, and a new versatile ECE chamber (VECE) system for multi-purpose, multi-size, and/or multi-shape detector processing; determination of photoneutron doses in and around high-energy X-ray beams of a 20 MV medical accelerator; verification of the Smythe and Mason equations for ECE of tracks in polymers; ECE of alpha and recoil tracks in PC using PMW, PEW and PEMW etchants; introduction of a novel method using ethylene diamine for treatment of PC detectors with its applications, for example in precision removal of surface layers of PC (e.g. bulk removal rates of about 0.04, 0.15, 0.36, 0.66, and 1.33 mm min sup - sup 1 for 60%, 65%, 70%, 75% and 80% ethylene diamine solution (v/v) in water respectivel...

  16. Influence of Oxidation Treatments and Surface Finishing on the Electrochemical Behavior of Ni-20Cr HVOF Coatings

    Science.gov (United States)

    Ruiz-Luna, H.; Porcayo-Calderon, J.; Alvarado-Orozco, J. M.; Mora-García, A. G.; Martinez-Gomez, L.; Trápaga-Martínez, L. G.; Muñoz-Saldaña, J.

    2017-12-01

    The low-temperature electrochemical behavior of HVOF Ni-20Cr coatings was assessed. The coatings were evaluated in different conditions including as-sprayed, as-ground, and heat-treated in air and argon atmospheres. A detailed analysis of the coatings was carried out by means of XRD, SEM, and EPMA, prior and after the corrosion test. The corrosion rate was analyzed in a NaCl solution saturated with CO2. Results demonstrate that the use of a low-oxygen partial pressure favors the formation of a Cr2O3 layer on the surface of the coatings. According to the electrochemical results, the lower corrosion rates were obtained for the heat-treated coatings irrespective of the surface finishing, being the ground and argon heat-treated condition that shows the best corrosion performance. This behavior is due to the synergistic effect of the low-pressure heat treatment and the grinding processes. The grinding promotes a more homogeneous reaction area without surface heterogeneities such as voids, and the pre-oxidation treatment decreases the porosity content of the coating and also allows the growing of a Cr-rich oxide scale which acts as a barrier against the ions of the aqueous solution.

  17. Observations of the effect of varying Hoop stress on fatigue failure and the formation of white etching areas in hydrogen infused 100Cr6 steel rings

    DEFF Research Database (Denmark)

    Janakiraman, Shravan; West, Ole; Klit, Peder

    2015-01-01

    White etching cracks (WECs) in wind turbine gearbox bearings have been studied previously. Rolling contact fatigue (RCF) tests are conducted on 100Cr6 bearing steel rings, in this study, to generate WECs like those found in wind turbine bearings. This research studies the effect of two different...

  18. Reactive ion etching of microphotonic structures

    International Nuclear Information System (INIS)

    Du, J.; Glasscock, J.; Vanajek, J.; Savvides, N.

    2004-01-01

    Full text: Fabrication of microphotonic structures such as planar waveguides and other periodic structures based on silicon technology has become increasingly important due to the potential for integration of planar optical devices. We have fabricated various periodic microstructures on silicon wafers using standard optical lithography and reactive ion etching (RIE). For optical applications the surface roughness and the sidewall angle or steepness of microstructures are the most critical factors. In particular, sidewall roughness of the etched waveguide core accounts for most of the optical propagation loss. We show that by varying the main RIE parameters such as gas pressure, RF power and CF 4 /Ar/O 2 gas composition it is possible to produce microstructures with near-vertical sidewalls and very smooth surfaces. In addition to plasma etching conditions, poor edge quality of the mask often causes sidewall roughness. We employed Ni/Cr metal masks in these experiments for deep etching, and used Ar + ion milling instead of wet chemical etching to open the mask. This improves the edge quality of the mask and ultimately results in smooth sidewalls

  19. Annealing effects on the charged particles registration characteristic of the CR-39 traces solid detector

    International Nuclear Information System (INIS)

    Correa, M.M.

    1989-10-01

    CR-39 trace solid detectors samples, previously exposed to alpha particles and fission fragments from a Cf-252 source, were submitted to a annealing treatment to study his effects on the characteristics of charged particle traces registration. (L.C.J.A.)

  20. Investigation of the Effect of He-Ne Laser on the Optical Properties through Etched CN-85 and CR-39 Containing Alpha Tracks

    International Nuclear Information System (INIS)

    Zaki, M.F.; Hegazy, T.M.; Taha, D.H.

    2013-01-01

    The effects of He-Ne laser on the optical characteristics of Cellulose nitrate, CN-85, and Poly allyl diglycole carbonate, CR-39, nuclear track detectors have been studied by using photoluminescence (PL) and UV-visible spectroscopic techniques. The polymers irradiated with alpha particles with close contact to 241 Am and then exposed to He-Ne laser with different doses. The laser energy intensities ranged between 0 and 217 J/cm 2 . The change in the PL spectra may be explained by chain conformational disorders as well as chain scission. From the UV-visible spectra, it is found that a shift in the absorption edge towards a longer wavelength with increasing laser doses can be readily observed. The absorption peak with increasing dose is seen to change into a broad one. The optical band gaps determined from the UV-visible spectra were found to decrease with the increase of energy intensities of He-Ne laser. These results have been explained on the basis of scission of the polymers due to laser irradiation. The UV absorption tail formation in both polymers was related to the diminution of optical band gap. Results show good correlation with the applied doses.

  1. Track treeing mechanism and plastic zone in solid Part 1: Initial development of plastic zone

    International Nuclear Information System (INIS)

    Li Boyang

    2008-01-01

    After neutron exposure and chemical etching in advance, latent tracks of recoil nucleon develop into pits on CR39 surface. During electrochemical etching, plastic zone is formed at top of pits. Some pits develop into tree cracks in the initial stage of plastic zone development. Physical and mathematical model of crack and plastic zone is proposed; parameter of development free path of plastic zone is presented. Based on integration of elementary theories the stress analysis is build up; based on analyses of measured parameters, a set of common relations between parameters is obtained. Integrate parameter analysis and stress analysis, depth of plastic zone development, law and phenomenon in experimental data can be interpreted completely

  2. Calibration of detectors type CR-39 for methodology implementation for Radon-222 determination in CRCN-NE, Brazil; Calibração de detectores do tipo CR-39 para implementação da metodologia de determinação de radônio-222 no CRCN-NE

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Karolayne E.M. da; Santos, Mariana L. de O.; Amaral, Déric S. do; Vilela, Eldice C.; França, Elvis J. de; Hazin, Clovis A.; Farias, Emerson E.G. de, E-mail: keesthefany@gmail.com, E-mail: marianasantos_ufpe@hotmail.com, E-mail: dericsoares@gmail.com, E-mail: ecvilela@cnen.gov.br, E-mail: ejfrana@cnen.gov.br, E-mail: chazin@cnen.gov.br, E-mail: emersonemiliamo@yahoo.com.br [Centro Regional de Ciências Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2017-07-01

    Radon-222 is a radioactive gas, a product of the decay of uranium-238, which emits alpha particles and represents more than 50% of the dose of natural radiation received by the population. Therefore, monitoring of this gas is essential. For indoor measurement, solid state detectors can be used, the most common of which is CR-39. For monitoring using CR-39, alpha particles, generated by radon-222 and the daughter radionuclides, strike the surface of the detector and generate traces. To relate the trace density per exposure area in environments with unknown activity concentration, it is necessary to determine the calibration factor. The objective of this study was to calibrate CR-39 type detectors for the implementation of the radon determination methodology in Centro Regional de Ciencias Nucleares do Nordeste - CRCN-NE of Brazilian Nuclear Energy Commission - CNEN. In order to determine the CR-39 calibration factor, 19 exposures of the detectors were performed in the CRCN-NE calibration chamber (RN1-CRCN) at an activity of 5.00 kBq m{sup -3}, with the exposure time varying from 24 to 850 hours. For the detection of the detectors, sodium hydroxide was used in a thermostat bath at 90 ° C for 5 hours. The count of number of traits per unit of field was performed with the aid of optical microscopy with an increase of 100 times, being read 30 fields per dosimeters. As a result, the calibration factor was obtained, and the linear response of the trace density as a function of exposure was observed. The results allow the use of CR-39 in the determination of radon-222 by CRCN-NE.

  3. Determination of exhalation rate of radon from walls and indoor radon by CR-39 detectors

    International Nuclear Information System (INIS)

    Vasidov, A.; Tillaev, T.S.

    2007-01-01

    Full text: The knowledge of true value exhalation rate of radon gas from building materials represents scientific and practical interest in environmental radiation protection. This point of view in the paper exhalation rate of radon gas from building materials and a surface of walls with different constructions were determined by detectors CR-39. The values of the exhalation rate of radon per unit area of the granite, concrete, fired and unfired bricks, sand, cement, alabaster varied 0.091 - 0.1 Bq·m -2 ·h -1 . The surface of walls of dwellings constructed from different building materials the exhalation rate of radon are within in limits of 0.083-1.12 Bq·m -2 ·h -1 . Were measurements with CR-39 detectors a level of radon within 50-520 Bq/m 3 in air of rooms constructed of the different building materials

  4. Environmental dosimetry of radon-222 and daughters: measurement of absolute calibration factors of CR-39 considering the plate-out effects and environmental factors

    International Nuclear Information System (INIS)

    Paulo, S.R. de.

    1991-08-01

    The subject of this work concerns with the measurement of absolute calibration factors for the use of CR-39 as an absolute detector in indoor and daughters monitoring. Up to now the usefulness of calibration factors was restricted to environmental conditions equal (or very close) to those worthing during their determinations. This fact is consequence of the difficulties related to the understanding of the plate-out properties of radon daughters activity in the air. The plate-out effects on radon daughters monitoring performed by SSNTDs are studied. Our experimental results are in agreement with those of other authors about the great sensitivity of CR-39 to the plate-out effects, fact that recommended its use in this work. Being succeeded in the employment of CR-39 as an alpha-spectrometer we concluded that some important information (like the radon daughters deposition rates on the walls of an environment) can be achieved. The knowledge about the behavior of plate-out made possible the determination of the ranges in zenithal angle and energy where CR-39 can detect alpha-particles with efficiency of 100%, at our conditions of track observation. In this way, we obtained calibration factors for CR-39 that are weakly dependent on environmental conditions. We think that these results can contribute to the improvement of RD (Radiation Detector) detection techniques. (author). 159 refs, 106 figs, 05 tabs

  5. Atomic scale characterization of white etching area and its adjacent matrix in a martensitic 100Cr6 bearing steel

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.J., E-mail: y.li@mpie.de [Max-Planck Institut für Eisenforschung, Max-Planck-Str. 1, Düsseldorf D-40237 (Germany); Center for Interface-Dominated High Performance Materials, Ruhr-Universität Bochum, Bochum 44780 (Germany); Herbig, M.; Goto, S. [Max-Planck Institut für Eisenforschung, Max-Planck-Str. 1, Düsseldorf D-40237 (Germany); Raabe, D., E-mail: d.raabe@mpie.de [Max-Planck Institut für Eisenforschung, Max-Planck-Str. 1, Düsseldorf D-40237 (Germany)

    2017-01-15

    Atom probe tomography was employed to characterize the microstructure and C distribution in the white etching area (WEA) of a martensitic 100Cr6 bearing steel subjected to rolling contact fatigue. Different from its surrounding matrix where a plate-like martensitic structure prevails, the WEA exhibits equiaxed grains with a uniform grain size of about 10 nm. Significant C grain boundary enrichment (>7.5at.%) and an overall higher C concentration than the nominal value are observed in the WEA. These results suggest that the formation of WEA results from severe local plastic deformation that causes dissolution of carbides and the redistribution of C. - Highlights: •APT has been applied to characterize the microstructure of white etching area (WEA). •Quantitative analyses of C distribution indicate that carbides are dissolved on the WEA. •WEA contains equiaxed grains with a uniform grain size of 10 nm. •C segregation at grain boundaries stabilizes the nanosized grain structure. •Formation of WEA is explained by severe local plastic deformation introduced by cyclic contact loading.

  6. Refined tip preparation by electrochemical etching and ultrahigh vacuum treatment to obtain atomically sharp tips for scanning tunneling microscope and atomic force microscope.

    Science.gov (United States)

    Hagedorn, Till; El Ouali, Mehdi; Paul, William; Oliver, David; Miyahara, Yoichi; Grütter, Peter

    2011-11-01

    A modification of the common electrochemical etching setup is presented. The described method reproducibly yields sharp tungsten tips for usage in the scanning tunneling microscope and tuning fork atomic force microscope. In situ treatment under ultrahigh vacuum (p ≤10(-10) mbar) conditions for cleaning and fine sharpening with minimal blunting is described. The structure of the microscopic apex of these tips is atomically resolved with field ion microscopy and cross checked with field emission. © 2011 American Institute of Physics

  7. Patterning of light-extraction nanostructures on sapphire substrates using nanoimprint and ICP etching with different masking materials.

    Science.gov (United States)

    Chen, Hao; Zhang, Qi; Chou, Stephen Y

    2015-02-27

    Sapphire nanopatterning is the key solution to GaN light emitting diode (LED) light extraction. One challenge is to etch deep nanostructures with a vertical sidewall in sapphire. Here, we report a study of the effects of two masking materials (SiO2 and Cr) and different etching recipes (the reaction gas ratio, the reaction pressure and the inductive power) in a chlorine-based (BCl3 and Cl2) inductively coupled plasma (ICP) etching of deep nanopillars in sapphire, and the etching process optimization. The masking materials were patterned by nanoimprinting. We have achieved high aspect ratio sapphire nanopillar arrays with a much steeper sidewall than the previous etching methods. We discover that the SiO2 mask has much slower erosion rate than the Cr mask under the same etching condition, leading to the deep cylinder-shaped nanopillars (122 nm diameter, 200 nm pitch, 170 nm high, flat top, and a vertical sidewall of 80° angle), rather than the pyramid-shaped shallow pillars (200 nm based diameter, 52 nm height, and 42° sidewall) resulted by using Cr mask. The processes developed are scalable to large volume LED manufacturing.

  8. Electrochemical characterisation of X10CrNi 18-8 steel in artificial plasma

    Directory of Open Access Journals (Sweden)

    J. Przondziono

    2015-01-01

    Full Text Available Quality of applied guide wires conditions the course of treatment and its success to a great extent. In order to simulate conditions that can be found in blood vascular system samples were exposed to artificial blood plasma (T = 37 } 1 oC for the time of 8 h. In order to obtain information regarding physical and chemical properties of modified surface of wire made of X10CrNi 18-8 steel, electrochemical impedance spectroscopy (EIS test and tests of chemical composition of the surface layer X-ray photoelectron spectroscopy (XPS were made. On the ground of performed EIS and XPS tests, favourable impact of steam sterilisation process on corrosion resistance of X10CrNi 18-8 steel was observed only for the case when chemical passivation was applied prior to sterilisation.

  9. Effect of argon ion implantation on the electrical and dielectric properties of CR-39

    International Nuclear Information System (INIS)

    Chawla, Mahak; Shekhawat, Nidhi; Goyal, Meetika; Gupta, Divya; Sharma, Annu; Aggarwal, Sanjeev

    2016-01-01

    The objective of the present work is to study the effect of 130 keV Ar"+ ions on the electrical and dielectric properties of CR-39 samples at various doses 5×10"1"4, 1×10"1"5 and 1×10"1"6 Ar"+ cm"−"2. Current-Voltage (I-V characteristics) measurements have been used to study the electrical properties of virgin and Ar"+ implanted CR-39 specimens. The current has been found to be increased with increasing voltage as well as with increasing ion dose. The dielectric spectroscopy of these specimens has been done in the frequency range of 100 kHz-100 MHz. The dielectric constant has been found to be decreasing whereas dielectric loss factor increases with increasing ion fluence. These kind of behavior observed in the implanted specimens indicate towards the formation of carbonaceous clusters due to the cross linking, chemical bond cleavage, formation of free radicals. The changes observed in the dielectric behavior have been further correlated with the structural changes observed through I-V characteristics.

  10. Longitudinally Controlled Modification of Cylindrical and Conical Track-Etched Poly(ethylene terephthalate) Pores Using an Electrochemically Assisted Click Reaction

    International Nuclear Information System (INIS)

    Coceancigh, Herman; Tran-Ba, Khanh-Hoa; Columbia University, New York, NY; Siepser, Natasha; Baker, Lane A.; Ito, Takashi

    2017-01-01

    Here in this study, the longitudinally controlled modification of the inner surfaces of poly(ethylene terephthalate) (PET) track-etched pores was explored using an electrochemically assisted Cu(I)-catalyzed azide–alkyne cycloaddition (CuAAC) click reaction. Cylindrical or conical PET track-etched pores were first decorated with ethynyl groups via the amidation of surface -COOH groups, filled with a solution containing Cu(II) and azide-tagged fluorescent dye, and then sandwiched between comb-shaped and planar gold electrodes. Cu(I) was produced at the comb-shaped working electrode by the reduction of Cu(II); it diffused along the pores toward the other electrode and catalyzed CuAAC between an azide-tagged fluorescent dye and a pore-tethered ethynyl group. The modification efficiency of cylindrical pores (ca. 1 μm in diameter) was assessed from planar and cross-sectional fluorescence microscope images of modified membranes. Planar images showed that pore modification took place only above the teeth of the comb-shaped electrode with a higher reaction yield for longer Cu(II) reduction times. Cross-sectional images revealed micrometer-scale gradient modification along the pore axis, which reflected a Cu(I) concentration profile within the pores, as supported by finite-element computer simulations. The reported approach was applicable to the asymmetric modification of cylindrical pores with two different fluorescent dyes in the opposite directions and also for the selective visualization of the tip and base openings of conical pores (ca. 3.5 μm in base diameter and ca. 1 μm in tip diameter). Lastly, the method based on electrochemically assisted CuAAC provides a controlled means to fabricate asymmetrically modified nanoporous membranes and, in the future, will be applicable for chemical separations and the development of sequential catalytic reactors.

  11. Analysis of etchants behavior on the electrochemical etching amplification of fast-neutron-induced recoil particle tracks in polycarbonate

    International Nuclear Information System (INIS)

    Masnadi Shirazi Nezhad, K.

    1979-08-01

    The composition, concentration, and temperature of etchant are important parameters controlling electrochemical etching (ECE) amplification of charged particle tracks in polymers. These parameters were further studied for sohralir polycarbonate neutron dosimeter (Sohrabi 1974), using potassium hydroxide (KOH) and sodium hydroxide (NaOH) solutions, and a mixture of potassium hydroxide, ethanol, and water (PEW solution), at different concentrations applying a field strength of 32KV/cm at 2KHz frequency using 250 μ thick polycarbonate exposed to fast neutrons. The recoal track density per rad of neutrons, in general, was found to increase by increasing the etchant concentration reaching a semi-platean after which it increases again. This increase is up to a concentration at which a track removing process occurs and no tracks have been amplified anymore. This track removing process occurred at about 11 normality in both KOH (50% by weight) and NaOH (30% by weight) solution at 25degC. The mean track diameter, in general, passed through a cyclic variation having a maximun and a minimum. For NaOH solution, the track removing process occurred at the minimum point. In the three regions of the track diameter curve the tracks appear in different shapes especially in KOH solution. The PEW solution at its optimum conditions was more effective in terms of both sensitivity, track diameter and a shorter period of etching. The chemical mechanism of etching process may be explained to be a ''saponification'' process. These studies further support the adequacy of Sohrabi dosimeter for routing health physics and radiation research applications. The above parameters are further discussed and the results as well as the advantages and disadvantages of the above etchants are given. (author)

  12. Vacuum pump age effects by the exposure to the corrosive gases on the Cr etch rate as observed using optical emission spectroscopy in an Ar/O{sub 2}/Cl{sub 2} mixed plasma

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seolhye; Roh, Hyun-Joon; Jang, Yunchang; Jeong, Sangmin; Ryu, Sangwon; Choe, Jae-Myung; Kim, Gon-Ho, E-mail: ghkim@snu.ac.kr

    2016-03-31

    Vacuum pumps of different ages were used to prepare Cl{sub 2} based plasmas for use in Cr etching. The effects of the vacuum pump age on the etching results were investigated using optical emission spectroscopy analysis. The composition of gas at the base pressure was mainly nitrogen and oxygen, although the ratio depended on the vacuum pump age and therefore, modulated the etch rate in a manner that was difficult to monitor. The effects of the pump age on the etch rate were clearly observed in the Cl{sub 2} plasma-assisted chromium film etching process, in which oxygen and chlorine radicals were responsible for the etching process. The electron energy distribution function (EEDF), which provided a proxy for the thermal equilibrium properties of the etching plasmas, was monitored. The shape of EEDF was derived from an analysis of the optical emission spectral data using an analysis model described previously. Because molecular nitrogen has a higher threshold energy and a larger cross-section of inelastic collisional processes than oxygen, the tail of the EEDF depends on the mixing ratio between nitrogen and oxygen. The various mechanisms that contribute to the chromium etch rate varied with subtle differences in the vacuum conditions, which were determined by age of the turbo molecular pump. The rates at which oxygen and chlorine radicals were generated were estimated using the measured EEDF, and the estimated oxygen radical and etching product contents were verified by comparing the residual gas analyzer data. The results revealed that the residual nitrogen partial pressures in two etchers equipped with either a new or an aged pump differed by 0.18%, and the EEDF tail areas differed by 10{sup −4}. Importantly, the chromium etch rates in these two instruments differed by 30%. These results suggest that the chamber-to-chamber mismatch should be monitored during plasma-assisted device fabrication processes. - Highlights: • We observed the vacuum pump age effect

  13. Calibrations of CR39 and Makrofol nuclear track detectors and search for exotic particles

    CERN Document Server

    Ambrosio, M; Auriemma, G; Bakari, D; Baldini, A; Barbarino, G C; Barish, B C; Battistoni, G; Becherini, Y; Bellotti, R; Bemporad, C; Bernardini, P; Bilokon, H; Bloise, C; Bower, C; Brigida, M; Bussino, S; Cafagna, F; Calicchio, M; Campana, D; Carboni, M; Caruso, R; Cecchini, S; Cei, F; Chiarella, V; Chiarusi, T; Choudhary, B C; Coutu, S; Cozzi, M; De Cataldo, G; De Marzo, C; De Mitri, I; De Vincenzi, M; Dekhissi, H; Derkaoui, J; Di Credico, A; Erriquez, O; Favuzzi, C; Forti, C; Fusco, P; Giacomelli, G; Giannini, G; Giglietto, N; Giorgini, M; Grassi, M; Grillo, A; Guarino, F; Gustavino, C; Habig, A; Hanson, K; Heinz, R; Iarocci, E; Katsavounidis, E; Katsavounidis, I; Kearns, E; Kim, H; Kumar, A; Kyriazopoulou, S; Lamanna, E; Lane, C; Levin, D S; Lipari, P; Longley, N P; Longo, M J; Loparco, F; Maaroufi, F; Mancarella, G; Mandrioli, G; Manzoor, S; Margiotta, A; Marini, A; Martello, D; Marzari-Chiesa, A; Matteuzzi, D; Mazziotta, M N; Michael, D G; Monacelli, P; Montaruli, T; Monteno, M; Mufson, S; Musser, J; Nicolò, D; Nolty, R; Orth, C; Osteria, G; Palamara, O; Patera, V; Patrizii, L; Pazzi, R; Peck, C W; Perrone, L; Petrera, S; Pistilli, P; Popa, V; Rainó, A; Reynoldson, J; Ronga, F; Rrhioua, A; Satriano, C; Scapparone, E; Scholberg, K; Sciubba, A; Serra, P; Sioli, M; Sirri, G; Sitta, M; Spinelli, P; Spinetti, M; Spurio, M; Steinberg, R; Stone, J L; Sulak, L R; Surdo, A; Tarle, G; Togo, V; Vakili, M; Walter, C W; Webb, R; 10.1016/S0920-5632(03)02249-7

    2003-01-01

    We present the final results of the search for exotic massive particles in the cosmic radiation performed with the MACRO underground experiment. Magnetic monopoles and nuclearites flux upper limits obtained with the CR39 nuclear track subdetector, the scintillation and streamer tube subdetectors are given. Searches at high altitude with the SLIM experiment are in progress.

  14. Development of a reader for track etch detectors based on a commercially available slide scanner

    CERN Document Server

    Steele, J D; Tanner, R J; Bartlett, D T

    1999-01-01

    NRPB has operated a routine neutron personal dosimetry service based on the electrochemical etch of PADC elements since 1986. Since its inception it has used an automated reader based on a video camera and real time analysis. A new and more powerful replacement system has been developed using a commercially available photographic slide scanner. This permits a complete image of the dosemeter to be grabbed in a single scan, generating a 2592x3888 pixel file which is saved for subsequent analysis. This gives an effective pixel size of 10x10 mu m with an image of the entire dosemeter in one field of view. Custom written software subsequently analyses the image to assess the number of etched pits on the dosemeter and read the detector identification number (code). Batch scanning of up to 40 detectors is also possible using an autofeed attachment. The system can be used for electrochemically etched tracks for neutron detectors and chemically etched tracks for radon detectors.

  15. Power ultrasound irradiation during the alkaline etching process of the 2024 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Moutarlier, V.; Viennet, R.; Rolet, J.; Gigandet, M.P.; Hihn, J.Y., E-mail: jean-yves.hihn@univ-fcomte.fr

    2015-11-15

    Graphical abstract: Result of an etching step in ultrasound presence on intermetallic particles on a 2024 aluminum alloy. - Highlights: • Etching step prior to anodization on 2024 aluminum alloy. • Etching rate measurement and hydroxide film characterization by GDOES and SEM. • Various etching parameters (temperature, presence or absence of ultrasound). • Improvement of corrosion resistance show by electrochemical tests. - Abstract: Prior to any surface treatment on an aluminum alloy, a surface preparation is necessary. This commonly consists in performing an alkaline etching followed by acid deoxidizing. In this work, the use of power ultrasound irradiation during the etching step on the 2024 aluminum alloy was studied. The etching rate was estimated by weight loss, and the alkaline film formed during the etching step was characterized by glow discharge optical emission spectrometry (GDOES) and scanning electron microscope (SEM). The benefit of power ultrasound during the etching step was confirmed by pitting potential measurement in NaCl solution after a post-treatment (anodizing).

  16. Power ultrasound irradiation during the alkaline etching process of the 2024 aluminum alloy

    International Nuclear Information System (INIS)

    Moutarlier, V.; Viennet, R.; Rolet, J.; Gigandet, M.P.; Hihn, J.Y.

    2015-01-01

    Graphical abstract: Result of an etching step in ultrasound presence on intermetallic particles on a 2024 aluminum alloy. - Highlights: • Etching step prior to anodization on 2024 aluminum alloy. • Etching rate measurement and hydroxide film characterization by GDOES and SEM. • Various etching parameters (temperature, presence or absence of ultrasound). • Improvement of corrosion resistance show by electrochemical tests. - Abstract: Prior to any surface treatment on an aluminum alloy, a surface preparation is necessary. This commonly consists in performing an alkaline etching followed by acid deoxidizing. In this work, the use of power ultrasound irradiation during the etching step on the 2024 aluminum alloy was studied. The etching rate was estimated by weight loss, and the alkaline film formed during the etching step was characterized by glow discharge optical emission spectrometry (GDOES) and scanning electron microscope (SEM). The benefit of power ultrasound during the etching step was confirmed by pitting potential measurement in NaCl solution after a post-treatment (anodizing).

  17. Bonding performance of universal adhesives to er,cr:YSGG laser-irradiated enamel.

    Science.gov (United States)

    Ayar, Muhammet Kerim; Erdemir, Fatih

    2017-04-01

    Universal adhesives have been recently introduced for use as self-etch or etch-and-rinse adhesives depending on the dental substrate and clinical condition. However, their bonding effectiveness to laser-irradiated enamel is still not well-known. Thus, the aim of this study was to compare the shear bond strength (SBS) of universal adhesives (Single Bond Universal; Nova Compo-B Plus) applied to Er,Cr:YSGG laser-irradiated enamel with SBS of the same adhesives applied in self-etch and acid-etching modes, respectively. Crown segments of sixty bovine incisors were embedded into standardized acrylic blocks. Flattened enamel surfaces were prepared. Specimens were divided into six groups according to universal adhesives and application modes randomly (n = 10), as follows: Single Bond Universal/acid-etching mode; Nova Compo-B Plus/acid-etching mode; Single Bond Universal/self-etching mode; Nova Compo-B Plus/self-etching mode; and Single Bond Universal/Er,Cr:YSGG Laser-etching mode; Nova Compo-B Plus/Er,Cr:YSGG Laser-etching mode. After surface treatments, universal adhesives were applied onto surfaces. SBS was determined after storage in water for 24 h using a universal testing machine with a crosshead speed of 0.5 mm min -1 . Failure modes were evaluated using a stereomicroscope. Data was analyzed using two-way of analyses of variances (ANOVA) (p = 0.05). Two-way ANOVA revealed that adhesive had no effect on SBS (p = 0.88), but application mode significantly influenced SBS (p = 0.00). Acid-etching significantly increased SBS, whereas there are no significant differences between self-etch mode and laser-etching for both adhesives. The bond strength of universal adhesives may depend on application mode. Acid etching may significantly increase bond strength, while laser etching may provide similar bond strength when compared to self-etch mode. © 2016 Wiley Periodicals, Inc.

