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Sample records for biomonitoring technique neutron

  1. Study on air pollution around China's largest oil refinery complex using multielements in biomonitors and neutron activation analysis techniques

    International Nuclear Information System (INIS)

    Three different kinds of plant leaves, Chinese white poplar, arborvitae and pine needle have been sampled from different places, Yanshan Oil refinery complex, Capital Iron and Steel Factory and Badachu, a control place in Beijing, as bio-monitors for air pollution studies. Each sample was divided into two parts, washed and unwashed, 31 trace elements, As, Au, Br, Ca, Cd, K, La, Lu, Mo, Na, Sb, Sm, U, W, Yb, Ba, Ce, Co, Cr, Cs, Eu, Fe, Hf, Hg, Rb, Sc, Se, Sr, Ta, Tb, Th and Zn have been determined by using KO method of instrument neutron activation analysis techniques with a long irradiation in the 15MW Heave Water Research Reactor, China Institute of Atomic Energy. The results indicated that: 1) the concentration of trace elements in unwashed samples are much higher than that in washed samples; 2) the area of capital iron and steel factory is polluted heavily, and Yanshan oil refinery complex area is polluted moderately, 3) All the three kinds of plant leaves can be used as air pollution biomonitors, because they can absorb some trace elements from the air pollutants. Aspen is good for monitoring in particular seasons and Pine needle is better than arborvitae for yearly monitoring; 4) Elements of As, Cd, Hg, Co, Rb, Sb, W and Zn are highly absorbed by Chinese white poplar. Pine needle is sensitive to absorb the elements of Br, Cr, Cd, Fe, Sc, Cs and rear earth elements, but arborvitae is very sensitive for the absorption of Sr. (author)

  2. Air pollution biomonitoring in Argentina, application of neutron activation analysis to the study of biomonitors

    International Nuclear Information System (INIS)

    The assessment of baseline levels of atmospheric pollutants and the identification of polluted areas is a complex problem, as pollutant contents at a certain geographical location is usually a combination of contributions from various diverse sources, including long-range transport. Elemental chemical characterization of atmospheric pollutants is thus of great importance and Neutron Activation Analysis has proved to be a powerful technique for multielemental determination of trace elements in biomonitors and aerosols. The general objective of this project is to study the use of biomonitors, specially lichens, for evaluating pollutant levels over a wide geographic area of Argentina and for establishing baseline values and assessing time trends. Two lichen species (Usnea sp. and Ramalina ecklonii (Spreng.) Mey. and Flot) have been identified as suitable monitors of air pollution, with potential regional application at the central area of the country (province of Cordoba) and pilot studies have been initiated to test the practicability of sampling and sample collection. An area of approximately 40,000 km2 will be covered by a sampling network, using in situ growing lichens. The distribution maps for the two selected species are already drawn and sampling of local soils will also be conducted. Current efforts at the Neutron Activation Analysis laboratory are put on assessing, for the selected lichen species, the influence of sample preparation methods on trace element concentrations. The use of other analytical techniques will allow the evaluation of the bioindicator chemical response and its relationship to different atmospheric quality levels. Source identification and apportionment will be done by statistical fingerprinting of the elemental concentrations, as sources of pollution are characterized by being composed of different mixtures of elements in different proportions. In this way and as a long-term objective, regional maps will be drawn showing the

  3. Atmospheric deposition of rare earth elements in Albania studied by the moss biomonitoring technique, neutron activation analysis and GIS technology.

    Science.gov (United States)

    Allajbeu, Sh; Yushin, N S; Qarri, F; Duliu, O G; Lazo, P; Frontasyeva, M V

    2016-07-01

    Rare earth elements (REEs) are typically conservative elements that are scarcely derived from anthropogenic sources. The mobilization of REEs in the environment requires the monitoring of these elements in environmental matrices, in which they are present at trace level. The determination of 11 REEs in carpet-forming moss species (Hypnum cupressiforme) collected from 44 sampling sites over the whole territory of the country were done by using epithermal neutron activation analysis (ENAA) at IBR-2 fast pulsed reactor in Dubna. This paper is focused on REEs (lanthanides) and Sc. Fe as typical consistent element and Th that appeared good correlations between the elements of lanthanides are included in this paper. Th, Sc, and REEs were never previously determined in the air deposition of Albania. Descriptive statistics were used for data treatment using MINITAB 17 software package. The median values of the elements under investigation were compared with those of the neighboring countries such as Bulgaria, Macedonia, Romania, and Serbia, as well as Norway which is selected as a clean area. Geographical distribution maps of the elements over the sampled territory were constructed using geographic information system (GIS) technology. Geochemical behavior of REEs in moss samples has been studied by using the ternary diagram of Sc-La-Th, Spider diagrams and multivariate analysis. It was revealed that the accumulation of REEs in current mosses is associated with the wind-blowing metal-enriched soils that is pointed out as the main emitting factor of the elements under investigation. PMID:27044293

  4. Assessment of atmospheric deposition of heavy metals and other elements in Belgrade using the moss biomonitoring technique and neutron activation analysis

    International Nuclear Information System (INIS)

    The study aimed at assessing atmospheric deposition of heavy metals and other elements using the moss genera Brachythecium sp. (B. rutabulum and B. salebrosum) and Eurhynchium sp. (E. hians and E. striatum) collected in autumn 2004 in the urban area of Belgrade. The concentrations of 36 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Br, Rb, Sr, Mo, Sb, I, Cs, Ba, La, Ce, Sm, Tb, Dy, Hf, Ta, W, Hg, Th, U) were determined in moss and local topsoil samples by instrumental neutron activation analysis. The concentration of elements in moss positively correlated to those obtained for topsoil. High enrichment factors for As, Zn, Mo, Br, Sb, Se, Hg, and Cl, calculated to continental crust composition, gave an evidence for anthropogenic impact on urban area, mainly due to intensive vehicular traffic and fossil fuel combustion. The concentrations of elements in moss, characteristic for fossil fuel combustion, obtained in this study, were substantially lower than in the previous investigation (2000) conducted in the area of Belgrade. The level of concentrations for V, Cr, Ni, and As in moss from this study correlated to those measured for neighboring countries, and were several times higher than the base-level data from low polluted areas. The level of accumulated elements in both investigated moss genera were similar and all studied species could be combined for biomonitoring purposes in urban areas

  5. The role of neutron activation analysis in nutritional biomonitoring programs

    International Nuclear Information System (INIS)

    Nutritional biomonitoring is a multidisciplinary task and an integral part of a more general bioenvironmental surveillance. In its comprehensive form, it is a combination of biological, environmental, and nutrient monitoring activities. Nutrient monitoring evaluates the input of essential nutrients required to maintain vital bodily functions; this includes vigilance over extreme fluctuations of nutrient intake in relation to the recommended dietary allowances and estimated safe and adequate daily dietary intakes and adherence to the goals of provisional tolerance limits. Environmental monitoring assesses the external human exposure via ambient pathways, namely, air, water, soil, food, etc. Biological monitoring quantifies a toxic agent and its metabolites in representative biologic specimens of an exposed organ to identify health effects. In practice, coordinating all three components of a nutritional biomonitoring program is complex, expensive, and tedious. Experience gained from the US National Health and Nutrition Examination Surveys demonstrates the problems involved. By far the most critical challenge faced here is the question of analytical quality control, particularly when trace element determinations are involved. Yet, measures to ensure reliability of analytical data are mandatory, and there are no short-cuts to this requirement. The purpose of this presentation is to elucidate the potential of neutron activation analysis (NAA) in nutritional biomonitoring activities

  6. Biomonitors for pollution assay using nuclear techniques

    International Nuclear Information System (INIS)

    Mosses are multicellular, chlorophyll bearing plants, which are not complex but have a highly developed reproductive system. They occur in damp conditions, such as in woods and also on walls. The stems contain a central core of elongated membrane. The intricate branching system with many leaves provides large surface area on which particles can be trapped. This structure means that mosses can accumulate airborne pollutants. In India most of the air pollution studies so for been based on atmospheric aerosols collected on air particulate matters. In the present study an attempt has been made to see the feasibility of mosses to be used as a biomonitors for air pollution studies in Mumbai

  7. Atmospheric deposition of trace elements around Ulan Bator city studied by moss and lichen biomonitoring technique and INAA

    International Nuclear Information System (INIS)

    For the first time the moss and lichen biomonitoring technique has been applied to air pollution in Mongolia (Ulan-Bator, the capital city). INAA at the IBR-2 reactor has made it possible to determine the content of 35 elements in moss and lichen biomonitors. Samples collected at sites located 10-15 km from the center of Ulan-Bator were analyzed by Instrumental Neutron Activation Analysis (INAA) using epithermal neutrons. The mosses (Rhytidium rugosum, Thuidium abietinum, Entodon concinnus) and lichens (Cladonia stellaris, Parmelia separata) were used to study the atmospheric deposition of trace elements. It was shown that the suggested types of mosses could be used as suitable biomonitors to estimate the concentration levels of heavy metals and trace elements in Ulan-Bator atmospheric deposition. The results are compared to the data of atmospheric deposition of some European countries

  8. Atmospheric Deposition of Trace Elements Around Ulan-Bator City Studied by Moss and Lichen Biomonitoring Technique and INAA

    CERN Document Server

    Ganbold, G; Gundorina, S F; Frontasyeva, M V; Ostrovnaya, T M; Pavlov, S S; Tsendeekhuu, T

    2005-01-01

    For the first time the moss and lichen biomonitoring technique has been applied to air pollution in Mongolia (Ulan-Bator, the capital city). INAA at the IBR-2 reactor has made it possible to determine the content of 35 elements in moss and lichen biomonitors. Samples collected at sites located 10-15 km from the center of Ulan-Bator were analyzed by Instrumental Neutron Activation Analysis (INAA) using epithermal neutrons. The mosses (\\textit{Rhytidium rugosum}, \\textit{Thuidium abietinum}, \\textit{Entodon concinnus}) and lichens (\\textit{Cladonia stellaris}, \\textit{Parmelia separata}) were used to study the atmospheric deposition of trace elements. It was shown that the suggested types of mosses could be used as suitable biomonitors to estimate the concentration levels of heavy metals and trace elements in Ulan-Bator atmospheric deposition. The results are compared to the data of atmospheric deposition of some European countries.

  9. Air Pollution with Heavy Metals and Radionuclides in Slovakia Studied by the Moss Biomonitoring Technique

    CERN Document Server

    Florek, M; Mankovska, B; Oprea, K; Pavlov, S S; Steinnes, E; Sykora, I

    2001-01-01

    Applying the moss biomonitoring technique to air pollution studies in Slovakia, heavy metals, rare-earth elements, actinides (U and Th) were determined in 86 moss samples from the European moss survey 2000 by means of epithermal neutron activation analysis at the IBR-2 reactor (Dubna). Such elements as In, Cu, Cd, Hg and Pb were determined by AAS in the Forest Research Institute, Zvolen (Slovakia). The results of measurement of the natural radionuclides ^{210}Pb, ^{7}Be, ^{137}Cs and ^{40}K in 11 samples of moss are also reported. A comparison with the results from moss surveys 1991 and 1995 revealed previously unknown tendencies of air pollution in the examined areas.

  10. Biomonitoring of nitrogen pollution. Possibilities and limitations of bioindication techniques; Biomonitoring von Stickstoffimmissionen. Moeglichkeiten und Grenzen von Bioindikationsverfahren

    Energy Technology Data Exchange (ETDEWEB)

    Mohr, K. [Landwirtschaftskammer Niedersachsen, Oldenburg (Germany)

    2007-10-15

    Background and aim. Air pollution caused by oxidized and reduced nitrogen is distributed over wide areas of Europe at a high level. As an alternative or complement to physical measurements and modelling calculations, biomonitoring with plants provides techniques to assess amounts and effects of pollution from oxidized and reduced nitrogen compounds (depositions and concentrations). Many of the previously implemented techniques are based on well-proven standardised methods, e.g. documented in VDI guidelines, modified more or less for a biomonitoring of atmospheric nitrogen pollution. This paper gives a review of the techniques for a biomonitoring of atmospheric nitrogen pollution, their possibilities as well as their limitations. Main features - diversity of the ground vegetation - nitrogen accumulation in vascular plants - exposure of vascular plants - mapping of epiphytic lichens, bryophytes and algae - nitrogen accumulation in lichens and bryophytes - exposure of lichens and bryophytes. Results and Discussion. Important response parameters are nitrogen concentrations in plant tissue (shoot, needle, leave) and biodiversity of plant species. These responses of vascular plants in many cases are influenced by other local varying conditions, in particular the soil. The exposure of vascular plants over a short period provides a standardised quantification of the total atmospheric nitrogen input in a model ecosystem. The enrichment of nitrogen in the plant tissue of bryophytes and lichens from the ground vegetation is closely correlated with the amount of nitrogen deposition. The diversity of epiphytic lichens and the response of exposed Hypogymnia physodes is more sensitive to ammonia than to nitrous oxide, whereas with the diversity of epiphytic bryophytes or the abundance of algae no significant correlation with atmospheric N pollution were found. Conclusions. Some bioindication techniques provide a cause-effect related, partly standardised biomonitoring of nitrogen

  11. Atmospheric deposition of heavy metals around the lead and copper-zinc smelters in Baia Mare, Romania, studied by the moss biomonitoring technique, neutron activation analysis and flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    The mosses Pleurozium schreberi, Pseudoscleropodium purum and Rhytidiadelphus squarrosus were used as biomonitors to study the atmospheric deposition of metals around the lead and copper-zinc smelters in Baia Mare. Samples representing the last three years' growth of moss or its green part, collected on the ground at 28 sites located 2-17 km from the source area, were analyzed by instrumental neutron activation analysis using epithermal neutrons (ENAA) and by flame atomic absorption spectrometry (FAAS). A total of 31 elements were determined, including most of the heavy metals characteristic of emissions from this kind of industry. The observed data for Pb, As, Cu, and Cd are all high compared with those observed in other regions of Europe with similar industries, but the concentrations in moss approach regional background levels at a distance of about 8 km from the main source area. Factor analysis of the data distinguishes two industrial components, one characterized by Pb, Cu, As, and Sb, and another one by Zn and Cd. A strong crustal component including five major elements (Na, Mg, Al, Ti, Fe) and an additional number of trace elements (Sc, V, Cr, Cs, Ba, REE, Th) also appears to be derived mainly from industrial sources. The mean I value in the present material is 5 times lower than the corresponding level in moss in Norway, and also consistently lower than elsewhere in Europe, a fact which evidences the endemic character of the examined area due to iodine depletion. (author)

  12. Atmospheric deposition of heavy metals around the lead and copper-zinc smelters in Baia Mare, Romania, studied by the moss biomonitoring technique, neutron activation analysis and flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    The mosses Pleurozium schreberi, Pseudoscleropodium purum and Rhytidiadelphus squarrosus were used as biomonitors to study the atmospheric deposition of heavy metals around the lead and copper-zinc smelters in Baia Mare. Samples representing the last three year's growth of moss or its green part, collected on the ground at 28 sites located 2-17 km from the source area, were analyzed by instrumental neutron activation analysis using epithermal neutrons and by flame atomic absorption spectrometry. A total of 31 elements were determined, including most of the heavy metals characteristic of emissions from this kind industry. The observed data for Pb, As, Cu, and Cd are all high compared with those observed in other regions of Europe with similar industries, but the concentrations in moss approach regional background levels at a distance of about 8 km from the main source area. Factor analysis of the data distinguishes two industrial components, one characterized by Pb, Cu, As, and Sb, and another one by Zn and Cd. A strong crustal component including five major elements (Na, Mg, Al, Ti, Fe) and an additional number of trace elements (Sc, V, Cr, Cs, Ba, REE, Th) also appears to be derived mainly from industrial sources. The mean I value in the present material is 5 times lower than the corresponding level in moss in Norway, and also consistently lower than elsewhere in Europe, a fact which evidence the endemic character of the examined area due to iodine depletion

  13. Atmospheric Deposition of Heavy Metals around the Lead and Copper-Zinc Smelters in Baia Mare, Romania, Studied by the Moss Biomonitoring Technique, Neutron Activation Analysis and Flame Atomic Absorption Spectrometry

    CERN Document Server

    Culicov, O A; Steinnes, E; Okina, O S; Santa, Z; Todoran, R

    2002-01-01

    The mosses Pleurozium schreberi, Pseudoscleropodium purum and Rhytidiadelphus squarrosus were used as biomonitors to study the atmospheric deposition of heavy metals around the lead and copper-zinc smelters in Baia Mare. Samples representing the last three years' growth of moss or its green part, collected on the ground at 28 sites located 2-17 km from the source area, were analyzed by instrumental neutron activation analysis using epithermal neutrons and by flame atomic absorption spectrometry. A total of 31 elements were determined, including most of the heavy metals characteristic of emissions from this kind industry. The observed data for Pb, As, Cu, and Cd are all high compared with those observed in other regions of Europe with similar industries, but the concentrations in moss approach regional background levels at a distance of about 8 km from the main source area. Factor analysis of the data distinguishes two industrial components, one characterized by Pb, Cu, As, and Sb, and another one by Zn and Cd...

  14. Air pollution biomonitoring in Argentina, application of neutron activation analysis to the study of biomonitors

    International Nuclear Information System (INIS)

    Due to low population density, total air pollutant emissions in Argentina are still low if compared with highly industrialised countries. Although a significant deterioration of air quality has been observed for a long time, air monitoring did not begin until the 90's and only in a few cities. The use of air pollution biomonitors represents an important contribution to Argentina, as measurements of air pollutants in large areas would require especial technical equipment not easily available and operated. In this project, two lichen species (Ramalina ecklonii (Spreng) Mey and Flot and Usnea amblyoclada (Muell. Rg.) Zahlbr.) and a Bromeliaceae (Tillandsia capillaris) are used as biomonitors of air pollution at a 50, 000 km2 area in Cordoba province (central Argentina). AAS and INAA have been applied for the analysis of samples, determining As, Ba, Br, Ce, Co, Cr, Cs, Cu, Eu, Fe, Hf, Gd, K, La, Lu, Mn, Na, Ni, Pb, Rb, Sb, Sc, Sm, Ta, Tb, Th, U, Yb and Zn. The following physiological parameters were also determined: chlorophyll a, chloropyll b, phaeophytin a, phaeophytin b, hydroperoxy conjugated dienes, malonaldehide and sulphur. Some of these parameters were used for calculating a pollution index. These determinations were carried out on pools collected at the sampling sites. AAS and physiological parameters were also applied to the analysis of five-replicate samples in order to study variability sources. For data evaluation, different statistical and other evaluating tools were used: descriptive statistics and Spearman's correlation analysis were used on data from the three biomonitor species while factor analysis and mapping, only for R. ecklonii results. (author)

  15. Heavy Metals and Trace Elements Atmospheric Deposition Studies in Tula Region Using Moss Biomonitors Technique

    CERN Document Server

    Ermakova, E V; Steinnes, E

    2002-01-01

    For the first time the moss biomonitors technique was used in air pollution studies in Tula Region (Central Russia), applying NAA, AAS. Moss samples were collected at 83 sites in accordance with the sampling strategy adopted in European projects on biomonitoring atmospheric deposition. A wide set of trace elements in mosses was determined. The method of epithermal neutron activation at IBR-2 reactor of FLNP JINR has made it possible to identify 33 elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Zn, As, Br, Rb, Sr, Mo, Sb, I, Cs, Ba, La, Ce, Sm, Tb, Yb, Hf, Ta, W, Th, U) in the large-scale concentration range - from 10000 ppm for K to 0,001 ppm for Tb and Ta. Cu, Cd and Pb were determined by the flame AAS in the Norwegian Institute of Science and Technology. Using the graphical technique and principal component analysis allowed to separate plant, crustal and general pollution components in the moss. The obtained data will be used for constructing coloured maps of the distribution of elements over t...

  16. Instrumental neutron activation analysis and inductively coupled plasma mass spectrometry on atmospheric biomonitors

    International Nuclear Information System (INIS)

    In a biomonitoring study aiming to find alternatives to lower epiphytes as air-quality monitors, lichens and tree bark were exposed at different sites for discontinuous periods of 2 months and continuously. Native lichens were collected as well. The contents for 22 elements were obtained by both instrumental neutron activation analysis (INAA) and inductively coupled plasma mass spectrometry (ICP-MS). Quality control as asserted by analyzing ISE-921, NIST-1547 and TL-1 was good. Losses of As and Se by volatilization during sample digestion and neutron irradiation were evident; Ca contents by ICP-MS appeared underestimated probably due to the formation of the insoluble fluoride. ICP-MS featured a better precision than INAA. Nonparametric statistics were applied to the ICP-MS replicates, to those determined by INAA, and to compare the results of both techniques. High or even excellent correlations were found between replicates in INAA, whereas, in ICP-MS, Cr and Ta were just fairly or not correlated. As an overall comparison of the techniques, biased results were found for As, Ba, Ce, Cr, Cs, Hf, La, Sc, Se, Ta, and Zn; unbiased results could be found for Ca, Co, Fe, K, Na, Rb, Sb, Sm, Tb, Th, and U. (author)

  17. Air Pollution Studies in Central Russia (Tula Region) Using Moss Biomonitoring Technique, NAA and AAS

    CERN Document Server

    Ermakova, E V; Steinnes, E

    2002-01-01

    For the first time the moss biomonitoring technique has been applied to air pollution monitoring in Central Russia (Tula Region). Moss samples were collected from 83 sites in accordance with the sampling strategy of European projects on biomonitoring of atmospheric deposition. Neutron activation analysis (NAA) at the IBR-2 reactor has made it possible to determine the concentration of 33 elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Zn, As, Br, Rb, Sr, Mo, Sb, I, Cs, Ba, La, Ce, Sm, Tb, Yb, Hf, Ta, W, Th, U) over a large concentration range (from 10000 mg/kg for K to 0.001 mg/kg for Tb and Ta). In addition to NAA, flame AAS (atomic absorption spectrometry) was applied to determine the concentration of Cd, Cu and Pb. Factor analysis was applied to determine possible sources of elements detected in the investigated mosses. Eight factors were identified. The geographical distribution of factor scores is presented. The interpretation of the factor analysis findings points to natural as well as anthr...

  18. Air pollution studies in Macedonia using the moss biomonitoring technique, NAA, AAS and GIS technology

    International Nuclear Information System (INIS)

    For the first time the moss biomonitoring technique was applied to air pollution studies in the Republic of Macedonia, in the central part of the Balkan Peninsula. Samples of the terrestrial mosses Hypnum cupressiforme, Campothecium lutescens, and Homolothecium sericium were collected in September-October 2002 in accordance with the sampling strategy of the European moss survey programme. The sampling network included 73 sites evenly distributed over the territory of the country. A total of 43 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Zr, Mo, Ag, Cd, In, Sb, I, Cs, Ba, La, Ce, Sm, Eu, Tb, Hf, Ta, W, Au, Hg, Pb, Th, and U) were determined by instrumental epithermal neutron activation analysis and flame

  19. Neutron techniques in Safeguards

    International Nuclear Information System (INIS)

    An essential part of Safeguards is the ability to quantitatively and nondestructively assay those materials with special neutron-interactive properties involved in nuclear industrial or military technology. Neutron techniques have furnished most of the important ways of assaying such materials, which is no surprise since the neutronic properties are what characterizes them. The techniques employed rely on a wide selection of the many methods of neutron generation, detection, and data analysis that have been developed for neutron physics and nuclear science in general

  20. Neutron visual sensing technique

    International Nuclear Information System (INIS)

    The neutron visual sensing technique is a technology to extract physical quantities from the information on inner structures of complex materials or machineries which have been visualized and recorded by using neutron beams. Research and utilization of this technique is now under worldwide development since it can provide the information that is not possible by X-ray radiography. We show how to use stationary neutron sources (Research reactors) in chapter 2, and how to utilize pulsed neutron source (Japan Proton Accelerator Complex, J-PARC). Also the production of micro-element analyzer by an enterprise using the knowledge on radiological equipment is described as an example. (author)

  1. Atmospheric Deposition of Heavy Metals in Serbia Studied by Moss Biomonitoring, Neutron Activation Analysis and GIS Technology

    CERN Document Server

    Frontasyeva, M V; Kumar, M; Matavuly, M; Pavlov, S S; Radnovic, D; Steinnes, E

    2002-01-01

    The results of a pilot study on atmospheric deposition of heavy metals and other trace elements using the moss biomonitoring technique in the northern part of Serbia and some areas of Bosnia are presented. Samples of Hypnum cupressiforme along with some other moss types were collected at 92 sites during the summer of 2000. A total of 44 elements were determined by instrumental neutron activation analysis using epithermal neutrons. The observed levels of Cu, Zn, As, Ag, Cd, In, Sb, etc. in the area surrounding the town of Bor (Serbia) are comparable to those reported from similar industrial areas in other countries such as the Copper Basin in Poland and the South Urals of Russia. In the same region the maximum Se and Mo concentrations are the highest ever recorded in biomonitoring studies using mosses. High median concentrations of Fe and Ni in Serbian mosses are associated with a crustal component as apparent from factor analysis of the moss data. This component could be a result of windblown soil dust (most ...

  2. The use of biomonitors and neutron activation analysis in the study of air pollution of Buenos Aires city

    International Nuclear Information System (INIS)

    Biomonitors were used as part of a pollution study of Buenos Aires city atmosphere under the International Atomic Energy Agency Research Contract ARG 7251, from the Co-ordinated Research Programme on Applied Research on Air Pollution using Nuclear Related Analytical Techniques. Lichens were primarily selected as indicators. Two different approaches were conducted, direct sampling of Parmotrema reticulatum, at a few places and the use of lichen bags, filled with Usnea sulcata from a northern national park, and hung at different sites. Simultaneously, tree bark was tried as biomonitor. Platanus acerifolia and Melia azedarach were selected as candidates, for being the most common trees in the city, but only P. acerifolia was analyzed. All the samples were analyzed using instrumental neutron activation analysis at the Ezeiza Atomic Centre of the National Atomic Energy Commission. RA-3) reactor was used for the irradiations, determining: As, Ba, Br, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Rb, Sb, Sc, Sm, Ta, Tb, Th, U, Yb and Zn. Concentration values for P. reticulatum compared well with values from literature. For U. sulcata differences were found among the tested sites and also, for some elements an increasing trend with time was observed. Enrichment factors calculated using Sc as reference and Mason's crustal average concentrations showed vehicules and refuse incineration as contributing sources to the aerosol. Tree bark from Buenos Aires and from a smaller city with mainly agricultural activities were analyzed and the results are coincident with those from lichens. This work is the first and preliminar contribution to the study of Buenos Aires aerosol using biomonitors. (author)

  3. Multi-element atmospheric deposition in Macedonia studied by the moss biomonitoring technique.

    Science.gov (United States)

    Barandovski, Lambe; Frontasyeva, Marina V; Stafilov, Trajče; Šajn, Robert; Ostrovnaya, Tatyana M

    2015-10-01

    Moss biomonitoring technique using moss species Homolothecium lutescens (Hedw.) Robins and Hypnum cupressiforme (Hedw.) was applied to air pollution studies in the Republic of Macedonia. The study was performed in the framework of the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops under the auspices of the United Nations Economic Commission for Europe (UNECE) Convention on Long-Range Transboundary Air Pollution (LRTAP). The presence of 47 elements was determined by instrumental epithermal neutron activation analysis, atomic absorption spectrometry and atomic emission spectrometry with inductively coupled plasma. Normality of the datasets of elements was investigated, and Box-Cox transformation was used in order to achieve normal distributions of the data. Different pollution sources were identified and characterized using principal component analysis (PCA). Distribution maps were prepared to point out the regions most affected by pollution and to relate this to the known sources of contamination. The cities of Veles, Skopje, Tetovo, Radoviš and Kavadarci were determined to experience particular environmental stress. Moreover, three reactivated lead-zinc mines were also shown to contribute to a high content of lead and zinc in the eastern part of the country. However, a comparison with the previous moss survey conducted in 2005 showed a decreasing trend of pollution elements that are usually associated with emission from industrial activities. PMID:26062458

  4. Neutron radiography, techniques and applications

    International Nuclear Information System (INIS)

    After describing the principles of the ''in pool'' and ''dry'' installations, techniques used in neutron radiography are reviewed. Use of converter foils with silver halide films for the direct and transfer methods is described. Advantages of the use of nitrocellulose film for radiographying radioactive objects are discussed. Dynamic imaging is shortly reviewed. Standardization in the field of neutron radiography (ASTM and Euratom Neutron Radiography Working Group) is described. The paper reviews main fields of use of neutron radiography. Possibilities of use of neutron radiography at research reactors in various scientific, industrial and other fields are mentioned. Examples are given of application of neutron radiography in industry and the nuclear field. (author)

  5. New techniques in neutron scattering

    International Nuclear Information System (INIS)

    New neutron sources being planned, such as the Advanced Neutron Source (ANS) or the European Spallation Source (ESS), will provide an order of magnitude flux increase over what is available today, but neutron scattering will still remain a signal-limited technique. At the same time, the development of new materials, such as polymer and ceramic composites or a variety of complex fluids, will increasingly require neutron-based research. This paper will discuss some of the new techniques which will allow us to make better use of the available neutrons, either through improved instrumentation or through sample manipulation. Discussion will center primarily on unpolarized neutron techniques since polarized neutrons will be the subject of the next paper. (author)

  6. A graphical technique for distinguishing plant material and soil from atmospheric deposition in biomonitors

    International Nuclear Information System (INIS)

    The paper explores the limits to which a new graphical technique can distinguish the various hierarchical levels of sources of trace elements within biomonitors. When applied to data from Portuguese lichens, it appears to resolve four levels of sources, from plant material down to individual types of pollution. Careful factor analysis appears to offer very similar results, being weaker than the graphical method in some aspects and stronger in others. As a result, it now seems possible to determine sources for elements in lichens with better precision and confidence than was available previously. (author)

  7. Neutron activation analysis of atmospheric biomonitors from the Azores. A comparative study of lower and higher plants

    International Nuclear Information System (INIS)

    Within an extensive survey of lower and higher plants in the Azores' Terceira and Santa Maria islands, this study is focused on the evaluation of ectohydric bryophytes and bark from Cryptomeria japonica as an alternative to epiphytic lichens for air-monitoring purposes. Neutron activation analysis (k0-NAA) has been applied to all field samples for elemental determinations. Judging from the present results, and since the islands embody most features of the whole archipelago, bryophytes do not appear as an option for further campaigns in the Azores, due to scanty supply and relatively poor performance as biomonitors. On the other hand, comparisons of bark with lichens collected at the same sites seem fairly good, and elements are enriched in bark to an even greater extent than in lichens. All things considered - including material availability and ecological concern - bark stands for a sensible choice for biomonitoring in the Azores. (author)

  8. Neutron optics requirements for neutron imaging techniques

    International Nuclear Information System (INIS)

    The utilization of X-rays for material research is common in many respects since their discovery at the end of the 19th century. New sources as electron synchrotrons or free-electron lasers push the methodology and the application ranges further. A similar approach started 50 years later with neutrons when sources with reasonable high intensity became available. Today, there are many similarities and complementarities visible between X-ray and neutron studies and the involved techniques. Therefore, it is worth to compare and to adapt from the advanced X-ray techniques and to translate it into the neutron world. Despite of the lack of neutron intensities compared to the most brilliant X-ray beams, the specific properties of neutrons (contrast, spin, magnetic moment, penetration power) are utilized and they will further play an important role in non-invasive studies on the micro- and macro scale. This paper wants to encourage to 'look over the fence' into activities of the X-ray community as currently running in the COST action MP-1203.

  9. Experimental technique of neutron reflection

    International Nuclear Information System (INIS)

    It is presented that the classifications, structures and components of neutron reflectometer (NR), as well s functions and parameters of each components, detailed characters of NR facility 'PRN-2M'. Based on the practical experiments, the basic experimental techniques, the measurement and the related experimental settings are described, including the choice of experimental conditions, adjustments of polarized neutron beam line, basic experimental technique and approach of measurement. The above can be an instruction for NR experiments and a reference for NR construction. (authors)

  10. Determination of I-129 in biomonitors collected in the vicinity of a nuclear power plant by neutron activation analysis

    Czech Academy of Sciences Publication Activity Database

    Krausová, Ivana; Kučera, Jan; Světlík, Ivo

    2013-01-01

    Roč. 295, č. 3 (2013), s. 2043-2048. ISSN 0236-5731 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : I-129 * biomonitor * Thyroid gland * neutron activation analysis * nucelar power plant Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.415, year: 2013 http://link.springer.com/content/pdf/10.1007%2Fs10967-012-2200-5

  11. Determination of 129 I in biomonitors collected in the vicinity of a nuclear power plant by neutron activation analysis

    Czech Academy of Sciences Publication Activity Database

    Krausová, Ivana; Kučera, Jan; Světlík, Ivo

    2012-01-01

    Roč. 293, 13Sep2012 (2012), s. 1-6. ISSN 1588-2780 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : Iodine-129 * neutron activation analysis * biomonitor * nuclear power plant * Thyroid gland Subject RIV: CB - Analytical Chemistry, Separation http://download.springer.com/static/pdf/725/art%253A10.1007%252Fs10967-012-2200-5.pdf?auth66=1361263915_42267d28376ca81c4fc0de53c3cb59f4&ext=.pdf

  12. New Techniques in Neutron Scattering

    DEFF Research Database (Denmark)

    Birk, Jonas Okkels

    Neutron scattering is an important experimental technique in amongst others solid state physics, biophysics, and engineering. This year construction of European Spallation Source (ESS) was commenced in Lund, Sweeden. The facility will use a new long pulsed source principle to obtain higher...... potential performance than any existing facility, however in order to use this pulse structure optimally many existing neutron scattering instruments will need to be redesigned. This defense will concentrate on the design and optimization of the inverse time-of-flight cold neutron spectrometer CAMEA. The...... unprecedented large fraction of neutrons scattered in the horizontal plane. Together with the ESS source this will produce an instrument that promises several orders of magnitude higher performance than the best currently existing neutron spectrometers. The design of CAMEA involved kinematic calculations...

  13. Biomonitoring of occupational exposure: Neutron activation determination of selected metals in the body tissues and fluids of workers manufacturing stainless steel vessels

    Czech Academy of Sciences Publication Activity Database

    Kučera, Jan; Bencko, V.; Tejral, J.; Borská, L.; Soukal, L.; Řanda, Zdeněk

    2004-01-01

    Roč. 259, č. 1 (2004), s. 7-11. ISSN 0236-5731 R&D Projects: GA AV ČR KSK4055109 Institutional research plan: CEZ:AV0Z1048901 Keywords : occupational exposure * biomonitoring * neutron activation analysis Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 0.457, year: 2004

  14. Fusion Based Neutron Sources for Security Applications: Neutron Techniques

    OpenAIRE

    Albright, S.; Seviour, Rebecca

    2014-01-01

    The current reliance on X-Rays and intelligence for na- tional security is insufficient to combat the current risks of smuggling and terrorism seen on an international level. There are a range of neutron based security techniques which have the potential to dramatically improve national security. Neutron techniques can be broadly grouped into neutron in/neutron out and neutron in/photon out tech- niques. The use of accelerator based fusion devices will potentially enable to wide spread applic...

  15. Biomonitoring of air pollution in Jamaica through trace-element analysis of epiphytic plants using nuclear and related analytical techniques

    International Nuclear Information System (INIS)

    The main goal of the Coordinated Research Project (No:9937/R0), entitled 'Biomonitoring of Air Pollution in Jamaica Through Trace-Element Analysis of Epiphytic Plants Using Nuclear and Related Analytical Techniques', is to identify and validate site specific epiphytic plants for biomonitoring the atmospheric pollution in Jamaica using nuclear analytical techniques at the International Centre for Environmental and Nuclear Sciences (ICENS). The specific objectives for the second year of the project were: Development of HOP for sampling epiphytic plants in Jamaica; Sampling design and sample collection; Sample preparation and analysis; Development of an in-house SRM and participation in the NAT-5 inter-laboratory study; Data analysis and interpretation of the results; Development of a work plan of the third year of the project

  16. Neutron techniques for cultural heritage

    International Nuclear Information System (INIS)

    Neutron methods are emerging as an innovative and attractive investigative approach to characterising Cultural Heritage artefacts without the need for sampling or invasive procedures. Among Cultural Heritage collections conserved in national and private museums worldwide, metal artefacts of archaeological and historical interest, when properly studied, can reveal secrets of past human history. We are only allowed to treat them using the most delicate care and must avoid, as far as possible, accelerating any natural ageing process. Moreover, as analytical science evolves, we should not investigate these objects using invasive tools that might prevent further analytical techniques being applied to the same objects by future generations of scientists. In particular white beam and energy selective neutron radiography, tomography, and laminography can be successfully used to characterise the structure, morphology and composition of metal artworks by providing detailed three-dimensional information through the reconstruction of macroscopic cross sections of the object under investigation. From this wealth of data it is possible to obtain information on the conservation status of the artefact and reveal its manufacturing procedures, which in many cases may still be a mystery. In fact, the study of forging techniques, and their evolution over time, represents one of the most interesting topics in the investigation of metallic artefacts, which are considerably different within various cultures. In the present work, a comprehensive study of the metallurgy of metal artefacts of historical and archaeological interest in museums was carried out with the aim of investigating the composition, assembly methods, and structural variations in such artefacts from different cultures and different periods of history. The study has been developed in cooperation with several Museum Institutions and Neutron Facilities.

  17. Non-destructive techniques for biomonitoring of spatial, temporal, and demographic patterns of mercury bioaccumulation and maternal transfer in turtles

    International Nuclear Information System (INIS)

    Mercury (Hg) is a globally ubiquitous pollutant that has received much attention due to its toxicity to humans and wildlife. The development of non-destructive sampling techniques is a critical step for sustainable monitoring of Hg accumulation. We evaluated the efficacy of non-destructive sampling techniques and assessed spatial, temporal, and demographic factors that influence Hg bioaccumulation in turtles. We collected muscle, blood, nail, and eggs from snapping turtles (Chelydra serpentina) inhabiting an Hg contaminated river. As predicted, all Hg tissue concentrations strongly and positively correlated with each other. Additionally, we validated our mathematical models against two additional Hg contaminated locations and found that tissue relationships developed from the validation sites did not significantly differ from those generated from the original sampling site. The models provided herein will be useful for a wide array of systems where biomonitoring of Hg in turtles needs to be accomplished in a conservation-minded fashion. -- Highlights: ► Non-lethal sampling is critical for sustainable monitoring of mercury in wildlife. ► We evaluated the efficacy of non-lethal sampling techniques in turtles. ► We created mathematical models between egg, muscle, blood, and nail tissues. ► Mathematical tissue models were applicable to other mercury contaminated areas. ► Non-lethal techniques will be useful for monitoring contamination in other systems. -- We developed and validated mathematical models that will be useful for biomonitoring Hg accumulation in turtles in a conservation-minded fashion

  18. Biomonitoring of air pollution in Jamaica through trace-element analysis of epiphytic plants using nuclear and related analytical techniques

    International Nuclear Information System (INIS)

    Air quality has been monitored at selected areas in Jamaica using high volume samplers. The results obtained, showed elevated levels of aluminium in bauxitic areas and very high lead concentrations in urban areas, from 5 to 35 times greater than in rural areas. The lower throughput of the conventional air particulate samplers however, restricts the air quality and health assessment on a nation-wide scale. Biomonitoring offers a cost-effective alternative to air-quality assessment if appropriate indicator species are chosen. The epiphytic lower plants such as lichens and mosses have been used as indicators of regional air quality in several European countries and USA. However, there is not enough studies on lichens and mosses in tropical countries, probably due to the lower occurrence of these species, which cover only 8% of the world's land surface. In Jamaica the epiphytic higher plants, represented by the genus Tillandsia are widely distributed, which make them along with the lichens and mosses potential site-specific bioindicators of air quality. The IAEA Co-ordinated Research Project entitled 'Biomonitoring of Air Pollution in Jamaica Through Trace-Element Analysis of Epiphytic Plants Using Nuclear And Related Analytical Techniques' will address these needs of the country. The primary purpose of the present study was to develop specific bioindicators of atmospheric air pollution in Jamaica, which will provide baseline information for health hazards assessment

  19. Magnetic field visualization technique using neutrons

    International Nuclear Information System (INIS)

    Neutron radiography is utilized in the internal inspection of various materials due to the high sensitivity against light elements and excellent material transmission capability of neutrons. On the other hand, neutrons can interact directly with magnetic field because they have magnetic moment. As a result, neutron beams cause changes in spin state and orbit while passing through the magnetic field. If these changes can be detected for each position, the information about the magnetic field can be expressed as an image. This paper explains the characteristics of the magnetic field imaging using neutrons, in comparison with those of other techniques. Regarding the experimental examples of the visualization techniques using pulsed neutrons that have been performed in Japan, it introduces several examples in the stage of development at the Materials and Life Science Facility of J-PARC. In addition, it looks forward to the application and future of magnetic field imaging. (A.O.)

  20. Neutron flux measurement utilizing Campbell technique

    International Nuclear Information System (INIS)

    Application of the Campbell technique for the neutron flux measurement is described in the contribution. This technique utilizes the AC component (noise) of a neutron chamber signal rather than a usually used DC component. The Campbell theorem, originally discovered to describe noise behaviour of valves, explains that the root mean square of the AC component of the chamber signal is proportional to the neutron flux (reactor power). The quadratic dependence of the reactor power on the root mean square value usually permits to accomplish the whole current power range of the neutron flux measurement by only one channel. Further advantage of the Campbell technique is that large pulses of the response to neutrons are favoured over small pulses of the response to gamma rays in the ratio of their mean square charge transfer and thus, the Campbell technique provides an excellent gamma rays discrimination in the current operational range of a neutron chamber. The neutron flux measurement channel using state of the art components was designed and put into operation. Its linearity, accuracy, dynamic range, time response and gamma discrimination were tested on the VR-1 nuclear reactor in Prague, and behaviour under high neutron flux (accident conditions) was tested on the TRIGA nuclear reactor in Vienna. (author)

  1. Study of antarctic lichens as environmental biomonitors in the Admiralty Bay: preliminary study of trace elements contents by neutron activation analysis

    International Nuclear Information System (INIS)

    Al, As, Cu, Fe, Mn and Ti contents were analyzed for the epilithic antarctic lichen usnea antarctica, used as a biomonitors for air quality. The samples were taken in the surrounding area of the Peruvian scientific station 'Machu Picchu' on King George Island, in the Southern Shetland Archipelago (Antarctica). These elements have been assayed by neutron activation analysis (NAA). The preliminary obtained results support the hypothesis that an atmospheric circulation of chemicals exists on the assessed area and the activities developed at the different scientific stations located on this island would be a potential source of chemical pollutants for the evaluated area

  2. Neutron capture cross section measurement techniques

    International Nuclear Information System (INIS)

    A review of currently-used techniques to measure neutron capture cross sections is presented. Measurements involving use of total absorption and Moxon-Rae detectors are based on low-resolution detection of the prompt γ-ray cascades following neutron captures. In certain energy ranges activation methods are convenient and useful. High resolution γ-ray measurements with germanium detectors can give information on the parameters of resonance capture states. The use of these techniques is described. (U.S.)

  3. Environmental studies by means of the use of biomonitors (Tillandsia sp.) and nuclear techniques

    International Nuclear Information System (INIS)

    The lack of healthful atmosphere is one of the main causes of health deterioration. The present study uses biomonitors, with the objective of knowing the levels of pollutant accumulation in nucleus zones, by means of Tillandsia's spp. sampling (a Bromeliaceae, epiphyte that captures the atmosphere's nutrients and concomitantly accumulates heavy metals) during the spring station. They correspond to intersections between avenues with high vehicular flow and particular characteristics as for mobile emission's sources, in Asuncion City; subdivided in such form that, each plant has the same probability to be selected, being 5 species of Tillandsia: T. recurvata L. (94%); T. meridionalis Baker (59%); T loliaceae Mart. (29%); T. duratii Visiani (12%), and T. tricholepis Baker (6%). These species were evaluated for element levels by means of X ray fluorescence energy dispersive, with conventional geometry. (author)

  4. Determination of hydrogen content by neutron techniques

    International Nuclear Information System (INIS)

    The commonly available techniques for the determination of hydrogen dissolved in solids are usually destructive from the point of view of the sample. A new, nondestructive method for this kind of measurements has been developed at our laboratory, with the requirement of improved sensitivity for massive samples. This scattering method is based on the use of epithermal neutrons, and has been implemented through the design and construction of a spectrometer dedicated to that task. In addition, the traditional transmission method has been employed to determine hydrogen content in metals, using the full sub thermal and thermal neutron energy ranges. A pulsed neutron source based on an electron LINAC is employed, together with time-of-flight techniques. In this work we will present some results illustrative of the sensitivity achieved by these neutron techniques in different systems and for a wide range of hydrogen concentrations. (author)

  5. BIOMONITORING USING AQUATIC VEGETATION

    Science.gov (United States)

    This chapter provides an overview of the state-of-the-science as related to the phytoassessment techniques used in environmental biomonitoring and the hazard assessment process for chemicals. The emphasis is on freshwater angiosperms and bryophytes. Algal species, which are prese...

  6. Quality control of INAA-k0 and ICP-MS as bio-monitoring analysis techniques - Application to Moroccan atmospheric pollution study

    International Nuclear Information System (INIS)

    Full text: Many studies have been conducted to study atmospheric pollution using different techniques to determine the quality and quantity of pollutant elements. Those techniques differ in their capability of analysing as large spectrum of elements as possible, their sensibility to the presence of trace elements and their accuracy. In this study the interest turns on the INAA-k0 and ICP-MS techniques due to their adequate characteristics to analyse accurately a wide number of elements interesting the bio monitoring. To check the measurement reliability and accuracy of those two techniques, we have analysed samples of reference materials and compared analysis results of divers elements in lichens, mosses and tree barks. The results given by reference materials analysis and bio-monitor comparisons let us conclude that INAA-k0 and ICP-MS are very suitable for the bio-monitoring task, complementary and they can be substituted for analysis of the majority of elements. (author)

  7. Neutron Scattering in Biology Techniques and Applications

    CERN Document Server

    Fitter, Jörg; Katsaras, John

    2006-01-01

    The advent of new neutron facilities and the improvement of existing sources and instruments world wide supply the biological community with many new opportunities in the areas of structural biology and biological physics. The present volume offers a clear description of the various neutron-scattering techniques currently being used to answer biologically relevant questions. Their utility is illustrated through examples by some of the leading researchers in the field of neutron scattering. This volume will be a reference for researchers and a step-by-step guide for young scientists entering the field and the advanced graduate student.

  8. Techniques in high pressure neutron scattering

    CERN Document Server

    Klotz, Stefan

    2013-01-01

    Drawing on the author's practical work from the last 20 years, Techniques in High Pressure Neutron Scattering is one of the first books to gather recent methods that allow neutron scattering well beyond 10 GPa. The author shows how neutron scattering has to be adapted to the pressure range and type of measurement.Suitable for both newcomers and experienced high pressure scientists and engineers, the book describes various solutions spanning two to three orders of magnitude in pressure that have emerged in the past three decades. Many engineering concepts are illustrated through examples of rea

  9. Biomonitoring of air pollution with heavy metals in the Republic of Macedonia by neutron activation analysis

    International Nuclear Information System (INIS)

    Atmospheric deposition of trace metals was studied over the entire territory of the Republic of Macedonia in 2002 and 2005. Samples of the terrestrial mosses Hypnum cupressiforme, Camptothecium lutescens, and Homalothecium sericeum were collected at 73 sites in 2002 and at 72 sites in 2005. Instrumental neutron activation analysis allowed determination of 41 elements in 2002 and 38 elements in 2005. Principal component factor analysis was used to identify the most polluted areas and characterize different pollution sources. The most important sources of trace metal deposition are ferrous and non-ferrous smelters, oil refineries, fertilizer production plants, and central heating station. four areas appear to be particularly exposed to metal pollution: Veles, Skopje, Tetovo, and Kavadarci - Negotino. Comparison of the results from the first and the second moss survey, showed that there is no significant difference in median values of elemental concentrations determined, besides Ni. The more then twofold increase of its median value is explained by renewed activity of ferronickel smelter in Kavadartsi. (Author)

  10. Vanadium determination in Perna perna mussels (Linnaeus, 1758: Mollusca, Bivalvia) by instrumental neutron activation analysis using the passive biomonitoring in the Santos coast, Brazil

    International Nuclear Information System (INIS)

    Vanadium determination present in seawater is of great importance to evaluate marine contamination from industrial sources as well as to identify health hazards since mussels and other marine organisms are used as food. Besides, this evaluation in the Santos coast, SP, Brazil, is important, since this area is impacted by industrial and urban activities and discharges from ships and boats. In a previous study, V results obtained for transplanted mussel (active biomonitoring) were presented. This study aimed the V determination by passive biomonitoring by analyzing Perna perna mussels collected in natural environment, from three sites in Sao Paulo State coast: Cocanha Beach (reference site), Ponta de Itaipu and Palmas Island. Ninety individuals of mussels were collected in each site between September/08 and July/09 during the four seasons of the year. After shell removal and sample preparation, V was determined by instrumental neutron activation analysis. For analytical quality control, the NIST Standard Reference Material SRM 1566b Oyster Tissue was analyzed and the results presented good accuracy. The V concentrations in mussels on dry mass basis varied from 0.77 ± 0.02 to 3.56 ± 0.88 mg kg-1. Statistical tests were applied to the results showing differences on V concentrations among the sampling sites and season of sample collection. (author)

  11. Applications of neutron activation analysis technique

    International Nuclear Information System (INIS)

    The technique was developed as far back as 1936 by G. Hevesy and H. Levy for the analysis of Dy using an isotopic source. Approximately 40 elements can be analyzed by instrumental neutron activation analysis (INNA) technique with neutrons from a nuclear reactor. By applying radiochemical separation, the number of elements that can be analysed may be increased to almost 70. Compared with other analytical methods used in environmental and industrial research, NAA has some unique features. These are multi-element capability, rapidity, reproducibility of results, complementarity to other methods, freedom from analytical blank and independency of chemical state of elements. There are several types of neutron sources namely: nuclear reactors, accelerator-based and radioisotope-based sources, but nuclear reactors with high fluxes of neutrons from the fission of 235U give the most intense irradiation, and hence the highest available sensitivities for NAA. In this paper, the applications of NAA of socio-economic importance are discussed. The benefits of using NAA and related nuclear techniques for on-line applications in industrial process control are highlighted. A brief description of the NAA set-ups at CERT is enumerated. Finally, NAA is compared with other leading analytical techniques

  12. Development of neutron visual sensing techniques

    International Nuclear Information System (INIS)

    Neutron visual sensing techniques are powerful and attractive advanced techniques for many kinds of scientific and industrial fields. In this article, the followings are described; (1) attractive points, (2) development of neutron visual sensing techniques at JAEA by now, (3) some applications, (4) prospects for future and (5) problems for the spread. The high-speed 2D method, high-speed scanning 3D/4D CT method, and multi-beam 4D CT method which have been developed by JAEA are reported. Visualization of oil flow in a mortaring car engine by the high-speed 2D method and 4D view of the falling sand flow in sand glasses by the high-speed scanning 4D CT method, which are carried out using JRR-3, are shown as application samples. Now, we run toward the development of the advanced pulse neutron visual sensing techniques for the multi-purpose applications using J-PARC as the pulse neutron source. (author)

  13. Neutron radiographic techniques, facilities and applications

    International Nuclear Information System (INIS)

    This is a collection of three papers, written for presentation on two international conferences. The first paper: ''Neutron radiography. Techniques and facilities'', written by J.P. Barton of N-Ray Engineering Co. La Jolla, CA., USA and J.C. Domanus was presented at the International Symposium on the Use and Development of Low and Medium Flux Research Reactors at the Massachusets Institute of Technology, Cambridge, Mass., USA, 16-19 October 1983. The second paper: ''Neutron radiography with the DR-1 reactor at Risoe National Laboratory'', written by J.C. Domanus, was presented at the same Symposium. The third paper: ''Defects in nuclear fuel revealed by neutron radiography'', written by J.C. Domanus is accepted for presentation on 18 October 1984 to the 3rd European Conference on Nondestructive Testing, Florence, Italy, 15-18 October 1984. While the first paper describes the principles of neutron radiographic techniques and facilities, the second one describes an example of such facility and the third gives an example of application of neutron radiography in the field of nuclear fuel. (author)

  14. Bio-monitoring studies using nuclear and related techniques for the study of air pollution in and around the city of Hyderabad, India

    International Nuclear Information System (INIS)

    Passive bio-monitoring using different plant species affords a cost effective approach to studies on environmental trace element pollution. Lower plants like mosses and lichens have already been demonstrated to be effective bio monitors. As part of our participation in the IAEA's Co-ordinated Research Program on 'Validation and application of plants as bio-monitors of trace element atmospheric pollution analyzed by nuclear and related techniques', we have carried out studies on the use of a moss (Funaria hygrometrica) and a shrub (Lanatana Camera). About 35 sampling locations covering industrial zones, locations with heavy traffic, commercial and residential areas were identified. The samples have been analyzed using ICP-MS and PIGE to provide elemental concentrations on a number of the moss show physical trapping of fine particulate matter. The data are examined with a view to assess the use of these plants as bio-monitors of toxic trace elements. The moss, available only during the monsoon, shows, on a dry weight basis, much higher levels of concentrations for many elements, than the shrub (leaves). The concentration profiles in relation to the sampling locations suggest that metallic pollution can be easily discerned. The elemental data are examined using principle component analysis. While the qualitative identification of the metallic pollutants is easier with reference to the sampling locations, it would also require complimentary information using other techniques to provide a quantitative estimate of total environmental trace element burden. (author)

  15. Neutron visual sensing techniques making good use of computer science

    International Nuclear Information System (INIS)

    Neutron visual sensing technique is one of the nondestructive visualization and image-sensing techniques. In this article, some advanced neutron visual sensing techniques are introduced. The most up-to-date high-speed neutron radiography, neutron 3D CT, high-speed scanning neutron 3D/4D CT and multi-beam neutron 4D CT techniques are included with some fundamental application results. Oil flow in a car engine was visualized by high-speed neutron radiography technique to make clear the unknown phenomena. 4D visualization of pained sand in the sand glass was reported as the demonstration of the high-speed scanning neutron 4D CT technique. The purposes of the development of these techniques are to make clear the unknown phenomena and to measure the void fraction, velocity etc. with high-speed or 3D/4D for many industrial applications. (author)

  16. Study of air pollution in Chile using biomonitors

    International Nuclear Information System (INIS)

    A project has been undertaken within the framework of a Co-ordinated Research Programme (CRP) supported by the International Atomic Energy Agency (IAEA) to carry out a long term study on atmospheric air pollution in Chile using biomonitors. The present project aims at the selection of appropriate plants and other indicators for monitoring of air pollution in several cities and rural areas in Chile. Nuclear analytical techniques, in particular neutron activation analysis (NAA) will be used complemented by AAS for the analysis of selected elements and to determine the sources of pollutants and the applicability of biomonitors to study air pollution in large areas, using indicators either naturally grown or artificially introduced to the region under examination. (author)

  17. Biomonitoring and assessment of monomethylmercury exposure in aqueous systems using the DGT technique

    Energy Technology Data Exchange (ETDEWEB)

    Clarisse, O., E-mail: olivier.clarisse@umoncton.ca [Trent University, Chemistry Department, 1600 West Bank Drive, Peterborough, ON K9J 7B8 (Canada); Universite de Moncton, Departement de Chimie et de Biochimie, Moncton, New Brunswick E1A 3E9 (Canada); Lotufo, G.R. [Environmental Laboratory, U.S. Army Engineer Research and Development Center, Vicksburg, MS 39180-6199 (United States); Hintelmann, H. [Trent University, Chemistry Department, 1600 West Bank Drive, Peterborough, ON K9J 7B8 (Canada); Best, E.P.H. [Environmental Laboratory, U.S. Army Engineer Research and Development Center, Vicksburg, MS 39180-6199 (United States); U.S. Environmental Protection Agency, National Risk Management Research Laboratory, 26 West Martin Luther King Boulevard, Cincinnati, OH 45268 (United States)

    2012-02-01

    A series of laboratory experiments was conducted under realistic environmental conditions to test the ability of the Diffusive Gradient in Thin film (DGT) technique to mimic monomethylmercury (MMHg) bioaccumulation by a clam (Macoma balthica, Baltic clam). Using isotope enriched MMHg as tracers, bioavailability was determined by comparing the rate of MMHg uptake by novel DGT devices and sentinel organism over time. Experiments were conducted under varying conditions of salinity and MMHg speciation. Depending on MMHg level and speciation in the dissolved phase, MMHg uptake rates by the sentinel organism varied greatly from 0.4 to 2.4 L g{sup -1} d{sup -1}. Reproducibilities of MMHg uptakes by DGT and clams were estimated at 7 and 38%, respectively. A significant linear relationship (log basis) between MMHg accumulation by DGT and clams was observed (r{sup 2} = 0.89). The study demonstrates that DGT results reasonably predict MMHg uptake by clams from the aqueous phase and provide the basis for application of the DGT device as a surrogate for sentinel organism for monitoring bioavailable MMHg. - Highlights: Black-Right-Pointing-Pointer We investigate the potential of DGT devices to act as surrogates for sentinel organism. Black-Right-Pointing-Pointer We compare monomethylmercury accumulation in DGT devices and in clams from the dissolved phase. Black-Right-Pointing-Pointer We examine the effects of salinity and MMHg speciation on MMHg accumulation by DGT and clams. Black-Right-Pointing-Pointer For all laboratory experiments, a strong overall correlation between MMHg accumulations in clams and DGTs is observed.

  18. Development of imaging techniques for fast neutron radiography in Japan

    CERN Document Server

    Fujine, S; Yoshii, K; Kamata, M; Tamaki, M; Ohkubo, K; Ikeda, Y; Kobayashi, H

    1999-01-01

    Neutron radiography with fast neutron beams (FNR) has been studied at the fast neutron source reactor 'YAYOI' of the University of Tokyo since 1986. Imaging techniques for FNR have been developed for CR-39 track-etch detector, electronic imaging system (television method), direct film method, imaging plate and also fast and thermal neutron concurrent imaging method. The review of FNR imaging techniques and some applications are reported in this paper.

  19. Development of imaging techniques for fast neutron radiography in Japan

    International Nuclear Information System (INIS)

    Neutron radiography with fast neutron beams (FNR) has been studied at the fast neutron source reactor 'YAYOI' of the University of Tokyo since 1986. Imaging techniques for FNR have been developed for CR-39 track-etch detector, electronic imaging system (television method), direct film method, imaging plate and also fast and thermal neutron concurrent imaging method. The review of FNR imaging techniques and some applications are reported in this paper

  20. Neutron contrast techniques applied to oxide glasses

    International Nuclear Information System (INIS)

    Neutron scattering with isotopic substitution, particularly first and second difference methods, are proving to be excellent techniques for studies of the structure of oxide glasses. Several examples are given in which the measurements provide information that is difficult or impossible to obtain otherwise, for example, accurate, detailed distributions of first- to third-neighbours of Ca, Cu or Ni in silicate and phosphate glasses. In favourable cases, it is also possible to measure, directly, Ca-Ca and Ni-Ni first- and second-neighbour distributions. The relevance of complementary techniques, XAFS, differential anomalous x-ray scattering, x-ray scattering from glasses containing elements of high atomic numbers, is also discussed. (author). 6 figs., 11 refs

  1. Neutron calibration techniques for comparison of tokamak results

    International Nuclear Information System (INIS)

    A workshop on 1--3 August 1989 reviewed the techniques, uncertainties, and experiences of neutron calibration on PLT, TFTR, JET, Tore Supra, JT-60, JIPPT-IIU, Alcator C-Mod, ATF, FT, ASDEX, Textor, and DIII-D. In the summary session, the workshop participants discussed possible consensus neutron calibration techniques appropriate to D-D plasmas in tokamaks. The application of such techniques would facilitate a more accurate comparison of neutron yields from different devices, and also allow new calibration techniques to relate their precision to a reference value. General agreement was reached on the suitability of two techniques: (1) a 252Cf source calibration of epithermal neutron detectors, and (2) threshold neutron activation of Ni foils placed vertically above or below the plasma. This paper will present details on detector positioning, neutron transport calculations, and interlab normalization needed to accomplish the standardized calibration using a Cf neutron source

  2. Macroscopic cross section measurements in materials by neutron radiography technique

    International Nuclear Information System (INIS)

    Macroscopic cross-section of materials play an important role in the study of material properties. Number of materials are used for shielding against penetrating radiation like X-rays, gamma rays and neutrons and exhibit different attenuation cross-sections. Neutron radiography technique is a multi discipline non-destructive technique with a large number of applications. The technique was applied to study and analyze the behavior of different shielding materials against thermal neutrons. Samples as step wedges of graphite, copper, brass and acrylic etc. were fabricated. The test samples were exposed to a beam of thermal neutrons at neutron radiography facility and the transmittance of neutrons through different materials was measured. Gamma-ray contribution and scattered radiation were subtracted from the observed neutron intensities to calculate the neutron macroscopic cross-section. Calculated values of the macroscopic cross-section were compared with the values given in the literature. (author)

  3. Lectures on neutron scattering techniques: 1

    International Nuclear Information System (INIS)

    The lecture on the production of neutrons was presented at a Summer School on neutron scattering, Rome, 1986. A description is given of the production of neutrons by natural radioactive sources, fission, and particle accelerator sources. Modern neutron sources with high intensities are discussed including the ISIS pulsed neutron source at the Rutherford Appleton Laboratory and the High Flux Reactor at the Institut Laue Langevin. (U.K.)

  4. Combination of multielement technique (INAA and ICP-MS) for a French air pollution bio-monitoring survey using mosses

    International Nuclear Information System (INIS)

    This work presents the use of two trace analysis techniques through the data obtained for a significant part of the 557 mosses sampled in France. Sampling were made within the framework of European survey carried out in 1995-1996 and proposed by the Nordic Council. The analyses were produced with a combination of two multielement analysis techniques: INAA (Instrumental Neutron Activation Analysis) and ICP-MS (Inductively Coupled Plasma Mass Spectrometry). Theses two techniques were suitable for trace analyses in mosses. They were clearly complementary and provided for 36 elements including the heavy metals of key interest in air pollution studies. The choice of the technique for a given element depended on the feasibility (e g. Pb is not attainable by INAA), the detection limit, the analytical variability, the preparation procedures and the concentration ranges (5-100 μg/g for Pb, 0.5-5 μg/g for As). INAA measured the total content in the sample, while ICP-MS demanded a mineralization procedure resulting in losses/contamination hazards. Thus, INAA results were preferred, although this technique was time consuming. However the ICP-MS results for Cd, Cu, Ni and Pb were retained, for different reasons: detection limits (Cd, Cu), no convenient INAA conditions (Ni), and feasibility (Pb). (authors)

  5. A new neutron noise technique for fast reactors

    International Nuclear Information System (INIS)

    This paper gives a new neutron noise technique for fast reactors, which is known as thermalization measurement technique of the neutron noise. The theoretical formulas of the technique were developed, and a digital delayed coincidence time analyzer consisted of TTL integrated circuits was constructed for the study of this technique. The technique has been tested and applied practically at Df-VI fast zero power reactor. It was shown that the provided technique in this work has a number of significant advantages in comparison with the conventional neutron noise method

  6. A Heavy Metal Atmospheric Deposition Study Around the Lead and Copper-Zinc Smelters in Baia Mare, Romania, Employing the Moss Biomonitoring Technique, ENAA and FAAS

    CERN Document Server

    Culicov, O A; Steinnes, E; Okina, O S; Santa, Z; Todoran, R

    2001-01-01

    The mosses Pleurozium schreberi, Pseudoscleropodium purum and Rhytidiadelphus squarrosus were used as biomonitors to study the atmospheric deposition of metals around the lead and copper-zinc smelters in Baia Mare. Samples representing the last three years' growth of moss or its green part, collected on the ground at 28 sites located 2-20 km from the source area, were analyzed by instrumental neutron activation analysis using epithermal neutrons (ENAA) and by flame atomic absorption spectrometry (FAAS). A total of 30 elements were determined, including most of the heavy metals known to be released into the air from this kind of industry. Obtained concentrations for As and Cu are comparable with those observed in Karabash, South Ural Mountains, one of the most polluted regions in Europe. Besides, these two elements correlate very well with each other. The mean values for Zn (136 ppm) and Pb (41 ppm) are substantially higher than those normally found in the literature. The highest value for Pb (175 ppm) was obs...

