WorldWideScience

Sample records for biomonitoring technique neutron

  1. 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

  2. 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

  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.

  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. 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...

  11. 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)

  12. 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

  13. 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...

  14. 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...

  15. 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 ...

  16. 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)

  17. 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.

  18. 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...

  19. 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...

  20. 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)

  1. 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)

  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. 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)

  4. 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

  5. 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.

  6. Characterization of the Etna volcanic emissions through an active biomonitoring technique (moss-bags): part 2--morphological and mineralogical features.

    Science.gov (United States)

    Calabrese, S; D'Alessandro, W

    2015-01-01

    Volcanic emissions were studied at Mount Etna (Italy) by using moss-bags technique. Mosses were exposed around the volcano at different distances from the active vents to evaluate the impact of volcanic emissions in the atmosphere. Morphology and mineralogy of volcanic particulate intercepted by mosses were investigated using scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS). Particles emitted during passive degassing activity from the two active vents, Bocca Nuova and North East Crater (BNC and NEC), were identified as silicates, sulfates and halide compounds. In addition to volcanic particles, we found evidences also of geogenic, anthropogenic and marine spray input. The study has shown the robustness of this active biomonitoring technique to collect particles, very useful in active volcanic areas characterized by continuous degassing and often not easily accessible to apply conventional sampling techniques.

  7. 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

  8. 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)

  9. 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)

  10. 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)

  11. 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)

  12. 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

  13. 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.

  14. 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

  15. 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.)

  16. 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)

  17. 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

  18. 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.

  19. 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

  20. Elements of slow-neutron scattering basics, techniques, and applications

    CERN Document Server

    Carpenter, J M

    2015-01-01

    Providing a comprehensive and up-to-date introduction to the theory and applications of slow-neutron scattering, this detailed book equips readers with the fundamental principles of neutron studies, including the background and evolving development of neutron sources, facility design, neutron scattering instrumentation and techniques, and applications in materials phenomena. Drawing on the authors' extensive experience in this field, this text explores the implications of slow-neutron research in greater depth and breadth than ever before in an accessible yet rigorous manner suitable for both students and researchers in the fields of physics, biology, and materials engineering. Through pedagogical examples and in-depth discussion, readers will be able to grasp the full scope of the field of neutron scattering, from theoretical background through to practical, scientific applications.

  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. 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.

  3. Investigations on landmine detection by neutron-based techniques.

    Science.gov (United States)

    Csikai, J; Dóczi, R; Király, 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 1m(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 6.13MeV gamma-ray emitted in the (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.

  4. 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...

  5. Identification of Fissionable Materials Using the Tagged Neutron Technique

    Energy Technology Data Exchange (ETDEWEB)

    R.P. Keegan, J.P. Hurley, J.R. Tinsley, R. Trainham

    2009-06-30

    This summary describes experiments to detect and identify fissionable materials using the tagged neutron technique. The objective of this work is to enhance homeland security capability to find fissionable material that may be smuggled inside shipping boxes, containers, or vehicles. The technique distinguishes depleted uranium from lead, steel, and tungsten. Future work involves optimizing the technique to increase the count rate by many orders of magnitude and to build in the additional capability to image hidden fissionable materials. The tagged neutron approach is very different to other techniques based on neutron die-away or photo-fission. This work builds on the development of the Associated Particle Imaging (API) technique at the Special Technologies Laboratory (STL) [1]. Similar investigations have been performed by teams at the Oak Ridge National Laboratory (ORNL), the Khlopin Radium Institute in Russia, and by the EURITRACK collaboration in the European Union [2,3,4].

  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. Characterization of the Etna volcanic emissions through an active biomonitoring technique (moss-bags): part 1--major and trace element composition.

    Science.gov (United States)

    Calabrese, S; D'Alessandro, W; Bellomo, S; Brusca, L; Martin, R S; Saiano, F; Parello, F

    2015-01-01

    Active biomonitoring using moss-bags was applied to an active volcanic environment for the first time. Bioaccumulation originating from atmospheric deposition was evaluated by exposing mixtures of washed and air-dried mosses (Sphagnum species) at 24 sites on Mt. Etna volcano (Italy). Concentrations of major and a large suite of trace elements were analysed by inductively coupled mass and optical spectrometry (ICP-MS and ICP-OES) after total acid digestion. Of the 49 elements analysed those which closely reflect summit volcanic emissions were S, Tl, Bi, Se, Cd, As, Cu, B, Na, Fe, Al. Enrichment factors and cluster analysis allowed clear distinction between volcanogenic, geogenic and anthropogenic inputs that affect the local atmospheric deposition. This study demonstrates that active biomonitoring with moss-bags is a suitable and robust technique for implementing inexpensive monitoring in scarcely accessible and harsh volcanic environments, giving time-averaged quantitative results of the local exposure to volcanic emissions. This task is especially important in the study area because the summit area of Mt. Etna is visited by nearly one hundred thousand tourists each year who are exposed to potentially harmful volcanic emissions.