  18. Thermal degradation of CR-39 polymer in an inert atmosphere

    International Nuclear Information System (INIS)

    Kalsi, P.C.; Pandey, A.K.; Iyer, R.H.; Singh Mudher, K.D.

    1995-01-01

    The thermal degradation of CR-39 (allyl diglycol carbonate), a polymer widely used in nuclear science and technology, in an inert atmosphere has been studied using thermogravimetric analysis (TGA) and differential thermal analysis (DTA) techniques. The results are compared with the thermal degradation data of the polymer in an air atmosphere. The present studies showed that the thermal degradation of the polymer proceeds in two steps in an argon atmosphere as compared to three steps in air atmosphere. The mass losses in air are higher than that in argon due to the oxidative decomposition of the residue. The kinetics of the different stages of degradation were also evaluated from the TG curves. (author). 7 refs., 1 tab

  19. Characterisation of anisotropic etching in KOH using network etch rate function model: influence of an applied potential in terms of microscopic properties

    International Nuclear Information System (INIS)

    Nguyen, Q D; Elwenspoek, M

    2006-01-01

    Using the network etch rate function model, the anisotropic etch rate of p-type single crystal silicon was characterised in terms of microscopic properties including step velocity, step and terrace roughening. The anisotropic etch rate data needed have been obtained using a combination of 2 wagon wheel patterns on different substrate and 1 offset trench pattern. Using this procedure the influence of an applied potential has been investigated in terms of microscopic properties. Model parameter trends show a good correlation with chemical/electrochemical reaction mechanism and mono- and dihydride terminated steps reactivity difference. Results also indicate a minimum in (111) terrace roughening which results in a peak in anisotropic ratio at the non-OCP applied potential of -1250 mV vs OCP

  20. Can previous acid etching increase the bond strength of a self-etching primer adhesive to enamel?

    Directory of Open Access Journals (Sweden)

    Ana Paula Morales Cobra Carvalho

    2009-06-01

    Full Text Available Because a greater research effort has been directed to analyzing the adhesive effectiveness of self etch primers to dentin, the aim of this study was to evaluate, by microtensile testing, the bond strength to enamel of a composite resin combined with a conventional adhesive system or with a self-etching primer adhesive, used according to its original prescription or used with previous acid etching. Thirty bovine teeth were divided into 3 groups with 10 teeth each (n= 10. In one of the groups, a self-etching primer (Clearfil SE Bond - Kuraray was applied in accordance with the manufacturer's instructions and, in the other, it was applied after previous acid etching. In the third group, a conventional adhesive system (Scotchbond Multipurpose Plus - 3M-ESPE was applied in accordance with the manufacturer's instructions. The results obtained by analysis of variance revealed significant differences between the adhesive systems (F = 22.31. The self-etching primer (Clearfil SE Bond presented lower enamel bond strength values than the conventional adhesive system (Scotchbond Multipurpose Plus (m = 39.70 ± 7.07 MPa both when used according to the original prescription (m = 27.81 ± 2.64 MPa and with previous acid etching (m = 25.08 ± 4.92 MPa.

  1. The development of an automatic scanning method for CR-39 neutron dosimeter

    International Nuclear Information System (INIS)

    Tawara, Hiroko; Miyajima, Mitsuhiro; Sasaki, Shin-ichi; Hozumi, Ken-ichi

    1989-01-01

    A method of measuring low level neutron dose has been developed with CR-39 track detectors using an automatic scanning system. It is composed of the optical microscope with a video camera, an image processor and a personal computer. The focus point of the microscope and the X-Y stage are controlled from the computer. The minimum detectable neutron dose is estimated at 4.6 mrem in the uniform field of neutron with equivalent energy spectrum to Am-Be source from the results of automatic measurements. (author)

  2. Alpha activity of 190 Pt isotope measured with CR-39 track detector

    International Nuclear Information System (INIS)

    Tavares, O.A.P.; Terranova, M.L.

    1996-11-01

    A new method to measure alpha activity of long-lived radioisotopes is reported. The method consists basically in using CR-39 track detectors in close contact with thick samples of the radioelement to be investigated. Accordingly, a long-term exposure experiment has been performed using metallic sheets of natural platinum to measure alpha activity of platinum 190 isotope. The half-life of platinum 190 has been obtained in good agreement with two recent theoretical half-life predictions. (author). 21 refs., 3 figs., 2 tabs

  3. Electrochemical hydrogen storage in ZrCrNiPd{sub x} alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, F.C. [Centro Atomico Bariloche (CAB), Comision Nacional de Energia Atomica (CNEA), C. P. 8400, S. C. de Bariloche (RN) (Argentina); CONICET Consejo Nacional de Investigaciones Cientificas y Tecnicas, Av. Rivadavia 1917, C1033AAJ, Ciudad de Buenos Aires (Argentina); Peretti, H.A. [Centro Atomico Bariloche (CAB), Comision Nacional de Energia Atomica (CNEA), C. P. 8400, S. C. de Bariloche (RN) (Argentina); Instituto Balseiro, Universidad Nacional de Cuyo, C. P. 8400, S. C. de Bariloche (RN) (Argentina); Visintin, A. [CONICET Consejo Nacional de Investigaciones Cientificas y Tecnicas, Av. Rivadavia 1917, C1033AAJ, Ciudad de Buenos Aires (Argentina); Instituto de Investigaciones Fisicoquimicas, Teoricas y Aplicadas, Universidad Nacional de La Plata, Suc. 4, C.C.: 16/Comision de Investigaciones Cientificas Provincia de Buenos Aires (C.I.C.), CP: 1900, La Plata (Argentina)

    2010-06-15

    The consumption of rechargeable batteries at worldwide level has increased constantly in the last years, mainly due to the use of portable devices such as cellular phones, digital cameras, computers, music and video reproducers, etc. Nickel Metal Hydride (NiMH) is a rechargeable battery system widely used in these devices, also including the most of electrical and hybrid vehicles (EV and HEV). The study of hydride forming alloys is fundamental for its use as negative electrode component in NiMH batteries. In previous works, the electrocatalytic effect of Pd element addition to the electrode, in powder form and by means of electroless technique, has been studied. In this work, AB{sub 2}-type alloys are studied, in which Pd is incorporated to the structure by re-melting inside an arc furnace. The base alloy composition is ZrCrNi, and the composition of the elaborated compounds is ZrCrNiPd{sub x} (x = 0.095 and 0.19). The effect of the composition modification on these materials on properties such as electrochemical discharge capacity, activation and high rate dischargeability (HRD) is analyzed. (author)

  4. Chemical etching studies of a Brazilian polycarbonate to fast neutron detection

    International Nuclear Information System (INIS)

    Souto, E.B.; Campos, L.L.

    2006-01-01

    The Dosimetric Materials Laboratory (LMD) of the Radiation Metrology Center (CMR) is developing a personal dosimeter for fast neutrons using the technique of solid state nuclear track detectors (SSNTD). This technique is based on the recorded damage (tracks) in dielectric materials due to the impact of charged particles. The tracks are revealed and amplified for visualization in optic microscope through a technique known as chemical etching. The LMD is investigating a Brazilian commercial polycarbonate as a new passive fast neutron's detector in substitution to the traditional materials, as the cellulose nitrate LR-115 and the polycarbonates Makrofol and CR-39. The variation of the etching parameters (chemical solution, time and temperature) alters the response of the material; the best revelation conditions provide the best relationship among the amount of revealed tracks, their clearness and the time spent for this. The polycarbonate studied is a resin of same chemical monomer of Makrofol (C,6H,403). Samples of 3 x 1 cm 2 of the polycarbonate were irradiated with 5 mSv of fast neutrons ( 241 Am-Be) and revealed with the chemical solution PEW-40 (15% KOH, 45% H 2 O, 40% C 2 H 5 OH), commonly used for Makrofol. The studied etching parameters were time and temperature. Groups of four samples were revealed at temperatures of 50, 65, 75, 90 and 100 C with etching times varying from one to six hours. The used track's counting procedure was that referred in the literature. The best response to fast neutrons was obtained at 75 C; in spite of their similar answers, smaller temperatures join larger uncertainties in the track's counting and poorer clearness. At this temperature, the number of revealed tracks increases with the etching time approximately until a plateau at three hours. For etching times higher than four hours the polycarbonate presents overlap of tracks. If the temperature is adjusted to 75 C, the etching time should be in the plateau to avoid that small

  5. Evaluation of the bond strength of resin cements used to lute ceramics on laser-etched dentin.

    Science.gov (United States)

    Giray, Figen Eren; Duzdar, Lale; Oksuz, Mustafa; Tanboga, Ilknur

    2014-07-01

    The purpose of this study was to investigate the shear bond strength (SBS) of two different adhesive resin cements used to lute ceramics on laser-etched dentin. Erbium, chromium: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) laser irradiation has been claimed to improve the adhesive properties of dentin, but results to date have been controversial, and its compatibility with existing adhesive resin cements has not been conclusively determined. Two adhesive cements, one "etch-and-rinse" [Variolink II (V)] and one "self-etch" [Clearfil Esthetic Cement (C)] luting cement, were used to lute ceramic blocks (Vita Celay Blanks, Vita) onto dentin surfaces. In total, 80 dentin specimens were distributed randomly into eight experimental groups according to the dentin surface-etching technique used Er,Cr:YSGG laser and Er:YAG laser: (1) 37% orthophosphoric acid+V (control group), (2) Er,Cr:YSGG laser+V, (3) Er,Cr:YSGG laser+acid+V, (4) Er:YAG laser+V, (5) Er:YAG laser+acid+V, (6) C, (7) Er,Cr:YSGG laser+C, and (8) Er:YAG laser+C. Following these applications, the ceramic discs were bonded to prepared surfaces and were shear loaded in a universal testing machine until fracture. SBS was recorded for each group in MPa. Shear test values were evaluated statistically using the Mann-Whitney U test. No statistically significant differences were evident between the control group and the other groups (p>0.05). The Er,Cr:YSGG laser+A+V group demonstrated significantly higher SBS than did the Er,Cr:YSGG laser+V group (p=0.034). The Er,Cr:YSGG laser+C and Er:YAG laser+C groups demonstrated significantly lower SBS than did the C group (pceramic bond strengths, depending upon the adhesive cement used.

  6. Regular self-microstructuring on CR39 using high UV laser dose

    International Nuclear Information System (INIS)

    Parvin, P.; Refahizadeh, M.; Mortazavi, S.Z.; Silakhori, K.; Mahdiloo, A.; Aghaii, P.

    2014-01-01

    The UV laser induced replicas in the form of self-lining microstructures are created by high dose (with high fluence) ArF laser irradiation on CR39. Microstructures as the self-induced contours, in the form of concentric circles, appear when the laser fluence is well above the ablation threshold. It leads to the regular periodic parallel lines, i.e. circles with large radii having spatial separation 100–200 nm and line width 300–600 nm, where the number of shots increases to achieve higher UV doses. The surface wettability is also investigated after laser texturing to exhibit that a notable hydrophilicity takes place at high doses.

  7. Comparison of Self-Etch Primers with Conventional Acid Etching System on Orthodontic Brackets

    Science.gov (United States)

    Zope, Amit; Zope-Khalekar, Yogita; Chitko, Shrikant S.; Kerudi, Veerendra V.; Patil, Harshal Ashok; Jaltare, Pratik; Dolas, Siddhesh G

    2016-01-01

    Introduction The self-etching primer system consists of etchant and primer dispersed in a single unit. The etching and priming are merged as a single step leading to fewer stages in bonding procedure and reduction in the number of steps that also reduces the chance of introduction of error, resulting in saving time for the clinician. It also results in smaller extent of enamel decalcification. Aim To compare the Shear Bond Strength (SBS) of orthodontic bracket bonded with Self-Etch Primers (SEP) and conventional acid etching system and to study the surface appearance of teeth after debonding; etching with conventional acid etch and self-etch priming, using stereomicroscope. Materials and Methods Five Groups (n=20) were created randomly from a total of 100 extracted premolars. In a control Group A, etching of enamel was done with 37% phosphoric acid and bonding of stainless steel brackets with Transbond XT (3M Unitek, Monrovia, California). Enamel conditioning in left over four Groups was done with self-etching primers and adhesives as follows: Group B-Transbond Plus (3M Unitek), Group C Xeno V+ (Dentsply), Group D-G-Bond (GC), Group E-One-Coat (Coltene). The Adhesive Remnant Index (ARI) score was also evaluated. Additionally, the surface roughness using profilometer were observed. Results Mean SBS of Group A was 18.26±7.5MPa, Group B was 10.93±4.02MPa, Group C was 6.88±2.91MPa while of Group D was 7.78±4.13MPa and Group E was 10.39±5.22MPa respectively. In conventional group ARI scores shows that over half of the adhesive was remaining on the surface of tooth (score 1 to 3). In self-etching primer groups ARI scores show that there was no or minor amount of adhesive remaining on the surface of tooth (score 4 and 5). SEP produces a lesser surface roughness on the enamel than conventional etching. However, statistical analysis shows significant correlation (pbracket bonding after enamel conditioning with any of the SEPs tested. The SEPs used in Groups C (Xeno V

  8. A passive monitor for radon using electrochemical track etch detector

    International Nuclear Information System (INIS)

    Massera, G.E.; Hassib, G.M.; Piesch, E.

    1980-01-01

    A passive, inexpensive monitor for radon detection and dosimetry is described in detail. It consists of a Makrofoil track etch detector inside a diffusion chamber which is sealed by a fibreglass filter through which radon may diffuse while radon daughters and aerosols are retained on the surface of the filter. The α-particle tracks are revealed by etching the Makrofoil in KOH. The lower detection limit of the radon dosimeter is equivalent to a mean dose in the lung of 130 mrem. After an exposure period of 3 months, a mean radon concentration of 0.3 pCi/l can be detected. The instrument is intended for use in a study to measure the long-term radon exposure in buildings in West Germany. (UK)

  9. The effect of gamma dose on the PADC detectors

    International Nuclear Information System (INIS)

    Zaky, M.F.; Youssef, A.A.

    2002-01-01

    The effect of irradiation by 6 0C O gamma rays in the range 0-60 K gray has been examined on CR-39 SSNTDs. The fission fragment tracks diameter were measured using an optical microscope, the bulk etching rate was calculated using the equation V B = D/2 t. The results indicate that, the track diameter is seen increase slowly in the range 0-60 K gray. The bulk etching rate increases almost linearly as the given gamma dose increases up to (22.5 K Gray), at higher doses the bulk etching rate increases exponentially. The exposure of the CR-39 to gamma rays could sensitize the CR-39 plastic and thus improve the Z/P threshold for track registration

  10. Testing Novel CR-39 Detector Deployment System For Identification of Subsurface Fractures, Soda Springs, ID

    Energy Technology Data Exchange (ETDEWEB)

    McLing, Travis [Idaho National Lab. (INL), Idaho Falls, ID (United States); Carpenter, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Brandon, William [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zavala, Bernie [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-06-01

    The Environmental Protection Agency (EPA) has teamed with Battelle Energy Alliance, LLC (BEA) at Idaho National Laboratory (INL) to facilitate further testing of geologic-fracture-identification methodology at a field site near the Monsanto Superfund Site located in Soda Springs, Idaho. INL has the necessary testing and technological expertise to perform this work. Battelle Memorial Institute (BMI) has engaged INL to perform this work through a Work for Others (WFO) Agreement. This study continues a multi-year collaborative effort between INL and EPA to test the efficacy of using field deployed Cr-39 radon in soil portals. This research enables identification of active fractures capable of transporting contaminants at sites where fractures are suspected pathways into the subsurface. Current state of the art methods for mapping fracture networks are exceedingly expensive and notoriously inaccurate. The proposed WFO will evaluate the applicability of using cheap, readily available, passive radon detectors to identify conductive geologic structures (i.e. fractures, and fracture networks) in the subsurface that control the transport of contaminants at fracture-dominated sites. The proposed WFO utilizes proven off-the-shelf technology in the form of CR-39 radon detectors, which have been widely deployed to detect radon levels in homes and businesses. In an existing collaborative EPA/INL study outside of this workscope,. CR-39 detectors are being utilized to determine the location of active transport fractures in a fractured granitic upland adjacent to a landfill site at the Fort Devens, MA that EPA-designated as National Priorities List (NPL) site. The innovative concept of using an easily deployed port that allows the CR-39 to measure the Rn-222 in the soil or alluvium above the fractured rock, while restricting atmospheric Rn-222 and soil sourced Ra from contaminating the detector is unique to INL and EPA approach previously developed. By deploying a series of these

  11. A novel method to recover DD fusion proton CR-39 data corrupted by fast ablator ions at OMEGA and the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Sutcliffe, G. D., E-mail: gdsut@mit.edu; Milanese, L. M.; Orozco, D.; Lahmann, B.; Gatu Johnson, M.; Séguin, F. H.; Sio, H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Park, H.-S.; Rygg, J. R.; Casey, D. T.; Bionta, R.; Turnbull, D. P.; Huntington, C. M.; Ross, J. S. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Zylstra, A. B. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Rosenberg, M. J.; Glebov, V. Yu. [Laboratory for Laser Energetics, Rochester, New York 14623 (United States)

    2016-11-15

    CR-39 detectors are used routinely in inertial confinement fusion (ICF) experiments as a part of nuclear diagnostics. CR-39 is filtered to stop fast ablator ions which have been accelerated from an ICF implosion due to electric fields caused by laser-plasma interactions. In some experiments, the filtering is insufficient to block these ions and the fusion-product signal tracks are lost in the large background of accelerated ion tracks. A technique for recovering signal in these scenarios has been developed, tested, and implemented successfully. The technique involves removing material from the surface of the CR-39 to a depth beyond the endpoint of the ablator ion tracks. The technique preserves signal magnitude (yield) as well as structure in radiograph images. The technique is effective when signal particle range is at least 10 μm deeper than the necessary bulk material removal.

  12. A novel method to recover DD fusion proton CR-39 data corrupted by fast ablator ions at OMEGA and the National Ignition Facility

    International Nuclear Information System (INIS)

    Sutcliffe, G. D.; Milanese, L. M.; Orozco, D.; Lahmann, B.; Gatu Johnson, M.; Séguin, F. H.; Sio, H.; Frenje, J. A.; Li, C. K.; Petrasso, R. D.; Park, H.-S.; Rygg, J. R.; Casey, D. T.; Bionta, R.; Turnbull, D. P.; Huntington, C. M.; Ross, J. S.; Zylstra, A. B.; Rosenberg, M. J.; Glebov, V. Yu.

    2016-01-01

    CR-39 detectors are used routinely in inertial confinement fusion (ICF) experiments as a part of nuclear diagnostics. CR-39 is filtered to stop fast ablator ions which have been accelerated from an ICF implosion due to electric fields caused by laser-plasma interactions. In some experiments, the filtering is insufficient to block these ions and the fusion-product signal tracks are lost in the large background of accelerated ion tracks. A technique for recovering signal in these scenarios has been developed, tested, and implemented successfully. The technique involves removing material from the surface of the CR-39 to a depth beyond the endpoint of the ablator ion tracks. The technique preserves signal magnitude (yield) as well as structure in radiograph images. The technique is effective when signal particle range is at least 10 μm deeper than the necessary bulk material removal.

  13. A novel method to recover DD fusion proton CR-39 data corrupted by fast ablator ions at OMEGA and the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Sutcliffe, G. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Milanese, L. M. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Orozco, D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Lahmann, B. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Gatu Johnson, M. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Séguin, F. H. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Sio, H. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Frenje, J. A. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Li, C. K. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Petrasso, R. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Park, H. -S. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Rygg, J. R. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Casey, D. T. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Bionta, R. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Turnbull, D. P. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Huntington, C. M. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Ross, J. S. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Zylstra, A. B. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA; Rosenberg, M. J. [Laboratory for Laser Energetics, Rochester, New York 14623, USA; Glebov, V. Yu. [Laboratory for Laser Energetics, Rochester, New York 14623, USA

    2016-08-05

    CR-39 detectors are used routinely in inertial confinement fusion (ICF) experiments as a part of nuclear diagnostics. CR-39 is filtered to stop fast ablator ions which have been accelerated from an ICF implosion due to electric fields caused by laser-plasma interactions. In some experiments, the filtering is insufficient to block these ions and the fusion-product signal tracks are lost in the large background of accelerated ion tracks. A technique for recovering signal in these scenarios has been developed, tested, and implemented successfully. The technique involves removing material from the surface of the CR-39 to a depth beyond the endpoint of the ablator ion tracks. The technique preserves signal magnitude (yield) as well as structure in radiograph images. The technique is effective when signal particle range is at least 10 μm deeper than the necessary bulk material removal.

  14. Surface treatment influences electrochemical stability of cpTi exposed to mouthwashes

    International Nuclear Information System (INIS)

    Beline, Thamara; Garcia, Camila S.; Ogawa, Erika S.; Marques, Isabella S.V.; Matos, Adaias O.; Sukotjo, Cortino; Mathew, Mathew T.

    2016-01-01

    The role of surface treatment on the electrochemical behavior of commercially pure titanium (cpTi) exposed to mouthwashes was tested. Seventy-five disks were divided into 15 groups according to surface treatment (machined, sandblasted with Al 2 O 3 , and acid etched) and electrolyte solution (artificial saliva — control, 0.12% chlorhexidine digluconate, 0.05% cetylpyridinium chloride, 0.2% sodium fluoride, and 1.5% hydrogen peroxide) (n = 5). Open-circuit-potential and electrochemical impedance spectroscopy were conducted at baseline and after 7 and 14 days of immersion in each solution. Potentiodynamic test and total weight loss of disks were performed after 14 days of immersion. Scanning electron microscopy, energy dispersive spectroscopy, white light interferometry and profilometry were conducted for surface characterization before and after the electrochemical tests. Sandblasting promoted the lowest polarization resistance (R p ) (P < .0001) and the highest capacitance (CPE) (P < .006), corrosion current density (I corr ) and corrosion rate (P < .0001). In contrast, acid etching increased R p and reduced CPE, independent to the mouthwash; while hydrogen peroxide reduced R p (P < .008) and increased I corr and corrosion rate (P < .0001). The highest CPE values were found for hydrogen peroxide and 0.2% sodium fluoride. Immersion for longer period improved the electrochemical stability of cpTi (P < .05). In conclusion, acid etching enhanced the electrochemical stability of cpTi. Hydrogen peroxide and sodium fluoride reduced the resistance to corrosion of cpTi, independent to the surface treatment. Chlorhexidine gluconate and cetylpyridinium chloride did not alter the corrosive behavior of cpTi. - Highlights: • Acid etching enhanced the electrochemical stability of cpTi. • Hydrogen peroxide and sodium fluoride reduced the corrosion resistance of cpTi. • Chlorhexidine gluconate and cetylpyridinium chloride can be safely used.

  15. Surface treatment influences electrochemical stability of cpTi exposed to mouthwashes

    Energy Technology Data Exchange (ETDEWEB)

    Beline, Thamara [Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Av Limeira, 901, Piracicaba, São Paulo 13414-903 (Brazil); IBTN/Br — Institute of Biomaterials, Tribocorrosion and Nanomedicine, Brazilian Branch (Brazil); Garcia, Camila S. [Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Av Limeira, 901, Piracicaba, São Paulo 13414-903 (Brazil); Ogawa, Erika S. [Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Av Limeira, 901, Piracicaba, São Paulo 13414-903 (Brazil); IBTN/Br — Institute of Biomaterials, Tribocorrosion and Nanomedicine, Brazilian Branch (Brazil); Marques, Isabella S.V. [Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Av Limeira, 901, Piracicaba, São Paulo 13414-903 (Brazil); Matos, Adaias O. [Department of Prosthodontics and Periodontology, Piracicaba Dental School, University of Campinas (UNICAMP), Av Limeira, 901, Piracicaba, São Paulo 13414-903 (Brazil); IBTN/Br — Institute of Biomaterials, Tribocorrosion and Nanomedicine, Brazilian Branch (Brazil); Sukotjo, Cortino [Department of Restorative Dentistry, University of Illinois at Chicago, College of Dentistry, 801 S Paulina, Chicago, IL 60612 (United States); IBTN — Institute of Biomaterials, Tribocorrosion and Nanomedicine (United States); Mathew, Mathew T. [IBTN — Institute of Biomaterials, Tribocorrosion and Nanomedicine (United States); Department of Orthopedic Surgery, Rush University Medical Center, 1611 W Harrison, Chicago, IL 60612 (United States); and others

    2016-02-01

    The role of surface treatment on the electrochemical behavior of commercially pure titanium (cpTi) exposed to mouthwashes was tested. Seventy-five disks were divided into 15 groups according to surface treatment (machined, sandblasted with Al{sub 2}O{sub 3}, and acid etched) and electrolyte solution (artificial saliva — control, 0.12% chlorhexidine digluconate, 0.05% cetylpyridinium chloride, 0.2% sodium fluoride, and 1.5% hydrogen peroxide) (n = 5). Open-circuit-potential and electrochemical impedance spectroscopy were conducted at baseline and after 7 and 14 days of immersion in each solution. Potentiodynamic test and total weight loss of disks were performed after 14 days of immersion. Scanning electron microscopy, energy dispersive spectroscopy, white light interferometry and profilometry were conducted for surface characterization before and after the electrochemical tests. Sandblasting promoted the lowest polarization resistance (R{sub p}) (P < .0001) and the highest capacitance (CPE) (P < .006), corrosion current density (I{sub corr}) and corrosion rate (P < .0001). In contrast, acid etching increased R{sub p} and reduced CPE, independent to the mouthwash; while hydrogen peroxide reduced R{sub p} (P < .008) and increased I{sub corr} and corrosion rate (P < .0001). The highest CPE values were found for hydrogen peroxide and 0.2% sodium fluoride. Immersion for longer period improved the electrochemical stability of cpTi (P < .05). In conclusion, acid etching enhanced the electrochemical stability of cpTi. Hydrogen peroxide and sodium fluoride reduced the resistance to corrosion of cpTi, independent to the surface treatment. Chlorhexidine gluconate and cetylpyridinium chloride did not alter the corrosive behavior of cpTi. - Highlights: • Acid etching enhanced the electrochemical stability of cpTi. • Hydrogen peroxide and sodium fluoride reduced the corrosion resistance of cpTi. • Chlorhexidine gluconate and cetylpyridinium chloride can be safely used.

  16. Effect of different electrolytes on porous GaN using photo-electrochemical etching

    Energy Technology Data Exchange (ETDEWEB)

    Al-Heuseen, K., E-mail: kalhussen@yahoo.com [Nano-Optoelectronics Research Laboratory, School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Hashim, M.R. [Nano-Optoelectronics Research Laboratory, School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Ali, N.K. [Material Innovations and Nanoelectronics Research Group, Faculty of Electrical Engineering, Department of Electronic Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia)

    2011-05-01

    This article reports the properties and the behavior of GaN during the photoelectrochemical etching process using four different electrolytes. The measurements show that the porosity strongly depends on the electrolyte and highly affects the surface morphology of etched samples, which has been revealed by scanning electron microscopy (SEM) images. Peak intensity of the photoluminescence (PL) spectra of the porous GaN samples was observed to be enhanced and strongly depend on the electrolytes. Among the samples, there is a little difference in the peak position indicating that the change of porosity has little influence on the PL peak shift, while it highly affecting the peak intensity. Raman spectra of porous GaN under four different solution exhibit phonon mode E{sub 2} (high), A{sub 1} (LO), A{sub 1} (TO) and E{sub 2} (low). There was a red shift in E{sub 2} (high) in all samples, indicating a relaxation of stress in the porous GaN surface with respect to the underlying single crystalline epitaxial GaN. Raman and PL intensities were high for samples etched in H{sub 2}SO{sub 4}:H{sub 2}O{sub 2} and KOH followed by the samples etched in HF:HNO{sub 3} and in HF:C{sub 2}H{sub 5}OH.

  17. Effect of different electrolytes on porous GaN using photo-electrochemical etching

    International Nuclear Information System (INIS)

    Al-Heuseen, K.; Hashim, M.R.; Ali, N.K.

    2011-01-01

    This article reports the properties and the behavior of GaN during the photoelectrochemical etching process using four different electrolytes. The measurements show that the porosity strongly depends on the electrolyte and highly affects the surface morphology of etched samples, which has been revealed by scanning electron microscopy (SEM) images. Peak intensity of the photoluminescence (PL) spectra of the porous GaN samples was observed to be enhanced and strongly depend on the electrolytes. Among the samples, there is a little difference in the peak position indicating that the change of porosity has little influence on the PL peak shift, while it highly affecting the peak intensity. Raman spectra of porous GaN under four different solution exhibit phonon mode E 2 (high), A 1 (LO), A 1 (TO) and E 2 (low). There was a red shift in E 2 (high) in all samples, indicating a relaxation of stress in the porous GaN surface with respect to the underlying single crystalline epitaxial GaN. Raman and PL intensities were high for samples etched in H 2 SO 4 :H 2 O 2 and KOH followed by the samples etched in HF:HNO 3 and in HF:C 2 H 5 OH.