  7. A new technique for neutron monitoring in stray radiation fields

    International Nuclear Information System (INIS)

    At reactors, accelerators and therapy facilities including linear accelerators there is the need to monitor low level stray radiation fields, Neutron monitoring today is based mainly on the application of rem counters. A new approach to neutron monitoring is described which allows one to measure the dose equivalent of neutrons and gamma rays and to interpret neutron spectra in stray radiation fields in terms of Esub(e)sub(f)sub(f) and the dose fractnon of thermat neutrons. Compared to the muttisphere technique only a single moderator sphere of 30 cm diam and various pairs of TLD600/TLD7O0 detectors as passive neutron/gamma detectors are applied to measure moderated neutrons in the center of the sphere, backscattered albedo neutrons on the surface of the sphere and thermal as well as epithermal neutrons from the stray radiation field directly. The passive dosimeter system is sensitive to neutrons in the dose range 10 mrem - 500 rem and permits long-term exposures of several months. Field exposures performed at different facilities are described showing representative results for a neutron stray radiation field with Esub(e)sub(f)sub(f) between 2 MeV down to 100 keV and dose contributions from thermal neutrons between 1% and 30% depending on the kind of neutron stray source, the distance from the source, and the concrete shieldings in the room. (H.K.)

  8. Novel techniques to search for neutron radioactivity

    CERN Document Server

    Thoennessen, M; Kohley, Z; Baumann, T; Jones, M; Smith, J K; Snyder, J; Spyrou, A

    2013-01-01

    Two new methods to observe neutron radioactivity are presented. Both methods rely on the production and decay of the parent nucleus in flight. The relative velocity measured between the neutron and the fragment is sensitive to half-lives between ~1 and ~100 ps for the Decay in Target (DiT) method. The transverse position measurement of the neutron in the Decay in a Magnetic Field (DiMF) method is sensitive to half-lives between 10 ps and 1 ns.

  9. Tillandsia usneoides L, a biomonitor in the determination of Ce, La and Sm by neutron activation analysis in an industrial corridor in Central Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Isaac-Olive, K. [Facultad de Medicina. Universidad Autonoma del Estado de Mexico, Paseo Tollocan s/n, esq. Jesus Carranza, Toluca, 50120 Estado de Mexico (Mexico); Solis, C., E-mail: corina@fisica.unam.mx [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, 04510 Mexico DF (Mexico); Martinez-Carrillo, M.A; Andrade, E. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, 04510 Mexico DF (Mexico); Lopez, C.; Longoria, L.C. [Instituto Nacional de Investigaciones Nucleares (ININ), Salazar, 50045 Estado de Mexico (Mexico); Lucho-Constantino, C.A. [Universidad Politecnica de Pachuca, Carretera Pachuca-Cd. Sahagun, Km. 20., Hidalgo, Mexico (Mexico); Beltran-Hernandez, R.I. [Centro de Investigaciones Quimicas, Universidad Autonoma del Estado de Hidalgo. Carretera Pachuca-Tulancingo km. 4.5, 42184, Pachuca, Hidalgo (Mexico)

    2012-04-15

    The atmosphere of the Tula Industrial Corridor in Central Mexico is contaminated due to several industries including oil refining while station monitoring in this area are limited. Lanthanides are considered fingerprint of oil refinery activities, and La, Ce and Sm have been previously detected in this area using filters. The suitability of T. usneoides as a biomonitor assessing the La, Ce and Sm concentrations in Particulate Matter is evaluated by NAA. Results of both biomonitor and filters are highly correlated.

  10. Tillandsia usneoides L, a biomonitor in the determination of Ce, La and Sm by neutron activation analysis in an industrial corridor in Central Mexico

    International Nuclear Information System (INIS)

    The atmosphere of the Tula Industrial Corridor in Central Mexico is contaminated due to several industries including oil refining while station monitoring in this area are limited. Lanthanides are considered fingerprint of oil refinery activities, and La, Ce and Sm have been previously detected in this area using filters. The suitability of T. usneoides as a biomonitor assessing the La, Ce and Sm concentrations in Particulate Matter is evaluated by NAA. Results of both biomonitor and filters are highly correlated.

  11. Personnel neutron monitoring based on albedo technique

    International Nuclear Information System (INIS)

    This work deals with the study, design and test of a personal neutron monitor based on the detection of albedo neutrons from the body and its further relation to the incident flux. By this method, neutrons of energies below about 100 KeV can be efficiently detected, providing good information in the region where the biological effectiveness of neutron radiation starts to rise. The system consists of a pair of Thermoluminescent Detectors (6 LiF - 7 LiF) ∼ inside a polyethylene moderating body, in order to increase the sensitivity. The surface of the dosimeter facing away from the body is covered by a layer of a borated resin to assure appropriate shielding of incident low energy neutrons. The response of the dosimeter to monoenergetic neutrons from a 3 MeV Van de Graaff, to Am Be neutrons and to neutrons from a thermal column was investigated. The directional sensitivity, the effect of beam divergence was well as the effect of changes in dosimeter-to-body distances were also studied. (author)

  12. Neutron magnetic tomography - A novel technique

    International Nuclear Information System (INIS)

    A tomographic neutron depolarization algorithm is described to visualize magnetic structures within bulk samples which takes fully into account the tensorial character of neutron spin rotations. Successful reconstructions of simulated domain configurations demonstrate the mathematical feasibility of this new concept. (orig.)

  13. Studies using nuclear and complementary non-nuclear analytical techniques for bio-monitoring of air pollution

    International Nuclear Information System (INIS)

    A set of lower and higher plants have been analysed for their trace element contents. The plants are, a moss (Funaria sp.), a bryophyte (Cyathodium sp.), a weed (Parthenium hysterophorus L.) and a common bushy shrub (Lantana Camera L.). The trace element concentrations have been determined using INAA, PIGE and ICP-OES. The data are examined with a view to assess the use of these plants as bio-indicators of toxic trace metal pollutants in ambient air. The moss and the bryophyte samples show much higher accumulation levels for many elements, but are seasonal. The other two plants, due to their perennial nature, can be used for bio-monitoring purposes, almost throughout the year. (author)

  14. Evaluation of neutron techniques for illicit substance detection

    International Nuclear Information System (INIS)

    The authors are studying inspection systems based on the use of fast neutrons for detecting illicit substances such as explosives and drugs in luggage and cargo containers. Fast neutron techniques can determine the quantities of light elements such as carbon, nitrogen, and oxygen in a volume element. Illicit substances containing these elements are characterized by distinctive elemental densities or density ratios. They discuss modeling and tomographic reconstruction studies for fast-neutron transmission spectroscopy

  15. Evaluation of neutron techniques for illicit substance detection

    International Nuclear Information System (INIS)

    We are studying inspection systems based on the use of fast neutrons for detecting illicit substances such as explosives and drugs in luggage and cargo containers. Fast-neutron techniques can determine the quantities of light elements such as carbon, nitrogen, and oxygen in a volume element. Illicit substances containing these elements are characterized by distinctive elemental densities or density ratios. We discuss modeling and tomographic reconstruction studies for fast-neutron transmission spectroscopy. (orig.)

  16. Measurement of neutron electric charge by the spin interferometry technique

    International Nuclear Information System (INIS)

    Full text: New experiment for checking neutron electro neutrality is proposed. The main idea of this experiment is to use the spin interferometry technique. Such technique is used in SESANS (Spin Echo Small Angle Neutron Scattering) installations for condense matter investigations. There is a spatial splitting of neutron on two eigenstates with different projection of spin on magnetic field. After passing through the working area these two eigenstates are reduced back. So, the phase of the interference pattern, i.e. azimuthal spin direction, is defined by phase difference of two neutron eigenstates, accumulated in working area. If such system is placed into uniform electric field E, then two neutron eigenstates, due to their spatial splitting, will be under different electric potentials. With presence of electric charge of neutron qn it will give the energy splitting ΔEe=qn E Δz and, respectively, will give additional phase shift Δφe=ΔEe τ/ℎ, where Δz - value of spatial splitting, τ - time of staying of the neutron in electric field. So, one can see that such system is sensitive to neutron electric charge. Preliminary estimations show the using of technique mentioned above can improve the recent restriction on neutron electric charge on order of magnitude as minimum and it can reach the value better than σ(qn)∼10-22e. (author)

  17. Experimental techniques for the consolidation of the neutron spectrum

    International Nuclear Information System (INIS)

    Unfolding techniques are widely known but their use is not widespread due to their complexity. Such procedure consists in the adjustment of calculated quantities to experimental results by the modification of the neutron spectrum, getting correction factors for the calculated quantities. In this work we describe the general procedure that must be executed for a neutron spectrum unfolding. (author)

  18. A heavy metal atmospheric deposition study around the lead and copper-zinc smelters in Baia Mare, Romania, employing the moss biomonitoring technique, ENAA and FAAS

    International Nuclear Information System (INIS)

    The mosses Pleurozium schreberi, Pseudoscleropodium purum and Rhytidiadelphus squarrosus were used as biomonitors to study the atmospheric deposition of metals around the lead and copper-zinc smelters in Baia Mare. Samples representing the last three years' growth of moss or its green part, collected on the ground at 28 sites located 2-20 km from the source area, were analyzed by instrumental neutron activation analysis using epithermal neutrons (ENAA) and by flame atomic absorption spectrometry (FAAS). A total of 30 elements were determined, including most of the heavy metals known to be released into the air from this kind of industry. Obtained concentrations for As and Cu are comparable with those observed in Karabash, South Ural Mountains, one of the most polluted regions in Europe. Besides, these two elements correlate very well with each other. The mean values for Zn (136 ppm) and Pb (41 ppm) are substantially higher than those normally found in the literature. The highest value for Pb (175 ppm) was observed in a sample collected in the vicinity of the lead plant. The mean value for Sb (0.56 ppm) is much higher than the background level in Norway but 5 times lower than the mean Sb concentration in parts of the South Ural Mountains. A high correlation between Pb and Sb was observed. Moreover this study evidences the endemic character of the examined area due to iodine depletion. Its mean value in the moss is 2.5 times lower than the background level in Norway and systematically lower than the mean European values

  19. Calibration technique for the neutron surface moisture measurement system

    International Nuclear Information System (INIS)

    A technique for calibrating the response of a surface neutron moisture measurement probe to material moisture concentration has been devised. Tests to ensure that the probe will function in the expected in-tank operating environment are also outlined

  20. Application of neutron backscatter techniques to level measurement problems

    International Nuclear Information System (INIS)

    We have designed and built portable level detectors and fixed level monitors based on neutron scattering and detection principles. The main components of these devices, which we call neutron backscatter gauges, are a neutron emitting radioisotope, a neutron detector, and a ratemeter. The gauge is a good detector for hydrogen but is much less sensitive to most other materials. This allows level measurements of hydrogen bearing materials, such as hydrocarbons, to be made through the walls of metal vessels. Measurements can be made conveniently through steel walls which are a few inches thick. We have used neutron backscatter gauges in a wide variety of level measurement applications encountered in the petrochemical industry. In a number of cases, the neutron techniques have proven to be superior to conventional level measurement methods, including gamma ray methods

  1. Transmission and Reflection of Neutrons Using Foil Activation Technique

    International Nuclear Information System (INIS)

    A new neutron irradiation facility has been designed, constructed .and located at the Experimental Nuclear Physics Department, NRC, AEA, cairo. The neutrons were obtained from CNIF2 (Second Cairo Neutron Irradiation Facility) that is based on one 241 Am-Be(α, n) isotopic neutron source with a present activity of about 175 GBq results in a neutron yield of about 1.04 x107 n/s. The geometrical arrangements of the facility consider the safety and protection rules aspects. MCNP5 code is used to estimate radiation doses and neutron fluxes. This new irradiation facility provides fast and epithermal neutrons that can be used in basic research and industrial applications. The aim of the present work is to study the characteristics of this new irradiation facility and to develop methods able to use fast and epithermal neutron in some different applications. Experimental measurements for the transmission and reflection of neutrons were carried out via a number of hydrogenous materials using the activation foil technique. A comparison of the experimental results with that calculated by using Monte Carlo simulation method is presented Using the neutron transmission technique in combination with foil activation method, our arrangement is used to measure the total neutron microscopic cross-sections for some compounds. The facility is calibrated and suitable to estimate the hydrogen content H (wt %) and the weight ratios C/H in hydrocarbon materials and was used to measure these ratios for some Egyptian crude oil samples. A brief overview of the neutron activation analysis methods for elemental concentrations in bulk samples in natural conditions is presented.

  2. Experimental technique of small angle neutron scattering

    International Nuclear Information System (INIS)

    The main parts of Small Angle Neutron Scattering (SANS) spectrometer, and their function and different parameters are introduced from experimental aspect. Detailed information is also introduced for SANS spectrometer 'Membrana-2'. Based on practical experiments, the fundamental requirements and working condition for SANS experiments, including sample preparation, detector calibration, standard sample selection and data preliminary process are described. (authors)

  3. Assessment of air quality in Mangabeiras' Park, Belo Horizonte, Brazil, using epiphytic lichens as biomonitor

    International Nuclear Information System (INIS)

    Biomonitoring has been used as an alternative method to study the air pollution in several countries. The lichen, or lichenized fungi, is one of the most efficient on air pollution biomonitoring among the biomonitors. However, in Brazil, systematic use of lichens as biomonitors of environmental pollution is quite rare. In order to make an assessment of the air quality of the Mangabeiras' Park, this study was conducted by measuring the concentration of elements accumulated in the lichen thallus. This park, located in Belo Horizonte (Minas Gerais, Brazil), is the greatest green area in the city, and an apparent region of non polluted air. During the development of the study, epiphytic lichens of several species were collected using a steel stainless knife, taking samples of similar sizes from 1.5 m from the soil. The lichens selection was based on morphological similarities, such as color and type of the thallus. The elemental concentration determination was carried out applying the neutron activation technique, k0-standardization method, using the TRIGA Mark I IPR-R1 research reactor located at CDTN/CNEN. The lichen samples presented expressive concentrations of Ba, Fe, K, Na and Zn. However, the presence of other characteristic soil elements from the region, such as As, Th and U, suggests the influence of the mining activity area, located in the surroundings. (author)

  4. Biomonitoring of air pollution through trace element analysis

    International Nuclear Information System (INIS)

    Studies are being carried out to determine the potential and reliability in the use of local lichen species for biomonitoring air pollution in Ghana. The location of most of the gold mines in forest areas of the country presents the gold mining industry as a suitable setting for such investigations. The nuclear-related techniques being used in the multielement analysis of lichen samples and air filter samples are instrumental neutron activation analysis (Miniature Neutron Source Reactor) and energy dispersive x-ray fluorescence analysis (tube-excitation). Validation of the quantitative methods of the INAA through analysis of standard certified reference materials of orchard leaves NBS SRM 1571 and BCR-CRM No. 279 gave very good results for most elements analyzed. Elemental analysis of identified lichen samples will be done bearing in mind microclimatic factors, specie type and nature of soil. (author)

  5. Biomonitoring of air pollution through trace element analysis

    International Nuclear Information System (INIS)

    Studies are being carried out to determine the potential and reliability in the use of local lichen species for biomonitoring air pollution in Ghana. The location of most of the gold mines in forest areas of the country presents the gold mining industry as a suitable setting for such investigations. The nuclear-related techniques being used in the multielement analysis of lichen samples and air filter samples are instrumental neutron activation analysis (Miniature Neutron Source Reactor) and energy dispersive x-ray fluorescence analysis (tube-excitation). Validation of the quantitative methods of the INAA through analysis of standard and certified reference materials of orchard leaves NBS SRM 1571 and BCR-CRM No. 279 gave very good results for most elements analyzed. Elemental analysis of identified lichen samples will be done beating in mind microclimatic factors, specie type and nature of soil. (author)

  6. Biomonitoring of air pollution through trace element analysis

    International Nuclear Information System (INIS)

    Research work is currently going on to determine the suitability in the use of local lichen species for biomonitoring air pollution in Ghana. The study areas being investigated are the gold-mining areas situated in the Moist Evergreen and Semi-Deciduous forests in Ghana. The nuclear analytical techniques being used in this work are instrumental neutron activation analysis and tube-excited x-ray fluorescence spectrometry. The present report covers results of quality control exercise carried out to validate the quantitative methods being used. This includes our participation in an intercomparison exercise carried out among participants of the IAEA coordinated research project. The samples analyzed were two lichen samples from two completely different areas using neutron activation analysis. Only short- and medium-lived irradiations were carried out. Satisfactory results were obtained for most of the elements identified and quantified. (author)

  7. Investigations on landmine detection by neutron-based techniques

    Energy Technology Data Exchange (ETDEWEB)

    Csikai, J. E-mail: csikai@delfin.klte.hu; Doczi, R.; Kiraly, B

    2004-07-01

    Principles and techniques of some neutron-based methods used to identify the antipersonnel landmines (APMs) are discussed. New results have been achieved in the field of neutron reflection, transmission, scattering and reaction techniques. Some conclusions are as follows: The neutron hand-held detector is suitable for the observation of anomaly caused by a DLM2-like sample in different soils with a scanning speed of 1 m{sup 2}/1.5 min; the reflection cross section of thermal neutrons rendered the determination of equivalent thickness of different soil components possible; a simple method was developed for the determination of the thermal neutron flux perturbation factor needed for multi-elemental analysis of bulky samples; unfolded spectra of elastically backscattered neutrons using broad-spectrum sources render the identification of APMs possible; the knowledge of leakage spectra of different source neutrons is indispensable for the determination of the differential and integrated reaction rates and through it the dimension of the interrogated volume; the precise determination of the C/O atom fraction requires the investigations on the angular distribution of the 6.13 MeV gamma-ray emitted in the {sup 16}O(n,n'{gamma}) reaction. These results, in addition to the identification of landmines, render the improvement of the non-intrusive neutron methods possible.

  8. Measurement of epithermal neutrons by a coherent demodulation technique

    CERN Document Server

    Horiuchi, N; Takahashi, H; Kobayashi, H; Harasawa, S

    2000-01-01

    Epithermal neutrons have been measured using a neutron dosimeter via a coherent demodulation technique. This dosimeter consists of CsI(Tl)-photodiode scintillation detectors, four of which are coupled to neutron-gamma converting foils of various sizes. Neutron-gamma converting foils of In, Au and Co materials were used, each of which has a large capture cross section which peaks in the epithermal neutron energy region. The type of foil was selected according to the material properties that best correspond to the energy of the epithermal neutrons to be measured. In addition, the proposed technique was applied using Au-foils in order to measure the Cd ratio. The validity of the proposed technique was examined using an sup 2 sup 4 sup 1 Am-Be source placed in a testing stack of polyethylene blocks, and the results were compared with the theoretical values calculated by the Monte Carlo calculation. Finally, the dosimeter was applied for measuring epithermal neutrons and the Cd ratio in an experimental beam-tube o...

  9. Principles and applications of neutron based inspection techniques

    International Nuclear Information System (INIS)

    Neutron based explosive inspection systems can detect a wide variety of substances of importance, for a variety of purposes from national security threats (e.g., nuclear materials, explosives, narcotics) to customs duties, shipment control and validation, and for protection of the environment. The inspection is generally founded on the nuclear interactions of the neutrons with the various nuclides present and the detection of resultant characteristic emissions. These can be discrete gamma lines resulting from the thermal (n,γ) neutron capture process or inelastic neutron scattering (n,n'γ) occurring with fast neutrons. The two types of reactions are generally complementary. The capture process provides energetic and highly penetrating gamma rays in most inorganic substances and in hydrogen, while fast neutron inelastic scattering provides relatively strong gamma-ray signatures in light elements such as carbon and oxygen. In some specific important cases, though, unique signatures are provided by the neutron capture process in light elements such as nitrogen, where unusually high energy gamma rays are produced. This forms the basis for key explosive detection techniques. The detection of nuclear materials, both fissionable (e.g., 238U) and fissile (e.g., 235U), are generally based on the fissions induced by the probing neutrons and detecting one or more of the unique signatures of the fission process. These include prompt and delayed neutrons and prompt and delayed gamma rays. These signatures are not discrete in energy (typically they are continua) but temporally and energetically significantly different from the background, thus making them readily distinguishable. The penetrability of fast neutrons as probes and the gamma rays and fission neutrons as signatures make neutron interrogation applicable for large conveyances such as cars, trucks and marine containers. The neutron-based techniques can be used in a variety of scenarios and operational modes. They can

  10. Principles and applications of neutron based inspection techniques

    International Nuclear Information System (INIS)

    Neutron based explosive inspection systems can detect a wide variety of substances of importance for a variety of purposes from national security threats (e.g., nuclear materials, explosives, narcotics) to customs dutiable goods, to hazardous substances to protect the environment. The inspection is generally founded on the nuclear interactions of the neutrons with the various nuclides present and the detection of resultant characteristic emissions. These can be discrete γ lines resulting from the thermal (n, γ) neutron capture process or inelastic neutron scattering (n, n'γ) occurring with fast neutrons. The two types of reactions are generally complementary. The capture process provides energetic and highly penetrating γ rays in most inorganic substances and hydrogen. Fast neutrons inelastic scattering provide relatively strong γ-ray signatures in light elements such as carbon and oxygen. In some specific important cases, unique signatures are provided by the neutron (n, γ) process in light elements such as nitrogen, where unusually high-energy γ rays are produced. This forms the basis for key explosive detection techniques. The detection of nuclear materials, both fissionable (e.g., 238U) and fissile (e.g., 235U), is generally based on the fissions induced by the probing neutrons and detecting one or more of the unique signatures of the fission process. These include prompt and delayed neutrons and prompt and delayed γ rays. These signatures are not discrete in energy (typically they are continua) but temporally and energetically significantly different from the background, thus making them readily distinguishable. The penetrability of fast neutrons as probes, and the γ rays and fission neutrons as signatures makes neutron interrogation applicable to the inspection of large conveyances such as cars, trucks, and marine containers. Neutron based inspection techniques have a broad applications. They can be used as stand-alone for complete scans of objects

  11. Exploratory studies on neutron radiography with a small neutron source using a nuclear scintillation imaging technique

    International Nuclear Information System (INIS)

    Neutron radiography based on mobile neutron sources need optimum utilization of available neutron fluxes which are usually lower compared to those available from reactors. For optimum utilization of such low flux devices, a sensitive neutron imaging technique is required. Such a neutron imaging system based on a Li6F-ZnS scintillator screen has been developed using a pair of image intensifier tubes and a charge coupled device. This detector system has been employed to study the feasibility of neutron radiography using low neutron fluences. The main feature of this imaging system is its ability to detect individual neutron scintillation events with a higher degree of spatial resolution. In order to test the efficiency of this imaging system, a small scale moderator-collimator assembly was designed using a Pu-Be neutron source of strength ∼2.107 n/s. Details of this imaging system and results of some exploratory experiments for low fluence neutron imaging are presented in this paper. (orig.)

  12. A new bridge technique for neutron tomography and diffraction measurements

    Energy Technology Data Exchange (ETDEWEB)

    Burca, G., E-mail: G.Burca@open.ac.uk [Materials Engineering, Open University, Milton Keynes, MK7 6AA (United Kingdom); James, J.A. [Materials Engineering, Open University, Milton Keynes, MK7 6AA (United Kingdom); Kockelmann, W. [ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, OX11 0QX (United Kingdom); Fitzpatrick, M.E. [Materials Engineering, Open University, Milton Keynes, MK7 6AA (United Kingdom); Zhang, S.Y. [ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, OX11 0QX (United Kingdom); Hovind, J. [Paul Scherrer Institute (PSI), CH-5232, Villigen (Switzerland); Langh, R. van [Delft University of Technology, Department of Materials Science, Faculty 3mE, Mekelweg 2, 2628 CD Delft (Netherlands); Rijksmuseum Amsterdam, P.O. Box 74888, 1070 DN Amsterdam (Netherlands)

    2011-09-21

    An attractive feature of neutron techniques is the ability to identify hidden materials and structures inside engineering components and objects of art and archaeology. Bearing this in mind we are investigating a new technique, 'Tomography Driven Diffraction' (TDD), that exploits tomography data to guide diffraction experiments on samples with complex structures and shapes. The technique can be used utilising combinations of individual tomography and diffraction instruments, such as NEUTRA (PSI, CH) and ENGIN-X (ISIS, UK), but is also suitable for new combined imaging and diffraction instruments such as the JEEP synchrotron engineering instrument (DIAMOND, UK) and the proposed IMAT neutron imaging and diffraction instrument (ISIS, UK).

  13. A new bridge technique for neutron tomography and diffraction measurements

    International Nuclear Information System (INIS)

    An attractive feature of neutron techniques is the ability to identify hidden materials and structures inside engineering components and objects of art and archaeology. Bearing this in mind we are investigating a new technique, 'Tomography Driven Diffraction' (TDD), that exploits tomography data to guide diffraction experiments on samples with complex structures and shapes. The technique can be used utilising combinations of individual tomography and diffraction instruments, such as NEUTRA (PSI, CH) and ENGIN-X (ISIS, UK), but is also suitable for new combined imaging and diffraction instruments such as the JEEP synchrotron engineering instrument (DIAMOND, UK) and the proposed IMAT neutron imaging and diffraction instrument (ISIS, UK).

  14. New volumetric technique for calibrating neutron probes

    International Nuclear Information System (INIS)

    Studies in laboratory conditions were carried out to determine neutron calibration curves. Soils were packer in barrels to attain values of bulk density similar to those in the field. A mariotte reservoir supplies water to the barels in a way that keeps a water table of 10 cm. A water flow is established from this saturated region to the top of the barrel. The water depth is correlated to the numerical integration of the count rate with depth during the process of capillary tise. The coefficient of determination was 0.999. The calibration curve was independent of the initial misture contents of the soil profile. (author)

  15. Deep inelastic scattering: photon and neutron complementary techniques

    International Nuclear Information System (INIS)

    The development of pulsed neutron sources for inelastic scattering has revitalised interest in the study of atomic momentum distributions in condensed matter. The experimental techniques currently employed are briefly reviewed together with the complementary methods used to study electron momentum distributions using inelastic photon (Compton) scattering. Both the experimental and theoretical developments are compared and contrasted and the future of neutron 'Compton' scattering briefly outlined. (author)

  16. Co-ordinated research project on validation and application of plants as biomonitors of trace element atmospheric pollution, analyzed by nuclear and related techniques. Report on the second research co-ordination meeting

    International Nuclear Information System (INIS)

    Environmental pollution is a cause of ever increasing concern in the world. The UN Conference on Environment and Development (Rio, Brazil, 1992) reaffirmed the importance of protecting the environment within the context of sustainable development. Arising out of this conference, the Rio Agenda 21 declaration called for a number of nationally determined action programmes, with international assistance and co-ordination under 'Capacity 21', concerning environmental monitoring and assessment, including the use of biological markers. Biomonitoring is an appropriate tool for assessing the levels of air pollution. In several developed countries biomonitoring is used on a regular basis for such surveys. Application of biomonitors has several advantages compared to the use of direct measurements of contaminants, related primarily to the permanent and common occurrence in the field, the ease of sampling and trace element accumulation. Furthermore, biomonitors provide a measure of integrated exposure over an extended period of time, are present in remote areas and no expensive technical equipment is involved in collecting them. Suitably chosen biomonitors accumulate contaminants over certain periods of time, concentrate them, thus allowing more reliable analytical measurements. Simple and cheap sampling procedures (in contrast to direct measurements) allow a very large number of sites to be included in the same survey, permitting detailed geographical patterns to be drawn. In combination with the specimen banking (long-term storage) of selected samples, biomonitoring can be an effective tool for pollutant mapping and trend monitoring by real time and retrospective analysis. By application of appropriate statistical tools, information can also be obtained on the type and location of pollution sources as well as on the short, medium and long range trans-boundary transport of environmental pollutants. In Europe, nuclear and related analytical techniques have been shown to be

  17. The efficiency of tobacco Bel-W3 and native species for ozone biomonitoring in subtropical climate, as revealed by histo-cytochemical techniques

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Edenise S., E-mail: ealves@ibot.sp.gov.br [Instituto de Botanica, Caixa Postal 3005, 01061-970 Sao Paulo, SP (Brazil); Moura, Barbara B., E-mail: bmourabio@gmail.com [Instituto de Botanica, Caixa Postal 3005, 01061-970 Sao Paulo, SP (Brazil); Pedroso, Andrea N.V., E-mail: andreanvpedroso@gmail.com [Instituto de Botanica, Caixa Postal 3005, 01061-970 Sao Paulo, SP (Brazil); Tresmondi, Fernanda, E-mail: ftresmondi@gmail.com [Instituto de Botanica, Caixa Postal 3005, 01061-970 Sao Paulo, SP (Brazil); Domingos, Marisa, E-mail: mmingos@superig.com.br [Instituto de Botanica, Caixa Postal 3005, 01061-970 Sao Paulo, SP (Brazil)

    2011-12-15

    We aimed to verify whether hydrogen peroxide (H{sub 2}O{sub 2}) accumulation and cell death are detected early in three bioindicators of ozone (O{sub 3}), Nicotiana tabacum 'Bel-W3', Ipomoea nil 'Scarlet O'Hara' and Psidium guajava 'Paluma', and whether environmental factors also affect those microscopic markers. The three species were exposed to chronic levels of O{sub 3} in a subtropical area and a histo-cytochemical technique that combines 3,3'-diaminobenzidine (DAB) with Evans blue staining was used in the assessments. The three species accumulated H{sub 2}O{sub 2}, but a positive correlation with O{sub 3} concentration was only observed in N. tabacum. A positive correlation between O{sub 3} and cellular death was also observed in N. tabacum. In I. nil and P. guajava, environmental factors were responsible for symptoms at the microscopic level, especially in P. guajava. We conclude that the most appropriate and least appropriate bioindicator plant for O{sub 3} monitoring in the subtropics are N. tabacum 'Bel-W3' and P. guajava 'Paluma', respectively. - Highlights: > H{sub 2}O{sub 2} and cell death occur in response to O{sub 3} and other stressful factors. > H{sub 2}O{sub 2} can be detected by DAB and cell death by Evans blue staining. > These techniques contribute for analysis of susceptible bioindicator species. > H{sub 2}O{sub 2} and cell death were explained by high levels of O{sub 3} in N. tabacum 'Bel-W3'. > N. tabacum is the most appropriate plant for monitoring in subtropics. - Nicotiana tabacum 'Bel-W3' is better than native species for O{sub 3} biomonitoring in the subtropics, as revealed by histo-cytochemical techniques.

  18. Elemental analysis of brazing alloy samples by neutron activation technique

    International Nuclear Information System (INIS)

    Two brazing alloy samples (C P2 and C P3) have been investigated by Neutron activation analysis (NAA) technique in order to identify and estimate their constituent elements. The pneumatic irradiation rabbit system (PIRS), installed at the first egyptian research reactor (ETRR-1) was used for short-time irradiation (30 s) with a thermal neutron flux of 1.6 x 1011 n/cm2/s in the reactor reflector, where the thermal to epithermal neutron flux ratio is 106. Long-time irradiation (48 hours) was performed at reactor core periphery with thermal neutron flux of 3.34 x 1012 n/cm2/s, and thermal to epithermal neutron flux ratio of 79. Activation by epithermal neutrons was taken into account for the (1/v) and resonance neutron absorption in both methods. A hyper pure germanium detection system was used for gamma-ray acquisitions. The concentration values of Al, Cr, Fe, Co, Cu, Zn, Se, Ag and Sb were estimated as percentages of the sample weight and compared with reported values. 1 tab

  19. Optimization of Neutron Beam Techniques for Haracterization of Structural Materials

    International Nuclear Information System (INIS)

    The result of the activities on the CRP project titled: Optimization of Neutron Beam Techniques for Characterization of Structural Materials has been reported. The activities consist of individual project which was proposed at the beginning of the project and collaborative works which is jointly carried out with the other members of the CRP. The individual project which is mainly focused on the optimization of the neutron diffractometer and neutron radiography has been sucessfully completed. The collaborative works which are mainly targeted to perform Round Robin exercise using VAMAS sample for neutron diffractometer and standard samples for tomography obtained from PSI have been carried out sucessfully. However, the texture measurement on Al alloys, applying data correction was not sucessfully achieved since the proper standard sample is not available and this is still needed for the the future plan. (author)

  20. Temperature variation studies using neutron diffraction technique

    International Nuclear Information System (INIS)

    Neutron diffraction experiments have been carried out on liquid heavy water in the temperature ranges -140C to 360C, using the D4B diffractometer at the Institute Laue-Langevin, Grenoble, France. Data have been collected to a high statistical accuracy out to large magnitude of scattering Vector, Q. A detailed analysis of the data in super-cooled liquid phase only is presented here. A first-order difference function ΔSM(Q,T)∼DM(Q,T) method has been used to determine the changes in the molecular structure factor of heavy water with temperature. Fourier transformation of ΔDM(Q,T) gives the corresponding changes in the real-space distribution functions, ΔdL(r,T). The result obtained is in good agreement with previous observations from an earlier experiment and gives a more precise indication of the structure variations. The present analysis shows that the inter-molecular OD and DD separations increase as the temperature changes from 110C, which corresponds to maximum density of liquid D2O. The variation in the hydrogen-bond configurations for the super-cooled liquid may be explained by the present of 'bifuracted' hydrogen-bonds. (author)

  1. Measurement of 14.8 MeV neutron flux of a neutron generator using neutron activation technique

    International Nuclear Information System (INIS)

    Fast neutron flux (14.8 MeV) of a neutron generator has been measured by activation technique. The measurements performed using Cu and Ni threshold detectors. 62Cu and 57Ni were produced through 63Cu(n,2n)62Cu and 58Ni (n,2n)57Ni reactions. They decay by emitting 511 keV and 1377 keV gamma rays. respectively. The half life of 62Cu is 9.74min and that of 57Ni is 36 hours. The flux of neutron has been calculated by measuring the activity after the irradiation time. Gamma spectroscopy of the activated foils was performed using a HPGe detector. By employing this technique the neutron flux of 2.64 107±3% n/s was obtained for 60 μA deuteron of 110 keV energy, bombarding a solid target of 3H

  2. Tagging of D-D and D-T neutrons using associated particle technique at Purnima Neutron Generator facility, India

    International Nuclear Information System (INIS)

    Neutron based detection system are being actively explored worldwide as a confirmatory tool for cargo inspection. Fast neutron based techniques are used to detect illicit material by detecting the neutron induced characteristic gamma-ray. The associated particle technique improves the signal-to-noise ratio by selecting the signals only from a specific location inside a large matrix

  3. Neutron noise analysis techniques in nuclear power reactors

    International Nuclear Information System (INIS)

    The main techniques used in neutron noise analysis of BWR and PWR nuclear reactors are reviewed. Several applications such as control of vibrations in both reactor types, determination of two phase flow parameters in BWR and stability control in BWR are discussed with some detail. The paper contains many experimental results obtained by the main author of this paper. (author)

  4. Neutron diffraction technique as a method for material studies

    International Nuclear Information System (INIS)

    The Morocco's first Nuclear Research has been constructed in CNESTEN. The reactor divergence has been tested, and the nominal power of 2MW was successfully achieved. The reactor has 4 beam ports two of them are projected for neutron scattering. Such technique allows studying the crystallographic and magnetic structures of materials using the thermal neutrons produced in the reactor. the powder diffractometer has been designed. Component reception and installation procedures are in progress. The second experiment consists on small angle neutron scattering that allows the study of soft matter and polymers in the range of 1-50 nm. The third technique that can complete the two previous is the 4-circle neutron spectrometry which is designed mainly to study structural properties of the mono-crystalline material and texture.This technique is complementary to the X-ray diffraction already available in CNESTEN. Some applications of this technique are: --to determine the crystallographic and magnetic structure of polycrystalline materials.-- to study the texture in metals and alloys.-- to perform holography measurement

  5. High-resolution neutrons diffraction techniques for strain scanning

    Czech Academy of Sciences Publication Activity Database

    Mikula, Pavol; Vrána, Miroslav; Lukáš, Petr; Wagner, V.

    Dordrecht : Kluwer Academic Publishers, 2002 - (Gdoutos, E.), s. 457-466 ISBN 1-4020-0683-7 R&D Projects: GA ČR GV202/97/K038; GA AV ČR IAA1048003 Keywords : high-resolution * neutron diffraction techniques * Bragg diffraction optics Subject RIV: BM - Solid Matter Physics ; Magnetism

  6. Synchrotron radiation, neutron, and mass spectrometry techniques at user facilities

    OpenAIRE

    Sutton, S. R.; Caffee, M. W.; Dove, M. T.

    2006-01-01

    User research facilities around the world offer tremendous opportunities for scientific experimentation by members of the Earth science community. Synchrotron radiation sources, neutron sources, mass spectrometers, and others represent a powerful force in tackling complex scientific problems. In these techniques, Earth materials are bombarded with beams of ions, subatomic particles and/or photons to learn the secr...

  7. Local variances in biomonitoring

    International Nuclear Information System (INIS)

    The present study deals with the (larger-scaled) biomonitoring survey and specifically focuses on the sampling site. In most surveys, the sampling site is simply selected or defined as a spot of (geographical) dimensions which is small relative to the dimensions of the total survey area. Implicitly it is assumed that the sampling site is essentially homogeneous with respect to the investigated variation in survey parameters. As such, the sampling site is mostly regarded as 'the basic unit' of the survey. As a logical consequence, the local (sampling site) variance should also be seen as a basic and important characteristic of the survey. During the study, work is carried out to gain more knowledge of the local variance. Multiple sampling is carried out at a specific site (tree bark, mosses, soils), multi-elemental analyses are carried out by NAA, and local variances are investigated by conventional statistics, factor analytical techniques, and bootstrapping. Consequences of the outcomes are discussed in the context of sampling, sample handling and survey quality. (author)

  8. Lichens as biomonitor and INAA as analytical technique: a very effective formula for trace elements atmospheric pollution studies

    International Nuclear Information System (INIS)

    In this work, a preliminary investigation employing epiphytic lichens and Instrumental Neutron Activation Analysis (INAA) was carried out to evaluate the trace elements (TE) distribution in different areas of an Alpine region in north Italy characterized by the presence of many wool industrial settlements. Air particulate matter and soils samples were collected and analyzed for the determination of more than 25 TE. These results gave information on the actual concentrations in ng/m3 of the TE in the air and allowed the determination of their Enrichment Factors (EFs) calculated from the analysis of the soils and normalized using the concentration of scandium as reference natural element. In the same site, different epiphytic lichens and surrounding soils samples were collected too and, following the same procedure, analyzed for the determination of the trace elements and for the calculation of the corresponding EFs. The comparison between the EFs obtained from the air particulate and the lichens made it possible the verifying if both series of samples (air particulate and lichens) could give similar EFs values for those elements considered of anthropic origin; obtaining information about the bioaccumulation ability of the different lichen species for these pollutant elements; selecting the lichen species that could be used as monitors for the area under investigation

  9. Neutrons for Catalysis: A Workshop on Neutron Scattering Techniques for Studies in Catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Overbury, Steven {Steve} H [ORNL; Coates, Leighton [ORNL; Herwig, Kenneth W [ORNL; Kidder, Michelle [ORNL

    2011-10-01

    This report summarizes the Workshop on Neutron Scattering Techniques for Studies in Catalysis, held at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) on September 16 and 17, 2010. The goal of the Workshop was to bring experts in heterogeneous catalysis and biocatalysis together with neutron scattering experimenters to identify ways to attack new problems, especially Grand Challenge problems in catalysis, using neutron scattering. The Workshop locale was motivated by the neutron capabilities at ORNL, including the High Flux Isotope Reactor (HFIR) and the new and developing instrumentation at the SNS. Approximately 90 researchers met for 1 1/2 days with oral presentations and breakout sessions. Oral presentations were divided into five topical sessions aimed at a discussion of Grand Challenge problems in catalysis, dynamics studies, structure characterization, biocatalysis, and computational methods. Eleven internationally known invited experts spoke in these sessions. The Workshop was intended both to educate catalyst experts about the methods and possibilities of neutron methods and to educate the neutron community about the methods and scientific challenges in catalysis. Above all, it was intended to inspire new research ideas among the attendees. All attendees were asked to participate in one or more of three breakout sessions to share ideas and propose new experiments that could be performed using the ORNL neutron facilities. The Workshop was expected to lead to proposals for beam time at either the HFIR or the SNS; therefore, it was expected that each breakout session would identify a few experiments or proof-of-principle experiments and a leader who would pursue a proposal after the Workshop. Also, a refereed review article will be submitted to a prominent journal to present research and ideas illustrating the benefits and possibilities of neutron methods for catalysis research.

  10. Neutrons for Catalysis: A Workshop on Neutron Scattering Techniques for Studies in Catalysis

    International Nuclear Information System (INIS)

    This report summarizes the Workshop on Neutron Scattering Techniques for Studies in Catalysis, held at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) on September 16 and 17, 2010. The goal of the Workshop was to bring experts in heterogeneous catalysis and biocatalysis together with neutron scattering experimenters to identify ways to attack new problems, especially Grand Challenge problems in catalysis, using neutron scattering. The Workshop locale was motivated by the neutron capabilities at ORNL, including the High Flux Isotope Reactor (HFIR) and the new and developing instrumentation at the SNS. Approximately 90 researchers met for 1 1/2 days with oral presentations and breakout sessions. Oral presentations were divided into five topical sessions aimed at a discussion of Grand Challenge problems in catalysis, dynamics studies, structure characterization, biocatalysis, and computational methods. Eleven internationally known invited experts spoke in these sessions. The Workshop was intended both to educate catalyst experts about the methods and possibilities of neutron methods and to educate the neutron community about the methods and scientific challenges in catalysis. Above all, it was intended to inspire new research ideas among the attendees. All attendees were asked to participate in one or more of three breakout sessions to share ideas and propose new experiments that could be performed using the ORNL neutron facilities. The Workshop was expected to lead to proposals for beam time at either the HFIR or the SNS; therefore, it was expected that each breakout session would identify a few experiments or proof-of-principle experiments and a leader who would pursue a proposal after the Workshop. Also, a refereed review article will be submitted to a prominent journal to present research and ideas illustrating the benefits and possibilities of neutron methods for catalysis research.

  11. Radiative neutron capture as a counting technique at pulsed spallation neutron sources: a review of current progress.

    Science.gov (United States)

    Schooneveld, E M; Pietropaolo, A; Andreani, C; Perelli Cippo, E; Rhodes, N J; Senesi, R; Tardocchi, M; Gorini, G

    2016-09-01

    Neutron scattering techniques are attracting an increasing interest from scientists in various research fields, ranging from physics and chemistry to biology and archaeometry. The success of these neutron scattering applications is stimulated by the development of higher performance instrumentation. The development of new techniques and concepts, including radiative capture based neutron detection, is therefore a key issue to be addressed. Radiative capture based neutron detectors utilize the emission of prompt gamma rays after neutron absorption in a suitable isotope and the detection of those gammas by a photon counter. They can be used as simple counters in the thermal region and (simultaneously) as energy selector and counters for neutrons in the eV energy region. Several years of extensive development have made eV neutron spectrometers operating in the so-called resonance detector spectrometer (RDS) configuration outperform their conventional counterparts. In fact, the VESUVIO spectrometer, a flagship instrument at ISIS serving a continuous user programme for eV inelastic neutron spectroscopy measurements, is operating in the RDS configuration since 2007. In this review, we discuss the physical mechanism underlying the RDS configuration and the development of associated instrumentation. A few successful neutron scattering experiments that utilize the radiative capture counting techniques will be presented together with the potential of this technique for thermal neutron diffraction measurements. We also outline possible improvements and future perspectives for radiative capture based neutron detectors in neutron scattering application at pulsed neutron sources. PMID:27502571

  12. Radiative neutron capture as a counting technique at pulsed spallation neutron sources: a review of current progress

    Science.gov (United States)

    Schooneveld, E. M.; Pietropaolo, A.; Andreani, C.; Perelli Cippo, E.; Rhodes, N. J.; Senesi, R.; Tardocchi, M.; Gorini, G.

    2016-09-01

    Neutron scattering techniques are attracting an increasing interest from scientists in various research fields, ranging from physics and chemistry to biology and archaeometry. The success of these neutron scattering applications is stimulated by the development of higher performance instrumentation. The development of new techniques and concepts, including radiative capture based neutron detection, is therefore a key issue to be addressed. Radiative capture based neutron detectors utilize the emission of prompt gamma rays after neutron absorption in a suitable isotope and the detection of those gammas by a photon counter. They can be used as simple counters in the thermal region and (simultaneously) as energy selector and counters for neutrons in the eV energy region. Several years of extensive development have made eV neutron spectrometers operating in the so-called resonance detector spectrometer (RDS) configuration outperform their conventional counterparts. In fact, the VESUVIO spectrometer, a flagship instrument at ISIS serving a continuous user programme for eV inelastic neutron spectroscopy measurements, is operating in the RDS configuration since 2007. In this review, we discuss the physical mechanism underlying the RDS configuration and the development of associated instrumentation. A few successful neutron scattering experiments that utilize the radiative capture counting techniques will be presented together with the potential of this technique for thermal neutron diffraction measurements. We also outline possible improvements and future perspectives for radiative capture based neutron detectors in neutron scattering application at pulsed neutron sources.

  13. Analysis of tree bark samples for air pollution biomonitoring of an urban area

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Ana Paula G.; Negri, Elnara M.; Saldiva, Paulo H.N., E-mail: paulista@usp.b [Universidade de Sao Paulo (USP), SP (Brazil). Faculdade de Medicina. Dept. de Patologia; Saiki, Mitiko; Scapin, Marcos A.; Ribeiro, Andreza P.; Salvador, Vera L., E-mail: mitiko@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    Air pollution is receiving much attention as a public health problem around the world due to its adverse health effects from exposures by urban populations. Within this context, the use of vegetal biomonitoring to evaluate air quality has been investigated throughout the world. Air pollutant levels are high in the city of Sao Paulo, SP, Brazil and being the vehicle emissions its main source. The aim of this study was to evaluate concentrations of As, Ba, Br, Ca, Co, Cr, Cu, Fe, Mn, Pb, S, Sb and Zn in tree bark samples used as biomonitor of urban air pollution. Concentrations of these elements were determined in barks collected in trees of the Ibirapuera Park, one of the biggest and most visited parks of the city of Sao Paulo city. Samples of tree barks were also collected in a site outside the city of Sao Paulo, in a rural area of Embu-Guacu, considered as a control site. The element concentrations were determined by the methods of Instrumental Neutron Activation Analysis (INAA) and of Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF). The findings of this study showed that tree bark samples may be used as biomonitors of urban air pollution in a micro scale, and both techniques, INAA and EDXRF, can be used to evaluate element concentrations in tree bark samples. (author)

  14. Analysis of tree bark samples for air pollution biomonitoring of an urban area

    International Nuclear Information System (INIS)

    Air pollution is receiving much attention as a public health problem around the world due to its adverse health effects from exposures by urban populations. Within this context, the use of vegetal biomonitoring to evaluate air quality has been investigated throughout the world. Air pollutant levels are high in the city of Sao Paulo, SP, Brazil and being the vehicle emissions its main source. The aim of this study was to evaluate concentrations of As, Ba, Br, Ca, Co, Cr, Cu, Fe, Mn, Pb, S, Sb and Zn in tree bark samples used as biomonitor of urban air pollution. Concentrations of these elements were determined in barks collected in trees of the Ibirapuera Park, one of the biggest and most visited parks of the city of Sao Paulo city. Samples of tree barks were also collected in a site outside the city of Sao Paulo, in a rural area of Embu-Guacu, considered as a control site. The element concentrations were determined by the methods of Instrumental Neutron Activation Analysis (INAA) and of Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF). The findings of this study showed that tree bark samples may be used as biomonitors of urban air pollution in a micro scale, and both techniques, INAA and EDXRF, can be used to evaluate element concentrations in tree bark samples. (author)

  15. NET European Network on Neutron Techniques Standardization for Structural Integrity

    International Nuclear Information System (INIS)

    Improved performance and safety of European energy production systems is essential for providing safe, clean and inexpensive electricity to the citizens of the enlarged EU. The state of the art in assessing internal stresses, micro-structure and defects in welded nuclear components -as well as their evolution due to complex thermo-mechanical loads and irradiation exposure -needs to be improved before relevant structural integrity assessment code requirements can safely become less conservative. This is valid for both experimental characterization techniques and predictive numerical algorithms. In the course of the last two decades neutron methods have proven to be excellent means for providing valuable information required in structural integrity assessment of advanced engineering applications. However, the European industry is hampered from broadly using neutron research due to lack of harmonised and standardized testing methods. 35 European major industrial and research/academic organizations have joined forces, under JRC coordination, to launch the NET European Network on Neutron Techniques Standardization for Structural Integrity in May 2002. The NET collaborative research initiative aims at further development and harmonisation of neutron scattering methods, in support of structural integrity assessment. This is pursued through a number of testing round robin campaigns on neutron diffraction and small angle neutron scattering - SANS and supported by data provided by other more conventional destructive and non-destructive methods, such as X-ray diffraction and deep and surface hole drilling. NET also strives to develop more reliable and harmonized simulation procedures for the prediction of residual stress and damage in steel welded power plant components. This is pursued through a number of computational round robin campaigns based on advanced FEM techniques, and on reliable data obtained by such novel and harmonized experimental methods. The final goal of

  16. Two-phase flow measurement by pulsed neutron activation techniques

    International Nuclear Information System (INIS)

    The Pulsed Neutron Activation (PNA) technique for measuring the mass flow velocity and the average density of two-phase mixtures is described. PNA equipment can be easily installed at different loops, and PNA techniques are non-intrusive and independent of flow regimes. These features of the PNA technique make it suitable for in-situ measurement of two-phase flows, and for calibration of more conventional two-phase flow measurement devices. Analytic relations governing the various PNA methods are derived. The equipment and procedures used in the first air-water flow measurement by PNA techniques are discussed, and recommendations are made for improvement of future tests. In the present test, the mass flow velocity was determined with an accuracy of 2%, and average densities were measured down to 0.08 g/cm3 with an accuracy of 0.04 g/cm3. Both the accuracy of the mass flow velocity measurement and the lower limit of the density measurement are functions of the injected activity and of the total number of counts. By using a stronger neutron source and a larger number of detectors, the measurable density can be decreased by a factor of 12 to .007 g/cm3 for 12.5 cm pipes, and to even lower ranges for larger pipes

  17. Environmental lichenology: Biomonitoring of trace element air pollution

    International Nuclear Information System (INIS)

    The review of application of lichens and mosses as biomonitors of air pollution have been presented. The neutron activation analysis and atomic absorption spectroscopy have been used for trace element content determination in lichens and mosses taken from different regions of Europe

  18. Analysis of Protein in Soybean by Neutron Activation Technique

    International Nuclear Information System (INIS)

    Nitrogen content in soybean was studied by using Neutron Activation Analysis technique through fast neutron at the flux of 2.5 * 1011 n/cm2. sec in the CA-3 out-core irradiation tube of the Thai Research Reactor-1/Modification 1 (TRR-1/M1, Triga Mark 3 type). By measuring gamma ray of 511 keV from 13N of the nuclear reaction, 14N(n, 2n)13N caused by the annihilation of positron disintegrated, the semi-conductor detector (HPGe) was connected with the multi-channel analyzer (MCA) and monitor to display the spectrum range. NH4NO3 was used as the standard for the analysis. The inaccuracy of the analysis caused by other radioisotopes, i.e. potassium, phosphorus and reaction from recoiled proton scattering in soybean was corrected. The data of 27 samples analyzed by neutron activation showed no significant difference in the nitrogen content. The average nitrogen content of all the soybean samples is 7.02% equivalent to protein content of 43.88%

  19. Neutron capture strategy and technique developments for GNEP

    Energy Technology Data Exchange (ETDEWEB)

    Couture, Aaron Joseph [Los Alamos National Laboratory

    2008-01-01

    The initial three years of neutron capture measurements have been very successful in providing data for the Advanced Fuel Cycle Initiative/Global Nuclear Energy Partnership (AFCI/GNEP) program. Now that the most straightforward measurements have been completed, additional technical challenges face future measurements. In particular, techniques are needed to perform measurements that exhibit at least one of three major problems -- large fission:capture ratios, large capture:capture ratios, and high intrinsic activity samples. This paper will set forward a plan for attacking these technical challenges and moving forward with future measurements.

  20. Air Pollution Studies in Central Russia (Tver and Yaroslavl Regions) Using the Moss Biomonitoring Technique and Neutron Activation Analysis

    CERN Document Server

    Ermakova, E V; Pavlov, S S; Povtoreiko, E A; Steinnes, E; Cheremisina, Ye N

    2003-01-01

    Data of 34 elements, including heavy metals, halogens, rare-earth elements, U, and Th in 140 moss samples, collected in central Russia (Tver and Yaroslavl regions and the northern part of Moscow Region) in 2000-2002, are presented. Factor analysis with VARIMAX rotation was applied to identify possible sources of the elements determined in the mosses. The seven resulting factors represent crust, vegetation and anthropogenic components in the moss. Some of the factors were interpreted as being associated with ferrous smelters (Fe, Zn, Sb, Ta); combination of non-ferrous smelters and other industries (Mn, Co, Mo, Cr, Ni, W); an oil-refining plant, and oil combustion at the thermal power plant (V, Ni). The geographical distribution patterns of the factor scores are also presented. The dependency equations of elemental content in mosses versus distance from the source are derived.

  1. Multielement atmospheric deposition study in Croatia using moss biomonitoring, NAA, AAS and GIS technologies

    International Nuclear Information System (INIS)

    For the first time the moss biomonitoring technique and two complementary analytical techniques - neutron activation analysis (NAA) and atomic absorption spectrometry (AAS) - were applied to study multielement atmospheric deposition in the Republic of Croatia. Moss samples were collected during the summer 2006 from 98 sites evenly distributed over the country. Sampling was performed in accordance with the LRTAP Convention - ICP Vegetation protocol and sampling strategy of the European Programme on Biomonitoring of Heavy Metal Atmospheric Deposition. Conventional and epithermal neutron activation analyses made it possible to determine concentrations of 41 elements including key heavy metals such as Pb, Cd, Hg, and Cu determined by AAS. Principal component analysis (factor analysis with VARIMAX rotation) was applied to distinguish elements mainly of anthropogenic origin from those predominantly originating from natural sources. Geographical distribution maps of the elements over the sampled territory were constructed using GIS technology. The median values for Croatia are consistent with the corresponding values for all Europe for most elements. It was shown that the Adriatic coastline of Croatia may be considered as an environmentally pristine area. This study was conducted for providing reliable assessment of air quality throughout Croatia and producing information needed for better identification of pollution sources and improving the potential for assessing environmental and health risks in Croatia associated with toxic metals

  2. Simultaneous and integrated neutron-based techniques for material analysis of a metallic ancient flute

    Science.gov (United States)

    Festa, G.; Pietropaolo, A.; Grazzi, F.; Sutton, L. F.; Scherillo, A.; Bognetti, L.; Bini, A.; Barzagli, E.; Schooneveld, E.; Andreani, C.

    2013-09-01

    A metallic 19th century flute was studied by means of integrated and simultaneous neutron-based techniques: neutron diffraction, neutron radiative capture analysis and neutron radiography. This experiment follows benchmark measurements devoted to assessing the effectiveness of a multitask beamline concept for neutron-based investigation on materials. The aim of this study is to show the potential application of the approach using multiple and integrated neutron-based techniques for musical instruments. Such samples, in the broad scenario of cultural heritage, represent an exciting research field. They may represent an interesting link between different disciplines such as nuclear physics, metallurgy and acoustics.

  3. Design and techniques for fusion blanket neutronics experiments using an accelerator-based deuterium-tritium neutron source

    International Nuclear Information System (INIS)

    The experiments performed in the Japan Atomic Energy Research Institute/U.S. Department of Energy collaborative program on fusion blanket neutronics are designed with consideration of geometrical and material configurations. The general guide that is used to design the engineering-oriented neutronics experiment, which uses an accelerator-based 14-MeV neutron source, is discussed and compared with neutronics characteristics of the reactor models. Preparation of the experimental assembly, blanket materials, and the neutron source is described. A variety of techniques for measuring the nuclear parameters such as the tritium production rate are developed or introduced through the collaboration as a basis of the neutronics experiments. The features of these techniques are discussed with the experimental error and compared with each other. 25 refs., 15 figs., 4 tabs

  4. Lichens as biomonitors at indoor environments of primary schools

    International Nuclear Information System (INIS)

    A biomonitoring study, using transplanted lichens Flavoparmelia caperata, was conducted to assess the indoor air quality in primary schools in urban (Lisbon) and rural (Ponte de Sor) Portuguese sites. The lichens exposure period occurred between April and June 2010 and two types of environments of the primary schools were studied: classrooms and outdoor/courtyard. Afterwards, the lichen samples were processed and analyzed by instrumental neutron activation analysis (INAA) to assess a total of 20 chemical elements. Accumulated elements in the exposed lichens were assessed and enrichment factors (EF) were determined. Indoor and outdoor biomonitoring results were compared to evaluate how biomonitors (as lichens) react at indoor environments and to assess the type of pollutants that are prevalent in those environments. (author)

  5. Air Pollution Studies in Opole Region, Poland, using the Moss Biomonitoring and INAA

    Science.gov (United States)

    Korzekwa, S.; Pankratova, Yu. S.; Frontasyeva, M. V.

    2007-11-01

    Biomonitoring of heavy metal atmospheric deposition with terrestrial moss is a well established technique for environmental studies. Moss samples of Hylocomium splendens and Pleurozium schreberi have been collected around the city of Opole. A total of 34 elements including heavy metals and rare earths have been determined by instrumental neutron activation analysis (INAA) using epithermal neutrons at the IBR-2 reactor of the Joint Institute for Nuclear Research. We observe pronounced contamination of the sampled area with pollutants such as As, Sb, V, Ni, Mo, etc. at levels similar to those in the neighboring industrial regions. These results evidences long-range atmospheric transport of pollutants along with the influence of local pollution sources.

  6. Neutron scattering techniques in the examination of recycled aggregate concrete

    International Nuclear Information System (INIS)

    Full text: Researchers at Swinburne University of Technology (SUT) have undertaken a research project aiming initially at better understanding the effects of any chemical impurities in Recycled Concrete Aggregate (RCA) on the microstructure development of Recycled Aggregate Concrete (RAC). Furthermore, a porosity of RCA and RAC and its effect on the acoustic performance and mechanical properties is being investigated. A number of conventional tests have been employed to examine the porosity of the aggregate and concrete made from RCA ranging from Volume of Permeable Voids test, through nitrogen adsorption to scanning electron microscopy. These tests are performed at SUT to characterise pores structure including pore size and volume as well as their surface area. The preparation of samples differs for the various tests, and this is a main reason contributing to inconsistencies in the results from these tests. None-the-less the results indicate strong positive correlation of inherent and purposely introduced porosity in RAC to its sound absorption capacities. Some inconsistency in the results is also due to the complexity of concrete itself compounded by the use of recycled material. However, the research has been granted a Grant from Australian Institute of Nuclear Science and Engineering (AINSE) which allows to conduct RAC examination using Small Angle Neutron Scattering (SANS). This neutron scattering technique characterises pore structure in a non-destructive manner. The results from this method should augment these obtained from conventional methods

  7. The behavior of moisture content in Durian after harvesting by neutron reflection and transmission techniques

    International Nuclear Information System (INIS)

    The study aimed at development of a neutron reflection and transmission technique to determine moisture content in Durian fruit as a function of time after harvesting. A system of a 3 mCi Am-Be neutron source with a BF3 detector as a neutron probe was developed. The results obtained were validated using weighting method

  8. Biomonitoring air pollution in Chile

    International Nuclear Information System (INIS)

    Full text: Chile, in general, and Santiago, its capital city, in particular, has serious air pollution problems mainly in winter time when the pollutants could reach dangerous levels which might be detrimental to older people and children. A project was undertaken within the framework of a Co-ordinated Research Programme (CRP) supported by the International Atomic Energy Agency (IAEA) to carry out a long term study on atmospheric air pollution in Chile using biomonitors. The present paper describes the activities carried out within this CRP. The lichens, collected in clean areas (native forests), were transplanted to selected sites in Santiago and exposed during three and six months. At a second stage, samples of Tillandsia recurvata were collected in the Metropolitan Area. All samples were carefully cleaned, using only clean plastic materials, milled at liquid nitrogen temperature, freeze dried, re-homogenized and stored at low temperature until analysis. The samples were mainly analysed by INAA, RNAA SS-AAS and ASV. As part of the routine QA/QC programme, analytical laboratories involved in the project participated in intercomparison runs organized by the IAEA for the determination of trace and minor elements in two lichens samples. From the data and its subsequent mapping over the area under study, it was possible to identify places exposed to higher amounts of some elements. Of interest are also the correlations between several elements, perhaps indicating a given source of pollutants. The results indicate the usefulness of biomonitoring air pollution using lichens and Tillandsias, which, jointly with multielemental analytical techniques, such as NAA, open the possibility to study extensive areas without the infrastructure needed for conventional APM sample collection and at reduced costs. (author)

  9. Non-destructive plant-nutrition analysis by neutron analysis by neutron activation and X-ray fluorescence techniques

    International Nuclear Information System (INIS)

    Non-destructive neutron activation and x-ray fluorescence techniques have been applied to the analysis of plant nutrients in soil. The advantages of these methods over the conventional ones have also been focussed. (author)

  10. Measurements of fusion neutron yields by neutron activation technique: Uncertainty due to the uncertainty on activation cross-sections

    International Nuclear Information System (INIS)

    The neutron activation technique is routinely used in fusion experiments to measure the neutron yields. This paper investigates the uncertainty on these measurements as due to the uncertainties on dosimetry and activation reactions. For this purpose, activation cross-sections were taken from the International Reactor Dosimetry and Fusion File (IRDFF-v1.05) in 640 groups ENDF-6 format for several reactions of interest for both 2.5 and 14 MeV neutrons. Activation coefficients (reaction rates) have been calculated using the neutron flux spectra at JET vacuum vessel, both for DD and DT plasmas, calculated by MCNP in the required 640-energy group format. The related uncertainties for the JET neutron spectra are evaluated as well using the covariance data available in the library. These uncertainties are in general small, but not negligible when high accuracy is required in the determination of the fusion neutron yields

  11. Use of the associated particle technique in the fast neutron spectroscopy

    International Nuclear Information System (INIS)

    Selecting a neutrons monoenergetic source it was found that the nuclear reaction D(d,n)3He can be used to measure nuclear sections and differentials in elastic nuclear reactions through the associated particle technique; the neutron beam energy is directly determined in time of flight spectrum of the neutron. The flux is determined by the number of 3He ions observed in the charged particle spectrum. The neutron flux can be increased increasing the solid angle of the neutrons beam in two magnitude orders according to the results of neutrons beam profile measures. (author)

  12. Inspection of an artificial heart by the neutron radiography technique

    International Nuclear Information System (INIS)

    The neutron radiography technique was employed to inspect an artificial heart prototype which is being developed to provide blood circulation for patients expecting heart transplant surgery. The radiographs have been obtained by the direct method with a gadolinium converter screen along with the double coated Kodak-AA emulsion film. The artificial heart consists of a flexible plastic membrane located inside a welded metallic cavity, which is employed for blood pumping purposes. The main objective of the present inspection was to identify possible damages in this plastic membrane, produced during the welding process of the metallic cavity. The obtained radiographs were digitized as well as analysed in a PC and the improved images clearly identify several damages in the plastic membrane, suggesting changes in the welding process

  13. Inspection of an artificial heart by the neutron radiography technique

    Science.gov (United States)

    Pugliesi, R.; Geraldo, L. P.; Andrade, M. L. G.; Menezes, M. O.,; Pereira, M. A. S.; Maizato, M. J. S.