  8. Determination of contraband using fast neutron resonance technique

    Energy Technology Data Exchange (ETDEWEB)

    Bae, J.; Whang, J. [Kyunghee Univ., Dept. of Nuclear Engineering, Yongin-shi, Kyongki-do (Korea, Republic of)

    2004-07-01

    'Full-text:' Resonance technique with monoenergetic fast neutron beam is able to map features in bulk samples in a way that is sensitive to their elemental composition. It has a number of potential applications, for example, in mining and in the detection of contraband materials such as illicit drugs and explosives. By moving around the neutron detector experiences neutrons in the form of narrow line beam with different energies as the angle to the neutron source changes. Projection data was obtained using the Monte Carlo code MCNP4C. Therefore the fast neutrons scattered from an unknown object are used to determine the elemental content of the object and hence lead to its identification. Scattered features simulated for various test materials are analyzed using the HEPRO program system (PTB, Braunschweig) to determine the atom weight fractions for H. C. N, O and other elements in the materials. Atom weight fractions determined from scattering features are insensitive to neutron interactions in interfering materials surrounding the object. The simulations demonstrate that the fast neutron resonance technique (FNRT) provides reliable elemental characterization of bulk materials and has the necessary sensitivity to distinguish between drugs, explosives and other materials. (author)

  9. 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).

  10. 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).

  11. 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)

  12. 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)

  13. 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)

  14. APPLICATION OF NOVEL NEUTRON CORRELATION TECHNIQUES TO NUCLEAR MATERIAL MEASUREMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Sale, K

    2006-06-09

    Confirmation of the fissile mass of a system containing plutonium can be done using neutron multiplicity techniques. This can be accomplished with a detector system that is smaller and less costly than a standard neutron multiplicity counter (NMC). Also the fissile mass of a uranium containing system can be confirmed by passive means. Recent work at Lawrence Livermore National Laboratory has demonstrated that simple slab neutron detectors and a novel approach to data acquisition and analysis can be used to make an accurate measurement of the mass of fissile materials. Purely passive measurement of kilogram quantities of highly enriched uranium (HEU) have also been shown to be feasible. In this paper we discuss calculational tools for assessing the application of these techniques to fissile material transparency regimes. The tools required to adequately model the correlations and their application will be discussed.

  15. 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)

  16. 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...

  17. 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.

  18. 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.

  19. Analysis of neutron-reflectometry data by Monte Carlo technique

    CERN Document Server

    Singh, S

    2002-01-01

    Neutron-reflectometry data is collected in momentum space. The real-space information is extracted by fitting a model for the structure of a thin-film sample. We have attempted a Monte Carlo technique to extract the structure of the thin film. In this technique we change the structural parameters of the thin film by simulated annealing based on the Metropolis algorithm. (orig.)

  20. 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.

  1. 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

  2. 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)

  3. 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)

  4. 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)

  5. Application of neutron activation tracer sediment technique on environmental science

    Institute of Scientific and Technical Information of China (English)

    YinYi; ZhongWei-Ni; 等

    1997-01-01

    Field and laboratory inverstigations were carried out to study the transport and dispersion law of polluted sediments near wastewater outlet using neutron activation tracer technique.The direction of transport and dispersion of polluted sediments,dispersion amount in different directions,sedimentary region of polluted sediment and evaluation of polluted risk are given.This provided a new test method for the study of environmental science and added a new forecasted content for the evaluation of environmental influence.

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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

  15. Review of neutron calibration facilities and monitoring techniques: new needs for emerging fields.

    Science.gov (United States)

    Gressier, V

    2014-10-01

    Neutron calibration facilities and monitoring techniques have been developed since the middle of the 20th century to support research and nuclear power energy development. The technical areas needing reference neutron fields and related instruments were mainly cross section measurements, radiation protection, dosimetry and fission reactors, with energy ranging from a few millielectronvolts to about 20 MeV. The reference neutron fields and calibration techniques developed for these purposes will be presented in this paper. However, in recent years, emerging fields have brought new needs for calibration facilities and monitoring techniques. These new challenges for neutron metrology will be exposed with their technical difficulties.

  16. 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.

  17. 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

  18. 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.

  19. 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-...

  20. 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

  1. Neutron techniques. [for study of high-energy particles produced in large solar flares

    Science.gov (United States)

    Frye, Glenn M., Jr.; Dunphy, Philip P.; Chupp, Edward L.; Evenson, Paul

    1988-01-01

    Three experimental methods are described which hold the most promise for improved energy resolution, time resolution and sensitivity in the detection of solar neutrons on satellites and/or long duration balloon flights: the neutron calorimeter, the solar neutron track chamber, and the solar neutron decay proton detector. The characteristics of the three methods as to energy range, energy resolution, time resolution, detection efficiency, and physical properties are delineated. Earlier techniques to measure the intensity of high-energy cosmic-ray neutrons at the top of the atmosphere and to search for solar neutrons are described. The past three decades of detector development has now reached the point where it is possible to make comprehensive and detailed measurements of solar neutrons on future space missions.