  18. Effect of different electrolytes on porous GaN using photo-electrochemical etching

    Science.gov (United States)

    Al-Heuseen, K.; Hashim, M. R.; Ali, N. K.

    2011-05-01

    This article reports the properties and the behavior of GaN during the photoelectrochemical etching process using four different electrolytes. The measurements show that the porosity strongly depends on the electrolyte and highly affects the surface morphology of etched samples, which has been revealed by scanning electron microscopy (SEM) images. Peak intensity of the photoluminescence (PL) spectra of the porous GaN samples was observed to be enhanced and strongly depend on the electrolytes. Among the samples, there is a little difference in the peak position indicating that the change of porosity has little influence on the PL peak shift, while it highly affecting the peak intensity. Raman spectra of porous GaN under four different solution exhibit phonon mode E 2 (high), A 1 (LO), A 1 (TO) and E 2 (low). There was a red shift in E 2 (high) in all samples, indicating a relaxation of stress in the porous GaN surface with respect to the underlying single crystalline epitaxial GaN. Raman and PL intensities were high for samples etched in H 2SO 4:H 2O 2 and KOH followed by the samples etched in HF:HNO 3 and in HF:C 2H 5OH.

  19. Oxygen plasma etching of silver-incorporated diamond-like carbon films

    International Nuclear Information System (INIS)

    Marciano, F.R.; Bonetti, L.F.; Pessoa, R.S.; Massi, M.; Santos, L.V.; Trava-Airoldi, V.J.

    2009-01-01

    Diamond-like carbon (DLC) film as a solid lubricant coating represents an important area of investigation related to space devices. The environment for such devices involves high vacuum and high concentration of atomic oxygen. The purpose of this paper is to study the behavior of silver-incorporated DLC thin films against oxygen plasma etching. Silver nanoparticles were produced through an electrochemical process and incorporated into DLC bulk during the deposition process using plasma enhanced chemical vapor deposition technique. The presence of silver does not affect significantly DLC quality and reduces by more than 50% the oxygen plasma etching. Our results demonstrated that silver nanoparticles protect DLC films against etching process, which may increase their lifetime in low earth orbit environment.

  20. Oxygen plasma etching of silver-incorporated diamond-like carbon films

    Energy Technology Data Exchange (ETDEWEB)

    Marciano, F.R., E-mail: fernanda@las.inpe.b [Instituto Nacional de Pesquisas Espaciais (INPE), Laboratorio Associado de Sensores e Materiais (LAS), Av. dos Astronautas 1758, Sao Jose dos Campos, 12227-010, SP (Brazil); Instituto Tecnologico de Aeronautica (ITA), Centro Tecnico Aeroespacial (CTA), Pca. Marechal Eduardo Gomes, 50-Sao Jose dos Campos, 12228-900, SP (Brazil); Bonetti, L.F. [Clorovale Diamantes Industria e Comercio Ltda, Estr. do Torrao de Ouro, 500-Sao Jose dos Campos, 12229-390, SP (Brazil); Pessoa, R.S.; Massi, M. [Instituto Tecnologico de Aeronautica (ITA), Centro Tecnico Aeroespacial (CTA), Pca. Marechal Eduardo Gomes, 50-Sao Jose dos Campos, 12228-900, SP (Brazil); Santos, L.V.; Trava-Airoldi, V.J. [Instituto Nacional de Pesquisas Espaciais (INPE), Laboratorio Associado de Sensores e Materiais (LAS), Av. dos Astronautas 1758, Sao Jose dos Campos, 12227-010, SP (Brazil)

    2009-08-03

    Diamond-like carbon (DLC) film as a solid lubricant coating represents an important area of investigation related to space devices. The environment for such devices involves high vacuum and high concentration of atomic oxygen. The purpose of this paper is to study the behavior of silver-incorporated DLC thin films against oxygen plasma etching. Silver nanoparticles were produced through an electrochemical process and incorporated into DLC bulk during the deposition process using plasma enhanced chemical vapor deposition technique. The presence of silver does not affect significantly DLC quality and reduces by more than 50% the oxygen plasma etching. Our results demonstrated that silver nanoparticles protect DLC films against etching process, which may increase their lifetime in low earth orbit environment.

  1. Plasma surface modification of polypropylene track-etched membrane to improve its performance properties

    Science.gov (United States)

    Kravets, L. I.; Elinson, V. M.; Ibragimov, R. G.; Mitu, B.; Dinescu, G.

    2018-02-01

    The surface and electrochemical properties of polypropylene track-etched membrane treated by plasma of nitrogen, air and oxygen are studied. The effect of the plasma-forming gas composition on the surface morphology is considered. It has been found that the micro-relief of the membrane surface formed under the gas-discharge etching, changes. Moreover, the effect of the non-polymerizing gas plasma leads to formation of oxygen-containing functional groups, mostly carbonyl and carboxyl. It is shown that due to the formation of polar groups on the surface and its higher roughness, the wettability of the plasma-modified membranes improves. In addition, the presence of polar groups on the membrane surface layer modifies its electrochemical properties so that conductivity of plasma-treated membranes increase.

  2. Thermal stability study of Cr/Au contact formed on n-type Ga-polar GaN, N-polar GaN, and wet-etched N-polar GaN surfaces

    International Nuclear Information System (INIS)

    Choi, Yunju; Kim, Yangsoo; Ahn, Kwang-Soon; Kim, Hyunsoo

    2014-01-01

    Highlights: • The Cr/Au contact on n-type Ga-polar (0 0 0 1) GaN, N-polar (0 0 0 −1) GaN, and wet-etched N-polar GaN were investigated. • Thermal annealing led to a significant degradation of contact formed on N-polar n-GaN samples. • Contact degradation was shown to be closely related to the increase in the electrical resistivity of n-GaN. • Out-diffusion of Ga and N atoms was clearly observed in N-polar samples. - Abstract: The electrical characteristics and thermal stability of a Cr/Au contact formed on n-type Ga-polar (0 0 0 1) GaN, N-polar GaN, and wet-etched N-polar GaN were investigated. As-deposited Cr/Au showed a nearly ohmic contact behavior for all samples, i.e., the specific contact resistance was 3.2 × 10 −3 , 4.3 × 10 −4 , and 1.1 × 10 −3 Ω cm 2 for the Ga-polar, flat N-polar, and roughened N-polar samples, respectively. However, thermal annealing performed at 250 °C for 1 min in a N 2 ambient led to a significant degradation of contact, i.e., the contact resistance increased by 186, 3260, and 2030% after annealing for Ga-polar, flat N-polar, and roughened N-polar samples, respectively. This could be due to the different disruption degree of Cr/Au and GaN interface after annealing, i.e., the insignificant interfacial reaction occurred in the Ga-polar sample, while out-diffusion of Ga and N atoms was clearly observed in N-polar samples

  3. Thermal stability study of Cr/Au contact formed on n-type Ga-polar GaN, N-polar GaN, and wet-etched N-polar GaN surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yunju [School of Semiconductor and Chemical Engineering, Semiconductor Physics Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Suncheon Center, Korea Basic Science Institute, Suncheon 540-742 (Korea, Republic of); Kim, Yangsoo [Suncheon Center, Korea Basic Science Institute, Suncheon 540-742 (Korea, Republic of); Ahn, Kwang-Soon, E-mail: kstheory@ynu.ac.kr [School of Chemical Engineering, Yeungnam University, Gyeongsan, Gyeongbuk 712-749 (Korea, Republic of); Kim, Hyunsoo, E-mail: hskim7@jbnu.ac.kr [School of Semiconductor and Chemical Engineering, Semiconductor Physics Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)

    2014-10-30

    Highlights: • The Cr/Au contact on n-type Ga-polar (0 0 0 1) GaN, N-polar (0 0 0 −1) GaN, and wet-etched N-polar GaN were investigated. • Thermal annealing led to a significant degradation of contact formed on N-polar n-GaN samples. • Contact degradation was shown to be closely related to the increase in the electrical resistivity of n-GaN. • Out-diffusion of Ga and N atoms was clearly observed in N-polar samples. - Abstract: The electrical characteristics and thermal stability of a Cr/Au contact formed on n-type Ga-polar (0 0 0 1) GaN, N-polar GaN, and wet-etched N-polar GaN were investigated. As-deposited Cr/Au showed a nearly ohmic contact behavior for all samples, i.e., the specific contact resistance was 3.2 × 10{sup −3}, 4.3 × 10{sup −4}, and 1.1 × 10{sup −3} Ω cm{sup 2} for the Ga-polar, flat N-polar, and roughened N-polar samples, respectively. However, thermal annealing performed at 250 °C for 1 min in a N{sub 2} ambient led to a significant degradation of contact, i.e., the contact resistance increased by 186, 3260, and 2030% after annealing for Ga-polar, flat N-polar, and roughened N-polar samples, respectively. This could be due to the different disruption degree of Cr/Au and GaN interface after annealing, i.e., the insignificant interfacial reaction occurred in the Ga-polar sample, while out-diffusion of Ga and N atoms was clearly observed in N-polar samples.

  4. Electrochemical performance of arc-produced carbon nanotubes as anode material for lithium-ion batteries

    International Nuclear Information System (INIS)

    Yang, Shubin; Song, Huaihe; Chen, Xiaohong; Okotrub, A.V.; Bulusheva, L.G.

    2007-01-01

    The effects of etching process on the morphology, structure and electrochemical performance of arc-produced multiwalled carbon nanotubes (CNTs) as anode material for lithium-ion batteries were systematically investigated by TEM and a variety of electrochemical testing techniques. It was found that the etched CNTs exhibited four times higher reversible capacity than that of raw CNTs, and possessed excellent cyclability with almost 100% capacity retention after 30 cycles. The kinetic properties of three kinds of CNTs electrodes involving the pristine (CNTs-1), etched (CNTs-2) as well as etch-carbonized samples (CNTs-3) were characterized via ac impedance measurement. It was indicated that, after 30 cycles the exchange current density i 0 of etched CNTs ((7.6-7.8) x 10 -3 A cm -2 ) was higher than that of the raw CNTs (5.9 x 10 -3 A cm -2 ), suggesting the electrochemical activity of CNTs was enhanced by the etching treatment. The storage characteristics of the CNTs electrodes at room temperature and 50 o C were particularly compared. It was found that the film resistance on CNTs electrode generally tended to become large with the elongation of storage time, especially storage at high temperature. In comparison with CNTs-1 and CNTs-3, CNTs-2 exhibited more distinctly increase of film resistance, which is related with the surface properties

  5. Synthesis and characterization of hybrid micro/nano-structured NiTi surfaces by a combination of etching and anodizing

    Science.gov (United States)

    Huan, Z.; Fratila-Apachitei, L. E.; Apachitei, I.; Duszczyk, J.

    2014-02-01

    The purpose of this study was to generate hybrid micro/nano-structures on biomedical nickel-titanium alloy (NiTi). To achieve this, NiTi surfaces were firstly electrochemically etched and then anodized in fluoride-containing electrolyte. With the etching process, the NiTi surface was micro-roughened through the formation of micropits uniformly distributed over the entire surface. Following the subsequent anodizing process, self-organized nanotube structures enriched in TiO2 could be superimposed on the etched surface under specific conditions. Furthermore, the anodizing treatment significantly reduced water contact angles and increased the surface free energy compared to the surfaces prior to anodizing. The results of this study show for the first time that it is possible to create hybrid micro/nano-structures on biomedical NiTi alloys by combining electrochemical etching and anodizing under controlled conditions. These novel structures are expected to significantly enhance the surface biofunctionality of the material when compared to conventional implant devices with either micro- or nano-structured surfaces.

  6. Synthesis and characterization of hybrid micro/nano-structured NiTi surfaces by a combination of etching and anodizing

    International Nuclear Information System (INIS)

    Huan, Z; Fratila-Apachitei, L E; Apachitei, I; Duszczyk, J

    2014-01-01

    The purpose of this study was to generate hybrid micro/nano-structures on biomedical nickel–titanium alloy (NiTi). To achieve this, NiTi surfaces were firstly electrochemically etched and then anodized in fluoride-containing electrolyte. With the etching process, the NiTi surface was micro-roughened through the formation of micropits uniformly distributed over the entire surface. Following the subsequent anodizing process, self-organized nanotube structures enriched in TiO 2 could be superimposed on the etched surface under specific conditions. Furthermore, the anodizing treatment significantly reduced water contact angles and increased the surface free energy compared to the surfaces prior to anodizing. The results of this study show for the first time that it is possible to create hybrid micro/nano-structures on biomedical NiTi alloys by combining electrochemical etching and anodizing under controlled conditions. These novel structures are expected to significantly enhance the surface biofunctionality of the material when compared to conventional implant devices with either micro- or nano-structured surfaces. (paper)

  7. Synthesis and characterization of hybrid micro/nano-structured NiTi surfaces by a combination of etching and anodizing.

    Science.gov (United States)

    Huan, Z; Fratila-Apachitei, L E; Apachitei, I; Duszczyk, J

    2014-02-07

    The purpose of this study was to generate hybrid micro/nano-structures on biomedical nickel-titanium alloy (NiTi). To achieve this, NiTi surfaces were firstly electrochemically etched and then anodized in fluoride-containing electrolyte. With the etching process, the NiTi surface was micro-roughened through the formation of micropits uniformly distributed over the entire surface. Following the subsequent anodizing process, self-organized nanotube structures enriched in TiO2 could be superimposed on the etched surface under specific conditions. Furthermore, the anodizing treatment significantly reduced water contact angles and increased the surface free energy compared to the surfaces prior to anodizing. The results of this study show for the first time that it is possible to create hybrid micro/nano-structures on biomedical NiTi alloys by combining electrochemical etching and anodizing under controlled conditions. These novel structures are expected to significantly enhance the surface biofunctionality of the material when compared to conventional implant devices with either micro- or nano-structured surfaces.

  8. Combining retraction edge lithography and plasma etching for arbitrary contour nanoridge fabrication

    Science.gov (United States)

    Zhao, Yiping; Jansen, Henri; de Boer, Meint; Berenschot, Erwin; Bouwes, Dominique; Gironès, Miriam; Huskens, Jurriaan; Tas, Niels

    2010-09-01

    Edge lithography in combination with fluorine-based plasma etching is employed to avoid the dependence on crystal orientation in single crystal silicon to create monolithic nanoridges with arbitrary contours. This is demonstrated by using a mask with circular structures and Si etching at cryogenic temperature with SF6+O2 plasma mixtures. Initially, the explored etch recipe was used with Cr as the masking material. Although nanoridges with perfect vertical sidewalls have been achieved, Cr causes severe sidewall roughness due to line edge roughness. Therefore, an SU-8 polymer is used instead. Although the SU-8 pattern definition needs further improvement, we demonstrate the possibility of fabricating Si nanoridges of arbitrary contours providing a width below 50 nm and a height between 25 and 500 nm with smooth surface finish. Artifacts in the ridge profile are observed and are mainly caused by the bird's beak phenomenon which is characteristic for the used LOCOS process.

  9. Neutron response study using PADC

    International Nuclear Information System (INIS)

    El-Badry, B.A; Hegazy, T.M; Morsy, A.A.; Zaki, M.F.

    2007-01-01

    The results of an experimental work aimed at improving the performances of the Cr-39 nuclear track detector for neutron dosimetry applications. So, a set of Cr-39 plastic detectors was exposed to 252 Cf neutron source, which has the emission rate of 0.68 x 10 8 s ( -1), and neutron dose equivalent rate 1m apart from the source is equal to 3.8 mrem/h. The detection of fast neutrons performed with Cr-39 detector foils, subsequent chemical etching and evaluation of the etched tracks by an automatic track counting system was studied. It is found that the track density grows with the increase of neutron dose and etching time. These results. are compared with previous work. It is found that there is a matching and good agreement with their investigations

  10. Application of combined TLD and CR-39 PNTD method for measurement of total dose and dose equivalent on ISS

    International Nuclear Information System (INIS)

    Benton, E.R.; Deme, S.; Apathy, I.

    2006-01-01

    To date, no single passive detector has been found that measures dose equivalent from ionizing radiation exposure in low-Earth orbit. We have developed the I.S.S. Passive Dosimetry System (P.D.S.), utilizing a combination of TLD in the form of the self-contained Pille TLD system and stacks of CR-39 plastic nuclear track detector (P.N.T.D.) oriented in three mutually orthogonal directions, to measure total dose and dose equivalent aboard the International Space Station (I.S.S.). The Pille TLD system, consisting on an on board reader and a large number of Ca 2 SO 4 :Dy TLD cells, is used to measure absorbed dose. The Pille TLD cells are read out and annealed by the I.S.S. crew on orbit, such that dose information for any time period or condition, e.g. for E.V.A. or following a solar particle event, is immediately available. Near-tissue equivalent CR-39 P.N.T.D. provides Let spectrum, dose, and dose equivalent from charged particles of LET ∞ H 2 O ≥ 10 keV/μm, including the secondaries produced in interactions with high-energy neutrons. Dose information from CR-39 P.N.T.D. is used to correct the absorbed dose component ≥ 10 keV/μm measured in TLD to obtain total dose. Dose equivalent from CR-39 P.N.T.D. is combined with the dose component <10 keV/μm measured in TLD to obtain total dose equivalent. Dose rates ranging from 165 to 250 μGy/day and dose equivalent rates ranging from 340 to 450 μSv/day were measured aboard I.S.S. during the Expedition 2 mission in 2001. Results from the P.D.S. are consistent with those from other passive detectors tested as part of the ground-based I.C.C.H.I.B.A.N. intercomparison of space radiation dosimeters. (authors)

  11. Electrochemical properties of the passive film on bulk Zr–Fe–Cr intermetallic fabricated by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Yakui [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Ling, Yunhan, E-mail: yhling@mail.tsinghua.edu.cn [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Lai, Wensheng [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Xing, Shupei; Ma, Wen [School of Materials Science and Engineering, Inner Mongolia University of Technology, Huhhot 010051 (China)

    2016-12-01

    Highlights: • SPS was employed to prepare Zr-based intermetallics which were commonly existed in zircaloy. • Zr-based intermetallics act as cathode when they embedded in zirconium matrix. • The passive films on surface of intermetallics behaved as n-type semiconductors. • Carrier concentration of Zr(Fe{sub 3}Cr){sub 2} was much lower than that of other intermetallics. - Abstract: Although Zr-based second phase particles (SPPs) are important factors influencing corrosion resistance of zircaloy cladding materials, the corrosion behavior of SPPs has not been investigated by means of electrochemical method so far. In order to clarify the role of SPPs commonly existed in zircaloy, bulk Zr-based intermetallics were firstly fabricated by spark plasma sintering (SPS) at temperatures 1373 K and an applied pressure of 60 MPa in this work. Both the natural passive film on surface and oxidation behavior of intermetallic has been investigated in this work. X-ray diffraction (XRD) pattern showed that as-prepared intermetallic of crystal structure belongs to Laves phase with AB{sub 2} type. Electrochemical measurement of passive film on surface of bulk Zr-based intermetallic exhibited significant difference with that of zirconium. Potentiodynamic measurements results revealed that intermetallic exhibited higher corrosion potential and lower corrosion current density than that of pure zirconium, implying that Zr-based second phase will act as cathode when they are included in zirconium matrix. Meanwhile, significant improvement of Zr–Fe–Cr intermetallic on the water chemistry corrosion resistance was demonstrated comparing with Zr–Fe and Zr–Cr binary intermetallics.

  12. Electrochemical Methods for the Intergranular Corrosion Property Evaluation of Stainless Steels

    International Nuclear Information System (INIS)

    Lee, Jung Bok

    1987-01-01

    For the last fifteen years, the Electrochemical Potentiokinetic Reactivation (EPR) method, an electrochemical method, has been actively investigated for use in determining the degree of sensitization (DOS) in stainless steels (a metallurgical structure susceptible to intergranular corrosion). One of the reasons for this active investigation was due to the fact that the technique may be usable for field nondestructive measurements of DOS in stainless steels. In this paper, a brief overview of the technique, including the advantages and limitations, is discussed. Then, a new test method which is able to detect the sensitized metallurgical structures nondestructively after field welding is introduced. This new nondestructive method is a modification of the ASTM A262-A (the oxalic acid etch test). The improved test method employs a 30 second etching in a 10% oxalic acid solution under an anodic current density of 1 ampere per square centimeter at the temperatures above 60 .deg. C. Between 50 and 60 .deg. C the thirty second etching test should be used first. When the thirty second etching shows an under etched grain boundary, the etching time should be increased to ninety seconds. At temperatures below 50 .deg. C the ninety second etching, as described in ASTM A 262-A, should be employed. This improved test method can be used in the temperature range of 0 and 100 .deg. C

  13. Effects of polymer corrosion inhibitor on widening etch tunnels of aluminum foil for capacitor

    International Nuclear Information System (INIS)

    Ban, Chaolei; He, Yedong; Shao, Xin; Wang, Zhishen

    2014-01-01

    Highlights: •With PSSA, the exterior surface dissolution of etched Al foil is suppressed. •With PSSA, the interior surface dissolution of etched Al foil is facilitated. •With PSSA, the tunnels are widened along the entire length. •With PSSA, the area and capacitance of etched Al foil are significantly improved. -- Abstract: We investigated the effects of polymeric corrosion inhibitor polystyrene sulfonic acid (PSSA) additive to 3% HNO 3 solution on widening tunnels of pre-etched aluminum foil by electrochemical DC etching for aluminum electrolytic capacitors, using scanning electron microscopy and polarization curves. With trace PSSA, the dissolution of exterior surface of etch tunnels of Al foil is suppressed and the dissolution of interior surface of etch tunnels of Al foil is facilitated, respectively. The tunnels transform from circular cone to circular column in shape and pits-merging on the surface is weakened, leading to significant increase in the surface area and specific capacitance of the Al foil. The amounts of reduced thickness and weight of Al foil during the widening process of etch tunnels can be decreased if PSSA is employed

  14. Morphology of resin-dentin interfaces after Er,Cr:YSGG laser and acid etching preparation and application of different bonding systems.

    Science.gov (United States)

    Beer, Franziska; Buchmair, Alfred; Körpert, Wolfram; Marvastian, Leila; Wernisch, Johann; Moritz, Andreas

    2012-07-01

    The goal of this study was to show the modifications in the ultrastructure of the dentin surface morphology following different surface treatments. The stability of the adhesive compound with dentin after laser preparation compared with conventional preparation using different bonding agents was evaluated. An Er,Cr:YSGG laser and 36% phosphoric acid in combination with various bonding systems were used. A total of 100 caries-free human third molars were used in this study. Immediately after surgical removal teeth were cut using a band saw and 1-mm thick dentin slices were created starting at a distance of 4 mm from the cusp plane to ensure complete removal of the enamel. The discs were polished with silicon carbide paper into rectangular shapes to a size of 6 × 4 mm (±0,2 mm).The discs as well as the remaining teeth stumps were stored in 0.9% NaCl at room temperature. The specimens were divided into three main groups (group I laser group, group II etch group, group III laser and etch group) and each group was subdivided into three subgroups which were allocated to the different bonding systems (subgroup A Excite, subgroup B Scotchbond, subgroup C Syntac). Each disc and the corresponding tooth stump were treated in the same way. After preparation the bonding composite material was applied according to the manufacturers' guidelines in a hollow tube of 2 mm diameter to the disc as well as to the corresponding tooth stump. Shear bond strength testing and environmental scanning electron microscopy were used to assess the morphology and stability of the resin-dentin interface. The self-etching bonding system showed the highest and the most constant shear values in all three main groups, thus enabling etching with phosphoric acid after laser preparation to be avoided. Thus we conclude that laser preparation creates a surface texture that allows prediction of the quality of the restoration without the risk of negative influences during the following treatment steps. This

  15. Visible luminescence in photo-electrochemically etched p-type porous silicon: Effect of illumination wavelength

    International Nuclear Information System (INIS)

    Naddaf, M.; Hamadeh, H.

    2010-01-01

    The effect of low power density of ∼5 μWcm - 2 monochromatic light of different wavelengths on the visible photoluminescence (PL) properties of photo-electrochemically formed p-type porous silicon (PS) has been investigated. Tow peak PL red and green is resolved in PS samples etched under blue-green wavelength illumination; 480,533 and 580 nm. It is found that the weight of green PL has maxima for the sample illuminated with 533 nm wavelength whereas, PL spectra of PS prepared under the influence of red illumination or in dark does not exhibit green PL band, but shows considerable enhancement in the red PL peak intensity. Fourier transform infrared (FTIR) spectroscopic analysis reveals the relationship between the structures of chemical bonding in PS and the observed PL behavior. In particular, the PL efficiency is highly affected by the alteration of the relative content of hydride, oxide and hydroxyl species. Moreover, relative content of hydroxyl group with respect to oxide bonding is seen to have strong relationship to the blue PL. Although, the estimated energy gap value of PS samples shows a considerable enlargement with respect to that of bulk c-Si, the FTIR, low temperature PL and Raman measurements and analysis have inconsistency with quantum confinement of PS. (author)

  16. Visible luminescence in photo-electrochemically etched p-type porous silicon: Effect of illumination wavelength

    International Nuclear Information System (INIS)

    Naddaf, M.; Hamadeh, H.

    2009-01-01

    The effect of low power density of ∼ 5 μW/cm 2 monochromatic light of different wavelengths on the visible photoluminescence (PL) properties of photo-electrochemically formed p-type porous silicon (PS) has been investigated. Two-peak PL 'red' and 'green' is resolved in PS samples etched under blue-green wavelength illumination; 480, 533 and 580 nm. It is found that the weight of 'green' PL has maxima for the sample illuminated with 533 nm wavelength. Whereas, PL spectra of PS prepared under the influence of red illumination or in dark does not exhibit 'green' PL band, but shows considerable enhancement in the 'red' PL peak intensity. Fourier transform infrared (FTIR) spectroscopic analysis reveals the relationship between the structures of chemical bonding in PS and the observed PL behavior. In particular, the PL efficiency is highly affected by the alteration of the relative content of hydride, oxide and hydroxyl species. Moreover, relative content of hydroxyl group with respect to oxide bonding is seen to have strong relationship to the blue PL. Although, the estimated energy gap value of PS samples shows a considerable enlargement with respect to that of bulk c-Si, the FTIR, low temperature PL and Raman measurements and analysis have inconsistency with quantum confinement of PS.

  17. Chemical etching studies of a Brazilian polycarbonate to fast neutron detection

    Energy Technology Data Exchange (ETDEWEB)

    Souto, E.B.; Campos, L.L. [Instituto de Pesquisas Energeticas e Nucleares, IPEN- CNEN/SP Radiation Metrology Center (CMR) Av. Prof. Lineu Prestes, 2242 CEP: 05508-000 Sao Paulo - SP (Brazil)]. e-mail: ebsouto@ipen.br

    2006-07-01

    The Dosimetric Materials Laboratory (LMD) of the Radiation Metrology Center (CMR) is developing a personal dosimeter for fast neutrons using the technique of solid state nuclear track detectors (SSNTD). This technique is based on the recorded damage (tracks) in dielectric materials due to the impact of charged particles. The tracks are revealed and amplified for visualization in optic microscope through a technique known as chemical etching. The LMD is investigating a Brazilian commercial polycarbonate as a new passive fast neutron's detector in substitution to the traditional materials, as the cellulose nitrate LR-115 and the polycarbonates Makrofol and CR-39. The variation of the etching parameters (chemical solution, time and temperature) alters the response of the material; the best revelation conditions provide the best relationship among the amount of revealed tracks, their clearness and the time spent for this. The polycarbonate studied is a resin of same chemical monomer of Makrofol (C,6H,403). Samples of 3 x 1 cm{sup 2} of the polycarbonate were irradiated with 5 mSv of fast neutrons ({sup 241}Am-Be) and revealed with the chemical solution PEW-40 (15% KOH, 45% H{sub 2}O, 40% C{sub 2}H{sub 5}OH), commonly used for Makrofol. The studied etching parameters were time and temperature. Groups of four samples were revealed at temperatures of 50, 65, 75, 90 and 100 C with etching times varying from one to six hours. The used track's counting procedure was that referred in the literature. The best response to fast neutrons was obtained at 75 C; in spite of their similar answers, smaller temperatures join larger uncertainties in the track's counting and poorer clearness. At this temperature, the number of revealed tracks increases with the etching time approximately until a plateau at three hours. For etching times higher than four hours the polycarbonate presents overlap of tracks. If the temperature is adjusted to 75 C, the etching time should be in

  18. Use of Image Pro Plus for counting of {alpha} particles tracks in CR-39; Uso do Image Pro Plus para contagem de tracos de particulas {alpha} em CR-39

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, Marcia Valeria F.E. Sa [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Crispim, Verginia Reis [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Gomes, Rogerio dos S.; Gomes, Joana D' Arc R. Lopes, E-mail: mvaleria@cnen.gov.b, E-mail: verginia@con.ufrj.b, E-mail: rogeriog@cnen.gov.b, E-mail: jlopes@cnen.gov.b [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

    2011-10-26

    This paper measured the radon radiations present in NORM samples, through the diffusion chambers which contained a nuclear track detector (CR-39). For automatic counting of those tracks the computer program Image Pro plus was used. This paper reports the application of Image Pro plus for counting the nuclear tracks, coming from the radon radiation present in NORM samples. As the radiation rate of {sup 222}Rn if proportional to the number of these tracks, the methodology allowed to compare the levels of contamination of the analysed samples. Also, tables and graphics are presented with counting results referring to the stage of validation of Image Pro plus

  19. Calculation of depleted uranium concentration in dental fillings samples using the nuclear track detector CR-39

    International Nuclear Information System (INIS)

    Mahdi, K. H.; Subhi, A. T.; Tawfiq, N. F.