    1999-11-01

    The neutron radiography technique was employed to inspect an artificial heart prototype which is being developed to provide blood circulation for patients expecting heart transplant surgery. The radiographs have been obtained by the direct method with a gadolinium converter screen along with the double coated Kodak-AA emulsion film. The artificial heart consists of a flexible plastic membrane located inside a welded metallic cavity, which is employed for blood pumping purposes. The main objective of the present inspection was to identify possible damages in this plastic membrane, produced during the welding process of the metallic cavity. The obtained radiographs were digitized as well as analysed in a PC and the improved images clearly identify several damages in the plastic membrane, suggesting changes in the welding process.

  14. Inspection of an artificial heart by the neutron radiography technique

    CERN Document Server

    Pugliesi, R; Andrade, M L G; Menezes, M O; Pereira, M A S; Maizato, M J S

    1999-01-01

    The neutron radiography technique was employed to inspect an artificial heart prototype which is being developed to provide blood circulation for patients expecting heart transplant surgery. The radiographs have been obtained by the direct method with a gadolinium converter screen along with the double coated Kodak-AA emulsion film. The artificial heart consists of a flexible plastic membrane located inside a welded metallic cavity, which is employed for blood pumping purposes. The main objective of the present inspection was to identify possible damages in this plastic membrane, produced during the welding process of the metallic cavity. The obtained radiographs were digitized as well as analysed in a PC and the improved images clearly identify several damages in the plastic membrane, suggesting changes in the welding process.

  15. Morphologic characterization of Mycobacterium marinum by neutron radiographic technique

    International Nuclear Information System (INIS)

    The genus Mycobacterium shares many characteristics with the genera Corynebacterium and Actinomyces, among which, similar genome content of bases Guanine-Cytosine and the production of branched long-chain fatty acids called mycolic acids should be enhanced. Mycobacteria are strict aerobic, considered weakly Gram-positive, rod-shaped microorganisms, not possessing flagella. They are intracellular infecting and proliferating in the interior of macrophages, they do not form spores, produce toxins or have capsule. Optimal growth temperature and rate are variable. The genus encompasses approximately 120 known species; however, the present study focuses the characterization of Mycobacterium marinum. This species is generally pathogenic causing deep skin infections. Colonies grow slowly at temperatures around 37 degree C. The aim of this study is to speed the process of M. Marinum morphologic characterization and, in the future, apply it to other species of Nontuberculous Mycobacteria (NTM. In relation to conventional microbiologic essays that usually demand 28 days for colony growth, nuclear testing, using the neutron radiography technique, prove to be much faster. The samples were initially sterilized at the Mycobacteria Laboratory/IMPPG/UFRJ using hypochlorite solution, gluta + formaldehyde and warmed distilled water, according conventional protocols. Then, they were incubated with sodium borate, deposited over CR-39 sheets, fixed with casein (only the first and third sample) and irradiated with a thermal neutron beam generated at the J-9 channel of the Argonauta reactor from the IEN/CNEN. To this end, the following parameters were optimized: incubation time, irradiation time and CR-39 developing time. The images registered in CR-39 were visualized with the help of a Nikon E-400 optical microscope and captured with a Cool pix 995 digital camera. The results showed that the technique produces enlarged images, making it easier the morphologic characterization of

  16. Morphologic characterization of Mycobacterium marinum by neutron radiographic technique

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jaqueline Michele da; Crispim, Verginia Reis, E-mail: vrcrispim@gmail.com [Universidade Federal do Rio de Janeiro (CT/UFRJ) Centro Tecnologico, Engenharia Nuclear, RJ (Brazil); Silva, Marlei Gomes da [Universidade Federal do Rio de Janeiro (CCS/UFRJ), Centro de Ciencias da Saude. Instituto de Microbiologia Professor Paulo de Goes (Brazil)

    2011-07-01

    The genus Mycobacterium shares many characteristics with the genera Corynebacterium and Actinomyces, among which, similar genome content of bases Guanine-Cytosine and the production of branched long-chain fatty acids called mycolic acids should be enhanced. Mycobacteria are strict aerobic, considered weakly Gram-positive, rod-shaped microorganisms, not possessing flagella. They are intracellular infecting and proliferating in the interior of macrophages, they do not form spores, produce toxins or have capsule. Optimal growth temperature and rate are variable. The genus encompasses approximately 120 known species; however, the present study focuses the characterization of Mycobacterium marinum. This species is generally pathogenic causing deep skin infections. Colonies grow slowly at temperatures around 37 degree C. The aim of this study is to speed the process of M. Marinum morphologic characterization and, in the future, apply it to other species of Nontuberculous Mycobacteria (NTM. In relation to conventional microbiologic essays that usually demand 28 days for colony growth, nuclear testing, using the neutron radiography technique, prove to be much faster. The samples were initially sterilized at the Mycobacteria Laboratory/IMPPG/UFRJ using hypochlorite solution, gluta + formaldehyde and warmed distilled water, according conventional protocols. Then, they were incubated with sodium borate, deposited over CR-39 sheets, fixed with casein (only the first and third sample) and irradiated with a thermal neutron beam generated at the J-9 channel of the Argonauta reactor from the IEN/CNEN. To this end, the following parameters were optimized: incubation time, irradiation time and CR-39 developing time. The images registered in CR-39 were visualized with the help of a Nikon E-400 optical microscope and captured with a Cool pix 995 digital camera. The results showed that the technique produces enlarged images, making it easier the morphologic characterization of

  17. An associated particle technique for absolute neutron counting efficiency determination

    International Nuclear Information System (INIS)

    The 7Li(p,n)7Be reaction has been used to produce neutrons with energies ranging from 8 to 13 MeV in order to measure the absolute neutron counting efficiency of a large NE213 scintillator by the associated particle method. Recoil 7Be nuclei were detected with a ΔE(gas)-E (solid) telescope in coincidence with neutrons. The method is suitable for neutron energies greater than 1.2MeV and could be applied to establish the neutron efficiency response of any detector

  18. Chemical weapons detection by fast neutron activation analysis techniques

    International Nuclear Information System (INIS)

    A neutron diagnostic experimental apparatus has been tested for nondestructive verification of sealed munitions. Designed to potentially satisfy a significant number of van-mobile requirements, this equipment is based on an easy to use industrial sealed tube neutron generator that interrogates the munitions of interest with 14 MeV neutrons. Gamma ray spectra are detected with a high purity germanium detector, especially shielded from neutrons and gamma ray background. A mobile shell holder has been used. Possible configurations allow the detection, in continuous or in pulsed modes, of gamma rays from neutron inelastic scattering, from thermal neutron capture, and from fast or thermal neutron activation. Tests on full scale sealed munitions with chemical simulants show that those with chlorine (old generation materials) are detectable in a few minutes, and those including phosphorus (new generation materials) in nearly the same time. (orig.)

  19. Bulk moisture determination in building materials by fast neutron/gamma technique

    International Nuclear Information System (INIS)

    Fast Neutron/Gamma Transmission technique has been improved to allow to measure moisture content in building materials. In order to improve fast neutron/gamma discrimination in the transmission system employing the NE-213 scintillation detector a pulse shape discrimination system was constructed at the CEADEN. A separate neutron/gamma detection approach was used with neutron transmission measurement using an Am-Be neutron source and a BF3 detector and gamma transmission measurement using a collimated 137Cs source and a NaI scintillator

  20. Determination of spallation neutron flux through spectral adjustment techniques

    Science.gov (United States)

    Mosby, M. A.; Engle, J. W.; Jackman, K. R.; Nortier, F. M.; Birnbaum, E. R.

    2016-08-01

    The Los Alamos Isotope Production Facility (IPF) creates medical isotopes using a proton beam impinged on a target stack. Spallation neutrons are created in the interaction of the beam with target. The use of these spallation neutrons to produce additional radionuclides has been proposed. However, the energy distribution and magnitude of the flux is not well understood. A modified SAND-II spectral adjustment routine has been used with radioactivation foils to determine the differential neutron fluence for these spallation neutrons during a standard IPF production run.

  1. Neutron diagnostics on TFTR utilizing the Campbelling technique

    International Nuclear Information System (INIS)

    The authors report modified commercial neutron counting equipment installed on a tokamak fusion test reactor (TFTR) which utilizes the Campbelling theorem to monitor the neutron source strength at very high neutron count rates. Campbelling utilizes the large amplitude fluctuation from neutron events in the detectors to discriminate against small amplitude noise events. Source strengths yielding equivalent count rates a factor of five higher than possible in the conventional count rate mode have been obtained to date. The concept of Campbelling is discussed and the particular application to TFTR is illustrated

  2. Experience of the Fourier time-of-flight (TOF) neutron techniques for high-resolution neutron diffractometry

    International Nuclear Information System (INIS)

    Fourier TOF techniques for neutron powder diffraction is being developed as a joint Finnish-USSR effort referred to as the Mini-SFINKS project. Presented are the first test results as obtained with the Mini-SFINKS TOF diffractometer put together mainly from the Astacus diffractometer components transported from Otaniemi to Gatchina. Experience gained so far suggests that substantial improvement in neutron economy can be obtained with rather straightforward modifications. (author)

  3. High-sensitivity measurements for low-level TRU wastes using advanced passive neutron techniques

    International Nuclear Information System (INIS)

    In recent years, both passive- and active-neutron nondestructive assay (NDA) systems have been used to measure the uranium and plutonium content in 200-ell drums. Because of the heterogeneity of the wastes, representative sampling is not possible and NDA methods are preferred over destructive analysis. Active-neutron assay systems are used to measure the fissile isotopes such as 235U, 23Pu, and 241Pu; the isotopic ratios are used to infer the total plutonium content and thus the specific disintegration rate. The active systems include 14-MeV-neutron (DT) generators with delayed-neutron counting, (D,T) generators with the differential die-away technique, and 252Cf delayed-neutron shufflers. Passive assay systems (for example, segmented gamma-ray scanners)5 have used gamma-ray sessions, while others (for example, passive drum counters) used passive-neutron signals. We have developed a new passive-neutron measurement technique to improve the accuracy and sensitivity of the NDA of plutonium scrap and waste. This new 200-ell-drum assay system combines the classical NDA method of counting passive-neutron totals and coincidences from plutonium with the new features of ''add-a-source'' (AS) and multiplicity counting to improve the accuracy of matrix corrections and statistical techniques that improve the low-level detectability limits. This paper describes the improvements we have made in passive-neutron assay systems and compares the accuracies and detectability limits of passive- and active-neutron assay systems

  4. Standard Test Method for Determining Thermal Neutron Reaction Rates and Thermal Neutron Fluence Rates by Radioactivation Techniques

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 The purpose of this test method is to define a general procedure for determining an unknown thermal-neutron fluence rate by neutron activation techniques. It is not practicable to describe completely a technique applicable to the large number of experimental situations that require the measurement of a thermal-neutron fluence rate. Therefore, this method is presented so that the user may adapt to his particular situation the fundamental procedures of the following techniques. 1.1.1 Radiometric counting technique using pure cobalt, pure gold, pure indium, cobalt-aluminum, alloy, gold-aluminum alloy, or indium-aluminum alloy. 1.1.2 Standard comparison technique using pure gold, or gold-aluminum alloy, and 1.1.3 Secondary standard comparison techniques using pure indium, indium-aluminum alloy, pure dysprosium, or dysprosium-aluminum alloy. 1.2 The techniques presented are limited to measurements at room temperatures. However, special problems when making thermal-neutron fluence rate measurements in high-...

  5. General Approach To Materials Classification Using Neutron Analysis Techniques

    International Nuclear Information System (INIS)

    The 'neutron in, gamma out' method of elemental analysis has been known and used in many applications as an elemental analysis tool. This method is non-intrusive, non-destructive, fast and precise. This set of advantages makes neutron analysis attractive for even wider variety of uses beyond simple elemental analysis. The question that is addressed within this study is under what conditions neutron analysis can be used to differentiate materials of interest from a group or class of materials in the face of knowing that what is truly of interest is the molecular content of any sample under interrogation. Purpose of the study was to develop a neutron-based scanner for rapid differentiation of classes of materials sealed in small bottles. Developed scanner employs D-T neutron generator as a neutron source and HPGe gamma detectors. Materials can be placed into classes by many different properties. However, neutron analysis method can be used only few of them, such as elemental content, stoichiometric ratios and density of the scanned material. Set of parameters obtainable through neutron analysis serves as a basis for a hyperspace, where each point corresponds to a certain scanned material. Sub-volumes of the hyperspace correspond to different classes of materials. One of the most important properties of the materials are stoichiometric ratios of the elements comprising the materials. Constructing an algorithm for converting the observed gamma ray counts into quantities of the elements in the scanned sample is a crucial part of the analysis. Gamma rays produced in both fast inelastic scatterings and neutron captures are considered. Presence of certain elements in materials, such as hydrogen and chlorine can significantly change neutron dynamics within the sample, and, in turn, characteristic gamma lines development. These effects have been studied and corresponding algorithms have been developed to account for them

  6. Absolute technique for neutron source calibration by radiation induced activity

    International Nuclear Information System (INIS)

    The neutron yield from a Radium Beryllium neutron source has been determined experimentally by the induced Mn-56 activity. The neutron source was placed in the center of a tank filled with aqueous manganese sulphate (MnSO4) solution. Irradiation time usually lasted about 16-18 hours in order to secure saturation. The average induced Mn-56 activity within the MnSO4 bath was then measured by the use of NaI scintillation detector. This detector was placed in a sealed aluminum jacket at the center of the tank. This detector was connected with the necessary electronic counting system and was pre calibrated against a 4 πβ-γ coincidence counting system. The efficiency of the NaI counting system as a function of MnSO4 solution density is investigated as well as the proper dimension of the used tank for the sake of calibration purposes. The neutron leakage within the MnSO4 baths was also investigated for different dimensions of tanks. The experimental errors involved in the counting system were also considered. The numerical value of neutron yield from the used radium beryllium neutron source was given with its corresponding statistical errors as (1.10 + 0.065) x 106 neutron per second

  7. Application of nondestructive gamma-ray and neutron techniques for the safeguarding of irradiated fuel materials

    International Nuclear Information System (INIS)

    Nondestructive gamma-ray and neutron techniques were used to characterize the irradiation exposures of irradiated fuel assemblies. Techniques for the rapid measurement of the axial-activity profiles of fuel assemblies have been developed using ion chambers and Be(γ,n) detectors. Detailed measurements using high-resolution gamma-ray spectrometry and passive neutron techniques were correlated with operator-declared values of cooling times and burnup

  8. Experimental technique of stress analyses by neutron diffraction

    International Nuclear Information System (INIS)

    The structures and main components of neutron diffraction stress analyses spectrometer, SALSA, as well as functions and parameters of each components are presented. The technical characteristic and structure parameters of SALSA are described. Based on these aspects, the choice of gauge volume, method of positioning sample, determination of diffraction plane and measurement of zero stress do are discussed. Combined with the practical experiments, the basic experimental measurement and the related settings are introduced, including the adjustments of components, pattern scattering, data recording and checking etc. The above can be an instruction for stress analyses experiments by neutron diffraction and neutron stress spectrometer construction. (authors)

  9. Biomonitoring plan for Seedskadee National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This proposed biomonitoring plan is for Seedskadee National Wildlife Refuge in Sweetwater county, Wyoming. Biomonitoring is needed for the refuge especially due to...

  10. Experimental Approach for Water Discharge Characteristics at PEMFC by using Neutron Imaging Technique considered Neutron Flux and Linear Attenuation Coefficient of Thermal Neutron Correction at NRF, HANARO

    International Nuclear Information System (INIS)

    The neutron imaging technique was used to investigate the water discharge characteristics at PEMFC. Prior to investigation of water discharge characteristics, the linear attenuation coefficient for water at Neutron Radiography Facility (NRF) was calibrated. The feasibility test apparatus was consisted of pressurized air and water in order to simulate the actual operating PEMFC. The feasibility tests have been performed at 1-parallel serpentine type with 100 cm2 active area and different air flow rate (1, 2, and 4 lpm). The total water volume variations at each condition were calculated from the neutron images. The water at channel is well discharged as soon as supplying the pressurized air into the PEMFC. However, because the water at MEA isn't removed the total water volume is constant after 150. Therefore more effective method is needed in order to discharge water at MEA, and the neutron imaging technique is helpful for it

  11. Validation of the instrumental neutron activation analysis method for mercury analysis in hair samples used for biomonitoring of mercury environmental contamination

    International Nuclear Information System (INIS)

    Environmental mercury contamination has lately become of widespread concern in Brazil owing to gold extraction activities in the Amazon region and also to industrial activities. It is estimated that tonnes of mercury are thrown in the rivers of the Amazon region annually or are evaporated into the open air owing to the amalgamation procedure employed in gold extraction. In the present work, as pail of an IAEA Co-ordinated Research Programme (CRP), three main population groups were studied: a control group of individuals with no suspicion of contamination by mercury; a group of people living near the Billings Dam, located in one of the most heavily industrialized parts of the country, and several Indian tribes living in Xingu Park, an Indian reservation located in the Amazon region. An important part of the CRP was the validation of the analytical methodology for die analysis of total mercury in the hair samples of the population groups studied. Instrumental neutron activation analysis (INAA) was chosen for the analysis of mercury in these samples. It has the advantage of being non-destructive, which can be quite convenient when dealing with a large number of samples, which is the case in epidemiological studies. The experimental procedure consisted of irradiation of the hair samples in the IEA-R1 nuclear research reactor and measurement of the gamma radioactivity of 197Hg. For the validation of the analytical methodology, the following reference materials (RMs) were analysed: IAEA MA-A-2/TM Fish Flesh Homogenate; SHINR GBW-9101 Chinese Human Hair and the candidate RMs IAEA-085 and IAEA-086 Human Hair. The recently acquired RM BCR CRM-397 was also analysed. The accuracy and precision of the INAA method for the analysis of these RMs is discussed, as well as the applicability of the method to the analysis of mercury in the hair of the population groups studied. (author)

  12. Enhanced Performance Neutron Scattering Spectroscopy by Use of Correlation Techniques

    CERN Document Server

    Mezei, F; Migliardo, F; Magazù, S

    2016-01-01

    Neutron correlation spectroscopy can exceed direct spectroscopy in the incoming beam intensity by up to two orders of magnitude at the same energy resolution. However, the propagation of the counting noise in the correlation algorithm of data reduction is disadvantageous for the lowest intensity parts of the observed spectrum. To mitigate this effect at pulsed neutron sources we propose two dimensional time-of-flight recording of each neutron detection event: with respect to both the neutron source pulses and to the rotation phase of the pseudo-random beam modulation statistical chopper. We have identified a formulation of the data reduction algorithm by matching the data processing time channel width to the inherent time resolution of this chopper, which makes the reconstruction of the direct time-of-flight spectra exact and independent of all other contributions to instrumental resolution. Two ways are proposed for most flexible choice of intensity vs. resolution without changing the statistical chopper or ...

  13. Advancement of neutron radiography technique in JRR-3M

    International Nuclear Information System (INIS)

    The JRR-3M thermal neutron radiography facility (JRR-3M TNRF) was completed in the JRR-3M of the Japan Atomic Energy Research Institute in 1991 and has been utilized as research tools for various kinds of research fields such as thermal hydraulic researches, agricultural researches, medical researches, archaeological researches and so on. High performance of the JRR-3M TNRF such as high neutron flux, high collimator ratio and wide radiographing field has enabled advanced researches and stimulated developments of advanced neutron radiography (NR) systems for higher spatial resolution and for higher temporal resolution. Static NR systems using neutron imaging plates or cooled CCD camera with high spatial resolution, a real-time NR system using a silicon intensifier target tube camera and a high-frame-rate NR system using a combination of an image intensifier and a high speed digital video camera with high temporal resolution have been developed to fill the requirements from researchers. (author)

  14. Development of neutron radiography facility for detection of hydrogenous components using recoil protons technique

    International Nuclear Information System (INIS)

    The neutron radiography facility of Egypt second research reactor (ETRR-2)has been developed toward quantitative neutron radiography to detect hydrogenous components in soil and sandstone samples. The development includes using of portable Am241-Be neutron source of activity 1 Ci, rather than using of the reactor neutron radiography beam,i.e., no need for reactor operation .In this paper, the characterization parameters of the neutron source were measured to use the source in measuring of hydrogenous contents in soil using recoil protons technique. The usefulness of this technique is to detect the underground water for ancient Egyptian and islamic heritage protection and use methods to treat soil for preventing water migration inside. Also,sandstone Samples had been studied using the same technique to detect the trace amount of petroleum in domestic sandstone samples from different Egyptian locations.

  15. On the accuracy of techniques for determining neutron compound-nucleus formation cross sections

    Directory of Open Access Journals (Sweden)

    Dietrich F.S.

    2010-03-01

    Full Text Available We consider three methods for determining neutron nonelastic cross sections: direct measurement by transmission of neutrons through a spherical shell; subtraction of the angle-integrated elastic cross section from the total cross section; and a modification of the subtraction technique using Wick’s limit that in favorable cases can significantly reduce the errors in the subtraction method. We show new results using the modified subtraction technique for nonelastic cross sections at 21.6 MeV neutron energy over a wide mass range, and discuss criteria that should be satisfied in order for the modified subtraction technique to be reliable.

  16. Moisture measurements of wood and sugar samples using neutron transmission technique

    International Nuclear Information System (INIS)

    Moisture contents of sugar and shredded wood samples were measured using fast neutron transmission technique. Neutrons with 2.8 MeV energy were produced via D(d,n) reaction. The neutrons transmitted through the wood and sugar samples containing different moisture contents were detected by an NE213 scintillation detector. Monte Carlo simulations were carried out to calculate fast neutron detector counts as a function of water contents (wt%) of wood and sugar samples as well. The experimental results were compared with the results of Monte Carlo simulations. Within the experimental uncertainties, a good agreement has been achieved between the experimental results and the results of the Monte Carlo simulations

  17. Review of measurement techniques for the neutron radiative-capture process

    International Nuclear Information System (INIS)

    The experimental techniques applied in measurements of the neutron capture process are reviewed. The emphasis is on measurement techniques used in neutron capture cross section measurements. The activation technique applied mainly in earlier work has still its use in some cases, specifically for measurements of technologically important cross sections (238U and 232Th) with high accuracy. Three major prompt neutron radioactive capture detection techniques have evolved: the total gamma radiation energy detection technique (mainly with large liquid scintillation detectors), the gamma-energy proportional detectors (with proportional counters or Moxon-Rae detectors), and the pulse-height weighting technique. These measurement techniques are generally applicable, however, shortcomings limit the achievable accuracy to a approx. = 5 to 15% uncertainty level

  18. Neutron irradiation damage analysis of the vessel steel using microscopy and spectroscopy techniques

    International Nuclear Information System (INIS)

    Nuclear reactor vessels are subject to material irradiation induced damage by neutron bombardment from core. Neutrons are classed as fast and thermal, and these produce two different effects. Fast neutrons caused damage by dislocation or displacement of the atomic structure of the metal, whereas the effect of thermal neutrons is one of transmutation of trace impurities that can materially change the properties of reactor vessel structural material. The physical properties of vessel steels are altered by exposure to the high-energy neutrons. Typical changes are a marked increase in yield point, a smaller increase in tensile strength, increase in notch-impact transition temperature and decrease in ductility and fracture energy. The magnitude of these changes is a function of the material, the total absorbed neutron irradiation, and the irradiation temperature. This paper shows some advances of neutron irradiation damage research of the BWR vessels of Laguna Verde Nuclear Centre using non destructive techniques as microscopy electronic, spectroscopy and X-ray diffraction. The transmission electron microscopy and scanning electron microscopy make evident Ni, Cr, Cu, Mo and Mn atoms inside precipitates and around the boundary grain which favour the embrittlement, and other effects, of the vessel steel when their concentrations increase by atom-fast neutron interactions. The aim of this research is to study the microstructure damage of the vessel steel, by neutron irradiation from the core, using non destructive techniques on the design material and the irradiated material of the surveillance capsules that have been extracted of the vessel. (Author)

  19. Development and prospects of Very Small Angle Neutron Scattering (VSANS) techniques

    Science.gov (United States)

    Xuo, Tai-Sen; Cheng, He; Chen, Yuan-Bo; Wang, Fang-Wei

    2016-07-01

    Very Small Angle Neutron Scattering (VSANS) is an upgrade of the traditional Small Angle Neutron Scattering (SANS) technique which can cover three orders of magnitude of length scale from one nanometer to one micrometer. It is a powerful tool for structure calibration in polymer science, biology, material science and condensed matter physics. Since the first VSANS instrument, D11 in Grenoble, was built in 1972, new collimation techniques, focusing optics (multi-beam converging apertures, material or magnetic lenses, and focusing mirrors) and higher resolution detectors combined with the long flight paths and long incident neutron wavelengths have been developed. In this paper, a detailed review is given of the development, principles and application conditions of various VSANS techniques. Then, beam current gain factors are calculated to evaluate those techniques. A VSANS design for the China Spallation Neutron Source (CSNS) is thereby presented. Supported by National Natural Science Foundation of China (21474119, 11305191)

  20. Development and prospect of Very Small Angle Neutron Scattering (VSANS) Techniques

    CERN Document Server

    Zuo, Taisen; Chen, Yuan-Bo; Wang, Fang-Wei

    2016-01-01

    Very Small Angle Neutron Scattering (VSANS) is an upgrade of the traditional Small Angle Neutron Scattering (SANS) technique which can cover three orders of magnitude of length scale from one nanometer to one micrometer. It is a powerful tool for structure calibration in polymer science, biology, material science and condensed matter physics. Since the first VSANS instrument, D11 in Grenoble, was built in 1972, new collimation techniques, focusing optics (multi-beam converging apertures, material or magnetic lenses, and focusing mirrors) and higher resolution detectors combined with the long flight paths and long incident neutron wavelengths have been developed. In this paper, a detailed review is given of the development, principles and application conditions of various VSANS techniques. Then, beam current gain factors are calculated to evaluate those techniques. A VSANS design for the China Spallation Neutron Source (CSNS) is thereby presented.

  1. Development of a dual phantom technique for measuring the fast neutron component of dose in boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Sakurai, Yoshinori, E-mail: yosakura@rri.kyoto-u.ac.jp; Tanaka, Hiroki; Kondo, Natsuko; Kinashi, Yuko; Suzuki, Minoru; Masunaga, Shinichiro; Ono, Koji; Maruhashi, Akira [Kyoto University Research Reactor Institute, Asashironishi 2-1010, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan)

    2015-11-15

    depth dose distributions of the neutron and gamma-ray components along the central axis was performed at Heavy Water Neutron Irradiation Facility installed at Kyoto University Reactor using activation foils and thermoluminescent dosimeters, respectively. Results: Simulation results demonstrated that the absorbing effect for thermal neutrons occurred when the LiOH concentration was over 1%. The most effective Li-6 concentration was determined to be enriched {sup 6}LiOH with a solubility approaching its upper limit. Experiments confirmed that the thermal neutron flux and secondary gamma-ray dose rate decreased substantially; however, the fast neutron flux and primary gamma-ray dose rate were hardly affected in the 10%-{sup 6}LiOH phantom. It was confirmed that the dose contribution of fast neutrons is improved from approximately 10% in the pure water phantom to approximately 50% in the 10%-{sup 6}LiOH phantom. Conclusions: The dual phantom technique using the combination of a pure water phantom and a 10%-{sup 6}LiOH phantom developed in this work provides an effective method for dose estimation of the fast neutron component in BNCT. Improvement in the accuracy achieved with the proposed technique results in improved RBE estimation for biological experiments and clinical practice.

  2. Installation technique of the in-pile plug assembly for the neutron guide system at HANARO

    International Nuclear Information System (INIS)

    The research reactor HANARO in Korea will be equipped with a neutron guide system, in order to transport cold neutrons from the cold neutron source to the neutron scattering instruments in the neutron guide hall near the reactor building. The neutron guide system of HANARO consists of the in-pile plug assembly, the primary shutter, and out-of-pile neutron guides with dedicated secondary shutters. Functions of the in-pile plug assembly are to shield the reactor environment from a nuclear radiation and to support the neutron guides and maintain them precisely oriented. It is most important for the constructing of the neutron guide system to install new in-pile plug assembly with neutron guides precisely at the beam port of the reactor in radiation environment. The installation tool was developed by KAERI, which enables the removal of old in-pile plug and the installation of the new in-pile plug assembly or the guide cassette under radiation shielding. This paper presents the installation technique of the inpile plug assembly using this newly developed tool

  3. Far Subcriticality Measurements by the Pulsed Neutron Technique

    International Nuclear Information System (INIS)

    Subcriticality measurements of the Argonaut reactor were performed with the reactivity as far as -15$. Data are obtained by measuring the time and space distribution of the decaying neutron after the injected burst. The reactor was made subcritical with dummy fuel plates inserted into the system instead of fuel plates. Dummy fuel plates were made with the same absorption cross-section as the fuel. The Kaman Pulsatron was used as the pulsed neutron source. To minimize generation of the higher modes in the initial flux distribution, attention was paid to the positioning of the neutron source. The BF3 counters and the TMC multichannel analyser were used for detection, time analysis and registration. The data were processed using the ZUSE Z-23 digital computer. The results of measurements show the limit of the method. (author)

  4. Neutron-based techniques for detection of explosives and drugs

    International Nuclear Information System (INIS)

    Neutron reflection, scattering and transmission methods combined with the detection of characteristic gamma rays have an increasing role in the identification of hidden explosives, illicit drugs and other contraband materials. There are about 100 million land mines buried in some 70 countries. Among the abandoned anti-personnel land mines (APL) certain types have low mass (about 100 g) and contain little or no metal. Therefore, these plastic APL cannot be detected by the usual metal detectors. The IAEA Physics Section has organized a CRP in 1999 for the development of novel methods in order to speed up the removing process of APL. The transportation of illicit drugs has shown an increasing trend during the last decade. Developments of fast, non-destructive interrogation methods are required for the inspection of cargo containers, trucks and airline baggage. The major constituents of plastic APL and drugs are H, C, N and O which can be identified by the different neutron interactions. The atom fractions of these elements, in particular the C/O, C/N and C/H ratios, are quite different for drugs and explosives as compared to other materials used to hide them. Recently, we have carried out systematic measurements and calculations on the neutron fields from the 9Be(d,n), 2H(d,n), 252Cf and Pu-Be sources passing through different bulky samples, on the possible use of elastically backscattered Pu-Be neutrons in elemental analysis and on the advantages and limitations of the thermal neutron reflection method in the identification of land mines and illicit drugs. The measured spectral shapes of neutrons were compared with the calculated results using the MCNP-4A and MCNP-4B codes. (author)

  5. Internationally harmonised approach to biomonitoring trace element atmospheric deposition

    International Nuclear Information System (INIS)

    The International Atomic Energy Agency (IAEA) has been supporting work on airborne particulate matter since 1992 through various co-ordinated research and technical co-operation projects. In 1997, biomonitoring air pollution using plants, became officially a part of the IAEA project on environmental pollution monitoring and research. Based on: (1) positive experience in using biomonitors, especially lower plants such as mosses and lichens in several developed countries; (2) the continuous use of biomonitors in several Member States; and (3) the fact that nuclear and related analytical techniques have been shown to be particularly appropriate for the analysis of air pollution biomonitors, such studies are now being supported by the IAEA in 14 countries within a co-ordinated research project. The main emphasis of this project is on (1) identification of suitable biomonitors of atmospheric pollution for local and/or regional application, and (2) their validation for general environmental monitoring, whenever possible. Although the participants are using different plants as biomonitors in their research in geographically and climatically diverse parts of the world, they are harmonising sampling approaches and analytical procedures. In this paper, an overview of these activities is given, along with the details, where possible. In all of these activities, proficiency testing and analytical quality assurance are important issue, which merits special attention. To this end, a variety of analytical quality control materials have been used in intercomparison exercises and proficiency testing. Within the scope of the NAT-5 intercomparison exercise, two lichen materials were distributed among 15 participating laboratories and a proficiency test was organised. The results obtained proved satisfactory performance for most participating laboratories. (author)

  6. Neutron Capture Radiography: Neutron Capture Radiography:a technique for isotopic labelling and analytical imaging with a few stable isotopes

    OpenAIRE

    Michel Thellier; Camille Ripoll

    2006-01-01

    NCR (neutron capture radiography) may be used successfully for the imaging of one of the stable isotopes of a few chemical elements (especially 6Li and 10B, possibly also 14N, 17O, and others) and for labelling experiments using these stable isotopes. Other physical techniques compete with NCR. However, NCR can remain extremely useful in a certain number of cases, because it is usually more easily done and is less expensive than the other techniques.

  7. Neutron Capture Radiography: Neutron Capture Radiography:a technique for isotopic labelling and analytical imaging with a few stable isotopes

    Directory of Open Access Journals (Sweden)

    Michel Thellier

    2006-01-01

    Full Text Available NCR (neutron capture radiography may be used successfully for the imaging of one of the stable isotopes of a few chemical elements (especially 6Li and 10B, possibly also 14N, 17O, and others and for labelling experiments using these stable isotopes. Other physical techniques compete with NCR. However, NCR can remain extremely useful in a certain number of cases, because it is usually more easily done and is less expensive than the other techniques.

  8. Determination Of Natural Boron Concentration In Coffee Leaves, Using de Autobiography by Neutron Capture Technique

    International Nuclear Information System (INIS)

    Determination of natural boron concentration in coffee leaves, using the autoradiography, by neutron capture technique. The boron absorption coefficient in young coffee leaves was measured using autoradiography by neutron capture. In two experiments carried out in April and November, 1996, it was found that the coefficient varies between 0.9 and 5.3 nmol/h. the concentration of natural boron in coffee leaves in regard to age, symptoms and treatment received was also studied, using the same technique. (Author)

  9. Neutron activation: an invaluable technique for teaching applied radiation

    International Nuclear Information System (INIS)

    This experiment introduces students to the important method of neutron activation. A sample of aluminium was irradiated with neutrons from an isotropic 241Am-Be source. Using γ-ray spectroscopy, two radionuclide products were identified as 27Mg and 28Al. Applying a cadmium cut-off filter and an optimum irradiation time of 45 min, the half-life of 27Mg was determined as 9.46±0.50 min. The half-life of the 28Al radionuclide was determined as 2.28±0.10 min using a polythene moderator and an optimum irradiation time of 10 min. (author)

  10. Air pollution studies in Tianjing city using neutron activation analysis techniques

    International Nuclear Information System (INIS)

    Two sites of airborne sampling from industrial and residential areas were made in Tianjing city during February and June using PM-10 sampler and analyzed by NAA techniques; Comparison of air pollution between urban and rural area in Tianjing city was made using neutron activation analysis techniques and some other data analyzing techniques. (author)

  11. The role of neutron activation analysis technique Ex Industrial applications using the egyptian research reactor facilities

    International Nuclear Information System (INIS)

    This report covers several papers which deal with the industrial applications of the Neutron Activation Analysis Technique (NAAT) in Egypt. The applications include: exploration, mining, industrial environment and multielemental analysis of different materials, just for quality control, optimization, safety uses and help in improving the efficiency and economic evaluation. The technique principles, instrumentation, neutron irradiation facilities and experience of analysis are reviewed. Also, the current research activities using the ET-RR-1 facilities as well as a proposal for cold neutron applications in this field on the ET-RR-2 are given

  12. Instrumental Neutron Activation Analysis Technique using Subsecond Radionuclides

    DEFF Research Database (Denmark)

    Nielsen, H.K.; Schmidt, J.O.

    1987-01-01

    The fast irradiation facility Mach-1 installed at the Danish DR 3 reactor has been used in boron determinations by means of Instrumental Neutron Activation Analysis using12B with 20-ms half-life. The performance characteristics of the system are presented and boron determinations of NBS standard...

  13. Contribution to the Study of Fast Neutron Non-Multiplying Assemblies by the Pulsed Neutron Technique

    International Nuclear Information System (INIS)

    Pulsed neutrons experiments have been performed on non-multiplying and poorly moderating materials (Fe, Cu, C). The energy of the source neutrons was chosen to be 1400, 1100, 890 and 670 keV. The time variations of the leakage flux have been measured for different locations of the detector. The former was shown to be strongly dependent on the latter. A systematic study of these experiments has been done by the Monte Carlo method using a semi-continuous energy model. The results given by this method are in good agreement with the experimental results and, moreover, the Monte Carlo method is a very useful tool to study the energetic degradation of the primary neutrons. The propagation of the incident neutrons in such assemblies has also been studied by the time-dependent P1 approximation. This method gives analytical results which are also in good agreement with the experimental results. (author)

  14. Development of neutron measurement techniques in reactor diagnostics and determination of water content and water flow

    International Nuclear Information System (INIS)

    The present thesis deals with three comparatively different topics in neutron physics research. These topics are as follows: construction and experimental investigation of a new detector, capable of measuring the neutron current, and investigation of the possibility to use it for the localisation of a neutron source in a simple experimental arrangement; execution of neutron transmission measurements based on a stationary neutron generator, and the study of their suitability for determining the volume porosity of geological samples; study of the possibility for improving the accuracy of water flow measurements based on the pulsed neutron activation technique. The first subject of this thesis concerns the measurement of the neutron current by a newly constructed detector. The motivation for this work stems from a recent suggestion that the performance of core monitoring methods could be enhanced if, in addition to the scalar neutron flux, also the neutron current was measured. To this end, a current detector was based on a scintillator mounted on a fibre and a Cd layer on one side of the detector. The measurements of the 2-D neutron current were performed in an experimental system by using this detector. The efficiency of the detector in reactor diagnostics was illustrated by demonstrating that the position of a neutron source can be determined by measuring the scalar neutron flux and the neutron current in one spatial point. The results of measurement and calculation show both the suitability of the detector construction for the measurement of the neutron current vector and the use of the current in diagnostics and monitoring. The second subject of this thesis concerns fast neutron transmission measurements, based on a stationary neutron generator, for determining the volume porosity of a sample in a model experiment. Such a technique could be used in field measurements with obvious advantages in comparison with thermal neutron transmission techniques, which can

  15. Development of neutron measurement techniques in reactor diagnostics and determination of water content and water flow

    Energy Technology Data Exchange (ETDEWEB)

    Avdic, Senada

    2000-09-01

    The present thesis deals with three comparatively different topics in neutron physics research. These topics are as follows: construction and experimental investigation of a new detector, capable of measuring the neutron current, and investigation of the possibility to use it for the localisation of a neutron source in a simple experimental arrangement; execution of neutron transmission measurements based on a stationary neutron generator, and the study of their suitability for determining the volume porosity of geological samples; study of the possibility for improving the accuracy of water flow measurements based on the pulsed neutron activation technique. The first subject of this thesis concerns the measurement of the neutron current by a newly constructed detector. The motivation for this work stems from a recent suggestion that the performance of core monitoring methods could be enhanced if, in addition to the scalar neutron flux, also the neutron current was measured. To this end, a current detector was based on a scintillator mounted on a fibre and a Cd layer on one side of the detector. The measurements of the 2-D neutron current were performed in an experimental system by using this detector. The efficiency of the detector in reactor diagnostics was illustrated by demonstrating that the position of a neutron source can be determined by measuring the scalar neutron flux and the neutron current in one spatial point. The results of measurement and calculation show both the suitability of the detector construction for the measurement of the neutron current vector and the use of the current in diagnostics and monitoring. The second subject of this thesis concerns fast neutron transmission measurements, based on a stationary neutron generator, for determining the volume porosity of a sample in a model experiment. Such a technique could be used in field measurements with obvious advantages in comparison with thermal neutron transmission techniques, which can

  16. The technique of neutron profile for level determination in a jet oil storage vessel

    International Nuclear Information System (INIS)

    In the present paper, preliminary results related to level determination at a Jet oil storage vessel, located in the International Airport Jose Marti, by the neutron profile technique are brought to discussion. Using an Am-Be (1Ci) neutron source and a thermal He-3 neutron detector, values between 10.8-10.85m in height were encountered during the one wall-side scanning of the vessel. This technique, based on the neutron backscatter principle, was also employed for thickness inspection of wall vessel and as it was expected, lower reinforced steel sheets achieved a slight higher thickness than the upper one. Useful dose rate data are presented in order to show, that this new in our country nondestructive technique can be use in safety conditions for industrial diagnostic assay. (Author)

  17. Feasibility study for the investigation of Nitinol self-expanding stents by neutron techniques

    Energy Technology Data Exchange (ETDEWEB)

    Rogante, M., E-mail: main@roganteengineering.i [Rogante Engineering Office, Contrada San Michele n. 61, 62012 Civitanova Marche (Italy); Pasquini, U. [Image and Neuroradiology Deptms, Azienda USL, Emilia-Romagna Region Health Service, 47023 Cesena (Italy); Rosta, L. [Research Institute for Solid State Physics and Optics, P.O. Box 49, H-1525 Budapest (Hungary); Lebedev, V. [Petersburg Nuclear Physics Institute, Gatchina, St. Petersburg (Russian Federation)

    2011-02-01

    In this paper, neutron techniques - in particular, small angle neutron scattering (SANS) and neutron diffraction (ND) - are considered for the non-destructive characterization of Nitinol artery stents. This roughly equiatomic (50Ni-50Ti at%) shape memory alloy (SMA) exhibits significant properties of superelasticity and biocompatibility that make it suitable to be typically used as smart material for medical implants and devices. Nitinol self-expanding artery stents, as permanent vascular support structures, supply an ideal option to bypass surgery, but they are submitted for the whole of patient's life to the dynamical stress of the artery pulsation and the aggression from the biological environment. These stents, consequently, can suffer from wear and fracture occurrence likely due to a variety of cyclic fatigue, overload conditions and residual stresses. Neutrons have recently become a progressively more important probe for various materials and components and they allow achieving information complementary to those obtained from the traditional microstructural analyses. The outputs from the preliminary works already carried out in this field consent to consider neutron techniques capable to contribute to the development of these crucial medical implants. The achievable results can yield trends adoptable in monitoring of the stent features. -- Research Highlights: {yields} Neutron techniques can contribute to develop Nitinol self-expanding artery stents. {yields} Neutrons investigations can help avoiding wear and fracture events in Nitinol stents. {yields} Neutron techniques can yield trends adoptable in monitoring of Nitinol stent features. {yields} SANS is able to perform a micro- and nano-scale characterization of Nitinol stents. {yields} Neutron Diffraction helps assessing stresses due to the exercise in Nitinol stents.

  18. Nondestructive analysis of the natural uranium mass through the measurement of delayed neutrons using the technique of pulsed neutron source

    International Nuclear Information System (INIS)

    This work presents results of non destructive mass analysis of natural uranium by the pulsed source technique. Fissioning is produced by irradiating the test sample with pulses of 14 MeV neutrons and the uranium mass is calculated on a relative scale from the measured emission of delayed neutrons. Individual measurements were normalised against the integral counts of a scintillation detector measuring the 14 MeV neutron intensity. Delayed neutrons were measured using a specially constructed slab detector operated in anti synchronism with the fast pulsed source. The 14 MeV neutrons were produced via the T(d,n) 4He reaction using a 400 kV Van de Graaff accelerated operated at 200 kV in the pulsed source mode. Three types of sample were analysed, namely: discs of metallic uranium, pellets of sintered uranium oxide and plates of uranium aluminium alloy sandwiched between aluminium. These plates simulated those of Material Testing Reactor fuel elements. Results of measurements were reproducible to within an overall error in the range 1.6 to 3.9%; the specific error depending on the shape, size and mass of the sample. (author)

  19. Technique investigation on large area neutron scintillation detector array

    International Nuclear Information System (INIS)

    The detailed project for developing Large Area Neutron Scintillation Detector Array (LaNSA) to be used for measuring fusion fuel area density on Shenguang III prototype is presented, including experimental principle, detector working principle, electronics system design and the needs for target chamber etc. The detailed parameters for parts are given and the main causes affecting the system function are analyzed. The realization path is introduced. (authors)

  20. PELAN - a transportable, neutron-based UXO identification technique

    International Nuclear Information System (INIS)

    An elemental characterization method is used to differentiate between inert projectiles and UXO's. This method identifies in a non-intrusive, nondestructive manner, the elemental composition of the projectile contents. Most major and minor chemical elements within the interrogated object (hydrogen, carbon, nitrogen, oxygen, fluorine, phosphorus, chlorine, arsenic, etc.) are identified and quantified. The method is based on PELAN - Pulsed Elemental Analysis with Neutrons. PELAN uses pulsed neutrons produced from a compact, sealed tube neutron generator. Using an automatic analysis computer program, the quantities of each major and minor chemical element are determined. A decision-making tree identifies the object by comparing its elemental composition with stored elemental composition libraries of substances that could be contained within the projectile. In a series of blind tests, PELAN was able to identify without failure, the contents of each shell placed in front of it. The PELAN probe does not need to be in contact with the interrogated projectile. If the object is buried, the interrogation can take place in situ provided the probe can be inserted a few centimeters from the object's surface. (author)

  1. Planetary Geochemistry Techniques: Probing In-Situ with Neutron and Gamma Rays (PING) Instrument

    Science.gov (United States)

    Parsons, A.; Bodnarik, J.; Burger, D.; Evans, L.; Floyd, S.; Lin, L.; McClanahan, T.; Nankung, M.; Nowicki, S.; Schweitzer, J.; Starr, R.; Trombka, J.

    2011-01-01

    The Probing In situ with Neutrons and Gamma rays (PING) instrument is a promising planetary science application of the active neutron-gamma ray technology so successfully used in oil field well logging and mineral exploration on Earth. The objective of our technology development program at NASA Goddard Space Flight Center's (NASA/GSFC) Astrochemistry Laboratory is to extend the application of neutron interrogation techniques to landed in situ planetary composition measurements by using a 14 MeV Pulsed Neutron Generator (PNG) combined with neutron and gamma ray detectors, to probe the surface and subsurface of planetary bodies without the need to drill. We are thus working to bring the PING instrument to the point where it can be flown on a variety of surface lander or rover missions to the Moon, Mars, Venus, asteroids, comets and the satellites of the outer planets.

  2. The study of bronze statuettes with the help of neutron-imaging techniques

    OpenAIRE

    Van Langh, R.; Lehmann, E; Hartmann, S.; Kaestner, A.; Scholten, F.

    2009-01-01

    Until recently fabrication techniques of Renaissance bronzes have been studied only with the naked eye, microscopically, videoscopically and with X-radiography. These techniques provide information on production techniques, yet much important detail remains unclear. As part of an interdisciplinary study of Renaissance bronzes undertaken by the Rijksmuseum Amsterdam, neutron-imaging techniques have been applied with the aim of obtaining a better understanding of bronze workmanship during the R...

  3. Determination of U-235 quantity in fresh fuel elements by neutron coincidence collar technique

    International Nuclear Information System (INIS)

    The U-235 quantity per lenght of fresh fuel assemblies of the Angra-I first recharge was determined by Neutron Coincidence Collar technique (N.C.C.). This technique is well-founded in fresh fuel assemblies activation by thermal neutrons from AmLi source to generate U-235 fission neutrons. These neutrons are detected by coincidence method in polyethylene structure where 18 He-3 detectors were placed. The coincidence counting results, in active mode (AmLi), showed 0,7% to standard deviation and equal to 1,49% to mass in 1000s of counting. The accuracies of different calibration methods were evaluated and compared. The results showed that the operator declared values are consistent. This evaluation was part of technical-exchange program between Safeguards Laboratory from C.N.E.N. and Los Alamos National Lab., United States. (author)

  4. Implementation of the neutron noise technique under the UBERA-6 project

    International Nuclear Information System (INIS)

    Using the neutron noise technique, kinetics parameters estimations and power calibration were performed in the new core of the RA-6 reactor. These activities were carried on under the nuclear start-up of the UBERA-6 project, which consist in the change of core and power increase of the reactor. In a first stage, in joint with the power estimation, the decay constant of the prompt neutrons (αc) was estimated. Its value was found to agree with the calculations obtained from neutron codes. Lately, in the high power stage, estimators of the calibration factors for the 16N detection device were obtained. A thorough analysis of the linearity of the instrumentation used was done, and an alternative methodology was applied in order to estimate the aforementioned factor. The calibration factor obtained by the neutron noise technique was in agreement with the one obtained by thermal balance. (author)

  5. Anti-Personnel Mine Detection by Neutron Backscattering Technique Using MCNP Simulation

    International Nuclear Information System (INIS)

    The neutron backscattering technique NBS has been applied for land mine detection if the soil is sufficiently dry. The detection of anti - personnel (AP) land mine by neutron backscattering technique has been studied by using Monte Carlo N - Particle (MCNP4B) code. The effect of the burial depth and side position of anti-personnel land mine has been discussed. A two dimensional position sensitive detector is simulated by MCNP4B to obtain an image of the back scattered slow neutrons radiation. Results of simulation using mono- energetic point neutron source (2.45 MeV) are presented. The on-mine to no - mine signal ratio images are presented for different positions and depths

  6. Two non-destructive neutron inspection techniques: prompt gamma-ray activation analysis and cold neutron tomography

    OpenAIRE

    Baechler, Sébastien; Dousse, Jean-Claude; Jolie, Jan

    2005-01-01

    Deux techniques d’inspection non-destructives utilisant des faisceaux de neutrons froids ont été développées à la source de neutrons SINQ de l’Institut Paul Scherrer : (1) l’analyse par activation neutronique prompte (PGAA) et (2) la tomographie neutronique. L’analyse par PGA (Prompt Gamma-ray Activation) est une méthode nucléaire qui permet de déterminer la concentration d’éléments présents dans un échantillon. Cette technique consiste à détecter les rayons gamma prompts émis par l’échantill...

  7. Neutronic calculations for CANDU thorium systems using Monte Carlo techniques

    Science.gov (United States)

    Saldideh, M.; Shayesteh, M.; Eshghi, M.

    2014-08-01

    In this paper, we have investigated the prospects of exploiting the rich world thorium reserves using Canada Deuterium Uranium (CANDU) reactors. The analysis is performed using the Monte Carlo MCNP code in order to understand how much time the reactor is in criticality conduction. Four different fuel compositions have been selected for analysis. We have obtained the infinite multiplication factor, k∞, under full power operation of the reactor over 8 years. The neutronic flux distribution in the full core reactor has already been investigated.

  8. Non-destructive-Testing of Nuclear Fuel Element by Means of Neutron Imaging Technique

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Nuclear fuel element is the key component of nuclear reactor. People have to make strictly testing of the element to make sure the reactor operating safely. Neutron imaging is one of Non-destructive-Testing (NDT) techniques, which are very important techniques for

  9. New techniques in neutron data measurements above 30 MeV

    International Nuclear Information System (INIS)

    Recent developments in experimental facilities have enabled new techniques for measurements of neutron interactions above 30 MeV. Foremost is the development of both monoenergetic and continuous neutron sources using accelerators in the medium energy region between 100 and 800 MeV. Measurements of the reaction products have been advanced by the continuous improvement in detector systems, electronics and computers. Corresponding developments in particle transport codes and in the theory of nuclear reactions at these energies have allowed more precise design of neutron sources, experimental shielding and detector response. As a result of these improvements, many new measurements are possible and the data base in this energy range is expanding quickly

  10. JAEA − JRC collaboration on the development of active neutron NDA techniques

    OpenAIRE

    KURETA M.; Koizumi, M.; OHZU A.; Furutaka, K.; Tsuchiya, H.; SEYA M.; Harada, H.; ABOUSAHL Said; HEYSE JAN; Kopecky, Stefan; MONDELAERS Willy; PEDERSEN Bent; SCHILLEBEECKX Peter

    2015-01-01

    The Japan Atomic Energy Agency in collaboration with the Joint Research Centre of the European Commission started a program titled “Development of active neutron NDA techniques”. The program aims at developing an innovative non-destructive analysis (NDA) system for various applications in the field of nuclear safety, security and safeguards. A Non Destructive Analysis (NDA) system is proposed that is based on a combination of different active neutron interrogation techniques, i.e. DDA (Di...

  11. Development Of A Digital Technique For The Determination Of Fission Fragments And Emitted Prompt Neutron Characteristics

    Science.gov (United States)

    Varapai, N.; Hambsch, F.-J.; Oberstedt, S.; Serot, O.; Barreau, G.; Kornilov, N.; Zeinalov, Sh.

    2005-11-01

    The present work demonstrates the application of the digital technique for nuclear measurements. This method has been implemented for measurements of promptly emitted fission neutrons in coincidence with fission fragments from 252Cf(sf). A double Frisch-grid ionization chamber is used as fission fragment detector. The promptly emitted neutrons are detected by a NE213 liquid scintillation detector. The experimental set-up is installed at the Institute for Reference Materials and Measurements. Preliminary results are presented.

  12. Radio-analysis of hydrogenous material using neutron back-scattering technique

    International Nuclear Information System (INIS)

    In this work, we have explored the possibility of using neutron back-scattering technique in performing radio analysis for samples of hydrogenous materials such as explosives, drugs, crude oil and water, looking for different signals that may be used to discriminate these samples. Monte Carlo simulations were carried out to model the detection system and select the optimal geometry as well. The results were determined in terms of the energy spectra of the back-scattered neutrons.(Author)

  13. An Analysis Technique for Active Neutron Multiplicity Measurements Based on First Principles

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Louise G [Los Alamos National Laboratory; Goddard, Braden [Los Alamos National Laboratory; Charlton, William S [Los Alamos National Laboratory; Peerani, Paolo [European Commission, EC-JRC-IPSC

    2012-08-13

    Passive neutron multiplicity counting is commonly used to quantify the total mass of plutonium in a sample, without prior knowledge of the sample geometry. However, passive neutron counting is less applicable to uranium measurements due to the low spontaneous fission rates of uranium. Active neutron multiplicity measurements are therefore used to determine the {sup 235}U mass in a sample. Unfortunately, there are still additional challenges to overcome for uranium measurements, such as the coupling of the active source and the uranium sample. Techniques, such as the coupling method, have been developed to help reduce the dependence of calibration curves for active measurements on uranium samples; although, they still require similar geometry known standards. An advanced active neutron multiplicity measurement method is being developed by Texas A&M University, in collaboration with Los Alamos National Laboratory (LANL) in an attempt to overcome the calibration curve requirements. This method can be used to quantify the {sup 235}U mass in a sample containing uranium without using calibration curves. Furthermore, this method is based on existing detectors and nondestructive assay (NDA) systems, such as the LANL Epithermal Neutron Multiplicity Counter (ENMC). This method uses an inexpensive boron carbide liner to shield the uranium sample from thermal and epithermal neutrons while allowing fast neutrons to reach the sample. Due to the relatively low and constant fission and absorption energy dependent cross-sections at high neutron energies for uranium isotopes, fast neutrons can penetrate the sample without significant attenuation. Fast neutron interrogation therefore creates a homogeneous fission rate in the sample, allowing for first principle methods to be used to determine the {sup 235}U mass in the sample. This paper discusses the measurement method concept and development, including measurements and simulations performed to date, as well as the potential

  14. The Pulsed Neutron Technique Applied to Fast Non-Multiplying Assemblies

    International Nuclear Information System (INIS)

    A nanosecond pulsed Van de Graaff accelerator has been used to study the behaviour of fast neutrons in non-multiplying metal assemblies. A pulsed neutron source technique has been utilized to measure fast non-elastic cross-sections for iron. The method employed is similar to that used to measure absorption cross-sections in thermal assemblies, with the exception that the fast decay times are of the order of nanoseconds rather than microseconds. Nanosecond bursts of monoenergetic neutrons are injected into various size iron assemblies. The neutron flux in these assemblies is observed to decay exponentially with a characteristic decay constant. The decay constant is composed of a sum of terms which represent neutron loss due to leakage and energy degradation. Energy degradation represents a neutron loss since a biased neutron detector is used. The removal term due to elastic and nonelastic scattering can be determined by measuring the decay constant as a function of assembly size. A theoretical development is presented for calculating the fraction that the elastic scattering contributes to the removal term, hence the non-elastic cross-section can be determined. The theoretical treatment for calculating the elastic contribution has been verified experimentally. The non-elastic cross-section for iron has been measured by this technique for primary neutron energies between 0.8 and 1.5 MeV. The pulsed source technique described above has been used to measure decay constants for lead slabs. The experiment approximates the assumptions which are generally made when solving the time-dependent Boltzmann transport equation (i.e. one-dimension, one-velocity). Decay constants have been measured for 28 in x 32 in lead slabs of 2, 4, 6 and 8-in thickness. The results, after being corrected for energy degradation and finite assembly, are compared with the approximate solutions of the Boltzmann transport equation. (author)

  15. Crosscorrelation techniques in neutron polarisation analysis time-of-flight studies

    International Nuclear Information System (INIS)

    A method of performing time-of-flight measurements on a neutron polarisation analysis instrument is described. The method involves a crosscorrelation technique in which the neutron beam polarisation prior to the scattering sample is modulated by a neutron spin flipper according to a predetermined pseudo random sequence. It is shown that the final crosscorrelation of the measured count rate at the detector with the pseudo random sequence yields a time-of-flight spectrum which is proportional to the difference between the spin flip and non spin flip scattering cross-sections of the sample. Implementation of the technique and an example of its use are discussed. It is also shown that in a simple form the crosscorrelation technique is useful in providing discrimination against inelastic scattering. (author)

  16. Efficient fission neutron spectrum matrix representation by singular value decomposition technique

    International Nuclear Information System (INIS)

    In order to treat efficiently a huge fission neutron spectrum (FNS) matrix in a criticality calculation, the singular value decomposition (SVD) technique is introduced to an FNS matrix representation. The required number of SVD components for reconstruction of an FNS matrix is expected to be small since an incident neutron energy dependence of FNS is not so significant. The proposed technique of an SVD-based representation for a fission source term is tested in several fast critical systems. Through an observation of critical eigenvalue dependence on the number of considered SVD components, only six or seven components are required to obtain a critical eigenvalue which agrees with the reference solution within 10-4 dk/kk'. It is also confirmed that a small reactivity effect caused by neutron spectrum shifting can be accurately calculated with the proposed technique. (author)

  17. Neutron/gamma dose separation by the multiple-ion-chamber technique

    International Nuclear Information System (INIS)

    Many mixed n/γ dosimetry systems rely on two dosimeters, one composed of a tissue-equivalent material and the other made from a non-hydrogenous material. The paired chamber technique works well in fields of neutron radiation nearly identical in spectral composition to that in which the dosimeters were calibrated. However, this technique is drastically compromised in phantom due to the degradation of the neutron spectrum. The three-dosimeter technique allows for the fall-off in neutron sensitivity of the two non-hydrogenous dosimeters. Precise and physically meaningful results were obtained with this technique with a D-T source in air and in phantom and with simultaneous D-T neutron and 60Co gamma ray irradiation in air. The MORSE-CG coupled n/γ three-dimensional Monte Carlo code was employed to calculate neutron and gamma doses in a water phantom. Gamma doses calculated in phantom with this code were generally lower than corresponding ion chamber measurements. This can be explained by the departure of irradiation conditions from ideal narrow-beam geometry. 97 references

  18. The soil moisture and its effect on the detection of buried hydrogenous material by neutron backscattering technique

    Energy Technology Data Exchange (ETDEWEB)

    Rezaei Ochbelagh, D. [Department of Physics, University of Mohaghegh Ardabili, P.O. Box 179, Ardabil (Iran, Islamic Republic of)], E-mail: ddrezaey@yahoo.com; Miri Hakimabad, H.; Izadi Najafabadi, R. [Physics Department, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of)

    2009-05-15

    Among the available nuclear techniques, the neutron backscattering technique, based on the detection of the produced thermal neutrons, is thought to be the most promising for landmine detections. The results obtained from Monte Carlo simulation were used for selection of BF{sub 3} detector and Am-Be neutron source shielding. In addition, soil moisture was discussed as a limitation of the neutron backscattering technique. It was experimentally found that this technique is useful for soil whose water content is lower than 14%.

  19. Studies on new neutron-sensitive dosimeters using an optically stimulated luminescence technique

    Science.gov (United States)

    Kulkarni, M. S.; Luszik-Bhadra, M.; Behrens, R.; Muthe, K. P.; Rawat, N. S.; Gupta, S. K.; Sharma, D. N.

    2011-07-01

    The neutron response of detectors prepared using α-Al 2O 3:C phosphor developed using a melt processing technique and mixed with neutron converters was studied in monoenergetic neutron fields. The detector pellets were arranged in two different pairs: α-Al 2O 3:C + 6LiF/α-Al 2O 3:C + 7LiF and α-Al 2O 3:C + high-density polyethylene/α-Al 2O 3:C + Teflon, for neutron dosimetry using albedo and recoil proton techniques. The optically stimulated luminescence response of the Al 2O 3:C + 6,7LiF dosimeter to radiation from a 252Cf source was 0.21, in terms of personal dose equivalent Hp(10) and relative to radiation from a 137Cs source. This was comparable to results obtained with similar detectors prepared using commercially available α-Al 2O 3:C phosphor. The Hp(10) response of the α-Al 2O 3:C + 6,7LiF dosimeters was found to decrease by more than two orders of magnitude with increasing neutron energy, as expected for albedo dosimeters. The response of the α-Al 2O 3:C + high-density polyethylene/α-Al 2O 3:C + Teflon dosimeters was small, of the order of 1% to 2% in terms of Hp(10) and relative to radiation from a 137Cs source, for neutron energies greater than 1 MeV.

  20. A Novel Scanning Land Mine Detector Based on the Technique of Neutron Back Scattering Imaging

    OpenAIRE

    Bom, V.; A.M. Osman; Monem, A.M.A.

    2008-01-01

    The neutron back-scattering (NBS) technique is a well established method to find hydrogen in objects. It can be applied in land mine detection taking advantage of the fact that land mines are abundant in hydrogen. The NBS technique is suitable for land mine scanning e.g., seeking for land mines with a moving detector system, because of the high speed of operation. Scan speeds up to 800 mm/s are reported here depending on the intensity of the neutron source, the mine size and the depth at whic...

  1. Detection of drugs and explosives using neutron computerized tomography and artificial intelligence techniques

    International Nuclear Information System (INIS)

    In this study the development of a methodology to detect illicit drugs and plastic explosives is described with the objective of being applied in the realm of public security. For this end, non-destructive assay with neutrons was used and the technique applied was the real time neutron radiography together with computerized tomography. The system is endowed with automatic responses based upon the application of an artificial intelligence technique. In previous tests using real samples, the system proved capable of identifying 97% of the inspected materials.