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. Study of some marine bivalves as the biomonitor candidates for environmental assessment of the Jianzhou Bay by NAA and AAS

    Institute of Scientific and Technical Information of China (English)

    ZhangPei-Qun; WangWen-Qi; 等

    1998-01-01

    Some kinds of marine bivalves were selected as the biomonitor candidates to study the possibility of the environmentalassessmentof the jiaozhou Bay with biomonitors.The contents of 29 elements in bivalve samples were determined by neutron activation analysis and atomic absorption spectrometry.It is found that clam is a suitable kind of marine bivalves as a biomonitor to evaluate the environmental quality of the Jiaozhou Bay.the environmental status of some sampling sites in this marine area wastentatively assessed by the biomonitors of calm and mussel.

  8. 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 ...

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

    CERN Document Server

    Kiraly, B; Csikai, J

    2001-01-01

    Systematic measurements were carried out on the possible use of elastically backscattered Pu-Be neutrons combined with the thermal neutron reflection method for the identification of land mines and illicit drugs via he detection of H, C, N, and O elements as their major constituents. While ur present results show that these methods are capable of indicating the anomalies in bulky materials and observation of the major elements, e termination of the exact atom fractions needs further investigation.

  10. Modern Techniques for Inelastic Thermal Neutron Scattering Analysis

    Science.gov (United States)

    Hawari, A. I.

    2014-04-01

    A predictive approach based on ab initio quantum mechanics and/or classical molecular dynamics simulations has been formulated to calculate the scattering law, S(κ⇀,ω), and the thermal neutron scattering cross sections of materials. In principle, these atomistic methods make it possible to generate the inelastic thermal neutron scattering cross sections of any material and to accurately reflect the physical conditions of the medium (i.e, temperature, pressure, etc.). In addition, the generated cross sections are free from assumptions such as the incoherent approximation of scattering theory and, in the case of solids, crystalline perfection. As a result, new and improved thermal neutron scattering data libraries have been generated for a variety of materials. Among these are materials used for reactor moderators and reflectors such as reactor-grade graphite and beryllium (including the coherent inelastic scattering component), silicon carbide, cold neutron media such as solid methane, and neutron beam filters such as sapphire and bismuth. Consequently, it is anticipated that the above approach will play a major role in providing the nuclear science and engineering community with its needs of thermal neutron scattering data especially when considering new materials where experimental information may be scarce or nonexistent.

  11. 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.

  12. 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)

  13. A high-resolution neutron spectra unfolding method using the Genetic Algorithm technique

    CERN Document Server

    Mukherjee, B

    2002-01-01

    The Bonner sphere spectrometers (BSS) are commonly used to determine the neutron spectra within various nuclear facilities. Sophisticated mathematical tools are used to unfold the neutron energy distribution from the output data of the BSS. This paper highlights a novel high-resolution neutron spectra-unfolding method using the Genetic Algorithm (GA) technique. The GA imitates the biological evolution process prevailing in the nature to solve complex optimisation problems. The GA method was utilised to evaluate the neutron energy distribution, average energy, fluence and equivalent dose rates at important work places of a DIDO class research reactor and a high-energy superconducting heavy ion cyclotron. The spectrometer was calibrated with a sup 2 sup 4 sup 1 Am/Be (alpha,n) neutron standard source. The results of the GA method agreed satisfactorily with the results obtained by using the well-known BUNKI neutron spectra unfolding code.

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

    Energy Technology Data Exchange (ETDEWEB)

    Poenitz, W.P.

    1981-07-01

    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 (/sup 238/U and /sup 232/Th) 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.

  15. 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.

  16. 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)

  17. 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.

  18. 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.

  19. 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)

  20. Development of a neutron guide tube production technique at KAERI

    Science.gov (United States)

    Cho, Sang-Jin; Seung, Baek-Soek; Lee, Chang-Hee; Kim, Hark-Rho

    2006-11-01

    In this paper, we present KAERI's technical development status for a neutron guide tube fabrication. To achieve a high uniformity, very low roughness and perfect interface during the layer growth process, a sputtering machine was developed whereby various deposition parameters can be controlled. The Ni mirrors fabricated with this coating equipment show a neutron reflectivity of 97% at the critical angle and the Ni/Ti-supermirrors show ( M=2) 84%. For a substrate alignment and assembly for the guide elements, a non-contact measurement apparatus equipped with optical microscopes was developed instead of using a 3-axis measuring machine. By employing this optical equipment, it was possible to assemble a neutron guide with an accuracy in the lateral direction of 0.005 mm and in the vertical direction of 0.01 mm.

  1. 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)

  2. 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)

  3. Dynamic neutron scattering on incoherent systems using efficient resonance spin flip techniques

    Energy Technology Data Exchange (ETDEWEB)

    Häussler, Wolfgang [Heinz Maier-Leibnitz Zentrum, Technische Universität München, D-85748 Garching, Germany and Physik-Department E21, Technische Universität München, D-85748 Garching (Germany); Kredler, Lukas [Physik-Department E21, Technische Universität München, D-85748 Garching (Germany)

    2014-05-15

    We have performed numerical ray-tracing Monte-Carlo-simulations of incoherent dynamic neutron scattering experiments. We intend to optimize the efficiency of incoherent measurements depending on the fraction of neutrons scattered without and with spin flip at the sample. In addition to conventional spin echo, we have numerically and experimentally studied oscillating intensity techniques. The results point out the advantages of these different spin echo variants and are an important prerequisite for neutron resonance spin echo instruments like RESEDA (FRM II, Munich), to choose the most efficient technique depending on the scattering vector range and the properties of the sample system under study.