    2012-12-01

    The purpose of this study is to determine the concentration of depleted uranium in dental fillings samples, which were obtained some hospital and dental office, sale of materials deployed in Iraq. 8 samples were examined from two different fillings and lead-filling (amalgam) and composite filling (plastic). concentrations of depleted uranium were determined in these samples using a nuclear track detector CR-39 through the recording of the tracks left by of fragments of fission resulting from the reaction 2 38U (n, f). The samples are bombarded by neutrons emitted from the neutron source (2 41A m-Be) with flux of ( 10 5 n. cm- 2. s -1 ). The period of etching to show the track of fission fragments is 5 hours using NaOH solution with normalization (6.25N), and temperature (60 o C ). Concentration of depleted uranium were calculated by comparison with standard samples. The result that obtained showed that the value of the weighted average for concentration of uranium in the samples fillings (5.54± 1.05) ppm lead to thr filling (amalgam) and (5.33±0.6) ppm of the filling composite (plastic). The hazard- index, the absorbed dose and the effective dose for these concentration were determined. The obtained results of the effective dose for each of the surface of the bone and skin (as the areas most affected by this compensation industrial) is (0.56 mSv / y) for the batting lead (amalgam) and (0.54 mSv / y) for the filling composite (plastic). From the results of study it was that the highest rate is the effective dose to a specimen amalgam filling (0.68 mSv / y) which is less than the allowable limit for exposure of the general people set the World Health Organization (WHO), a (1 mSv / y). (Author)

  20. Optical, structural, and chemical properties of CR-39 implanted with 5.2 MeV doubly charged carbon ions

    Science.gov (United States)

    Ali, Dilawar; Butt, M. Z.; Ishtiaq, Mohsin; Waqas Khaliq, M.; Bashir, Farooq

    2016-11-01

    Poly-allyl-diglycol-carbonate (CR-39) specimens were irradiated with 5.2 MeV doubly charged carbon ions using Pelletron accelerator. Ion dose was varied from 5 × 1013 to 5 × 1015 ions cm-2. Optical, structural, and chemical properties were investigated by UV-vis spectroscopy, x-ray diffractometer, and FTIR/Raman spectroscopy, respectively. It was found that optical absorption increases with increasing ion dose. Absorption edge shifts from UV region to visible region. The measured opacity values of pristine and ion implanted CR-39 range from 0.0519 to 4.7959 mm-1 following an exponential growth (9141%) with the increase in ion dose. The values of direct and indirect band gap energy decrease exponentially with an increase in ion dose by 59% and 71%, respectively. However, average refractive index in the visible region increases from 1.443 to 2.864 with an increase in ion dose, by 98%. A linear relation between band gap energy and crystallite size was observed. Both the number of carbon atoms in conjugation length and the number of carbon atoms per cluster increase linearly with the increase in ion dose. FTIR spectra showed that on C+2 ions irradiation, the intensity of all bands decreases gradually without appearance of any new band, indicating degradation of polymer after irradiation. Raman spectra revealed that the density of -CH2- group decreases on C+2 ions irradiation. However, the structure of CR-39 is completely destroyed on irradiation with ion dose 1 × 1015 and 5 × 1015 ions cm-2.

  1. Observation of the inhomogeneous spatial distribution of MeV ions accelerated by the hydrodynamic ambipolar expansion of clusters

    International Nuclear Information System (INIS)

    Kanasaki, Masato; Jinno, Satoshi; Sakaki, Hironao; Faenov, Anatoly Ya.; Pikuz, Tatiana A.; Nishiuchi, Mamiko; Kiriyama, Hiromitsu; Kando, Masaki; Sugiyama, Akira; Kondo, Kiminori; Matsui, Ryutaro; Kishimoto, Yasuaki; Morishima, Kunihiro; Watanabe, Yukinobu; Scullion, Clare; Smyth, Ashley G.; Alejo, Aaron; Doria, Domenico; Kar, Satyabrata; Borghesi, Marco

    2015-01-01

    An inhomogeneous spatial distribution of laser accelerated carbon/oxygen ions produced via the hydrodynamic ambipolar expansion of CO_2 clusters has been measured by using CR-39 detectors. An inhomogeneous etch pits spatial distribution has appeared on the etched CR-39 detector installed on the laser propagation direction, while homogeneous ones are appeared on those installed at 45° and 90° from the laser propagation direction. From the range of ions in CR-39 obtained by using the multi-step etching technique, the averaged energies of carbon/oxygen ions for all directions are determined as 0.78 ± 0.09 MeV/n. The number of ions in the laser propagation direction is about 1.5 times larger than those in other directions. The inhomogeneous etch pits spatial distribution in the laser propagation direction could originate from an ion beam collimation and modulation by the effect of electromagnetic structures created in the laser plasma. - Highlights: • A spatial distribution of ions due to hydrodynamic ambipolar expansion is measured. • The homogeneous ion energy distribution of 0.78 ± 0.09 MeV/n is measured by CR-39. • The number of ions in the laser axis is about 1.5 times larger than other directions.

  2. Fabrication of Microcomponents by Electrochemical Manufacturing: Advanced Feed-Through Metallisation on Silicon and Nickel Micromechanical Resonators

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Heschel, Matthias; Ravnkilde, Jan Tue

    2000-01-01

    Electrochemical processes such as electroplating, wet selective etching (or controlled corrosion) and electroless plating are powerful tools for fabrication of MEMS (Micro ElectroMechanical Systems) products. Especially when the electrochemical processes are used in combination with UV-lithograph......Electrochemical processes such as electroplating, wet selective etching (or controlled corrosion) and electroless plating are powerful tools for fabrication of MEMS (Micro ElectroMechanical Systems) products. Especially when the electrochemical processes are used in combination with UV......, as well as nickel/gold pads for conductive adhesive bonding, are also deposited by electroplating. The second example is a simple, inexpensive, low-temperature electroplating process for fabrication of released, stress-free nickel comb resonators. Since the manufacturing sequence only involves low...

  3. Selective, electrochemical etching of a semiconductor

    Science.gov (United States)

    Dahal, Rajendra P.; Bhat, Ishwara B.; Chow, Tat-Sing

    2018-03-20

    Methods for facilitating fabricating semiconductor structures are provided which include: providing a multilayer structure including a semiconductor layer, the semiconductor layer including a dopant and having an increased conductivity; selectively increasing, using electrochemical processing, porosity of the semiconductor layer, at least in part, the selectively increasing porosity utilizing the increased conductivity of the semiconductor layer; and removing, at least in part, the semiconductor layer with the selectively increased porosity from the multilayer structure. By way of example, the selectively increasing porosity may include selectively, anodically oxidizing, at least in part, the semiconductor layer of the multilayer structure.

  4. Porous siliconformation and etching process for use in silicon micromachining

    Science.gov (United States)

    Guilinger, Terry R.; Kelly, Michael J.; Martin, Jr., Samuel B.; Stevenson, Joel O.; Tsao, Sylvia S.

    1991-01-01

    A reproducible process for uniformly etching silicon from a series of micromechanical structures used in electrical devices and the like includes providing a micromechanical structure having a silicon layer with defined areas for removal thereon and an electrochemical cell containing an aqueous hydrofluoric acid electrolyte. The micromechanical structure is submerged in the electrochemical cell and the defined areas of the silicon layer thereon are anodically biased by passing a current through the electrochemical cell for a time period sufficient to cause the defined areas of the silicon layer to become porous. The formation of the depth of the porous silicon is regulated by controlling the amount of current passing through the electrochemical cell. The micromechanical structure is then removed from the electrochemical cell and submerged in a hydroxide solution to remove the porous silicon. The process is subsequently repeated for each of the series of micromechanical structures to achieve a reproducibility better than 0.3%.

  5. Ion track etching revisited: II. Electronic properties of aged tracks in polymers

    Science.gov (United States)

    Fink, D.; Muñoz Hernández, G.; Cruz, S. A.; Garcia-Arellano, H.; Vacik, J.; Hnatowicz, V.; Kiv, A.; Alfonta, L.

    2018-02-01

    We compile here electronic ion track etching effects, such as capacitive-type currents, current spike emission, phase shift, rectification and background currents that eventually emerge upon application of sinusoidal alternating voltages across thin, aged swift heavy ion-irradiated polymer foils during etching. Both capacitive-type currents and current spike emission occur as long as obstacles still prevent a smooth continuous charge carrier passage across the foils. In the case of sufficiently high applied electric fields, these obstacles are overcome by spike emission. These effects vanish upon etchant breakthrough. Subsequent transmitted currents are usually of Ohmic type, but shortly after breakthrough (during the track' core etching) often still exhibit deviations such as strong positive phase shifts. They stem from very slow charge carrier mobility across the etched ion tracks due to retarding trapping/detrapping processes. Upon etching the track's penumbra, one occasionally observes a split-up into two transmitted current components, one with positive and another one with negative phase shifts. Usually, these phase shifts vanish when bulk etching starts. Current rectification upon track etching is a very frequent phenomenon. Rectification uses to inverse when core etching ends and penumbra etching begins. When the latter ends, rectification largely vanishes. Occasionally, some residual rectification remains which we attribute to the aged polymeric bulk itself. Last not least, we still consider background currents which often emerge transiently during track etching. We could assign them clearly to differences in the electrochemical potential of the liquids on both sides of the etched polymer foils. Transient relaxation effects during the track etching cause their eventually chaotic behaviour.

  6. Radon diffusion in polymer vessels using CR-39 solid state nuclear track detector

    Energy Technology Data Exchange (ETDEWEB)

    Carneiro, Andre Cavalcanti; Menezes, Maria Angela de B.C.; Rocha, Zildete; Pereira, Marcio Tadeu, E-mail: andreccarneiro@gmail.com, E-mail: menezes@cdtn.br, E-mail: zildete@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Santos, Talita de Oliveira; Lara, Evelise Gomes; Braga, Mario Roberto Martins S.S., E-mail: mariomartins@gmail.com, E-mail: evelise.lara@gmail.com, E-mail: talitaolsantos@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

    2015-07-01

    At CDTN/CNEN, the method to determine {sup 226}Ra in several matrices by gamma spectrometry is already established; however, the method should be improved. This paper is about the first step of this improvement. Several polymer vessels were studied verifying the effect of radiolysis on the walls of the vessel. A test about the diffusion of {sup 222}Rn through the walls was carried out using the CR-39 solid state nuclear track detector. The results pointed out that the vessel made up by acrylic material is the best candidate to replace the vessel actually used. (author)

  7. Effect of Cr-sources on performance of Li1.05Cr0.04Mn1.96O4 cathode materials prepared by slurry spray drying method

    International Nuclear Information System (INIS)

    Peng, Z.D.; Jiang, Q.L.; Du, K.; Wang, W.G.; Hu, G.R.; Liu, Y.X.

    2010-01-01

    The effect of Cr-sources on the performance of Li 1.05 Cr 0.04 Mn 1.96 O 4 prepared by slurry spray drying method was studied by adopting three different chromic compounds, Cr 2 O 3 , Cr 2 (SO 4 ) 3 and Cr(CH 3 COO) 3 , respectively. The prepared powder materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), laser particle size analyzer and Brunauer-Emmett-Teller (BET) specific surface area test. Electrochemical performances of these cathode materials were investigated by electrochemical impedance spectroscopy (EIS) and charge-discharge tests with Li/LiCr x Mn 2-x O 4 coin-type batteries. The results indicate that porous spherical particles with average particle size of about 24 μm can be obtained by slurry spray drying process. Using Cr(CH 3 COO) 3 as Cr-source resulted in the better mixing properties, which can make the as-prepared CA-Li 1.05 Cr 0.04 Mn 1.96 O 4 having smaller lattice parameter, smaller grain size and better structure stability, and consequently the obtained sample showed low charge transfer impedance and electrochemical polarization, and exhibited good electrochemical performance at elevated temperature.

  8. Electrochemical and metallurgical characterization of ZrCr{sub 1-x}NiMo{sub x} AB{sub 2} metal hydride alloys

    Energy Technology Data Exchange (ETDEWEB)

    Erika, Teliz [Universidad de la República, Facultad de Ciencias, Laboratorio de Electroquímica Fundamental, Núcleo Interdisciplinario Ingeniería Electroquímica, Igua 4225, CP 11400 Montevideo (Uruguay); Ricardo, Faccio [Universidad de la República, Crystallography, Solid State and Materials Laboratory (Cryssmat-Lab), DETEMA, Centro NanoMat, Polo Tecnológico de Pando, Espacio Interdisciplinario, Facultad de Química, Montevideo (Uruguay); Fabricio, Ruiz [Consejo Nacional de Investigaciones Científicas y Técnicas , CONICET, Av. Rivadavia 1917, C1033AAJ Ciudad de Buenos Aires (Argentina); Centro Atómico Bariloche , Comisión Nacional de Energía Atómica (CAB-CNEA), Av. Bustillo 9500, CP 8400 S.C. de Bariloche, RN (Argentina); Fernando, Zinola [Universidad de la República, Facultad de Ciencias, Laboratorio de Electroquímica Fundamental, Núcleo Interdisciplinario Ingeniería Electroquímica, Igua 4225, CP 11400 Montevideo (Uruguay); and others

    2015-11-15

    The effects of partial replacement of chromium by molybdenum was studied on the structure and electrochemical kinetic properties of ZrCr{sub 1-x}NiMo{sub x}(x = 0.0, 0.3 and 0.6) metal hydride alloys. The arc-melting prepared alloys were metallurgically characterized by X-ray diffraction and energy dispersive spectroscopy microanalysis, which showed AB{sub 2} (with hexagonal C14 structure) and Zr{sub x}Ni{sub y} (Zr{sub 7}Ni{sub 10}, Zr{sub 9}Ni{sub 11}) phases. After a partial substitution of chromium by molybdenum, secondary phases monotonically increase with the C14 unit cell volume indicating that most of molybdenum atoms locate in the B-site. The alloys were electrochemically characterized using charge/discharge cycling, electrochemical impedance spectroscopy and rate capability experiments that allowed the determination of hydriding reaction kinetic parameters. The presence of molybdenum produces a positive effect for hydrogen diffusion in the alloy lattice, and ZrCr{sub 0.7}NiMo{sub 0.3} alloy depicts the better kinetics associated with a fast activation, lower charge transfer resistance and the best high rate discharge behavior. This fact would be related to a lower diffusion time constant and a bigger value of the product between exchange density current and surface active area. There is a trade-off in the amounts of secondary phase and Laves phases in order to improve the kinetic performance. - Highlights: • Metallurgical characterization evidences the presence of Zr{sub x}Ni{sub y} and C14 phases. • The partial replacement of Cr by Mo promotes the segregation of Zr{sub x}Ni{sub y} phase. • The incorporation of molybdenum improves the kinetics for the hydriding process. • Mo produces a decrease in the diffusion time constant.

  9. LLL development of a combined etch track: albedo dosimeter

    International Nuclear Information System (INIS)

    Griffith, R.V.; Fisher, J.C.; Harder, C.A.

    1977-01-01

    The addition of polycarbonate sheet to albedo detectors for electrochemical etching provides a simple, inexpensive way to reduce the spectral sensitivity of the personnel dosimeter without losing the albedo features of sensitivity and ease of automation. The ECEP technique also provides the dosimetrist with the potential for identifying conditions of body orientation that might otherwise lead to significant error in dosimeter evaluation

  10. Autoradiographic measurement of low concentrations of alpha-active nuclides using CR-39 track detectors

    International Nuclear Information System (INIS)

    Freyer, K.; Dietze, K.; Weisse, S.; Kummer, G.

    1991-01-01

    An autoradiographic method for the determination of alpha emission rates from plastic packaging materials for VLSI silicon memory devices based on long-time exposure of the samples on CR-39 detectors has been tested. The lower limit of detection will be strongly influenced by the background of the detector material and amounts at times to 0.002 alpha particles cm -2 h -1 after 200 days exposure. A mathematical method for the interpretation of very low track densities is discussed. The first results of its application are presented. (author)

  11. Detection of fission fragments and alpha particles using the solid trace detector CR-39

    International Nuclear Information System (INIS)

    Santos, R.C.

    1988-01-01

    The technique of detecting charged particles using the solid track detector CR-39 is employed to establish some characteristics of fission fragments and alpha particles emitted from a Cf-252 source. Results are presented and discussed on the following aspects i) distribution of the track diameters; ii) variations on the track diameters to the chemical attack; iii) variations of the chemical attack velocity with respect to concentration and temperature. iv) activation energy of the developping process; v) induction time; vi) critical angle and efficiency on track developping. (A.C.A.S.) [pt

  12. Characterization of stain etched p-type silicon in aqueous HF solutions containing HNO{sub 3} or KMnO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Mogoda, A.S., E-mail: awad_mogoda@hotmail.com [Department of Chemistry, Faculty of Science, Cairo University, Giza (Egypt); Ahmad, Y.H.; Badawy, W.A. [Department of Chemistry, Faculty of Science, Cairo University, Giza (Egypt)

    2011-04-15

    Research highlights: {yields} Stain etching of p-Si in aqueous HF solutions containing HNO{sub 3} or KMnO{sub 4} was investigated. {yields} The electrical conductivity of the etched Si surfaces was measured using impedance technique. {yields} Scanning electron microscope and energy disperse X-ray were used to analyze the etched surfaces. {yields} Etching in aqueous HF solution containing HNO{sub 3} led to formation of a porous silicon layer. {yields} The formation of the porous silicon layer in HF/KMnO{sub 4} was accompanied by deposition of K{sub 2}SiF{sub 6} on the pores surfaces. - Abstract: Stain etching of p-type silicon in hydrofluoric acid solutions containing nitric acid or potassium permanganate as an oxidizing agent has been examined. The effects of etching time, oxidizing agent and HF concentrations on the electrochemical behavior of etched silicon surfaces have been investigated by electrochemical impedance spectroscopy (EIS). An electrical equivalent circuit was used for fitting the impedance data. The morphology and the chemical composition of the etched Si surface were studied using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques, respectively. A porous silicon layer was formed on Si etched in HF solutions containing HNO{sub 3}, while etching in HF solutions containing KMnO{sub 4} led to the formation of a porous layer and simultaneous deposition of K{sub 2}SiF{sub 6} inside the pores. The thickness of K{sub 2}SiF{sub 6} layer increases with increasing the KMnO{sub 4} concentration and decreases as the concentration of HF increases.

  13. Visible luminescence in photo-electrochemically etched p-type porous silicon: Effect of illumination wavelength

    Energy Technology Data Exchange (ETDEWEB)

    Naddaf, M.; Hamadeh, H., E-mail: scientific@aec.org.sy [Department of Physics, Atomic Energy Commission of Syria (AECS), P.O. Box 6091 Damascus (Syrian Arab Republic)

    2009-08-31

    The effect of low power density of {approx} 5 {mu}W/cm{sup 2} monochromatic light of different wavelengths on the visible photoluminescence (PL) properties of photo-electrochemically formed p-type porous silicon (PS) has been investigated. Two-peak PL 'red' and 'green' is resolved in PS samples etched under blue-green wavelength illumination; 480, 533 and 580 nm. It is found that the weight of 'green' PL has maxima for the sample illuminated with 533 nm wavelength. Whereas, PL spectra of PS prepared under the influence of red illumination or in dark does not exhibit 'green' PL band, but shows considerable enhancement in the 'red' PL peak intensity. Fourier transform infrared (FTIR) spectroscopic analysis reveals the relationship between the structures of chemical bonding in PS and the observed PL behavior. In particular, the PL efficiency is highly affected by the alteration of the relative content of hydride, oxide and hydroxyl species. Moreover, relative content of hydroxyl group with respect to oxide bonding is seen to have strong relationship to the blue PL. Although, the estimated energy gap value of PS samples shows a considerable enlargement with respect to that of bulk c-Si, the FTIR, low temperature PL and Raman measurements and analysis have inconsistency with quantum confinement of PS.

  14. Ekonomik Bir Nükleer İz Kazıma Ünitesinin Üretilmesi ve Performansının Test Edilmesi

    Directory of Open Access Journals (Sweden)

    Vahap KARAKILIÇ

    2014-03-01

    Full Text Available Since the inhalation of radon and radon progenies may cause serious health risks such as increase in the incidence of lung cancer, it is important to determine indoor radon concentrations. In the present study, the performance of the etching unit (track-matic, an automatic bath processing appliance for CR-39 nuclear track detectors that we designed as an alternative to conventional Radobath etching unit, was examined. Indoor radon measurements were performed for a 6-weeks period by using CR-39 detectors, which were placed in 10 measurement points in couples at the Süleyman Demirel University campus. At the end of the measurement period the CR-39 detectors were collected and the counting process of alpha traces (recorded by the detectors were fulfilled in the Health Physics Laboratory of Sarayköy Nuclear Research and Training Center (SANAEM in Ankara. At the stage of making the recorded alpha traces visible, for all the detector couples obtained from the measurement points, the film processing of one detector was performed by using the conventional Radobath etching unit in SANAEM laboratory and the bath process of the other CR-39 detector was performed by our device. Then the results of the analyses were compared to each other. Within the limitations of this study it may be concluded that, the track-matic device that we developed, which is approximately 65 times more economical than the current film processing unit Radobath, can be used for chemical etching process of CR-39 detectors

  15. Effect of electrochemical corrosion on the subsurface microstructure evolution of a CoCrMo alloy in albumin containing environment

    International Nuclear Information System (INIS)

    Wang, Zhongwei; Yan, Yu; Su, Yanjing; Qiao, Lijie

    2017-01-01

    Highlights: • Accelerated electrochemical corrosion results in severer plastic deformation with finer grains. • Lower applied potential can increase protein adsorption on sample surfaces. • The tribo-film decreases the shear stresses and relief subsurface deformation. • Tribocorrosion induced passive film can suppress the annihilation of stacking faults. - Abstract: The subsurface microstructures of metallic implants play a key role in bio-tribocorrosion. Due to wear or change of local environment, the implant surface can have inhomogeneous electrochemical corrosion properties. In this work, the effect of electrochemical corrosion conditions on the subsurface microstructure evolution of CoCrMo alloys for artificial joints was investigated. Transmission electron microscope (TEM) was employed to observe the subsurface microstructures of worn areas at different applied potentials in a simulated physiological solution. The results showed that applied potentials could affect the severity of the subsurface deformation not only by changing the surface passivation but also affecting the adsorption of protein on the alloy surface.

  16. Effect of electrochemical corrosion on the subsurface microstructure evolution of a CoCrMo alloy in albumin containing environment

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhongwei; Yan, Yu, E-mail: yanyu@ustb.edu.cn; Su, Yanjing; Qiao, Lijie

    2017-06-01

    Highlights: • Accelerated electrochemical corrosion results in severer plastic deformation with finer grains. • Lower applied potential can increase protein adsorption on sample surfaces. • The tribo-film decreases the shear stresses and relief subsurface deformation. • Tribocorrosion induced passive film can suppress the annihilation of stacking faults. - Abstract: The subsurface microstructures of metallic implants play a key role in bio-tribocorrosion. Due to wear or change of local environment, the implant surface can have inhomogeneous electrochemical corrosion properties. In this work, the effect of electrochemical corrosion conditions on the subsurface microstructure evolution of CoCrMo alloys for artificial joints was investigated. Transmission electron microscope (TEM) was employed to observe the subsurface microstructures of worn areas at different applied potentials in a simulated physiological solution. The results showed that applied potentials could affect the severity of the subsurface deformation not only by changing the surface passivation but also affecting the adsorption of protein on the alloy surface.

  17. Novel single-cell mega-size chambers for electrochemical etching of panorama position-sensitive polycarbonate ion image detectors

    Science.gov (United States)

    Sohrabi, Mehdi

    2017-11-01

    A novel development is made here by inventing panorama single-cell mega-size electrochemical etching (MS-ECE) chamber systems for processing panorama position-sensitive mega-size polycarbonate ion image detectors (MS-PCIDs) of potential for many neutron and ion detection applications in particular hydrogen ions or proton tracks and images detected for the first time in polycarbonates in this study. The MS-PCID is simply a large polycarbonate sheet of a desired size. The single-cell MS-ECE invented consists of two large equally sized transparent Plexiglas sheets as chamber walls holding a MS-PCID and the ECE chamber components tightly together. One wall has a large flat stainless steel electrode (dry cell) attached to it which is directly in contact with the MS-PCID and the other wall has a rod electrode with two holes to facilitate feeding and draining out the etching solution from the wet cell. A silicon rubber washer plays the role of the wet cell to hold the etchant and the electrical insulator to isolate the dry cell from the wet cell. A simple 50 Hz-HV home-made generator provides an adequate field strength through the two electrodes across the MS-ECE chamber. Two panorama single-cell MS-ECE chamber systems (circular and rectangular shapes) constructed were efficiently applied to processing the MS-PCIDs for 4π ion emission image detection of different gases in particular hydrogen ions or protons in a 3.5 kJ plasma focus device (PFD as uniquely observed by the unaided eyes). The panorama MS-PCID/MS-ECE image detection systems invented are novel with high potential for many applications in particular as applied to 4π panorama ion emission angular distribution image detection studies in PFD space, some results of which are presented and discussed.

  18. Synthesis of CaCrO{sub 4} powders for the cathode material of the thermal battery by GNP and electrochemical characteristics of Ca/LiCl-KCl/CaCrO{sub 4} thermal battery system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Whung Whoe

    2000-04-01

    Thermal batteries are one of the devices employing solid electrolyte that are not nonconductive at ambient temperature, and activated by electrochemical reaction when the sufficient heat is supplied to electrolyte to melt. The demand of thermal batteries would be increased because it is cost effective and highly reliable in that no maintenance is necessary, electric power can be generated as necessary and no self discharge unlike the other primary batteries. These thermal batteries are used to the military purposes and satellite communication systems and as an emergency power sources, applied to the important places where power supply should not be interrupted, such as hospital, powder plants, ships and portable communication devices. Therefore, the purpose of this study was focused to obtain the manufacturing technologies of thermal battery on our own, after manufacturing the CaCrO{sub 4} produced by GNP and investigating the electrochemical characteristics of Ca/LiCl-KCl+CaCrO{sub 4}/Ni.

  19. Electrochemical impedance spectroscopy on Co-Cr-Mo alloy in two media simulating physiological liquid. Caractérisation par spectroscopie d'impédance électrochimique d'un alliage de Co-Cr-Mo dans différents milieux simulant le liquide physiologique.

    OpenAIRE

    Geringer , Jean; Normand , Bernard; Diemiaszonek , Robert; Alémany-Dumont , Catherine; Mary , Nicolas

    2007-01-01

    National audience; Co-Cr-Mo is an alloy which allows manufacturing orthopedic implants, especially hip total joint prostheses. This alloy has good tribological and biocompatibility properties. This work aims at studying electrochemical behavior of this alloy. Moreover, measurements reproductibility has been improved: polarization and electrochemical impedance spectroscopy. Measurements have been carried out with phosphate buffered solution and this one containing albumin, 1 g.L-1. Three diffe...

  20. In situ electrochemical etching and examination by SPM of titanate ceramics

    International Nuclear Information System (INIS)

    Thorogood, G.J.; Short, K.T; Zhang, Y.

    2002-01-01

    Full text: The aqueous durability of titanate related ceramics is of great importance for the immobilisation of high level radioactive waste-in order to observe the reaction progress at the solid-liquid interface of these durable ceramics, we have attempted to accelerate the dissolution process via electrochemical means by using a SPM cell with electrochemical capability. The experiment involves placing a titanate ceramic disk (with flat polished surfaces) in the electrochemical cell. The cell is then set up with the ceramic acting as one electrode and another electrode being placed in the solution. In a flow through cell it is possible to select the pH and observe the change, not only in surface morphology as dissolution occurs, but also the frictional characteristics of the surface. The SPM tip plays no role in the electrochemical reaction. We will be presenting results from our work and discussing possible mechanisms for dissolution and future directions of the work. Copyright (2002) Australian Society for Electron Microscopy Inc

  1. Adhesion Strength of TiN Coatings at Various Ion Etching Deposited on Tool Steels Using Cathodic Arc Pvd Technique

    Science.gov (United States)

    Ali, Mubarak; Hamzah, Esah; Ali, Nouman

    Titanium nitride (TiN) widely used as hard coating material was coated on tool steels, namely on high-speed steel (HSS) and D2 tool steel by physical vapor deposition method. The goal of this study was to examine the effect of ion etching with and without titanium (Ti) and chromium (Cr) on the adhesion strength of TiN coatings deposited on tool steels. From the scratch tester, it was observed that by increasing Ti ion etching showed an increase in adhesion strength of the deposited coatings. The coatings deposited with Cr ion etching showed poor adhesion compared with the coatings deposited with Ti ion etching. Scratch test measurements showed that the coating deposited with titanium ion etching for 16 min is the most stable coating and maintained even at the critical load of 66 N. The curve obtained via penetration depth along the scratch trace is linear in the case of HSS, whereas is slightly flexible in the case of D2 tool steel. The coatings deposited on HSS exhibit better adhesion compared with those on D2 tool steel.