  2. Measurement of inner residual stress of bearing by neutron diffraction technique

    International Nuclear Information System (INIS)

    Neutron diffraction technique is one of prevailing method to measure inner structure of material, such as molecular arrangement and lattice spacing by means of penetration of neutron. In particular the residual stress measurement by neutron diffraction has been developed and is greatly performed in many research facilities, because the examination of residual stress existing materials is critically important to estimate fatigue of the materials and to maintain structural objects for efficient utilization. We performed a measurement of residual stress of bearings used for rotating equipment at power plant in the JRR-3 (JAEA) after performing loading rotation test on the bearings. The measuring machine is called RESA(Neutron Diffractometer for Residual Stress Analysis). We used two samples, one was new and the other was fatigued by the test above. The result indicates us that the inner residual stress distribution clearly changed. We summarize this difference and consider several possible causes below. (author)

  3. Harmonised human biomonitoring in Europe

    DEFF Research Database (Denmark)

    Joas, Reinhard; Casteleyn, Ludwine; Biot, Pierre;

    2012-01-01

    Human biomonitoring (HBM) can be an effective tool to assess human exposure to environmental pollutants and potential health effects and is increasingly seen as an essential element in a strategy when integrating health and environment. HBM can be used (i) to prioritise actions and measures for...... policy making; (ii) to evaluate policy actions aimed at reducing exposure to potentially hazardous environmental stressors; and (iii) to promote more comprehensive health impact assessments of policy options. In support of the European Environment and Health Action Plan 2004-2010, European scientists......, experts from authorities and other stakeholders joined forces to work towards developing a functional framework and standards for a coherent HBM in Europe. Within the European coordination action on human biomonitoring, 35 partners from 27 European countries in the COPHES consortium aggregated their...

  4. Assessment of Spatial Variability of Heavy Metals in Metropolitan Zone of Toluca Valley, Mexico, Using the Biomonitoring Technique in Mosses and TXRF Analysis

    OpenAIRE

    Graciela Zarazúa-Ortega; Josefina Poblano-Bata; Samuel Tejeda-Vega; Pedro Ávila-Pérez; Carmen Zepeda-Gómez; Huemantzin Ortiz-Oliveros; Guadalupe Macedo-Miranda

    2013-01-01

    This study is aimed at assessing atmospheric deposition of heavy metals using the epiphytic moss genera Fabronia ciliaris collected from six urban sites in the Metropolitan Zone of the Toluca Valley in Mexico. The concentrations of K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Sr, and Pb were determined by total reflection X-ray fluorescence technique. Results show that the average metal concentration decrease in the following order: Fe (8207 mg/Kg) > Ca (7315 mg/Kg) > K (3842 mg/Kg) > Ti (387 mg...

  5. Measurement of U-235 Fission Neutron Spectra Using a Multiple Gamma Coincidence Technique

    Science.gov (United States)

    Ji, Chuncheng; Kegel, G. H. R.; Egan, J. J.; DeSimone, D. J.; Alimeti, A.; Roldan, C. F.; McKittrick, T. M.; Kim, D.-S.; Chen, X.; Tremblay, S. E.

    2005-05-01

    The Los Alamos Model of Madland and Nix predicts the shape of the fission neutron energy spectrum for incident primary neutrons of different energies. Verifications of the model normally are limited to measurements of the fission neutron spectra for energies higher than that of the primary neutrons because the low-energy spectrum is distorted by the admixture of elastically and inelastically scattered neutrons. This situation can be remedied by using a measuring technique that separates fission from scattering events. One solution consists of using a fissile sample so thin that fission fragments can be observed indicating the occurrence of a fission event. A different approach is considered in this paper. It has been established that a fission event is accompanied by the emission of between seven and eight gamma rays, while in a scattering interaction, between zero and two gammas are emitted, so that a gamma multiplicity detector should supply a datum to distinguish a fission event from a scattering event. We proceed as follows: A subnanosecond pulsed and bunched proton beam from the UML Van de Graaff generates nearly mono-energetic neutrons by irradiating a thin metallic lithium target. The neutrons irradiate a 235U sample. Emerging neutron energies are measured with a time-of-flight spectrometer. A set of four BaF2 detectors is located close to the 235U sample. These detectors together with their electronic components identify five different events for each neutron detected, i.e., whether four, three, two, one, or none of the BaF2 detectors received one (or more) gamma rays. We present work, preliminary to the final measurements, involving feasibility considerations based on gamma-ray coincidence measurements with four BaF2 detectors, and the design of a Fission-Scattering Discriminator under construction.

  6. Biomonitoring for the photovoltaics industry

    Energy Technology Data Exchange (ETDEWEB)

    Bernholc, N.M.; Moskowitz, P.D.

    1995-07-01

    Biomonitoring often is used as a method for estimating the dose to an individual. Therefore, a parameter of measurement, or biomarkers must be identified. The purpose of this paper is to give an overview of biomonitoring protocols for metals used in the photovoltaics industry. Special attention is given to areas that often are skimmed over, to gain insights into some of the problems that may arise when these tasks are carried out. Biological monitoring can be used to determine current human exposures to chemicals, as well as to detect past exposures, and the effects that these exposures may have on human health. It is used in conjunction with environmental monitoring to describe more completely worker`s exposures to, and absorption of, chemicals in the workplace. Biological specimens (e.g., blood, hair or urine) are analyzed for chemical agents, metabolites, or for some specific effect on the person (Lowry 1994). Biomonitoring can assess a workers exposure to industrial chemicals by all routes including skin absorption and ingestion. Although the methodology still is in its infancy, in cases where the procedures have been developed, it can be an invaluable component of an ongoing program of industrial hygiene monitoring. Like any technology, there are limitations to its effectiveness because of a lack of knowledge, contamination of specimens, and the introduction of errors.

  7. Assessment of Spatial Variability of Heavy Metals in Metropolitan Zone of Toluca Valley, Mexico, Using the Biomonitoring Technique in Mosses and TXRF Analysis

    Directory of Open Access Journals (Sweden)

    Graciela Zarazúa-Ortega

    2013-01-01

    Full Text Available This study is aimed at assessing atmospheric deposition of heavy metals using the epiphytic moss genera Fabronia ciliaris collected from six urban sites in the Metropolitan Zone of the Toluca Valley in Mexico. The concentrations of K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Sr, and Pb were determined by total reflection X-ray fluorescence technique. Results show that the average metal concentration decrease in the following order: Fe (8207 mg/Kg > Ca (7315 mg/Kg > K (3842 mg/Kg > Ti (387 mg/Kg > Mn, Zn (191 mg/Kg > Sr (71 mg/Kg > Pb (59 mg/Kg > Cu, V (32 mg/Kg > Cr (24 mg/Kg > Rb (13 mg/Kg > Ni (10 mg/Kg. Enrichment factors show a high enrichment for Cr, Cu, Zn, and Pb which provides an evidence of anthropogenic impact in the industrial and urban areas, mainly due to the intense vehicular traffic and the fossil fuel combustion. Monitoring techniques in mosses have proved to be a powerful tool for determining the deposition of heavy metals coming from diverse point sources of pollution.

  8. Calculation of the reactor neutron time of flight spectrum by convolution technique

    International Nuclear Information System (INIS)

    It is a very complex and time-consuming process to simulate the nuclear reactor neutron spectrum from the reactor core to the export channel by applying a Monte Carlo program. This paper presents a new method to calculate the neutron spectrum by using the convolution technique which considers the channel transportation as a linear system and the transportation scattering as the response function. It also applies Monte Carlo Neutron and Photon Transport Code (MCNP) to simulate the response function numerically. With the application of convolution technique to calculate the spectrum distribution from the core to the channel, the process is then much more convenient only with the simple numerical integral numeration. This saves computer time and reduces some trouble in re-writing of the MCNP program. (general)

  9. Calculation of the reactor neutron time of flight spectrum by convolution technique

    Institute of Scientific and Technical Information of China (English)

    Cheng Jin-Xing; Ouyang Xiao-Ping; Zheng Yi; Zhang An-Hui; Ouyang Mao-Jie

    2008-01-01

    It is a very complex and tlme-consuming process to simulate the nuclear reactor neutron spectrum from the reactor core to the export channel by applying a Monte Carlo program. This paper presents a new method to calculate the neutron spectrum by using the convolution technique which considers the channel transportation as a linear system and the transportation scattering as the response function. It also applies Monte Carlo Neutron and Photon Transport Code (MCNP) to simulate the response function numerically. With the application of convolution technique to calculate thespectrum distribution from the core to the channel, the process is then much more convenient only with the simple numerical integral numeration. This saves computer time and reduces some trouble in re-writing of the MCNP program.

  10. Use of data assimilation techniques in neutronics: benefits and first results

    International Nuclear Information System (INIS)

    Data assimilation (DA) is a set of stochastic inverse optimization techniques using all available measures of the state of a system, weighted by their precision, and computer code modeling the system behavior to estimate the system state vector or parameters in some optimal way (by maximizing the likelihood or minimizing the variance). In this paper, DA techniques which have proven to be efficient in the fields of meteorological forecast and oceanography, are applied to neutronics. Two applications are presented, where such techniques can be used to enhance optimization: 3-dimensional neutronic field interpolation in on line core monitoring and parameter estimation in code qualification procedures. First, main bases of data assimilation theory are shortly presented. Calibration and estimation procedures which are in use today at EDF are then briefly introduced. We also analyze their main limitations and the potential improvements that the use of various DA techniques can provide. We present the MANARA mock-up, which computes a 3-dimensional field interpolation and has been implemented in a DA-dedicated coupling platform, called PALM. Result validation and comparison with former interpolation procedure are also presented. At last, the principles of the KAFEINE mock-up, which implements an extended Kalman filter are displayed. This application covers the field of optimal parameter calibration using the in-core measures. As a conclusion, these first two applications to neutronics, seem very promising, especially in the perspective of the new generation of neutronic solvers which are being developed in the frame of the DESCARTES project

  11. Hidden substances identification by detection of fast neutron induced γ rays using associated α particle technique

    International Nuclear Information System (INIS)

    Measurements have been made of characteristic gamma rays spectra from A(n,n'γ)A reactions induced by 14.1 MeV neutrons on bulk samples of different substances: C, H2O, SiO2, C3H6N6 and samples of soil. Background radiation was reduced by the associated alpha particle technique

  12. New pre-soaking technique for PADC and application to wide-range personal neutron dosimeter

    International Nuclear Information System (INIS)

    Poly allyl diglycol carbonate (PADC) plastic has been widely used as one of most sensitive detectors for personal neutron dosimeter. However, a considerably large number of false pits, which are very difficult to be distinguished from etched tracks induced by neutrons, appear even on the surface of non-irradiated PADC plastic. We have developed a new pre-soaking technique where PADC is soaked in a chemical solution before etching process. Owing to this procedure, the number of false background pits could be successfully reduced by one tenth compared with that for non-treated PADC samples. We have also applied this improved type of PADC practically to personal neutron dosimetry, coupled with a polyethylene sheet for fast neutrons in MeV region and a boron nitride sheet for lower energy neutrons. The measured detection efficiency of the dosimeter mounted on the water phantom was compared with results calculated by Monte Carlo simulation using the MCNP4C2 code. It was confirmed that the energy response of the dosimeter evaluated by the sum of etch-pits on two regions would agree well with the energy dependence of the neutron-fluence to personal-dose-equivalent conversion coefficient given by ICRP Publication 74

  13. Pinus roxburghii plant needles as a three-season biomonitor for elemental air pollution monitoring along roadside

    International Nuclear Information System (INIS)

    The present study deals with the determination of 36 elements in Pinus roxburghii plant needles to assess their potential as biomonitor for elemental air pollution monitoring. The elemental quantification was made by employing Instrumental Neutron Activation Analysis (INAA) and Atomic Absorption Spectrometric (AAS) techniques. The needles of Pinus roxburghii were collected in spring, summer and winter seasons from various sites in Islamabad. The method validation was performed by analyzing two certified reference materials i.e., Citrus leaves - NIST-SRM-1572 and IAEA-Soil-7. Pollution level was assessed by using three indicators: enrichment factor, pollution load index and average toxic element concentration. The results indicated that the needles of Pinus roxburghii plant had potential to monitor the extent of air pollution in the vicinity of high traffic areas.

  14. Vectorization techniques for neutron transport Monte Carlo codes

    International Nuclear Information System (INIS)

    Four Monte Carlo codes, KENO IV, MORSE-DD, MCNP and VIM, have been vectorized already at JAERI Computing Center aiming at an increase in clculation performance, and speed-up ratios of vectorized codes to the original ones were found to be low values between 1.3 and 1.5. In this report the vectorization processes for these four codes are reviewed comprehensively, and methods of analysis for vectorization, modification of control structures of codes and debugging techniques are discussed. The reason for low speed-up ratios is also discussed. (author)

  15. Solar powered irrigation management using neutron scattering technique

    International Nuclear Information System (INIS)

    designed (metal frame, detecting sensors and DC motor with gear-box) and used for this purpose. 28% more power output was gained.3.Matching system components with DC motor obtained from local markets to meet PV generator performance. Performance curves of both PV generator and DC motor was plotted.4.Setting up a pumping system matches the PV output, pump efficiency was calculated (30%) at 1100 rpm.5.Hourly pump discharge and reference evapotranspiration (ETo) were estimated using 10 years meteorological data averages (Meteo-Norm Software), years (1995-2005). Analysis showed that the strongest correlation was between the solar radiation and ETo, while solar radiation with other parameters affecting ETo such as temperature, RH% were not that strong. Correlations between both hourly solar radiation and air temperature were positive and highly significant. Calculations were made to determine area to be cultivated using the pumping system under study, to meet ETo. Results ranged from more than 4 feddan at winter time to 2.3 feddan in summer season. 6. Determination of actual evapotranspiration (ETo) using neutron moisture meter for the evaluation of estimated (ETo). Actual evapotranspiration (ETa) values were calculated within the wet area around emitter (location of plant) in five sites (S1, S2, S3, S4 and S5). Average ETa values for three replicates for the five sites in developing stage of squash plant were calculated.

  16. Communication in a Human biomonitoring study

    DEFF Research Database (Denmark)

    Exley, Karen; Cano, Noemi; Aerts, Dominique;

    2015-01-01

    A communication strategy was developed by The Consortium to Perform Human Biomonitoring on a European Scale (COPHES), as part of its objectives to develop a framework and protocols to enable the collection of comparable human biomonitoring data throughout Europe. The framework and protocols were...... tested in the pilot study DEMOCOPHES (Demonstration of a study to Coordinate and Perform Human biomonitoring on a European Scale). The aims of the communication strategy were to raise awareness of human biomonitoring, encourage participation in the study and to communicate the study results...... and stakeholders, followed by dissemination at European level. Several lessons were learnt that may assist other future human biomonitoring studies. Recruitment took longer than anticipated and so social scientists, to help with community engagement, should be part of the research team from the start...

  17. Lichens as biomonitors with special reference to Antarctica

    International Nuclear Information System (INIS)

    Lichens are effective biomonitors of metal deposition. Lichens are slow growing and assimilate metals at a rapid rate but release them at a low rate. Metal concentrations in lichen thalli have been shown to correlate with atmospheric levels. Lichens have been first used as bioaccumulative indicators in relation to point emission sources. Lichens have also been used to assess deposition patterns and heavy metal burdens for larger scale monitoring purposes. There are two problems to be kept in mind if lichens are to be effectively used as biomonitors. The first one is concerned with the chemical analyses. Results are more useful when background elemental levels are obtained. The choice of analytical method will depend on the purpose of the respective survey. Instrumental neutron activation analysis (INAA), atomic absorption spectrometry (AAS), Inductively coupled plasma emission spectrometry (ICP-ES) and epithermal neutron activation analysis (ENAA) are among the most commonly used methods. The second problem arises from the variability of lichens. Sources of variability include intra-individual variation, intra-species variation and variation due to microhabitat, locality or edaphic factors. Apart from individual variation, many of these sources of variation can be overcome by careful and thoughtful sampling and analysis of the selected species. Lichens and mosses are the only vegetation in Antarctica. The absence of air pollution in Antarctica suggests that lichens can be used as biomonitors of pollution at small scales around research bases. However, the unpolluted Antarctic environment presents opportunity for baseline studies on heavy metal bioaccumulation. Bioaccumulation in Antarctic lichens can allow a larger (global) scale insight into the airborne heavy metal circulation and deposition. Both high precision analytical methods and biological studies will be needed. (author)

  18. A neutron activation technique for the analysis of cryolite in core samples

    International Nuclear Information System (INIS)

    A short-lived, delayed neutron activation technique has been investigated to determine the content of cryolite (Na3AlF6) in core samples by the detection of fluorine through the fast neutron reaction 19F(n,α)16N. The resultant γ-rays in the energy range of 2.84-8.14 MeV, measured for pure cryolite and background samples, established that cryolite concentrations > 13.6 wt% in rock samples could be estimated with uncertainties of about ± 4.3 wt%. The results are very satisfactory for exploration purposes. (author)

  19. Twenty Five Years of Neutron Activation Analysis: A Personal Perspective on Utilization of the Techniques

    International Nuclear Information System (INIS)

    Since the late 1970's there have been enormous changes in the methods, techniques and applications of neutron activation analysis. Having been a research scientist at the National Research Council of Canada and the McMaster Nuclear Reactor, as well as a professor for ten years at the University of Illinois and 15 years at the University of Texas, I have a unique perspective on the research performed by my many MS, PhD and even undergraduate students. Below is a personal perspective on the utilization of the neutron activation analysis. (author)

  20. Investigation of the structure of ettringite by time-of-flight neutron powder diffraction techniques

    International Nuclear Information System (INIS)

    The crystalline structure of ettringite, Ca6[Al(OH)6]2(SO4)3.∼26H2O, was investigated using high-resolution time-of-flight neutron powder diffraction techniques. The powder diffraction data were subjected to Rietveld crystal structure refinement. The resultant ettringite crystal structure confirmed the positions of Ca, Al, and S atoms while permitting a more precise determination of the locations of O and H atomic positions than in previous X-ray and neutron diffraction studies. A discussion of the ettringite hydrogen bonding network is presented, illustrating the role of hydrogen bonding in the stabilization of the ettringite structure

  1. Calibrating and training of neutron based NSA techniques with less SNM standards

    Energy Technology Data Exchange (ETDEWEB)

    Geist, William H [Los Alamos National Laboratory; Swinhoe, Martyn T [Los Alamos National Laboratory; Bracken, David S [Los Alamos National Laboratory; Freeman, Corey R [Los Alamos National Laboratory; Newell, Matthew R [Los Alamos National Laboratory

    2010-01-01

    Accessing special nuclear material (SNM) standards for the calibration of and training on nondestructive assay (NDA) instruments has become increasingly difficult in light of enhanced safeguards and security regulations. Limited or nonexistent access to SNM has affected neutron based NDA techniques more than gamma ray techniques because the effects of multiplication require a range of masses to accurately measure the detector response. Neutron based NDA techniques can also be greatly affected by the matrix and impurity characteristics of the item. The safeguards community has been developing techniques for calibrating instrumentation and training personnel with dwindling numbers of SNM standards. Monte Carlo methods have become increasingly important for design and calibration of instrumentation. Monte Carlo techniques have the ability to accurately predict the detector response for passive techniques. The Monte Carlo results are usually benchmarked to neutron source measurements such as californium. For active techniques, the modeling becomes more difficult because of the interaction of the interrogation source with the detector and nuclear material; and the results cannot be simply benchmarked with neutron sources. A Monte Carlo calculated calibration curve for a training course in Indonesia of material test reactor (MTR) fuel elements assayed with an active well coincidence counter (AWCC) will be presented as an example. Performing training activities with reduced amounts of nuclear material makes it difficult to demonstrate how the multiplication and matrix properties of the item affects the detector response and limits the knowledge that can be obtained with hands-on training. A neutron pulse simulator (NPS) has been developed that can produce a pulse stream representative of a real pulse stream output from a detector measuring SNM. The NPS has been used by the International Atomic Energy Agency (IAEA) for detector testing and training applications at the

  2. On-line bulk elemental analysis in the resource industries using neutron-gamma techniques

    International Nuclear Information System (INIS)

    There is an increasing need in industry, arising from both economic and environmental considerations, to reduce costs and improve product quality through the use of automation. The use of on-line analysis instrumentation provides plant operators with a means for continuous measurement and rapid response. This can result in better control of process efficiency, product quality and resource utilization, all of which produce significant economic and environmental benefits. On-line measurement of bulk elemental composition is important in many industrial applications and is best achieved with highly penetrating neutron-gamma techniques. Recent work by CSIRO Minerals on the development and implementation of such a technique, NITA (neutron inelastic-scattering and thermal-capture analysis) is presented. NITA is distinct from the more common PGNAA (prompt neutron gamma activation analysis) technique in its use of fast neutron sources to generate inelastic scattering reactions, and in its consequent ability to excite gamma-rays from industrially important elements such as carbon and oxygen. Features of NITA and PGNAA analysers are compared and applications of NITA in industry, including the on-line analysis of composition in pyrometallurgical applications and the on-conveyor belt monitoring of cement raw meal and coal are discussed. (author)

  3. Neutron scattering at high temperature and levitation techniques

    International Nuclear Information System (INIS)

    Studies of the liquid state present an obvious fundamental interest and are also important for technological applications since the molten state is an essential stage in various industrial processes (e.g. glass making, single crystal growing, iron and steel making). Most of the physical properties of a high-temperature liquid are related to its atomic structure. Thus it is important to develop devices to probe the local environment of the atoms in the sample. At very high temperature, it is difficult to use conventional furnaces, which present several problems. In particular, physical contact with the container can contaminate the sample and/or modify its structural properties. Such problems encouraged the development of containerless techniques, which are powerful tools to study high-temperature melts. By eliminating completely any contact between sample and container, it is possible to study the sample with a very high degree of control and to access very high temperatures. An additional advantage of levitation methods is that it is possible to supercool hot liquids down to several hundred of degrees below their equilibrium freezing point, since heterogeneous nucleation processes are suppressed

  4. Determination of trace impurities of chlorine in zirconium-alloy matrices using neutron activation technique

    Energy Technology Data Exchange (ETDEWEB)

    Naik, H.; Nathaniel, T. Newton [Bhabha Atomic Research Centre, Trombay, Mumbai (India). Radiochemistry Div.; Sant, V.L. [Bhabha Atomic Research Centre, Trombay, Mumbai (India). Fuel Chemistry Div.; Suryanarayana, S.V. [Bhabha Atomic Research Centre, Trombay, Mumbai (India). Nuclear Physics Div.; Prajapati, P.M. [Bhabha Atomic Research Centre, Trombay, Mumbai (India). Reactor Physics Design Div.

    2011-07-01

    Trace impurities of chlorine in the zircaloy-2 and Zr-2.5% Nb alloy matrix have been determined using neutron activation analysis (NAA) and off-line {gamma}-ray spectrometric technique. The results have been compared with the values obtained from pyrohydrolysis-IC and spark source mass spectrometric method. The limit of internal precision error from the neutron activation technique is 6.7% for zircaloy-2 and 9% for Zr-2.5% Nb alloy, which are lower than that of pyrohydrolysis-IC and spark source mass spectrometric measurements respectively. For both alloys the results from present work based on NAA technique are slightly higher than the results based on the other two methods but are comparable within the uncertainty. Read More: http://www.oldenbourg-link.com/doi/abs/10.1524/ract.2011.1863 (orig.)

  5. The microscopic investigation of structures of moving flux lines by neutron and muon techniques

    Indian Academy of Sciences (India)

    E M Forgan; D Charalambous; P G Kealey

    2002-05-01

    We have used a variety of microscopic techniques to reveal the structure and motion of flux line arrangements, when the flux lines in low c type II superconductors are caused to move by a transport current. Using small-angle neutron scattering by the flux line lattice (FLL), we are able to demonstrate directly the alignment by motion of the nearest-neighbor FLL direction. This tends to be parallel to the direction of flux line motion, as had been suspected from two-dimensional simulations. We also see the destruction of the ordered FLL by plastic flow and the bending of flux lines. Another technique that our collaboration has employed is the direct measurement of flux line motion, using the ultra-high-resolution spectroscopy of the neutron spin-echo technique to observe the energy change of neutrons diffracted by moving flux lines. The muon spin rotation (SR) technique gives the distribution of values of magnetic field within the FLL. We have recently succeeded in performing SR measurements while the FLL is moving. Such measurements give complementary information about the local speed and orientation of the FLL motion. We conclude by discussing the possible application of this technique to thin film superconductors.

  6. Development of neutron interrogation techniques for detection of hazardous substances in containers port

    International Nuclear Information System (INIS)

    This work is aimed at contributing to the effort of nations seeking to control international borders movement of dangerous chemical substances and nuclear material, in accordance with a multitude of agreements signed to that purpose. At this stage, we try to identify the signature of pure substances: chlorine (Cl), nitrogen (N), chromium (Cr), mercury (Hg), cadmium (Cd), uranium (U) y arsenic (As) and, later, to detect their presence in simulated large cargo containers. The technique employed in previous and in current work, consists in the detection of prompt and early decay gammas induced by incident thermal neutrons or fast neutrons thermalized in the cargo array. Uranium has also been detected through the counting of fast neutrons originated in induced fissions. (author)

  7. Implementation of the neutron noise technique for subcritical reactors using a new data acquisition system

    International Nuclear Information System (INIS)

    A new data acquisition system was designed and programmed for nuclear kinetics parameter estimations in subcritical reactors. The system allows using any of the neutron noise techniques, since it could store the whole information available in the neutron detection system. The α Rossi, α Feynman and spectral analysis methods were performed in order to estimate the prompt neutron decay constant (and hence the reactivity). The measurements were done in the nuclear research reactor RA-1, where introducing the control rods, different reactivity levels where reached (until -7 dollars). With the three methods used, agreement was found between the estimations and the reference reactivities in each level, even when the detector efficiency was low. All the measurements were performed with a high gamma flux, although the results were found to be satisfactory. (author)

  8. Study of elastic and inelastic neutron cross-sections using time of flight technique

    International Nuclear Information System (INIS)

    High precision neutron scattering data has become increasingly important in the development of nuclear reactors and accelerator systems, astrophysics and space system design, radiation therapy and isotope production, and for shielding considerations. Previous evaluations of the neutron cross-section standards were completed in 1987 and disseminated as NEANDC/INDC and other databases. R-matrix model fits for the light elements and non-model least-squares fits for the heavy elements were the basis of the combined fits for all of the data. Some important reactions and constants are not considered standards, but assist greatly in the determination of the standard cross-sections and reduce their uncertainties. The focus of the present work is to measure elastic and inelastic neutron differential scattering cross-sections for 23Na using Time of Flight Technique for a range of energies with a high accuracy level

  9. New Techniques for Determining Spins and Parities of Neutron Resonances and Their Impact on Nuclear Astrophysics

    International Nuclear Information System (INIS)

    We describe new techniques for determining spins and parities of neutron resonances which have resulted in large improvements over previous methods. These advances have made it possible, for the first time, to obtain reduced-neutron- and total-radiation-width distributions separately for resonances of different spin and parity in odd-A target nuclides. Using these new as well as previous data, we show that neutron distributions sometimes are significantly different from the Porter-Thomas distribution assumed by the nuclear statistical model. Furthermore, we show that the radiation-width distributions often are substantially different than predicted by the nuclear statistical model using standard level densities and photon strength functions. These differences could have significant impact on astrophysical reaction rates calculated using the statistical model.

  10. Analysis of microstress in neutron irradiated polyester fibre by X-ray diffraction technique

    Indian Academy of Sciences (India)

    B Mallick; R C Behera; T Patel

    2005-10-01

    Microstresses developed in the crystallites of polymeric material due to irradiation of high-energy particle causes peak broadening and shifting of X-ray diffraction lines to lower angle. Neutron irradiation significantly changes the material properties by displacement of lattice atoms and the generation of helium and hydrogen by nuclear transmutation. Another important aspect of neutron irradiation is that the fast neutron can produce dense ionization at deep levels in the materials. The polyethylene terephthalate (PET) fibre of raw denier value, 78.2, were irradiated by fast neutron of energy, 4.44 MeV, at different fluences ranging from 1 × 109 n/cm2 to 1 × 1012 n/cm2. In the present work, the radiation heating microstresses developed in PET micro-crystallites was investigated applying X’Pert-MPD Philips Analytical X-ray diffractometer and the effects of microstresses in tensile strength of fibre measured by Instron have also been reported. The shift of 0.45 cm-1 in the Raman peak position of 1614.65 cm-1 to a higher value confirmed the development of microstresses due to neutron irradiation using micro-Raman technique. The defects due to irradiation were observed by SEM micrographs of single fibre for virgin and all irradiated samples.

  11. A distillation of the important physics for understanding neutron-based non-destructive assay techniques for nuclear fuel

    International Nuclear Information System (INIS)

    Since 2008, the US Department of Energy, through its Next Generation Safeguards Initiative (NGSI), has renewed the research of non-destructive-assay (NDA) techniques for determining the plutonium mass in spent nuclear fuel assemblies. Of the fourteen technologies that are being considered in the NGSI, ten technologies measure neutrons to determine the fissile content of the nuclear material. These ten techniques can be categorized according to the characteristic of the neutrons that they measure. Five techniques measure the multiplication of neutrons by fissile material, three analyze the neutron energy spectrum for resonance reactions in fissile isotopes, and two measure the time coincidence of the neutrons that are emitted by fission. A basic knowledge of these principles is essential for understanding these techniques. This paper summarizes parts of this knowledge. (author)

  12. Mosses as biomonitors to study the atmospheric deposition of heavy metals over the territory of Slovakia

    International Nuclear Information System (INIS)

    In regional trace element studies it is advantageous to determine as many elements as possible in order to better distinguish between different source categories. In the present work the moss bio-monitoring technique and the combination of two analytical techniques - epithermal neutron activation analysis (ENAA) and flame atomic absorption spectrometry (AAS) - were applied to elucidate these problems. The total concentrations of 44 individual elements were determined in 86 samples of mosses. The mean, median, standard deviation and range values was determined for each elements. The use of terrestrial mosses as bio monitors is a well-established technique in Europe Comparison with the current median level in Norway shows strong pollution of the examined areas of Slovakia with the most of heavy metals. Strongly elevated Pb values with compare even South Ural Maintains is evident. The Cd value is 1.5 to 9 times higher than in other Europeans regions, only concentration of Zn are approximately equally. The most important feature of the sampling is that it correlates with the European Moss-Survey-2000, and the results obtained will be incorporated in the Atlas of Heavy Metal Atmospheric Deposition in Europe. (authors)

  13. Non-destructive test of lock actuator component using neutron radiography technique

    International Nuclear Information System (INIS)

    Non-destructive test of lock actuator using neutron radiography technique has been done. The lock actuator is a mechanical system which is controlled by central lock module consisting of electronic circuit which drives the lock actuator works accordingly to open and lock the vehicle door. The non-destructive test using neutron radiography is carried out to identify the type of defect is presence by comparing between the broken and the brand new one. The method used to test the lock actuator component is film method (direct method). The result show that the radiography procedure has complied with the ASTM standard for neutron radiography with background density of 2.2, 7 lines and 3 holes was seen in the sensitivity indicator (SI) and the quite good image quality was obtained. In the brand new actuator is seen that isolator part which separated the coils has melted. By this non-destructive test using neutron radiography technique is able to detect in early stage the type of component's defect inside the lock actuator without to dismantle it. (author)

  14. Application of the pulsed neutron technique on the reactors ALIZE - AQUILON (1963)

    International Nuclear Information System (INIS)

    Different methods of measuring the ratio effective delayed fraction / prompt neutron lifetime, αc, are described. According to the classic pulsed neutron technique the negative reactivity due to a localized absorber is given by ρ / βeff = α / αc -1 Experiments are reported which show that in this case αc can not be considered constant for large reactivities. The absorber element distorts the flux in the system, increasing the importance of the reflector. An application of the pulsed neutron method to the measurement of critical distributed boron concentrations of various absorber elements is described. Less time is required than for the usual super-critical techniques, and the experimental analysis is simplified. It is interesting to note that the results are not influenced by the spectral sensitivity of the control element. A modified pulsed neutron method has been tried out. This procedure was used to determine by measurements at sub-critical the critical water level of uranium-heavy water lattices with a high precision. (author)

  15. Neutron Backscattered Technique for Quantification of Oil Palm Fruit Oil Content

    International Nuclear Information System (INIS)

    Non-destructive and real time method becomes a well-liked method to researchers in the oil palm industry since 2000. This method has the ability to detect oil content in order to increase the production of oil palm for better profit. Hence, this research investigates the potential of neutron source to estimate oil content in palm oil fruit since oil palm contains hydrogen with chemical formula C55H96O6. For this paper, oil palm loose fruit was being used and divided into three groups. These three groups are ripe, under-ripe and bruised fruit. A total of 21 loose fruit for each group were collected from a private plantation in Malaysia. Each sample was scanned using neutron backscattered technique. The higher neutron count, the more hydrogen content, and the more oil content in palm oil fruit. The best correlation result came from the ripe fruits with r2=0.98. This research proves that neutron backscattered technique can be used as a non-destructive and real time grading system for palm oil. (author)

  16. The role of neutron based inspection techniques in the post 9/11/01 era

    Science.gov (United States)

    Gozani, Tsahi

    2004-01-01

    Non-intrusive inspection of objects of all sizes, from luggage to shipping containers and from postal parcels to trucks is a vital component of any national security from aviation to the control of all land and sea ports of entries. The paramount importance of these inspections is more obvious now, in the post 9/11 era, as the spectrum of threats is wider and the probability of occurrence more real. The urgent need for reliable inspection underscores the key attributes they must possess: High specificity High sensitivity Provide automatic decision The technologies being currently employed in the field, such as standard X-ray, X-ray based computed tomography, and trace detection (for luggage), and X-ray or γ-ray based radiography (for containers) are inherently deficient for lacking some or all of these attributes. The neutron based technologies, on the other hand, possess all three. They provide therefore accurate, rapid and automatic detection of a wide array of threats: explosives, chemical agents, nuclear materials and devices, other hazardous materials, drugs, etc. The nuclear based techniques achieve this feat through the production of characteristic elemental gamma rays by nuclear reactions, primarily (n,γ) with thermal neutrons and (n,n 'γ) with fast neutrons. The principles and status of neutron based inspection techniques are reviewed below.

  17. Low-level measuring techniques for neutrons: High accuracy neutron source strength determination and fluence rate measurement at an underground laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Zimbal, Andreas; Reginatto, Marcel; Schuhmacher, Helmut; Wiegel, Burkhard [Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany); Degering, Detlev [Verein für Kernverfahrenstechnik und Analytik Rossendorf e. V. (VKTA), D-01314 Dresden (Germany); Zuber, Kai [Technische Universität Dresden, D-01069 Dresden (Germany)

    2013-08-08

    We report on measuring techniques for neutrons that have been developed at the Physikalisch-Technische Bundesanstalt (PTB), the German National Metrology Institute. PTB has characterized radioactive sources used in the BOREXINO and XENON100 experiments. For the BOREXINO experiment, a {sup 228}Th gamma radiation source was required which would not emit more than 10 neutrons per second. The determination of the neutron emission rate of this specially designed {sup 228}Th source was challenging due to the low neutron emission rate and because the ratio of neutron to gamma radiation was expected to be extremely low, of the order of 10{sup −6}. For the XENON100 detector, PTB carried out a high accuracy measurement of the neutron emission rate of an AmBe source. PTB has also done measurements in underground laboratories. A two month measurement campaign with a set of {sup 3}He-filled proportional counters was carried out in PTB's former UDO underground laboratory at the Asse salt mine. The aim of the campaign was to determine the intrinsic background of detectors, which is needed for the analysis of data taken in lowintensity neutron fields. At a later time, PTB did a preliminary measurement of the neutron fluence rate at the underground laboratory Felsenkeller operated by VKTA. By taking into account data from UDO, Felsenkeller, and detector calibrations made at the PTB facility, it was possible to estimate the neutron fluence rate at the Felsenkeller underground laboratory.

  18. The determination of pesticide residues in local vegetables by means of neutron activation technique

    International Nuclear Information System (INIS)

    Analytical methods based on neutron activation have been developed for studying pesticides residues of bromine, arsenic and mercury in local vegetables and fruits. The concentration of bromine, arsenic and mercury in samples are enriched prior to neutron irradiations by a technique of dry-ashing and freeze-drying for the determination of arsenic, bromine and mercury respectively. The element bromine is determined instrumentally while arsenic and mercury are determined destructively using a distillation technique. The limit of detection under the conditions used for bromine, arsenic and mercury as obtained are 0.01, 0.001 and 0.0001 microgram respectively. A total of 45 varieties of vegetables and 20 varieties of fruits are analyzed. The results of the investigation and the concentration range in part per million of bromine, arsenic and mercury are also presented

  19. Accessing Interior Vector Magnetic Field Components in Neutron EDM Experiments via Boundary Value Techniques

    Science.gov (United States)

    Plaster, Brad

    2012-10-01

    We propose a new technique for the determination and monitoring of the interior vector magnetic field components during the operation of neutron EDM experiments. If a suitable three-dimensional volume surrounding the fiducial volume of an experiment can be defined which contains no interior currents or magnetization, each of the interior vector field components will satisfy the Laplace Equation within this volume. Therefore, if the field components can be measured on the boundary, the interior vector field components can be determined uniquely via numerical solution of the Laplace Equation. We discuss the applicability of this technique to the determination of the magnetic field components and magnetic field gradients in the fiducial volumes of neutron EDM experiments.

  20. Efficacy of cranking technique in the study of some neutron-deficient neodymium isotopes

    International Nuclear Information System (INIS)

    In the present work, the results of calculations on various nuclear structure quantities in even-even neutron-deficient 130-136Nd using Cranked Hatree-Fock Bogoliubov (CHFB) technique have been presented. The various nuclear structure quantities that have been calculated in 130-136Nd isotopes are the yrast spectra, subshell occupation probabilities of various valence orbits and intrinsic quadrupole moments. Besides this, a comparative study of the calculated yrast spectra with the available experimental data as well as with the results of calculations obtained by R.K. Bhat et al. using Variation After Projection (VAP) technique on the same neutron-deficient 130-136Nd isotopes has also been presented

  1. Studies review and exploration purpose of neutron radiography technique in the TRIGA IPR-R1 reactor at CDTN, Brazil

    International Nuclear Information System (INIS)

    Neutron Radiography - NR - consists of obtaining on a sensitive plate, the image produced by neutron flux after crossing an object. Through NR is possible to inspect plastics and explosives materials and organic composition. Is difficult to analyze these materials by the radiography technique. The neutron beam extractor was installed, in the TRIGA IPR-R1 reactor at the CDTN. This work presents preliminaries results of the NR researches in the past at CDTN, which are being retaken. (author)

  2. Use of mosses as biomonitors of atmospheric deposition of trace elements

    International Nuclear Information System (INIS)

    Some basic facts about the use of mosses as biomonitors of atmospheric trace element deposition are reviewed, and advantages and limitations of this approach are discussed, largely on the basis of experience from regular use of this technique in Norway over the last 20 years. Topics discussed include different versions of the moss technique, mechanisms and efficiencies of trace element uptake, conversion of concentrations in moss to bulk deposition rates, and contribution from sources other than air pollution to the elemental composition of different elements. Suggestions are presented for further work in order to extend the use of mosses as biomonitors. (author)

  3. Manufacturing techniques studies of ceramics by neutron and γ-ray radiography

    International Nuclear Information System (INIS)

    In this study, the aim was to evaluate capabilities and constraints of radiographic imagery using thermal neutrons and gamma-rays as tools to identify the type of technique employed in ceramics manufacturing especially that used in prehistoric Brazilian pottery from Acre state. For this purpose, radiographic images of test objects made with clay of this region using both techniques - palette and rollers - have been acquired with a system comprised of a source of gamma-rays or thermal neutrons and a corresponding X-ray or neutron-sensitive Imaging Plate as detector. For the neutrongraphy samples were exposed to a thermal neutron flux of order of 105n.cm−2.s−1 for 3 minutes at main port of Argonauta research reactor of the Instituto de Engenharia Nuclear - IEN/CNEN. The radiographic images using γ-rays from 165Dy (95 keV) and 198Au (412 keV) both produced at this reactor, have been acquired under an exposure time of a couple of hours. After acquisition, images have undergone a treatment to improve their quality through enhancement of their contrast, a procedure involving corrections of the beam divergence, sample shape and averaging of the attenuation map profile. Preliminary results show that difference between manufacturing techniques is better identified by radiography using low energy γ-rays from 165Dy rather than neutrongraphy or γ-rays from 198Au. Nevertheless, disregarding the kind of employed radiation, it should be stressed that feasibility to apply the technique is tightly tied to homogeneity of the clay itself and tempers due to their different attenuation

  4. Determination of trace elements in tobacco using different techniques of neutron activation analysis

    International Nuclear Information System (INIS)

    Quantitative data on trace elements in two tobacco leaf (candidate) reference materials OTL-1 and VTL-2 prepared by the Polish Academy of Sciences and the Institute of Nuclear Chemistry and Technology, Warsaw, Poland, are presented and compared to recommended values, where available. By instrumental neutron activation analysis (INAA), as well as by radiochemical technique (RNAA) 30 elements were quantitatively determined and fair agreement was found between the results and recommended values for the first material. (author) 18 refs.; 5 tabs

  5. Manufacturing techniques studies of ceramics by neutron and γ-ray radiography

    Energy Technology Data Exchange (ETDEWEB)

    Latini, R. M.; Bellido, A. V. B. [Instituto de Química - Universidade Federal Fluminense (Brazil); Souza, M. I. S.; Almeida, G. L. [Instituto de Engenharia Nuclear (Brazil)

    2014-11-11

    In this study, the aim was to evaluate capabilities and constraints of radiographic imagery using thermal neutrons and gamma-rays as tools to identify the type of technique employed in ceramics manufacturing especially that used in prehistoric Brazilian pottery from Acre state. For this purpose, radiographic images of test objects made with clay of this region using both techniques - palette and rollers - have been acquired with a system comprised of a source of gamma-rays or thermal neutrons and a corresponding X-ray or neutron-sensitive Imaging Plate as detector. For the neutrongraphy samples were exposed to a thermal neutron flux of order of 10{sup 5}n.cm{sup −2}.s{sup −1} for 3 minutes at main port of Argonauta research reactor of the Instituto de Engenharia Nuclear - IEN/CNEN. The radiographic images using γ-rays from {sup 165}Dy (95 keV) and {sup 198}Au (412 keV) both produced at this reactor, have been acquired under an exposure time of a couple of hours. After acquisition, images have undergone a treatment to improve their quality through enhancement of their contrast, a procedure involving corrections of the beam divergence, sample shape and averaging of the attenuation map profile. Preliminary results show that difference between manufacturing techniques is better identified by radiography using low energy γ-rays from {sup 165}Dy rather than neutrongraphy or γ-rays from {sup 198}Au. Nevertheless, disregarding the kind of employed radiation, it should be stressed that feasibility to apply the technique is tightly tied to homogeneity of the clay itself and tempers due to their different attenuation.

  6. Theoretical challenges of determining low-energy neutron-capture cross sections via the Surrogate Technique

    International Nuclear Information System (INIS)

    Cross sections for radiative neutron capture on unstable nuclei at low energies are difficult to calculate with high precision, and can be impossible to measure directly. It is therefore important to explore alternative methods. The prospects of one such method, the Surrogate Nuclear Reaction Technique, is currently being investigated at Lawrence Livermore National Laboratory. The purpose of this paper is to outline the strategy for combining the results from a surrogate experiment with theoretical calculations in order to extract the desired cross section

  7. Determination of hydrogen content of petroleum products from Tema Oil Refinery using neutron backscatter technique

    International Nuclear Information System (INIS)

    The hydrogen content of hydrocarbon materials is very important in several areas of industrial process such as mining, vegetable oil extraction and crude oil exploration and refining. A fast and more universal technique based on thermal neutron reflection was employed to determine the total hydrogen contents of petroleum samples from Tema Oil Refinery (TOR) and Crude oil samples from Jubilee field and Nigeria. The experimental set-up consisted of a source-holder housing a 1Ci Am-Be neutron source and a He-3 neutron detector. Two geometrical arrangements were considered and their sensitivities were compared. The set-up was used to measure the excess neutron count in both geometrical considerations and their reflection parameters were calculated as a function of hydrogen content of the samples. Calibration lines were deduced using liquid hydrocarbons containing well-known hydrogen and carbon contents as standards. Two linear equations were generated from the calibration lines and were used to further determine the hydrogen content of thirteen (13) petroleum samples obtained from Quality Control Department of TOR. The total hydrogen contents were found to be in the range of 7.211(hw %) - 15.069 (hw %) for vertical geometry and 7.206 (hw %) - 14.948 (hw %) for horizontal geometry respectively. The results obtained agreed constructively with other results obtained using different methodologies by other studies. The percentage error of the hydrogen contents denoted by (% E) for the various petroleum samples were also obtained and noticed to be within an acceptable range. The neutron backscatter technique was observed as an alternative and more generalized method for quality assurance and standardization in the petroleum industries

  8. Application of neutron induced radiography technique in determination of boron in aluminium

    International Nuclear Information System (INIS)

    The technique of Neutron Induced Radiography has been applied to determine boron concentration and its spatial distribution in aluminium using Allyl diglycol carbonate (CR-39) detectors. The technique is based upon the simultaneous irradiation of sample and a standard fixed on a track detector with thermal neutrons and the counting of alpha and /sup 7/Li tracks produced in the detector from the nuclear reaction /sup 10/B(n,α)/sup 7/Li after chemical etching. Boron concentration is determined by comparing the /sup 7/Li and alpha particle tracks density with that of a standard of known boron concentration. Boron concentration in aluminium has been found to be (135.8 ±0.7) ppm in this study which is on the higher side within the normal range reported in the literature. The technique of boron determination by Neutron Induced Radiography is a simple and reliable. It can be used to study the other α-emitting radionuclides in minerals and other materials. (author)

  9. Genetic algorithms - A new technique for solving the neutron spectrum unfolding problem

    International Nuclear Information System (INIS)

    A new technique utilizing genetic algorithms has been applied to the Bonner sphere neutron spectrum unfolding problem. Genetic algorithms are part of a relatively new field of 'evolutionary' solution techniques that mimic living systems with computer-simulated 'chromosome' solutions. Solutions mate and mutate to create better solutions. Several benchmark problems, considered representative of radiation protection environments, have been evaluated using the newly developed UMRGA code which implements the genetic algorithm unfolding technique. The results are compared with results from other well-established unfolding codes. The genetic algorithm technique works remarkably well and produces solutions with relatively high spectral qualities. UMRGA appears to be a superior technique in the absence of a priori data - it does not rely on 'lucky' guesses of input spectra. Calculated personnel doses associated with the unfolded spectra match benchmark values within a few percent

  10. Application of neutron radiography technique in the explosives and pyrotechnical components inspection

    International Nuclear Information System (INIS)

    The IPEN-CNEN/SP and the IAE/CTA performed a study concerning the quality control of pyrotechnic devices and explosives employed in rocket and satellite, by means of the neutron radiography technique. The radiographs were performed in a facility installed at the radial beam hole 08 of the IEA-R1 Nuclear Research Reactor of the IPEN-CNEN/SP. The results were evaluated by visual inspection as well as by digital image processing and demonstrated the techniques viability for this purpose and an improvement of the quality results due to this processing. (author). 8 refs, 5 figs, 1 tab

  11. Monte Carlo parametric studies of neutron interrogation with the Associated Particle Technique for cargo container inspections

    Science.gov (United States)

    Deyglun, Clément; Carasco, Cédric; Pérot, Bertrand

    2014-06-01

    The detection of Special Nuclear Materials (SNM) by neutron interrogation is extensively studied by Monte Carlo simulation at the Nuclear Measurement Laboratory of CEA Cadarache (French Alternative Energies and Atomic Energy Commission). The active inspection system is based on the Associated Particle Technique (APT). Fissions induced by tagged neutrons (i.e. correlated to an alpha particle in the DT neutron generator) in SNM produce high multiplicity coincidences which are detected with fast plastic scintillators. At least three particles are detected in a short time window following the alpha detection, whereas nonnuclear materials mainly produce single events, or pairs due to (n,2n) and (n,n'γ) reactions. To study the performances of an industrial cargo container inspection system, Monte Carlo simulations are performed with the MCNP-PoliMi transport code, which records for each neutron history the relevant information: reaction types, position and time of interactions, energy deposits, secondary particles, etc. The output files are post-processed with a specific tool developed with ROOT data analysis software. Particles not correlated with an alpha particle (random background), counting statistics, and time-energy resolutions of the data acquisition system are taken into account in the numerical model. Various matrix compositions, suspicious items, SNM shielding and positions inside the container, are simulated to assess the performances and limitations of an industrial system.

  12. Neutron imaging with coded sources: new challenges and the implementation of a simultaneous iterative reconstruction technique

    Energy Technology Data Exchange (ETDEWEB)

    Santos-Villalobos, Hector J [ORNL; Bingham, Philip R [ORNL; Gregor, Jens [University of Tennessee, Knoxville (UTK)

    2013-01-01

    The limitations in neutron flux and resolution (L/D) of current neutron imaging systems can be addressed with a Coded Source Imaging system with magnification (xCSI). More precisely, the multiple sources in an xCSI system can exceed the flux of a single pinhole system for several orders of magnitude, while maintaining a higher L/D with the small sources. Moreover, designing for an xCSI system reduces noise from neutron scattering, because the object is placed away from the detector to achieve magnification. However, xCSI systems are adversely affected by correlated noise such as non-uniform illumination of the neutron source, incorrect sampling of the coded radiograph, misalignment of the coded masks, mask transparency, and the imperfection of the system Point Spread Function (PSF). We argue that a model-based reconstruction algorithm can overcome these problems and describe the implementation of a Simultaneous Iterative Reconstruction Technique algorithm for coded sources. Design pitfalls that preclude a satisfactory reconstruction are documented.

  13. Enhanced Analysis Techniques for an Imaging Neutron and Gamma Ray Spectrometer

    Science.gov (United States)

    Madden, Amanda C.

    The presence of gamma rays and neutrons is a strong indicator of the presence of Special Nuclear Material (SNM). The imaging Neutron and gamma ray SPECTrometer (NSPECT) developed by the University of New Hampshire and Michigan Aerospace corporation detects the fast neutrons and prompt gamma rays from fissile material, and the gamma rays from radioactive material. The instrument operates as a double scatter device, requiring a neutron or a gamma ray to interact twice in the instrument. While this detection requirement decreases the efficiency of the instrument, it offers superior background rejection and the ability to measure the energy and momentum of the incident particle. These measurements create energy spectra and images of the emitting source for source identification and localization. The dual species instrument provides superior detection than a single species alone. In realistic detection scenarios, few particles are detected from a potential threat due to source shielding, detection at a distance, high background, and weak sources. This contributes to a small signal to noise ratio, and threat detection becomes difficult. To address these difficulties, several enhanced data analysis tools were developed. A Receiver Operating Characteristic Curve (ROC) helps set instrumental alarm thresholds as well as to identify the presence of a source. Analysis of a dual-species ROC curve provides superior detection capabilities. Bayesian analysis helps to detect and identify the presence of a source through model comparisons, and helps create a background corrected count spectra for enhanced spectroscopy. Development of an instrument response using simulations and numerical analyses will help perform spectra and image deconvolution. This thesis will outline the principles of operation of the NSPECT instrument using the double scatter technology, traditional analysis techniques, and enhanced analysis techniques as applied to data from the NSPECT instrument, and an

  14. Development, improvement and calibration of neutronic reaction rates measurements: elaboration of a standard techniques basis

    International Nuclear Information System (INIS)

    In order to improve and to validate the neutronics calculation schemes, perfecting integral measurements of neutronics parameters is necessary. This thesis focuses on the conception, the improvement and the development of neutronics reaction rates measurements, and aims at building a base of standard techniques. Two subjects are discussed. The first one deals with direct measurements by fission chambers. A short presentation of the different usual techniques is given. Then, those last ones are applied through the example of doubling time measurements on the EOLE facility during the MISTRAL 1 experimental programme. Two calibration devices of fission chambers are developed: a thermal column located in the central part of the MINERVE facility, and a calibration cell using a pulsed high flux neutron generator and based on the discrimination of the energy of the neutrons with a time-of-flight method. This second device will soon allow to measure the mass of fission chambers with a precision of about 1 %. Finally, the necessity of those calibrations will be shown through spectral indices measurements in core MISTRAL 1 (UO2) and MISTRAL 2 (MOX) of the EOLE facility. In each case, the associated calculation schemes, performed using the Monte Carlo MCNP code with the ENDF-BV library, will be validated. Concerning the second one, the goal is to develop a method for measuring the modified conversion ratio of 238U (defined as the ratio of 238U capture rate to total fission rate) by gamma-ray spectrometry of fuel rods. Within the framework of the MISTRAL 1 and MISTRAL 2 programmes, the measurement device, the experimental results and the spectrometer calibration are described. Furthermore, the MCNP calculations of neutron self-shielding and gamma self-absorption are validated. It is finally shown that measurement uncertainties are better than 1 %. The extension of this technique to future modified conversion ratio measurements for 242Pu (on MOX rods) and 232Th (on Thorium rods

  15. Development, improvement and calibration of neutronic reaction rate measurements: elaboration of a base of standard techniques

    International Nuclear Information System (INIS)

    In order to improve and to validate the neutronic calculation schemes, perfecting integral measurements of neutronic parameters is necessary. This thesis focuses on the conception, the improvement and the development of neutronic reaction rates measurements, and aims at building a base of standard techniques. Two subjects are discussed. The first one deals with direct measurements by fission chambers. A short presentation of the different usual techniques is given. Then, those last ones are applied through the example of doubling time measurements on the EOLE facility during the MISTRAL 1 experimental programme. Two calibration devices of fission chambers are developed: a thermal column located in the central part of the MINERVE facility, and a calibration cell using a pulsed high flux neutron generator and based on the discrimination of the energy of the neutrons with a time-of-flight method. This second device will soon allow to measure the mass of fission chambers with a precision of about 1 %. Finally, the necessity of those calibrations will be shown through spectral indices measurements in core MISTRAL 1 (UO2) and MISTRAL 2 (MOX) of the EOLE facility. In each case, the associated calculation schemes, performed using the Monte Carlo MCNP code with the ENDF-BV library, will be validated. Concerning the second one, the goal is to develop a method for measuring the modified conversion ratio of 238U (defined as the ratio of 238U capture rate to total fission rate) by gamma-ray spectrometry of fuel rods. Within the framework of the MISTRAL 1 and MISTRAL 2 programmes, the measurement device, the experimental results and the spectrometer calibration are described. Furthermore, the MCNP calculations of neutron self-shielding and gamma self-absorption are validated. It is finally shown that measurement uncertainties are better than 1 %. The extension of this technique to future modified conversion ratio measurements for 242Pu (on MOX rods) and 232Th (on Thorium rods

  16. Second international comparison on measuring techniques of tritium production rate for fusion neutronics experiments (ICMT-2)

    International Nuclear Information System (INIS)

    An second international comparison on measuring techniques of tritium production rates for fusion neutronics experiments (ICMT-2) has been performed. The purpose is to evaluate the measurement accuracy of tritium production rates in the current measurement techniques. Two 14 MeV neutron source facilities, FNS at JAERI-Japan and LOTUS at EPFL-Switzerland, were used for this purpose. Nine groups out of seven countries participated in this program. A fusion simulated blanket assembly of simple-geometry was served as the test bed at each facility, in which Li-containing samples from the participants were irradiated in an uniform neutron field. The tritium production rates were determined by the participants using their own ways by using the liquid scintillation counting method. Tritiated water sample with unknown but the same concentration was also distributed and its concentration was measured to make a common reference. The standard deviation of measured tritium production rates among participants was about 10 % for both FNS and LOTUS irradiation levels: 4x10-13 T-atoms/Li-atom and 1.6x10-12 T-atoms/Li-atom at a sample, respectively. This standard deviation exceeds the expected deviation of 5 % in this program. It is presumed that the deviation of 10 % is caused mainly by the systematic and unknown errors in a process of tritium extraction from the irradiated samples depending on each organization. (author)

  17. Combination of Magnetic Susceptibility, Electromagnetic and Neutron Backscattering Techniques for Land mine Detection

    International Nuclear Information System (INIS)

    Current research focuses on the use of multiple sensors for land mine detection, as opposed to approach which use a single sensor. Magnetic and electromagnetic methods are perhaps the most convenient and popular geophysical survey methods for detecting buried manmade metallic objects; which are due to their non-intrusiveness, high survey speed and quality of information. Meanwhile, the neutron backscattering method can detect the explosive materials in the land mine, which cannot detect by the two mentioned methods. An experimental study has been conducted using the three techniques to determine the minimum lateral resolving distance between two adjacent land mines and to detect the buried situated at deeper depths. The results showed that the magnetic susceptibility and neutron backscattering methods have a minimum lateral resolving distance of about 40 cm while, they have a limited penetration depth. Meanwhile, the horizontal-loop electromagnetic (HLEM) method has a relatively wider lateral resolving distance but it can detect the buried metallic object to several meters depths. Therefore, such combination of the three mentioned methods to detect the land mine yields more information about the type, lateral resolving distance between two adjacent land mines and depth of the buried land mines than is obtain, when each method is used individually. Also, such results will help greatly in evaluating any multi-sensors detection approach of magnetic susceptibility, electromagnetic and neutron backscattering techniques

  18. The VALMONT Program: Accurate experimental techniques to support the neutronics qualification of UMo/AL

    International Nuclear Information System (INIS)

    The VALMONT program aimed at qualifying the HORUS3D (HOrowitz Reactor simulation Unified System) neutronics calculation route that is used for the development of the JHR core, and to verify the correct treatment of UMo/Al (20% enrichment in 235U) fuel. The program is composed of two parts. The first part was devoted to the measurement by the oscillation technique of the reactivity effect of UAl/Mo fuel with an accuracy around 1% (1□). The second part consisted of gamma-spectroscopy experiments on a dedicated UMo/Al fuel sample in order to characterize, through axial power profiles and modified conversion ratio of 238U measurements, the production and absorption effects inside the UAl/Mo fuel. The overall excellent agreement between high accuracy experiments and calculations allowed to qualify the HORUS3D neutronics calculation route for UMo/Al fuel. (author)

  19. Investigation of Lecturer's Chalk by X-Ray Florescence and Fast Neutron Activation Techniques

    International Nuclear Information System (INIS)

    Different samples of lecturer's chalk were studied, using X-ray florescence (XRF) and Fast Neutron Activation Analysis (FNAA) techniques to ensure the safety of its use. The K (X-rays) and the gamma-rays were measured, using Si(Li) and high-purity germanium (HPGe) spectrometers to detect and determine qualitatively and quantitatively the constituents of the studied samples. For the investigated bulk chalk samples, the XRF was used for determination the average neutron flux of 2×107 n/cm2 sec. The concentrations of the elements (Ca and small traces of Al, Fe, Mg and Si) were measured and their presence was confirmed by γ-ray, lifetime and/or XRF measurements.

  20. Investigating the Defect Structures in Transparent Conducting Oxides Using X-ray and Neutron Scattering Techniques

    Directory of Open Access Journals (Sweden)

    Gabriela B. González

    2012-05-01

    Full Text Available Transparent conducting oxide (TCO materials are implemented into a wide variety of commercial devices because they possess a unique combination of high optical transparency and high electrical conductivity. Created during the processing of the TCOs, defects within the atomic-scale structure are responsible for their desirable optical and electrical properties. Therefore, studying the defect structure is essential to a better understanding of the behavior of transparent conductors. X-ray and neutron scattering techniques are powerful tools to investigate the atomic lattice structural defects in these materials. This review paper presents some of the current developments in the study of structural defects in n-type TCOs using x-ray diffraction (XRD, neutron diffraction, extended x-ray absorption fine structure (EXAFS, pair distribution functions (PDFs, and x-ray fluorescence (XRF.

  1. Software development of the mechanical vibration monitoring system of the CNA I reactor internals by neutron noise technique

    International Nuclear Information System (INIS)

    The neutron noise analysis technique is an important predictive maintenance tool for early detection of failures such as sensor malfunctions and incipient mechanical problems located in the reactor internals. This technique was applied successfully in Argentina since 1987. The FER-GAEN group dependent of the CNEA developed the measuring system to detect anomalies as early as possible. The magnitude of interest in this analysis is the fluctuating component of the neutron flux known as 'neutron noise'. In order to improve and facilitate the analysis, a new software code was developed for the data acquisition of the neutron noise signals and neutron spectra estimation in the frequency domain. The RMS values related with the internals vibrations are calculated from these spectra and are chronologically displayed, in order to detect any anomalous vibration or incipient detector malfunction as early as possible. (author)

  2. Advanced Penning-type ion source development and passive beam focusing techniques for an associated particle imaging neutron generator

    OpenAIRE

    Sy, Amy

    2013-01-01

    The use of accelerator-based neutron generators for non-destructive imaging and analysis in commercial and security applications is continuously under development, with improvements to available systems and combinations of available techniques revealing new capabilities for real-time elemental and isotopic analysis. The recent application of associated particle imaging (API) techniques for time- and directionally-tagged neutrons to induced fission and transmission imaging methods demonstrate...

  3. Development of a novel neutron detection technique by using a boron layer coating a Charge Coupled Device

    OpenAIRE

    Blostein, Juan Jerónimo; Estrada, Juan; Tartaglione, Aureliano; Haro, Miguel Sofo; Moroni, Guillermo Fernández; Cancelo, Gustavo

    2014-01-01

    This article describes the design features and the first test measurements obtained during the installation of a novel high resolution 2D neutron detection technique. The technique proposed in this work consists of a boron layer (enriched in ${^{10}}$B) placed on a scientific Charge Coupled Device (CCD). After the nuclear reaction ${^{10}}$B(n,$\\alpha$)${^{7}}$Li, the CCD detects the emitted charge particles thus obtaining information on the neutron absorption position. The above mentioned io...

  4. Foote Brook Macroinvertebrate Biomonitoring-Phase I in Johnson, Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — The Foote Brook Biomonitoring Project, Phase I geospatial dataset consists of data from the biomonitoring of benthic macroinvertebrates at three sites located along...

  5. Neutron, fluorescence, and optical imaging: An in situ combination of complementary techniques

    International Nuclear Information System (INIS)

    An apparatus which enables the simultaneous combination of three complementary imaging techniques, optical imaging, fluorescence imaging, and neutron radiography, is presented. While each individual technique can provide information on certain aspects of the sample and their time evolution, a combination of the three techniques in one setup provides a more complete and consistent data set. The setup can be used in transmission and reflection modes and thus with optically transparent as well as opaque samples. Its capabilities are illustrated with two examples. A polymer hydrogel represents a transparent sample and the diffusion of fluorescent particles into and through this polymer matrix is followed. In reflection mode, the absorption of solvent by a nile red-functionalized mesoporous silica powder and the corresponding change in fluorescent signal are studied

  6. Neutron, fluorescence, and optical imaging: An in situ combination of complementary techniques.

    Science.gov (United States)

    Wagner, D; Börgardts, M; Grünzweig, C; Lehmann, E; Müller, T J J; Egelhaaf, S U; Hermes, H E

    2015-09-01

    An apparatus which enables the simultaneous combination of three complementary imaging techniques, optical imaging, fluorescence imaging, and neutron radiography, is presented. While each individual technique can provide information on certain aspects of the sample and their time evolution, a combination of the three techniques in one setup provides a more complete and consistent data set. The setup can be used in transmission and reflection modes and thus with optically transparent as well as opaque samples. Its capabilities are illustrated with two examples. A polymer hydrogel represents a transparent sample and the diffusion of fluorescent particles into and through this polymer matrix is followed. In reflection mode, the absorption of solvent by a nile red-functionalized mesoporous silica powder and the corresponding change in fluorescent signal are studied. PMID:26429447

  7. Neutron, fluorescence, and optical imaging: An in situ combination of complementary techniques

    Science.gov (United States)

    Wagner, D.; Börgardts, M.; Grünzweig, C.; Lehmann, E.; Müller, T. J. J.; Egelhaaf, S. U.; Hermes, H. E.