  4. A single-shot nanosecond neutron pulsed technique for the detection of fissile materials

    Science.gov (United States)

    Gribkov, V.; Miklaszewski, R. A.; Chernyshova, M.; Scholz, M.; Prokopovicz, R.; Tomaszewski, K.; Drozdowicz, K.; Wiacek, U.; Gabanska, B.; Dworak, D.; Pytel, K.; Zawadka, A.

    2012-07-01

    A novel technique with the potential of detecting hidden fissile materials is presented utilizing the interaction of a single powerful and nanosecond wide neutron pulse with matter. The experimental system is based on a Dense Plasma Focus (DPF) device as a neutron source generating pulses of almost mono-energetic 2.45 MeV and/or 14.0 MeV neutrons, a few nanoseconds in width. Fissile materials, consisting of heavy nuclei, are detected utilizing two signatures: firstly by measuring those secondary fission neutrons which are faster than the elastically scattered 2.45 MeV neutrons of the D-D reaction in the DPF; secondly by measuring the pulses of the slower secondary fission neutrons following the pulse of the fast 14 MeV neutrons from the D-T reaction. In both cases it is important to compare the measured spectrum of the fission neutrons induced by the 2.45 MeV or 14 MeV neutron pulse of the DPF with theoretical spectra obtained by mathematical simulation. Therefore, results of numerical modelling of the proposed system, using the MCNP5 and the FLUKA codes are presented and compared with experimental data.

  5. 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)

  6. 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)

  7. 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.

  8. 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...... reference materials as well as fertilizer materials are compared by literature value and spectrophotometric measurements, respectively. In both cases good agreement is obtained....

  9. 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...

  10. 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)

  11. Characterization of the silicon+6LiF thermal neutron detection technique

    Science.gov (United States)

    Pappalardo, A.; Barbagallo, M.; Cosentino, L.; Marchetta, C.; Musumarra, A.; Scirè, C.; Scirè, S.; Vecchio, G.; Finocchiaro, P.

    2016-02-01

    The worldwide need to replace 3He for neutron detection has triggered research and development on new technologies and methods. A promising one is based on commercial solid state silicon detectors coupled with thin neutron converter layers containing 6Li. After proving the feasibility of this technique, we characterized the behavior of such a detector with different converter layer thicknesses. In this paper we also disentangle other contributions to the overall spectrum shape observed with this kind of detector, proving that its detection efficiency can be made reasonably high and that the gamma/neutron discrimination capability is comparable to that of 3He tubes.

  12. Characterization of the silicon+6LiF thermal neutron detection technique

    CERN Document Server

    Pappalardo, A; Cosentino, L; Marchetta, C; Musumarra, A; Scirè, C; Scirè, S; Vecchio, G; Finocchiaro, P

    2015-01-01

    The worldwide need to replace 3He for the neutron detection has triggered R&D on new technologies and methods. A promising one is based on commercial solid state silicon detectors coupled with thin neutron converter layers containing 6Li. After proving the feasibility of this technique, we characterized the behavior of such a detector with different converter layer thicknesses. In this paper we also disentangle other contributions to the overall spectrum shape observed with this kind of detector, proving that its detection efficiency can be made reasonably high and that the gamma/neutron discrimination capability is comparable to the one of 3He tubes.

  13. 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...

  14. 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...

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

    NARCIS (Netherlands)

    Bom, V.; Osman, A.M; 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

  16. 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

  17. 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

  18. 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

  19. 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%.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, F.J.O. [Instituto de Engenharia Nuclear, Cidade Universitaria, Rio de Janeiro, CEP 21945-970, Caixa Postal 68550 (Brazil)], E-mail: fferreira@ien.gov.br; Crispim, V.R.; Silva, A.X. [DNC/Poli, PEN COPPE CT, UFRJ Universidade Federal do Rio de Janeiro, CEP 21941-972, Caixa Postal 68509, Rio de Janeiro (Brazil)

    2010-06-15

    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.

  1. 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...

  2. 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.

  3. 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.

  4. 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...

  5. 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

  6. 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)

  7. 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

  8. 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)

  9. 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

  10. 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)

  11. 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.)

  12. 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.

  13. 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.

  14. Neutron scattering at high temperature and levitation techniques

    Science.gov (United States)

    Cuello, G. J.; Cristiglio, V.; Hennet, L.; Puente-Orench, I.

    2014-11-01

    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.

  15. 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

  16. 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)

  17. 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)

  18. 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)

  19. 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

  20. 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.

  1. 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

  2. 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.