  2. Characterization of graphite etched with potassium hydroxide and its application in fast-rechargeable lithium ion batteries

    Science.gov (United States)

    Shim, Jae-Hyun; Lee, Sanghun

    2016-08-01

    Surface-modified graphite for application as an anode material in lithium ion batteries was obtained by etching with KOH under mild conditions without high-temperature annealing. The surface of the etched graphite is covered with many nano-sized pores that act as entrances for lithium ions during the charging process. As compared with pristine graphite and other references such as pitch-coated or etched graphite samples with annealing, our non-annealed etched graphite exhibits excellent electrochemical properties, particularly at fast charging rates of over 2.5 C. While avoidance of the trade-off between increase of irreversible capacity and good rate capability has previously been a main concern in highly porous carbonaceous materials, we show that the slightly larger surface area created by the etching does not induce a significant increase of irreversible capacity. This study shows that it is important to limit the size of pores to the nanometer scale for excellent battery performance, which is possible by etching under relatively mild conditions.

  3. Particularization of alpha contamination using CR-39 track detectors

    Indian Academy of Sciences (India)

    detecting devices and as a passive system to detect alpha contamination on different sur- faces. This work presents ... these plastic detectors can be cut into sizes and shapes according to the specific area that has to be ... of nuclear track materials observed under a microscope, after chemical etching for the same time and ...

  4. Solid state nuclear track detectors in the measurement of alpha to fission branching ratios of heavy actinides

    International Nuclear Information System (INIS)

    Pandey, A.K.; Sharma, R.C.; Padalkar, S.K.; Kalsi, P.C.; Iyer, R.H.

    1992-01-01

    A sequential etching procedure for revelation of alpha and fission tracks in CR-39 was developed and optimized. Using this technique alpha and fission tracks can be differentiated unambiguously because of significant differences in their sizes and etching times. This registration and revelation procedure for alpha and fission tracks may be used for the studies of half lives, alpha to fission branching ratios and identification of radionuclides based on their decay schemes. It has the added advantage that both alpha decay and fission events can be studied using one detector and hence uncertainties related to efficiency, registration geometry, registration times, amount of radionuclides etc can be eliminated or minimized. The effects of neutron, gamma and alpha radiations on the alpha and fission fragment tracks registration and revelation properties of CR-39 detectors [CR-39, CR-39 (DOP)] were also studied. The IR spectra were also studied to find out the nature of chemical changes produced by these radiations on CR-39. (author). 32 refs., 7 figs., 4 tabs

  5. Preparation of scanning tunneling microscopy tips using pulsed alternating current etching

    International Nuclear Information System (INIS)

    Valencia, Victor A.; Thaker, Avesh A.; Derouin, Jonathan; Valencia, Damian N.; Farber, Rachael G.; Gebel, Dana A.; Killelea, Daniel R.

    2015-01-01

    An electrochemical method using pulsed alternating current etching (PACE) to produce atomically sharp scanning tunneling microscopy (STM) tips is presented. An Arduino Uno microcontroller was used to control the number and duration of the alternating current (AC) pulses, allowing for ready optimization of the procedures for both Pt:Ir and W tips using a single apparatus. W tips prepared using constant and pulsed AC power were compared. Tips fashioned using PACE were sharper than those etched with continuous AC power alone. Pt:Ir tips were prepared with an initial coarse etching stage using continuous AC power followed by fine etching using PACE. The number and potential of the finishing AC pulses was varied and scanning electron microscope imaging was used to compare the results. Finally, tip quality using the optimized procedures was verified by UHV-STM imaging. With PACE, at least 70% of the W tips and 80% of the Pt:Ir tips were of sufficiently high quality to obtain atomically resolved images of HOPG or Ni(111)

  6. Preparation of scanning tunneling microscopy tips using pulsed alternating current etching

    Energy Technology Data Exchange (ETDEWEB)

    Valencia, Victor A.; Thaker, Avesh A.; Derouin, Jonathan; Valencia, Damian N.; Farber, Rachael G.; Gebel, Dana A.; Killelea, Daniel R., E-mail: dkillelea@luc.edu [Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W. Sheridan Rd., Chicago, Illinois 60660 (United States)

    2015-03-15

    An electrochemical method using pulsed alternating current etching (PACE) to produce atomically sharp scanning tunneling microscopy (STM) tips is presented. An Arduino Uno microcontroller was used to control the number and duration of the alternating current (AC) pulses, allowing for ready optimization of the procedures for both Pt:Ir and W tips using a single apparatus. W tips prepared using constant and pulsed AC power were compared. Tips fashioned using PACE were sharper than those etched with continuous AC power alone. Pt:Ir tips were prepared with an initial coarse etching stage using continuous AC power followed by fine etching using PACE. The number and potential of the finishing AC pulses was varied and scanning electron microscope imaging was used to compare the results. Finally, tip quality using the optimized procedures was verified by UHV-STM imaging. With PACE, at least 70% of the W tips and 80% of the Pt:Ir tips were of sufficiently high quality to obtain atomically resolved images of HOPG or Ni(111)

  7. A study of CR-39 plastic charged-particle detector replacement by consumer imaging sensors

    Energy Technology Data Exchange (ETDEWEB)

    Plaud-Ramos, K. O.; Freeman, M. S.; Wei, W.; Guardincerri, E.; Bacon, J. D.; Cowan, J.; Durham, J. M.; Huang, D.; Gao, J.; Hoffbauer, M. A.; Morley, D. J.; Morris, C. L.; Poulson, D. C.; Wang, Zhehui, E-mail: zwang@lanl.gov [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2016-11-15

    Consumer imaging sensors (CIS) are examined for real-time charged-particle detection and CR-39 plastic detector replacement. Removing cover glass from CIS is hard if not impossible, in particular for the latest inexpensive webcam models. We show that $10-class CIS are sensitive to MeV and higher energy protons and α-particles by using a {sup 90}Sr β-source with its cover glass in place. Indirect, real-time, high-resolution detection is also feasible when combining CIS with a ZnS:Ag phosphor screen and optics. Noise reduction in CIS is nevertheless important for the indirect approach.

  8. Measurement of fast neutron spectrum using CR-39 detectors and a new image analysis program (autoTRAKn)

    International Nuclear Information System (INIS)

    Paul, Sabyasachi; Tripathy, S.P.; Sahoo, G.S.; Bandyopadhyay, T.; Sarkar, P.K.

    2013-01-01

    An attempt is made to estimate the neutron spectrum using the CR-39 (Solid state nuclear track) detector and a new image analyzing program. For this purpose the earlier developed program (autoTRAK) is modified by introducing the required features such as angular correction for the recoil particles, fluence-to-dose conversion coefficient, detection sensitivity of CR-39 detectors, etc. to make it applicable for neutron spectrometry and dosimetry. This upgraded program (autoTRAK n ) is tested with a mono-energetic source (D–T) and two other standard neutron sources, viz. 241 Am–Be and 252 Cf. The program is validated by reproducing these standard spectra, and comparing with the spectra reported by other investigators using different measuring techniques. The ratios of dose equivalent (H ⁎ (10)) to fluence (Φ) are also estimated from the spectra and are compared with the reference values for these neutron sources. An additional feature of this program is explored for counting high density overlapping tracks more precisely and effectively compared to other commonly used image analyzing softwares. This method is found to be simple and promising, which can always be used as a supplementary measuring technique. The details of the modified program, reproduction and comparison of the neutron spectra, reproducibility of the methodology and example of overlapping track counting are presented and discussed. -- Highlights: •A novel image analysis technique (autoTRAK n ) is developed to evaluate CR-39 detectors used for neutron spectrometry and dosimetry. •The methodology is tested to reproduce three standard neutron spectra, (a) D–T, (b) 241 Am–Be, and (c) 252 Cf. •A good matching is observed between dosimetric values obtained by the program and the available reference values. •The program autoTRAK n is also observed to be efficient to distinguish high density overlapping tracks without any segregation procedure. •The methodology seems to be simple, which

  9. Metal-assisted etch combined with regularizing etch

    Energy Technology Data Exchange (ETDEWEB)

    Yim, Joanne; Miller, Jeff; Jura, Michael; Black, Marcie R.; Forziati, Joanne; Murphy, Brian; Magliozzi, Lauren

    2018-03-06

    In an aspect of the disclosure, a process for forming nanostructuring on a silicon-containing substrate is provided. The process comprises (a) performing metal-assisted chemical etching on the substrate, (b) performing a clean, including partial or total removal of the metal used to assist the chemical etch, and (c) performing an isotropic or substantially isotropic chemical etch subsequently to the metal-assisted chemical etch of step (a). In an alternative aspect of the disclosure, the process comprises (a) performing metal-assisted chemical etching on the substrate, (b) cleaning the substrate, including removal of some or all of the assisting metal, and (c) performing a chemical etch which results in regularized openings in the silicon substrate.

  10. Anodic processes in the chemical and electrochemical etching of Si crystals in acid-fluoride solutions: Pore formation mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Ulin, V. P.; Ulin, N. V.; Soldatenkov, F. Yu., E-mail: f.soldatenkov@mail.ioffe.ru [Ioffe Physical–Technical Institute (Russian Federation)

    2017-04-15

    The interaction of heavily doped p- and n-type Si crystals with hydrofluoric acid in the dark with and without contact with metals having greatly differing work functions (Ag and Pd) is studied. The dependences of the dissolution rates of Si crystals in HF solutions that contain oxidizing agents with different redox potentials (FeCl{sub 3}, V{sub 2}O{sub 5} and CrO{sub 3}) on the type and level of silicon doping are determined. Analysis of the experimental data suggests that valence-band holes in silicon are not directly involved in the anodic reactions of silicon oxidation and dissolution and their generation in crystals does not limit the rate of these processes. It is also shown that the character and rate of the chemical process leading to silicon dissolution in HF-containing electrolytes are determined by the interfacial potential attained at the semiconductor–electrolyte interface. The mechanism of electrochemical pore formation in silicon crystals is discussed in terms of selfconsistent cooperative reactions of nucleophilic substitution between chemisorbed fluorine anions and coordination- saturated silicon atoms in the crystal subsurface layer. A specific feature of these reactions for silicon crystals is that vacant nonbonding d{sup 2}sp{sup 3} orbitals of Si atoms, associated with sixfold degenerate states corresponding to the Δ valley of the conduction band, are involved in the formation of intermediate complexes. According to the suggested model, the pore-formation process spontaneously develops in local regions of the interface under the action of the interfacial potential in the adsorption layer and occurs as a result of the detachment of (SiF{sub 2}){sub n} polymer chains from the crystal. Just this process leads to the preferential propagation of pores along the <100> crystallographic directions. The thermodynamic aspects of pore nucleation and the effect of the potential drop across the interface, conduction type, and free-carrier concentration

  11. Triton and alpha-particle contribution from LiF converter for neutron dosimeter

    CERN Document Server

    Camacho, M E; Balcazar, M

    1999-01-01

    A personnel neutron dosimeter prototype based on chemical and electrochemical etched CR-39 detector, combined with LiF converter, has been calibrated using an ICRP-like phantom, under a heavy-water moderated Californium source neutron spectra; A conversion factor of 1.052+-126 spots cm sup - sup 2 mSv sup - sup 1 was obtained. The sealing properties of the detector holder showed a ten-fold reduction in radon background when it was tested in a high radon atmosphere. A convenient mechanical shock resistance was achieved in LiF converters by sintering to 11 tons pressure LiF powder at 650 deg. C, during one hour.

  12. Registration properties of different types of CR-39 in vacuum conditions of irradiation

    International Nuclear Information System (INIS)

    Golovchenko, A.N.; Tret'yakova, S.P.

    1991-01-01

    Sensitivity change has been studied of different types of CR-39 detectors (Pershore, Tastrak, Intercast, Ma-ND/α) in dependence on holding time of detector in vacuum chamber at the residual pressure P ≅ 2x10 -2 and ≅ 5x10 -3 Pa before their irradiation with alpha particles from thin 238 Pu source and accelerated charged ions with atomic number Z=2-10 and energy of 9.1 MeV/nucleon. Polymer of Intercast Company turned out to be the most stable one to vacuum effect, and detector does not change the sensitivity up to response function REL 200 ≅ 1 MeVxcm 2 xmg -1 in the mentioned experiment conditions. 7 refs.; 3 figs

  13. Discovery of an 'internal heating effect' during electrochemical etching of polymeric dosimeters: a study of polymer characteristics

    International Nuclear Information System (INIS)

    Sohrabi, M.

    1986-01-01

    This paper investigates the importance of the internal heating effect by studying the role of different polymer physical and chemical characteristics (composition, effective foil size, thickness and electrical properties), on the rate of heating or temperature rise responses for cellulose tri-acetate (CTA), cellulose acetate (CA), allyl diglycol carbonate (CR-39), cellulose nitrate (CN), cellulose acetate butyrate (CAB), polyester (PES), polycarbonate (PC) and polyethylene (PE). Efforts have been made to justify the observed effects by different mechanisms such as dielectric loss, electro-osmosis, dielectrophoresis, and electrostriction. (author)

  14. Experimental and Monte Carlo simulation studies of open cylindrical radon monitoring device using CR-39 detector

    Energy Technology Data Exchange (ETDEWEB)

    Rehman, Fazal-ur- E-mail: fazalr@kfupm.edu.sa; Jamil, K.; Zakaullah, M.; Abu-Jarad, F.; Mujahid, S.A

    2003-07-01

    There are several methods of measuring radon concentrations but nuclear track detector cylindrical dosimeters are widely employed. In this investigation, the consequence of effective volumes of the dosimeters on the registration of alpha tracks in a CR-39 detector was studied. In a series of experiments an optimum radius for a CR-39-based open cylindrical radon dosimeter was found to be about 3 cm. Monte Carlo simulation techniques hav been employed to verify the experimental results. In this context, a computer code Monte Carlo simulation dosimetry (MOCSID) was developed. Monte Carlo simulation experiments gave the optimum radius of the dosimeters as 3.0 cm. The experimental results are in good agreement with those obtained by Monte Carlo design calculations. In addition to this, plate-out effects of radon progeny were also studied. It was observed that the contribution of radon progeny ({sup 218}Po and {sup 214}Po) plated-out on the wall of the dosimeters increases with an increase of dosimeter radii and then decrease to 0 at a radius of about 3 cm if a point detector has been installed at the center of the dosimeter base. In the code MOCSID different types of random number generators were employed. The results of this research are very useful for designing an optimum size of radon dosimeters.

  15. Experimental and Monte Carlo simulation studies of open cylindrical radon monitoring device using CR-39 detector

    International Nuclear Information System (INIS)

    Rehman, Fazal-ur-; Jamil, K.; Zakaullah, M.; Abu-Jarad, F.; Mujahid, S.A.

    2003-01-01

    There are several methods of measuring radon concentrations but nuclear track detector cylindrical dosimeters are widely employed. In this investigation, the consequence of effective volumes of the dosimeters on the registration of alpha tracks in a CR-39 detector was studied. In a series of experiments an optimum radius for a CR-39-based open cylindrical radon dosimeter was found to be about 3 cm. Monte Carlo simulation techniques hav been employed to verify the experimental results. In this context, a computer code Monte Carlo simulation dosimetry (MOCSID) was developed. Monte Carlo simulation experiments gave the optimum radius of the dosimeters as 3.0 cm. The experimental results are in good agreement with those obtained by Monte Carlo design calculations. In addition to this, plate-out effects of radon progeny were also studied. It was observed that the contribution of radon progeny ( 218 Po and 214 Po) plated-out on the wall of the dosimeters increases with an increase of dosimeter radii and then decrease to 0 at a radius of about 3 cm if a point detector has been installed at the center of the dosimeter base. In the code MOCSID different types of random number generators were employed. The results of this research are very useful for designing an optimum size of radon dosimeters

  16. A new dyed ECE track identification method for nuclear particle detection

    International Nuclear Information System (INIS)

    Sohrabi, M.; Bojd, S.S.

    1990-01-01

    A new procedure for obtaining highly contrasted red-dyed electrochemically etched recoil tracks in polymers such as polycarbonate (PC) and CR-39 has been successfully developed for spectrophotometry as applied to neutron dosimetry. The principal rationale in this method has been the provision of highly contrasted, photon-absorbing, large, dyed recoil tracks in an unaffected bulk material. The method consists of: (a) exposing the polymer to charged particles or neutrons; (b) electrochemical etching of the tracks; (c) acid sensitization; (d) dyeing with an appropriate dye. By investigation of the type, concentration, duration and temperature of the acid and the dye, optimized values of 20% by weight acrylic acid at 75 0 C for 3.5 h for sensitization, and 3% by weight eosin bluish dye at 95 0 C for 4 h for dyeing, provided a nearly 100% dyed-track efficiency. Spectrophotometry by UV and infrared radiation track counting, and optical densitometry were applied to the dyed samples. The results have shown some promise for UV absorbance measurements in routine large-scale applications. In this paper, the results of optimization studies and preliminary application of the technique to neutron dosimetry are presented and discussed. (author)

  17. Use of Image Pro Plus for counting of α particles tracks in CR-39

    International Nuclear Information System (INIS)

    Miranda, Marcia Valeria F.E. Sa; Crispim, Verginia Reis

    2011-01-01

    This paper measured the radon radiations present in NORM samples, through the diffusion chambers which contained a nuclear track detector (CR-39). For automatic counting of those tracks the computer program Image Pro plus was used. This paper reports the application of Image Pro plus for counting the nuclear tracks, coming from the radon radiation present in NORM samples. As the radiation rate of 222 Rn if proportional to the number of these tracks, the methodology allowed to compare the levels of contamination of the analysed samples. Also, tables and graphics are presented with counting results referring to the stage of validation of Image Pro plus

  18. Binder-free carbon nanotube electrode for electrochemical removal of chromium.

    Science.gov (United States)

    Wang, Haitao; Na, Chongzheng

    2014-11-26

    Electrochemical treatment of chromium-containing wastewater has the advantage of simultaneously reducing hexavalent chromium (CrVI) and reversibly adsorbing the trivalent product (CrIII), thereby minimizing the generation of waste for disposal and providing an opportunity for resource reuse. The application of electrochemical treatment of chromium is often limited by the available electrochemical surface area (ESA) of conventional electrodes with flat surfaces. Here, we report the preparation and evaluation of carbon nanotube (CNT) electrodes consisting of vertically aligned CNT arrays directly grown on stainless steel mesh (SSM). We show that the 3-D organization of CNT arrays increases ESA up to 13 times compared to SSM. The increase of ESA is correlated with the length of CNTs, consistent with a mechanism of roughness-induced ESA enhancement. The increase of ESA directly benefits CrVI reduction by proportionally accelerating reduction without compromising the electrode's ability to adsorb CrIII. Our results suggest that the rational design of electrodes with hierarchical structures represents a feasible approach to improve the performance of electrochemical treatment of contaminated water.

  19. Electrochemical reduction of nickel ions from dilute solutions

    NARCIS (Netherlands)

    Njau, K.N.; Janssen, L.J.J.

    1995-01-01

    Electrochemical reduction of nickel ions in dilute solution using a divided GBC-cell is of interest for purification of waste waters. A typical solution to be treated is the effluent from steel etching processes which contain low quantities of nickel, chromate and chromium ions. Reduction of

  20. Introducing etch kernels for efficient pattern sampling and etch bias prediction

    Science.gov (United States)

    Weisbuch, François; Lutich, Andrey; Schatz, Jirka

    2018-01-01

    Successful patterning requires good control of the photolithography and etch processes. While compact litho models, mainly based on rigorous physics, can predict very well the contours printed in photoresist, pure empirical etch models are less accurate and more unstable. Compact etch models are based on geometrical kernels to compute the litho-etch biases that measure the distance between litho and etch contours. The definition of the kernels, as well as the choice of calibration patterns, is critical to get a robust etch model. This work proposes to define a set of independent and anisotropic etch kernels-"internal, external, curvature, Gaussian, z_profile"-designed to represent the finest details of the resist geometry to characterize precisely the etch bias at any point along a resist contour. By evaluating the etch kernels on various structures, it is possible to map their etch signatures in a multidimensional space and analyze them to find an optimal sampling of structures. The etch kernels evaluated on these structures were combined with experimental etch bias derived from scanning electron microscope contours to train artificial neural networks to predict etch bias. The method applied to contact and line/space layers shows an improvement in etch model prediction accuracy over standard etch model. This work emphasizes the importance of the etch kernel definition to characterize and predict complex etch effects.

  1. Electrochemical Design of Optical Nanoantennas

    Directory of Open Access Journals (Sweden)

    Vasilchenko V.E.

    2015-01-01

    Full Text Available Electrochemical techniques for fabricating tapered gold nanoantennas (tips are discussed. In the paper, the tunable design of nanoantennas is demonstrated. Tip parameters such as a tip apex curvature, mesoscopic morphology, aspect ratio and enhancement factor can be varied with etching electrolyte and applied voltage. The low-cost method makes tipehnahced optical spectroscopy and microscopy feasible for routine optical measurements beyond the diffraction limit.

  2. KOH etched graphite felt with improved wettability and activity for vanadium flow batteries

    International Nuclear Information System (INIS)

    Zhang, Zhengyang; Xi, Jingyu; Zhou, Haipeng; Qiu, Xinping

    2016-01-01

    Highlights: • GF electrode is activated by KOH etching method for VFB application. • The wettability and activity of eGF electrode towards VO 2+ /VO 2 + and V 2+ /V 3+ couples are improved. • VFB with eGF electrode can run stable at current densities range from 50 to 250 mA cm −2 . • Cycling test at current density of 150 mA cm −2 confirms the superior durability of eGF electrode. - Abstract: In this work, a simple and effective method to activate graphite felt (GF) electrode by using KOH as etching agent is studied for vanadium flow battery (VFB) application. The surface of GF is etched by KOH at 800 °C to generate micropores and attain oxygen-containing functional groups, resulting in greatly improved electrolyte accessibility. Surface morphology, oxygen distribution and microstructure of the KOH etched graphite felts (eGFs) are characterized by SEM, EDX, XPS, XRD and Raman techniques. Due to the abundant exposed edge carbon sites and oxygen-containing functional groups introduced by KOH activation, electrochemical activity of eGFs towards both VO 2+ /VO 2 + and V 2+ /V 3+ redox couples are remarkably improved comparing with GF. In particular, eGF-2 (mass ratio of KOH/GF = 1.25) exhibits the best electrochemical activity and VFB performance among all eGFs. Moreover, the VFB with eGF-2 electrode can run at current density up to 250 mA cm −2 with the energy efficiency of 64%. Long-term cycle life test at higher current density of 150 mA cm −2 confirms the outstanding stability of eGF-2 electrode.

  3. Planarization of the diamond film surface by using the hydrogen plasma etching with carbon diffusion process

    International Nuclear Information System (INIS)

    Kim, Sung Hoon

    2001-01-01

    Planarization of the free-standing diamond film surface as smooth as possible could be obtained by using the hydrogen plasma etching with the diffusion of the carbon species into the metal alloy (Fe, Cr, Ni). For this process, we placed the free-standing diamond film between the metal alloy and the Mo substrate like a metal-diamond-molybdenum (MDM) sandwich. We set the sandwich-type MDM in a microwave-plasma-enhanced chemical vapor deposition (MPECVD) system. The sandwich-type MDM was heated over ca. 1000 .deg. C by using the hydrogen plasma. We call this process as the hydrogen plasma etching with carbon diffusion process. After etching the free-standing diamond film surface, we investigated surface roughness, morphologies, and the incorporated impurities on the etched diamond film surface. Finally, we suggest that the hydrogen plasma etching with carbon diffusion process is an adequate etching technique for the fabrication of the diamond film surface applicable to electronic devices

  4. Activation behaviour of ZrCrNi mechanically milled with nickel

    International Nuclear Information System (INIS)

    Jung, C. B.; Ho Kim, J.; Sub Lee, K.

    1998-01-01

    AB 2 type Laves phase alloys have some promising properties as a negative electrode in rechargeable Ni/MH batteries because of high electrochemical capacity and good cyclic life. However, they have the disadvantage of requiring many charge-discharge cycles for activation. In this study, the mechanical milling with nickel has been introduced to modify the electrochemical behaviour of the ZrCrNi alloy. A composite-like structure (ZrCrNi+nickel) and nanocrystalline ZrCrNi were obtained through the mechanical milling and the hydrogenation behaviour of the electrode was greatly improved. (orig.)

  5. Track-etch dosemeter response to neutrons up to 300 MeV

    International Nuclear Information System (INIS)

    Devine, R.T.; Walker, S.; Staples, P.; Duran, M.; Mundis, R.; Miller, J.

    1996-01-01

    Electro-chemical and chemical track-etch dosemeters were obtained from commercial suppliers and exposed to neutrons produced at the LANTF WNR white neutron source at 15 degree with no shielding and filtered by polyethylene blocks of 2.5, 5.1, 10.2, 20.3 and 40.6 cin thickness. The neutron spectrum was determined using calculations. Mean energies from 28 to 300 MeV were produced. Dose was calculated from the NCRP-38 flux-to-dose conversion. The results are compared with NTA film which was exposed in the same configuration. The response of track etch dosimeters was found to reach a minimum and then rise as the average neutron energy increased. The response of the NTA film increased as the neutron energy increased

  6. Self-etch and etch-and-rinse adhesive systems in clinical dentistry.

    Science.gov (United States)

    Ozer, Fusun; Blatz, Markus B

    2013-01-01

    Current adhesive systems follow either an "etch-and-rinse" or "self-etch" approach, which differ in how they interact with natural tooth structures. Etch-and-rinse systems comprise phosphoric acid to pretreat the dental hard tissues before rinsing and subsequent application of an adhesive. Self-etch adhesives contain acidic monomers, which etch and prime the tooth simultaneously. Etch-and-rinse adhesives are offered as two- or three-step systems, depending on whether primer and bonding are separate or combined in a single bottle. Similarly, self-etch adhesives are available as one- or two-step systems. Both etch-and-rinse and self-etch systems form a hybrid layer as a result of resins impregnating the porous enamel or dentin. Despite current trends toward fewer and simpler clinical application steps, one-step dentin bonding systems exhibit bonding agent lower bond strengths and seem less predictable than multi-step etch-and-rinse and self-etch systems. The varying evidence available today suggests that the choice between etch-and-rinse and self-etch systems is often a matter of personal preference. In general, however, phosphoric acid creates a more pronounced and retentive etching pattern in enamel. Therefore, etch-and-rinse bonding systems are often preferred for indirect restorations and when large areas of enamel are still present. Conversely, self-etch adhesives provide superior and more predictable bond strength to dentin and are, consequently, recommended for direct composite resin restorations, especially when predominantly supported by dentin.

  7. Chemically Etched Silicon Nanowires as Anodes for Lithium-Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    West, Hannah Elise [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    This study focused on silicon as a high capacity replacement anode for Lithium-ion batteries. The challenge of silicon is that it expands ~270% upon lithium insertion which causes particles of silicon to fracture, causing the capacity to fade rapidly. To account for this expansion chemically etched silicon nanowires from the University of Maine were studied as anodes. They were built into electrochemical half-cells and cycled continuously to measure the capacity and capacity fade.

  8. Determining of the track parameters in solid state nuclear track detectors Cr 39 due to alpha particles

    International Nuclear Information System (INIS)

    Kostic, D.; Nikezic, D.

    1997-01-01

    An equation of the etch pit wall is proposed to be used for simulation of the track growth and calculating the major and the minor axis of etch pit opening. Dependence on the following parameters is set up: distance along a track from the point where the particle entered the detector, ratio of the track etch wall to the bulk etch rate, integration constant determined from particle penetration depth and normal distance from the particle trajectory to the etch pit wall. The corresponding computer program was written. The input parameters of this program are: alpha particles energy, incidence angle and removed layer; the output gives track parameters. The results obtained by this method are compared to another approach given by Somogy and Szalay (1973) and a reasonably good agreement is found. (author)

  9. The study of optimal conditions of electrochemical etching of tunnel electron microscopy tungsten tips; Estudio de las condiciones optimas para la preparacion electroquimica de puntas de tungsteno para el Microscopio de Efecto Tunel

    Energy Technology Data Exchange (ETDEWEB)

    Anguiano, E; Aguilar, M [Instituto de Ciencia de Materiales del SCIC, Madrid (Spain); Olivar, A I [Centro de Investigacion y de Estudios Avanzados del IPN Unidad Merida. Departamento de fisica Aplicada, Yucatan, Mexico (Mexico)

    1997-12-31

    We present the experimental results obtained during the study made in the electrochemical etching of tunneling electron microscopy tungsten tips. The experiments was made using DC and two usual electrolytes: KOH and NaOH. For the tip preparation we used a electrochemical cell with stainless steel cathode and the tungsten wire as anode. the electrodes was introduced in a glass recipient containing the electrolytic solution. We study the effects of applied voltage, polish time, tip length and electrolyte concentration as process relevant parameters. The best condition for tip preparation was obtained with a metallurgical microscope and with a SEM.EDX and Auger analysis was made. The results shown the better tips was made with KOH as electrolyte with a limited concentration range (2-4 normal) and applied voltage (2-6 volts) (Author) 20 refs.