    2015-09-01

    An apparatus which enables the simultaneous combination of three complementary imaging techniques, optical imaging, fluorescence imaging, and neutron radiography, is presented. While each individual technique can provide information on certain aspects of the sample and their time evolution, a combination of the three techniques in one setup provides a more complete and consistent data set. The setup can be used in transmission and reflection modes and thus with optically transparent as well as opaque samples. Its capabilities are illustrated with two examples. A polymer hydrogel represents a transparent sample and the diffusion of fluorescent particles into and through this polymer matrix is followed. In reflection mode, the absorption of solvent by a nile red-functionalized mesoporous silica powder and the corresponding change in fluorescent signal are studied.

  8. Joining techniques development for neutron irradiation tests and post irradiation examinations in JMTR-HL

    International Nuclear Information System (INIS)

    The hot laboratory (JMTR-HL) associated with the JMTR (Japan Materials Testing Reactor) was founded to examine the material and fuel specimens irradiated mainly in the JMTR. Through the post-irradiation examinations (PIEs) have been developed and performed, the JMTR-HL contributes not only to research of materials for light water reactors, fast reactors, high temperature gas reactor, and fusion reactor, but also to production of domestic industrial radio isotopes like 192Ir. As the part of PIE technology development, several kinds of welding techniques have been systematically developed. These research and development of welding techniques such as circumference and sealing for irradiation capsules and rewelding with irradiated materials were implemented under the remote-controlled conditions in the hot cells. These techniques are very indispensable for the neutron irradiation tests and PIEs to be conducted in the JMTR. (author)

  9. Neutron, fluorescence, and optical imaging: An in situ combination of complementary techniques

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, D.; Egelhaaf, S. U.; Hermes, H. E. [Condensed Matter Physics Laboratory, Heinrich Heine University, 40225 Düsseldorf (Germany); Börgardts, M.; Müller, T. J. J. [Institute for Organic and Macromolecular Chemistry, Heinrich Heine University, 40225 Düsseldorf (Germany); Grünzweig, C.; Lehmann, E. [Neutron Imaging and Activation Group, Paul Scherrer Institute, 5232 Villigen (Switzerland)

    2015-09-15

    An apparatus which enables the simultaneous combination of three complementary imaging techniques, optical imaging, fluorescence imaging, and neutron radiography, is presented. While each individual technique can provide information on certain aspects of the sample and their time evolution, a combination of the three techniques in one setup provides a more complete and consistent data set. The setup can be used in transmission and reflection modes and thus with optically transparent as well as opaque samples. Its capabilities are illustrated with two examples. A polymer hydrogel represents a transparent sample and the diffusion of fluorescent particles into and through this polymer matrix is followed. In reflection mode, the absorption of solvent by a nile red-functionalized mesoporous silica powder and the corresponding change in fluorescent signal are studied.

  10. Assessment of the traffic-related elements Ba, Cr and Zn during and after the construction of a peripheral highway using Tillandsia usneoides as atmospheric biomonitor

    Energy Technology Data Exchange (ETDEWEB)

    Figueiredo, Ana M.G.; Silva, Barbara C. da, E-mail: anamaria@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Nievola, Catarina C.; Alves, Edenise S.; Domingos, Marisa, E-mail: ccnievola@uol.com.br, E-mail: ealves@ibot.sp.gov.br, E-mail: mmingos@superig.com.br [Instituto de Botanica de Sao Paulo, Sao Paulo, SP (Brazil)

    2013-07-01

    Tillandsia usneoides (L.) L. is an aerial epiphytic bromeliad that lives on trees or other kinds of inert substratum, absorbing water and nutrients directly from the environment. Due to this characteristic, this species also accumulates pollutants present in the atmosphere. In this study, T. usneoides was used as biomonitor aiming to verify if the construction of the western and southern parts of the peripheral highway Mario Covas (SP-21) in Sao Paulo city would alter the profile of atmospheric contamination by Ba, Cr and Zn in the region. These elements are often associated with traffic and can indicate contaminated urban areas. This knowledge is of great interest to the city, which has one of the biggest vehicle fleets in the world, with more than seven million circulating motor vehicles and serious environmental problems due to air pollution. Neutron Activation Analysis was employed as analytical technique. Samples of T. usneoides were irradiated at the IEA-R1 nuclear reactor at IPEN-CNEN/SP, and the induced activity was measured by high resolution gamma-ray spectrometry. Increasing concentrations of Ba, Cr and Zn were observed in the biomonitor after the inauguration of the highway, indicating that these elements originated from vehicular emissions. (author)

  11. Development of measurement technique for lattice spacing at strain free by neutron diffraction method

    International Nuclear Information System (INIS)

    For precise stress analysis of engineering materials by diffraction methods, lattice spacing of strain-free materials, d0, must be accurately measured and estimated. Powder diffraction method is a general way of determining the d0. However, preparation of high quality powder sample is actually difficult in that labor, time, knowledge, and technique are required. In this study, we propose a new easy technique of measuring the sample as original process material instead of the powder diffraction method for estimation of accurate d0. The d0 obtained by our technique is estimated from the dAve which is the average of d measured while turning the sample material at random. The strain-free lattice constant, a0, is calculated from dAve(hkl) of some diffraction planes by the extrapolation method. The d0(hkl) of each diffraction plane is converted from this a0. In own method, the d0(hkl) of the extra super duralumin which have the structure of the texture was measured. To examine the reliability of this new method, the d0(hkl) obtained by own method was compared with the d0(hkl) of powder estimated by the general methods which is neutron and X-ray diffraction method. These differences were 8.7 x 10-6nm or less. These values become 10MPa or less for the stress. This result confirmed that present method could calculate d0(hkl) with enough accuracy for the neutron residual stress analysis. (author)

  12. Dynamic neutron computer tomography technique for velocity measurement in liquid metal flow - Fundamental PTV experiment -

    International Nuclear Information System (INIS)

    The aim of this development is to visualize and measure the velocity distribution in liquid metal flow using the neutron beam with the high-speed imaging technique, computer tomography (CT) technique and particle tracking velocimetry (PTV). Final research purpose is to obtain the velocity distribution and flow profile data of liquid metal flow in a heated rod bundle for development of the advanced fast breeder reactor (FBR) core. In this paper, visualization and measurement method using the high intensity and large size neutron beam port of the research reactor JRR-4, design and manufacturing of the experimental apparatus, spring model PTV method for this technique and results of the fundamental PTV experiment were reported. The test section for the fundamental experiment was a revolving aluminum column with cadmium tracers which simulated the liquid metal flow. As the result, cadmium tracers buried in the column with the speed of 1.5 revolving per second could be visualized as the 3D movie under 125Hz and 250Hz sampling conditions, the profile of the tracer could be traced, and fundamental velocity distribution measurement method could be conformed.

  13. A neutron-X-ray, NMR and calorimetric study of glassy Probucol synthesized using containerless techniques

    Energy Technology Data Exchange (ETDEWEB)

    Weber, J.K.R., E-mail: rweber@anl.gov [Materials Development, Inc., Arlington Heights, IL 60004 (United States); Argonne National Laboratory, Argonne, IL 60439 (United States); Benmore, C.J. [Argonne National Laboratory, Argonne, IL 60439 (United States); Department of Physics, Arizona State University, AZ 85287 (United States); Tailor, A.N.; Tumber, S.K. [Materials Development, Inc., Arlington Heights, IL 60004 (United States); Neuefeind, J. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Cherry, B. [Magnetic Resonance Research Center, Arizona State University, AZ 85287 (United States); Department of Chemistry and Biochemistry, Arizona State University, AZ 85287 (United States); Yarger, J.L. [Department of Physics, Arizona State University, AZ 85287 (United States); Magnetic Resonance Research Center, Arizona State University, AZ 85287 (United States); Department of Chemistry and Biochemistry, Arizona State University, AZ 85287 (United States); Mou, Q. [Magnetic Resonance Research Center, Arizona State University, AZ 85287 (United States); Department of Chemistry and Biochemistry, Arizona State University, AZ 85287 (United States); Weber, W. [Department of Physics, Arizona State University, AZ 85287 (United States); Department of Chemistry and Biochemistry, Arizona State University, AZ 85287 (United States); Byrn, S.R. [Department of Industrial and Physical Pharmacy, Purdue University, IN 47907 (United States)

    2013-10-16

    Highlights: • Acoustic levitation was used to make phase-pure glassy forms of pharmaceutical compounds. • Neutrons, X-rays and NMR were used to characterize the glasses. • The glass comprised of slightly distorted molecules packed in a random network. • Potential for new drug synthesis routes is discussed. - Abstract: Acoustic levitation was used to trap 1–3 mm diameter drops of Probucol and other pharmaceutical materials in containerless conditions. Samples were studied in situ using X-ray diffraction and ex situ using neutron diffraction, NMR and DSC techniques. The materials were brought into non-equilibrium states by supersaturating solutions or by supercooling melts. The glass transition and crystallization temperatures of glassy Probucol were 29 ± 1 and 71 ± 1 °C respectively. The glassy form was stable with a shelf life of at least 8 months. A neutron/X-ray difference function of the glass showed that while molecular sub-groups remain rigid, many of the hydrogen correlations observed in the crystal become smeared out in the disordered material. The glass is principally comprised of slightly distorted Form I Probucol molecules with disordered packing rather than large changes in the individual molecular structure. Avoiding surface contact-induced nucleation provided access to highly non-equilibrium phases and enabled synthesis of phase-pure glasses.

  14. Profiling water content in soils with TDR: Comparison with the neutron probe technique

    International Nuclear Information System (INIS)

    In November 1996, at a site on the Grenoble campus a 1.2-m-long neutron access tube, a 0.8-m fibreglass Trime access tube and three sets of 1-m twin-rod TDR probes were installed. Weekly measurements were made over a 9-month period. In addition, soil samples were taken from time to time with an auger, to determine gravimetric water-contents. The soil bulk density profile was initially characterised by gammametry using a CampbellTM probe. A TroxlerTM 4300 was used for the neutron-probe measurements. The TDR signals, for further processing by TDR-SSI, were logged using a Trase 2000 from Soil Moisture Equipment CorporationTM. TDR methods were employed without any special calibration of the permittivity/water-content relationship: standard internal calibrations of the devices or Topp polynomial relation were always applied. The results of all these water-content profiling methods were compared in three ways: (i) the water-content profiles were plotted directly on the same graph for different dates; (ii) all the water contents measured at all dates and all depths were plotted against a corresponding 'reference', namely neutron probe or gravimetry; (iii) water balances were calculated for each method and their respective time-profiles analysed. There was fairly good agreement among the three profiling methods, indicating that TDR is now a viable alternative to nuclear techniques for soil water-content profiling. (author)

  15. Kinetic parameters estimation in research reactors by means of the neutron noise technique

    International Nuclear Information System (INIS)

    This work shows the application of the neutron noise technique for the kinetic parameters estimation in research reactors. It presents the results obtained for the prompt neutron constant 'α' in the research reactors RA-0, RA-1, RA-3, RA-4, RA-6 and RA-8. This important parameter is used in safety analysis and neutron codes validation. The ionization chambers (CI1, CI2) were located close to the reactor core, in order to have a high absolute efficiency with the purpose of obtaining a high precision value of 'α'. It was applied a method based in data fit of the power spectral density, which estimates the absolute efficiency 'ε' of CI1 and CI2 as well as the thermal power. In addition, a second method based in the called 'Autoregressive Moving Average Model' (ARMA) was applied for the first time in the research reactors of CNEA. A comparative study of both methods, is presented for a set of measurements performed in the RA-1 reactor for high and low absolute efficiency. In the case of high efficiency, the estimation of 'α' obtained form both methods was coincident. For the low efficiency case both estimations of 'α' differ approximately in a 30 % by defect with respect to the value obtained in the case of high efficiency. (author)

  16. Exchange biasing studied by neutron techniques in Fe3O4/CoO multilayers

    International Nuclear Information System (INIS)

    Complete text of publication follows. Recently, the interest in exchange biasing (i.e. the coupling between the antiferromagnetic (AF) and ferromagnetic (F) layers) surged, due to its relevance for GMR spin-valves. Using Fe3O4/CoO as a model system, it is shown how neutron techniques are crucial in unraveling the nature of the coupling at the buried AF-F interface. Neutron diffraction has shown that the coupling at the interface is not collinear as thus far assumed but perpendicular [1], in agreement with the recent theory by Koon [2]. However, further study by a.o. high- and low-angle neutron diffraction shows that no parallel AF domain wall (can) exists within the AF-layer as assumed by Koon. This suggests that the recent theory by Schulthess-Butler, which finds a perpendicular AF-F coupling on the basis of roughness and a perpendicular domain wall formation in the AF [3], might offer a better framework to understand biasing. The issue of TN in ultrathin CoO layers and its connection to the reduction of the blocking temperature observed in biased AF/F bilayers are also discussed. (author)

  17. Neutron radiography, a technique for studying young roots growing in soil

    International Nuclear Information System (INIS)

    The indirect technique for taking neutron radiographs using indium collector foils has been used to study root growth into soils. The work was done at Ames Laboratory Research Reactor, Iowa, USA, where a neutron beam of 107 n.cm-2.s-1 was available and 5x109 n.cm-1 were needed to obtain satisfactory radiographs. The experiments carried out included studying germination and root and shoot growth of seeds planted at different depths, with different orientations and with simulated surface crusts. Seed swelling, root length and rate of shoot growth were measured and with the surface crust qualitative information was observed. Seed orientation and surface crusts (wax layers) delayed penetration of the surface but no effect was noticed on germination. Shoot growth rates were constant no matter what depth the seed was planted, to depths of approximately 80 mm, a maximum depth below which many agricultural crops are not planted. Other experiments are considered and also other potential sources of slow neutrons mentioned. (author)

  18. Neutron radiography: a technique for studying young roots growing in soil

    International Nuclear Information System (INIS)

    The indirect technique for taking neutron radiographs using Indium collector foils has been used to study root growth into soils. The work was done at Ames Laboratory Research Reactor, Iowa, USA, where a neutron beam of 107 n cm-2s-1 was available and 5 x 109 n cm-1 were needed to obtain satisfactory radiographs. The experiments carried out included studying germination and root and shoot growth of seeds planted at different depths, with different orientations, and with simulated surface crusts. Seed swelling, root length, and rate of shoot growth were measured and with the surface crust qualitative information was observed. Seed orientation and surface crusts (wax layers) delayed penetration of the surface but no effect was noticed on germination. Shoot growth rates were constant no matter what depth the seed was planted, to depths of approximately 80 mm, a maximum depth below which many agricultural crops are not planted. Other experiments are considered and also other potential sources of slow neutrons mentioned

  19. A comparison of pixe and neutron activation techniques for thorium and uranium ore analysis

    International Nuclear Information System (INIS)

    Proton induced X-ray emission (PIXE) and neutron activation analysis (NAA) techniques are used to estimate the concentrations of trace quantitites of thorium and uranium in powdered rock or ore samples. The accuracy of the two methods is compared in both a carbon matrix and a variety of ore matrices over the concentration range 1 to 10000 microgram per gram. Under the test conditions the PIXE and NAA concentration estimates for any individual sample in this range are found to be the same within a 3 sigma standard error of 9 per cent

  20. Studies of Some Parameters Affecting The Efficiency and Accuracy of The Neutron Activation Analysis Technique

    International Nuclear Information System (INIS)

    The present studies deal with the optimum physical conditions which seriously affect the neutron activation analysis technique efficiency. An experimental work for the efficiency calibration of hyper pure germanium detectors especially for environmental studies is presented. This work showed that the tested parameters, under consideration, distance, mass and measured time, reveal a significant effect on the obtained data. These results, intern, affect the accuracy of the measurements. Further work on the test of other parameters is planned in our laboratory using special treatments and applying special computer programs

  1. Elemental investigation of talcum baby powder by X-Ray florescence and fast neutron activation Techniques

    International Nuclear Information System (INIS)

    Different samples of Egyptian and Hungarian talcum powders were studied, using X-ray florescence (XRF) and Fast Neutron Activation Analysis (FNAA) techniques to ensure the safety of its use. The K (X-rays) and the gamma-rays were measured, using Si(Li) and high-purity germanium (HPGe) spectrometers to detect and determine qualitatively and quantitatively the constituents of the studied samples. The concentrations of the elements (Mg, Si, Al, Fe, Zn, and Ba) were measured and their presence was confirmed by X-ray, lifetime and/or XRF measurements. One of these samples was also studied, using the Environmental Scanning Electron Microscope (ESEM)

  2. Power measurement of the RA-3 reactor using the neutron noise technique and 16N

    International Nuclear Information System (INIS)

    This work describes a measurement method based on the neutron noise technique which is used for determining the relation between the power and the currents of two ionization chambers. These chambers are sensitive to the gamma radiation from the 16N decay produced in the RA-3 reactor core. The power during operation is obtained from the calibration factors by measuring those currents. As this calibration factors depend on the cooler flow that circulates in the reactor core and in the 16N measuring system, an estimator, that is a function of the ratio of this currents, is proposed in order to detect flow changes. (author)

  3. Enhancements and Health-Related Studies of Neutron Activation Analysis Technique

    International Nuclear Information System (INIS)

    The work presented in this thesis covers two major points. One algorithm concerns with establishment of an accurate standardization method with multi-elemental capabilities and low workload suitable for NAA standardization at ETRR-2. The second one deals with constructing and developing an effective nondestructive technique for analysis of liquid samples based on NAA using (very) short-lived radionuclides. To achieve the first goal, attention has been directed toward implementation of the k0-method for calculation of the elements concentrations in the samples. The k0-method of NAA standardization has a considerable success as a method for accurate multi-elemental analysis with comparable low workload. The k0- method is based on the fact that the unknown sample is irradiated with only one standard element as comparator. To access the implementation of this method at ETRR-2, careful and complete characterization of the neutron flux parameters in the irradiation positions as well as the efficiency calibration of the γ-ray spectrometer must be carried out. The required neutron flux parameters are: the ratio of the thermal to epithermal neutron fluxes (f) and the deviation factor (α) of the epithermal neutron flux from the ideal 1/E law. The work presented in Chapter 4 shows the efficiency calibration curve of the γ ray spectrometer system which was obtained using standard radioactive point sources. Moreover, the f and α parameters were determined in some selected irradiation sites using sets of Zr-Au as neutron flux monitors. Due to different locations relative to the reactor core, the available neutron fluxes in the selected irradiation positions differ substantially, so that different irradiation demands can be satisfied. The reference materials coal NIST 1632c and IAEA-Soil 7 were analyzed for data validation and good agreement between the experimental values and the certified values was obtained. The obtained results have revealed that the k0-NAA procedure

  4. Molecular dynamics in bitumen compounds. A combined study by NMR and neutron scattering techniques

    International Nuclear Information System (INIS)

    The comparative studies by the combined NMR and neutron scattering techniques opened new possibilities for the investigations of the molecular structures and molecular dynamics in liquids as well as in solids. One of the first works of this type, reported in the literature was carried out in our Institute on supercooled liquid phenol. Later, the idea was extended to molecular crystals by a joint research project, between IFIN-HH, Bucharest and Max-Planck Institute-MD Heidelberg, using advanced solid-state NMR and stronger neutron fluxes. Here, we report preliminary results of the combined NMR and neutron scattering investigations on bitumen compounds that are micellar structures with important industrial applications. The goal of the study is to bring information about the molecular dynamics in various phases of these compounds and on this basis to test and/or improve their microscopic models.The neutron scattering measurements were carried out at IBR-2 high flux reactor at JNIR-Dubna. The neutron energy in the incident beam was 4.43 meV and scattering angles ranging from 6 angle to 134 angle. The scattered neutron spectra at room temperature are shown, for several angles. The quasielastic peak gives direct information about the molecular dynamics via the linewidth dependence on the transfer momentum k2. On this basis we calculated an overall diffusion constant Dn = 1.26·10-7 cm2/s. Dn is a superposition of contributions from the various rotational diffusions as well as the Translational diffusion. The neutron scattering data can hardly distinguish between them. This ambiguity can be partially removed by the information brought in by NMR. The temperature dependence of the NMR spin-lattice relaxation time T1 of ESSO-bitumen, measured at ω0/2φ = 25 MHz indicates several particular features: a) The relaxation process cannot be explained by a single relaxation mechanism. The superposition of two V-type mechanisms produces a reasonable agreement with experimental

  5. Epiphytic lichens as quantitative biomonitors for atmospheric element deposition

    International Nuclear Information System (INIS)

    Epiphytic lichens are being used as passive and active biomonitors of trace elements in Slovenia. The lichen Hypogymnia physodes (L.) Nyl. was exposed at three locations (two in the vicinity of a coal fired-power plant, and one at a reference location) for 8 months. At the same locations air particulate matter and total deposition were collected on a monthly basis. The k0-method of neutron activation analysis, using the TRIGA Mark II reactor at the 'Jozef Stefan' Institute, was employed for multielemental nondestructive analysis of all samples. The influence of the power plant on the concentration levels of some elements in the transplanted lichens, air particulates and total deposition is discussed and their correlation presented. (author)

  6. Study of air pollution in Chile using biomonitors

    International Nuclear Information System (INIS)

    A project has been undertaken within the framework of a Co-ordinated Research Programme (CRP) supported by the International Atomic Energy Agency (IAEA) to carry out a long term study on atmospheric air pollution in Chile using biomonitors. The present paper describes the activities undertaken within the framework of this project. Sampling of different lichens species has been performed in clean areas (native forest), preparation of such samples has been done under controlled, cryogenic conditions and analysed by neutron activation analysis. Participation in an intercomparison run organized by the IAEA for the determination of trace and minor elements in two lichens samples, has also been carried out. Transplant of lichens collected in clean areas has been done in Santiago. (author)

  7. Analysis by neutron activation in moss samples for the determination of Cr, Se, As and Hg

    International Nuclear Information System (INIS)

    This research work, presents a study of environmental monitoring in the Metropolitan Area of Toluca Valley using as bio-monitors to the mosses (bryophytes) native of different sites, analyzing the concentrations of As, Cr, Hg and Se, present in its structure. The analysis technique used to identify and to quantify to these elements was the Analysis by Neutron Activation, a nuclear analytic technique that allowed determining the concentrations at track level for its great versatility. Likewise the morphological study of the bryophyte Leskea angustata is presented by scanning electron microscopy. (Author)

  8. Application of pulsed neutron technique for integral neutron cross-section tests in the MeV range

    International Nuclear Information System (INIS)

    The spectra of neutrons scattered by several elements and compounds for an incident beam of 14 MeV neutrons have been studied by the time of flight method at Livermore in the so called 'Livermore Pulsed Sphere Program'. The measurements have been compared with results of Monte Carlo and neutron transport codes to provide checks on the input cross-sections. Similar measurements have been carried out at Oak ridge for incident neutron energies between 1 MeV to 20 MeV with a view to obtain information useful for neutron shielding calculations. The salient features of these measurements and proposals for an experimental program for obtaining data of interest are reviewed. (author)

  9. The soil moisture and its relevance to the landmine detection by neutron backscattering technique

    Energy Technology Data Exchange (ETDEWEB)

    Obhodas, Jasmina; Sudac, Davorin; Nad, Karlo; Valkovic, Vlado E-mail: valkovic@rudjer.irb.hr; Nebbia, Giancarlo; Viesti, Giuseppe

    2004-01-01

    The detection of landmines by using available technologies is a time consuming, expensive and extremely dangerous job, so that there is a need for a technological breakthrough in this field. Atomic and nuclear physics based sensors might offer new possibilities in de-mining. Among the available nuclear techniques, the neutron backscattering technique (NBT), based on the detection of the produced thermal neutrons, is thought to be the most promising for field applications. We discuss here two limitations of NBT, being related to the soil moisture. First, the critical value of the soil moisture, reached when the density of the hydrogen atoms in the landmine is equal to that in the background soil, defines a condition for which the detection is not possible. Critical values are small for some of the landmine types, thus suggesting the application of the method to arid countries, where the soil moisture is lower than 10%. Furthermore, small-scale variations of the soil moisture content, experimentally determined for different soil types, are found to be capable of generating false positive readings. To avoid this problem, the integration of the NBT with a second sensor, as the metal detector, is proposed.

  10. Multi-element study of Rutile sands using the Non Destructive Technique of Neutron Activation Analysis

    International Nuclear Information System (INIS)

    The objective of the method is to analyze qualitative and quantitative elements Ti, Al, Cr, Fe, and Zr in Rutile sands. By this analytical technique, the sample does not require a previous preparation and is then irradiated with a thermal neutron flux in the TRIGA-1 Salazar Reactor. The sample is then counted in a gamma spectrometer fitted with a High-purity detector which make possible the simultaneous determination of the elements in the qualitative and quantitative forms. The elements analyzed in Rutile sands were Ti, Mn, Al, Hf, Dy, Au, W, La, Eu, Ca, Cr, Sc, No and Fe. Nuclear Activation Analysis is a wide used technique for the analysis of trace elements in pure materials or with several major elements. (Author)

  11. Communicating Results in Post-Belmont Era Biomonitoring Studies: Lessons from Genetics and Neuroimaging Research

    Science.gov (United States)

    Morello-Frosch, Rachel; Varshavsky, Julia; Liboiron, Max; Brown, Phil; Brody, Julia G.

    2014-01-01

    Background Biomonitoring is a critical tool to assess the effects of chemicals on health, as scientists seek to better characterize life-course exposures from diverse environments. This trend, coupled with increased institutional support for community-engaged environmental health research, challenge established ethical norms related to biomonitoring results communication and data sharing between scientists, study participants, and their wider communities. Methods Through a literature review, participant observation at workshops, and interviews, we examine ethical tensions related to reporting individual data from chemical biomonitoring studies by drawing relevant lessons from the genetics and neuroimaging fields. Results In all three fields ethical debates about whether/how to report-back results to study participants are precipitated by two trends. First, changes in analytical methods have made more data accessible to stakeholders. For biomonitoring, improved techniques enable detection of more chemicals at lower levels, and diverse groups of scientists and health advocates now conduct exposure studies. Similarly, innovations in genetics have catalyzed large-scale projects and broadened the scope of who has access to genetic information. Second, increasing public interest in personal medical information has compelled imaging researchers to address demands by participants to know their personal data, despite uncertainties about their clinical significance. Four ethical arenas relevant to biomonitoring results communication emerged from our review: Tensions between participants’ right-to-know their personal results versus their ability or right-to-act to protect their health; whether and how to report incidental findings; informed consent in biobanking; and open-access data sharing. Conclusion Ethically engaging participants in biomonitoring studies requires consideration of several issues, including scientific uncertainty about health implications and exposure

  12. Improved Techniques for Low-Flux Measurement of Prompt Neutron Lifetime, Conversion Ratio and Fast Spectra

    International Nuclear Information System (INIS)

    Various statistical methods for the measurement of the ratio of prompt neutron lifetime to delayed fraction have been used in the zero-power reactor programme. One method was originated here, i.e. analysis of reactor noise with a bandpass filter, and others such as the measurement of the frequency of delayed coincidences among counter pulses as a function of delay time and the measurement of the relative variance of time integrals of the neutron flux as a function of integrating time have been refined. The areas of most advantageous application of the various methods have been studied. Attention has also been given to the interpretation of the results of these measurements, and it has been shown that interpretation based on a simple kinetics model is applicable to a wide range of practical cases. Several improvements in our original activation method for the low flux determination of the ratio of production to destruction of fissile material are described. These include the application of very sensitive radiochemical techniques as a confirming procedure; correction for extraneous counts, utilizing foils of different enrichments for the contribution of fission of the fertile material to the fission- product activity and foils exposed to different spectra for fission-related counts in the capture determination; and the use of coincidence counting for the detection of Np239 decay. Obtaining a value for conversion ratio from the activation data requires a knowledge of the ratio of captures to fissions in the fuel, α. No accurate experimental method now exists for the measurement of this quantity in a low flux reactor, but several methods which might make feasible such a determination are being explored. Three of the more promising techniques are outlined. Efforts to develop a small fast neutron spectrometer of good stability, resolution and sensitivity for in-pile measurements of neutron spectra in the energy region of tens and hundreds of kilovolts have been

  13. Non-destructive assay of fissile materials through active neutron interrogation technique using pulsed neutron (plasma focus) device

    International Nuclear Information System (INIS)

    Pulsed neutrons emitted from a plasma focus (PF) device have been used for the first time for the non-destructive assay of 235U content in different chemical forms (oxide and metal). The PF device generates (1.2±0.3)×109 D–D fusion neutrons per shot with a pulse width of 46±5 ns. The method involves the measurement of delayed neutrons from an irradiated sample 50 ms after exposure to the neutron pulse for a time of about 100 s in the multichannel scaling (MCS) mode. The calibration of the active interrogation delayed neutron counter (AIDNEC) system was carried out by irradiating U3O8 samples of varying amounts (0.1–40 g) containing enriched 235U (14.8%) in the device. The delayed neutrons were monitored using a bank of six 3He detectors. The sensitivity of the system was found to be about 100 counts/s/g over the accumulation time of 25 s per neutron pulse of ∼109. The detection limit of the system is estimated to be 18 mg of 235U. The system can be suitably modified for applications toward non-destructive assay of fissile content in waste packets. -- Highlights: ► Plasma focus device has been used for the first time for non-destructive assay of 235U. ► Delayed neutron counting in the multichannel scaling mode is used for the determination of 235U. ► The total time taken for the measurement is about 100 s. ► The detection limit of the system is estimated to be 18 mg of 235U

  14. Non-destructive assay of fissile materials through active neutron interrogation technique using pulsed neutron (plasma focus) device

    Energy Technology Data Exchange (ETDEWEB)

    Tomar, B.S., E-mail: bstomar@barc.gov.in [Radiochemistry and Isotope Group, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kaushik, T.C.; Andola, Sanjay; Ramniranjan,; Rout, R.K. [Multidisciplinary Research Group, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kumar, Ashwani; Paranjape, D.B.; Kumar, Pradeep; Ramakumar, K.L. [Radiochemistry and Isotope Group, Bhabha Atomic Research Centre, Mumbai 400085 (India); Gupta, S.C.; Sinha, R.K. [Multidisciplinary Research Group, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2013-03-01

    Pulsed neutrons emitted from a plasma focus (PF) device have been used for the first time for the non-destructive assay of {sup 235}U content in different chemical forms (oxide and metal). The PF device generates (1.2±0.3)×10{sup 9} D–D fusion neutrons per shot with a pulse width of 46±5 ns. The method involves the measurement of delayed neutrons from an irradiated sample 50 ms after exposure to the neutron pulse for a time of about 100 s in the multichannel scaling (MCS) mode. The calibration of the active interrogation delayed neutron counter (AIDNEC) system was carried out by irradiating U{sub 3}O{sub 8} samples of varying amounts (0.1–40 g) containing enriched {sup 235}U (14.8%) in the device. The delayed neutrons were monitored using a bank of six {sup 3}He detectors. The sensitivity of the system was found to be about 100 counts/s/g over the accumulation time of 25 s per neutron pulse of ∼10{sup 9}. The detection limit of the system is estimated to be 18 mg of {sup 235}U. The system can be suitably modified for applications toward non-destructive assay of fissile content in waste packets. -- Highlights: ► Plasma focus device has been used for the first time for non-destructive assay of {sup 235}U. ► Delayed neutron counting in the multichannel scaling mode is used for the determination of {sup 235}U. ► The total time taken for the measurement is about 100 s. ► The detection limit of the system is estimated to be 18 mg of {sup 235}U.

  15. Multi-technique characterization of neutron fields from moderated 252Cf and 238PuBe sources

    International Nuclear Information System (INIS)

    At the Lawrence Livermore Laboratory, 252Cf and 238PuBe neutron sources are used for calibration of personnel neutron dose meters and neutron monitoring instrumentation. The sources with emission rates of approximately 2x109 and 2x107 n.s-1, respectively, have been calibrated by the United States National Bureau of Standards. The sources are transferred into a 815 m3 concrete calibration cell through a remotely operated pneumatic system. Calibrations can be made without source moderation, or with spherical moderators of aluminium, polyethylene, water or deuterium oxide placed over the end of the pneumatic irradiation tube. The source is located in the tube at one metre above a false floor in the centre of the cell. Nine different moderators are available in sizes up to 56 cm in diameter. Several techniques have been used to characterize the neutron fields produced by each source-moderator configuration to improve the quality of our calibrations. Measurements and calculations have been made to determine neutron flux, kerma rate, neutron spectrum, quality factor, dose equivalent rate and linear energy transfer (LET) spectrum. Neutron spectra are determined by: (1) Calibration using the ANISN discrete ordinates transport code, (2) Bonner sphere measurements using the LOUHI unfolding code, and (3) measurement with proton recoil counters and liquid scintillation detectors. The spectra are then folded into published energy dependent conversion factors to yield kerma, quality factor and dose equivalent values. We obtain LET spectra using a tissue-equivalent LET chamber and the GANDALF unfolding code. Chamber data are used to determine kerma and quality factor. Finally, an 80 cm3 tissue-equivalent ion chamber and neutron-insensitive Geiger counter are used to measure the neutron kerma. Results of the various techniques are presented and compared. In addition, comparisons are made with results obtained from conventional health physics instrumentation such as moderated rem

  16. The Measurement of Reactivity In Multiregion Subcritical Systems by the Pulsed Neutron Technique

    International Nuclear Information System (INIS)

    The prompt decay of a thermalized burst of neutrons in a multiregion subcritical system is examined using a two-group diffusion theory. It is shown that a relationship can be established between the prompt decay constant of the fundamental mode and the effective multiplication factor of the system in terms of two parameters, defined, for the purposes of this paper, as the reactor response coefficient and the prompt decay correction and which depend to a large extent on the spatial flux patterns within the system. For the uniform bare system, the response coefficient can be identified with the mean neutron lifetime in the system; for a multiregion system it represents a compound of the lifetimes in each region weighted by perturbation type integrals. The second parameter, the decay correction, can have no physical meaning in that it arises from an attempt to relate the two scales of reactivity involved; that is the scale using the prompt decay constant and the scale derived using the effective multiplication factor. The properties of these parameters are examined here with reference to an enriched uranium graphitemoderated reactor consisting of uniform core and reflector and it is shown that the two parameters are not uniquely defined by the reactivity of the system but depend on the method chosen to make the system subcritical. Two sets of measurements are treated by the theory. In one, the Windscale Advanced Gas-Cooled Reactor was shut down by a uniform poison. In the other the reactivity of a core in the zero-energy reactor HERO was varied by altering the loaded radius. The neutron pulse measurements are all shown to be in good agreement with more conventional methods of reactivity determination. Some discussion of the experimental techniques and the difficulties encountered in the graphite-moderated systems is presented. (author)

  17. Application of magnetomechanical hysteresis modeling to magnetic techniques for monitoring neutron embrittlement and biaxial stress

    International Nuclear Information System (INIS)

    The objective is to investigate experimentally and theoretically the effects of neutron embrittlement and biaxial stress on magnetic properties in steels, using various magnetic measurement techniques. Interaction between experiment and modeling should suggest efficient magnetic measurement procedures for determining neutron embrittlement biaxial stress. This should ultimately assist in safety monitoring of nuclear power plants and of gas and oil pipelines. In the first six months of this first year study, magnetic measurements were made on steel surveillance specimens from the Indian Point 2 and D.C. Cook 2 reactors. The specimens previously had been characterized by Charpy tests after specified neutron fluences. Measurements now included: (1) hysteresis loop measurement of coercive force, permeability and remanence, (2) Barkhausen noise amplitude; and (3) higher order nonlinear harmonic analysis of a 1 Hz magnetic excitation. Very good correlation of magnetic parameters with fluence and embrittlement was found for specimens from the Indian Point 2 reactor. The D.C. Cook 2 specimens, however showed poor correlation. Possible contributing factors to this are: (1) metallurgical differences between D.C. Cook 2 and Indian Point 2 specimens; (2) statistical variations in embrittlement parameters for individual samples away from the stated men values; and (3) conversion of the D.C. Cook 2 reactor to a low leakage core configuration in the middle of the period of surveillance. Modeling using a magnetomechanical hysteresis model has begun. The modeling will first focus on why Barkhausen noise and nonlinear harmonic amplitudes appear to be better indicators of embrittlement than the hysteresis loop parameters

  18. Development of a novel neutron detection technique by using a boron layer coating a Charge Coupled Device

    CERN Document Server

    Blostein, Juan Jerónimo; Tartaglione, Aureliano; Haro, Miguel Sofo; Moroni, Guillermo Fernández; Cancelo, Gustavo

    2014-01-01

    This article describes the design features and the first test measurements obtained during the installation of a novel high resolution 2D neutron detection technique. The technique proposed in this work consists of a boron layer (enriched in ${^{10}}$B) placed on a scientific Charge Coupled Device (CCD). After the nuclear reaction ${^{10}}$B(n,$\\alpha$)${^{7}}$Li, the CCD detects the emitted charge particles thus obtaining information on the neutron absorption position. The above mentioned ionizing particles, with energies in the range 0.5-5.5 MeV, produce a plasma effect in the CCD which is recorded as a circular spot. This characteristic circular shape, as well as the relationship observed between the spot diameter and the charge collected, is used for the event recognition, allowing the discrimination of undesirable gamma events. We present the first results recently obtained with this technique, which has the potential to perform neutron tomography investigations with a spatial resolution better than that...

  19. Silica Aerogels' nano structure studied using small angle neutron scattering technique

    International Nuclear Information System (INIS)

    Small angle neutron scattering (SANS) technique has been widely employed in probing the microstructure of amorphous materials in the nanometer range. In aerogels system, the size range of 1 - 100 nm is of particular interest since the structural units, such as the pores and particles, often fall in this range. In a typical scattering experiment, scattered neutron intensity is measured as a function of the scattering angle. Various plots of intensity I(Q) and scattering vector, Q, can provide information about fractal dimensions, and particle and cluster sizes. In this study, SANS facilities, at Nuclear Malaysia and Badan Tenaga Atom Nasional (BATAN), Indonesia were used to analyse particle and cluster size of silica aerogels and titanium containing silica aerogels. Results from NM showed that silica aerogels have surface fractal dimension while titanium containing silica aerogels have mass fractal dimension. On the other hand, results from BATAN showed that both silica aerogels and titanium containing silica aerogels have mass fractal dimension. The particle size for silica aerogels and titanium containing silica aerogels samples obtained by NM were 11.18 ± 0.03 and 9.19 ± 0.06 nm, respectively while the respective values obtained from BATAN measurements were 11.78 ± 0.06 and 10.57 ± 0.07 nm. (author)

  20. A neutron-X-ray, NMR and calorimetric study of glassy Probucol synthesized using containerless techniques

    Science.gov (United States)

    Weber, J. K. R.; Benmore, C. J.; Tailor, A. N.; Tumber, S. K.; Neuefeind, J.; Cherry, B.; Yarger, J. L.; Mou, Q.; Weber, W.; Byrn, S. R.

    2013-10-01

    Acoustic levitation was used to trap 1-3 mm diameter drops of Probucol and other pharmaceutical materials in containerless conditions. Samples were studied in situ using X-ray diffraction and ex situ using neutron diffraction, NMR and DSC techniques. The materials were brought into non-equilibrium states by supersaturating solutions or by supercooling melts. The glass transition and crystallization temperatures of glassy Probucol were 29 ± 1 and 71 ± 1 °C respectively. The glassy form was stable with a shelf life of at least 8 months. A neutron/X-ray difference function of the glass showed that while molecular sub-groups remain rigid, many of the hydrogen correlations observed in the crystal become smeared out in the disordered material. The glass is principally comprised of slightly distorted Form I Probucol molecules with disordered packing rather than large changes in the individual molecular structure. Avoiding surface contact-induced nucleation provided access to highly non-equilibrium phases and enabled synthesis of phase-pure glasses.

  1. Use of higher order signal moments and high speed digital sampling technique for neutron flux measurement

    International Nuclear Information System (INIS)

    The second (conventional variance or Campbell signal) , , , the third , and the modified fourth order - 3*2 etc. central signal moments associated with the amplified (K) and filtered currents [i1, i2, x = K * (i2-2>),] from two electrodes of an ex-core neutron sensitive fission detector have been measured versus the reactor power of the 1 MW TRIGA reactor in Mexico City. Two channels of a high speed (400 kHz) multiplexing data sampler and A/D converter with 12 bit resolution and one megawords buffer memory were used. The data were further retrieved into a PC and estimates for auto- and cross-correlation moments up to the fifth order, coherence (/√), skewness (/(√/)3), excess (/2 - 3) etc. quantities were calculated off-line. A five mode operation of the detector was achieved including the conventional counting rates and currents in agreement with the theory and the authors previous results with analogue techniques. The signals were proportional to the neutron flux and reactor power in some flux ranges. The suppression of background noise is improved and the lower limit of the measurement range is extended as the order of moment is increased, in agreement with the theory. On the other hand the statistical uncertainty is increased. At increasing flux levels it was statistically more difficult to obtain flux estimates based on the higher order (≥3) moments

  2. Development of Techniques for a Precision Neutron EDM Measurement at RCNP

    Science.gov (United States)

    Matsumiya, Ryohei; Masuda, Yasuhiro; Kawasaki, Shinsuke; Jeong, Sun-Chan; Watanabe, Yutaka; Hatanaka, Kichiji; Pierre, Edgard; Shin, Yunchang; Matsuta, Kensaku; Mihara, Mototsugu

    2014-09-01

    A non-zero neutron electric dipole moment (nEDM) breaks the time-reversal symmetry. A precision measurement of the nEDM is expected to be a good probe to search for theories beyond the standard model. We have been developing techniques for a nEDM measurement, using a high intensity ultra-cold neutron (UCN) source developed by the collaboration between KEK and RCNP. We have succeeded to polarize UCNs by a super conducting polarizer, and stored them in a cell. This cell will be installed in static magnetic and electric fields for a nEDM observation by the Ramsey separated-oscillatory-field magnetic resonance method. The homogeneity of the magnetic field is being improved aiming to increase the transverse relaxation time T2. A multilayered magnetic shielding and a compensation coil system was developed to cancel the geomagnetic field. Some materials around the cell which were not completely non-magnetic were replaced. We are developing a 129Xe co-magnetometer for the high precision field monitoring, and a high voltage system including electrodes with minimum UCN losses. In this talk, the present status of these apparatuses will be discussed.

  3. Determining neutron capture cross sections with the Surrogate Reaction Technique: Measuring decay probabilities with STARS

    International Nuclear Information System (INIS)

    Neutron-induced reaction cross sections are sometimes difficult to measure due to target or beam limitations. For two-step reactions proceeding through an equilibrated intermediate state, an alternate 'surrogate reaction' technique [J.D. Cramer and H.C. Britt, Nucl. Sci. Eng. 41, 177 (1970), H.C. Britt and J.B. Wilhelmy, Nucl. Sci. Eng. 72, 222 (1979), W.Younes and H.C. Britt, Phys. Rev. C 67, 024610 (2003)] can be applicable, and is currently undergoing investigation at LLNL. Measured decay probabilities for the intermediate nucleus formed in a light-ion reaction can be combined with optical-model calculations for the formation of the same intermediate nucleus via the neutron-induced reaction. The result is an estimation for overall (n,γ/n/2n) cross sections. As a bench-mark, the reaction 92Zr(α, α'), surrogate for n+91Zr, was studied at the A.W. Wright Nuclear Structure Laboratory at Yale. Particles were detected in the silicon telescope STARS (Silicon Telescope Array for Reaction Studies) and γ-ray energies measured with germanium clover detectors from the YRAST (Yale Rochester Array for SpecTroscopy) ball. The experiment and preliminary observations will be discussed

  4. Flow measurement by pulsed-neutron activation techniques at the PKL facility at Erlangen (Germany)

    International Nuclear Information System (INIS)

    Flow velocities in the downcomer at the PKL facility (in Erlangen, Germany) were measured by the Pulsed-Neutron Activation (PNA) techniques. This was the first time that a fully automated PNA system, incorporating a dedicated computer for on-line data reduction, was used for flow measurements. A prototype of a portable, pulsed, high-output neutron source, developed by the Sandia National Laboratories for the US Nuclear Regulatory Commission, was also successfully demonstrated during this test. The PNA system was the primary flow-measuring device used at the PKL, covering the whole range of velocities of interest. In this test series, the PKL simulated small-break accidents similar to the one that occurred at TMI. The flow velocities in the downcomer were, therefore, very low, ranging between 0.03 and 0.35 m/sec. Two additional flow-measuring methods were used over a smaller range of velocities. Wherever comparison was possible, the PNA-derived velocity values agreed well with the measurements performed by the two more conventional methods

  5. Morus nigra plant leaves as biomonitor for elemental air pollution monitoring

    International Nuclear Information System (INIS)

    This study deals with the determination of 36 elements in 120 leaf samples of Morus nigra plant to assess their potential as biomonitor for elemental air pollution monitoring. The elemental quantification was made by employing instrumental neutron activation analysis and atomic absorption spectrometric techniques. The leaf samples were collected in spring, summer and winter seasons from various sites in Islamabad. The reliability of the adopted procedures was established by analyzing the certified reference materials. The calculated enrichment values for all the measured elements in the Morus nigra leave samples during the spring season were minimum as compared to the summer season which in turn were lower than those for the winter season. This gradual increase in enrichment values from spring to winter season can be explained on the basis of extended exposure of leaves to the atmosphere, thus accumulating more metals from the atmosphere leading to higher enrichment values. The lower pollution load index (PLI) values in the spring season could be attributed to less exposure of newly born plant leaves. Higher PLI during summer could probably be due to a series of routine dust storms, resulting in higher concentration of suspended particulate matter. The maximum PLI obtained in the winter season could be related to dry stagnant climatic conditions, having significantly higher concentration of suspended particulate matter, leading to higher accumulation of metals in the plant leaves. The higher metal contents in the leaves of Morus nigra plant as compared to the stem indicate that the absorption of metals from the environment occurs through the leaves. Similar observations have been reported for lead absorption by specific parts of the plants. The results indicated that the adaptation of such reliable and inexpensive procedure using Morus nigra leaves as biomonitor will find a good substitute to the classical approach of collecting aerosol sample with air filter for

  6. Co-ordinated research project on validation and application of plants as biomonitors of trace element atmospheric pollution, analysed by nuclear and related techniques. Report on the 1. research co-ordination meeting

    International Nuclear Information System (INIS)

    Environmental pollution is a cause of ever increasing concern in the world. The UN Conference on Environment and Development (Rio, Brazil, 1992) reaffirmed the importance of protecting the environment within the context of sustainable development. Arising out of this conference, the Rio Agenda 21 declaration called for a number of nationally determined action programmes, with international assistance and co-ordination under 'Capacity 21', concerning environmental monitoring and assessment, including the use of biological markers. Environmental protection and control is a matter of high priority in all developing countries' governmental policies in view of its implications for the welfare of the present and future populations. Therefore it is expected that regional and national organisations responsible for legislation and environmental policy, municipal organisations, which could use the data collected for establishing emission levels, organisations responsible for pollutant emission control and public health-related institutions will benefit from this proposed Co-ordinated Research Project (CRP). The CRP is expected to exploit possibilities of developing and validating tools for using appropriate biomonitors to map the distribution of air pollution over wide areas in developing countries. If successful, this would be a powerful way for developing countries to monitor air pollution

  7. Total neutron cross-sections for rare isotopes using a digital-signal-processing technique: Case study {sup 48}Ca

    Energy Technology Data Exchange (ETDEWEB)

    Shane, R. [Department of Physics, Washington University, Campus Box 1134, St. Louis, MO 63130 (United States); Charity, R.J.; Elson, J.M. [Department of Chemistry, Washington University, Campus Box 1134, St. Louis, MO 63130 (United States); Sobotka, L.G., E-mail: lgs@wustl.ed [Department of Physics, Washington University, Campus Box 1134, St. Louis, MO 63130 (United States); Department of Chemistry, Washington University, Campus Box 1134, St. Louis, MO 63130 (United States); Devlin, M.; Fotiades, N.; O' Donnell, J.M. [LANSCE Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2010-03-11

    A digital-signal-processing method was developed and used to measure the total neutron cross-sections of {sup 48}Ca from 15 to 300 MeV. This technique allows for cross-sections to be obtained with high statistical accuracy even for samples that are an order of magnitude smaller than those used with conventional (non-digital) techniques. The isotopic and energy dependence of rare-isotope total neutron cross-sections are of considerable value for extracting the n/p asymmetry dependence of optical-model potentials.

  8. Studies on the crystalline acetylene-d2 by thermal neutron powder diffraction technique

    International Nuclear Information System (INIS)

    The two crystalline phases of acetylene-d2, C2D2, have been investigated by thermal neutron powder diffraction technique. The crystal structure studies of the orthorhombic low phase at 4.2 K, 77 K and 109 K and of the cubic structure at 150.5 K, as well as investigations on molecular motion and lattice parameter dependence on temperature in the orthorhombic phase along with a report concerning with the orthorhombic-cubic solid phase transition have been published ealier. In the thesis, the reported studies are presented under a main title. A short description of the experimental details is given, and the results and discrepancies of the studies are discussed. (author)

  9. Neutron activation analysis technique for the investigation of environmental contamination with 129I

    International Nuclear Information System (INIS)

    A neutron activation technique is described which does not require specialized apparatus or immediate access to irradiation facilities, but is sufficiently sensitive to measure 129I at the levels encountered around the BNFL nuclear fuel reprocessing plant at Sellafield in west Cumbria, UK. The method allows analysis of a wide range of media and is therefore well suited to environmental investigations. One such application is described in which the deposition pattern of 129I in west Cumbria has been measured, and hence the importance of transfer from sea as a route of terrestrial contamination has been assessed. The current program of research is also described briefly. This involves measurement of 129I in a range of media important in the human food chain and aims to elucidate transfer mechanisms. 4 references, 2 figures

  10. Combined Application of X-Ray and Neutron Imaging Techniques to Wood Materials

    Directory of Open Access Journals (Sweden)

    Roberto Triolo

    2010-12-01

    Full Text Available Conservation of Cultural Heritage is extremely important not only from a cultural point of view, but also from a practical one. It is our duty to pass on to future generations the cultural heritage left tous by our ancestors. Wood is one of the most common materials used to generate works of art which are in a state of constant change and/or deterioration. In order to optimize the knowledge of artworks together with their conservation, it is necessary to use the most advanced scientific and technological tools. In the following paper, we will show the results which can be achieved by application of complementary techniques based on the combined use of X-rays and neutrons as structural probes.

  11. Applying bioethical principles to human biomonitoring

    Directory of Open Access Journals (Sweden)

    Harrison Myron

    2008-06-01

    Full Text Available Abstract Bioethical principles are widely used as a normative framework in areas of human research and medical care. In recent years there has been increasing formalization of their use in public health decisions. The "traditional bioethical principles" are applied in this discussion to the important issue human biomonitoring for environmental exposures. They are: (1 Autonomy – Also known as the "respect for humans" principle, people understand their own best interests; (2 Beneficence – "do good" for people; (3 Nonmaleficence – "do no harm"; (4 Justice – fair distribution of benefits and costs (including risks to health across stakeholders. Some of the points made are: (1 There is not a single generic bioethical analysis applicable to the use of human biomonitoring data, each specific use requires a separate deliberation; (2 Using unidentified, population-based biomonitoring information for risk assessment or population surveillance raises fewer bioethical concerns than personally identified biomonitoring information such as employed in health screening; (3 Companies should proactively apply normative bioethical principles when considering the disposition of products and by-products in the environment and humans; (4 There is a need for more engagement by scholars on the bioethical issues raised by the use of biomarkers of exposure; (5 Though our scientific knowledge of biology will continue to increase, there will always be a role for methods or frameworks to resolve substantive disagreements in the meaning of this data that are matters of belief rather than knowledge.

  12. Biomonitoring of Occupational Exposure to Arylonitrile

    Czech Academy of Sciences Publication Activity Database

    Šrám, Radim; Beskid, Olena; Binková, Blanka; Chvátalová, Irena; Rössner st., Pavel; Rössner ml., Pavel

    2001-01-01

    Roč. 37, č. 32 (2001), s. -. ISSN 0893-6692. [EMS. 16.03.2001-21.03.2001, San Diego] Institutional research plan: CEZ:AV0Z5039906 Keywords : biomonitoring * occupational exposure Subject RIV: DN - Health Impact of the Environment Quality

  13. Measurement of inelastic Scattering cross sections for reactor fast neutrons from Yb174 using the time of flight technique

    International Nuclear Information System (INIS)

    One of the horizontal channel of the reactor of 5 MW has been used to measure the inelastic scattering cross section of fast neutrons (neutron energy between 0.4 to 3.5 MeV) scattered from the rare earth isotope Yb174 by using the time of flight (TOF) technique. The excited levels of Yb174 studied were (KeV, Jπ): [889.70(8+)], [1318,30(2-)], [1606.30(3+)] and [1884.60(5-)] as the results of the integral cross - section of inelastically scattered neutron from these individual levels. Using the asymmetry in the neutron detection at forward and backward neutron counter to deduce the direct interaction to the compound nucleus formation during the inelastic scattering reaction. Eight large (NE-213) neutron counters (4 at 0 degree angle and 4 at 180 degree angle) were used with dimension of 100 cm in length and 8.5 cm in diameter viewed by two photomultiplier tubes to detect the scattered neutrons from the target and two Ge (Li) detectors on the perpendicular direction of neutron counters to measure the γ- rays from the decayed levels of the nucleus. From the coincidence between any of the eight neutron counters and any of the two γ- rays detectors, the start signal in the TOF spectra was measured; trigger at the time of γ- rays and stop from the neutron counter. The time resolution of 8.8 ns has been obtained between the eight neutron counters and one of the γ- rays detectors. Data acquisition and system control were recorded event by event by HP-computer via CAMAC system and IBM computer for off - line analysis. The charge comparison method (CCM) was used for the discrimination between neutron and γ- rays, and the optimization of the parameters were done by using Cf252 neutron source. The experimental results were corrected for the attenuation and multiple - scattering in the sample, when the final results compared with the (HFM) theory

  14. Study of the Condensed Matter Dynamics by the Deep Inelastic Neutron Technique

    International Nuclear Information System (INIS)

    In this work we describe the motivations that originated the eVS technique, and we explain why this technique is particularly useful to study the dynamics of nuclei in different systems.We expose the fundamentals of the convolution formalism usually employed for the data treatment of this technique, which is based on the assumption that the energy of the detected neutrons is fixed by the resonant filter. In this thesis it is presented for the first time the exact formalism that describes the experimentally obtained spectra for thin samples, which considers all pairs of initial and final energies compatible with the flight paths, in clear contrast with the mentioned hypothesis of fixed final energy .In the light of the exact formalism, the analysis presented in the this thesis reveals flaws in the convolution formalism employed for the experimental data treatment.This analysis shows that the deficient descriptions of the different peaks observed in the time of flight scale produce errors in the magnitudes usually informed as results of an eVS experiment, i.e.: intensity of isolated peaks, intensities of peaks not totally resolved, effective temperatures and momentum distributions.To expose the basic reason of such deficiencies, an the exact formalism is employed to analyze the final energy distributions responsible of the observed intensities in the different time channels.We conclude that for each time channel, it is not a well-defined energy, but a whole energy distribution the responsible to produce the observed spectrum.We show that such energy distributions are not determined only by the filter's resonance, but depend strongly on the time of flight due to kinematic and dynamic reasons, not taken into account in the usual data treatment.We analyze examples where the use of the convolution approximation leads to erroneous results, and we show them to have a similar behavior than claimed anomalous results published in several papers, which ascribe them to new

  15. Using devitalized moss for active biomonitoring of water pollution.

    Science.gov (United States)

    Debén, S; Fernández, J A; Carballeira, A; Aboal, J R

    2016-03-01

    This paper presents the results of an experiment carried out for the first time in situ to select a treatment to devitalize mosses for use in active biomonitoring of water pollution. Three devitalizing treatments for the aquatic moss Fontinalis antipyretica were tested (i.e. oven-drying at 100 °C, oven-drying with a 50-80-100 °C temperature ramp, and boiling in water), and the effects of these on loss of material during exposure of the transplants and on the accumulation of different heavy metals and metalloids were determined. The suitability of using devitalized samples of the terrestrial moss Sphagnum denticulatum to biomonitor aquatic environments was also tested. The structure of mosses was altered in different ways by the devitalizing treatments. Devitalization by boiling water led to significantly less loss of material (p < 0.01) than the oven-drying treatments. However, devitalization by oven-drying with a temperature ramp yielded more stable results in relation to both loss of material and accumulation of elements. With the aim of standardizing the moss bag technique, the use of F. antipyretica devitalized by oven-drying with a temperature ramp is recommended, rather than other devitalization treatments or use of S. denticulatum. PMID:26803787

  16. Diagnostic Technique of Neutron Doppler Broadening for Indirectly-Driven Implosions

    Institute of Scientific and Technical Information of China (English)

    熊勇; 丁永坤; 郑志坚; 陈铭

    2004-01-01

    The neutron Doppler broadening in inertial confinement fusion has been acquired from the time of flight for the neutron, from which the fuel ion temperature can be derived. An ultrafast-quenched plastic scintillation detector was used to measure the time of flight for the neutron at a low-imploded DT neutron yield (5×107 ~ 1 × l08) in the experiment performed on the Shenguang II laser facility. The typical temperatures of ablating targets for indirect drive were around 2.8 keV and the uncertainties were ± 30 % ~± 40%. The detection efficiency of the detector for DT neutrons was calibrated at a K-400 accelerator. The time response function of the detection system was calibrated by imploded neutrons from a DT-filled capsule, which can be regarded as a δ function pulsed neutron source due to its much narrower pulse width than that of the measured neutron time-of-flight spectrum.

  17. Validation of computational methods for treatment planning of fast-neutron therapy using activation foil techniques

    Energy Technology Data Exchange (ETDEWEB)

    Nigg, D.W.; Wemple, C.A.; Hartwell, J.K.; Harker, Y.D.; Venhuizen, J.R. [Idaho National Engineering and Environmental Lab., Idaho Falls, ID (United States); Risler, R. [Univ. of Washington Medical Center, Seattle, WA (United States)

    1997-12-01

    A closed-form direct method for unfolding neutron spectra from foil activation data is presented. The method is applied to measurements of the free-field neutron spectrum produced by the proton-cyclotron-based fast-neutron radiotherapy facility at the University of Washington (UW) School of Medicine. The results compare favorably with theoretical expectations based on an a-priori calculational model of the target and neutron beamline configuration of the UW facility.

  18. Implementation of neutron diffraction technique at Nuclear Center of National Institute of Nuclear Research for study of materials

    International Nuclear Information System (INIS)

    The Neutron Diffraction technique, it's a helpful tool for the study of materials. The purpose, was to verify that such technique works with the Neutron Diffractometer of National Institute of Nuclear Research. The scope, is to study crystalline materials by the Neutron Diffraction Method, that means it completion with Bragg's Law. There exist a lot of diffraction techniques that depend on the kind of study to do. In this case the study was to measure known samples to have a correlation between parameters such a extinction factor and dislocation density. Known copper deformed samples were measured to observe the extinction effect and it could be observed. We had to calibrate the Neutron Diffractometer, the detection system and to have an optimal movement control of diffractometer devices by mean of a microcomputer. Also, was necessary to control the Reactor TRIGA operation to minimize the neutron flux oscillation. It was not possible the quantification of dislocation density in the samples because the relation signal/background was about one and it gives high inaccuracy. To correct this problem, it's necessary to have a better shielding to minimize the contribution of the background. The conclusion is that the Neutron Diffractometer is in conditions to carry out investigation on the material field, today it can be lattice constants, crystalline phases and measurements of metallic textures. For such studies, it's necessary to have samples with 2 cm3 or higher to increase the relation signal/background. At present, we have the process software to give the interpretation of the Neutron Diffraction process. (Author). 12 refs, 16 figs

  19. Use of neutron based techniques in the control of illicit trafficking of fissile and explosive material

    International Nuclear Information System (INIS)

    A prototype of portable sealed neutron generator has been recently built to deliver 14 MeV neutron beams tagged by a Yap:Ce α-particle detector in order to produce simultaneously multiple neutron beams to irradiate complex samples. Preliminary tests performed at the Institute Ruder Boskovic, Zagreb (Croatia) on the detection of explosives and fissile materials in maritime containers are presented

  20. Diagnosing Implosion Performance at the National Ignition Facility by Means of Advanced Neutron-Spectrometry and Neutron-Imaging Techniques

    International Nuclear Information System (INIS)

    Full text: Proper assembly of capsule mass, as manifested through the evolution of fuel areal density, is essential for achieving hot-spot ignition planned at the National Ignition Facility (NIF). Experimental information about areal density and areal-density asymmetries, hot-spot ion temperature (Ti) and yield (Yn) are therefore critical for understanding the assembly of the fuel. To obtain this information, a suite of neutron Time-of-Flight (nTOF) spectrometers and a Magnetic Recoil Spectrometer (MRS) has been commissioned and extensively used on the NIF for measurements of the neutron spectrum in the energy range from 1.5 to 20 MeV. This range covers all essential details of the neutron spectrum, allowing for the determination of areal density, Yn, and Ti. The spectrometers are fielded at different locations around the implosion for directional measurements of the neutron spectrum, also allowing for determination of areal-density asymmetries and possible kinetic effects. The data obtained from these diagnostics have been essential to the progress of the National Ignition Campaign (NIC), indicating that the implosion performance, characterized by the Experimental Ignition Threshold Factor (ITFx), has improved about two orders of magnitude since the first cryogenic shot taken in September 2010. Areal-density values greater than 1 g/cm2 are now readily achieved. By combining the areal-density data with information about the spatial extent of the high-density region obtained from Neutron Imaging System (NIS), it has been demonstrated that densities above 500 g/cc and pressure-time (Pτ) products in excess of 10 atm s have been achieved, which are according to HYDRA simulations about a factor of three from ignition conditions. (author)

  1. Dosimetry techniques of thermal neutrons and {gamma} radiation in reactor cores; Techniques de dosimetrie des neutrons thermiques et du rayonnement {gamma} dans les piles

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, J.; Draganic, I.; Hering, H. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    Chemical studies under radiation done in the reactor cores require to be followed by dosimetry. When the irradiations are done in the reflector, one can limit to the measure of the {gamma} and the neutron radiation. For the dosimetry of the {gamma} radiation, a dosimeter of ferrous sulfate is convenient until doses of about 10{sup 6} rep. The use of aired oxalic acid solutions permits to reach 10{sup 7} rep. The dosimetry of thermal neutrons has been made with solutions of cobalt sulphate or paper filter impregnated with this salt. The total chemical effect of the {gamma} and of the slow neutrons radiation is obtained with solutions of ferrous sulfate added with lithium sulphate. (M.B.) [French] Les etudes de chimie sous radiation faites dans les piles exigent d'etre suivies par dosimetrie. Lorsque les irradiations sont effectues dans le reflecteur, on peut se limiter a doser le rayonnement {gamma} et les neutrons. Pour la dosimetrie du rayonnement {gamma}, un dosimetre a sulfate ferreux convient jusqu'a des doses d'environ 10{sup 6} rep. L'emploi de solutions aerees d'acide oxalique permet d'atteindre 10{sup 7} rep. La dosimetrie des neutrons thermiques a ete faite avec des solutions de sulfate de cotalt ou du papier filtre impregne de ce sel. L'effet chimique total du rayonnement {gamma} et des neutrons lents est obtenu avec des solutions de sulfate ferreux additionne de sulfate de lithium. (M.B.)