  3. 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)

  4. Ethics in biomonitoring for occupational health.

    Science.gov (United States)

    Manno, M; Sito, F; Licciardi, L

    2014-12-01

    Biological monitoring, i.e., the use of biomarkers for the measurement of systemic human exposure, effects and susceptibility to chemicals has increased considerably in recent years. Biomonitoring techniques, originally limited to a few metals and other chemicals in the workplace, are currently applied to a large number of exposure situations and have become a useful tool for occupational and environmental health risk assessment. Almost any biomonitoring program, however, entails a number of relevant ethical issues, which concern all the phases of the entire process, from the selection of the biomarker to the study design, from the collection, storage and analysis of the biological sample to the interpretation, communication and management of the results, from the (truly?) informed consent of the worker to the independence and autonomy of the occupational health professional. These issues require a balanced assessment of the interests and responsibilities of all the parties, the worker primarily, but also the employer, the occupational health professional, the health authorities and, for research studies on new biomarkers, also the scientists involved. Ideally, decisions of ethical relevance concerning biomarkers should be based on, and respectful of the best scientific, legal and ethical evidence available. When, however, a conflict should arise, before any decision is taken a thorough risk-benefit analysis should be done, at the beginning of the process and after listening to the workers and the management involved, by the occupational physician or scientist, based on his/her professional experience, independent judgement and individual responsibility. PMID:25447455

  5. Neutrons, X rays, and gamma rays: Imaging detectors, material characterization techniques, and applications; Proceedings of the Meeting, San Diego, CA, July 21, 22, 1992

    Science.gov (United States)

    Carpenter, John M.; Cline, David B.; Lanza, Richard; Mildner, David F. R.

    1993-02-01

    Topics addressed include scintillating fiber technology and applications; materials characterization techniques using gamma-rays, X-rays, and neutrons; survey of principles; systems in operation; new detection systems; and applications and sources of neutrons. Also discussed are a directional fast neutron detector using scintillating fibers and electrooptics; a dark-matter detector, a novel light counter, and the ICARUS project; the major problems of MeV and GeV gamma-ray astrophysics; a compact, tunable source of monochromatic highly-directional X-rays; recent advances in neutron tomography; tailoring neutron spectra for fast neutron spectroscopy; area detectors for neutron protein crystallography; features of microstrip proportional counters; thermal neutron imaging using microchannel plates; an image plate neutron detector; a characterization of an accelerator neutron source based on the Be(d,n) reaction; and tailoring neutron spectra for fast neutron spectroscopy. (No individual items are abstracted in this volume)

  6. 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

  7. 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)

  8. 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)

  9. 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...

  10. 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...

  11. 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.

  12. Neutron irradiation of Czochralski and temperature gradient technique grown YAG crystals

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Chengyong [Faculty of Scinece, Ningbo University, Ningbo 315211 (China)]. E-mail: Jiangchengyong@nbu.edu.cn

    2006-03-01

    Absorption, fluorescence and thermoluminescence spectra are presented for 1.5-MeV neutron-irradiated YAG crystals grown by Czochralski (CZ) and temperature gradient technique (TGT). F{sup +} centers were formed in both YAG samples and valence of iron impurities in TGT-grown YAG crystals switched from divalent to trivalent after neutron irradiation. At 350 and 300 deg. C thermoluminescence was observed in CZ-grown and TGT-grown YAG crystals, respectively, and assigned to irradiation-induced color centers. Calculated with the initial elevation method, thermoluminescence trap depths of the 350 deg. C band and of the 300 deg. C band are 0.379 and 0.768 eV, respectively. The significant difference in thermoluminescence intensities between CZ- and TGT-grown YAG crystals is associated with the irradiation-induced color centers and quenching effect of Fe{sup 3+} ions.

  13. 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.

  14. 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...

  15. 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.

  16. Further Evaluation of the Neutron Resonance Transmission Analysis (NRTA) Technique for Assaying Plutonium in Spent Fuel

    Energy Technology Data Exchange (ETDEWEB)

    J. W. Sterbentz; D. L. Chichester

    2011-09-01

    This is an end-of-year report (Fiscal Year (FY) 2011) for the second year of effort on 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 second-year goals for this project included: (1) assessing the neutron source strength needed for the NRTA technique, (2) estimating count times, (3) assessing the effect of temperature on the transmitted signal, (4) estimating plutonium content in a spent fuel assembly, (5) providing a preliminary assessment of the neutron detectors, and (6) documenting 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 work performed over a nine month period from January-September 2011 and is to be considered a follow-on or add-on report to our previous published summary report from December 2010 (INL/EXT-10-20620).

  17. 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.

  18. 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)

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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)

  5. 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)

  6. 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

  7. 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.

  8. 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)

  9. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-01-19

    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 previously achieved. Numerical simulations indicate that the spatial resolution of this technique will be about 15 $\\mu$m, and the intrinsic detection efficiency for thermal neutrons will be about 3 %. We compare the proposed technique with other neutron detection techniques and analyze its advantages and disadvantages.

  11. 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 ...

  12. 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.

  13. 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)

  14. 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)

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. 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)

  1. 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...

  2. Application of the coincidence counting technique to DD neutron spectrometry data at the NIF, OMEGA, and Z

    Science.gov (United States)

    Lahmann, B.; Milanese, L. M.; Han, W.; Gatu Johnson, M.; Séguin, F. H.; Frenje, J. A.; Petrasso, R. D.; Hahn, K. D.; Jones, B.