  10. Preliminary results of fission induced by (1068 MeV) pi in Cu, Sn, Au and Bi using CR-39 detectors

    CERN Document Server

    Khan, H A; Shahzad, M I; Manzoor, S; Farooq, M A; Sher, G; Khan, E U; Peterson, R J

    1999-01-01

    Fission probabilities in pion induced reactions exhibit characteristic variations with respect to pion energies and target fissility values. At incident energies well above the pion-nucleon resonances, the statistical model seems to give good description of the observed data. We have used negative pions of energy 1068 MeV, in order to study fission induced in four target materials with fissility values [(Z-1)2/A] ranging from 12 to 32. All targets were arranged in a single stack in such a way that each target coated on a CR-39 detector was sandwiched by another uncoated CR-39 detector plate. The stack was irradiated at the AGS of Brookhaven National Laboratory (USA). This set-up ensures solid angle coverage of almost 4 pi degrees, so that for each fission event one of the fission fragments is expected to be trapped by the forward detector and one by the detector covering backward hemisphere. The effect of pion momentum transfer to the struck nucleus was observed in the form of asymmetry between events counted...

  11. Characterization of mechanical properties and electrochemical behaviour in a Hank´s solution of 316L/Cr1-xAlxN system

    International Nuclear Information System (INIS)

    Osorio, D M; Caicedo, J C; Zambrano, G; Aperador, W; Benitez-Castro, A M; Giraldo-Betancur, A L; Muñoz-Saldaña, J; Yañez-Limón, J M; Sanchez, O

    2017-01-01

    Cr 1-x Al x N hard coatings were successfully deposited by R.F. reactive magnetron co-sputtering in an Ar/N2 gas mixture using chromium and aluminium targets on 316L stainless steel substrates. Crystallographic orientations associated to the Cr 1-x Al x N FCC based in the conjugate complex of CrN and w-AlN phases, with ao=4.18Å lattice parameter for the ternary Cr 1-x Al x N compound were identified by X-Ray diffraction. The thickness and roughness of the deposited coatings are 1.00±0.05nm and 2.65±0.6nm, respectively. The mechanical properties were determined by nanoindentation leading to a hardness of 27.8±2.6GPa and elastic modulus of 346GPa. The corrosion resistance of the coated 316L/Cr 1-x Al x N system under simulated body fluid (SBF, Hank’s solution) was determined via electrochemical impedance spectroscopy. A reduction in the corrosion rate of 99% in relation to uncoated 316L stainless steel substrate was found by Tafel. Thus, these coatings seem to be excellent candidates to be used in biomedical applications. (paper)

  12. Measurement of concentrations of radon and its daughters in indoor atmosphere using CR-39 nuclear track detector

    International Nuclear Information System (INIS)

    Khan, A.J.; Sharma, K.C.; Varshney, A.K.; Prasad, Rajendra; Tyagi, R.K.

    1988-01-01

    The concentrations of radon and its daughters in rooms having different environmental conditions are measured using CR-39 nuclear track detector. It has been found that the radon concentration inside the rooms depends on ventilation, sub-soil emanation and the housed materials. The use of internal wall coverings such as plaster, distemper and white washing may reduce the radon emanation inside the rooms. The use of paints on walls is the best for reducing the radon concentration inside the rooms. (author). 11 refs

  13. An automatic analyzer of solid state nuclear track detectors using an optic RAM as image sensor

    International Nuclear Information System (INIS)

    Staderini, E.M.; Castellano, A.

    1986-01-01

    An optic RAM is a conventional digital random access read/write dynamic memory device featuring a quartz windowed package and memory cells regularly ordered on the chip. Such a device is used as an image sensor because each cell retains data stored in it for a time depending on the intensity of the light incident on the cell itself. The authors have developed a system which uses an optic RAM to acquire and digitize images from electrochemically etched CR39 solid state nuclear track detectors (SSNTD) in the track count rate up to 5000 cm -2 . On the digital image so obtained, a microprocessor, with appropriate software, performs image analysis, filtering, tracks counting and evaluation. (orig.)

  14. Improved Bi Film Wrapped Single Walled Carbon Nanotubes for Ultrasensitive Electrochemical Detection of Trace Cr(VI)

    Science.gov (United States)

    Zhou, Shilin; Xue, Zi-Ling; Xu, Lina; Gu, Yingying; Miao, Yuqing

    2014-01-01

    We report here the successful fabrication of an improved Bi film wrapped single walled carbon nanotubes modified glassy carbon electrode (Bi/SWNTs/GCE) as a highly sensitive platform for ultratrace Cr(VI) detection through catalytic adsorptive cathodic stripping voltammetry (AdCSV). The introduction of negatively charged SWNTs extraordinarily decreased the size of Bi particles to nanoscale due to electrostatic interaction which made Bi(III) cations easily attracted onto the surface of SWNTs in good order, leading to higher quality of Bi film deposition. The obtained Bi/SWNTs composite was well characterized with electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), the static water contact angle and the voltammetric measurements. The results demonstrates the improvements in the quality of Bi film deposited on the surface of SWNTs such as faster speed of electron transfer, more uniform and smoother morphology, better hydrophilicity and higher stripping signal. Using diethylene triaminepentaacetic acid (DTPA) as complexing ligand, the fabricated electrode displays a well-defined and highly sensitive peak for the reduction of Cr(III)-DTPA complex at −1.06 V (vs. Ag/AgCl) with a linear concentration range of 0–25 nM and a fairly low detection limit of 0.036 nM. No interference was found in the presence of coexisting ions, and good recoveries were achieved for the analysis of a river sample. In comparison to previous approaches using Bi film modified GCE, the newly designed electrode exhibits better reproducibility and repeatability towards aqueous detection of trace Cr(VI) and appears to be very promising as the basis of a highly sensitive and selective voltammetric procedure for Cr(VI) detection at trace level in real samples. PMID:24771881

  15. Effects of lipopolysaccharides on the corrosion behavior of Ni-Cr and Co-Cr alloys.

    Science.gov (United States)

    Yu, Weiqiang; Qian, Chao; Weng, Weimin; Zhang, Songmei

    2016-08-01

    Lipopolysaccharides (LPS) are constituents of gingival crevicular fluid and may affect the base metal alloys used in metal ceramic crowns. The role of LPS in base metal alloys is currently unknown. The purpose of this in vitro study was to evaluate the effects of gram-negative bacterial LPS on the electrochemical behavior of Ni-Cr and Co-Cr alloys. Alloy specimens were divided into 4 groups according to Escherichia coli LPS concentration (0, 0.15, 15, and 150 μg/mL) in acidic saliva (pH 5). Open circuit potential (OCP) and potentiodynamic polarization behavior were examined using a computer-controlled potentiostat. Metal ions released from the 2 alloys were measured by immersion in LPS-free solution and 150 μg/mL LPS solution and analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). Data were evaluated using 1-way ANOVA (α=.05). Compared with control groups, medium LPS concentration (15 μg/mL) accelerated Ni-Cr alloy corrosion (Palloy corrosion (Pcorrosion current density, and polarization resistance parameters. After immersion in high LPS concentrations (150 μg/mL), a slight increase in Ni ion release (P >.05) was observed for the Ni-Cr alloy, while a more significant Co ion release (Palloy. LPS negatively affected the electrochemical behavior of both the Ni-Cr and Co-Cr alloys. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  16. Electrical, structural, and bonding changes induced in silicon by H, Ar, and Kr ion-beam etching

    International Nuclear Information System (INIS)

    Singh, R.; Fonash, S.J.; Ashok, S.; Caplan, P.; Shappirio, J.; Hage-Ali, M.; Ponpon, J.

    1983-01-01

    A study to elucidate the role of processing-induced changes in Si, subjected to ion-beam etching has been made. It is shown that these changes can be related to the primary ion beam used in ion-beam etching. Using ESR, trivalently bonded Si has been shown to be present. Fe and Cr have been found to be the main contaminants. An annealing study revealed that the damage can be annealed out at relatively high temperatures

  17. Etch bias inversion during EUV mask ARC etch

    Science.gov (United States)

    Lajn, Alexander; Rolff, Haiko; Wistrom, Richard

    2017-07-01

    The introduction of EUV lithography to high volume manufacturing is now within reach for 7nm technology node and beyond (1), at least for some steps. The scheduling is in transition from long to mid-term. Thus, all contributors need to focus their efforts on the production requirements. For the photo mask industry, these requirements include the control of defectivity, CD performance and lifetime of their masks. The mask CD performance including CD uniformity, CD targeting, and CD linearity/ resolution, is predominantly determined by the photo resist performance and by the litho and etch processes. State-of-the-art chemically amplified resists exhibit an asymmetric resolution for directly and indirectly written features, which usually results in a similarly asymmetric resolution performance on the mask. This resolution gap may reach as high as multiple tens of nanometers on the mask level in dependence of the chosen processes. Depending on the printing requirements of the wafer process, a reduction or even an increase of this gap may be required. A potential way of tuning via the etch process, is to control the lateral CD contribution during etch. Aside from process tuning knobs like pressure, RF powers and gases, which usually also affect CD linearity and CD uniformity, the simplest knob is the etch time itself. An increased over etch time results in an increased CD contribution in the normal case. , We found that the etch CD contribution of ARC layer etch on EUV photo masks is reduced by longer over etch times. Moreover, this effect can be demonstrated to be present for different etch chambers and photo resists.

  18. Buffered Electrochemical Polishing of Niobium

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Tian, Hui [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); College of William and Mary, Williamsburg, VA (United States); Corcoran, Sean [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    2011-03-01

    The standard preparation of superconducting radio-frequency (SRF) cavities made of pure niobium include the removal of a 'damaged' surface layer, by buffered chemical polishing (BCP) or electropolishing (EP), after the cavities are formed. The performance of the cavities is characterized by a sharp degradation of the quality factor when the surface magnetic field exceeds about 90 mT, a phenomenon referred to as 'Q-drop.' In cavities made of polycrystalline fine grain (ASTM 5) niobium, the Q-drop can be significantly reduced by a low-temperature (? 120 °C) 'in-situ' baking of the cavity if the chemical treatment was EP rather than BCP. As part of the effort to understand this phenomenon, we investigated the effect of introducing a polarization potential during buffered chemical polishing, creating a process which is between the standard BCP and EP. While preliminary results on the application of this process to Nb cavities have been previously reported, in this contribution we focus on the characterization of this novel electrochemical process by measuring polarization curves, etching rates, surface finish, electrochemical impedance and the effects of temperature and electrolyte composition. In particular, it is shown that the anodic potential of Nb during BCP reduces the etching rate and improves the surface finish.

  19. Multiwall carbon nanotubes decorated with FeCr{sub 2}O{sub 4}, a new selective electrochemical sensor for amoxicillin determination

    Energy Technology Data Exchange (ETDEWEB)

    Ensafi, Ali Asghar, E-mail: Ensafi@cc.iut.ac.ir; Allafchian, Ali Reza; Rezaei, Behzad [Isfahan University of Technology, Department of Chemistry (Iran, Islamic Republic of)

    2012-11-15

    FeCr{sub 2}O{sub 4} nanoparticles were synthesized and then multiwall carbon nanotubes (MWCNTs) were decorated with FeCr{sub 2}O{sub 4} nanoparticles. The new nanoparticles were characterized with different techniques such as vibrating sample magnetometer, Fourier transform infrared spectroscopy, scanning surface microscopy, transmission electron microscopy (TEM), atomic force microscopy (AFM), and electrochemical impedance spectroscopy. The results of the study confirm that the particles are pure FeCr{sub 2}O{sub 4}-MWCNTs with a cubic structure. No diffraction peaks of other impurities such as FeO or Cr{sub 2}O{sub 3} were observed. The diffractive peaks of FeCr{sub 2}O{sub 4}-MWCNTs are broadened, implying that the crystalline size of FeCr{sub 2}O{sub 4}-MWCNTs particles is quite small. The mean particle size of FeCr{sub 2}O{sub 4}-MWCNTs calculated by Scherrer equation is about 25 nm, whereas the existence of particles with less than 30 nm size at FeCr{sub 2}O{sub 4}-MWCNTs is clearly reflected in 2D and 3D AFM images. The TEM image confirms that the spaghetti-like FeCr{sub 2}O{sub 4}-MWCNTs formed a porous structure. The synthesized FeCr{sub 2}O{sub 4}-MWCNTs nanoparticles could be used as a new electrocatalysis for voltammetric determination of amoxicillin (AMC). Under the optimized conditions at pH 7.5 and in differential pulse voltammetry, the oxidation peak current of AMC at the surface of the mediator has two linear dynamic ranges including 0.1-10.0 and 10.0-70.0 {mu}mol L{sup -1}. The detection limit of 0.05 {mu}mol L{sup -1} was achieved. The influence of potential interfering compounds on the selectivity was studied. Finally, the modified electrode showed good sensitivity, selectivity, and stability for the determination of AMC in real samples.

  20. Improved Bi film wrapped single walled carbon nanotubes for ultrasensitive electrochemical detection of trace Cr(VI)

    International Nuclear Information System (INIS)

    Ouyang, Ruizhuo; Zhang, Wangyao; Zhou, Shilin; Xue, Zi-Ling; Xu, Lina; Gu, Yingying; Miao, Yuqing

    2013-01-01

    Highlights: • Electrostatic interaction improves the quality of Bi deposition. • The designed Bi/SWNTs/GCE shows many advantages over Bi/GCE toward Cr VI detection. • The Bi/SWNTs/GCE exhibits good analyzing behavior with pretty low detection limit. • The fabricated sensor is better of reproducibility, repeatability and life time. • River samples were successfully analyzed using current sensor for Cr VI detection. -- Abstract: We report here the successful fabrication of an improved Bi film wrapped single walled carbon nanotubes modified glassy carbon electrode (Bi/SWNTs/GCE) as a highly sensitive platform for ultratrace Cr(VI) detection through catalytic adsorptive cathodic stripping voltammetry (AdCSV). The introduction of negatively charged SWNTs extraordinarily decreased the size of Bi particles to nanoscale due to electrostatic interaction which made Bi(III) cations easily attracted onto the surface of SWNTs in good order, leading to higher quality of Bi film deposition. The obtained Bi/SWNTs composite was well characterized with electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), the static water contact angle and the voltammetric measurements. The results demonstrate the improvements in the quality of Bi film deposited on the surface of SWNTs such as faster speed of electron transfer, more uniform and smoother morphology, better hydrophilicity and higher stripping signal. Using diethylene triaminepentaacetic acid (DTPA) as complexing ligand, the fabricated electrode displays a well-defined and highly sensitive peak for the reduction of Cr(III)–DTPA complex at −1.06 V (vs. Ag/AgCl) with a linear concentration range of 0–25 nM and a fairly low detection limit of 0.036 nM. No interference was found in the presence of coexisting ions, and good recoveries were achieved for the analysis of a river sample. In comparison to previous approaches using Bi film modified GCE, the newly designed electrode exhibits better

  1. Anodic etching of GaN based film with a strong phase-separated InGaN/GaN layer: Mechanism and properties

    International Nuclear Information System (INIS)

    Gao, Qingxue; Liu, Rong; Xiao, Hongdi; Cao, Dezhong; Liu, Jianqiang; Ma, Jin

    2016-01-01

    Highlights: • GaN film with a strong phase-separated InGaN/GaN layer was etched by electrochemical etching. • Vertically aligned nanopores in n-GaN films were buried underneath the InGaN/GaN structures. • The relaxation of compressive stress in the MQW structure was found by PL and Raman spectra. - Abstract: A strong phase-separated InGaN/GaN layer, which consists of multiple quantum wells (MQW) and superlattices (SL) layers and can produce a blue wavelength spectrum, has been grown on n-GaN thin film, and then fabricated into nanoporous structures by electrochemical etching method in oxalic acid. Scanning electron microscopy (SEM) technique reveals that the etching voltage of 8 V leads to a vertically aligned nanoporous structure, whereas the films etched at 15 V show branching pores within the n-GaN layer. Due to the low doping concentration of barriers (GaN layers) in the InGaN/GaN layer, we observed a record-low rate of etching (<100 nm/min) and nanopores which are mainly originated from the V-pits in the phase-separated layer. In addition, there exists a horizontal nanoporous structure at the interface between the phase-separated layer and the n-GaN layer, presumably resulting from the high transition of electrons between the barrier and the well (InGaN layer) at the interface. As compared to the as-grown MQW structure, the etched MQW structure exhibits a photoluminescence (PL) enhancement with a partial relaxation of compressive stress due to the increased light-extracting surface area and light-guiding effect. Such a compressive stress relaxation can be further confirmed by Raman spectra.

  2. Anodic etching of GaN based film with a strong phase-separated InGaN/GaN layer: Mechanism and properties

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Qingxue [School of Physics, Shandong University, Jinan, 250100 (China); Liu, Rong [Department of Fundamental Theories, Shandong Institute of Physical Education and Sports, Jinan 250063 (China); Xiao, Hongdi, E-mail: hdxiao@sdu.edu.cn [School of Physics, Shandong University, Jinan, 250100 (China); Cao, Dezhong; Liu, Jianqiang; Ma, Jin [School of Physics, Shandong University, Jinan, 250100 (China)

    2016-11-30

    Highlights: • GaN film with a strong phase-separated InGaN/GaN layer was etched by electrochemical etching. • Vertically aligned nanopores in n-GaN films were buried underneath the InGaN/GaN structures. • The relaxation of compressive stress in the MQW structure was found by PL and Raman spectra. - Abstract: A strong phase-separated InGaN/GaN layer, which consists of multiple quantum wells (MQW) and superlattices (SL) layers and can produce a blue wavelength spectrum, has been grown on n-GaN thin film, and then fabricated into nanoporous structures by electrochemical etching method in oxalic acid. Scanning electron microscopy (SEM) technique reveals that the etching voltage of 8 V leads to a vertically aligned nanoporous structure, whereas the films etched at 15 V show branching pores within the n-GaN layer. Due to the low doping concentration of barriers (GaN layers) in the InGaN/GaN layer, we observed a record-low rate of etching (<100 nm/min) and nanopores which are mainly originated from the V-pits in the phase-separated layer. In addition, there exists a horizontal nanoporous structure at the interface between the phase-separated layer and the n-GaN layer, presumably resulting from the high transition of electrons between the barrier and the well (InGaN layer) at the interface. As compared to the as-grown MQW structure, the etched MQW structure exhibits a photoluminescence (PL) enhancement with a partial relaxation of compressive stress due to the increased light-extracting surface area and light-guiding effect. Such a compressive stress relaxation can be further confirmed by Raman spectra.

  3. Surface engineered porous silicon for stable, high performance electrochemical supercapacitors

    Science.gov (United States)

    Oakes, Landon; Westover, Andrew; Mares, Jeremy W.; Chatterjee, Shahana; Erwin, William R.; Bardhan, Rizia; Weiss, Sharon M.; Pint, Cary L.

    2013-10-01

    Silicon materials remain unused for supercapacitors due to extreme reactivity of silicon with electrolytes. However, doped silicon materials boast a low mass density, excellent conductivity, a controllably etched nanoporous structure, and combined earth abundance and technological presence appealing to diverse energy storage frameworks. Here, we demonstrate a universal route to transform porous silicon (P-Si) into stable electrodes for electrochemical devices through growth of an ultra-thin, conformal graphene coating on the P-Si surface. This graphene coating simultaneously passivates surface charge traps and provides an ideal electrode-electrolyte electrochemical interface. This leads to 10-40X improvement in energy density, and a 2X wider electrochemical window compared to identically-structured unpassivated P-Si. This work demonstrates a technique generalizable to mesoporous and nanoporous materials that decouples the engineering of electrode structure and electrochemical surface stability to engineer performance in electrochemical environments. Specifically, we demonstrate P-Si as a promising new platform for grid-scale and integrated electrochemical energy storage.

  4. Surface engineered porous silicon for stable, high performance electrochemical supercapacitors

    Science.gov (United States)

    Oakes, Landon; Westover, Andrew; Mares, Jeremy W.; Chatterjee, Shahana; Erwin, William R.; Bardhan, Rizia; Weiss, Sharon M.; Pint, Cary L.

    2013-01-01

    Silicon materials remain unused for supercapacitors due to extreme reactivity of silicon with electrolytes. However, doped silicon materials boast a low mass density, excellent conductivity, a controllably etched nanoporous structure, and combined earth abundance and technological presence appealing to diverse energy storage frameworks. Here, we demonstrate a universal route to transform porous silicon (P-Si) into stable electrodes for electrochemical devices through growth of an ultra-thin, conformal graphene coating on the P-Si surface. This graphene coating simultaneously passivates surface charge traps and provides an ideal electrode-electrolyte electrochemical interface. This leads to 10–40X improvement in energy density, and a 2X wider electrochemical window compared to identically-structured unpassivated P-Si. This work demonstrates a technique generalizable to mesoporous and nanoporous materials that decouples the engineering of electrode structure and electrochemical surface stability to engineer performance in electrochemical environments. Specifically, we demonstrate P-Si as a promising new platform for grid-scale and integrated electrochemical energy storage. PMID:24145684

  5. Interaction of 80 MeV PI+ with different targets: Track detector studies

    Energy Technology Data Exchange (ETDEWEB)

    Tabassum, L; Chohan, A S [Government Coll., Lahore. (Pakistan) Deptt. of Physics Khan, H.A. (Pakistan Inst. of Nuclear Science and Technology, Islamabad (Pakistan). Nuclear Engineering Div.)

    1990-04-01

    CR-39 and mica track detectors have been used in the study of the interactions of 80 MeV PI+ with thin targets of Bi, Pb, Ho, Sb. The binary fission cross sections, the length and angular distributions of etched tracks have been obtained. The cross-section values obtained by using CR-39 are higher as compared to those obtained with mica. (author).

  6. Interaction of 80 MeV PI+ with different targets: Track detector studies

    International Nuclear Information System (INIS)

    Tabassum, L.; Chohan, A.S.

    1990-01-01

    CR-39 and mica track detectors have been used in the study of the interactions of 80 MeV PI+ with thin targets of Bi, Pb, Ho, Sb. The binary fission cross sections, the length and angular distributions of etched tracks have been obtained. The cross-section values obtained by using CR-39 are higher as compared to those obtained with mica. (author)

  7. In-situ electrochemical-AFM study of localized corrosion of AlxCoCrFeNi high-entropy alloys in chloride solution

    Science.gov (United States)

    Shi, Yunzhu; Collins, Liam; Balke, Nina; Liaw, Peter K.; Yang, Bin

    2018-05-01

    In-situ electrochemical (EC)-AFM is employed to investigate the localized corrosion of the AlxCoCrFeNi high-entropy alloys (HEAs). Surface topography changes on the micro/sub-micro scale are monitored at different applied anodizing potentials in a 3.5 wt% NaCl solution. The microstructural evolutions with the increased Al content in the alloys are characterized by SEM, TEM, EDS and EBSD. The results show that by increasing the Al content, the microstructure changes from single solid-solution to multi-phases, leading to the segregations of elements. Due to the microstructural variations in the AlxCoCrFeNi HEAs, localized corrosion processes in different ways after the breakdown of the passive film, which changes from pitting to phase boundary corrosion. The XPS results indicate that an increased Al content in the alloys/phases corresponds to a decreased corrosion resistance of the surface passive film.

  8. Characterization of electrochemical and passive behaviour of Alloy 59 in acid solution

    International Nuclear Information System (INIS)

    Luo, Hong; Gao, Shujun; Dong, Chaofang; Li, Xiaogang

    2014-01-01

    Highlights: • A considerably thinner n-type passive film is observed on the Alloy-59. • The passive film formed in air was thicker than that formed in acid solution. • Primary constituents of passive film in air and acid solution are (Cr, Ni)-oxides and (Cr, Ni) hydroxides, respectively. - Abstract: The electrochemical behaviour and passive film properties of the Alloy 59 in sulfuric acid solution was evaluated by the potentiodynamic electrochemical measurements, electrochemical impedance spectroscopy, Mott-Schottky approach, and ex situ surface analytical technique as X-ray photoelectron spectroscopy (XPS) and Auger Electronic Spectrometer (AES). The results confirmed that the Alloy 59 exhibits well passive behaviour. A considerably thinner n-type passive film is observed on this type alloy. Based on the evaluations of surface composition analysis, the primary constituents of passive film formed in the air and acid solution are different, with the (Cr, Ni)-oxides and (Cr, Ni) hydroxides, respectively

  9. Effect of Molybdenum on the Corrosion Behavior of High-Entropy Alloys CoCrFeNi2 and CoCrFeNi2Mo0.25 under Sodium Chloride Aqueous Conditions

    Directory of Open Access Journals (Sweden)

    Alvaro A. Rodriguez

    2018-01-01

    Full Text Available The corrosion behavior of high-entropy alloys (HEAs CoCrFeNi2 and CoCrFeNi2Mo0.25 was investigated in 3.5 wt. percent sodium chloride (NaCl at 25°C by electrochemical methods. Their corrosion parameters were compared to those of HASTELLOY® C-276 (UNS N10276 and stainless steel 316L (UNS 31600 to assess the suitability of HEAs for potential industrial applications in NaCl simulating seawater type environments. The corrosion rates were calculated using corrosion current determined from electrochemical experiments for each of the alloys. In addition, potentiodynamic polarization measurements can indicate active, passive, and transpassive behavior of the metal as well as potential susceptibility to pitting corrosion. Cyclic voltammetry (CV can confirm the alloy susceptibility to pitting corrosion. Electrochemical impedance spectroscopy (EIS elucidates the corrosion mechanism under studied conditions. The results of the electrochemical experiments and scanning electron microscopy (SEM analyses of the corroded surfaces revealed general corrosion on alloy CoCrFeNi2Mo0.25 and HASTELLOY C-276 and pitting corrosion on alloy CoCrFeNi2 and stainless steel 316L.

  10. Calibration of thermal neutron detection compound BN-1 and CR-39 in the exposure room of Triga Reactor in Ljubljana

    International Nuclear Information System (INIS)

    Kristof, E.; Ilic, R.; Skvarc, J.; Dijanosic, R.

    1994-01-01

    Description of determination of thermal neutron fluences in the range from 1.E+02 to 1.E+12 cm -2 for calibration of the neutron sensitive compound consisting of the neutron converter BN-1 and charged particle detector CR-39 is given. The method employs two proportional BF3 detectors supplemented by a Ge(Li) gamma spectometer utilizing gold foils. The results of the measurements are also presented. (author)

  11. Experimental Monitoring of Cr(VI) Bio-reduction Using Electrochemical Geophysics

    International Nuclear Information System (INIS)

    Birsen Canan; Gary R. Olhoeft; William A. Smith

    2007-01-01

    Many Department of Energy (DOE) sites are contaminated with highly carcinogenic hexavalent chromium (Cr(VI)). In this research, we explore the feasibility of applying complex resistivity to the detection and monitoring of microbially-induced reduction of hexavalent chromium (Cr(VI)) to a less toxic form (Cr(III)). We hope to measure the change in ionic concentration that occurs during this reduction reaction. This form of reduction promises to be an attractive alternative to more expensive remedial treatment methods. The specific goal of this research is to define the minimum and maximum concentration of the chemical and biological compounds in contaminated samples for which the Cr(VI) - Cr(III) reduction processes could be detected via complex resistivity. There are three sets of experiments, each comprised of three sample columns. The first experiment compares three concentrations of Cr(VI) at the same bacterial cell concentration. The second experiment establishes background samples with, and without, Cr(VI) and bacterial cells. The third experiment examines the influence of three different bacterial cell counts on the same concentration of Cr(VI). A polarization relaxation mechanism was observed between 10 and 50 Hz. The polarization mechanism, unfortunately, was not unique to bio-chemically active samples. Spectral analysis of complex resistivity data, however, showed that the frequency where the phase minimum occurred was not constant for bio-chemically active samples throughout the experiment. A significant shifts in phase minima occurred between 10 to 20 Hz from the initiation to completion of Cr(VI) reduction. This phenomena was quantified using the Cole-Cole model and the Marquardt-Levenberg nonlinear least square minimization method. The data suggests that the relaxation time and the time constant of this relaxation are the Cole-Cole parameters most sensitive to changes in biologically-induced reduction of Cr(VI)

  12. Two-year Randomized Clinical Trial of Self-etching Adhesives and Selective Enamel Etching.

    Science.gov (United States)

    Pena, C E; Rodrigues, J A; Ely, C; Giannini, M; Reis, A F

    2016-01-01

    The aim of this randomized, controlled prospective clinical trial was to evaluate the clinical effectiveness of restoring noncarious cervical lesions with two self-etching adhesive systems applied with or without selective enamel etching. A one-step self-etching adhesive (Xeno V(+)) and a two-step self-etching system (Clearfil SE Bond) were used. The effectiveness of phosphoric acid selective etching of enamel margins was also evaluated. Fifty-six cavities were restored with each adhesive system and divided into two subgroups (n=28; etch and non-etch). All 112 cavities were restored with the nanohybrid composite Esthet.X HD. The clinical effectiveness of restorations was recorded in terms of retention, marginal integrity, marginal staining, caries recurrence, and postoperative sensitivity after 3, 6, 12, 18, and 24 months (modified United States Public Health Service). The Friedman test detected significant differences only after 18 months for marginal staining in the groups Clearfil SE non-etch (p=0.009) and Xeno V(+) etch (p=0.004). One restoration was lost during the trial (Xeno V(+) etch; p>0.05). Although an increase in marginal staining was recorded for groups Clearfil SE non-etch and Xeno V(+) etch, the clinical effectiveness of restorations was considered acceptable for the single-step and two-step self-etching systems with or without selective enamel etching in this 24-month clinical trial.