  2. Neutron Radiography

    OpenAIRE

    Reddy, A. R.; Rao, M. V. N.

    2012-01-01

    The field of neutron radiography with special reference to isotopic neutron radiography has been reviewed. Different components viz., sources, collimators, imaging systems are described. Various designs of neutron radiography facilities, their relative merits and demerits , the appropriateness of each design depending on the object to be radiographed, and economics of each technique are also dealt. The applications of neutron radiography are also briefly presented.

  3. Preliminary measurements of the 14 MeV neutron emission from Frascati tokamak plasma by activation techniques

    International Nuclear Information System (INIS)

    The 1.01 MeV triton burnup has been investigated in the FT (Frascati tokamak) plasma by means of the activation technique. The 14 MeV neutrons produced by triton burnup have been measured with the activation reaction Cu63(n,2n)Cu62 which has a threshold of 10.9 MeV. (orig.)

  4. Determination of pulmonary deposition, translocation and clearance using neutron activation techniques

    International Nuclear Information System (INIS)

    Neutron activation provides a sensitive technique to estimate pulmonary deposition, translocation and clearance of inhaled particles. Talc and fly ash were irradiated in an integrated neutron flux of approximately 1016 n/cm2. Radionuclides were induced by (n, γ) reactions on major and minor elements in the dusts. Hamsters received a single nose-only exposure to the dusts. Groups of 4 to 6 animals were then serially sacrificed at intervals up to 4 months postexposure. Lungs, other tissues of interest and excreta were collected for γ-ray analysis. Limit of detection for the isotopes 60Co or 46Sc was approximately 0.1 dpm, facilitating detection of 10-11 quantities of these elements. Analyzing for more than one radionuclide and comparing their ratios in the bulk dust to those in the tissues or excreta indicated whether a radionuclide leached from the dust particle or represented particles in the tissue samples. Six to 8% of the inhaled talc were deposited in the alveoli; its biological half-life in the lung was 7 to 10 days. Alveolar clearance was essentially complete 4 months postexposure. No translocation of talc to liver, kidneys, ovaries of other parts of the body was found. Picogram quantities of 60Co found in the urine probably respresented leached 60Co, absorbed in the gastrointestinal tract. Two to 3% of the inhaled fly ash were initially retained in the respiratory tract. Estimated biological half-lives were 3 and 35 days for airways and alveoli, resp. After 99 days the mean lung burden had decreased to about 10% of its initial value; extrapolation suggests near-complete pulmonary clearance at about 200 days postexposure. (author)

  5. Integrating techniques for neutron dosimetry in Linac 18 MV; Integrando tecnicas para dosimetria de neutrones en un Linac de 18 MV

    Energy Technology Data Exchange (ETDEWEB)

    Ceron R, P. V.; Diaz G, J. A. I.; Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, 11500 Mexico D. F. (Mexico); Paredes G, L. C. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)

    2015-10-15

    In this paper thermoluminescent dosimetry, analytical techniques and Monte Carlo calculations were used to estimate the neutron dose equivalent in a radiotherapy room with a linear electron accelerator of 18 MV. The equivalent dose was measured at isocenter to 1.42 m of target and at the entrance of the labyrinth of the room of a Novalis Tx. The neutron detectors were constructed with pairs of thermoluminescent dosimeters TLD 600 ({sup 6}LiF: Mg, Ti) and TLD 700 ({sup 7}LiF: Mg, Ti) which are placed inside a paraffin sphere of 20 cm in diameter. These measurements enabled the calculation of equivalent dose in the gate and the source term, using the relationships contained in the NCRP-151. Through the models carried out with the code MCNPX the absorbed dose distribution with regard to depth in a paraffin phantom are included and the neutron spectrum produced by the head, taking into account the geometry and component materials. The results are in the order of neutron milli sievert by gray of X-rays (mSv/Gy x) which are in the same order as those found in other reports for different accelerators. (Author)

  6. Non destructive multi elemental analysis using prompt gamma neutron activation analysis techniques: Preliminary results for concrete sample

    International Nuclear Information System (INIS)

    In this study, principle of prompt gamma neutron activation analysis has been used as a technique to determine the elements in the sample. The system consists of collimated isotopic neutron source, Cf-252 with HPGe detector and Multichannel Analysis (MCA). Concrete with size of 10×10×10 cm3 and 15×15×15 cm3 were analysed as sample. When neutrons enter and interact with elements in the concrete, the neutron capture reaction will occur and produce characteristic prompt gamma ray of the elements. The preliminary result of this study demonstrate the major element in the concrete was determined such as Si, Mg, Ca, Al, Fe and H as well as others element, such as Cl by analysis the gamma ray lines respectively. The results obtained were compared with NAA and XRF techniques as a part of reference and validation. The potential and the capability of neutron induced prompt gamma as tool for multi elemental analysis qualitatively to identify the elements present in the concrete sample discussed

  7. Cold neutron prompt gamma activation analysis, a non-destructive technique for hydrogen level assessment in zirconium alloys

    International Nuclear Information System (INIS)

    Highlights: ► Cold Neutron Prompt Gamma Activation Analysis has been performed to detect hydrogen in various Zr alloys. ► CNPGAA is non-destructive and can precisely detect low levels of hydrogen (as low as 5 wt ppm). ► Hydrogen pick-up fraction of ZIRLO samples has been investigated using CNPGAA and Vacuum hot Extraction. ► It is shown that the hydrogen pick-up fraction undergoes significant increase slightly before the weight gain transition. - Abstract: We propose a novel use of a non-destructive technique to quantitatively assess hydrogen concentration in zirconium alloys. The technique, called Cold Neutron Prompt Gamma Activation Analysis (CNPGAA), is based on measuring prompt gamma rays following the absorption of cold neutrons, and comparing the rate of detection of characteristic hydrogen gamma rays to that of gamma rays from matrix atoms. Because the emission is prompt, this method has to be performed in close proximity to a neutron source such as the one at the National Institute of Technology (NIST) Center for Neutron Research. Determination shown here to be simple and accurate, matching the results given by usual destructive techniques such as Vacuum Hot Extraction (VHE), with a precision of ±2 mg kg−1 (or wt ppm). Very low levels of hydrogen (as low as 5 mg kg−1 (wt ppm)) can be detected. Also, it is demonstrated that CNPGAA can be applied sequentially on an individual corrosion coupon during autoclave testing, to measure a gradually increasing hydrogen concentration. Thus, this technique can replace destructive techniques performed on “sister” samples thereby reducing experimental uncertainties.

  8. Neutron activation analysis technique and X-ray fluorescence in bovine liver sample

    International Nuclear Information System (INIS)

    Many analytical techniques have been used in food and diet analysis in order to determine a great number of nutritional elements, ranging from percentage to ng g-1, with high sensitivity and accuracy. Instrumental Neutron activation Analysis (INAA) has been employed to certificate many trace elements in biological reference materials. More recently, the X-Ray Fluorescence (FRX-WD) has been also used to determine some essential elements in food samples. The INAA has been applied in nutrition studies in our laboratory at IPEN since the 80 s. For the development of analytical methodologies the use of the reference materials with the same characteristics of the sample analyzed is essential. Several Brazilian laboratories do not have conditions to use these materials due their high cost.In this paper preliminary results of commercial bovine liver sample analyses obtained by INAA and WD-XRF methods are presented. This sample was prepared to be a Brazilian candidate of reference material for a group of laboratories participating in a research project sponsored by FAPESP. The concentrations of some elements like Cl, K, Na, P, S and trace elements Br, Ca, Co, Cu, Fe, Mg, Mn, Mo, Rb, Se and Zn were determined by INAA and WD-XFR. For validation methodology of both techniques, NIST SRM 1577b Bovine Liver reference material was analyzed and the detection limits were calculated. The concentrations of elements determined by both analytical techniques were compared by using the Student's t-test and for Cl, Cu, Fe, K, Mg, Na, Rn and Zn the results do show no statistical difference for 95% significance level. (author)

  9. A real-time biomonitoring system to detect arsenic toxicity by valve movement in freshwater clam Corbicula fluminea.

    Science.gov (United States)

    Chen, Wei-Yu; Jou, Li-John; Chen, Suz-Hsin; Liao, Chung-Min

    2012-05-01

    Arsenic (As) is the element of greatest ecotoxicological concern in aquatic environments. Effective monitoring and diagnosis of As pollution via a biological early warning system is a great challenge for As-affected regions. The purpose of this study was to synthesize water chemistry-based bioavailability and valve daily rhythm in Corbicula fluminea to design a biomonitoring system for detecting waterborne As. We integrated valve daily rhythm dynamic patterns and water chemistry-based Hill dose-response model to build into a programmatic mechanism of inductance-based valvometry technique for providing a rapid and cost-effective dynamic detection system. A LabVIEW graphic control program in a personal computer was employed to demonstrate completely the functional presentation of the present dynamic system. We verified the simulated dissolved As concentrations based on the valve daily rhythm behavior with published experimental data. Generally, the performance of this proposed biomonitoring system demonstrates fairly good applicability to detect waterborne As concentrations when the field As concentrations are less than 1 mg L(-1). We also revealed that the detection times were dependent on As exposure concentrations. This biomonitoring system could particularly provide real-time transmitted information on the waterborne As activity under various aquatic environments. This parsimonious C. fluminea valve rhythm behavior-based real-time biomonitoring system presents a valuable effort to promote the automated biomonitoring and offers early warnings on potential ecotoxicological risks in regions with elevated As exposure concentrations. PMID:22359017

  10. Human biomonitoring in civil defense; Humanbiomonitoring im Bevoelkerungsschutz

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Michael; Schmiechen, Katharina [Universitaetsmedizin Goettingen (Germany). Arbeits-, Sozial- und Umweltmedizin

    2012-07-01

    The booklet on human biomonitoring (HBM) in civil defense covers the following issues within two sections: (1) general part: definition and importance of human biomonitoring; application in civil defense; practice in a CBRN (chemical, biological, radiation, nuclear) scenario; sampling following a CBRN assignment; HBM for antidote administration; peculiarities of sampling in case of biological agents; microbiological detection procedure; human biomonitoring of radioactive metal isotopes. (2) Special part: substance profiles; list of HBM laboratories; list of poison information centers; questionnaire for exposure assessment in case of dangerous substance accidents; agreement for human biomonitoring examination.

  11. Extended automated separation techniques in destructive neutron activation analysis; application to various biological materials, including human tissues and blood

    International Nuclear Information System (INIS)

    Neutron activation analysis may be performed as a multi-element and low-level technique for many important trace elements in biological materials, provided that post-irradiation chemical separations are applied. This paper describes a chemical separation consisting of automated procedures for destruction, distillation, and anion-chromatography. The system developed enables the determination of 14 trace elements in biological materials, viz. antimony, arsenic, bromine, cadmium, chromium, cobalt, copper, gold, iron, mercury, molybdenum, nickel, selenium, and zinc. The aspects of sample preparation, neutron irradiation, gamma-spectrum evaluation, and blank-value contribution are also discussed

  12. On the determination of fast neutron spectra with activation techniques: its application in a fusion reactor blanket model

    International Nuclear Information System (INIS)

    A suitable method for the determination of neutron spectra in a CTR-blanket model is the activation technique with threshold detectors. Unfolding of the results from the measurements yields information on the neutron spectrum in the energy range of 2.0-14.1 MeV. The SAND II unfolding program is applied; some investigations have been performed to show the influence of different data files, and of errors in cross sections and activity values. Comparisons of experimental results with values calculated by a Monte Carlo program are presented and discussed. (Auth.)

  13. Quasielastic neutron scattering experiment on water using TOFLAR (Time of flight and Larmor precession) technique at SNS

    International Nuclear Information System (INIS)

    We present the results of the first TOFLAR (Time Of Flight and Larmor precession) experiment with a Larmor modulation device positioned after the sample. Using a setup based on the configuration of the SNS-NSE spectrometer (Spallation Neutron Source, USA), we did TOFLAR measurements on water at 5 and 20 degree Celsius, analyzed the spectra, and obtained diffusion coefficient values that are in a reasonable agreement with literature. Thus, our results demonstrate that TOFLAR may become a standard technique to study quasielastic neutron scattering in future. (authors)

  14. Research within the coordinated programme on neutron scattering techniques in applied research

    International Nuclear Information System (INIS)

    This paper reviews developments of neutron scattering studies at Bhabha Atomic Research Centre (BARC) over the past two decades through utilisation of Apsara and Circus reactor facilities. Salient results in neutron crystallography, magnetic diffraction and inelastic neutron scattering will be presented highlighting progressive involvement in more and more complex studies. The growth of non-neutronic activities as a natural outcome of overall necessity and interest of investigators will be indicated. A description of facilities planned at R5 and the nature of studies that are likely to be taken up at R5 will be briefly discussed. (author)

  15. Biomonitoring for Improving Alcohol Consumption Surveys

    OpenAIRE

    Greenfield, Thomas K.; Bond, Jason; Kerr, William C.

    2014-01-01

    To assess alcohol consumption levels in large populations, researchers often rely on self-report measures. However, these approaches are associated with several limitations, particularly underreporting. Use of noninvasive biomonitoring approaches may help validate self-report alcohol consumption measurements and thus improve their accuracy. Two such devices currently are available, the WrisTAS™ and SCRAM™ devices, both of which measure alcohol vapors emitted through the skin after alcohol con...

  16. On the combination of delayed neutron and delayed gamma techniques for fission rate measurement in nuclear fuel

    International Nuclear Information System (INIS)

    Novel techniques to measure newly induced fissions in spent fuel after re-irradiation at low power have been developed and tested at the Proteus zero-power research reactor. The two techniques are based on the detection of high energy gamma-rays emitted by short-lived fission products and delayed neutrons. The two techniques relate the measured signals to the total fission rate, the isotopic composition of the fuel, and nuclear data. They can be combined to derive better estimates on each of these parameters. This has potential for improvement in many areas. Spent fuel characterisation and safeguard applications can benefit from these techniques for non-destructive assay of plutonium content. Another application of choice is the reduction of uncertainties on nuclear data. As a first application of the combination of the delayed neutron and gamma measurement techniques, this paper shows how to reduce the uncertainties on the relative abundances of the longest delayed neutron group for thermal fissions in 235U, 239Pu and fast fissions in 238U. The proposed experiments are easily achievable in zero-power research reactors using fresh UO2 and MOX fuel and do not require fast extraction systems. The relative uncertainties (1σ) on the relative abundances are expected to be reduced from 13% to 4%, 16% to 5%, and 38% to 12% for 235U, 238U and 239Pu, respectively. (authors)

  17. Elemental analysis of water and soil environmental samples in Tabuk area by neutron capture gamma-ray spectroscopy techniques

    International Nuclear Information System (INIS)

    The prompt and delayed gamma-rays due to neutron capture in the nuclei of the constituent elements of three soil samples and one drinking water sample have been measured. The 252Cf and 226Ra/Be isotopic neutron sources are used for neutron irradiation. Also, the hyper pure germanium detection system is used. The soil samples were from Astra, Tadco and El-Gammaz farms, while the water sample was taken from Tabuk city. In case of prompt gamma-ray analysis, a total of 16 elements were identified and the concentration percentage values by weight were calculated for: C, Na, Mg, Al, Si, S, Cl,, Ca, Ti, Cr, Mn, Fe, Co, Zn, Sr ad Pb elements. A comparative study between the results obtained in this work and the results obtained by ICP-MS and EDX-Ray techniques for the same samples is given

  18. A technique to measure the neutron capture cross-sections of krypton isotopes

    International Nuclear Information System (INIS)

    For the measurement of the neutron capture cross-sections of noble gases an experimental technique was developed, where the probe material is irradiated in its liquid phase. To detect the capture gamma-rays a C6D6 liquid scintillator was constructed providing a defined sensitivity for capture events by applying an appropriate weighting function to the spectra. The capture cross-sections of natural Kr and 84Kr were measured relative to Au in the energy region between 5 keV and 240 keV. Values of Maxwellian averaged capture cross-sections at 5 keV <= kT <= 50 keV were derived, as they are needed for a quantitative understanding of the s-process of nucleosynthesis. By normalizing literature values of the isotopic cross-sections with the derived cross sections it was possible to determine the isotopic abundances produced in the s-process as well as the solar abundance of natural Kr. (orig.) 891 HSI/orig. 892 KN

  19. Characterisation of air particulate matter in Klang Valley by neutron activation analysis technique

    International Nuclear Information System (INIS)

    Air particulate matter is known to affect human health, impairs visibility and can cause climate change. Study on air particulate matter in term of particle size and chemical contents is very important to indicate the quality of air in a sampling area. Information on concentration of important constituents in air particles can be used to identify some of emission sources which contribute to the pollution problem. The data collected may also be, used as a basis to design a strategy in order to overcome the air pollution problem in the area. The study involved sampling of air dust at two stations, one in Bangi and the other in Kuala Lumpur using Gent Stack Sampler units. Each sampler capable of collecting air particle sizes smaller than 2.5 micron (PM 2.5) and between 2.5 - O micron on two different filters simultaneously. The filters were measured for their mass, elemental carbon and elemental concentrations using analytical equipment or techniques including reflectometer and Neutron Activation Analysis. The results of analysis on samples collected in 1997-1998 are discussed. (author)

  20. Variance reduction techniques for 14 MeV neutron streaming problem in rectangular annular bent duct

    Energy Technology Data Exchange (ETDEWEB)

    Ueki, Kotaro [Ship Research Inst., Mitaka, Tokyo (Japan)

    1998-03-01

    Monte Carlo method is the powerful technique for solving wide range of radiation transport problems. Its features are that it can solve the Boltzmann`s transport equation almost without approximation, and that the complexity of the systems to be treated rarely becomes a problem. However, the Monte Carlo calculation is always accompanied by statistical errors called variance. In shielding calculation, standard deviation or fractional standard deviation (FSD) is used frequently. The expression of the FSD is shown. Radiation shielding problems are roughly divided into transmission through deep layer and streaming problem. In the streaming problem, the large difference in the weight depending on the history of particles makes the FSD of Monte Carlo calculation worse. The streaming experiment in the 14 MeV neutron rectangular annular bent duct, which is the typical streaming bench mark experiment carried out of the OKTAVIAN of Osaka University, was analyzed by MCNP 4B, and the reduction of variance or FSD was attempted. The experimental system is shown. The analysis model by MCNP 4B, the input data and the results of analysis are reported, and the comparison with the experimental results was examined. (K.I.)

  1. Measurement of power in research reactors using the neutron noise technique

    International Nuclear Information System (INIS)

    A high precision method based on the neutron noise technique in the frequency domain is proposed to measure the stationary power in a research reactor. An expression of the Power Spectral Density (PSD) was obtained using a theoretical modal solution for the detector field of view. The measured PSD data was fitted using the first term of the solution. The principal theoretical hyphotesis verified experimentally was the predominance of both the fission density fluctuation as the correlated source of noise and the fundamental adjoint kinetic eigenfunction in the detectors' field of view. Measurements were made in natural and forced convection in the RA-6 research reactor located at the Bariloche Atomic Center (CAB), Argentina, in different critical arrangements. For practical purposes it was found that the method can be applied between 10 w and 50 Kw and it does not depend on detector locations. The method was used to calibrate other relative methods in order to measure higher power. The measurements agree with the results obtained using a calorimetric method. (Author)

  2. Development and actualization of scientific searching technique by using small size neutron source

    International Nuclear Information System (INIS)

    In today's crime searching, it becomes more and more important to introduce a new scientific technique to make response to more atrocious crimes. As explosives brought large damages once used for a crime, it is much desired to establish a non-destructive inspection method to protect their use preliminarily. As the explosives were composed mainly of light weight elements with smaller atomic numbers such as hydrogen, carbon, nitrogen and so forth, conventional analysis method using X-ray was insufficient in its sensitivity and difficult in tis analysis. Then, this study aimed to develop a non-destructive inspection method of explosives in a container by using neutron prompt gamma-ray analysis (PGA) method. In 1997 fiscal year, some experiments to reduce radiation exposed dose and upgrade safely around radiation apparatus by changing numbers of radiation source and shielding conditions. As a result, it was found that dose equivalent rate was maximum at a face of detector inserting opening, that the rate had a trend to differ between presence and absence of samples in the apparatus, that the ratio around the apparatus reduced extremely to be 1.5 macro Sv/h at the highest position by reducing magnitude of a radiation source from 9.3 m Ci to 308 micro Ci, and so forth. (G.K.)

  3. Residual strain evaluation of friction stir welded aluminium using neutron diffraction techniques

    International Nuclear Information System (INIS)

    Residual strain evaluations have been performed in the aluminium plate due to friction stir weld (FSW) using neutron diffraction techniques. The sample size was 130 x 50 x 6 mm3 and the welding done along the side of 50 mm. There are two pieces of samples were evaluated with variations of feeding rate, namely 13 and 7.3 mm/ s. Welding performed on the both surface of the sample using 18 mm in diameter and 4 mm length and tip diameter of steering tool. Residual strain measurements performed by using DN1 installed at beam tube number 6 of RSG-GAS Serpong. The residual strain measurement had been performed on Transverse and Normal direction using hkl plane of (220) with a scattering angle around 79 degrees. Incident slit and the detector used is 2 x 2 and 2 x 10 mm2, respectively. Residual tensile strains was observed in both samples in the direction. Normal to the largest value is 1200 μm/ m on samples with a feeding speed 13 mm/ s, whereas the sample with a feeding speed of 7.3 mm/ s is 800 μm/ m. Compression residual strain was found in both samples in Transverse direction, with the largest value of 900 and 700 μm/ m with feeding speed 13 mm/ s and 7.3 mm/ s, respectively. (Author)

  4. Verification of threshold activation detection (TAD) technique in prompt fission neutron detection using scintillators containing 19F

    International Nuclear Information System (INIS)

    In the present study ⌀ 5''× 3'' and ⌀ 2''× 2'' EJ-313 liquid fluorocarbon as well as ⌀ 2'' × 3'' BaF2 scintillators were exposed to neutrons from a 252Cf neutron source and a Sodern Genie 16GT deuterium-tritium (D+T) neutron generator. The scintillators responses to β− particles with maximum endpoint energy of 10.4 MeV from the n+19F reactions were studied. Response of a ⌀ 5'' × 3'' BC-408 plastic scintillator was also studied as a reference. The β− particles are the products of interaction of fast neutrons with 19F which is a component of the EJ-313 and BaF2 scintillators. The method of fast neutron detection via fluorine activation is already known as Threshold Activation Detection (TAD) and was proposed for photofission prompt neutron detection from fissionable and Special Nuclear Materials (SNM) in the field of Homeland Security and Border Monitoring. Measurements of the number of counts between 6.0 and 10.5 MeV with a 252Cf source showed that the relative neutron detection efficiency ratio, defined as εBaF2 / εEJ−313−5'', is 32.0% ± 2.3% and 44.6% ± 3.4% for front-on and side-on orientation of the BaF2, respectively. Moreover, the ⌀ 5'' EJ-313 and side-on oriented BaF2 were also exposed to neutrons from the D+T neutron generator, and the relative efficiency εBaF2 / εEJ−313−5'' was estimated to be 39.3%. Measurements of prompt photofission neutrons with the BaF2 detector by means of data acquisition after irradiation (out-of-beam) of nuclear material and between the beam pulses (beam-off) techniques were also conducted on the 9 MeV LINAC of the SAPHIR facility

  5. Verification of threshold activation detection (TAD) technique in prompt fission neutron detection using scintillators containing 19F

    Science.gov (United States)

    Sibczynski, P.; Kownacki, J.; Moszyński, M.; Iwanowska-Hanke, J.; Syntfeld-Każuch, A.; Gójska, A.; Gierlik, M.; Kaźmierczak, Ł.; Jakubowska, E.; Kędzierski, G.; Kujawiński, Ł.; Wojnarowicz, J.; Carrel, F.; Ledieu, M.; Lainé, F.

    2015-09-01

    In the present study ⌀ 5''× 3'' and ⌀ 2''× 2'' EJ-313 liquid fluorocarbon as well as ⌀ 2'' × 3'' BaF2 scintillators were exposed to neutrons from a 252Cf neutron source and a Sodern Genie 16GT deuterium-tritium (D+T) neutron generator. The scintillators responses to β- particles with maximum endpoint energy of 10.4 MeV from the n+19F reactions were studied. Response of a ⌀ 5'' × 3'' BC-408 plastic scintillator was also studied as a reference. The β- particles are the products of interaction of fast neutrons with 19F which is a component of the EJ-313 and BaF2 scintillators. The method of fast neutron detection via fluorine activation is already known as Threshold Activation Detection (TAD) and was proposed for photofission prompt neutron detection from fissionable and Special Nuclear Materials (SNM) in the field of Homeland Security and Border Monitoring. Measurements of the number of counts between 6.0 and 10.5 MeV with a 252Cf source showed that the relative neutron detection efficiency ratio, defined as epsilonBaF2 / epsilonEJ-313-5'', is 32.0% ± 2.3% and 44.6% ± 3.4% for front-on and side-on orientation of the BaF2, respectively. Moreover, the ⌀ 5'' EJ-313 and side-on oriented BaF2 were also exposed to neutrons from the D+T neutron generator, and the relative efficiency epsilonBaF2 / epsilonEJ-313-5'' was estimated to be 39.3%. Measurements of prompt photofission neutrons with the BaF2 detector by means of data acquisition after irradiation (out-of-beam) of nuclear material and between the beam pulses (beam-off) techniques were also conducted on the 9 MeV LINAC of the SAPHIR facility.

  6. Experimental approaches for distribution and behavior of water in PEMFC under flow direction and differential pressure using neutron imaging technique

    International Nuclear Information System (INIS)

    In this investigation, we prepared a 3-parallel serpentine single PEMFC which has an active area of 25 cm2 and a flow channel cross section of 1x1 mm. Distribution and transport of water in an operating PEMFC were observed by varying the flow directions (co-current and counter-current) in each channel and the differential pressures (100, 200, 300 kPa) applied between the anode and cathode channels. This investigation was performed at the neutron imaging facility at the NIST of which the collimation ratio and neutron fluence rate are 600, 7.2x106 n/s/cm2, respectively. Neutron image was continuously recorded by an amorphous silicon flat panel detector every 1 s during the operation of the fuel cell. It has been observed that the differential pressure affects the total amount of water produced while the flow direction affects the spatial distribution of water when the neutron images were analyzed for several different operating conditions. More specifically, the amount of water production in the fuel cell increased as the partial pressure increases at a given current density and the water production was more uniform for the counter current than the co-current case. It is shown that the neutron imaging technique is a powerful tool to visualize the PEMFC. The information on the water distribution and behavior at an operating PEMFC helps improve the efficiency of PEMFC.

  7. Principles and applications of neutron based inspection techniques in counter terrorism

    International Nuclear Information System (INIS)

    Non-intrusive inspection of objects of all sizes, from luggage to shipping containers and from postal parcels to trucks is a vital component of any national security effort from aviation to the control of all land and sea ports of entry.The neutron-based technologies are unique in meeting all key requirements of reliable inspections. They provide accurate, rapid and objective detection of a wide array of threats explosives, chemical agents, nuclear materials and devices, other hazardous materials, drugs, etc. The technologies being currently employed in the field, such as standard x-ray, x-ray based computed tomography, and trace detection (for luggage), and x-ray or γ-ray based radiography (for containers) are inherently deficient for lacking some or all of these key attributes. The neutron-based technologies, on the other hand, possess to various high degrees all the required attributes. They achieve this feat through their penetration and the production and detection of characteristic elemental gamma rays created mainly in two nuclear reactions: (n,γ-) with thermal neutrons and (n,nNγ-) with fast neutrons produced by appropriate accelerators. These nuclear processes are the basis for several inspection technologies such as the TNA (thermal neutron analysis), FNA (fast neutron analysis), PNI (conventional microsecond pulsed neutron inspection combining the previous two), and PFNA (nanosecond pulsed fast neutron analysis). The principles of operation, applications, and advances in inspection systems will be reviewed

  8. Nondestructive determination of plutonium mass in spent fuel: prelliminary modeling results using the passive neutron Albedo reactivity technique

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Louise G [Los Alamos National Laboratory; Tobin, Stephen J [Los Alamos National Laboratory; Schear, Melissa A [Los Alamos National Laboratory; Menlove, Howard O [Los Alamos National Laboratory; Lee, Sang Y [Los Alamos National Laboratory; Swinhoe, Martyn T [Los Alamos National Laboratory

    2009-01-01

    There are a variety of motivations for quantifying plutonium (Pu) in spent fuel assemblies by means of nondestructive assay (NDA) including the following: strengthening the capability of the International Atomic Energy Agency (LAEA) to safeguard nuclear facilities, quantifying shipper/receiver difference, determining the input accountability value at pyrochemical processing facilities, providing quantitative input to burnup credit and final safeguards measurements at a long-term repository. In order to determine Pu mass in spent fuel assemblies, thirteen NDA techniques were identified that provide information about the composition of an assembly. A key motivation of the present research is the realization that none of these techniques, in isolation, is capable of both (1) quantifying the Pu mass of an assembly and (2) detecting the diversion of a significant number of rods. It is therefore anticipated that a combination of techniques will be required. A 5 year effort funded by the Next Generation Safeguards Initiative (NGSI) of the U.S. DOE was recently started in pursuit of these goals. The first two years involves researching all thirteen techniques using Monte Carlo modeling while the final three years involves fabricating hardware and measuring spent fuel. Here, we present the work in two main parts: (1) an overview of this NGSI effort describing the motivations and approach being taken; (2) The preliminary results for one of the NDA techniques - Passive Neutron Albedo Reactivity (PNAR). The PNAR technique functions by using the intrinsic neutron emission of the fuel (primarily from the spontaneous fission of curium) to self-interrogate any fissile material present. Two separate measurements of the spent fuel are made, both with and without cadmium (Cd) present. The ratios of the Singles, Doubles and Triples count rates obtained in each case are analyzed; known as the Cd ratio. The primary differences between the two measurements are the neutron energy spectrum

  9. Nondestructive determination of plutonium mass in spent fuel: preliminary modeling results using the passive neutron Albedo reactivity technique

    International Nuclear Information System (INIS)

    There are a variety of motivations for quantifying plutonium (Pu) in spent fuel assemblies by means of nondestructive assay (NDA) including the following: strengthening the capability of the International Atomic Energy Agency (LAEA) to safeguard nuclear facilities, quantifying shipper/receiver difference, determining the input accountability value at pyrochemical processing facilities, providing quantitative input to burnup credit and final safeguards measurements at a long-term repository. In order to determine Pu mass in spent fuel assemblies, thirteen NDA techniques were identified that provide information about the composition of an assembly. A key motivation of the present research is the realization that none of these techniques, in isolation, is capable of both (1) quantifying the Pu mass of an assembly and (2) detecting the diversion of a significant number of rods. It is therefore anticipated that a combination of techniques will be required. A 5 year effort funded by the Next Generation Safeguards Initiative (NGSI) of the U.S. DOE was recently started in pursuit of these goals. The first two years involves researching all thirteen techniques using Monte Carlo modeling while the final three years involves fabricating hardware and measuring spent fuel. Here, we present the work in two main parts: (1) an overview of this NGSI effort describing the motivations and approach being taken; (2) The preliminary results for one of the NDA techniques - Passive Neutron Albedo Reactivity (PNAR). The PNAR technique functions by using the intrinsic neutron emission of the fuel (primarily from the spontaneous fission of curium) to self-interrogate any fissile material present. Two separate measurements of the spent fuel are made, both with and without cadmium (Cd) present. The ratios of the Singles, Doubles and Triples count rates obtained in each case are analyzed; known as the Cd ratio. The primary differences between the two measurements are the neutron energy spectrum

  10. Intra-urban biomonitoring: Source apportionment using tree barks to identify air pollution sources.

    Science.gov (United States)

    Moreira, Tiana Carla Lopes; de Oliveira, Regiani Carvalho; Amato, Luís Fernando Lourenço; Kang, Choong-Min; Saldiva, Paulo Hilário Nascimento; Saiki, Mitiko

    2016-05-01

    It is of great interest to evaluate if there is a relationship between possible sources and trace elements using biomonitoring techniques. In this study, tree bark samples of 171 trees were collected using a biomonitoring technique in the inner city of São Paulo. The trace elements (Al, Ba, Ca, Cl, Cu, Fe, K, Mg, Mn, Na, P, Rb, S, Sr and Zn) were determined by the energy dispersive X-ray fluorescence (EDXRF) spectrometry. The Principal Component Analysis (PCA) was applied to identify the plausible sources associated with tree bark measurements. The greatest source was vehicle-induced non-tailpipe emissions derived mainly from brakes and tires wear-out and road dust resuspension (characterized with Al, Ba, Cu, Fe, Mn and Zn), which was explained by 27.1% of the variance, followed by cement (14.8%), sea salt (11.6%) and biomass burning (10%), and fossil fuel combustion (9.8%). We also verified that the elements related to vehicular emission showed different concentrations at different sites of the same street, which might be helpful for a new street classification according to the emission source. The spatial distribution maps of element concentrations were obtained to evaluate the different levels of pollution in streets and avenues. Results indicated that biomonitoring techniques using tree bark can be applied to evaluate dispersion of air pollution and provide reliable data for the further epidemiological studies. PMID:26995269

  11. D-D neutron-scatter measurements for a novel explosives-detection technique

    International Nuclear Information System (INIS)

    A series of measurements has been completed that provides a benchmark for Monte Carlo simulations related to an algorithm for explosives detection using active neutron interrogation. The original simulations used in algorithm development, based on land-sea cargo container screening, have been adapted to model active neutron interrogation of smaller targets. These smaller-scale measurements are easily accomplished in a laboratory environment. Benchmarking measurements were completed using a D-D neutron generator, two neutron detectors, as well as a variety of scatter media including the explosives surrogate melamine (C3H6N6). Measurements included 90°, 120°, or 150° neutron scatter geometries and variations in source-detector shielding, target presence, and target identity. Comparisons of measured and simulated neutron fluxes were similar, with correlation coefficients greater than 0.7. The simulated detector responses also matched very closely with the measured photon and neutron pulse height distributions, with correlation coefficients exceeding 0.9. The experiments and simulations also provided insight into potential application of the new method to the problem of explosives detection in small objects such as luggage and small packages.

  12. D-D neutron-scatter measurements for a novel explosives-detection technique

    Energy Technology Data Exchange (ETDEWEB)

    Lehnert, A.L.; Flaska, M. [Department of NERS, U. Michigan, Ann Arbor, MI 48109-2104 (United States); Kearfott, K.J., E-mail: Kearfott@umich.edu [Department of NERS, U. Michigan, Ann Arbor, MI 48109-2104 (United States)

    2012-11-21

    A series of measurements has been completed that provides a benchmark for Monte Carlo simulations related to an algorithm for explosives detection using active neutron interrogation. The original simulations used in algorithm development, based on land-sea cargo container screening, have been adapted to model active neutron interrogation of smaller targets. These smaller-scale measurements are easily accomplished in a laboratory environment. Benchmarking measurements were completed using a D-D neutron generator, two neutron detectors, as well as a variety of scatter media including the explosives surrogate melamine (C{sub 3}H{sub 6}N{sub 6}). Measurements included 90 Degree-Sign , 120 Degree-Sign , or 150 Degree-Sign neutron scatter geometries and variations in source-detector shielding, target presence, and target identity. Comparisons of measured and simulated neutron fluxes were similar, with correlation coefficients greater than 0.7. The simulated detector responses also matched very closely with the measured photon and neutron pulse height distributions, with correlation coefficients exceeding 0.9. The experiments and simulations also provided insight into potential application of the new method to the problem of explosives detection in small objects such as luggage and small packages.

  13. Neutron intensity modulation and time-focusing with integrated Larmor and resonant frequency techniques

    Science.gov (United States)

    Zhao, Jinkui; Hamilton, William A.; Lee, Sung-Woo; Robertson, J. L.; Crow, Lowell; Kang, Yoon W.

    2015-09-01

    The analysis of neutron diffraction experiments often assumes that neutrons are elastically scattered from the sample. However, there is growing evidence that a significant fraction of the detected neutrons is in fact inelastically scattered, especially from soft materials and aqueous samples. Ignoring these inelastic contributions gives rise to inaccurate experimental results. To date, there has been no simple method with broad applicability for inelastic signal separation in neutron diffraction experiments. Here, we present a simple and robust method that we believe could be suited for this purpose. We use two radio frequency resonant spin flippers integrated with a Larmor precession field to modulate the neutron intensity and to encode the inelastic scattering information into the neutron data. All three components contribute to the spin encoding. The Larmor field serves several additional purposes. Its usage facilitates neutron time-focusing, eliminates the need for stringent magnetic shielding, and allows for compact setups. The scheme is robust, simple, and flexible. We believe that, with further improvements, it has the potential of adding inelastic signal discrimination capabilities to many existing diffraction instruments in the future.

  14. Ethical issues related to biomonitoring studies on children

    DEFF Research Database (Denmark)

    Pedersen, Marie; Merlo, Domenico Franco; Knudsen, Lisbeth E.

    2007-01-01

    data respecting data protection including the right to know or not to know. Data protection is important because stakeholders may also ask for insight at various steps during human biomonitoring activities including children. Finally it is generally recommended that aim, methods, and results from...... biomonitoring studies should be communicated and study persons notified for further use of data and samples....

  15. Video micrography of algae photomovement and vectorial method of biomonitoring

    Science.gov (United States)

    Posudin, Yuri I.; Massjuk, N. P.; Lilitskaya, G. G.

    1996-01-01

    The simultaneous recording of several photomovement parameters of algae as test-functions during biomonitoring is proposed. Green alga Dunaliella viridis Teod. was used as the test- object for the estimation of different heavy metals. The quantitative changes of photomovement parameters as a criterion of toxicity were determined by means of the vectorial method of biomonitoring.

  16. Diffuse neutron scattering: a powerful technique in the study of molecular crystals

    International Nuclear Information System (INIS)

    We have shown that neutron diffuse scattering at ISIS can provide high quality 3-dimensional diffuse scattering data, in this case from thermal correlated motion in a single crystal of the organic molecular crystal benzil. The qualities of the neutron allow very high Q to be reached, and show effects due to the excitations in the system which are invisible when using X-rays. While not appropriate for all diffuse scattering problems, we have shown that modern neutron sources are capable of providing detailed diffuse scattering data which, when refined in parallel with the X-ray data, will give unequalled insight into the structure of disordered systems

  17. Amino acids analysis using grouping and parceling of neutrons cross sections techniques

    International Nuclear Information System (INIS)

    Amino acids used in parenteral administration in hospital patients with special importance in nutritional applications were analyzed to compare with the manufactory data. Individual amino acid samples of phenylalanine, cysteine, methionine, tyrosine and threonine were measured with the neutron crystal spectrometer installed at the J-9 irradiation channel of the 1 kW Argonaut Reactor of the Instituto de Engenharia Nuclear (IEN). Gold and D2O high purity samples were used for the experimental system calibration. Neutron cross section values were calculated from chemical composition, conformation and molecular structure analysis of the materials. Literature data were manipulated by parceling and grouping neutron cross sections. (author)

  18. Elemental analysis technique based on detecting gamma-rays from interactions of neutrons with medium

    International Nuclear Information System (INIS)

    The methods are discussed of carbon content determination in large amounts of material by detecting 4438 keV gamma radiation accompanying inelastic scattering of neutrons from a radionuclide neutron source. Presented are the methodological analysis of the problem, the results of test measurements, and methodological recommendations for the practical application of the method. Test measurements were conducted on fly ash, limestone and brown coal in amounts of approximately 5 kg for each material sample, using an Am-Be neutron source. The determined sensitivity thresholds corresponded to the carbon concentration of 5 to 10% w.w. (S.P.)

  19. Neutron dose equivalent rate meter on the basis of the single sphere Albedo technique

    International Nuclear Information System (INIS)

    In area monitoring there is a need for a more accurate neutron reference dose rate meter, especially for the purpose of albedo dosemeter calibrations in neutron stray radiation fields of interest. The so-called Single Sphere Albedo Counter makes use of three active 3He proportional counters as thermal neutron detectors positioned in the centre and on the surface (albedo dosemeter configurations) of a polyethylene sphere. The linear combination of the detector readings allows for the indication of different quantities like H*(10),D,φ, and reduces the energy dependence significantly. The paper describes the dosimetric properties of a prototype instrument and its application in routine monitoring. (author)

  20. Progress of neutron induced prompt gamma analysis technique in 1988~2003

    Institute of Scientific and Technical Information of China (English)

    JING Shi-Wei; LIU Yu-Ren; CHI Yan-Tao; TIAN Yu-Bing; CAO Xi-Zheng; ZHAO Xin-Hui; REN Wan-Bin; LIU Lin-Mao

    2004-01-01

    This paper describes new development of the neutron induced prompt gamma-ray analysis (NIPGA) technology in 1988~2003. The pulse fast-thermal neutron activation analysis method, which utilized the inelastic re action and capture reaction jointly, was employed to measure the elemental contents more efficiently. Lifetime of the neutron generator was more than 10000h and the performance of detector and MCA reached a high level. At the same time, Monte Carlo library least-square method was used to solve the nonlinearity problem in the NIPGA.

  1. New technique to improve the accuracy of albedo neutron dosimeter evaluations

    International Nuclear Information System (INIS)

    The calibration factor for albedo neutron dosimeters varies greatly depending upon the energy of the neutrons in the exposure. Calibration results obtained over an eight-year period at each Lawrence Livermore National Laboratory facility where neutron exposure may occur were reviewed. A stronger relationship than expected was found between the ratio of the readings of the 9-in. to 3-in. spheres and the percent thermal. Readings from personnel and albedo badges were reviewed. The readings were consistent with the use of a calibration factor for the albedo dosimeter which varies with changes in the ratio of the personnel and albedo dosimeter TLD readings. 2 references, 6 figures

  2. Study on uranium-water multiplicative means of the (RESUCO-Subcritical experimental reactor of uranium with oxygen) subcritical assembly by pulsed neutron technique

    International Nuclear Information System (INIS)

    The effective multiplication factor and the nuclear parameters associated with the variation of (RESUCO- Subcritical Experimental Reactor of Uranium with Oxygen) Subcritical Assembly Configuration, using pulsed neutron technique are analysed. BF3 detectors were used to detect the variation of thermal neutrons in the system, positioned parallelly to fuel elements, and a proton recoil detector was used for monitoring the neutron generation. (M.C.K.)

  3. Replika mirrors-Nearly loss-free guides for ultracold neutrons-Measurement technique and first preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Plonka, C. [Institut Laue Langevin, 6 rue Jules Horowitz, 38042 Grenoble (France)]. E-mail: plonka@ill.fr; Geltenbort, P. [Institut Laue Langevin, 6 rue Jules Horowitz, 38042 Grenoble (France); Soldner, T. [Institut Laue Langevin, 6 rue Jules Horowitz, 38042 Grenoble (France); Haese, H. [S-DH GmbH, Hans-Bunte-Strasse 8-10, 69123 Heidelberg (Germany)

    2007-08-01

    The reflectivity of ultracold neutron (UCN) guides produced with a dedicated technique called REPLIKA has been studied. The guides are made of nickel, where the surface quality was copied from a glass layer. This results in a surface roughness smaller than 10 A. The reflectivity was measured to be 99.9 (1)%. Those guides can be used at present or future UCN sources to transport UCN over long distances to the respective experiments without significant losses.

  4. Search for the existence of circulating currents in high-$T_c$ superconductors using the polarized neutron scattering technique

    OpenAIRE

    Sidis, Yvan; Fauqué, Benoit; Aji, Vivek; Bourges, Philippe

    2006-01-01

    We review experimental attempts using polarized neutron scattering technique to reveal the existence in high temperature superconductors of a long-range ordered state characterized by the spontaneous appearance of current loops. We draw a particular attention to our recent results (B. Fauqu\\'e {\\it et al.}, {\\it Phys. Rev. Lett.} {\\bf 96}, 197001 (2006)) that, up to now, can be explained only by the theory of circulating current proposed by C.M. Varma.

  5. Search for the existence of circulating currents in high-T{sub c} superconductors using the polarized neutron scattering technique

    Energy Technology Data Exchange (ETDEWEB)

    Sidis, Y. [Laboratoire Leon Brillouin, CEA-CNRS, CEA-Saclay, 91191 Gif sur Yvette (France)]. E-mail: yvan.sidis@cea.fr; Fauque, B. [Laboratoire Leon Brillouin, CEA-CNRS, CEA-Saclay, 91191 Gif sur Yvette (France); Aji, V. [Department of Physics, University of California, Riverside, CA 92521 (United States); Bourges, P. [Laboratoire Leon Brillouin, CEA-CNRS, CEA-Saclay, 91191 Gif sur Yvette (France)

    2007-07-15

    We review experimental attempts using polarized neutron scattering technique to reveal the existence in high temperature superconductors of a long-range ordered state characterized by the spontaneous appearance of current loops. We draw particular attention to our recent results (B. Fauque et al., Phys. Rev. Lett. 96 (2006) 197001) that, up to now, can be explained only by the theory of circulating currents proposed by Varma.

  6. Prompt gamma neutron activation analysis as an active interrogation technique for nuclear materials

    International Nuclear Information System (INIS)

    Prompt gamma neutron activation analysis (PGAA) is proposed as an instant, non-destructive method for the analysis of fissile materials and fission products. Measurements by PGAA were made on technetium and uranium compounds, the latter with various enrichments. Measurements were carried out in thermal and cold neutron beams at the Budapest Research Reactor. A beam chopper was used to collect the delayed decay gamma radiation from short lived nuclides separately. Accurate partial gamma ray production cross-sections were determined with internal standardization for a set of prompt and decay gamma rays following neutron capture in 235U, 238U and 99Tc and compared to those from the literature. In the case of 235U fission, prompt gamma lines were also applied.These cross-sections can be used for non-destructive analyses of uranium and technetium and also for the determination of the enrichment of uranium by prompt gamma activation analysis and neutron activation analysis. (author)

  7. Application of neutron radiography techniques to the nondestructive testing of pyrotechnical components and space systems

    International Nuclear Information System (INIS)

    Neutron radiography is used at every level of the development of pyrotechnical components and associated systems. Two examples of failure analysis are given in the cases of a pyrotechnical cutting machine and a pyrotechnical cartridge

  8. Study on measurement technique contrast of 14 MeV neutron fluence

    International Nuclear Information System (INIS)

    The stability and repetition of the associated-particle method to measure DT neutron fluence was tested. The neutron activation iron method was contrasted with the associated-particle method, the preparatory experiment was done. The neutron fluence measured with associated-particle method was contrasted with neutron activation Al method, the Al activated foil was measured with 4πβ (PC)-γ coincidence standard device. The contrast result's standard deviation of the two method was less than the expand uncertainty of the associated-particle method. Therein, the uncertainty of the associated-particle method is 1.6%, the uncertainty of the activation Al method is 1.8%. (authors)

  9. Development of a stochastic temperature treatment technique for Monte Carlo neutron tracking

    OpenAIRE

    Viitanen, Tuomas

    2015-01-01

    Thermal motion of nuclides has a significant effect on the reaction probabilities and scattering kinematics of neutrons. Since also the nuclides in nuclear reactor materials are in constant thermal motion, the temperature-induced effects need to be taken into account in all neutron transport calculations. This task is notably complicated by the fact that the temperature distributions within operating power reactors are always non-uniform. With conventional transport methods, accurate model...

  10. Primary Displacement Damage Calculation Induced by Neutron and Ion Using Binary Collision Approximation Techniques (Marlowe Code)

    International Nuclear Information System (INIS)

    The level of damage expected in future fusion reactors conditions is such that the performance of materials and components under these extreme irradiation conditions is still unknown. Considering this scenario, the study of the effects of energetic neutrons generated in fusion reactors on materials is one of the most important research topics to be carried out during next years. The effects of neutron irradiation on materials involve, from a fundamental point of view, two physical phenomena: i) the displacement of atoms from their equilibrium positions in the lattice, which creates point defects, and ii) the generation of nuclear transmutation reactions that contribute to the formation of impurities inside the material, with He and H as the most important ones. The ratio between the levels of He and H, and the amount of point defects is one of the main parameters to understand the effect of the radiation on materials. In order to emulate the neutron irradiation that would prevail under fusion conditions, two approaches are contemplated: a) on one hand different kinds of current neutron sources to emulate the fusion irradiation environment are available, as for example - Fission power reactor - Spallation sources - Striping Sources: The objective of the International Fusion Materials Irradiation Facility (IFMIF) will be to provide an intense neutron source with adequate energy spectrum to test the suitability of candidate materials for future nuclear fusion power reactor (DEMO). IFMIF will constitute an essential tool in the international strategy towards the achievement of future fusion reactors. b) on the other hand, as these neutron sources have a number of problems and very strict operating conditions, (e.g. the radiological risks), to emulate the effects of fusion neutron on materials, some other facilities can be used. One example is the Spanish initiative TechnoFusion facility which purpose is to serve as technological support for IFMIF and DEMO. The Material

  11. Determination of boron in aqueous solutions by solid state nuclear track detectors technique, using a filtered neutron beam

    International Nuclear Information System (INIS)

    The solid state nuclear track detectors technique has been used for determination of boron in aqueous solutions, using a filtered neutron beam. The particles tracks from the 10B(n,α)Li7 reaction were registered in the CR-39 film, chemically etched in a (30%) KOH solution 700C during 90 minutes. The obtained results showed the usefulness of this technique for boron determination in the ppm range. The inferior detectable limit was 9 ppm. The combined track registration efficiency factor K has been evaluated in the solutions, for the CR-39 detector and its values is K= (4,60 -+ 0,06). 10 -4 cm. (Author)

  12. Standard Test Method for Oxygen Content Using a 14-MeV Neutron Activation and Direct-Counting Technique

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This test method covers the measurement of oxygen concentration in almost any matrix by using a 14-MeV neutron activation and direct-counting technique. Essentially, the same system may be used to determine oxygen concentrations ranging from over 50 % to about 10 g/g, or less, depending on the sample size and available 14-MeV neutron fluence rates. Note 1 - The range of analysis may be extended by using higher neutron fluence rates, larger samples, and higher counting efficiency detectors. 1.2 This test method may be used on either solid or liquid samples, provided that they can be made to conform in size, shape, and macroscopic density during irradiation and counting to a standard sample of known oxygen content. Several variants of this method have been described in the technical literature. A monograph is available which provides a comprehensive description of the principles of activation analysis using a neutron generator (1). 1.3 The values stated in either SI or inch-pound units are to be regarded...

  13. Utilizing the slowing-down-time technique for benchmarking neutron thermalization in graphite

    International Nuclear Information System (INIS)

    Graphite is the moderator/reflector in the Very High Temperature Reactor (VHTR) concept of Generation IV reactors. As a thermal reactor, the prediction of the thermal neutron spectrum in the VHTR is directly dependent on the accuracy of the thermal neutron scattering libraries of graphite. In recent years, work has been on-going to benchmark and validate neutron thermalization in 'reactor grade' graphite. Monte Carlo simulations using the MCNP5 code were used to design a pulsed neutron slowing-down-time experiment and to investigate neutron slowing down and thermalization in graphite at temperatures relevant to VHTR operation. The unique aspect of this experiment is its ability to observe the behavior of neutrons throughout an energy range extending from the source energy to energies below 0.1 eV. In its current form, the experiment is designed and implemented at the Oak Ridge Electron Linear Accelerator (ORELA). Consequently, ORELA neutron pulses are injected into a 70 cm x 70 cm x 70 cm graphite pile. A furnace system that surrounds the pile and is capable of heating the graphite to a centerline temperature of 1200 K has been designed and built. A system based on U-235 fission chambers and Li-6 scintillation detectors surrounds the pile. This system is coupled to multichannel scaling instrumentation and is designed for the detection of leakage neutrons as a function of the slowing-down-time (i.e., time after the pulse). To ensure the accuracy of the experiment, careful assessment was performed of the impact of background noise (due to room return neutrons) and pulse-to-pulse overlap on the measurement. Therefore, the entire setup is surrounded by borated polyethylene shields and the experiment is performed using a source pulse frequency of nearly 130 Hz. As the basis for the benchmark, the calculated time dependent reaction rates in the detectors (using the MCNP code and its associated ENDF-B/VI thermal neutron scattering libraries) are compared to measured

  14. Biomonitoring air pollution in Chelyabinsk region (Ural mountains, Russia) through trace-elements and radionuclides: Temporal and spatial trends

    International Nuclear Information System (INIS)

    This report contains the first results on the analysis of the moss species Hylocomium splendens and Pleurozium schreberi which were used to study heavy metal atmospheric deposition in the vicinity of Magnitogorsk, the center of the iron steel industry of Russia. Moss samples were collected along Bannoe Lake, located 30 km north-west of Magnitogorsk, and were analyzed by instrumental neutron activation analysis using epithernal neutrons (ENAA) at the IBR-2 pulsed fast reactor in Dubna, and by atomic absorption spectroscopy (AAS) at the Geological Institute of RAS, Moscow. Results for a total of 38 elements were obtained, including Pb, Cd, and Cu determined by AAS. The element concentrations in moss samples from this area were compared with those available for the so-called 'Black Triangle' (the territory bordering Poland, Czechia and Slovakia), obtained by the same moss biomonitoring technique. The level of the concentrations of Fe, Cr, and V in the vicinity of Magnitogorsk was found to be 2-2.5 times higher than that of the mean values determined for the 'Black Triangle'; the level of Ni and Cd is of the same order as in the most polluted area of Europe. The concentrations of Zn and Cu tend to be higher in the 'Black Triangle'. The level of As is about 3 times higher in the Urals, whereas concentration of Pb is higher in Europe by a factor of 5. It appeared that concentration of Sb in the examined area has the highest ever published for levels in mosses from atmospheric deposition. The scanning electron microscope adjacent to the XRF analyzer (SEM-XRF) was used to examine the surface of the moss samples. Photographs of identified iron spherulas along with other aerosol particles were made at magnification of 3,500 to 5,000 times. Information on fieldwork in the northern part of the Chelyabinsk region in July, 1998 is reported. (author)

  15. Structural studies of nano-structured carbons: complementary x-ray and neutron techniques using short wavelengths

    International Nuclear Information System (INIS)

    Carbon materials have a wide range of structural characteristics that can be studied by diffraction and small-angle scattering techniques using either synchrotron x-rays and/or neutrons. In order to obtain good spatial resolution in the pair correlation functions [g(r)], it is necessary to measure the structure factor [S(Q)] over a wide range of Q-values, requiring the use of short wavelength beams (with λ ∼ 0.1-0.2 A). During recent years, the use of pulsed neutrons from spallation sources such as ISIS (at RAL) and high energy x-ray beams from third generation sources (such as the ESRF) have allowed the development of powerful new methods for studying these materials. This brief review focuses on the properties of various carbon materials using a range of modern diffraction techniques:- Activated carbons made from saccharose and anthracene precursors, showing different ''graphitisng'' features, Diamond nanoparticles (∼ 50 A) convert to carbon onions and facet ted graphitic particles on heat treatment, Carbon nanotubes show detailed in-plane structure of curved graphene sheets in single and multi-walled nanotubes Carbon nanotubes grown in restricted geometry show partial orientation. Carbon nanohorns reveal detailed structural features for opened and unopened nanotubes. For these ''homonuclear'' systems the techniques of reactor neutrons, pulsed neutrons and synchrotron x-rays (normal and high energy) are seen to be complementary. Optimal measurements depend on sample quantity, Q-range and texture (orientational dependence). The review concludes with a speculation on likely future developments. (author)

  16. PREFACE: Exploring surfaces and buried interfaces of functional materials by advanced x-ray and neutron techniques Exploring surfaces and buried interfaces of functional materials by advanced x-ray and neutron techniques

    Science.gov (United States)

    Sakurai, Kenji

    2010-12-01

    This special issue is devoted to describing recent applications of x-ray and neutron scattering techniques to the exploration of surfaces and buried interfaces of various functional materials. Unlike many other surface-sensitive methods, these techniques do not require ultra high vacuum, and therefore, a variety of real and complicated surfaces fall within the scope of analysis. It must be particularly emphasized that the techniques are capable of seeing even buried function interfaces as well as the surface. Furthermore, the information, which ranges from the atomic to mesoscopic scale, is highly quantitative and reproducible. The non-destructive nature of the techniques is another important advantage of using x-rays and neutrons, when compared with other atomic-scale analyses. This ensures that the same specimen can be measured by other techniques. Such features are fairly attractive when exploring multilayered materials with nanostructures (dots, tubes, wires, etc), which are finding applications in electronic, magnetic, optical and other devices. The Japan Applied Physics Society has established a group to develop the research field of studying buried function interfaces with x-rays and neutrons. As the methods can be applied to almost all types of materials, from semiconductor and electronic devices to soft materials, participants have fairly different backgrounds but share a common interest in state-of-the-art x-ray and neutron techniques and sophisticated applications. A series of workshops has been organized almost every year since 2001. Some international interactions have been continued intensively, although the community is part of a Japanese society. This special issue does not report the proceedings of the recent workshop, although all the authors are in some way involved in the activities of the above society. Initially, we intended to collect quite long overview papers, including the authors' latest and most important original results, as well as

  17. Applicability of a Bonner Shere technique for pulsed neutron in 120 GeV proton facility

    Energy Technology Data Exchange (ETDEWEB)

    Sanami, T.; Hagiwara, M.; Iwase, H.; /KEK, Tsukuba; Iwamoto, Y.; Sakamoto, Y.; Nakashima, H.; /JAEA, Ibaraki; Arakawa, H.; Shigyo, N.; /Kyushu U.; Leveling, A.F.; Boehnlein, D.J.; Vaziri, K.; /Fermilab

    2008-02-01

    The data on neutron spectra and intensity behind shielding are important for radiation safety design of high-energy accelerators since neutrons are capable of penetrating thick shielding and activating materials. Corresponding particle transport codes--that involve physics models of neutron and other particle production, transportation, and interaction--have been developed and used world-wide [1-8]. The results of these codes have been ensured through plenty of comparisons with experimental results taken in simple geometries. For neutron generation and transport, several related experiments have been performed to measure neutron spectra, attenuation length and reaction rates behind shielding walls of various thicknesses and materials in energy range up to several hundred of MeV [9-11]. The data have been used to benchmark--and modify if needed--the simulation modes and parameters in the codes, as well as the reference data for radiation safety design. To obtain such kind of data above several hundred of MeV, Japan-Fermi National Accelerator Laboratory (FNAL) collaboration for shielding experiments has been started in 2007, based on suggestion from the specialist meeting of shielding, Shielding Aspects of Target, Irradiation Facilities (SATIF), because of very limited data available in high-energy region (see, for example, [12]). As a part of this shielding experiment, a set of Bonner sphere (BS) was tested at the antiproton production target facility (pbar target station) at FNAL to obtain neutron spectra induced by a 120-GeV proton beam in concrete and iron shielding. Generally, utilization of an active detector around high-energy accelerators requires an improvement on its readout to overcome burst of secondary radiation since the accelerator delivers an intense beam to a target in a short period after relatively long acceleration period. In this paper, we employ BS for a spectrum measurement of neutrons that penetrate the shielding wall of the pbar target

  18. 光学相衬成像技术在中子照相中的应用%Neutron Phase Contrast Imaging teChnique

    Institute of Scientific and Technical Information of China (English)

    吴洋; 唐彬; 霍合勇

    2012-01-01

    介绍了中子相衬成像原理及其特点,对中子相衬成像中的同轴轮廓法进行了重点论述,讨论了相衬成像的条件及实验技术,简介了SPRR-300拟进行的相衬成像技术研究方法.%The principle for neutron phase contrast is this paper. Emphases Discuss In - line neutron imaging principle . The experiment technique and condition of neutron phase contrast imaging are discussed. At last, introduce the research project on SPRR - 300 neutron imaging system.

  19. Fast neutron detection under intense gamma-ray fields with novel nuclear emulsion technique

    International Nuclear Information System (INIS)

    In order to measure neutron flux and energy in the presence of high-intensity background gamma rays, a new nuclear emulsion based on a non-sensitized OPERA film was synthesized, which had small AgBr grain sizes of 60, 90 and 160 nm. The sensitivity of this new emulsion, which is described in terms of the stopping power and grain density, was estimated experimentally by neutron irradiation at several energies. The response of the emulsion to gamma-ray-induced electrons was also simulated and the results were compared with experimental data obtained using a 60Co gamma source. The results indicated that each AgBr grain has a threshold energy that must be deposited before the AgBr can develop into metallic Ag. Based on these results, the efficiency of the new emulsion in detecting gamma rays and neutrons was evaluated. -- Highlights: ► Purpose of our study is measurement of neutron under high intensity gamma-ray. ► We synthesized new nuclear emulsion based on non-sensitized OPERA emulsion. ► We estimated efficiency to gamma-ray and neutron of the new nuclear emulsion

  20. The multianalyser system of the three axes neutron spectrometer PUMA: Pilot experiments with the innovative multiplex technique

    International Nuclear Information System (INIS)

    A new type of multiplex technique for three axes neutron spectrometers has been realized and successfully commissioned at the PUMA spectrometer at FRM II. Consisting of eleven analyser-detector channels which can be configured individually, this technique is especially suitable for kinetic experiments where a single excitation spectrum is recorded as a function of time without the need to move the spectrometer. On a time-scale of seconds an entire spectrum can be recorded thus allowing users to monitor changes during fast kinetic processes in single shot experiments without the need for stroboscopic techniques. Moreover, the multianalyser system provides an efficient and rapid tool for mapping excitations in (Q,ω)-space. The results of pilot experiments demonstrate the performance of this new technique and a user-friendly software is presented which assists users during their experiments

  1. The multianalyser system of the three axes neutron spectrometer PUMA: Pilot experiments with the innovative multiplex technique

    Science.gov (United States)

    Sobolev, Oleg; Hoffmann, Ron; Gibhardt, Holger; Jünke, Norbert; Knorr, Andreas; Meyer, Volker; Eckold, Götz

    2015-02-01

    A new type of multiplex technique for three axes neutron spectrometers has been realized and successfully commissioned at the PUMA spectrometer at FRM II. Consisting of eleven analyser-detector channels which can be configured individually, this technique is especially suitable for kinetic experiments where a single excitation spectrum is recorded as a function of time without the need to move the spectrometer. On a time-scale of seconds an entire spectrum can be recorded thus allowing users to monitor changes during fast kinetic processes in single shot experiments without the need for stroboscopic techniques. Moreover, the multianalyser system provides an efficient and rapid tool for mapping excitations in (Q,ω)-space. The results of pilot experiments demonstrate the performance of this new technique and a user-friendly software is presented which assists users during their experiments.

  2. Vapor fraction measurements in a steam-water tube at up to 15 bar using neutron radiography techniques

    CERN Document Server

    Glickstein, S S; Joo, H

    1999-01-01

    Real-time neutron radiography has been used to study the dynamic behavior of two-phase flow and measure the time averaged vapor fraction in a heated metal tube containing boiling steam-water operating at up to 15 bar pressure. The neutron radiographic technique is non-intrusive and requires no special transparent window region. This is the first time this technique has been used in an electrically heated pressurized flow loop. This unique experimental method offers the opportunity to observe and record on videotape, flow patterns and transient behavior of two-phase flow inside opaque containers without disturbing the environment. In this study the test sections consisted of stainless steel tubes with a 1.27 cm outer diameter and wall thicknesses of 0.084 and 0.124 cm. The experiments were carried out at the Pennsylvania State University 1 MW TRIGA reactor facility utilizing a Precise Optics neutron radiography camera. The inlet water temperature to the test section was varied between 120 deg. C and 170 deg. C...