    2016-11-01

    A compact neutron spectrometer, based on a CH foil for the production of recoil protons and CR-39 detection, is being developed for the measurements of the DD-neutron spectrum at the NIF, OMEGA, and Z facilities. As a CR-39 detector will be used in the spectrometer, the principal sources of background are neutron-induced tracks and intrinsic tracks (defects in the CR-39). To reject the background to the required level for measurements of the down-scattered and primary DD-neutron components in the spectrum, the Coincidence Counting Technique (CCT) must be applied to the data. Using a piece of CR-39 exposed to 2.5-MeV protons at the MIT HEDP accelerator facility and DD-neutrons at Z, a significant improvement of a DD-neutron signal-to-background level has been demonstrated for the first time using the CCT. These results are in excellent agreement with previous work applied to DT neutrons.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kehler, P.

    1982-03-01

    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.

  4. 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.

  5. 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.

  6. 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.

  7. Acceptance scan technique for the drift tube linac of the spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, D. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)]. E-mail: jeond@ornl.gov; Stovall, J. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Takeda, H. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Nath, S. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Billen, J. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Young, L. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Kisselev, I. [Institute for Nuclear Research of RAS, Troitsk, Russia (Russian Federation); Shishlo, A. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Aleksandrov, A. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Assadi, S. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Chu, C.M. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Cousineau, S. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Danilov, V. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Galambos, J. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Henderson, S. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Kim, S. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Kravchuk, L. [Institute for Nuclear Research of RAS, Troitsk, Russia (Russian Federation); Tanke, E. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2007-01-01

    For high intensity proton accelerators, it is vital to reduce the machine activation by minimizing the beam loss from many sources. One of such sources is longitudinal mismatch. To minimize a potential mismatch, it is important to set accurately the rf set-point (rf field amplitude and phase) of a high-intensity linac such as the drift tube linac (DTL) of the spallation neutron source. A widely used technique called the acceptance scan was studied extensively and applied successfully to tune the DTL tanks since the initial commissioning. From the acceptance scan one can obtain the longitudinal beam profile at the entrance of each DTL tank. But except tank 1, acceptance scan alone cannot determine the incoming beam energy deviation, leading to small uncertainties in the rf set point.

  8. GENERALISATION OF RADIATOR DESIGN TECHNIQUES FOR PERSONAL NEUTRON DOSEMETERS BY UNFOLDING METHOD.

    Science.gov (United States)

    Oda, K; Nakayama, T; Umetani, K; Kajihara, M; Yamauchi, T

    2016-09-01

    A novel technique for designing a radiator suitable for personal neutron dosemeter based on plastic track detector was discussed. A multi-layer structure has been proposed in the previous report, where the thicknesses of plural polyethylene (PE) layers and insensitive ones were determined by iterative calculations of double integral. In order to arrange this procedure and make it more systematic, unfolding calculation has been employed to estimate an ideal radiator containing an arbitrary hydrogen concentration. In the second step, realistic materials replaced it with consideration of minimisation of the layer number and commercial availability. A radiator consisting of three layers of PE, Upilex and Kapton sheets was finally designed, for which a deviation in the energy dependence between 0.1 and 20 MeV could be controlled within 18 %. An applicability of fluorescent nuclear track detector element has also been discussed. PMID:26378225

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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)

  14. 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

  15. 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

  16. 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)

  17. 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

  18. 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)

  19. 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.)

  20. STRATEGIC BIOMONITORING INITIATIVES: MOVING THE SCIENCE FORWARD

    Science.gov (United States)

    Biomonitoring programs in the United States and Europe demonstrate the vast array of data that are publicly available for the evaluation of exposure trends, identification of susceptible populations, detection of emerging chemical risks, the conduct of epidemiology studies, and ...

  1. 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

  2. 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)

  3. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

    Daud, M.; Khalid, N.; Waheed, S.; Wasim, M.; Arif, M.; Zaidi, J.H. [Pakistan Institute of Nuclear Science and Technology, Islamabad (Pakistan). Chemistry Div.

    2011-07-01

    The present paper 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 (INAA) and Atomic Absorption Spectrometric (AAS) techniques. The leaf samples were collected in spring, summer and winter seasons from various sites in Islamabad with different types of anthropogenic activities as well as from a reference site with minimum of such activities. Twenty four soil samples from the respective sites were also analyzed. The reliability of the adopted procedures was established by analyzing the certified reference materials, i.e., citrus leaves-1572 and soil-7, from NIST and IAEA, respectively, under identical experimental conditions and comparing the results obtained with the certified values which are in quite good agreement with each other. The enrichment values and Pollution Load Index (PLI) of the determined elements were computed and discussed accordingly. The elemental translocation from soil to roots, stem and leaves has also been studied by analyzing these parts of the same plant. The results indicated that the leaves of Morus nigra plant have promising potential to monitor the extent of air pollution in the vicinity of industrial as well as in high traffic areas. (orig.)

  5. 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

  6. 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

  7. Pulsed and monoenergetic beams for neutron cross-section measurements using activation and scattering techniques at Triangle Universities Nuclear Laboratory

    Science.gov (United States)

    Hutcheson, A.; Angell, C. T.; Becker, J. A.; Boswell, M.; Crowell, A. S.; Dashdorj, D.; Fallin, B.; Fotiades, N.; Howell, C. R.; Karwowski, H. J.; Kelley, J. H.; Kiser, M.; Macri, R. A.; Nelson, R. O.; Pedroni, R. S.; Tonchev, A. P.; Tornow, W.; Vieira, D. J.; Weisel, G. J.; Wilhelmy, J. B.