  13. Progress report, Health Sciences Division: 1982 July 1 - September 30

    International Nuclear Information System (INIS)

    1982-12-01

    Research at CRNL in health physics included characterization of electrochemically etched CR39 plastic, study of superheated liquid drops trapped in gels, measurement of HTO in background gamma fields, and development of components for a wide-range reactor stack effluent monitor. Environmental research continued with local hydrological studies, adsorption/desorption models of Co-60, studies of physical-chemical processes in sedimentation in lakes and rivers, and development of methods to determine the C-14 content of CO 2 and vegetation. Research in radiation biology included studies employing recombinant DNA technology, detection of damaged bases following uv irradiation, tumor induction studies, and work on improved heat resistance in yeast. Biomedical research included the completion of I-129 dose estimations in connection with a proposed waste repository

  14. Obtaining porous silicon suitable for sensor technology using MacEtch nonelectrolytic etching

    Directory of Open Access Journals (Sweden)

    Iatsunskyi I. R.

    2013-12-01

    Full Text Available The author suggests to use the etching method MacEtch (metal-assisted chemical etching for production of micro- and nanostructures of porous silicon. The paper presents research results on the morphology structures obtained at different parameters of deposition and etching processes. The research has shown that, depending on the parameters of deposition of silver particles and silicon wafers etching, the obtained surface morphology may be different. There may be both individual crater-like pores and developed porous or macroporous surface. These results indicate that the MacEtch etching is a promising method for obtaining micro-porous silicon nanostructures suitable for effective use in gas sensors and biological object sensors.

  15. Interaction of low-intensity nuclear radiation dose with the human blood: Using the new technique of CR-39NTDs for an in vitro study

    International Nuclear Information System (INIS)

    Ismail, Asaad H.; Jaafar, Mohamad S.

    2011-01-01

    Complete blood counts were analyzed for 30 samples of human blood with radiation dose rate ranging between 10 and 41 μSv/h using a Radium-226 source with different time of exposure. A new technique involving a nuclear track detector type CR-39(CR-39 NTDs) was used to estimate the alpha particle density incident on the blood samples. The results show that the ranges of alpha particle in blood samples and on the surface of CR-39NTDs vary exponentially with energy of alpha particles. This depends on the restricted energy loss and target density. Changes in the blood components due to irradiation occurred for different durations of irradiation, and the duration of irradiation that influenced the blood samples in this study was 6 min. The change in red blood cell (RBC) was negligible, so it is less affected than other blood components. In addition, most changes in the blood contents began at a low radiation dose (10.38-13.41 μSv/h). For the doses 13.41-21.77 μSv/h, platelet (PLT) counts increased rapidly and adversely with the RBC and white blood cell (WBC) due to chromosomal aberration. Besides, rapid PLT count reduction rapidly at high dose (42.1 μSv h) causes thrombocytopenia; in contrast, WBC increased, which is an indication of cancer caused due to increase in alpha particle dose. Generally, our results are in agreement with the essentials of blood content and the principles of biological radiation interaction.

  16. Calibration of CR-39 plastic detectors in various modes and radon measurement in the north-western region of Bangladesh

    International Nuclear Information System (INIS)

    Islam, G.S.; Islam, M.A.; Haque, A.K.F.

    1998-04-01

    Solid State track detectors have been extensively used for the measurement of time integrated radon levels in dwellings under different conditions. The CR-39 plastic detectors were calibrated for bare as well as cup with membrane mode, along with a mono dispersal aerosol 0.2μm in size in an exposure chamber, to find the relationship between track densities and the radon concentration as well as potential alpha energy concentration (WL) of radon. Measurement of the indoor radon and radon daughter concentrations were performed in houses in the north-western region of Bangladesh. In total 163 detectors were placed for measurement of indoor radon activities and 230 detectors for measurement of radon daughter concentrations. To study the underground radon activity, 114 CR-39 detectors in cylinders were used. The indoor radon activity in Naogaon was, in general, found to be higher than that in Rajshahi. The working levels in the mud-built houses were greater than that in brick-built houses. The underground radon activity of Naogaon was found to be 6 times higher than that of Rajshahi. No direct correlation was observed between the underground and indoor radon activity. The average values of radon activity and the working level for the north-western zone of Bangladesh are found to be 91 Bq. m -3 and 16 mWL respectively. (author)

  17. High throughput on-chip analysis of high-energy charged particle tracks using lensfree imaging

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Wei; Shabbir, Faizan; Gong, Chao; Gulec, Cagatay; Pigeon, Jeremy; Shaw, Jessica; Greenbaum, Alon; Tochitsky, Sergei; Joshi, Chandrashekhar [Electrical Engineering Department, University of California, Los Angeles, California 90095 (United States); Ozcan, Aydogan, E-mail: ozcan@ucla.edu [Electrical Engineering Department, University of California, Los Angeles, California 90095 (United States); Bioengineering Department, University of California, Los Angeles, California 90095 (United States); California NanoSystems Institute (CNSI), University of California, Los Angeles, California 90095 (United States)

    2015-04-13

    We demonstrate a high-throughput charged particle analysis platform, which is based on lensfree on-chip microscopy for rapid ion track analysis using allyl diglycol carbonate, i.e., CR-39 plastic polymer as the sensing medium. By adopting a wide-area opto-electronic image sensor together with a source-shifting based pixel super-resolution technique, a large CR-39 sample volume (i.e., 4 cm × 4 cm × 0.1 cm) can be imaged in less than 1 min using a compact lensfree on-chip microscope, which detects partially coherent in-line holograms of the ion tracks recorded within the CR-39 detector. After the image capture, using highly parallelized reconstruction and ion track analysis algorithms running on graphics processing units, we reconstruct and analyze the entire volume of a CR-39 detector within ∼1.5 min. This significant reduction in the entire imaging and ion track analysis time not only increases our throughput but also allows us to perform time-resolved analysis of the etching process to monitor and optimize the growth of ion tracks during etching. This computational lensfree imaging platform can provide a much higher throughput and more cost-effective alternative to traditional lens-based scanning optical microscopes for ion track analysis using CR-39 and other passive high energy particle detectors.

  18. Carrier-lifetime-controlled selective etching process for semiconductors using photochemical etching

    International Nuclear Information System (INIS)

    Ashby, C.I.H.; Myers, D.R.

    1992-01-01

    This patent describes a process for selectively photochemically etching a semiconductor material. It comprises introducing at least one impurity into at least one selected region of a semiconductor material to be etched to increase a local impurity concentration in the at least one selected region relative to an impurity concentration in regions of the semiconductor material adjacent thereto, for reducing minority carrier lifetimes within the at least one selected region relative to the adjacent regions for thereby providing a photochemical etch-inhibiting mask at the at least one selected region; and etching the semiconductor material by subjecting the surface of the semiconductor material to a carrier-driven photochemical etching reaction for selectively etching the regions of the semiconductor material adjacent the at least one selected region having the increase impurity concentration; wherein the step of introducing at least one impurity is performed so as not to produce damage to the at least one selected region before any etching is performed

  19. Etch Defect Characterization and Reduction in Hard-Mask-Based Al Interconnect Etching

    International Nuclear Information System (INIS)

    Lee, H.J.; Hung, C.L.; Leng, C.H.; Lian, N.T.; Young, L.W.

    2009-01-01

    This paper identifies the defect adders, for example, post hard-mask etch residue, post metal etch residue, and blocked etch metal island and investigates the removal characteristics of these defects within the oxide-masked Al etching process sequence. Post hard-mask etch residue containing C atom is related to the hardening of photoresist after the conventional post-RIE ashing at 275 degree C. An in situ O 2 -based plasma ashing on RIE etcher was developed to prevent the photoresist hardening from the high-ashing temperature; followed wet stripping could successfully eliminate such hardened polymeric residue. Post metal etch residue was caused from the attack of the Al sidewall by Cl atoms, and too much CHF 3 addition in the Al main etch step passivated the surface of Al resulting in poor capability to remove the Al-containing residue. The lower addition of CHF 3 in the Al main etch step would benefit from the residue removal. One possibility of blocked etch metal island creating was due to the micro masking formed on the opening of Ti N during the hard-mask patterning. We report that an additional Ti N surface pretreatment with the Ar/CHF 3 /N 2 plasmas could reduce the impact of the micro masking residues on blocked metal etch.

  20. Modeling the characteristic etch morphologies along specific crystallographic orientations by anisotropic chemical etching

    Directory of Open Access Journals (Sweden)

    Kun-Dar Li

    2018-02-01

    Full Text Available To improve the advanced manufacturing technology for functional materials, a sophisticated control of chemical etching process is highly demanded, especially in the fields of environment and energy related applications. In this study, a phase-field-based model is utilized to investigate the etch morphologies influenced by the crystallographic characters during anisotropic chemical etching. Three types of etching modes are inspected theoretically, including the isotropic, and preferred oriented etchings. Owing to the specific etching behavior along the crystallographic directions, different characteristic surface structures are presented in the simulations, such as the pimple-like, pyramidal hillock and ridge-like morphologies. In addition, the processing parameters affecting the surface morphological formation and evolution are also examined systematically. According to the numerical results, the growth mechanism of surface morphology in a chemical etching is revealed distinctly. While the etching dynamics plays a dominant role on the surface formation, the characteristic surface morphologies corresponding to the preferred etching direction become more apparent. As the atomic diffusion turned into a determinative factor, a smoothened surface would appear, even under the anisotropic etching conditions. These simulation results provide fundamental information to enhance the development and application of anisotropic chemical etching techniques.

  1. Modeling the characteristic etch morphologies along specific crystallographic orientations by anisotropic chemical etching

    Science.gov (United States)

    Li, Kun-Dar; Miao, Jin-Ru

    2018-02-01

    To improve the advanced manufacturing technology for functional materials, a sophisticated control of chemical etching process is highly demanded, especially in the fields of environment and energy related applications. In this study, a phase-field-based model is utilized to investigate the etch morphologies influenced by the crystallographic characters during anisotropic chemical etching. Three types of etching modes are inspected theoretically, including the isotropic, and preferred oriented etchings. Owing to the specific etching behavior along the crystallographic directions, different characteristic surface structures are presented in the simulations, such as the pimple-like, pyramidal hillock and ridge-like morphologies. In addition, the processing parameters affecting the surface morphological formation and evolution are also examined systematically. According to the numerical results, the growth mechanism of surface morphology in a chemical etching is revealed distinctly. While the etching dynamics plays a dominant role on the surface formation, the characteristic surface morphologies corresponding to the preferred etching direction become more apparent. As the atomic diffusion turned into a determinative factor, a smoothened surface would appear, even under the anisotropic etching conditions. These simulation results provide fundamental information to enhance the development and application of anisotropic chemical etching techniques.

  2. Development of a new approach to simulate a particle track under electrochemical etching in polymeric detectors

    International Nuclear Information System (INIS)

    Mostofizadeh, Ali; Huang, Yudong; Kardan, M. Reza; Babakhani, Asad; Sun Xiudong

    2012-01-01

    A numerical approach based on image processing was developed to simulate a particle track in a typical polymeric detector, e.g., polycarbonate, under electrochemical etching. The physical parameters such as applied voltage, detector thickness, track length, the radii of curvature at the tip of track, and the incidence angle of the particle were considered, and then the boundary condition of the problem was defined. A numerical method was developed to solve Laplace equation, and then the distribution of the applied voltage was obtained through the polymer volume. Subsequently, the electric field strengths in the detector elements were computed. In each step of the computation, an image processing technique was applied to convert the computed values to grayscale images. The results showed that a numerical solution to Laplace equation is dedicatedly an attractive approach to provide us the accurate values of electric field strength through the polymeric detector volume as well as the track area. According to the results, for a particular condition of the detector thickness equal to 445 μm, track length of 21 μm, the radii of 2.5 μm at track tip, the incidence angle of 90°, and the applied voltage of 2080 V, after computing Laplace equation for an extremely high population of 4000 × 4000 elements of detector, the average field strength at the tip of track was computed equal to 0.31 MV cm −1 which is in the range of dielectric strength for polymers. The results by our computation confirm Smythe’s model for estimating the ECE-tracks.

  3. CR-39 nuclear track detector application for the diagnostics of low energy high power ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Opekounov, M S; Pechenkin, S A; Remnev, G E [Nuclear Physics Institute, Tomsk (Russian Federation); Ivonin, I V [Siberian Physical-Technical Institute, Tomsk (Russian Federation)

    1997-12-31

    The results of investigation of the spectral composition of ion beams generated by the magneto-insulated ion diode of the MUK-M and TEMP accelerators. The energy and mass characteristics of the accelerated ion beam were determined by a Thomson spectrometer with a CR-39 plate detector (MOM - Atomki Nuclear Track Detector, Type MA-ND/p). The accelerated ion energy was from 40 to 240 keV. The ion current density range was from 1 to 10 A/cm{sup 2}. The mass composition contained hydrogen, nitrogen, carbon and aluminum ions. The individual track analysis showed the track form, depth and diameter in dependence on the ion mass and energy. (author). 2 figs., 5 refs.

  4. Hydrogen production from nano-porous Si powder formed by stain etching

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko, S.; Alekseev, S.; Kuznetsov, G.; Skryshevsky, V. [Institute of High Technology of National Taras Shevchenko University of Kyiv, Volodymyrs' ka 64, Kyiv 01601 (Ukraine); Lysenko, V.; Barbier, D. [Lyon Institute of Nanotechnologies (INL), CNRS UMR-5270, University of Lyon, INSA de Lyon, 7 avenue Jean Capelle, Bat. Blaise Pascal, 69621 Villeurbanne Cedex (France); Venturello, A.; Geobaldo, F.; Garrone, E. [Politecnico di Torino, Department of Materials Science and Chemical Engineering, 10129 Torino (Italy); Gulina, L.; Tolstoy, V. [St-Petersburg State University, Chemical Department (Russian Federation)

    2010-07-15

    Hydrogen reservoirs based on porous silicon (PS) nanostructures are considered. Silicon-based hydrogen tanks are believed to be applicable for portable device energy supply and compatible with micro-sources of energy of new generation. Stain etching of silicon powder to produce PS is studied as a technology alternative to conventional electrochemical etching and application of the PS powder for hydrogen production is also described. Size selection of initial Si micro-particles constituting the powders was carried out by sedimentation technique. Hydrogen content in PS was investigated by FTIR spectroscopy. Extraction of hydrogen in water environment in presence of small amount of NH{sub 3} as catalyst was shown to have advantages such as safety and tunability, additional production of hydrogen from water dissociation, and a possibility to characterize PS as a hydrogen source material in terms of hydrogen effective shell and crystalline core conception. (author)

  5. Effect of chemical etching on the Cu/Ni metallization of poly (ether ether ketone)/carbon fiber composites

    International Nuclear Information System (INIS)

    Di Lizhi; Liu Bin; Song Jianjing; Shan Dan; Yang Dean

    2011-01-01

    Poly(ether ether ketone)/carbon fiber composites (PEEK/Cf) were chemical etched by Cr 2 O 3 /H 2 SO 4 solution, electroless plated with copper and then electroplated with nickel. The effects of chemical etching time and temperature on the adhesive strength between PEEK/Cf and Cu/Ni layers were studied by thermal shock method. The electrical resistance of some samples was measured. X-ray photoelectron spectroscopy (XPS) was used to analyze the surface composition and functional groups. Scanning electron microscopy (SEM) was performed to observe the surface morphology of the composite, the chemical etched sample, the plated sample and the peeled metal layer. The results indicated that C=O bond increased after chemical etching. With the increasing of etching temperature and time, more and more cracks and partially exposed carbon fibers appeared at the surface of PEEK/Cf composites, and the adhesive strength increased consequently. When the composites were etched at 60 deg. C for 25 min and at 70-80 deg. C for more than 15 min, the Cu/Ni metallization layer could withstand four thermal shock cycles without bubbling, and the electrical resistivity of the metal layer of these samples increased with the increasing of etching temperature and time.

  6. The possibility of multi-layer nanofabrication via atomic force microscope-based pulse electrochemical nanopatterning

    Science.gov (United States)

    Kim, Uk Su; Morita, Noboru; Lee, Deug Woo; Jun, Martin; Park, Jeong Woo

    2017-05-01

    Pulse electrochemical nanopatterning, a non-contact scanning probe lithography process using ultrashort voltage pulses, is based primarily on an electrochemical machining process using localized electrochemical oxidation between a sharp tool tip and the sample surface. In this study, nanoscale oxide patterns were formed on silicon Si (100) wafer surfaces via electrochemical surface nanopatterning, by supplying external pulsed currents through non-contact atomic force microscopy. Nanoscale oxide width and height were controlled by modulating the applied pulse duration. Additionally, protruding nanoscale oxides were removed completely by simple chemical etching, showing a depressed pattern on the sample substrate surface. Nanoscale two-dimensional oxides, prepared by a localized electrochemical reaction, can be defined easily by controlling physical and electrical variables, before proceeding further to a layer-by-layer nanofabrication process.

  7. Vertically aligned cobalt hydroxide nano-flake coated electro-etched carbon fiber cloth electrodes for supercapacitors

    Science.gov (United States)

    Cheng, Qian; Tang, Jie; Zhang, Han; Qin, Lu-Chang

    2014-11-01

    We describe preparation and characterization of nanostructured electrodes using Co(OH)2 nano-flakes and carbon fiber cloth for supercapacitors. Nanostructured Co(OH)2 flakes are produced by electrodeposition and they are coated onto the electro-etched carbon fiber cloth. A highest specific capacitance of 3404.8 F g-1 and an area-normalized specific capacitance of 3.3 F cm-2 have been obtained from such electrodes. Morphology and structure of the nanostructured electrodes have been characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical properties have been studied by cyclic voltammetry (CV), constant-current charge and discharge, electrochemical impedance spectroscopy (EIS), and long-time cycling.

  8. Influence of Pre-etching Times on Fatigue Strength of Self-etch Adhesives to Enamel.

    Science.gov (United States)

    Takamizawa, Toshiki; Barkmeier, Wayne W; Tsujimoto, Akimasa; Endo, Hajime; Tsuchiya, Kenji; Erickson, Robert L; Latta, Mark A; Miyazaki, Masashi

    To use shear bond strength (SBS) and shear fatigue strength (SFS) testing to determine the influence of phosphoric acid pre-etching times prior to application of self-etch adhesives on enamel bonding. Two single-step self-etch universal adhesives (Prime&Bond Elect and Scotchbond Universal), a conventional single-step self-etch adhesive (G-ӕnial Bond), and a conventional two-step self-etch adhesive (OptiBond XTR) were used. The SBS and SFS were obtained with phosphoric acid pre-etching for 3, 10, or 15 s prior to application of the adhesives, and without pre-etching (0 s) as a control. A staircase method was used to determine the SFS with 10 Hz frequency for 50,000 cycles or until failure occurred. The mean demineralization depth for each treated enamel surface was also measured using a profilometer. For all the adhesives, the groups with pre-etching showed significantly higher SBS and SFS than groups without pre-etching. However, there was no significant difference in SBS and SFS among groups with > 3 s of preetching. In addition, although the groups with pre-etching showed significantly deeper demineralization depths than groups without pre-etching, there was no significant difference in depth among groups with > 3 s of pre-etching. Three seconds of phosphoric acid pre-etching prior to application of self-etch adhesive can enhance enamel bonding effectiveness.

  9. Development of neutron personnel monitoring system based on CR-39 solid state nuclear track detector

    International Nuclear Information System (INIS)

    Massand, O.P.; Kundu, H.K.; Marathe, P.K.; Supe, S.J.

    1990-01-01

    Personnel neutron monitoring aims at providing a method to evaluate the magnitude of the detrimental effects on the personnel exposed to neutrons. Neutron monitoring is done for a small though growing number of personnel working with neutrons in a wide range of situations. Over the years, many solid state nuclear track detectors (SSNTD) have been tried for neutron personnel monitoring. CR-39 SSNTD is a proton sensitive polymer and offers a lot of promise for neutron personnel monitoring due to its high sensitivity and lower energy threshold for neutron detection. This report presents the mechanism of track formation in this polymer, the development of this neutron personnel monitoring system in our laboratory, its various characteristics and its promise as a routine personnel neutron monitor. (author). 1 tab., 7 figs

  10. Self-etching adhesive on intact enamel, with and without pre-etching.

    Science.gov (United States)

    Devarasa, G M; Subba Reddy, V V; Chaitra, N L; Swarna, Y M

    2012-05-01

    Bond strengths of composite resin to enamel using self-etch adhesive (SEA) Clearfil SE bond system on intact enamel and enamel pre-etched with phosphoric acid were compared. The objective was to determine if the pre-etching would increase the bond strengths of the SEA systems to intact enamel and to evaluate the effect of pre-etching on bond formation of self-etch adhesives on intact enamel. Labial surfaces of 40 caries free permanent upper central and lateral incisors were cleaned, sectioned of their roots. All specimens were mounted on acrylic block and divided randomly into four groups. In two groups the application of self-etch adhesive, Clearfil SE bond was carried as per manufacturer's instructions, composite cylinders were built, whereas in the other two groups, 37% phosphoric acid etching was done before the application of self-etching adhesives. Then the resin tags were analyzed using scanning electron microscope and shear bond strength was measured using Instron universal testing machine. When phosphoric acid was used, there was significant increase in the depth of penetration of resin tags and in the Shear Bond Strength of composite to enamel. The results indicate that out of both treatment groups, pre-etching the intact enamel with 37% phosphoric acid resulted in formation of longer resin tags and higher depth of penetration of resin tags of the Clearfil SE bond, and attaining higher bond strength of the Clearfil SE bond to intact enamel. Copyright © 2011 Wiley Periodicals, Inc.

  11. Fragmentation cross section measurements of iron projectiles using CR-39 plastic nuclear track detectors

    CERN Document Server

    Flesch, F; Huentrup, G; Roecher, H; Streibel, T; Winkel, E; Heinrich, W

    1999-01-01

    For long term space missions in which larger radiation doses are accumulated it is necessary to improve the precision of models predicting the space radiation environment. Different models are available to determine the flux of cosmic ray heavy ions behind shielding material. The accuracy of these predictions depends on the knowledge of the fragmentation cross sections, especially at energies of several hundred MeV/nucleon, where the particle flux is at a maximum and especially for those particles with high LET, i.e. iron nuclei. We have measured fragmentation cross sections of sup 5 sup 6 Fe projectiles at beam energies of 700 and 1700 A MeV using experimental set-ups with plastic nuclear track detectors. In this paper we describe the experimental technique to study the fragmentation reactions of sup 5 sup 6 Fe projectiles using CR-39 plastic nuclear track detectors. Results for different targets are presented.

  12. Change of Cr-39(DOP) track detector response as a result of space exposure

    International Nuclear Information System (INIS)

    Yadav, J.S.; Singh, R.K.

    1990-01-01

    The response functions for CR-39(DOP) plastic track detectors are calculated, using the simplex method for nonlinear least squares fit, from experimental data obtained from accelerator beams as well as space exposure. The average detector sensitivity is reduced by over 30% in the case of space exposure. The average charge shift for the oxygen group is one charge unit, and it increases with particle charge. The effect decreases with restricted energy loss, which is contrary to that observed in the registration temperature effect. We have discussed various environmental parameters which may produce the observed effect. The registration temperature effect may account for the observed effect (within the errors) for the worst case (temperature) analysis. However, a more reasonable estimate suggests that both the registration temperature as well as pressure during exposure contribute to the observed effect. To discriminate between the separate contributions, further experimental data is needed. (author)

  13. Dry etching technology for semiconductors

    CERN Document Server

    Nojiri, Kazuo

    2015-01-01

    This book is a must-have reference to dry etching technology for semiconductors, which will enable engineers to develop new etching processes for further miniaturization and integration of semiconductor integrated circuits.  The author describes the device manufacturing flow, and explains in which part of the flow dry etching is actually used. The content is designed as a practical guide for engineers working at chip makers, equipment suppliers and materials suppliers, and university students studying plasma, focusing on the topics they need most, such as detailed etching processes for each material (Si, SiO2, Metal etc) used in semiconductor devices, etching equipment used in manufacturing fabs, explanation of why a particular plasma source and gas chemistry are used for the etching of each material, and how to develop etching processes.  The latest, key technologies are also described, such as 3D IC Etching, Dual Damascene Etching, Low-k Etching, Hi-k/Metal Gate Etching, FinFET Etching, Double Patterning ...

  14. Passive and transpassive behaviour of CoCrMo in simulated biological solutions

    International Nuclear Information System (INIS)

    Hodgson, A.W.E.; Kurz, S.; Virtanen, S.; Fervel, V.; Olsson, C.-O.A.; Mischler, S.

    2004-01-01

    In this work, the behaviour of a CoCrMo alloy under simulated body conditions was investigated. More specifically, the electrochemical properties of the alloy and the relevant mechanisms in the passive and transpassive states were studied in detail. Electrochemical techniques such as potentiodynamic and potentiostatic polarisation, cyclic voltammetry, rotating disc electrode and electrochemical impedance spectroscopy were employed. Further, ex situ X-ray photoelectron spectroscopy analysis of the passive films was carried out. A good correlation between the results obtained from all the experimental techniques was achieved. Overall, it was found that the passive film on CoCrMo changed in composition and thickness with both potential and time. The passive behaviour of the CrCrMo alloy is due to a formation an oxide film highly enriched with Cr (∼90% Cr oxides) on the alloy surface. The passive and transpassive behaviour of the alloy is hence dominated by the alloying element Cr. In the transpassive region, strong thickening of the oxide film takes place, combined with a change in the composition of the film, and strongly increased dissolution rate. In the transpassive region, all alloying elements dissolve according to the composition of the alloy. The metal ion release is also very strongly enhanced by cyclic variation of the potential between reducing and oxidizing conditions. In this case, during activation/repassivation cycles, cobalt dissolution is greater than expected from the composition of the alloy. Therefore, active dissolution behaviour is mainly dominated by the alloying element Co

  15. Auto-counting of high density overlapping tracks and neutron spectrum measurement using CR-39 detectors and in-house image analysis program

    International Nuclear Information System (INIS)

    Paul, Sabyasachi; Tripathy, S.P.; Sahoo, G.S.; Joshi, D.S.; Bandyopadhyay, T.

    2014-01-01

    An effort is made in this work to overcome the difficulty of counting highly dense and overlapping tracks in solid polymeric track detectors (SPTD) such as CR-39. A program is developed to automatically count the track density which is found to be faster and more precise compared to other commonly used image analysing software. The results obtained by the present methodology are compared with those obtained using other software. (author)

  16. Study of Thermal Electrical Modified Etching for Glass and Its Application in Structure Etching

    Directory of Open Access Journals (Sweden)

    Zhan Zhan

    2017-02-01

    Full Text Available In this work, an accelerating etching method for glass named thermal electrical modified etching (TEM etching is investigated. Based on the identification of the effect in anodic bonding, a novel method for glass structure micromachining is proposed using TEM etching. To validate the method, TEM-etched glasses are prepared and their morphology is tested, revealing the feasibility of the new method for micro/nano structure micromachining. Furthermore, two kinds of edge effect in the TEM and etching processes are analyzed. Additionally, a parameter study of TEM etching involving transferred charge, applied pressure, and etching roughness is conducted to evaluate this method. The study shows that TEM etching is a promising manufacture method for glass with low process temperature, three-dimensional self-control ability, and low equipment requirement.

  17. Corrosion Resistance of Co-Cr-Mo Alloy Used in Dentistry

    Directory of Open Access Journals (Sweden)

    Łukaszczyk A.

    2015-04-01

    Full Text Available The presented paper studies the effect of the casting technology on the corrosion resistance of Co-Cr-Mo alloy. The investigations were conducted on a commercial alloy with the brand name ARGELOY N.P SPECIAL (Co-Cr-Mo produced by Argen as well as the same alloy melted and cast by the lost wax casting method performed by a dental technician. The corrosion behavior of the dental alloys in an artificial saliva was studied with the use of the following electrochemical techniques: open circuit potential and voltammetry. After the electrochemical tests, studies of the surface of the examined alloys were performed by means of a scanning electron microscope with an X-ray microanalyzer. The results of the electrochemical studies show that the dependence of the corrosion resistance on the microstructure associated with the recasting process is marginal. The results of the electrochemical studies of the considered alloy clearly point to their good corrosion resistance in the discussed environment.