  3. Analysis by neutron activation in moss samples for the determination of Cr, Se, As and Hg; Analisis por activacion neutronica en muestras de musgos para la determinacion de Cr, Se, As y Hg

    Energy Technology Data Exchange (ETDEWEB)

    Mejia C, R.; Garcia R, G. [Instituto Tecnologico de Toluca, Departamento de Posgrado, Av. Tecnologico s/n, Fraccionamiento La Virgen, 52149 Metepec, Estado de Mexico (Mexico); Lopez R, C.; Avila P, P.; Longoria G, L. C., E-mail: rosario.mejia@inin.gob.mx [ININ, Departamento del Reactor, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2012-10-15

    This research work, presents a study of environmental monitoring in the Metropolitan Area of Toluca Valley using as bio-monitors to the mosses (bryophytes) native of different sites, analyzing the concentrations of As, Cr, Hg and Se, present in its structure. The analysis technique used to identify and to quantify to these elements was the Analysis by Neutron Activation, a nuclear analytic technique that allowed determining the concentrations at track level for its great versatility. Likewise the morphological study of the bryophyte Leskea angustata is presented by scanning electron microscopy. (Author)

  4. Neutron Compton scattering as a molecular characterization technique: A study on NaHF2

    International Nuclear Information System (INIS)

    Inelastic neutron scattering experiments were performed at intermediate and high momentum transfers, up to 85-90 A ring -1, to study the proton momentum distribution in polycrystalline sodium hydrogen fluoride (NaHF2) at low temperature (below 5 K). The H mean kinetic energy was extracted and compared to the results from hydrogen-projected density of phonon states derived from intermediate momentum transfer inelastic neutron scattering and lattice dynamics simulations. A reasonable agreement between the two figures was found. In addition, relevant aspects of high momentum transfer neutron scattering from NaHF2 were explored in detail, ranging from an alternative evaluation of final state effects to the role played by the instrumental resolution and to the possibility to reconstruct the potential felt by a proton from its momentum distribution

  5. Characterization of the storage pool of the Neutron Standards Laboratory of CIEMAT, using Monte Carlo techniques

    International Nuclear Information System (INIS)

    Neutron Standards Laboratory of CIEMAT in Spain is a brand new irradiation facility, with 241Am-Be (185 GBq) and 252Cf (5 GBq) calibrated neutron sources which are stored in a water pool with a concrete cover. From this storage place an automated system is able to take the selected source and place it in the irradiation position, 4 m over the ground level and in the geometrical center of the Irradiation Room with 9 m (length) x 7.5 m (width) x 8 m (height). For calibration or irradiation purposes, detectors or materials can be placed on a bench but it is possible to use the pool (1.0 m x 1.5 m and more than 1.0 m depth) for long time irradiations in thermal neutron fields. For this reason it is essential to characterize the pool itself in terms of neutron spectrum. In this document, the main features of this facility are presented and the characterization of the storage pool in terms of neutron fluence rate and neutron spectrum has been carried out using simulations with MCNPX-2.7.e code. The MCNPX-2.7.e model has been validated using experimental measurements outside the pool (Bert hold LB6411). Inside the pool, the fluence rate decreases and the spectra is thermalized with the distance to the 252Cf source. This source predominates and the effect of the 241Am-Be source in these magnitudes is not shown until positions closer than 20 cm from it. (author)

  6. Characterization of the storage pool of the Neutron Standards Laboratory of CIEMAT, using Monte Carlo techniques

    Energy Technology Data Exchange (ETDEWEB)

    Campo B, X.; Mendez V, R.; Embid S, M. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Av. Complutense 40, 28040 Madrid (Spain); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas (Mexico); Sanz G, J., E-mail: xandra.campo@ciemat.es [Universidad Nacional de Educacion a Distancia, Escuela Tecnica Superior de Ingenieros Industriales, C. Juan del Rosal 12, 28040 Madrid (Spain)

    2014-08-15

    Neutron Standards Laboratory of CIEMAT in Spain is a brand new irradiation facility, with {sup 241}Am-Be (185 GBq) and {sup 252}Cf (5 GBq) calibrated neutron sources which are stored in a water pool with a concrete cover. From this storage place an automated system is able to take the selected source and place it in the irradiation position, 4 m over the ground level and in the geometrical center of the Irradiation Room with 9 m (length) x 7.5 m (width) x 8 m (height). For calibration or irradiation purposes, detectors or materials can be placed on a bench but it is possible to use the pool (1.0 m x 1.5 m and more than 1.0 m depth) for long time irradiations in thermal neutron fields. For this reason it is essential to characterize the pool itself in terms of neutron spectrum. In this document, the main features of this facility are presented and the characterization of the storage pool in terms of neutron fluence rate and neutron spectrum has been carried out using simulations with MCNPX-2.7.e code. The MCNPX-2.7.e model has been validated using experimental measurements outside the pool (Bert hold LB6411). Inside the pool, the fluence rate decreases and the spectra is thermalized with the distance to the {sup 252}Cf source. This source predominates and the effect of the {sup 241}Am-Be source in these magnitudes is not shown until positions closer than 20 cm from it. (author)

  7. Amino acids analysis by neutron cross-section techniques - Part III

    Energy Technology Data Exchange (ETDEWEB)

    Voi, Dante L.; Ferreira, Francisco de O. [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)]. E-mail: dante@ien.gov.br; Rocha, Helio F. da [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Puericultura e Pediatria Martagao Gesteira (IPPMG)]. E-mail: hrocha@gbl.com.br

    2007-07-01

    To continue the work initiated some time ago, about neutron cross section determinations of amino acids, which are directly encoded for protein synthesis by the standard genetic code, we are now measuring six more amino acids samples, with more complex structures to complete the project. All these amino acids are used in enteral and parenteral administration in hospital patients for nutritional applications. The present calculations are a little more difficult because of a new proceeding introduced in the method to explain its molecular structures and obtain its molecular formulae. These amino acids present different radical and elements related to the compounds available in the previous works. Each one, present different structure and freedom grade of movement related to the types of radicals linked in the repetitive structure. In that way, neutron cross section values change with the chemical binding intensities. These details obligate us to search new compounds with new molecular structures to obtain neutron cross sections for posterior comparison , meanly compounds including nitrogen, sulfur and oxygen groups linked to hydrogen atoms. At this time, individual amino acid samples of proline, glutamine, lysine, arginine, histidine, and glutamic acid were measured. It was used the neutron crystal spectrometer installed at the J-9 irradiation channel of the 1 kW Argonauta Reactor of the Instituto de Engenharia Nuclear (IEN). Gold and D{sub 2}O high purity samples were used for the experimental system calibration. Neutron cross section values were calculated from chemical composition, conformation and molecular structure analysis of the materials. Literature data were manipulated by parceling and grouping neutron cross-sections. (author)

  8. Application of new radiation detection techniques at the Paul Scherrer Institut, especially at the spallation neutron source

    CERN Document Server

    Lehmann, E; Williams, T; Pralong, C

    1999-01-01

    The demands on modern irradiation detection systems are diverse, encompassing spatial resolution, dynamic range, sensitivity and reproducibility. Nevertheless, there are two important new methods which can satisfy most of these demands in several applications: camera based systems and imaging plates. Imaging plates have primarily been used as gamma- and beta-sensitive detectors in biology and medicine, but are now available also as neutron sensitive systems. These methods are ideally suited for applications in neutron radiography because of their high sensitivity, linearity and digital output. Image processing, quantification of the image data and automated pattern recognition can easily be performed using modern software tools. The imaging plate system at PSI is shared between groups in reactor physics, radiation protection, biology, proton therapy and nuclear medicine. The collected experience from these different interests establishes the basis for a most effective application of this technique. The utilis...

  9. Accessing interior magnetic field vector components in neutron electric dipole moment experiments via exterior measurements, I. Boundary-value techniques

    CERN Document Server

    Plaster, B

    2013-01-01

    We propose a new concept for determining the interior magnetic field vector components in neutron electric dipole moment experiments. If a closed three-dimensional boundary surface surrounding the fiducial volume of an experiment can be defined such that its interior encloses no currents or sources of magnetization, each of the interior vector field components and the magnetic scalar potential will satisfy a Laplace equation. Therefore, if either the vector field components or the normal derivative of the scalar potential can be measured on the surface of this boundary, thus defining a Dirichlet or Neumann boundary-value problem, respectively, the interior vector field components or the scalar potential (and, thus, the field components via the gradient of the potential) can be uniquely determined via solution of the Laplace equation. We discuss the applicability of this technique to the determination of the interior magnetic field components during the operating phase of neutron electric dipole moment experim...

  10. Determination of boron in water solution by an indirect neutron activation technique from a 241Am/Be source

    International Nuclear Information System (INIS)

    Boron content in water solutions has been analysed by Indirect Activation Technique a twin 241Am/Be neutron source with a source strength of 9x106 n/seg. The boron concentration was inferred from the measurement of the activity induced in a vanadium flux monitor. The vanadium rod was located inside the boron solution in a standart geometrical set up with respect to the neutron source. Boron concentrations in the range of 100 to 1000 ppm were determined with an overall accuracy of about 2% during a total analysis time of about 20 minutes. Eventhough the analysis is not selective for boron yet due the rapid, simple and precise nature, it is proposed for the analysis of boron in the primary coolant circuit of Nuclear Power Plants of PWR type. (Author)

  11. Study on bioavailability of zinc for children's diet by using activable isotopic tracer 70Zn and neutron activation analysis techniques

    International Nuclear Information System (INIS)

    Bioavailability of zinc for three groups (low amount of diet zinc, balance amount of diet zinc and high amount of diet zinc) of children's diet is studied by using activable isotopic tracer 70Zn and neutron activation analysis techniques. The results indicate that the fractional absorption of zinc from balance diet zinc group is the highest, up to 33.9%. A procedure of pre-irradiation concentration zinc for fecal samples using anion exchanger is developed, and the enriched 70Zn with isotopic abundance of 18.3% is used for tracer. The mass ratios between 70Zn and 68Zn or 64Zn and their contents between natural zinc and enriched zinc are used to calculate the bioavailability of zinc. Instrumental neutron activation analysis of 64Zn of each original fecal samples and pre-irradiation concentrated zinc samples are used to normalize the chemical yield in order to reduce the uncertainty during the chemical separation procedure

  12. Neutron Radiography

    Directory of Open Access Journals (Sweden)

    A. R. Reddy

    1982-07-01

    Full Text Available The field of neutron radiography with special reference to isotopic neutron radiography has been reviewed. Different components viz., sources, collimators, imaging systems are described. Various designs of neutron radiography facilities, their relative merits and demerits , the appropriateness of each design depending on the object to be radiographed, and economics of each technique are also dealt. The applications of neutron radiography are also briefly presented.

  13. INAA as tool for environment biomonitoring

    International Nuclear Information System (INIS)

    The k0 parametric technique of Neutron Activation was used to determine elements in sediment, soil, forage, cattle feces and milk samples collected in a cattle breeding and agricultural zone in Curvelo city, Minas Gerais state, in Brazil. The samples were collected on the farms close to the banks of the Das Velhas River where there is periodic flood during reasonable rains. Clinic veterinary studies have shown that most animals raised in this region are affected by symptomatologic nervous diseases, still not clearly diagnosed, that suggest intoxication. These pathologies are mostly registered after floods. In this paper, the elements As, Cr, Co and Zn, among others were analyzed. The results obtained in different samples of cattle urine and milk as well as in forage samples suggest that there is an influence of metals that are carried by the Das Velhas River basin upstream water. (author)

  14. INAA as tool for environment biomonitoring

    Energy Technology Data Exchange (ETDEWEB)

    Veado, Maria Adelaide R.V.; Avelar, Artur C.; Oliveira, Arno H. de [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear]. E-mail: marvv@cdtn.br; adelaide@nuclear.ufmg.br; Veado, Julio Cesar Cambraia [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil). Setor de Radioquimica; Menezes, Maria Angela de B.C.; Miguel, Ronaldo Araujo [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Escola de Veterinaria

    2002-07-01

    The k{sub 0} parametric technique of Neutron Activation was used to determine elements in sediment, soil, forage, cattle feces and milk samples collected in a cattle breeding and agricultural zone in Curvelo city, Minas Gerais state, in Brazil. The samples were collected on the farms close to the banks of the Das Velhas River where there is periodic flood during reasonable rains. Clinic veterinary studies have shown that most animals raised in this region are affected by symptomatologic nervous diseases, still not clearly diagnosed, that suggest intoxication. These pathologies are mostly registered after floods. In this paper, the elements As, Cr, Co and Zn, among others were analyzed. The results obtained in different samples of cattle urine and milk as well as in forage samples suggest that there is an influence of metals that are carried by the Das Velhas River basin upstream water. (author)

  15. Biomedical soft contact-lens sensor for in situ ocular biomonitoring of tear contents.

    Science.gov (United States)

    Chu, MingXing; Shirai, Takayuki; Takahashi, Daishi; Arakawa, Takahiro; Kudo, Hiroyuki; Sano, Kenji; Sawada, Shin-ichi; Yano, Kazuyoshi; Iwasaki, Yasuhiko; Akiyoshi, Kazunari; Mochizuki, Manabu; Mitsubayashi, Kohji

    2011-08-01

    A soft contact-lens biosensor (SCL-biosensor) for novel non-invasive biomonitoring of tear fluids was fabricated and tested. Wearing a biosensor on eye enabled the in situ monitoring of tear contents. The biosensor has an enzyme immobilized electrode on the surface of a polydimethyl siloxane (PDMS) contact lens. The SCL-biosensor was fabricated using microfabrication techniques for functional polymers (PDMS and 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer). In investigation of in vitro characterization, the SCL-biosensor showed excellent relationship between the output current and glucose concentration from 0.03 to 5.0 mmol·L(-1), with a correlation coefficient of 0.994. The calibration range covered the reported tear glucose concentrations (0.14 mmol·L(-1)). Based on the result, ocular biomonitoring with the SCL-biosensor was carried out. The SCL-biosensor well worked both in the static state and the dynamic state. The tear glucose level of rabbit was estimated to 0.12 mmol·L(-1) at first and then the tear turnover was successfully calculated to be 29.6 ± 8.42% min(-1). The result indicated that SCL-biosensor is useful for advanced biomonitoring on eye. PMID:21475940

  16. Potential biomonitors for atmospheric pollution

    International Nuclear Information System (INIS)

    Undesirable influence of air pollution on the human health and the ecosystem has led to an increased interest in toxic emission monitoring programs. To fingerprint the countrywide and regional transboundary pollution profiles, extensive direct monitoring network is needed, which is very expensive and laborious. Plant leaves. Mosses and epiphytic lichens are regarded as potential alternate tools for monitoring levels of atmospheric pollution. Mosses and epiphytic lichens, unlike higher plants have no roots and waxy cuticle nor stomata; hence for mineral nutrition they are largely dependent on wet or dry deposition from the atmosphere. This unique feature has been exploited to predict the pollution levels of the areas in which they are grown by analyzing the embodied toxic elements. Sampling of such naturally growing bioindicators is relatively easier and no sophisticated equipment are needed. The aim of this study was to obtain insight into the response of such plants, when exposed in the vicinity of highly polluted areas and subsequently to confirm the agreement between elemental levels in bioindicators and those measured in atmospheric deposition collected directly with air samplers. INAA and AAS techniques were employed for multielement analysis of exposed samples. Definite influence of pollution on the studied bioindicators was observed for some of the heavy metals like Cd, Cu, Pb and Zn. Results obtained in this work indicate the feasibility of using Broussonetia Papyrifera levels and moss as bioindicators for environmental pollution monitoring. This pattern was also confirmed by analyzing the air particulate matters (APM) collected on filters using Gent air sampler. (author)

  17. A comparison in the reconstruction of neutron spectrums using classical iterative techniques

    International Nuclear Information System (INIS)

    One of the key drawbacks to the use of BUNKI code is that the process begins the reconstruction of the spectrum based on a priori knowledge as close as possible to the solution that is sought. The user has to specify the initial spectrum or do it through a subroutine called MAXIET to calculate a Maxwellian and a 1/E spectrum as initial spectrum. Because the application of iterative procedures by to resolve the reconstruction of neutron spectrum needs an initial spectrum, it is necessary to have new proposals for the election of the same. Based on the experience gained with a widely used method of reconstruction, called BUNKI, has developed a new computational tools for neutron spectrometry and dosimetry, which was first introduced, which operates by means of an iterative algorithm for the reconstruction of neutron spectra. The main feature of this tool is that unlike the existing iterative codes, the choice of the initial spectrum is performed automatically by the program, through a neutron spectra catalog. To develop the code, the algorithm was selected as the routine iterative SPUNIT be used in computing tool and response matrix UTA4 for 31 energy groups. (author)

  18. Research and development of coal ash off-belt bulk analyzer based on PGNAA technique using neutron source

    International Nuclear Information System (INIS)

    IAEA-RCA/RAS on NCS project have been operating from 2001 brought a new conception and approach about application of nuclear and nucleonic techniques in member states. Through 4 cycle of projects (RAS/8/089, RAS/8/094, RAS/8/099 and RAS/8/107), by a step-by-sep technical transfer, higher level on later phase, this technical transfer way has corrected disadvantages and opened new applications, helps the member states from passive receiving to active joining into higher level of technical development for particular application, in each member state. A regional demonstration centre has been set up in Hanoi - Vietnam, to train personnel from around the RCA region in the use of this instrumentation. The centre in Hanoi has been set a coal ash determination instruments using back-scattered gamma and coal ash logging instrument using PGNAA methods. In 2008, through project RAS/8/107, IAEA has aided a neutron generator and Vietnam had a responsibility to develop Ash content Bulk Analysis by PGNAA. Prompt gamma neutron activation analysis technique (PGNAA) is one among advanced techniques over the world. Advantages of this technique are fast analysis, good accuracy, sample process is not required, no influences of measurement environment and analysis of almost elements in the periodic table. Based on this issue, project Research and development of PGNAA coal ash analyser using neutron generator, carried out since 9/2009, finished in 9/2011 have achieved the first achievements in fast coal ash determination. Developed Ash content Bulk Analysis by PGNAA has following technical parameters: result of coal ash determined has absolute error less than 1%; uses Cf-252 neutron source with neutron flux of 0.85 x 106 n/s; uses BGO detector with size of 51 x 51mm, 2000 channels of ADC; analysis time is 600 s; mass of analysed coal sample is 700 kg; PC connected via USB interface on Window XP; neutron dose and gamma dose around the instruments are less than allowed doses in IAEA safety

  19. Activities of research-reactor-technology project in FNCA from FY2005 to FY2007. Sharing neutronics calculation technique for core management and utilization of research reactors

    International Nuclear Information System (INIS)

    RRT project (Research-Reactor-Technology Project) was carried out with the theme of 'sharing neutronics calculation technique for core management and utilization of research reactors' in the framework of FNCA (Forum for Nuclear Cooperation in Asia) from FY2005 to FY2007. The objective of the project was to improve and equalize the level of neutronics calculation technique for the reactor core management among participating countries to assure the safe and stable operation of research reactors and the promotion of the effective utilization. Neutronics calculation codes, namely SRAC code system and MVP code, were adopted as common codes. Participating countries succeeded in applying the common codes to analyzing the core of each domestic research reactor. Some participating countries succeeded in applying the common codes to analyzing for utilization of own research reactors. Activities of RRT project have improved and equalized the level of neutronics calculation technique among participating countries. (author)

  20. Biomonitoring of atmospheric pollution (with emphasis on trace elements) - BioMAP. Proceedings of an international workshop

    International Nuclear Information System (INIS)

    Some organisms accumulate atmospheric contaminants over certain periods of time and concentrate them, thus allowing reliable analytical measurements if the organisms are suitably chosen. Measurements of contaminants accumulated by such organisms (biomonitors) provide information on the integrated exposure over an extended period of time. They may also be present in remote areas, and no expensive technical equipment is involved in collecting them. Therefore, biomonitoring can be an effective tool for pollutant mapping and trend monitoring by real time and retrospective analysis. The IAEA is making concerted efforts to promote the practical use of nuclear and related analytical techniques in studies of non-radioactive environmental pollutants that may impact human health, and one of the main emphases is on studying air contaminants. The idea of organizing a workshop on biomonitoring atmospheric pollution arose during an IAEA Technical Co-operation Project on Monitoring of Trace Element Air Pollution, carried out at the Instituto Tecnologico e Nuclear (ITN), Portugal, with substantial technical support by the Interfaculty Reactor Institute (IRI) of the Delft University of Technology (TUDelft), Netherlands. The International Workshop on Biomonitoring of Atmospheric Pollution (With Emphasis on Trace Elements) - BioMAP, was held in Lisbon, Portugal, from 21 to 24 September 1997. The meeting was organized in co-operation with the Instituto Tecnologico e Nuclear

  1. Vapor fraction measurements in a steam-water tube at up to 15 bar using neutron radiography techniques

    Science.gov (United States)

    Glickstein, S. S.; Murphy, J. H.; Joo, H.

    1999-11-01

    Real-time neutron radiography has been used to study the dynamic behavior of two-phase flow and measure the time averaged vapor fraction in a heated metal tube containing boiling steam-water operating at up to 15 bar pressure. The neutron radiographic technique is non-intrusive and requires no special transparent window region. This is the first time this technique has been used in an electrically heated pressurized flow loop. This unique experimental method offers the opportunity to observe and record on videotape, flow patterns and transient behavior of two-phase flow inside opaque containers without disturbing the environment. In this study the test sections consisted of stainless steel tubes with a 1.27 cm outer diameter and wall thicknesses of 0.084 and 0.124 cm. The experiments were carried out at the Pennsylvania State University 1 MW TRIGA reactor facility utilizing a Precise Optics neutron radiography camera. The inlet water temperature to the test section was varied between 120°C and 170°C and the flow rate set to 2.3 l/min. Tsat is 200°C at these conditions. The tube was resistively heated by passing high currents (˜1000 A) through the stainless steel wall. Scattering due to water in the ˜1 cm tube is significant and Monte Carlo calculations simulating the experiment were made to correct for this effect on the vapor fraction measurement. Details of the experimental technique, methods for analyzing the data and the results of the experiments are discussed.

  2. Biomonitoring Equivalents for interpretation of silver biomonitoring data in a risk assessment context.

    Science.gov (United States)

    Aylward, Lesa L; Bachler, Gerald; von Goetz, Natalie; Poddalgoda, Devika; Hays, Sean M; Nong, Andy

    2016-08-01

    Silver is widely used as an antimicrobial agent in both ionic and nanoparticle forms, and general population exposure to silver can occur through the presence of trace levels in foods and dusts, through dermal contact with treated textiles, from use of wound care products, and other sources. Biomonitoring for silver in blood or urine in persons in the general population is being conducted by the Canadian Health Measures Survey (CHMS). Tolerable exposure guidance values for silver designed to prevent adverse effects of excess exposure are available from the United States Environmental Protection Agency (an oral reference dose, or RfD), from the United States Food and Drug Administration (a draft provisional tolerable intake, or TI) and from literature evaluations of recent data on responses to nanoparticle silver (a recommended tolerable daily intake, or TDI). A current physiologically-based pharmacokinetic model is used to estimate Biomonitoring Equivalents (BEs) for silver, which are steady-state biomarker concentrations consistent with the RfD, provisional TI, or recommended TDI (BERfD, BETI, or BETDI, respectively). The BE values based on silver in whole blood range from 0.2 to 0.9μg/L. BE values for silver in urine were not derived due to low confidence in the predicted steady-state urinary silver excretion rates. Comparison of general population biomonitoring data from Canada to the derived BE values indicate that general population exposure levels are generally below levels consistent with current risk assessment-derived exposure guidance values. PMID:27283208

  3. Application of new radiation detection techniques at the Paul Scherrer Institut, especially at the spallation neutron source

    Science.gov (United States)

    Lehmann, E.; Pleinert, H.; Williams, T.; Pralong, C.

    1999-11-01

    The demands on modern irradiation detection systems are diverse, encompassing spatial resolution, dynamic range, sensitivity and reproducibility. Nevertheless, there are two important new methods which can satisfy most of these demands in several applications: camera based systems and imaging plates. Imaging plates have primarily been used as γ- and β-sensitive detectors in biology and medicine, but are now available also as neutron sensitive systems. These methods are ideally suited for applications in neutron radiography because of their high sensitivity, linearity and digital output. Image processing, quantification of the image data and automated pattern recognition can easily be performed using modern software tools. The imaging plate system at PSI is shared between groups in reactor physics, radiation protection, biology, proton therapy and nuclear medicine. The collected experience from these different interests establishes the basis for a most effective application of this technique. The utilisation of detector systems based on CCD-cameras have other advantages, like low acquisition time, high frame rates, reproducibility as well as high dynamic range. These detectors are applied to investigations of time dependent processes, distribution analyses and quantitative studies. The new radiography facility NEUTRA at the spallation source SINQ provides excellent conditions for neutron radiography studies. Some first examples of investigations with imaging plates and the CCD-camera system are given.

  4. Study on bioavailability of dietary iron of women by using activable isotopic tracer and neutron activation analysis techniques

    International Nuclear Information System (INIS)

    The bioavailability of diet iron of 10 healthy young women in Beijing area is studied by using two enriched isotopes 54Fe and 58Fe, and neutron activation analysis techniques. The abundance of 54Fe and 58Fe is 61.4% and 23.4%, respectively. In additional, the atomic absorption spectrometry is employed to measure total iron in fecal samples. Dysprosium, rarely absorbed by human body, is used to monitor the residence time of tracer isotopes in order to collect the fecal samples completely. The results show that the bioavailability of dietary iron in young women is (14.9 +- 3.9)%

  5. Use of the neutron diffraction - H/D exchange technique to determine the conformational dynamics of trypsin

    International Nuclear Information System (INIS)

    Reported here are studies analyzing the extent and nature of the inherent conformational fluctuations in trypsin by neutron diffraction - hydrogen exchange techniques. The pattern of exchange investigates systematic relationships between exchangeable sites and the structural and chemical properties of the molecule. Our findings that pH 7, 200 and 1 year of soaking all sites of trypsin are fully exchanged except those which are especially well protected by the structure. Essentially all the sites in which the peptide hydrogens are bonded directly to water molecules - either in the bulk solvent regions or in interior clusters - are fully exchanged. 41 references, 10 figures

  6. Visualization and measurements of two-phase flow in metallic ducts using neutrons as microscopic probes. 2. Measurements of some flow characteristics by image processing techniques

    International Nuclear Information System (INIS)

    In order to apply the neutron radiography technique to fluid research, quantitative analyses of high-frame-rate neutron radiographs of air-water flows in a narrow rectangular duct were demonstrated by using image processing techniques. From the geometrical information of the images, the flow regime, bubble rising velocity, water-layer thickness, and interfacial area calculated by multiplying the interfacial length by the channel gap and size distribution of bubbles with diameter greater than 1 mm could be measured by the image processing technique. From the gray levels of the images, the spatial and temporal averaged void fractions and the void profile across the duct could also be measured by the image processing technique. It was clarified that the limited value of the measurable liquid-film thickness with the neutron radiography technique was calculated by an error analysis. It was shown quantitatively that the measurement error decreased by integrating the image temporally. (author)

  7. Development of techniques for the neutron radiography of CF188 flight control surfaces

    Science.gov (United States)

    Bennett, L. G. I.; Bickerton, M. L.; Lewis, W. J.

    1999-11-01

    A neutron radiography facility previously installed on the SLOWPOKE-2 research reactor at the Royal Military College of Canada has been used to gain experience with the inspection of flight control surfaces from the CF188 fighter aircraft. Through operating the facility in a temporary manner in terms of handling and shielding for this application, over 500 radiographs were made for more than three aircraft. Moisture and corrosion were discovered in the honeycomb structure and hydration was found in the composite and adhesive layers. The experience also indicated a need to characterize the neutron beam, to decrease the exposure time by finding a faster film and conversion screen combination, and to develop a gauge to evaluate the moisture trapped in the honeycomb cells of flight control surfaces.

  8. Retinue of the beans roots growth by using neutron radiography technique

    International Nuclear Information System (INIS)

    Agricultural practices frequently cause the development of a soil compacted layer below the surface. These compacted layers restrict the root penetration into deeper layers of soil, in search for water. It is proposed to monitor, using Non Destructive Test, the roots growth due to the planting of standard seeds in different agricultural soils, in function of their compactness and humidity. It will be used the neutrons beams derived from an irradiation channel called J-9 of the Reactor Argonauta (IEN/CNEN), so that the neutron radiographic images of the soil-plant system can be obtained. Each root can be evaluated for its ability to penetrate into compacted soil layers; this fact would mean an optimization of agricultural harvests. (author)

  9. Detection of microorganisms in culture medium through the neutron radiographic technique

    International Nuclear Information System (INIS)

    The study aims to obtain a more effective and faster method for the detection of bacteria in several culture media, such as potable water and blood. After the process growth in the culture medium, separation and suspension in buffer solution based in boron, the bacteria are deposited in track detectors that are submitted to thermal neutron beams (neutron flux: 2,2 x 105 n.cm-2.s-1), resulting from the channel J-9 of the Argonauta research reactor, from the Nuclear Engineering Institute, IEN/CNEN. The latent tracks arisen from the alpha particles proceeding from the reaction B (η, α) Li and, after having been revealed, are analyzed by an optical microscope that allows to detect the existence of the bacteria. Afterwards, they were analyzed in a nanoscope which helps the identification of the tracks of the alpha particles. (author)

  10. Determination of silver, gold, zinc and copper in mineral samples by various techniques of instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Using the method of instrumental neutron activation analysis, mineral exploration samples were analyzed in order to determine the concentrations of silver, gold, zinc and copper; these minerals being the main products of benefit of Tizapa and Cozamin mines. Samples were subjected to various techniques, where the type of radiation and counting methods were chosen based on the specific isotopic characteristics of each element. For calibration and determination of concentrations the comparator method was used, certified standards were subjected to the same conditions of irradiation and measurement that the prospecting samples. The irradiations were performed at the research reactor TRIGA Mark II of the University of Texas at Austin. The silver concentrations were determined by Cyclical Epithermal Neutron Activation Analysis. This method in combination with the transfer pneumatic system allowed a good analytical precision and accuracy in prospecting for silver, from photo peak measurement 657.7 keV of short half-life radionuclide 110Ag. For the determination of gold and zinc, Epithermal Neutron Activation Analysis was used, the photo peaks analyzed corresponded to the energies 411.8 keV of radionuclide 199Au and 438.6 keV of metastable radionuclide 69mZn. On the other hand, copper quantification was based on the photo peak analysis of 1039.2 keV produced by the short half-life radionuclide 66Cu, by Thermal Neutron Activation Analysis. The photo peaks measurement corresponding to gold, zinc and copper was performed using a Compton suppression system, which allowed an improvement in the signal to noise relationship, so that better detection limits and low uncertainties associated with the results were obtained. Comparing elemental concentrations the highest values in silver, zinc and copper was for samples of mine Tizapa. Regarding gold values were found in the same range for both mines. To evaluate the precision and accuracy of the methods used, various geological

  11. Dosimetric evaluation of the Fricke gel dosimeter using the spectrophotometric technique for application in electron and neutron dosimetry

    International Nuclear Information System (INIS)

    In this work the main dosimetric characteristics of the Fricke Xylenol Gel (FXG) solution were established for further application in the measurement of dose distribution of clinical electron fields. The dose-response curves of the FXG in a neutron field were also evaluated for the research in Boron Neutron Capture Therapy (BNCT) and industrial electron fields. The standard reading technique was the spectrophotometric. For the clinical field, the intra and inter-batch reproducibility are better than 1.4% and 5.1 %, respectively, the response presents a linear behavior for doses ranging from 0.2 to 40 Gy independently of the energy and the dose rate in the studied ranges. Due to the effects of the FXG natural oxidation, the optimum elapsed time between FXG preparation and irradiation was established as 24h period and the behavior of the dose-response curve of the FXG using the variation in the absorbance relative to the non-irradiated dosimeter as a basis during the whole studied period were not altered. The dose-response to the industrial electron beam presented an exponential decreasing behavior and the neutron beam for research in BNCT presented a linear behavior for the complete studied dose range. According to the obtained results for the different types of radiation studied for the FXG, there was no change in the position of the characteristic bands of the absorption spectrum due to the interaction of these radiation types. Additional tests were performed to determine the digital photographic imaging of FXG analyses viability and the application of FXG dosimetry on intracavitary brachytherapy. The good performance of the FXG dosimeter in the tests that were carried out indicates that this dosimeter may be applied to the tri-dimensional dose evaluation in radiotherapic treatments using electrons and neutron beams. (author)

  12. Investigation of the fast neutron induced (n, α) reaction. (Experimental techniques)

    International Nuclear Information System (INIS)

    For investigation of the fast neutron induced (n, α)-reaction, two grid-type gas-filled twin ionization chambers were developed and tested. Using the ionization chambers, the energy spectra, angular distributions and cross sections of the (n, α)-reaction were measured around En=5 MeV for 40Ca, 58Ni and 64Zn. 27 refs., 20 figs., 1 tab

  13. NCT-ART - a neutron computer tomography code based on the algebraic reconstruction technique

    International Nuclear Information System (INIS)

    A computer code is presented, which calculates two-dimensional cuts of material assemblies from a number of neutron radiographic projections. Mathematically, the reconstruction is performed by an iterative solution of a system of linear equations. If the system is fully determined, clear pictures are obtained. Even for an underdetermined system (low number of projections) reasonable pictures are reconstructed, but then picture artefacts and convergence problems occur increasingly. (orig.) With 37 figs

  14. Application of the k0 parametric neutron activation technique in the industrial reforestation soil analysis

    International Nuclear Information System (INIS)

    This work identifies and establishes the concentration of some minerals nutrients in Mata Atlantica and Vale do Aco Eucalyptus (Minas Gerais State, Brazil) soils. The k0 method of analysis with neutron activation and X-ray fluorescence were used. Reference material were used to check the accuracy of the analytical results. The k0 method is being introduced in CDTN using the CDTN/CNEN-B H IPR-R1 TRIGA Mark I reactor. (author). 5 refs., 2 tabs

  15. Trace element analysis of human head hair by neutron activation technique

    International Nuclear Information System (INIS)

    28 elements in reference hair sample (HH-1) and 44 hair samples of Seoul, Korea have been analyzed by instrumental neutron activation analysis. The analytical results of reference sample agreed well with those of the IAEA report within 10% deviation except those of some elements. For the 44 hair samples of Seoul, the range of content of each element is fallen in +-3σ from his mean value if rejecting one or two of the highest data. (author)

  16. Observation of oxygen Frenkel disorder in uranium dioxide above 2000 K using neutron scattering techniques

    International Nuclear Information System (INIS)

    Diffraction and coherent diffuse quasielastic scattering of neutrons have been used to investigate Frenkel disorder of the oxygen sublattice in single crystals of stoichiometric UO2. Measurements were made up to 2900 K using a special high-temperature furnace. The results provide the first direct evidence for the occurrence of Frenkel disorder in UO2 and enable estimates of the defect concentration and activation energy to be made. (author)

  17. Residual stresses assessment in coated materials: complementarity between Neutron and X-ray techniques

    Czech Academy of Sciences Publication Activity Database

    Rogante, M.; Mikula, Pavol; Vrána, Miroslav

    Zürich : Trans Tech Publications, 2011 - (Šandera, P.), Roč. 465, 259-262 ISBN 978-3-03785-006-0. ISSN 1013-9826. [6th International Conference on Materials Structure and Micromechanics of Fracture. Brno (CZ), 28.06.2010-30.06.2010] R&D Projects: GA ČR GAP204/10/0654 Institutional support: RVO:61389005 Keywords : Coatings * Residual stresses * Neutron diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism

  18. Residual Stresses Assessment in Coated Materials: Complementarity between Neutron and X-Ray Techniques

    Czech Academy of Sciences Publication Activity Database

    Rogante, M.; Mikula, Pavol; Vrána, Miroslav

    Brno : VUTIUM Brno, 2010 - (Šandera, P.), s. 1-158 ISBN 978-80-214-4112-5. [Proceedings of the International conference on materials structure and micromechanics of fracture (MSMF6). Brno (CZ), 28.06.2010-30.06.2010] R&D Projects: GA ČR GAP204/10/0654 Institutional research plan: CEZ:AV0Z10480505 Keywords : Polysrystalline materials * Residual stress * Neutron diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism

  19. Use of Biomonitoring Data to Evaluate Methyl Eugenol Exposure

    OpenAIRE

    Robison, Steven H.; Barr, Dana B.

    2006-01-01

    Methyl eugenol is a naturally occurring material found in a variety of food sources, including spices, oils, and nutritionally important foods such as bananas and oranges. Given its natural occurrence, a broad cross-section of the population is likely exposed. The availability of biomonitoring and toxicology data offers an opportunity to examine how biomonitoring data can be integrated into risk assessment. Methyl eugenol has been used as a biomarker of exposure. An analytical method to detec...

  20. Neutron total cross section measurements with the {sup 6}Li-ZnS(Ag) scintillator (BC702) employing a neutron and noise separation technique

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Sung Gyun; Kye, Yong Uk; Cho, Moo Hyun [Pohang University of Science and Technology, Pohang (Korea, Republic of); Namkung, Won [Pohang Accelerator Laboratory, Pohang (Korea, Republic of); Kim, Gui Nyun [Kyungpook National University, Daegu (Korea, Republic of); Lee, Man Woo; Kang, Yeong Rok [Dongnam Institute of Radiological and Medical Science, Busan (Korea, Republic of)

    2014-05-15

    The neutron total cross-section of natural Dy has been measured in the energy region from 0.01 to 100 eV by using the neutron time-of-flight method at Pohang Neutron Facility, which consists of an electron linear accelerator, a water-cooled Ta target with a water moderator, and a timeof-flight path with an 11-m length. A {sup 6}Li-ZnS(Ag) scintillator with a diameter of 12.5 cm and a thickness of 1.5 cm has been used as a neutron detector, and a metallic Dy plate has been used for the neutron transmission measurement. The background level has been determined by using notch filters of Co, Ta, and Cd sheets. In order to reduce the gamma rays from Bremsstrahlung and from neutron capture, we have employed a neutron-gamma separation system based on their different pulse shapes.

  1. Biomonitoring of trace element air pollution: Principles, possibilities and perspectives

    International Nuclear Information System (INIS)

    The present paper discusses the biomonitoring of trace element air pollution. Much attention is given to both lichens and mosses as the dominant plant species used in biomonitoring surveys. Biomonitoring is regarded as a means to assess trace element concentrations in aerosols and deposition. This implies that the monitor should concentrate the elements of interest and quantitatively reflect its elemental ambient conditions. Environmental impact on the biomonitor's behaviour is viewed as resulting in changes in the dose-response relationships. The current literature is briefly reviewed, for plant's behaviour modelling, for laboratory studies on physiological processes responsible for accumulation, retention, and release, and for fieldwork on quantification of dose-response relationships. Monitoring of elemental atmospheric availability is presented as deriving its relevance from presumed impact on both ecosystem performance and human health; source apportionment is regarded as an important parallel result for purposes of emission regulatory management. For source apportionment, the paper argues in favour of multi-elemental determinations, supplemented by information on organic compounds and elemental chemical forms. Furthermore, the discussion points towards more explicit coupling of biomonitoring data to knowledge and databases on emission registration, ecosystem performance, and human health. This means that multidisciplinary programs should be set up, which accommodate expert inputs from biomonitoring, emission control programs, analytical chemistry, ecology, and epidemiology. (author)

  2. Biomonitoring test procedures and biological criteria

    Energy Technology Data Exchange (ETDEWEB)

    Kszos, L.A. [Oak Ridge National Lab., TN (United States); Lipschultz, M.J. [City of Las Vegas, NV (United States); Foster, W.E. [Saint Mary`s Coll., Winona, MN (United States)

    1997-10-01

    The Water Environment Federation recently issued a special publication, Biomonitoring in the Water Environment. In this paper, the authors highlight the contents of the chapter 3, Biomonitoring Test Procedures, identify current trends in test procedures and introduce the concept of biological criteria (biocriteria). The book chapter (and this paper) focuses on freshwater and marine chronic and acute toxicity tests used in the National Pollutant Discharge Elimination System (NPDES) permits program to identify effluents and receiving waters containing toxic materials in acutely or chronically toxic concentrations. The two major categories of toxicity tests include acute tests and chronic tests. The USEPA chronic tests required in NPDEs permits have been shortened to 7 days by focusing on the most sensitive life-cycle stages; these tests are often referred to as short-term chronic tests. The type of test(s) required depend on NPDES permit requirements, objectives of the test, available resources, requirements of the test organisms, and effluent characteristics such as variability in flow or toxicity. The permit writer will determine the requirements for toxicity test(s) by considering such factors as dilution, effluent variability, and exposure variability. Whether the required test is acute or chronic, the objective of the test is to estimate the safe or no effect concentration which is defined as the concentration which will permit normal propagation of fish and other aquatic life in the receiving waters. In this paper, the authors review the types of toxicity tests, the commonly used test organisms, and the uses of toxicity test data. In addition, they briefly describe research on new methods and the use of biological criteria.

  3. Particle Imaging Velocimetry Technique Development for Laboratory Measurement of Fracture Flow Inside a Pressure Vessel Using Neutron Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Polsky, Yarom [ORNL; Bingham, Philip R [ORNL; Bilheux, Hassina Z [ORNL; Carmichael, Justin R [ORNL

    2015-01-01

    This paper will describe recent progress made in developing neutron imaging based particle imaging velocimetry techniques for visualizing and quantifying flow structure through a high pressure flow cell with high temperature capability (up to 350 degrees C). This experimental capability has great potential for improving the understanding of flow through fractured systems in applications such as enhanced geothermal systems (EGS). For example, flow structure measurement can be used to develop and validate single phase flow models used for simulation, experimentally identify critical transition regions and their dependence on fracture features such as surface roughness, and study multiphase fluid behavior within fractured systems. The developed method involves the controlled injection of a high contrast fluid into a water flow stream to produce droplets that can be tracked using neutron radiography. A description of the experimental setup will be provided along with an overview of the algorithms used to automatically track droplets and relate them to the velocity gradient in the flow stream. Experimental results will be reported along with volume of fluids based simulation techniques used to model observed flow.

  4. Comparison of neutron activation analysis techniques for the determination of uranium concentrations in geological and environmental materials

    International Nuclear Information System (INIS)

    We have described the determination of uranium in environmental, geological, and agricultural specimens by three different non-destructive nuclear methods. The effectiveness, as defined as the lower limits of detection in this work, of quantifying trace levels of bulk uranium in geological samples was evaluated for several common NAA techniques. These techniques include short-lived and medium-lived neutron activation analysis using thermal and epithermal neutrons; these results were compared with an assessment of Compton suppressed gamma-ray counting. A careful evaluation of three major (n,γ) reactions with chlorine, manganese and sodium that could impede determining low levels of uranium due to high Compton continuums was done. The evaluation of Compton suppressed passive gamma counting revealed that uranium concentrations below 50 mg kg−1 were not adequate to achieve good counting statistics using the 234mPa the second daughter product of 238U. -- Highlights: ► Determination of uranium concentrations in geological, environmental, and agricultural specimens. ► Use of several NAA and passive counting methods. ► Identified several key interferences. ► Use of Compton suppression to minimize effects of interferences

  5. Several techniques for improving energy dependence of a commercial personal neutron dosemeter package based on PADC track detector

    International Nuclear Information System (INIS)

    The practical applicability of several techniques has been investigated for improving the energy dependence of PADC-based personal neutron dosemeter for a commercial dose-assessment service. Under a constraint of no modification in detector material and the fixed chemical processes, two technical attempts have been investigated: an analysis of etch-pit data obtained by microscopic observation and a design of radiator structure. In addition to the number of etch-pits, information of their distribution in terms of various parameters was analyzed. It was found that the two-window method was possibly applicable to the distribution in the etch-pit size and the gray-level. In the latter, a performance of radiator-degrader structure has been confirmed experimentally, and it was found to be one of most promising techniques.

  6. Application of sensitivity analysis to a simplified coupled neutronic thermal-hydraulics transient in a fast reactor using Adjoint techniques

    International Nuclear Information System (INIS)

    In this paper a method to perform sensitivity analysis for a simplified multi-physics problem is presented. The method is based on the Adjoint Sensitivity Analysis Procedure which is used to apply first order perturbation theory to linear and nonlinear problems using adjoint techniques. The multi-physics problem considered includes a neutronic, a thermo-kinetics, and a thermal-hydraulics part and it is used to model the time dependent behavior of a sodium cooled fast reactor. The adjoint procedure is applied to calculate the sensitivity coefficients with respect to the kinetic parameters of the problem for two reference transients using two different model responses, the results obtained are then compared with the values given by a direct sampling of the forward nonlinear problem. Our first results show that, thanks to modern numerical techniques, the procedure is relatively easy to implement and provides good estimation for most perturbations, making the method appealing for more detailed problems. (author)

  7. Predicting fissile content of spent nuclear fuel assemblies with the Passive Neutron Albedo Reactivity technique and Monte Carlo code emulation

    International Nuclear Information System (INIS)

    There is a great need in the safeguards community to be able to nondestructively quantify the mass of plutonium of a spent nuclear fuel assembly. As part of the Next Generation of Safeguards Initiative, we are investigating several techniques, or detector systems, which, when integrated, will be capable of quantifying the plutonium mass of a spent fuel assembly without dismantling the assembly. This paper reports on the simulation of one of these techniques, the Passive Neutron Albedo Reactivity with Fission Chambers (PNAR-FC) system. The response of this system over a wide range of spent fuel assemblies with different burnup, initial enrichment, and cooling time characteristics is shown. A Monte Carlo method of using these modeled results to estimate the fissile content of a spent fuel assembly has been developed. A few numerical simulations of using this method are shown. Finally, additional developments still needed and being worked on are discussed. (author)

  8. Predicting fissile content of spent nuclear fuel assemblies with the passive neutron Albedo reactivity technique and Monte Carlo code emulation

    International Nuclear Information System (INIS)

    There is a great need in the safeguards community to be able to nondestructively quantify the mass of plutonium of a spent nuclear fuel assembly. As part of the Next Generation of Safeguards Initiative, we are investigating several techniques, or detector systems, which, when integrated, will be capable of quantifying the plutonium mass of a spent fuel assembly without dismantling the assembly. This paper reports on the simulation of one of these techniques, the Passive Neutron Albedo Reactivity with Fission Chambers (PNAR-FC) system. The response of this system over a wide range of spent fuel assemblies with different burnup, initial enrichment, and cooling time characteristics is shown. A Monte Carlo method of using these modeled results to estimate the fissile content of a spent fuel assembly has been developed. A few numerical simulations of using this method are shown. Finally, additional developments still needed and being worked on are discussed.

  9. A newly developed technique of wireless remote controlled visual inspection system for neutron guides of cold neutron research facilities at HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Hyung; Cho, Yeong Garp; Kim, Jong In [KAERI, Daejeon (Korea, Republic of)

    2012-10-15

    KAERI developed a neutron guide system for cold neutron research facilities at HANARO from 2003 to 2010. In 2008, the old plug shutter and instruments were removed, and a new plug and primary shutter were installed as the first cold neutron delivery system at HANARO. At the beginning of 2010, all the neutron guides and accessories had been successfully installed as well. The neutron guide system of HANARO consists of the in pile plug assembly with in pile guides, the primary shutter with in shutter guides, the neutron guides in the guide shielding room with secondary shutter, and the neutron guides in the neutron guide hall. Three kinds of glass materials were selected with optimum lengths by considering their lifetime, shielding, maintainability and cost as well. Radiation damage of the guides can occur on the coating and glass by neutron capturing in the glass. It is a big challenge to inspect a guide failure because of the difficult surrounding environment, such as high level radiation, limited working space, and massive hard work for removing and reinstalling the shielding blocks as shown in Fig 1. Therefore, KAERI has developed a wireless remote controlled visual inspection system for neutron guides using an infrared light camera mounted on the vehicle moving in the guide.

  10. A newly developed technique of wireless remote controlled visual inspection system for neutron guides of cold neutron research facilities at HANARO

    International Nuclear Information System (INIS)

    KAERI developed a neutron guide system for cold neutron research facilities at HANARO from 2003 to 2010. In 2008, the old plug shutter and instruments were removed, and a new plug and primary shutter were installed as the first cold neutron delivery system at HANARO. At the beginning of 2010, all the neutron guides and accessories had been successfully installed as well. The neutron guide system of HANARO consists of the in pile plug assembly with in pile guides, the primary shutter with in shutter guides, the neutron guides in the guide shielding room with secondary shutter, and the neutron guides in the neutron guide hall. Three kinds of glass materials were selected with optimum lengths by considering their lifetime, shielding, maintainability and cost as well. Radiation damage of the guides can occur on the coating and glass by neutron capturing in the glass. It is a big challenge to inspect a guide failure because of the difficult surrounding environment, such as high level radiation, limited working space, and massive hard work for removing and reinstalling the shielding blocks as shown in Fig 1. Therefore, KAERI has developed a wireless remote controlled visual inspection system for neutron guides using an infrared light camera mounted on the vehicle moving in the guide

  11. Qualification of tritium production measurement techniques for the HCLL-TBM neutronics experiment

    International Nuclear Information System (INIS)

    Neutronics experiments with a mock-up of the EU Helium-cooled Lithium-Lead Test Blanket Module (HCLL-TBM) are scheduled for 2007 with the aim to validate nuclear design parameters. The HCLL-TBM mock-up will consist mainly of LiPb with 15.7 at-% Li. Tritium production rates (TPR) will be measured with the lithium carbonate method applying a wet chemistry procedure with liquid scintillation counting. However, preliminary calculations reveal that the tritium production density in deeper positions in the assembly will be less than the lower limit for the lithium carbonate method. A higher sensitivity can be expected if the tritium producing events are measured rather than the accumulated tritium activity. Therefore, LiF thermo-luminescence detectors (TLD) are investigated at TU Dresden for their applicability as TPR probes for the HCLL-TBM mock-up experiment. The TPR can be derived from the measured TLD signal if the dose deposited in the TLD can be separated into the contribution from the alpha particles and tritons from the tritium breeding reaction and contributions from photons and charged particles from other reactions. To qualify the method, irradiation experiments with a LiAl-Pb assembly (size 40 cm x 40 cm x 60 cm) simulating the HCLL-TBM mock-up have been performed with the DT neutron generator of TU Dresden. LiF TLD with natural isotopic composition and enriched in 7Li were inserted into the assembly. The DT neutron source fluence was selected so that the local fluence at the detector position is similar to the lowest fluence expected in the HCLL-TBM mock-up during the neutronics experiment. To eliminate the dose from photons and other charged particle reactions, the difference of the TLD signals from the two types of LiF TLDs is used as a measure for the TPR from 6Li. The signal was calibrated with a Li-glass scintillation detector placed at the position of the LiF detector in the center of the assembly. The TPR profile obtained from the LiF detectors placed

  12. Measurement techniques of magnetic properties for evaluation of neutron irradiation damage on austenitic stainless steels

    International Nuclear Information System (INIS)

    The remote-controlled equipment for measurement of magnetic flux density has been developed in order to evaluate the irradiation damage of austenitic stainless steels. Magnetic flux densities by neutron irradiation in austenitic stainless steels, SUS304 and Fast Breeder Reactor grade type 316 (316FR), have been measured by the equipment. The results show that irradiation damage affected to magnetic flux density, and indicate the measuring method of magnetic flux density using a small magnetizer with a permanent magnet of 2 mm in diameter is less affected by specimen shape. (author)

  13. Investigation of thermally induced anion disorder in fluorites using neutron scattering techniques

    DEFF Research Database (Denmark)

    Hutchings, M T; Clausen, Kurt Nørgaard; Dickens, M H;

    1984-01-01

    the coherent diffuse quasielastic neutron scattering from single crystals of three such fluorite compounds PbF2, SrCl2 and CaF2, was investigated. The diffuse scattering intensity, and its energy width, increases with temperature into the fast-ion phase, and when integrated over energy transfer the...... intensity exhibits a characteristic variation with scattering vector, falling on an anisotropic shell in reciprocal space and peaking in certain directions. The diffuse intensity indicates that dynamic correlations exist between the defective anions in the fast-ion-phase. A model of short-lived clusters...

  14. Biopolymer deuteration for neutron scattering and other isotope-sensitive techniques.

    Science.gov (United States)

    Russell, Robert A; Garvey, Christopher J; Darwish, Tamim A; Foster, L John R; Holden, Peter J

    2015-01-01

    The use of microbial biosynthesis to produced deuterated recombinant proteins is a well-established practice in investigations of the relationship between molecular structure and function using neutron scattering and nuclear magnetic resonance spectroscopy. However, there have been few reports of using microbial synthetic capacity to produce labeled native biopolymers. Here, we describe methods for the production of deuterated polyhydroxyalkanoate biopolyesters in bacteria, the polysaccharide chitosan in the yeast Pichia pastoris, and cellulose in the bacterium Gluconacetobacter xylinus. The resulting molecules offer not only multiple options in creating structural contrast in polymer blends and composites in structural studies but also insight into the biosynthetic pathways themselves. PMID:26577729

  15. Neutron Resonance Transmission Analysis (NRTA): A Nondestructive Assay Technique for the Next Generation Safeguards Initiative's Plutonium Assay Challenge

    International Nuclear Information System (INIS)

    This is an end-of-year report for a project funded by the National Nuclear Security Administration's Office of Nuclear Safeguards (NA-241). The goal of this project is to investigate the feasibility of using Neutron Resonance Transmission Analysis (NRTA) to assay plutonium in commercial light-water-reactor spent fuel. This project is part of a larger research effort within the Next-Generation Safeguards Initiative (NGSI) to evaluate methods for assaying plutonium in spent fuel, the Plutonium Assay Challenge. The first-year goals for this project were modest and included: (1) developing a zero-order MCNP model for the NRTA technique, simulating data results presented in the literature, (2) completing a preliminary set of studies investigating important design and performance characteristics for the NRTA measurement technique, and (3) documentation of this work in an end of the year report (this report). Research teams at Los Alamos National Laboratory (LANL), Lawrence Berkeley National Laboratory (LBNL), Pacific Northwest National Laboratory (PNNL), and at several universities are also working to investigate plutonium assay methods for spent-fuel safeguards. While the NRTA technique is well proven in the scientific literature for assaying individual spent fuel pins, it is a newcomer to the current NGSI efforts studying Pu assay method techniques having just started in March 2010; several analytical techniques have been under investigation within this program for two to three years or more. This report summarizes a nine month period of work.

  16. The use of Usnea sp. and Tillandsia capillaries as biomonitors of environmental pollution in Lima city, Peru

    International Nuclear Information System (INIS)

    In order to evaluate pollution in the city of Lima, Peru, an environmental monitoring was carried out using two species of biomonitors: Liquen Usnea sp. and Tillandsia capillaries. Both samples were taken from an uncontaminated area to be exposed during three months in different sampling sites of the city. Then samples were collected, prepared and analyzed by instrumental neutron activation analysis, based k0 method. Results showed important contamination in East and North sites of the city coming from industrial activities and automotive vehicles emissions. (author).

  17. Characterizing a thermal neutron calibration assembly by solid state, nuclear track dosemeters and Monte Carlo technique

    Energy Technology Data Exchange (ETDEWEB)

    Vilela, E.; Morelli, B.; Gualdrini, G.; Burn, K.W.; Monteventi, F.; Fantuzzi, E. [ENEA, Centro Ricerche Ezio Clementel, Bologna (Italy). Dipt. Ambiente

    1998-07-01

    In the present report a thermal neutron assembly consisting of a polyethylene cube for calibrating dosimetric instruments at the ENEA (National Agency for New Technology, Energy and the Environment) Institute for Radiation Protection is described. The characterization of such a facility in terms of the spectral neutron fluence and the ambient dose equivalent rates according to the ICRP60 document is illustrated in detail. Special variance reduction algorithms developed at ENEA allowed satisfactory statistics to be obtained over the whole investigated energy domain. [Italian] Nel presente rapporto viene descritto un insieme per neutroni termici, impiegato nella calibrazione di strumenti dosimetrici presso l'Istituto di Radioprotezione delle ENEA e viene mostrata in dettaglio la caratterizzazione dell'insieme in termini di ratei di fluenza neutronica spettrale e di equivalente di dose ambientale in accorso con il documento ICRP60. Speciali tecniche di riduzione della varianza sviluppate presso l'ENEA hanno consentito di ottenere una statistica soddisfacente su tutto il dominio di energia studiato.

  18. Phase Concentration Determination of Fe16N2 Using State of the Art Neutron Scattering Techniques

    Science.gov (United States)

    Bennett, S. P.; Feygenson, M.; Jiang, Y.; Zande, B. J.; Zhang, X.; Sankar, S. G.; Wang, J. P.; Lauter, V.

    2016-06-01

    Due to limitations on the availability of rare earth elements it is imperative that new high energy product rare earth free permanent magnet materials are developed for the next generation of energy systems. One promising low cost permanent magnet candidate for a high energy magnet is α″-Fe16N2, whose giant magnetic moment has been predicted to be well above any other from conventional first principles calculations. Despite its great promise, the α″ phase is metastable; making synthesis of the pure phase difficult, resulting in less than ideal magnetic characteristics. This instability gives way to a slew of possible secondary phases (i.e. α-Fe, Fe2O3, Fe8N, Fe4N, etc.) whose concentrations are difficult to detect by conventional x-ray diffraction. Here we show how high resolution neutron diffraction and polarized neutron reflectometry can be used to extract the phase concentration ratio of the giant magnetic phase from ultra-small powder sample sizes (~0.1 g) and thin films. These studies have led to the discovery of promising fabrication methods for both homogeneous thin films, and nanopowders containing the highest reported to date (>95%) phase concentrations of room temperature stable α″-Fe16N2.

  19. In vivo monitoring of toxic metals: assessment of neutron activation and x-ray fluorescence techniques

    International Nuclear Information System (INIS)

    To date, cadmium, lead, aluminum, and mercury have been measured in vivo in humans. The possibilities of monitoring other toxic metals have also been demonstrated, but no human studies have been performed. Neutron activation analysis appears to be most suitable for Cd and Al measurements, while x-ray fluorescence is ideally suited for measurement of lead in superficial bone. Filtered neutron beams and polarized x-ray sources are being developed which will improve in vivo detection limits. Even so, several of the current facilities are already suitable for use in epidemiological studies of selected populations with suspected long-term low-level ''environmental'' exposures. Evaluation and diagnosis of patients presenting with general clinical symptoms attributable to possible toxic metal exposure may be assisted by in vivo examination. Continued in vivo monitoring of industrial workers, especially follow-up measurements, will provide the first direct assessment of changes in body burden and a direct measure of the biological life-times of these metals in humans. 50 refs., 4 figs., 2 tabs

  20. Optimization of the indirect at neutron activation technique for the determination of boron in aqueous solutions

    International Nuclear Information System (INIS)

    The purpose of this work was the development of an instrumental method for the optimization of the indirect neutron activation analysis of boron in aqueous solutions. The optimization took into account the analytical parameters under laboratory conditions: activation carried out with a 241Am/Be neutron source and detection of the activity induced in vanadium with two NaI(Tl) gamma spectrometers. A calibration curve was thus obtained for a concentration range of 0 to 5000 ppm B. Later on, experimental models were built in order to study the feasibility of automation. The analysis of boron was finally performed, under the previously established conditions, with an automated system comprising the operations of transport, irradiation and counting. An improvement in the quality of the analysis was observed, with boron concentrations as low as 5 ppm being determined with a precision level better than 0.4%. The experimental model features all basic design elements for an automated device for the analysis of boron in agueous solutions wherever this is required, as in the operation of nuclear reactors. (Author)

  1. Biomonitoring and spatial variability of sulphur dioxide in urban air

    Directory of Open Access Journals (Sweden)

    Éder Lisandro de Moraes Flores

    2011-12-01

    Full Text Available Lichens are recognized as biological indicators of environmental pollution and also biomonitors of air quality due to their response capacity when exposed to polluted environments especially toxic gases such as sulfur dioxide (SO2 carbon dioxide (CO2 heavy metals fluorides ozone nitrogen oxides and peroxyacetyl nitrate. This work evaluated the sulfur dioxide concentration of in the air in Santa Maria city using lichen kind Usnea as biomarker. Extracts including their substrates were collected in an area without the influence of pollutants and exposed in regions of the city with intense automotive traffic. This procedure was repeated throughout four seasons of one year. After each exposure the analysis of sulfur accumulated was done using the turbidimetric technique. The Usnea sp species showed to be good for monitoring of the atmospheric sulfur dioxide. In spite of the fuels commercialized today show low pollutants concentration the increase in the number of automotive vehicles in the urban center in Santa Maria city contributes significantly to the high concentration of sulfur dioxide in the atmospheric air.

  2. Contact allergy and human biomonitoring--an overview with a focus on metals

    DEFF Research Database (Denmark)

    Thyssen, Jacob P; Roeske-Nielsen, Allan; Johansen, Jeanne D

    2011-01-01

    towards the use of human biomonitoring. A few studies have used human biomonitoring methodology to track contact allergens together with information on patch test reactivity. Hypothetically, the internal load of reactive chemicals might modify the immune response to haptens and the propensity to sensitize...... and elicit allergic contact dermatitis or develop tolerance. This review offers a general overview of human biomonitoring, including information about its typical application and methodology. Furthermore, studies that have attempted to perform simultaneous biomonitoring and patch testing are reviewed...

  3. The application of computer technique in routine neutron activation analysis using high resolution gamma ray spectrometry

    International Nuclear Information System (INIS)

    A full system of four computer programs for routine - qualitative and quantitative - neutron activation analysis (NAA) using high resolution gamma ray-spectrometry had been elaborated. The structure and possibilities of the ''data flow'' programs i.e. programs DIDPDP and DIDCDC, dedicated for fast and reliable ''off line'' data transfer between the buffer memory of the spectrometric line (9-track magnetic tape) and the fast access memory (disc) of the used computers PDP-11/45 and CYBER-73 had been presented. The structure and organization of the ''data processing'' programs i.e. programs SAWAPS and MAZYG had been presented as well. The utility and reliability of these programs in the case of the large-scale, routine NAA, exampled by analysis of filters with air polutants, had been tested and discussed. Programs are written mainly in FORTRAN. (author)

  4. Elemental analysis and plant samples at el-Manzala lake by neutron activation analysis technique

    International Nuclear Information System (INIS)

    A soil and a plant samples were taken from two locations, Bahr el-Bakar and Bahr Kados at the Manzala lake, where a high pollution is expected. The samples were especially treated and prepared for investigation by thermal neutron activation analysis (NAA). The irradiation facilities of the first egyptian research reactor (ET-R R-1) and the hyper pure germanium (HPGe) detection system were used for such a type of analysis. Among the 34 identified elements Fe, Co, As, Ru, Cd, Te, La, Sm, Eu, Tb, Hg, Th, and U are of a special significance because of their toxic deleterious impact to organisms. This work is a part of a research project concerning pollution studies on the river nile and some lakes of egypt. The data obtained in the present work stand as a reference basic record for any future follow up of the contamination level. 1 tab

  5. Peripheral dose from neutrons and photons in the radiation treatment of pelvic tumors with conventional technique or VMAT. A review

    International Nuclear Information System (INIS)

    Peripheral neutron and photon doses from external beam radiation therapy are associated with the risk of carcinogenesis in organs distant to the treated volume. In the irradiation of tumors and target volumes in the pelvis with convention photon-radiotherapy beams with high nominal energies (above 15 MeV) are typically used. During the last years volumetric modulated arc therapy (VMAT) techniques have gained a wide-spread use for pelvic treatments. The beam-energies that are primarily used in VMAT are below 10 MeV. Therefore, a reduction in peripheral dose due to the absence of neutrons can be expected when VMAT is utilized. On the other hand the number of monitor units is increased in increased in VMAT, as compared to conventional unmodulated fields, by a factor of two to three. This leads to an increase in transmission dose from the machine's treatment head, such that the potential benefit might be outbalanced. The question, whether the increasing use of VMAT might lead to a reduction of peripheral dose, is the subject of several studies. Those studies use either measurements in phantom settings or Monte-Carlo simulations. A systematic review of the literature shows diverging, and sometimes even contradictory, findings. Therefore, the issue of peripheral dose and the risk for secondary malignancies requires further investigation. In our opinion, the focus should be put on measurements and simulations, but also on modelling of dose-response correlations.