    2007-08-01

    In support of the Stewardship Science Academic Alliances initiative, an experimental program has been developed at Triangle Universities Nuclear Laboratory (TUNL) to measure (n,xn) cross-sections with both in-beam and activation techniques with the goal of improving the partial cross-section database for the NNSA Stockpile Stewardship Program. First experimental efforts include excitation function measurements on 235,238U and 241Am using pulsed and monoenergetic neutron beams with En = 5-15 MeV. Neutron-induced partial cross-sections were measured by detecting prompt γ rays from the residual nuclei using various combinations of clover and planar HPGe detectors in the TUNL shielded neutron source area. Complimentary activation measurements using DC neutron beams have also been performed in open geometry in our second target area. The neutron-induced activities were measured in the TUNL low-background counting area. In this presentation, we include detailed information about the irradiation procedures and facilities and preliminary data on first measurements using this capability.

  8. Pulsed and monoenergetic beams for neutron cross-section measurements using activation and scattering techniques at Triangle Universities Nuclear Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Hutcheson, A. [Triangle Universities Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 (United States)]. E-mail: hutch@tunl.duke.edu; Angell, C.T. [Triangle Universities Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 (United States); Becker, J.A. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States); Boswell, M. [Triangle Universities Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 (United States); Crowell, A.S. [Triangle Universities Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 (United States); Dashdorj, D. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States); Fallin, B. [Triangle Universities Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 (United States); Fotiades, N. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Howell, C.R.; Karwowski, H.J.; Kelley, J.H.; Kiser, M. [Triangle Universities Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 (United States); Macri, R.A. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States); Nelson, R.O. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Pedroni, R.S. [NC A and T State University, 1601 East Market Street, Greensboro, NC 27411 (United States); Tonchev, A.P.; Tornow, W. [Triangle Universities Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 (United States); Vieira, D.J. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Weisel, G.J. [Penn State Altoona, 3000 Ivyside Park, Altoona, PA 16601 (United States); Wilhelmy, J.B. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States)

    2007-08-15

    In support of the Stewardship Science Academic Alliances initiative, an experimental program has been developed at Triangle Universities Nuclear Laboratory (TUNL) to measure (n,xn) cross-sections with both in-beam and activation techniques with the goal of improving the partial cross-section database for the NNSA Stockpile Stewardship Program. First experimental efforts include excitation function measurements on {sup 235,238}U and {sup 241}Am using pulsed and monoenergetic neutron beams with E {sub n} = 5-15 MeV. Neutron-induced partial cross-sections were measured by detecting prompt {gamma} rays from the residual nuclei using various combinations of clover and planar HPGe detectors in the TUNL shielded neutron source area. Complimentary activation measurements using DC neutron beams have also been performed in open geometry in our second target area. The neutron-induced activities were measured in the TUNL low-background counting area. In this presentation, we include detailed information about the irradiation procedures and facilities and preliminary data on first measurements using this capability.

  9. 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...

  10. 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)

  11. 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)

  12. 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.)

  13. 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

  14. 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.)

  15. 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.

  16. 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.

  17. 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

  18. 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

  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. 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.)

  2. 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.

  3. 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

  4. 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.

  5. The LUPIN detector supporting least intrusive beam monitoring technique through neutron detection

    CERN Document Server

    Manessi, G P; Welsch, C; Caresana, M; Ferrarini, M

    2013-01-01

    The Long interval, Ultra-wide dynamic Pile-up free Neutron rem counter (LUPIN) is a novel detector initially developed for radiation protection purposes, specifically conceived for applications in pulsed neutron fields. The detector has a measurement capability varying over many orders of neutron burst intensity, from a single neutron up to thousands of interactions for each burst, without showing any saturation effect. Whilst LUPIN has been developed for applications in the radiation protection fields, its unique properties make it also well suited to support other beam instrumentation. In this contribution, the design of LUPIN is presented in detail and results from measurements carried out in different facilities summarize its main characteristics. Its potential use as beam loss monitor (BLM) and complementary detector for non-invasive beam monitoring purposes (e.g. to complement a monitor based on proton beam “halo” detection) in medical accelerators is then examined. In the context of its application...

  6. 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...

  7. 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...

  8. 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.

  9. 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

  10. 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

  11. 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...

  12. 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

  13. 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.

  14. Actinide neutron induced cross section measurements using the oscillation technique in the Minerve reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, B.; Leconte, P.; Gruel, A.; Antony, M.; Di-Salvo, J.; Hudelot, J.P.; Pepino, A.; Lecluze, A. [CEA Cadarache, DEN/CAD/DER/SPRC/LEPh, 13 - Saint-Paul-lez-Durance (France)

    2009-07-01

    CEA is deeply involved research programs concerning nuclear fuel advanced studies (actinides, plutonium), waste management, the scientific and technical support of French PWR reactors and EPR reactor, and innovative systems. In this framework, specific neutron integral experiments have been carried out in the critical ZPR (zero power reactor) facilities of the CEA at Cadarache such as MINERVE, EOLE and MASURCA. This paper deals with MINERVE Pool Reactor experiments. MINERVE is mainly devoted to neutronics studies of different reactor core types. The aim is to improve the knowledge of the integral absorption cross sections of actinides (OSMOSE program), of new absorbers (OCEAN program) and also for fission Products (CBU program) in thermal, epithermal and fast neutron spectra. (authors)

  15. 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

  16. 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...