  18. Formation of a silicon micropore array of a two-dimension electron multiplier by photo electrochemical etching

    International Nuclear Information System (INIS)

    Gao Yanjun; Duanmu Qingduo; Wang Guozheng; Li Ye; Tian Jingquan

    2009-01-01

    A semiconductor PEC etching method is applied to fabricate the n-type silicon deep micropore channel array. In this method, it is important to arrange the direction of the micropore array along the crystal orientation of the Si substrate. Otherwise, serious lateral erosion will happen. The etching process is also relative to the light intensity and HF concentration. 5% HF concentration and 10-15 cm distance between the light source and the silicon wafer are demonstrated to be the best in our experiments. The n-type silicon deep micropore channel array with aperture of 3 μm and aspect ratio of 40-60, whose inner walls are smooth, is finally obtained.

  19. Bulk-compositional changes of Ni2Al3 and NiAl3 during ion etching

    International Nuclear Information System (INIS)

    Chen Houwen; Wang Rong

    2008-01-01

    Bulk-compositional changes of Ni 2 Al 3 and NiAl 3 in a Ni-50 wt% Al alloy during ion etching have been investigated by transmission electron microscopy and energy dispersive X-ray spectroscopic analyses. After etching with 7, 5 and 3 keV Ar + ions for 15, 24 and 100 h nickel contents in both Ni 2 Al 3 and NiAl 3 exceeded greatly those in the initial compounds and increased with the decrement of the sputtering energy. After 100 h etching with 3 keV Ar + ions the compositions of these two compounds reached a similar value, about Ni 80-83 Al 12-15 Fe 3-4 Cr 1-2 (at%). A synergistic action of preferential sputtering, radiation-induced segregation and radiation-enhanced diffusion enables the altered-layers at the top and bottom of the film extend through the whole film. The bulk-compositional changes are proposed to occur in the unsteady-state sputtering regime of ion etching and caused by an insufficient supply of matter in a thin film

  20. Track Detection Technique Using CR-39 for Determining Depleted Uranium in Biological Specimens

    International Nuclear Information System (INIS)

    Murbat, S.M.

    2013-01-01

    Track detecting technique using CR-39 track detector has been implemented for determining depleted uranium concentration in biological specimens (tissues, bones, and blood) of patients infected with cancer diseases. Results were compared with specimens of patients infected with conventional diseases (noncancerous). Specimens were collected from middle and south of Iraq have been contaminated with depleted uranium in the Gulf war in 1991. Results show that this technique is efficient for determining depleted uranium concentration in biological specimens. It was found that all studies samples determine for patients infected with cancer diseases contain a high concentration of depleted uranium (more than the international standard) comparing with noncancerous diseases. Moreover, it was found that persons infected with Leukemia show more sensitive to uranium concentrations to induce the diseases (66-202 ppb), while (116- 1910 ppb) concentrations were needed for inducing cancer diseases in organs and tissues. Result confirmed the correlation between cancerous diseases and the munitions made of depleted uranium used in the Gulf war in 1991 leads to contaminate the Iraqi environment and causes a high risk against people in Iraq.

  1. Redox buffered hydrofluoric acid etchant for the reduction of galvanic attack during release etching of MEMS devices having noble material films

    Science.gov (United States)

    Hankins, Matthew G [Albuquerque, NM

    2009-10-06

    Etchant solutions comprising a redox buffer can be used during the release etch step to reduce damage to the structural layers of a MEMS device that has noble material films. A preferred redox buffer comprises a soluble thiophosphoric acid, ester, or salt that maintains the electrochemical potential of the etchant solution at a level that prevents oxidation of the structural material. Therefore, the redox buffer preferentially oxidizes in place of the structural material. The sacrificial redox buffer thereby protects the exposed structural layers while permitting the dissolution of sacrificial oxide layers during the release etch.

  2. Silicon etch process

    International Nuclear Information System (INIS)

    Day, D.J.; White, J.C.

    1984-01-01

    A silicon etch process wherein an area of silicon crystal surface is passivated by radiation damage and non-planar structure produced by subsequent anisotropic etching. The surface may be passivated by exposure to an energetic particle flux - for example an ion beam from an arsenic, boron, phosphorus, silicon or hydrogen source, or an electron beam. Radiation damage may be used for pattern definition and/or as an etch stop. Ethylenediamine pyrocatechol or aqueous potassium hydroxide anisotropic etchants may be used. The radiation damage may be removed after etching by thermal annealing. (author)

  3. Measurement of target fragments produced by 160 MeV proton beam in aluminum and polyethylene with CR-39 plastic nuclear track detectors

    Czech Academy of Sciences Publication Activity Database

    Ambrožová, Iva; Yasuda, N.; Kodaira, S.; Sihver, L.

    2014-01-01

    Roč. 64, MAY (2014), s. 29-34 ISSN 1350-4487 R&D Projects: GA AV ČR KJB100480901; GA AV ČR IAA100480902; GA MŠk LG14004 Institutional support: RVO:61389005 Keywords : target fragments * high-energy protons * Aluminium * Polyethylene * plastic nuclear track detectors * CR-39 Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.213, year: 2014

  4. Electrochemical behavior of single layer CrN, TiN, TiAlN coatings and nanolayered TiAlN/CrN multilayer coatings prepared by reactive direct current magnetron sputtering

    International Nuclear Information System (INIS)

    William Grips, V.K.; Barshilia, Harish C.; Selvi, V. Ezhil; Kalavati; Rajam, K.S.

    2006-01-01

    The corrosion behaviors of single layer TiN, CrN, TiAlN and multilayer TiAlN/CrN coatings, deposited on steel substrate using a multi-target reactive direct current magnetron sputtering process, were studied in 3.5% NaCl solution by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The total thickness of the coatings was about 1.5 μm. About 0.5 μm thick chromium interlayer was used for improved adhesion of the coatings. The potentiodynamic polarization measurements showed that for all the coatings the corrosion potential shifted to higher values as compared to the uncoated substrate. Similarly, the corrosion current density decreased for coated samples, indicating better corrosion resistance of the coated samples. The multilayer coatings of TiAlN/CrN exhibited superior corrosion behavior as compared to the single layer coatings. The Nyquist and the Bode plots obtained from the EIS measurements were fitted by appropriate equivalent circuits to calculate the pore resistance, the charge transfer resistance and the capacitance. These studies revealed that the pore resistance was lowest for TiN coatings, which increased for TiAlN coatings. TiAlN/CrN multilayer coatings exhibited highest pore resistance. No significant change in the capacitive behavior of the coatings was observed, suggesting minimal morphological changes as a result of immersion in the electrolyte. This could be attributed to shorter immersion durations. These studies were confirmed by examining the corroded samples under scanning electron microscope. Preliminary experiments conducted with additional interlayer of electroless nickel (5.0 μm thick) have shown significant improvement in the corrosion resistance of the coatings

  5. Assessment of radiation shielding materials for protection of space crews using CR-39 plastic nuclear track detector

    International Nuclear Information System (INIS)

    DeWitt, J.M.; Benton, E.R.; Uchihori, Y.; Yasuda, N.; Benton, E.V.; Frank, A.L.

    2009-01-01

    A significant obstacle to long duration human space exploration such as the establishment of a permanent base on the surface of the Moon or a human mission to Mars is the risk posed by prolonged exposure to space radiation. In order to keep mission costs at acceptable levels while simultaneously minimizing the risk from radiation to space crew health and safety, a judicious use of optimized shielding materials will be required. We have undertaken a comprehensive study using CR-39 plastic nuclear track detector (PNTD) to characterize the radiation shielding properties of a range of materials-both common baseline materials such as Al and polyethylene, and novel multifunctional materials such as carbon composites-at heavy ion accelerators. The study consists of analyzing CR-39 PNTD exposed in front of and behind shielding targets of varying composition and at a number of depths (target thicknesses) relevant to the development and testing of materials for space radiation shielding. Most targets consist of 10 cm x 10 cm slabs of solid materials ranging in thickness from 1 to >30 g/cm 2 . Exposures have been made to beams of C, O, Ne, Si, Ar, and Fe at energies ranging from 290 MeV/amu to 1 GeV/amu at the National Institute of Radiological Sciences HIMAC and the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory. Analysis of the exposed detectors yields LET spectrum, dose, and dose equivalent as functions of target depth and composition, and incident heavy ion charge, energy, and fluence. Efforts are currently underway to properly weigh and combine these results into a single quantitative estimate of a material's ability to shield space crews from the interplanetary galactic cosmic ray flux.

  6. Influence of different pre-etching times on fatigue strength of self-etch adhesives to dentin.

    Science.gov (United States)

    Takamizawa, Toshiki; Barkmeier, Wayne W; Tsujimoto, Akimasa; Suzuki, Takayuki; Scheidel, Donal D; Erickson, Robert L; Latta, Mark A; Miyazaki, Masashi

    2016-04-01

    The purpose of this study was to use shear bond strength (SBS) and shear fatigue strength (SFS) testing to determine the influence on dentin bonding of phosphoric acid pre-etching times before the application of self-etch adhesives. Two single-step self-etch universal adhesives [Prime & Bond Elect (EL) and Scotchbond Universal (SU)], a conventional single-step self-etch adhesive [G-aenial Bond (GB)], and a two-step self-etch adhesive [OptiBond XTR (OX)] were used. The SBS and SFS values were obtained with phosphoric acid pre-etching times of 3, 10, or 15 s before application of the adhesives, and for a control without pre-etching. For groups with 3 s of pre-etching, SU and EL showed higher SBS values than control groups. No significant difference was observed for GB among the 3 s, 10 s, and control groups, but the 15 s pre-etching group showed significantly lower SBS and SFS values than the control group. No significant difference was found for OX among the pre-etching groups. Reducing phosphoric acid pre-etching time can minimize the adverse effect on dentin bonding durability for the conventional self-etch adhesives. Furthermore, a short phosphoric acid pre-etching time enhances the dentin bonding performance of universal adhesives. © 2016 Eur J Oral Sci.

  7. The study of Cr3+/Cr2+ redox system by polarographic method

    Directory of Open Access Journals (Sweden)

    S. A. Pokhmyolkina

    2014-08-01

    Full Text Available Aim. The relevance of the theme is the ability to determine kinetic and thermodynamic parameters of the redox system on the example of Сr3/ Cr2in order to explain the reaction mechanism. In this paper, the electrochemical behavior of Cr+3/ Cr+2has been studied by polarography method. Polarogramshave been interpreted using the theory of irreversible polarographic waves and thermodynamically irreversible processes. Experiments have been carried out in a sealed cell with an outer casing for temperature control. Air oxygen removed from the feed solution for 15-20 minutes, purified nitrogen flowing from the cylinder. Characterization of the capillary in a 0.1N solution.H2SO4: mass flowing mercury m = 2,39 mg / sec; droplet formation period τ = 1,25 sec. Sulfate Cr (II was prepared by dissolving an electrolytic chromium 150 cm3 of water and 46 grams of 98 % sulphate acid. Thus a saturated solution formed a blue color. Sulfate salt solutions of two- and trivalent chromium in the medium of 0.1NH2SO4 give one wave. Anodic diffusion current sulfate Cr (II was 4,67μa, and half-wave potential E ½ = -0,44 V. The cathode current diffuse sulfate Cr (III, respectively - 7,65μa and E ½ = - 1,01 V. Inconsistency half-wave potentials of anodic and cathodic processes indicates its irreversibility. Half-wave potentials are given with respect to a saturated calomel electrode. Polarogramshave been investigated in the temperature range of 20-600C every 100C. Temperature coefficients have been calculated by the equation: Β% = idt –id20/ id20Δt, whereidtis diffusion current for a given concentration of the test solution at t0С; id20 is diffusion current for the same concentration at 200C; Δt - temperature change relative to 200C . Irreversibility, obviously due to the change in the electron configuration of chromium electrode is accompanying the redox process.Using the theory of irreversible polarographic waves we have determined the kinetic characteristics

  8. Reduction of Cr(VI) to Cr(III) using silicon nanowire arrays under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Fellahi, Ouarda [Institut d' Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, Avenue Poincaré—BP 70478, 59652 Villeneuve d' Ascq Cedex (France); Centre de Recherche en Technologie des Semi-conducteurs pour l' Energétique-CRTSE 02, Bd Frantz Fanon, BP. 140, Alger 7 Merveilles (Algeria); Barras, Alexandre [Institut d' Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, Avenue Poincaré—BP 70478, 59652 Villeneuve d' Ascq Cedex (France); Pan, Guo-Hui [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Dong Nanhu Road, Changchun 130033 (China); Coffinier, Yannick [Institut d' Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, Avenue Poincaré—BP 70478, 59652 Villeneuve d' Ascq Cedex (France); Hadjersi, Toufik [Centre de Recherche en Technologie des Semi-conducteurs pour l' Energétique-CRTSE 02, Bd Frantz Fanon, BP. 140, Alger 7 Merveilles (Algeria); Maamache, Mustapha [Laboratoire de Physique Quantique et Systèmes Dynamiques, Département de Physique, Université de Sétif, Sétif 19000 (Algeria); Szunerits, Sabine [Institut d' Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, Avenue Poincaré—BP 70478, 59652 Villeneuve d' Ascq Cedex (France); and others

    2016-03-05

    Highlights: • Cr(VI) reduction to Cr(III) using silicon nanowires decorated with Cu nanoparticles. • The reduction takes place at room temperature and neutral pH under visible light. • The photocatalytic reduction was enhanced by addition of adipic or citric acid. - Abstract: We report an efficient visible light-induced reduction of hexavalent chromium Cr(VI) to trivalent Cr(III) by direct illumination of an aqueous solution of potassium dichromate (K{sub 2}Cr{sub 2}O{sub 7}) in the presence of hydrogenated silicon nanowires (H-SiNWs) or silicon nanowires decorated with copper nanoparticles (Cu NPs-SiNWs) as photocatalyst. The SiNW arrays investigated in this study were prepared by chemical etching of crystalline silicon in HF/AgNO{sub 3} aqueous solution. The Cu NPs were deposited on SiNW arrays via electroless deposition technique. Visible light irradiation of an aqueous solution of K{sub 2}Cr{sub 2}O{sub 7} (10{sup −4} M) in presence of H-SiNWs showed that these substrates were not efficient for Cr(VI) reduction. The reduction efficiency achieved was less than 10% after 120 min irradiation at λ > 420 nm. Addition of organic acids such as citric or adipic acid in the solution accelerated Cr(VI) reduction in a concentration-dependent manner. Interestingly, Cu NPs-SiNWs was found to be a very efficient interface for the reduction of Cr(VI) to Cr(III) in absence of organic acids. Almost a full reduction of Cr(VI) was achieved by direct visible light irradiation for 140 min using this photocatalyst.

  9. Determination Of Uranium Concentration In Teeth Female Samples Using Fission Tracks In CR-39 From Different Countries

    International Nuclear Information System (INIS)

    Hummadi, S.S

    2010-01-01

    The present study was under taken to measure the uranium concentration in female teeth samples collected from different nationalities.The determination of uranium concentration in these samples has been done by using CR-39 track detector.The nuclear reaction is used as a source of nuclear fission fragments is (n, f) obtained by the bombardment of U-235 with thermal neutrons with flux (5*10 3 n/cm 2 .s) was used from (Am-Be) neutron source.The obtained results show the concentration is ranging from (0.58±0.7ppm) in Oman and Uae to (0.35±0.03ppm)in Iraqi for male, the uranium concentration was the highest in Oman and Uae for female

  10. Shear bond strength of composite bonded with three adhesives to Er,Cr:YSGG laser-prepared enamel.

    Science.gov (United States)

    Türkmen, Cafer; Sazak-Oveçoğlu, Hesna; Günday, Mahir; Güngör, Gülşad; Durkan, Meral; Oksüz, Mustafa

    2010-06-01

    To assess in vitro the shear bond strength of a nanohybrid composite resin bonded with three adhesive systems to enamel surfaces prepared with acid and Er,Cr:YSGG laser etching. Sixty extracted caries- and restoration-free human maxillary central incisors were used. The teeth were sectioned 2 mm below the cementoenamel junction. The crowns were embedded in autopolymerizing acrylic resin with the labial surfaces facing up. The labial surfaces were prepared with 0.5-mm reduction to receive composite veneers. Thirty specimens were etched with Er,Cr:YSGG laser. This group was also divided into three subgroups, and the following three bonding systems were then applied on the laser groups and the other three unlased groups: (1) 37% phosphoric acid etch + Bond 1 primer/adhesive (Pentron); (2) Nano-bond self-etch primer (Pentron) + Nano-bond adhesive (Pentron); and (3) all-in-one adhesive-single dose (Futurabond NR, Voco). All of the groups were restored with a nanohybrid composite resin (Smile, Pentron). Shear bond strength was measured with a Zwick universal test device with a knife-edge loading head. The data were analyzed with two-factor ANOVA. There were no significant differences in shear bond strength between self-etch primer + adhesive and all-in-one adhesive systems for nonetched and laser-etched enamel groups (P > .05). However, bond strength values for the laser-etched + Bond 1 primer/adhesive group (48.00 +/- 13.86 MPa) were significantly higher than the 37% phosphoric acid + Bond 1 primer/adhesive group (38.95 +/- 20.07 MPa) (P enamel surface more effectively than 37% phosphoric acid for subsequent attachment of composite material.

  11. Progress report: Health Sciences Division, 1982 January 1 to March 31

    International Nuclear Information System (INIS)

    1982-07-01

    Investigations of etching methods of CR-39 plastic used to detect fission fragment damage tracks has led to a preliminary chemical etching before the electrochemical etch. Leakage spectrum calculations of a D 2 O-moderated 252 Cf source suitable for neutron dosimeter calibration have been completed. The Gaussian plume model for short range atmospheric dispersion of radionuclides is being modified to account for roughness of local terrain. A capillary effect in soils, just above a watertable has been shown to be a possible mechanism whereby large hydraulic head changes and later large groundwater fluxes can be induced by relatively small additions of water. Studies of radiation damage to human DNA continue, and include also DNA damage caused by other chemical and physical factors, such as hyperthermia treatment; and the ability of human white blood cells to damage mouse cell DNA. A paper describing dose conversion factors used in the Canadian waste disposal assessment was prepared. Equipment measuring parameters of metal ion-amino acid reactions is now working, and computer programs to analyze results are being installed. A literature review report on this topic is in the final preparation stages. A computer record-keeping system for individual monitoring results is being developed

  12. Charge-transfer interactions of Cr species with DNA.

    Science.gov (United States)

    Nowicka, Anna M; Matysiak-Brynda, Edyta; Hepel, Maria

    2017-10-01

    Interactions of Cr species with nucleic acids in living organisms depend strongly on Cr oxidation state and the environmental conditions. As the effects of these interactions range from benign to pre-mutagenic to carcinogenic, careful assessment of the hazard they pose to human health is necessary. We have investigated methods that would enable quantifying the DNA damage caused by Cr species under varying environmental conditions, including UV, O 2 , and redox potential, using simple instrumental techniques which could be in future combined into a field-deployable instrumentation. We have employed electrochemical quartz crystal nanogravimetry (EQCN), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) to evaluate the extent of DNA damage expressed in terms of guanine oxidation yield (η) and changes in specific characteristics provided by these techniques. The effects of the interactions of Cr species with DNA were analyzed using a model calf thymus DNA (ctDNA) film on a gold electrode (Au@ctDNA) in different media, including: (i) Cr(VI), (ii) Cr(VI) reduced at -0.2V, (iii) Cr(III)+UV radiation+O 2 , and Cr(III), obtaining the η values: 7.4±1.4, 1.5±0.4, 1.1±0.31%, and 0%, respectively, thus quantifying the hazard posed. The EIS measurements have enabled utilizing the decrease in charge-transfer resistance (R ct ) for ferri/ferrocyanide redox probe at an Au@ctDNA electrode to assess the oxidative ctDNA damage by Cr(VI) species. In this case, circular dichroism indicates an extensive damage to the ctDNA hydrogen bonding. On the other hand, Cr(III) species have not induced any damage to ctDNA, although the EQCN measurements show an electrostatic binding to DNA. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Inductively coupled plasma etching of III-V antimonides in BCl3/SiCl4 etch chemistry

    International Nuclear Information System (INIS)

    Swaminathan, K.; Janardhanan, P.E.; Sulima, O.V.

    2008-01-01

    Inductively coupled plasma etching of GaSb using BCl 3 /SiCl 4 etch chemistry has been investigated. The etch rates were studied as a function of bias power, inductively coupled plasma source power, plasma chemistry and chamber pressure. The etched surfaces remain smooth and stoichiometric over the entire range of plasma conditions investigated. The knowledge gained in etching GaSb was applied to etching AlGaAsSb and InGaAsSb in order to fabricate heterojunction phototransistors. As expected, InGaAsSb etch rate was much lower compared to the corresponding value for GaSb, mainly due to the relatively low volatility of indium chlorides. For a wide range of plasma conditions, the selectivity between GaSb and AlGaAsSb was close to unity, which is desirable for fabricating etched mirrors and gratings for Sb-based mid-infrared laser diodes. The surface roughness and the etch profile were examined for the etched GaSb, AlGaAsSb and InGaAsSb samples using scanning electron microscope. The high etch rates achieved (∼ 4 μm/min) facilitated deep etching of GaSb. A single layer, soft mask (AZ-4903 photoresist) was used to etch GaSb, with etch depth ∼ 90 μm. The deep dry etching of GaSb has many important applications including etching substrate windows for backside-illuminated photodetectors for the mid-infrared wavelength range

  14. High performance lithium insertion negative electrode materials for electrochemical devices

    Energy Technology Data Exchange (ETDEWEB)

    Channu, V.S. Reddy, E-mail: chinares02@gmail.com [SMC Corporation, College Station, TX 77845 (United States); Rambabu, B. [Solid State Ionics and Surface Sciences Lab, Department of Physics, Southern University and A& M College, Baton Rouge, LA 70813 (United States); Kumari, Kusum [Department of Physics, National Institute of Technology, Warangal (India); Kalluru, Rajmohan R. [The University of Southern Mississippi, College of Science and Technology, 730 E Beach Blvd, Long Beach, MS 39560 (United States); Holze, Rudolf [Institut für Chemie, AG Elektrochemie, Technische Universität Chemnitz, D-09107 Chemnitz (Germany)

    2016-11-30

    Highlights: • LiCrTiO{sub 4} nanostructures were synthesized for electrochemical applications by soft chemical synthesis followed by annealing. • The presence of Cr and Ti elements are confirmed from the EDS spectrum. • Oxalic acid assisted LiCrTiO{sub 4} electrode shows higher specific capacity (mAh/g). - Abstract: Spinel LiCrTiO{sub 4} oxides to be used as electrode materials for a lithium ion battery and an asymmetric supercapacitor were synthesized using a soft-chemical method with and without chelating agents followed by calcination at 700 °C for 10 h. Structural and morphological properties were studied with powder X-ray diffraction, scanning electron and transmission electron microscopy. Particles of 50–10 nm in size are observed in the microscopic images. The presence of Cr and Ti is confirmed from the EDS spectrum. Electrochemical properties of LiCrTiO{sub 4} electrode were examined in a lithium ion battery. The electrode prepared with oxalic acid-assisted LiCrTiO{sub 4} shows higher specific capacity.This LiCrTiO{sub 4} is also used as anode material for an asymmetric hybrid supercapacitor. The cell exhibits a specific capacity of 65 mAh/g at 1 mA/cm{sup 2}. The specific capacity decreases with increasing current densities.

  15. Lithium Insertion in LiCr3O8, NaCr3O8, and KCr3O8 at Room Temperature and at 125°C

    DEFF Research Database (Denmark)

    Koksbang, R.; Fauteux, D.; Norby, P.

    1989-01-01

    Lithium insertion and deinsertion reactions have been carried out with LiCr3O8, NaCr3O8, and KCr3O8 chemically andelectrochemically at room temperature and at 125°C. The electrochemical experiments were performed with a nonaqueousliquid electrolyte at room temperature and with a polymer electroly...... is close to 4Li/NaCr3O8 and 1.3Li/KCr3O8.Lithium ion diffusion coefficients are similar for the two compounds in the comparable composition range.Thermally, the fully lithiated compounds appear to be as stable as the pristine materials.......Lithium insertion and deinsertion reactions have been carried out with LiCr3O8, NaCr3O8, and KCr3O8 chemically andelectrochemically at room temperature and at 125°C. The electrochemical experiments were performed with a nonaqueousliquid electrolyte at room temperature and with a polymer electrolyte....... At elevated temperatures, the isostructural compounds NaCr3O8 and KCr3O8 are able to accommodate morethan 4Li/MCr3O8. During this process, minor structural changes are observed. At room temperature, NaCr3O8 and KCr3O8also accommodate Li topotactically, but the maximum number of Li inserted per formula...

  16. Etching of fused silica fiber by metallic laser-induced backside wet etching technique

    Energy Technology Data Exchange (ETDEWEB)

    Vass, Cs., E-mail: vasscsaba@physx.u-szeged.hu [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dóm tér 9 (Hungary); Kiss, B.; Kopniczky, J.; Hopp, B. [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dóm tér 9 (Hungary)

    2013-08-01

    The tip of multimode fused silica fiber (core diameter: 550 μm) was etched by metallic laser-induced backside wet etching (M-LIBWE) method. Frequency doubled, Q-switched Nd:YAG laser (λ = 532 nm; τ{sub FWHM} = 8 ns) was used as laser source. The laser beam was coupled into the fiber by a fused silica lens with a focal length of 1500 mm. The other tip of the fiber was dipped into liquid gallium metallic absorber. The etching threshold fluence was measured to be 475 mJ/cm{sup 2}, while the highest fluence, which resulted etching without breaking the fiber, was 1060 mJ/cm{sup 2}. The progress of etching was followed by optical microscopy, and the etch rate was measured to be between 20 and 37 nm/pulse depending on the applied laser energy. The surface morphologies of the etched tips were studied by scanning electron microscopy. A possible application of the structured fibers was also tested.

  17. Etching of fused silica fiber by metallic laser-induced backside wet etching technique

    International Nuclear Information System (INIS)

    Vass, Cs.; Kiss, B.; Kopniczky, J.; Hopp, B.

    2013-01-01

    The tip of multimode fused silica fiber (core diameter: 550 μm) was etched by metallic laser-induced backside wet etching (M-LIBWE) method. Frequency doubled, Q-switched Nd:YAG laser (λ = 532 nm; τ FWHM = 8 ns) was used as laser source. The laser beam was coupled into the fiber by a fused silica lens with a focal length of 1500 mm. The other tip of the fiber was dipped into liquid gallium metallic absorber. The etching threshold fluence was measured to be 475 mJ/cm 2 , while the highest fluence, which resulted etching without breaking the fiber, was 1060 mJ/cm 2 . The progress of etching was followed by optical microscopy, and the etch rate was measured to be between 20 and 37 nm/pulse depending on the applied laser energy. The surface morphologies of the etched tips were studied by scanning electron microscopy. A possible application of the structured fibers was also tested.

  18. Plasma etching of patterned tungsten

    International Nuclear Information System (INIS)

    Franssila, S.

    1993-01-01

    Plasma etching of tungsten is discussed from the viewpoint of thin film structure and integrated circuit process engineering. The emphasis is on patterned tungsten etching for silicon device and X-ray mask fabrication. After introducing tungsten etch chemistries and mechanisms, microstructural aspects of tungsten films (crystal structure, grain size, film density, defects, impurities) in relation to etching are discussed. Approaches to etch process optimization are presented, and the current state-of-the-art of patterned tungsten etching is reviewed. (orig.)

  19. DC-pulsed voltage electrochemical method based on duty cycle self-control for producing TERS gold tips

    International Nuclear Information System (INIS)

    Vasilchenko, V E; Kharintsev, S S; Salakhov, M Kh

    2013-01-01

    This paper presents a modified dc-pulsed low voltage electrochemical method in which a duty cycle is self tuned while etching. A higher yield of gold tips suitable for performing tip-enhanced Raman scattering (TERS) measurements is demonstrated. The improvement is caused by the self-control of the etching rate along the full surface of the tip. A capability of the gold tips to enhance a Raman signal is exemplified by TERS spectroscopy of single walled carbon nanotubes bundle, sulfur and vanadium oxide

  20. Characteristics of diallyl phthalate resin as a fission track detector

    CERN Document Server

    Tsuruta, T

    1999-01-01

    Diallyl phthalate (DAP) resin plates were irradiated with fission fragments, and then etched in aqueous solution of KOH. Etched tracks were observed and counted by using an optical microscope. The detection efficiency of fission fragments was about 100% for both perpendicular and random incidence. DAP plates were insensitive to alpha particles and fast neutrons. These characteristics are suitable for detecting selected fission fragments, which coexist with alpha particles or fast neutrons. DAP plates are valuable for quantitative analysis of fissionable materials and neutron dosimetry. DAP and allyl diglycol carbonate (CR-39) were formed into copolymers in various ratios. The copolymers showed intermediate characteristics between DAP and CR-39. The fabrication of the copolymers made it possible to control the discrimination level for detection of heavy charged particles.