  6. Residual stress in a laser welded EUROFER blanket module assembly using non-destructive neutron diffraction techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, D.J., E-mail: d.hughes@warwick.ac.uk [WMG, University of Warwick, Coventry CV4 7AL (United Kingdom); Koukovini-Platia, E. [CERN, CH-1211 Geneva 23 (Switzerland); Heeley, E.L. [Department of Physical Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

    2014-02-15

    Highlights: • Residual stresses were determined in a welded EUROFER blanket assembly with integrated cooling channels. • Good agreement was seen between experimentally determined and predicted stresses. • We show that microstructure changes that occur in EUROFER steels during welding must be considered for residual stress determination. • An experimental route is proposed for validation of predicted stresses in reactor components using non-destructive diffraction techniques. - Abstract: Whilst the structural integrity and lifetime considerations in welded joints for blanket modules can be predicted using finite element software, it is essential to prove the validity of these simulations. This paper provides detailed analysis for the first time, of the residual stress state in a laser-welded sample with integral cooling channels. State-of-the-art non-destructive neutron diffraction was employed to determine the triaxial stress state and to understand microstructural changes around the heat affected zone. Synchrotron X-ray diffraction was used to probe the variation of strain-free lattice reference parameter around the weld zone allowing correction of the neutron measurements. This paper details an important experimental route to validation of predicted stresses in complex safety-critical reactor components for future applications.

  7. Analysis of the toenail as a biomonitor of supranutritional intake of Zn, Cu, and Mg

    International Nuclear Information System (INIS)

    The toenail was examined as a biological monitor of Mg, Zn, and Cu intake using an observational case control model. The One Source Cohort matched 63 individuals in Columbia Missouri who took the One Source multivitamin with 63 control individuals. The matching criteria were based on age, sex, ethnicity, smoking status, and body mass index. The multivitamin contained supra-nutritional levels of Se, Mg, Cu, and Zn. The toenail clippings were examined for these elements using instrumental neutron activation analysis (INAA). A statistical analysis did not indicate a significant difference for Mg, Cu, or Zn between the nails of One Source supplement users and control subjects (p-4). This internal Se control suggests that the One Source Cohort is largely free from misclassification errors that could interfere with the biomonitor response for the supranutritional intake of Mg, Cu, and Zn. (author)

  8. Gamma, X-ray and neutron techniques for the coal industry

    International Nuclear Information System (INIS)

    Nuclear techniques play a prominent role in all aspects of the coal industry, from exploration through mine development to testing of coal quality during production. The advent of on-line nuclear techniques allows continuous, near real time appraisal of coal quality free from the errors inherent in conventional techniques based on discrete samples. The Advisory Group Meeting reviews the latest developments in this area and makes recommendations on the most promising areas and priorities for future research and development activities. This report records the proceedings of the Advisory Group Meeting. Separate abstracts were prepared for each of the 13 papers in this report

  9. Recommendations for Biomonitoring of Emergency Responders: Focus on Occupational Health Investigations and Occupational Health Research

    OpenAIRE

    Decker, John A.; DeBord, D. Gayle; Bernard, Bruce; Dotson, G. Scott; Halpin, John; Hines, Cynthia J.; Kiefer, Max; Myers, Kyle; Page, Elena; Schulte, Paul; Snawder, John

    2013-01-01

    The disaster environment frequently presents rapidly evolving and unpredictable hazardous exposures to emergency responders. Improved estimates of exposure and effect from biomonitoring can be used to assess exposure–response relationships, potential health consequences, and effectiveness of control measures. Disaster settings, however, pose significant challenges for biomonitoring. A decision process for determining when to conduct biomonitoring during and following disasters was developed. ...

  10. Study of deep level characteristics in the neutrons irradiated Si structures by combining pulsed and steady-state spectroscopy techniques

    Science.gov (United States)

    Gaubas, E.; Kalendra, V.; Ceponis, T.; Uleckas, A.; Tekorius, A.; Vaitkus, J.; Velicka, A.

    2012-11-01

    The standard methods, such as capacitance deep level transient spectroscopy (C-DLTS) and thermally stimulated current (TSC) techniques are unsuitable for the analysis of heavily irradiated devices. In this work, therefore, several steady-state and pulsed techniques have been combined to comprehensively evaluate parameters of radiation defects and functional characteristics of the irradiated Si pin detectors. In order to understand defects created by radiation and evaluate their evolution with fluence, C-DLTS and TSC techniques have been employed to make a baseline identification of the radiation induced traps after irradiation with a rather small neutron fluence of 1012 cm-2. The steady-state photo-ionization spectroscopy (PIS) technique has been involved to correlate thermal- and photo- activation energies for definite radiation defects. A contactless technique for simultaneous measurements of the carrier lifetime and the parameters of deep levels based on microwave probed pulsed photo-conductivity (MW-PC) spectroscopy has been applied to correlate carrier capture cross-sections and densities of the identified different radiation defects. A technique for spectroscopy of deep levels in junction structures (BELIV) based on measurements of barrier capacitance charging current transient changes due to additional spectrally resolved pulsed illumination has been applied to evaluate the functional characteristics of the irradiated diodes. Pulsed spectroscopic measurements were implemented by combining the analysis of generation current and of barrier capacitance charging transients modified by a single fs pulse of illumination generated by an optical parametric oscillator of varied wavelength in the range from 0.5 to 10 μm. Several deep levels with activation energy in the range of 0.18-0.8 eV have been resolved from spectral analysis in the samples of Si grown by magnetic field applied Czochralski (MCz) technology.

  11. US Fish and Wildlife Service lands biomonitoring operations manual

    Energy Technology Data Exchange (ETDEWEB)

    Rope, R.C.; Breckenridge, R.P.

    1993-08-01

    This is Volume 1 of an operations manual designed to facilitate the development of biomonitoring strategies for U.S. Fish and Wildlife Service Lands. It is one component of the U.S. Fish and Wildlife Service Lands Biomonitoring Operations Manual. The Volume contains the Introduction to the Manual, background information on monitoring, and procedures for developing a biomonitoring strategy for Service lands. The purpose of the Biomonitoring Operations Manual is to provide an approach to develop and implement biomonitoring activities to assess the status and trends of U.S. Fish and Wildlife Service trust resources. It also provides field sampline methods and documentation protocols for contaminant monitoring activities. The strategy described in the Manual has been designed as a stand alone process to characterize the presence of contaminants on lands managed by the Service. This process can be sued to develop a monitoring program for any tract of real estate with potential threats from on- or off-site contaminants. Because the process was designed to address concerns for Service lands that span the United States from Alaska to the Tropical Islands, it has a generic format that can be used in al types of ecosystems, however, significant site specific informtion is required to complete the Workbook and make the process work successfully.

  12. Analysis and Assessment of Neutron Backscattering Technique for Landmine Detection%中子背散射探雷技术的分析与评估

    Institute of Scientific and Technical Information of China (English)

    曹琳; 储诚胜; 滕君锐; 胡广春; 熊宗华; 郝樊华; 雷家荣; 陈涵德

    2012-01-01

    The analysis of physics principles of neutron backscattering technique and Monte Carlo simulation were presented for assessment of landmine detection by neutron backscattering technique. The results are greatly valuable for future research and engineering.%本文分析了中子背散射探雷技术的原理,通过数值模拟对中子背散射探雷技术进行研究,并对该技术进行分析评估,为进一步开展中子背散射探雷技术的工程研究提供理论基础.

  13. Baseline study of pesticide residues and toxic contaminants in environmental samples in Thailand by neutron activation technique

    International Nuclear Information System (INIS)

    The technique of neutron activation, both instrumental and radiochemical, is used for the investigation of pesticide residues and contaminants, viz. Hg, Se, As, Cd, Cu, Br, Co and Zn in rice and marine fish in Thailand. More than 500 samples of 6 species including squid of fish caught from polluted and non (less)-polluted areas in Thai waters, and of 17 varieties of non-glutinous rice and 6 varieties of glutinous rice of both brown and milled collected from 21 different rice experiment stations throughout the Kingdom are analyzed. The results of this study positively indicate that there is no contamination in fish and rice in Thailand. Additionally, the baseline concentration of studies trace toxic elements is established. (author)

  14. Direct assignment of molecular vibrations via normal mode analysis of the neutron dynamic pair distribution function technique

    International Nuclear Information System (INIS)

    For over a century, vibrational spectroscopy has enhanced the study of materials. Yet, assignment of particular molecular motions to vibrational excitations has relied on indirect methods. Here, we demonstrate that applying group theoretical methods to the dynamic pair distribution function analysis of neutron scattering data provides direct access to the individual atomic displacements responsible for these excitations. Applied to the molecule-based frustrated magnet with a potential magnetic valence-bond state, LiZn2Mo3O8, this approach allows direct assignment of the constrained rotational mode of Mo3O13 clusters and internal modes of MoO6 polyhedra. We anticipate that coupling this well known data analysis technique with dynamic pair distribution function analysis will have broad application in connecting structural dynamics to physical properties in a wide range of molecular and solid state systems

  15. Direct assignment of molecular vibrations via normal mode analysis of the neutron dynamic pair distribution function technique.

    Science.gov (United States)

    Fry-Petit, A M; Rebola, A F; Mourigal, M; Valentine, M; Drichko, N; Sheckelton, J P; Fennie, C J; McQueen, T M

    2015-09-28

    For over a century, vibrational spectroscopy has enhanced the study of materials. Yet, assignment of particular molecular motions to vibrational excitations has relied on indirect methods. Here, we demonstrate that applying group theoretical methods to the dynamic pair distribution function analysis of neutron scattering data provides direct access to the individual atomic displacements responsible for these excitations. Applied to the molecule-based frustrated magnet with a potential magnetic valence-bond state, LiZn2Mo3O8, this approach allows direct assignment of the constrained rotational mode of Mo3O13 clusters and internal modes of MoO6 polyhedra. We anticipate that coupling this well known data analysis technique with dynamic pair distribution function analysis will have broad application in connecting structural dynamics to physical properties in a wide range of molecular and solid state systems. PMID:26429001

  16. Direct assignment of molecular vibrations via normal mode analysis of the neutron dynamic pair distribution function technique

    Energy Technology Data Exchange (ETDEWEB)

    Fry-Petit, A. M., E-mail: mcqueen@jhu.edu, E-mail: afry@fullerton.edu; Sheckelton, J. P.; McQueen, T. M., E-mail: mcqueen@jhu.edu, E-mail: afry@fullerton.edu [Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218 (United States); Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218 (United States); Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Rebola, A. F.; Fennie, C. J. [Department of Applied Physics, Cornell University, Ithaca, New York 14853 (United States); Mourigal, M.; Valentine, M.; Drichko, N. [Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218 (United States)

    2015-09-28

    For over a century, vibrational spectroscopy has enhanced the study of materials. Yet, assignment of particular molecular motions to vibrational excitations has relied on indirect methods. Here, we demonstrate that applying group theoretical methods to the dynamic pair distribution function analysis of neutron scattering data provides direct access to the individual atomic displacements responsible for these excitations. Applied to the molecule-based frustrated magnet with a potential magnetic valence-bond state, LiZn{sub 2}Mo{sub 3}O{sub 8}, this approach allows direct assignment of the constrained rotational mode of Mo{sub 3}O{sub 13} clusters and internal modes of MoO{sub 6} polyhedra. We anticipate that coupling this well known data analysis technique with dynamic pair distribution function analysis will have broad application in connecting structural dynamics to physical properties in a wide range of molecular and solid state systems.

  17. Direct mass measurements in the light neutron-rich region using a combined energy and time-of-flight technique

    International Nuclear Information System (INIS)

    This experiment has demonstrated that direct mass measurements can be performed (albeit of low precision in this first attempt) using the M proportional to ET2 method. This technique has the advantage that many particle-bound nuclei, produced in fragmentation reactions can be measured simultaneously, independent of their N or Z. The main disadvantage of this approach is that both energy and time-of-flight must be measured precisely on an absolute scale. Although some mass walk with N and Z was observed in this experiment, these uncertainties were largely removed by extrapolating the smooth dependence observed for known nuclei which lie closer to the valley of β-stability. Mass measurements for several neutron-rich light nuclei ranging from 17C to 26Ne have been performed. In all cases these measurements agree with the latest mass compilation of Wapstra and Audi. The masses of 20N and 24F have been determined for the first time

  18. Velocity field measurement in gas-liquid metal two-phase flow with use of PIV and neutron radiography techniques

    International Nuclear Information System (INIS)

    Neutron radiography and PIV (Particle Image Velocimetry) techniques were applied to measurements of velocity field in gas-liquid metal two-phase flow. Visualization and measurements of two-phase flow were conducted using molten lead bismuth and nitrogen gas as working fluids and particles made of gold-cadmium (AuCd3) inter-metallic alloy were employed as the tracer. Discrimination method between bubble and tracer images in two-phase flow was developed based on the σ-scaling method. Time-averaged liquid velocity fields, gas velocity fields and void profile were calculated from discriminated images, respectively. From these measurements, the basic characteristics of gas-liquid metal two-phase mixture were clarified. (author)

  19. Velocity field measurement in gas-liquid metal two-phase flow with use of PIV and neutron radiography techniques

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Y.; Mishima, K. [Kyoto Univ. Kumatori, Research Reactor Institute, Osaka (Japan); Tobita, Y.; Suzuki, T. [O-arai Engineering Center, Power Reactor and Nuclear Fuel Development Corporation (Japan); Matsubayashi, M. [Japan Atomic Energy Institute, Tokai Research Establishment (Japan)

    2001-07-01

    Neutron radiography and PIV (Particle Image Velocimetry) techniques were applied to measurements of velocity field in gas-liquid metal two-phase flow. Visualization and measurements of two-phase flow were conducted using molten lead bismuth and nitrogen gas as working fluids and particles made of gold-cadmium (AuCd{sub 3}) inter-metallic alloy were employed as the tracer. Discrimination method between bubble and tracer images in two-phase flow was developed based on the {sigma}-scaling method. Time-averaged liquid velocity fields, gas velocity fields and void profile were calculated from discriminated images, respectively. From these measurements, the basic characteristics of gas-liquid metal two-phase mixture were clarified. (author)

  20. NAA of copper in its ores by ''2''4''1Am-Be neutron source using the standard addition technique

    International Nuclear Information System (INIS)

    Neutron activation analysis using nuclear reactors as sources of activating particles is a well established technique, which has been described adequately in the literature and has been used for the analysis of a wide range of materials. The ''2''4''1Am-Be neutron source is also a useful source of activating particles for, although the neutron flux is relatively low (approximately 10''5 ncm''-''2 s''-''1) it is adequate for a range of analyses where extreme sensitivity is not of prime importance and offers the advantages of relatively low cost and ease of operation. The determination of Cu in its ores has been investigated for a typical industrial application of ''2''4''1Am-Be neutron activation by method of standard addition

  1. Evaluation of reactivity monitoring techniques in experiments with pulsed neutron source in the Yalina-Booster subcritical assembly; Evaluacion de tecnicas de monitorizacion de la reactividad en experimentos con fuente de neutrones pulsada en el conjunto subcritico Yalina-Booster

    Energy Technology Data Exchange (ETDEWEB)

    Becares, V.; Villamarin, D.; Fernandez-Ordonez, M.; Gonzalez-Romero, E. M.

    2010-07-01

    As a part of EUROTRANS program, it has carried out an experimental campaign focused in the validation of reactivity monitoring techniques in the Yalina-Booster subcritical assembly. The aim of this paper is to present the analysis of part of the experiments results, in particular those carried out with a pulsed neutron source.

  2. Study on determination of antimony in environmental samples by nuclear technique neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Tassiane Cristina Gomes; Saiki, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2010-07-01

    Full text: The Interest on determination of antimony in environmental samples has increased significantly in recent years due to the impact caused by human activities and their potential cumulative toxic at low concentrations, apart from not having known biological function. However, the quantification of antimony has interference problems due to low concentrations that hinder its analysis. Therefore becomes of great interest to establish adequate procedures for neutron activation analysis (NAA) to obtain reliable results in environmental samples. In this context, reference materials INCT-TL-1 Tea Leaves, INCT-MPH -2 Mixed Polish Herbs, CTA-VTL-2 Virginia Tobaco Leaves, White Cabbage BCR-679, IAEA 140/TM Seaweed (Focus sp), IAEA -SL-1 Lake Sediment and IAEA-336 Lichen, were selected for analysis and evaluation of results. Aliquots of these standard synthetic materials and antimony were irradiated in the nuclear research reactor IEA-R1 under thermal neutron flux of approximately 5 x 1012 cm{sup -2} s{sup -1} for a period of 8 or 16 hours. After appropriate decay time, the induced gamma activity of the irradiated samples and standard was measured using hyperpure Ge detector coupled to the digital spectrum analyzer DAS 1000, both from Canberra. The radioisotopes measured with gamma ray energies and the half-life were Sb-122 (E{gamma} = 564keV ; t1=2 = 2:7d) and Sb - 124 (E{gamma} = 1692keV; t1=2 60:2d). Antimony concentrations were calculated by the comparative method and the uncertainties of the results were estimated using statistical error of the sample and standard counts Results obtained in these analyses showed a good agreement with certified values and relative errors varying from 0.78 to 13.8%. The values of the standardized difference or Z-scores obtained were lower than 2, indicating that the obtained data were within the range of certified values at a significance level of 68%, demonstrating the suitability of the method used for determination of antimony

  3. Study on determination of antimony in environmental samples by nuclear technique neutron activation analysis

    International Nuclear Information System (INIS)

    Full text: The Interest on determination of antimony in environmental samples has increased significantly in recent years due to the impact caused by human activities and their potential cumulative toxic at low concentrations, apart from not having known biological function. However, the quantification of antimony has interference problems due to low concentrations that hinder its analysis. Therefore becomes of great interest to establish adequate procedures for neutron activation analysis (NAA) to obtain reliable results in environmental samples. In this context, reference materials INCT-TL-1 Tea Leaves, INCT-MPH -2 Mixed Polish Herbs, CTA-VTL-2 Virginia Tobaco Leaves, White Cabbage BCR-679, IAEA 140/TM Seaweed (Focus sp), IAEA -SL-1 Lake Sediment and IAEA-336 Lichen, were selected for analysis and evaluation of results. Aliquots of these standard synthetic materials and antimony were irradiated in the nuclear research reactor IEA-R1 under thermal neutron flux of approximately 5 x 1012 cm-2 s-1 for a period of 8 or 16 hours. After appropriate decay time, the induced gamma activity of the irradiated samples and standard was measured using hyperpure Ge detector coupled to the digital spectrum analyzer DAS 1000, both from Canberra. The radioisotopes measured with gamma ray energies and the half-life were Sb-122 (Eγ = 564keV ; t1=2 = 2:7d) and Sb - 124 (Eγ = 1692keV; t1=2 60:2d). Antimony concentrations were calculated by the comparative method and the uncertainties of the results were estimated using statistical error of the sample and standard counts Results obtained in these analyses showed a good agreement with certified values and relative errors varying from 0.78 to 13.8%. The values of the standardized difference or Z-scores obtained were lower than 2, indicating that the obtained data were within the range of certified values at a significance level of 68%, demonstrating the suitability of the method used for determination of antimony in this type sample

  4. Improvement of calculational technique on flux distributions in a water phantom caused by narrow thermal neutron beam for neutron capture therapy

    International Nuclear Information System (INIS)

    The thermal neutron flux distribution in a water phantom caused by narrow beam are separately calculated for scattered and non-scattered neutrons. Two-dimensional transport code TWOTRAN in the SRAC code system is used for the calculation of scattered neutrons. The calculated results are compared with experimental ones measured by using indium (n, γ) reactions at the Nickel-Mirror Neutron Guide-Tube (NM NGT) attached to the KUR (Kyoto University Research Reactor, 5MW). Breakdown of flux distribution into two components and their depth dependency are clearly observed. Comparison is made between experiments and calculations of the total neutron flux distribution for the incident axis in the water phantom. A good agreement is obtained. Investigation is made of the contours of neutron intensities in 5 cm and 9 cm phantoms. They show similar intensity contours up to 15 mm radius from the beam incident surface. Calculation is also made of the axial neutron flux distributions in phantoms with different diameters. Very similar distributions are seen near the incident surface. (Nogami, K.)

  5. Application of digital signal-processing technique to delayed-neutron yield measurements on thermal-neutron induced fission of 237Np

    International Nuclear Information System (INIS)

    The measurement procedure based on the continuous thermal-neutron beam modulation with a mechanical chopper was developed for delayed-neutron yield measurement of the thermal-neutron induced fission of 237Np. The idea of the procedure is similar to that which is widely used in modern communications for the nonauthorized data access prevention. The data is modulated with predefined pattern before transmission to the public network and only the recipient that has the modulation pattern is able to demodulate it upon reception. For the thermal-neutron induced reaction applications, the thermal-neutron beam modulation pattern was used to demodulate the measured delayed-neutron intensity signals on the detector output resulting in nonzero output only for the detector signals correlated with the beam modulation pattern. A comparison of the method with the conventional measurement procedure was provided, and it was demonstrated that the cross-correlation procedure has special features making it superior over the conventional one when the measured value difference from the background is extremely small. Due to strong sensitivity of measurement procedure on the modulation pattern of the neutron beam, one can implement the modulation pattern of specific shape to separate the effect of the thermal part of the beam from the higher energy one in the most confident way in a particular experiment

  6. Studies on environmental pollution in Bangladesh using reactor based neutron activation analysis technique

    International Nuclear Information System (INIS)

    To assess the environmental degradation, the concentration of heavy metal such as chromium (Cr) in soil samples at various depths of existing tannery area of Hazaribagh, Dhaka, Bangladesh and the proposed tannery industrial area at Tatuljhora, Savar Dhaka, Bangladesh were analyzed by reactor based Neutron Activation Analysis (NAA) method. Arsenic levels in water, soil and herbal at different locations of Sonargaon Upzilla in Narayanganj district, Bangladesh were determined by the same method. The Cr-content at different depths of Hazaribagh area was found in the range of 38 to 33,500 ppm. Higher accumulations were observed in top soil that is above the US permissible level (20 to 85 ppm) except only one sample. The Cr-concentration in soils of Tatuljhora was in the range of 50.9 to 93.6 ppm, which is within the range of chromium background levels reported in worldwide (7 to 221 ppm). Arsenic detected in soil was in the range of 2.06-11.35 ppm. Few water samples contain arsenic above permissible level (0.05 ppm). Surprisingly, arsenic was also found considerably high in some herbals. The arsenic was not found in some herbal corresponding to the water samples where arsenic was not detected. Therefore, some Ayurvedic herbal medicine may be contaminated when they will be prepared with arsenic rich herbs. (author)

  7. Bending elasticity of saturated and monounsaturated phospholipid membranes studied by the neutron spin echo technique

    International Nuclear Information System (INIS)

    We have used neutron spin echo (NSE) spectroscopy to study the effect of bilayer thickness and monounsaturation (existence of a single double bond on one of the aliphatic chains) on the physical properties of unilamellar vesicles. The bending elasticity of saturated and monounsaturated phospholipid bilayers made of phospholipids with alkyl chain length ranging from 14 to 20 carbons was investigated. The bending elasticity κc of phosphatidylcholines (PCs) in the liquid crystalline (Lα) phase ranges from 0.38 x 10-19 J for 1,2-dimyristoyl-sn-glycero-3-phosphocholine to 0.64 x 10-19 J for 1,2-dieicosenoyl-sn-glycero-3-phosphocholine. It was confirmed that, contrary to the strong effect on the main transition temperature, the monounsaturation has a limited influence on the bending elasticity of lipid bilayers. In addition, when the area modulus KA varies little with chain unsaturation or length, the elastic ratios (κc/KA)1/2 of saturated and monounsaturated phospholipid bilayers varies linearly with lipid hydrophobic thickness d which agrees well with the theory of ideal fluid membranes.

  8. Determining neutron-capture cross sections via the surrogate reaction technique

    CERN Document Server

    Forssén, C; Escher, J; Hoffman, R D; Kelley, K

    2007-01-01

    Indirect methods play an important role in the determination of nuclear reaction cross sections that are hard to measure directly. In this paper we investigate the feasibility of using the so-called surrogate method to extract neutron-capture cross sections for low energy compound-nuclear reactions in spherical and near-spherical nuclei. We present the surrogate method and develop a statistical nuclear-reaction simulation to explore different approaches to utilize surrogate reaction data. We assess the success of each approach by comparing the extracted cross sections with a predetermined benchmark. In particular, we employ regional systematics of nuclear properties in the 34 <= Z <= 46 region to calculate (n,gamma) cross sections for a series of Zr isotopes, and to simulate a surrogate experiment and the extraction of the desired cross section. We identify one particular approach that may provide very useful estimates of the cross section, and we discuss some of the limitations of the method. General r...

  9. Neutron activation analysis techniques for identifying elemental status in Alzheimer's disease

    International Nuclear Information System (INIS)

    Brain tissue (hippocampus and cerebral cortex) from Alzheimer's disease and control individuals sampled from Eastern Canada and the United Kingdom were analyzed for Ag, Al, As, B, Br, Ca, Cd, Co, Cr, Cs, Cu, Fe, Hg, I, K, La, Mg, Mn, Mo, Ni, Rb, S, Sb, Sc, Se, Si, Sn, Sr, Ti, V and Zn. Neutron activation analysis (thermal and prompt gamma-ray) methods were used. Very highly significant differences (S**: probability less than 0.005) for both study areas were shown between Alzheimer's disease (AD) and control (C) individuals: AD>C for Al, Br, Ca and S, and AD< C for Se, V and Zn. Aluminium content of brain tissue ranged form 3.605 to 21.738 μg/g d.w. (AD) and 0.379 to 4.768 μg/g d.w. (C). No statistical evidence of aluminium accumulation with age was noted. Possible zinc deficiency (especially for hippocampal tissue), was observed with zinc ranges of 31.42 to 57.91 μg/g d.w. (AD) and 37.31 to 87.10 μg/g d.w. (C), for Alzheimer's disease patients. (author)

  10. Digital pulse-timing technique for the neutron detector array NEDA

    International Nuclear Information System (INIS)

    A new digital pulse-timing algorithm, to be used with the future neutron detector array NEDA, has been developed and tested. The time resolution of four 5 in. diameter photomultiplier tubes (XP4512, R4144, R11833-100, and ET9390-kb), coupled to a cylindrical 5 in. by 5 in. BC501A liquid scintillator detector was measured by employing digital sampling electronics and a constant fraction discriminator (CFD) algorithm. The zero crossing of the CFD algorithm was obtained with a cubic spline interpolation, which was continuous up to the second derivative. The performance of the algorithm was studied at sampling rates of 500 MS/s and 200 MS/s. The time resolution obtained with the digital electronics was compared to the values acquired with a standard analog CFD. The result of this comparison shows that the time resolution from the analog and the digital measurements at 500 MS/s and at 200 MS/s are within 15% for all the tested photomultiplier tubes

  11. Study of organohalogens in foodstuffs and environmental samples by neutron activation analysis and related techniques

    International Nuclear Information System (INIS)

    Pine needles and foodstuffs collected from Beijing, China, were analyzed by instrumental neutron activation analysis (INAA) combined with organic solvent extraction for total halogens, extractable organohalogens (EOX) and extractable persistent organohalogens (EPOX). The INAA detection limits are 50 ng, 8 ng and 3.5 ng for Cl, Br and I, respectively. The contents and distribution patterns of organohalogens in these samples are reported. EOCl accounted for 0.013-0.016% and 1.6-2.7% of the total chlorine in yogurt and apples, respectively, which suggested that chlorine in foodstuffs mainly existed as inorganic species and non-extractable organochlorines. EOCl contents in pine needles and foodstuffs were noticeably higher than those of EOBr and EOI. For pine needles, yogurt and apples, 1.6-34%, 23-58% and 29-35% of EOCl remained as extractable persistent organochlorine (EPOCl), respectively. Pine needle containing higher EOCl contents in chemical industrial and traffic hub areas indicated that chemical industries and exhaust emission from vehicle were the main sources of organochlorines in the Beijing's air. The relative proportions of the known organochlorines (such as HCHs, DDTs, chlordanes, heptachlor, HCB and PCBs) to the total EOCl and EPOCl were 0.04-1.6% and 0.7-21.5%, respectively, which implied that the identity of species of a major portion of the EOCl and EPOCl measured in pine needles was unknown. (author)

  12. Recently-developed neutron activation analysis techniques utilizing the University of California at Irvine TRIGA Mark I reactor

    International Nuclear Information System (INIS)

    The University of California at Irvine (UCI) 250 kW TRIGA Mark I reactor is used extensively for neutron activation analysis (NAA) studies. These particularly include basic technique studies and application studies in the fields of environmental pollution, crime investigation, archaeology, oceanography, and geochemistry. In recent NAA studies at UCI, a number of techniques have been developed which considerably improve the usefulness of such a research reactor for NAA work, and which should be of interest and use to others. Six of these techniques will be described in further detail in the full paper. They are as follows: development and use of (1) an automated high-precision rapid transfer system for instrumental NAA measurements with induced activities having half lives as short as 0.5 second, (2) an automated measurement system and computer program for making accurate dead-time corrections under conditions where the Ge(Li) spectrometer deadtime is changing rapidly during the counting period, (3) a technique to minimize the loss of mercury from samples during reactor irradiation via the use of dry-ice-packed, vented TRIGA rotary rack tubes, (4) a technique for compacting powdered samples, by pre-irradiation treatment with a solution of paraffin in carbon disulfide, to provide reproducible irradiation and counting geometries, (5) a method utilizing hydrated antimony pentoxide (HAP) as a pre-irradiation treatment material for removal of sodium from aqueous and wet-ashed samples, and (6) a computerized system for predicting in advance of activation, from approximate known elemental compositions, the total counting rate, deadtime, spectrum shape, principal photopeaks, and approximate actual lower limits of instrumental NAA detection of designated elements for any selected irradiation and decay times. (author)

  13. Amino acids analysis using grouping and parceling of neutrons cross sections techniques; Analise de aminoacidos atraves das tecnicas do agrupamento e parcelamento de secoes de choque para neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Voi, Dante Luiz Voi [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil); Rocha, Helio Fenandes da [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Puericultura e Pediatria Martagao Gesteira

    2002-07-01

    Amino acids used in parenteral administration in hospital patients with special importance in nutritional applications were analyzed to compare with the manufactory data. Individual amino acid samples of phenylalanine, cysteine, methionine, tyrosine and threonine were measured with the neutron crystal spectrometer installed at the J-9 irradiation channel of the 1 kW Argonaut Reactor of the Instituto de Engenharia Nuclear (IEN). Gold and D{sub 2}O high purity samples were used for the experimental system calibration. Neutron cross section values were calculated from chemical composition, conformation and molecular structure analysis of the materials. Literature data were manipulated by parceling and grouping neutron cross sections. (author)

  14. What can we learn from the neutron clinical experience for improving ion-beam techniques and high-LET patient selection?

    International Nuclear Information System (INIS)

    .e., moving from neutrons to 12C ions and from photons to protons, respectively). An important area of research involves developing criteria to identify specific patients suitable for high-LET radiation. One promising technique is to measure the RBE of the cancer cell population in vitro mainly in head and neck tumors. Modern molecular imaging allows the identification of hypoxic or proliferative regions in the tumor. Special MRI examinations are also able to identify hypoxic regions. A promising predictive test recently initiated, is the study of non-repairable double strand breaks but the utility of the technique needs to be confirmed. The extensive experience with fast neutron therapy can greatly assist the transition to high-LET charged-particle therapy.

  15. Domain wall motion and magnetization reversal processes in a FeSi picture frame single crystal studied by the time-dependent neutron depolarization technique

    International Nuclear Information System (INIS)

    The three dimensional neutron depolarization technique, which gives detailed information about the static properties of ferromagnetic materials, has been extended to a method by means of which the time dependence of magnetic phenomena can be studied. The measurement of the neutron depolarization against time is made possible by applying a periodical magnetic field on the investigated specimen and by continuous sampling of the transmitted neutron intensity in time channels, which are started synchronously with the applied field. The technique has been used in the study of the magnetic domain structure at room temperature of a (010) [001] picture frame FeSi single crystal (3.5 wt.% Si) with outer dimensions of (15 x 10 x 0.26) mm and a frame width of 2.78 mm. (Auth.)

  16. Standard Test Method for Measuring Neutron Fluence and Average Energy from 3H(d,n)4He Neutron Generators by Radioactivation Techniques 1

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This test method covers a general procedure for the measurement of the fast-neutron fluence rate produced by neutron generators utilizing the 3H(d,n)4He reaction. Neutrons so produced are usually referred to as 14-MeV neutrons, but range in energy depending on a number of factors. This test method does not adequately cover fusion sources where the velocity of the plasma may be an important consideration. 1.2 This test method uses threshold activation reactions to determine the average energy of the neutrons and the neutron fluence at that energy. At least three activities, chosen from an appropriate set of dosimetry reactions, are required to characterize the average energy and fluence. The required activities are typically measured by gamma ray spectroscopy. 1.3 The measurement of reaction products in their metastable states is not covered. If the metastable state decays to the ground state, the ground state reaction may be used. 1.4 The values stated in SI units are to be regarded as standard. No oth...

  17. Neutron beam applications; development of texture measuring technique using 1-dimensional PSD

    Energy Technology Data Exchange (ETDEWEB)

    Park, No Jin; Lee, Moon Kyu; Joung, Tae Won; Lee, In Sung [Kumoh National University of Technology, Kumi (Korea)

    2002-03-01

    The new developed materials have often a low crystal symmetry or/and multi-phase state. Because the diffraction patterns of those materials are very complex and some peaks are overlapped, the measured pole figures with a conventional detector (0-dimensional detector) are not sufficient to use for the texture analysis. And also the widely broaden diffraction patterns caused by sever deformation, can only measured with lots of measuring errors using 0-dimensional detector. In this study the 1-dimensional and 2-dimensional position sensitive detector(PSD) is used such pattern to analyse. With PSD the more accurate pole figures can be measured, and the texture analysis, the estimation of the properties are determined more precisely. The measurement using PSD needs special technique for the analysis of the measured pattern. In this study the measuring and analysing technique is developed and compared with the conventional detector. 11 refs., 92 figs., 21 tabs. (Author)

  18. Measurement/Evaluation Techniques and Nuclear Data Associated with Fission of 239Pu by Fission Spectrum Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Baisden, P; Bauge, E; Ferguson, J; Gilliam, D; Granier, T; Jeanloz, R; McMillan, C; Robertson, D; Thompson, P; Verdon, C; Wilkerson, C; Young, P

    2010-03-16

    This Panel was chartered to review and assess new evaluations of work on fission product data, as well as the evaluation process used by the two U.S. nuclear weapons physics laboratories. The work focuses on fission product yields resulting from fission spectrum neutrons incident on plutonium, and includes data from measurements that had not been previously published as well as new or revised fission product cumulative yield data, and related quantities such as Q values and R values. This report documents the Panel's assessment of the work presented by Los Alamos National Laboratory (LANL) and Lawrence Livermore National Laboratory (LLNL). Based on the work presented we have seven key observations: (1) Experiments conducted in the 1970s at LANL, some of which were performed in association with a larger, NIST-led, program, have recently been documented. A preliminary assessment of this work, which will be referred to in this document as ILRR-LANL, shows it to be technically sound. (2) LLNL has done a thorough, unbiased review and evaluation of the available literature and is in the process of incorporating the previously unavailable LANL data into its evaluation of key fission product yields. The results of the LLNL effort, which includes a preliminary evaluation of the ILRR-LANL data, have been documented. (3) LANL has also conducted an evaluation of fission product yields for fission spectrum neutrons on plutonium including a meta-analysis of benchmark data as part of a planned upgrade to the ENDF/B compilation. We found that the approach of using meta-analysis provides valuable additional insight for evaluating the sparse data sets involved in this assessment. (4) Both laboratories have provided convincing evidence for energy dependence in the fission product yield of {sup 147}Nd produced from the bombardment of {sup 239}Pu with fission spectrum neutrons over an incident neutron energy range of 0.2 to 1.9 MeV. (5) Consistent, complete, and explicit treatment

  19. Proposal of requirements for performance in Brazil for systems of external individual monitoring for neutrons applying the TLD-albedo technique

    International Nuclear Information System (INIS)

    This work presents a criteria and conditions proposal for the regulations in Brazil of individual monitoring systems for neutrons applying the albedo technique with thermoluminescent detectors. Tests are proposed for the characterization performance of the system based on the Regulation ISO 21909 and on the experience of the authors

  20. Measurement of the magnetic moment of the 2$^{+}$ state in neutron-rich radioactive $^{72,74}$Zn using the transient field technique in inverse kinematics

    CERN Multimedia

    Kruecken, R; Speidel, K; Voulot, D; Neyens, G; Gernhaeuser, R A; Fraile prieto, L M; Leske, J

    We propose to measure the sign and magnitude of the g-factors of the first 2$^{+}$ states in radioactive neutron-rich $^{72,74}$Zn applying the transient field (TF) technique in inverse kinematics. The result of this experiment will allow to probe the $\

  1. Water utilization of vegetables grown under plastic greenhouse conditions in Ankara using neutron probe technique

    International Nuclear Information System (INIS)

    In order to find suitable varieties of tomato, pepper and cucumber for plastic greenhouse conditions in Ankara and ensure both higher yields and lower NO3 leaching greenhouse experiments were conducted for three years. In the first year (2001) of the experiment four different varieties from each vegetable, namely, Tomato (Ecem F1, 9920 F1, 2116 F1 and Yazg1 F1), Cucumber (Hizir F1 , Rapido, Hana, and Luna) and Pepper (1245 F1, 730 F1, Serademre 8 and 710 F1) had been grown in the plastic greenhouse using drip irrigation-fertilization system. Yazg1 F1 variety for tomato, Hizir F1 variety for cucumber and Serademre 8 variety for pepper were chosen to be suitable varieties to grow in the plastic greenhouse conditions in Ankara. One access tube in each N3 and N0 treatment plots of tomato, cucumber and pepper in 2002 and 2003 experiments were installed for the soil moisture determinations at 30, 60 and 90 cm depths. Readings with the neutron probe were taken before planting and after harvest for the water consumption calculations using the water balance approach and the WUE was calculated on the basis of the ratio of dry matter weight to the amount of water consumed. Tensiometer and suction cups were installed at 15, 30, 45 and 60 cm depths only to N1, N2 and N3 treatments plots of each vegetable in 2002 and 2003. Tensiometer readings were taken just before irrigation. Also, soil solution samples from suction cups were taken at final harvest and NO3 determinations were done with RQFLEX nitrate test strips. Significantly higher yields and WUE values were obtained when the same amount of N fertilizer is applied through fertigation compared to the treatment where N fertilizer applied to the soil then drip irrigated. The nitrate concentrations of the soil solution increased as the N rates increased and no NO3 had been found in the soil solution taken from 75 cm soil depth, indicating that no leaching of N fertilizer occurred beyond 75 cm soil depth. (author)

  2. Study of organohalogens in foodstuffs and environmental Samples by neutron activation analysis and related techniques

    International Nuclear Information System (INIS)

    Full text: Organic halogens, especially organochlorinated compounds, which come from extensive use of pesticides and herbicides, and discharge of wastewater from bleaching of pulp and wastewater treatment, have caused world-wide contamination and drawn great concern. Polychlorinated biphenyls, hexachlorobenzene, organochlorinated pesticides and their metaborites are well-known pollutants in the environment because of their persistence, bioaccumulation and potential environmental hazardous effect. Recently, a significant number of studies indicated that traditional analytical methods such as gas chromatography and gas chromatography- mass spectrometry could only provide information about the known organochlorines, which contributed to less than 1-20 % of total amount of extractable organochlorinated compounds in samples and therefore the results couldn't reflect their actual contamination levels. Instrumental neutron activation analysis is the only analytical method currently available for simultaneously determining various extractable organohalogens. In this work an INAA method combined with organic solvent extraction for determination of extractable organohalogens (EOX) in milk and pine needle collected from various regions of China has been established. The detection limits are 50 ng, 8 ng and 3.5 ng for Cl, Br and I, respectively. The concentrations of EOX in the samples are decreasing in the order of EOCl >> EOBr > EOI. The average concentration of EOCl in milk is 4.44 μg/g expressed as fat weight basis, with the highest 17.6 μg/g on fat weight basis from the developed regions in China. The mean concentrations of total HCH and DDT are 0.038 μg/g and 0.046 μg/g, respectively. Organochlorine pesticides only account for 1.6% of the EOCl, indicating the very high proportion of the unknown EOCl in the milk samples. The concentrations of EOCl, EOBr and EOI in pine needles are 0.5-6.0, 0.06-0.54 and 0.013- 0.4 μg/g dry weight, respectively. 5 to 38 % of EOCl

  3. Asymmetric distribution of cone-shaped lipids in a highly curved bilayer revealed by a small angle neutron scattering technique

    International Nuclear Information System (INIS)

    We have investigated the lipid sorting in a binary small unilamellar vesicle (SUV) composed of cone-shaped (1,2-dihexanoyl-sn-glycero-3-phosphocholine: DHPC) and cylinder-shaped (1,2-dipalmitoyl-sn-glycero-3-phosphocholine: DPPC) lipids. In order to reveal the lipid sorting we adopted a contrast matching technique of small angle neutron scattering (SANS), which extracts the distribution of deuterated lipids in the bilayer quantitatively without steric modification of lipids as in fluorescence probe techniques. First the SANS profile of protonated SUVs at a film contrast condition showed that SUVs have a spherical shape with an inner radius of 190 A and a bilayer thickness of 40 A. The SANS profile of deuterated SUVs at a contrast matching condition showed a characteristic scattering profile, indicating an asymmetric distribution of cone-shaped lipids in the bilayer. The characteristic profile was described well by a spherical bilayer model. The fitting revealed that most DHPC molecules are localized in the outer leaflet. Thus the shape of the lipid is strongly coupled with the membrane curvature. We compared the obtained asymmetric distribution of the cone-shaped lipids in the bilayer with the theoretical prediction based on the curvature energy model.

  4. Residual stress distribution in austenitic stainless steel pipe butt-welded joint measured by neutron diffraction technique

    International Nuclear Information System (INIS)

    Residual stress is inevitable consequence of welding or manufacturing process, which might greatly affect propagation of high-cycle fatigue or SCC crack. In order to evaluate damages due to the crack, it is required to estimate residual stress and to reflect them to the evaluation process as well. The magnitude and distribution of residual stress greatly depend on the individual process of welding or manufacturing, while the accuracy of prediction or measurement is still insufficient. This paper reports the result of residual stress measurement of butt-welded pipe made of austenitic stainless steel. It also intended to improve prediction and measurement techniques concerning to residual stress. The measurement was conducted by neutron diffraction technique employing the diffractometer for residual stress analysis developed by Japan Atomic Energy Agency. The measured results showed typical characteristics of butt-welded pipe both in decline of stress along axial direction and in radial distribution of bending due to axial stress. The measured result agreed qualitatively with the result predicted by the finite element analysis. A quantitative comparison between measured result and analysis showed a shift of the measured stress toward higher tensile. The measured result was also compared with the results by X-ray diffraction and strain-gauge methods to grasp the distinctive results of the methods. (author)

  5. Biomonitoring of atmospheric pollution (with emphasis on trace elements) - BioMap II. Proceedings of an international workshop

    International Nuclear Information System (INIS)

    Certain types of organisms integrate pollution over time, reducing the need for continuous chemical monitoring, thus avoiding the difficulty of interpreting 'snapshot' measurements and offering the potential of retrospective monitoring. Such organisms enrich the substance to be determined so that the analytical accessibility is improved and the measurement uncertainty reduced. By observing and measuring the changes in an appropriately selected organism, a conclusion as to the kind of pollution, its source, and its intensity can be drawn. The IAEA is making concerted efforts to promote the practical use of nuclear and related analytical techniques in studies of non-radioactive environmental pollutants that may impact on human health, and one of the main emphasis is on studying air contaminants. The IAEA has been systematically supporting biomonitoring atmospheric pollution for 10 years in the framework of its project on Environmental Pollution Monitoring and Research Using Nuclear and Related Analytical Techniques. The objective of this project is to identify the source and evaluate the fate of key non-radioactive environmental contaminants and provide the basis for improved health for human populations. The project has been implemented through a Coordinated Research Project on Validation and Application of Plants as Biomonitors of Trace Element Atmospheric Pollution Analysed by Nuclear and Related Techniques, several technical co-operation projects, and some dedicated analytical quality control activities. Within the scope of these efforts, the Second International Workshop on Biomonitoring of Atmospheric Pollution (with Emphasis on Trace Elements) - BioMAP, was organized as a follow-up to the 1997 BioMAP workshop held in Lisbon, Portugal. The proceedings of the first workshop were published in IAEA-TECDOC-1152. The second workshop was held in Praia da Vitoria, Azores Islands, Portugal, from 28 August to 3 September 2000. It was organized in co-operation with the

  6. Biomonitoring of Occupational Exposure to Total Arsenic and Total Mercury in Urine of Goldmine Workers in Southwestern Ghana

    Directory of Open Access Journals (Sweden)

    Rex Gyeabour Abrefah

    2011-06-01

    Full Text Available Biomonitoring of total arsenic and total mercury in the urine of goldmine workers in south-western Ghana due to occupational exposure was conducted to determine whether occupational exposure substantially contributes to their overall exposure to arsenic and mercury. The urine was collected after 2-day abstinence from sea foods by the workers and from those with no dental amalgam fillings. Total arsenic and total mercury were simultaneously determined by instrumental neutron activation analysis (INAA. After 1-hour irradiation of the urine in Ghana's miniature neutron source reactor (GHARR-1 to induce 76As and 197Hg radionuclides through nuclear reactions 75As(n, γ76As, and 196Hg(n, γ197Hg, the γ-radiation intensity of the induced 76As and 197Hg radionuclides were measured by γ-spectrometry. The validity of the INAA technique for As and Hg determination was checked by analyses of NIST SRM 3103a (As standard solution and NIST SRM 3133 (Hg standard solution, respectively. The mean mass fractions of arsenic in the urine are 6.76 µg/L ± 1.43, 7.78 µg/L ± 1.33, 8.03 µg/L ± 1.75, 10.44 µg/L ± 1.88, and 14.75 µg/L ± 1.62 for workers in offices 10 km from the mine, 2 km from the mine, 0.5 km from the mine, casual mine workers, and gold ore processing workers, respectively. The levels of arsenic in the urine are all within the 5 to 40 µg As L-1 day-1 normal range for excretion of arsenic. The observed mass fraction of As was higher in high exposure workers. The mean mass fraction of Hg in the urine are 0.36 µg/L ± 0.11, 0.47 µg/L ± 0.12, 0.51 µg/L ± 0.16, 0.57 µg/L ± 0.14, and 0.56 µg/L ± 0.21 for workers in offices 10 km from the mine, 2 km from the mine, 0.5 km from the mine, casual mine workers, and gold ore processing workers, respectively. The high Hg exposed workers engage in small scale gold mining using mercury. The exposure of the different categories of workers to both total arsenic and total mercury are safe.

  7. Substoichiometric radiochemical separation and their application to neutron activation analysis technique

    International Nuclear Information System (INIS)

    Radiochemistry is the chemistry of substances which are detected by their nuclear radiations. The first radiochemical separation was used by Marie and Pierre Curie. The present paper discusses the concept of purity and the importance of various radiochemical separation methods such as precipitation, volatilization, high vacuum distillation, ring oven technique, ion exchange, solvent extraction, etc. NAA can be carried out by comparator or absolute method. Comparator method can be performed by radiochemical or instrumental technique. Radiochemical separation for NAA requires that the final product must be in well-defined chemical form, so as to obtain correct chemical yield. The chemical yield determination is time-consuming and important, especially when the product of activation has a short half-life. Ruzika and Star/proposed a substoichiometric procedure which uses subequivalent amount of the reagent corresponding to the amount of carrier added. If the carrier and reagent added to the sample and standard are the same, and the same fraction is isolated free from other activation products, the chemical yield determination is not required. The process becomes quantitative and time saving. The present paper discusses some new, rapid and selective method developed for the substoichiometric radiochemical separation and estimation of some elements

  8. Elemental activation analysis with decay and prompt gamma ray techniques, using isotopic neutron sources and a nuclear research reactor. Part of a coordinated programme on nuclear-based techniques in geology and mineral prospecting

    International Nuclear Information System (INIS)

    This is to review the research activities carried out through the IAEA research Project 1697/RB ''Elemental activation analysis with decay and prompt gamma ray techniques, using isotopic neutron sources and the nuclear research reactor. The programme of work includes: a) Development of decay and prompt gamma ray activation techniques for mineral exploration. b) Development of epithermal NAA in addition to thermal NAA especially for gold ore. c) Development of non-destructive insitu elemental analysis with decay and prompt gamma ray techniques using isotopic neutron sources. A joint programme has been established with the Egyptian Geological Surrey and Mining Authority for using nuclear techniques in evaluating gold prospects of several ancient gold mines and investigating several tin-tantalum deposits, which were discovered over the last few years. Two sources of neutrons were used for irradiation, one of the dry channels of the two megawatts research reactor, ET-RR-1 for laboratory studies, and a Pu-Be neutron source in paraffin assembly for possible insitu work

  9. Determination of Methylmercury Traces in Biological Matrix: Chemical Extraction and Nuclear Quantification with the Neutron Activation Analysis Technique

    International Nuclear Information System (INIS)

    Mercury is present in the environment as a result of the human and natural activities.The total amount of Hg present in the biosphere has been incremented three times since the industrial era, and now it is affecting in a global sense all the ecosystem.One of the main entrance of Hg in the human diet is the consumption of fish and other marine creatures.Most of the ingested Hg is mono methylmercury (MeHg), which is one of the most toxic forms in which this element could be found because it crosses membranes.Since the toxicity levels are low, the determination of concentrations of total Hg and Me Hg require very careful sampling, sample conditioning and analytical procedures to prevent either losses or contamination, or the degradation of the Hg species.In this work, we implemented a chemical Me Hg extraction procedure, using a ionic exchange resin, with three different types of fish tissue: muscle, liver and hepato pancreas.After Me Hg extraction, the determination and quantification was made by Instrumental Neutron Activation Analysis, by measuring the 197 Au, y el 203 Tl deexcitation s, created through the radioactive decay of the isotopes 197 Hg y 203 Hg.The influence of several parameters on the overall extraction process, such as velocity of passage through the ionic exchange column and the acid concentration used in the extraction was evaluated.Regarding the INAA determinations, a choice was made for the irradiation, decay and counting times, neutron and gamma doses, and the counting geometry The detection limit found for this technique (dry weight) is 140 pg MeHg/g. The Hg contents of the muscle samples were measured with the 279 keV emission of the product of the 202 Hg(n,g)203 Hg reaction, with a recovery of (100 ± 13)%. Liver and Hepato pancreas samples were measured with the 77 keV gamma emission of the 197 Hg, checking this result with the 67 y 69 keV X emissions from the same isotope.The liver samples needed an extra vacuum filtering process during

  10. Production of fast monoenergetic neutrons by charged particle reactions among the hydrogen isotopes. Source properties, experimental techniques and limitations of the data

    International Nuclear Information System (INIS)

    All five reactions 2H(d,n)3He, 1H(t,n)3He, 3H(p,n)3He, 3H(d,n)4He and 2H(t,n)4He are discussed with special emphasis on recent developments and on the higher neutron energy range up to 40 MeV. It is discussed how inclusion of recent data will change previous evaluations of the p-T system at lower energies. Breakup data of all reactions are collected. Experimental techniques and uncertainties of neutron source property measurements are discussed and recommendations for future work are given. (author)

  11. $\\beta$-decay study of neutron-rich Tl, Pb, and Bi by means of the pulsed-release technique and resonant laser ionisation

    CERN Multimedia

    Lettry, J

    2002-01-01

    It is proposed to study new neutron-rich nuclei around the Z = 82 magic shell closure, with major relevance for understanding the evolution of nuclear structure at extreme isospin values. Following the IS354 experiment, $\\beta$-decay studies of neutron-rich thallium, lead and bismuth isotopes will be performed for 215 $\\leqslant$ A $\\leqslant$ 219. To this purpose the pulsed-release technique, which was pioneered at ISOLDE, will be optimised. It will be complemented with the higher element selectivity that can be obtained by the unique features of resonant laser ionisation, available at ISOLDE from the RILIS source.

  12. Measurement of 232Th(, ) and 232Th(, 2) cross-sections at neutron energies of 13.5, 15.5 and 17.28 MeV using neutron activation techniques

    Indian Academy of Sciences (India)

    Sadhana Mukerji; H Naik; S V Suryanarayana; S Chachara; B S Shivashankar; V Mulik; Rita Crasta; Sudipta Samanta; B K Nayak; A Saxena; S C Sharma; P V Bhagwat; K K Rasheed; R N Jindal; S Ganesan; A K Mohanty; A Goswami; P D Krishnani

    2012-08-01

    The 232Th(, ) reaction cross-section at average neutron energies of 13.5, 15.5 and 17.28 MeV from the 7Li(, ) reaction has been determined for the first time using activation and off-line -ray spectrometric technique. The 232Th(, 2) cross-section at 17.28 MeV neutron energy has also been determined using the same technique. The experimentally determined 232Th(, ) and 232Th(, 2) reaction cross-sections from the present work were compared with the evaluated data of ENDF/BVII and JENDL-4.0 and were found to be in good agreement. The present data, along with literature data in a wide range of neutron energies, were interpreted in terms of competition between 232Th(, ), (, ), (, ) and (, ) reaction channels. The 232Th(, ) and 232Th(, 2) reaction cross-sections were also calculated theoretically using the TALYS 1.2 computer code and were found to be in good agreement with the experimental data from the present work but were slightly higher than the literature data at lower neutron energies.

  13. Traffic contribution to air pollution in urban street canyons: Integrated application of the OSPM, moss biomonitoring and spectral analysis

    Science.gov (United States)

    Lazić, Lazar; Urošević, Mira Aničić; Mijić, Zoran; Vuković, Gordana; Ilić, Luka

    2016-09-01

    To investigate the air pollutant distribution within the ambient of urban street canyon, Operational Street Pollution Model (OSPM) was used to predict hourly content of NOX, NO, NO2, O3, CO, BNZ and PM10. The study was performed in five street canyons in Belgrade (Serbia) during 10-week summer period. The model receptors were located on each side of street canyons at 4 m, 8 m and 16 m height. To monitor airborne trace element content, the moss bag biomonitors were simultaneously exposed with the model receptors at two heights-4 m and 16 m. The results of both methods, modelling and biomonitoring, showed significantly decreasing trend of the air pollutants with height. The results indirectly demonstrate that biomonitoring, i.e., moss bag technique could be a valuable tool to verify model performance. In addition, spectral analysis was applied to investigate weekly variation of the daily background and modelled data set. Typical periodicities and weekend effect, caused by anthropogenic influences, have been identified.

  14. [Animal biomonitoring and micropollutants in public health--review].

    Science.gov (United States)

    Rombolà, Pasquale; Battisti, Sabrina; Scaramozzino, Paola

    2012-01-01

    The aim of the present review is to provide a picture of the current knowledge on animal biomonitoring and on the link between pollution and Public Health. There are various reasons leading to this road: the need of early detection of industrial pollutants, especially micropollutants that have adverse effects in very low concentrations: it is important to disclose the presence of these compounds directly or through certain molecular biomarkers in living organisms rather than in the natural environment, where they are often below the detection threshold; the need to optimize the allocation of resources: some experiences of biomonitoring carried out in wild animals may be useful in the identification of pollution sources; however, biomonitoring of domestic animals appears to be more feasable and effective, because they share with humans the exposure to pollutants. Nowadays, professionals of different disciplines such as doctors and biologists do not share a common set of terms and definitions in animal biomonitoring: this review wants to give a contribution in the consolidation of the current knowledge under a common language. PMID:23139184

  15. Novel Technique of Active Biomonitoring Introduced in the Czech Republic: Bioaccumulation of Atmospheric Trace Metals in two moss species / Nová Metoda Aktivního Biomonitoringu Zavedená V České Republice: Bioakumulace Stopových Kovů V Atmosféře U Dvou Druhů Mechů

    Directory of Open Access Journals (Sweden)

    Motyka Oldřich

    2011-09-01

    Full Text Available Za účelem validace byla pro biomonitoring v průmyslem ovlivněném regionu Ostravska použita metoda, která dosud v České republice nebyla aplikována. Transplantáty dvou druhů mechů Hylocomium splendens a Pleurozium schreberi byly vystaveny atmosférickému znečištění pomocí metody “irrigated moss bag” ve výšce jak 1 m, tak 2 m nad zemí. Vzorky byly poté analyzovány za účelem zjištění koncentrace stopových prvků Al, As, Cd, Cr, Cu, Fe, Hg, Pb, V a Zn. Celkový průběh bioakumulace ukazuje, že je Hylocomium splendens pro biomonitoring vhodnější, stejně tak jako výška 2 m nad zemí.

  16. Chromium Fractions Changes Compared With Total-Cr As Determined by Neutron Activation Analysis Technique

    International Nuclear Information System (INIS)

    Fifteen soil samples were chosen from different locations (five different locations at north greater Cairo, Egypt to represent different soils (alluvial and sandy) as well as different source of contaminated wastewater (sewage and industrial effluent). Using sequential extraction technique (extracting the soil with different solutions, which is designed to separate metal fractions), Cr was separated into six operationally defined fractions water soluble, exchangeable, carbonate bound, Fe-Mn oxides bound, organic bound and residual fractions. Result of soil total-Cr indicated the serious accumulation of Cr in soils subjected to prolonged irrigation with contaminated wastewater. As it could seen, total-Cr in the tested contaminated soils exceeds the permissible levels (75-100)ppm Cr by several order of magnitude particularly at the surface and subsurface layers. The highest accumulation of total Cr down to depth 60 cm was observed in case of soil E. Data showed that values of total Cr determined by NAA method were always higher than the relevant values determined either by AAS or those calculated after the sequential extraction method. T-test analysis showed the significant difference between NAA and either AAS or sequential extraction methods. Although T-test analysis showed that were significant differences between total content in soils as determined by destructive (AAS or SUM) and non-destructive (NAA) analytical techniques however, strong liner relation between NAA and other tested methods was obtained. Chromium distribution between different extractants shows that the greatest amounts are found in the residual and Occluded in Fe and Mn-Oxides fractions followed by carbonate or organic fractions. In most cases the proportion of all tested Cr-forms has increased in contaminated soil layers with higher enrichment in organically bound Cr, occluded in Fe and Mn oxides, carbonate exchangeable and soluble fractions. Results indicate that soil properties have a

  17. The associated proton monitoring technique study of D-D source neutron yields at the large angle

    International Nuclear Information System (INIS)

    By selecting a two-direction target chamber and a three-direction target chamber, neutron yields from D-D reaction were monitored at K-400 accelerator with associated proton method. Detectors were put at the direction of 90 degree, 135 degree and 178.2 degree refer to D+ beam, from which the associated proton spectrum and the absolute neutron yields were obtained, the accurate experimental condition for neutron yields monitoring was determined, and finally neutron yields monitoring at the large angle (178.2 degree) was confirmed. Experimental results and it's accuracy were also analyzed and discussed. (authors)

  18. A study on the technique of a new type of neutron detector prototype with a high detection efficiency

    International Nuclear Information System (INIS)

    Based on that the neutron detectors used now have some disadvantages such as low detection efficiency, long response time, etc, studied the new development of neutron detection a new type of neutron detector prototype using plastic scintillator BC454 and inorganic scintillator BGO as the detection medium was proposed. Simulation of its detection efficiency and other parameters was done using Monte Carlo general code MCNP (Version 4B). This new kind of portable neutron detector with high detection efficiency and sensitivity is strongly needed. (authors)

  19. Investigating Early/Middle Bronze Age copper and bronze axes by micro X-ray fluorescence spectrometry and neutron imaging techniques

    Science.gov (United States)

    Figueiredo, Elin; Pereira, Marco A. Stanojev; Lopes, Filipa; Marques, José G.; Santos, Joana P.; Araújo, M. Fátima; Silva, Rui J. C.; Senna-Martinez, João C.

    2016-08-01

    Micro X-ray fluorescence (micro-XRF) analysis and neutron imaging techniques, namely 2D radiography and 3D tomography, have been applied for the study of four metal axes from the Early/Middle Bronze Age in Western Iberia, a period characterized by a metallurgical change in the use of copper to bronze. Micro-XRF analysis has shown that one of the axes was produced in copper with some arsenic while the other three were produced in a copper-tin alloy (bronze) with variable tin contents and some arsenic and lead. Neutron radiography and tomography were applied to study internal heterogeneities of the axes in a non-invasive way since the specificities of neutron interaction with matter allow a suitable penetration of these relatively thick copper-based objects when compared to the use of a conventional X-ray radiography. Neutron imaging allowed the visualization of internal fissures and pores and the evaluation of their distribution, size and shape. Relevant information for the reconstruction of ancient manufacturing techniques was gathered, revealing that one ax was produced with the mold in an angle of ≈ 25°, probably to facilitate gas escape during metal pouring. Also, information regarding physical weaknesses of the axes was collected, providing relevant data for their conservation. The combination of these non-destructive techniques allowed the evaluation of the metal composition and the internal structure of the axes. Micro-XRF allowed the distinction among copper and bronze axes, and provided data about the composition of early bronzes for which data is scarce. The neutron imaging study allowed for the first time the visualization of internal heterogeneities in early bronze axes, namely pores and large voids, providing relevant information for the reconstruction of ancient manufacturing techniques and raising pertinent information regarding physical weaknesses of these types of objects.

  20. The ESA Topical Team 'Biomonitors': Monitoring for the protection of environments from human activities

    Science.gov (United States)

    Rettberg, P.; Esa Tt Biomonitors

    The overall aim of the ESA Topical Team Biomonitors was to identify and summarize ongoing and planned ground based biotechnological research activities on environmental monitoring that will also become important in space research within the ESA Microgravity Applications Promotion Program Monitoring the environment for compounds and factors of concern plays an important role in defining and managing the risks to environments and artificial ecosystems on other planets resulting from chemical and biological contaminations but also gains increasing attention for a variety of terrestrial applications Especially the development of biosensors and the identification of biomarkers for the qualitative and or quantitative registration of deleterious effects is a promising approach for new tools complementary to currently available physical and chemical monitoring techniques Another very important field of concern was the fast identification and assessment of the microbial bioburden On one hand this is necessary for the long-term securing of human health and performance in a confined environment like the ISS or in a future extraterrestrial habitat On the other hand this is necessary for the development and application of adequate cleaning and sterilization measures of spacecraft for planetary protection reasons especially for already scheduled lander missions to Mars Acknowledgements The ESA Topical Team Biomonitors was financed by ESTEC Contract Nr 137989 99 NL JS The authors thank R Binot for fruitful discussions on the future of biotechnology in