  17. 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)

  18. 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)

  19. 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)

  20. 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

  1. Implementation of variance-reduction techniques for Monte Carlo nuclear logging calculations with neutron sources

    NARCIS (Netherlands)

    Maucec, M

    2005-01-01

    Monte Carlo simulations for nuclear logging applications are considered to be highly demanding transport problems. In this paper, the implementation of weight-window variance reduction schemes in a 'manual' fashion to improve the efficiency of calculations for a neutron logging tool is presented. Th

  2. 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)

  3. 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)

  4. 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

  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. 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

  7. 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)

  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. 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.

  11. 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)

  12. 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)

  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. 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

  16. 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.

  17. 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)

  18. 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.

  19. 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.

  20. 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)

  1. 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.

  2. 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)

  3. 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...

  4. Choppers to optimise the repetition rate multiplication technique on a direct geometry neutron chopper spectrometer

    DEFF Research Database (Denmark)

    Vickery, Anette; Deen, P. P.

    2014-01-01

    In recent years the use of repetition rate multiplication (RRM) on direct geometry neutron spectrometers has been established and is the common mode of operation on a growing number of instruments. However, the chopper configurations are not ideally optimised for RRM with a resultant 100 fold flu...... in time resolution probed for a single European Spallation Source (ESS) period, which is ideal to probe complex relaxational behaviour. These two chopper configurations have been simulated for the Versatile Optimal Resolution direct geometry spectrometer, VOR, that will be built at ESS....

  5. 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

  6. 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)

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

    NARCIS (Netherlands)

    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 s

  8. Neutron Resonance Transmission Analysis (NRTA): A Nondestructive Assay Technique for the Next Generation Safeguards Initiative’s Plutonium Assay Challenge

    Energy Technology Data Exchange (ETDEWEB)

    J. W. Sterbentz; D. L. Chichester

    2010-12-01

    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.

  9. 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.

  10. 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

  11. 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)

  12. Description of a nuclear interaction in the Keldysh diagram technique and the problem of neutrino luminosity of neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Voskresenskii-breve, D.N.; Senatorov, A.V.

    1987-03-01

    The Keldysh diagram technique has been formulated for description of equilibrium and nonequilibrium nuclear systems. A nuclear interaction is constructed on the basis of the theory of finite Fermi systems. The formalism is applied to calculation of the probabilities of various processes. The possibilities of the proposed approach are demonstrated in calculation of the luminosity of the principal reactions which contribute to the cooling of neutron stars. The luminosity is calculated for the process nn..-->..npenu-bar, which incurs in a dense nucleon medium very differently than in a rarefied medium. The dependence of the luminosity of the nucleon--nucleon correlation factor is analyzed. The formalism is applied to systems with pairing. The contribution to the luminosity of the reactions n/sub pa/..-->..n..nu..nu-bar and p/sub pa/..-->..p..nu..nu-bar, which are possible only in the presence of nucleon pairing, is calculated. The consequences of the results in the scenario of neutron-star cooling are discussed.

  13. 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.

  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. 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.

  17. 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.

  18. 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.

  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. 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.

  1. 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

  2. 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

  3. Direct Mass Measurements in the Light Neutron-Rich Region Using a Combined Energy and Time-of-Flight Technique

    Science.gov (United States)

    Pillai, C.; Swenson, L. W.; Vieira, D. J.; Butler, G. W.; Wouters, J. M.; Rokni, S. H.; Vaziri, K.; Remsberg, L. P.

    This experiment has demonstrated that direct mass measurements can be performed (albeit of low precision in this first attempt) using the M proportional to ET(2) 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 (BETA)-stability. Mass measurements for several neutron-rich light nuclei ranging from C-17 to NE-26 have been performed. In all cases these measurements agree with the latest mass compilation of Wapstra and Audi. The masses of N-20 N and F-24 have been determined for the first time.

  4. 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)

  5. 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

  6. 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

  7. 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)

  8. 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)

  9. The First Nations Biomonitoring Initiative-FNBI.

    Science.gov (United States)

    La Corte, Elsa; Wuttke, Stuart

    2012-02-01

    The First Nations Biomonitoring Initiative (FNBI) pilot study was implemented in the winter 2010/2011, sampling 252 First Nations people on reserve in Canada for a suite of chemical contaminants following Cycle 1 of the Canadian Health Measures Survey (CHMS). Results will be sent confidentially to participants and a community report will be presented after the analysis of results, expected to be completed by fall of 2011. The national scale of the study will take place during the summer 2011/2012 and aims to sample thirteen communities with a participation of 42 First Nations people per community. Results are expected for spring 2012/2013.

  10. An application of CCD read-out technique to neutron distribution measurement using the self-activation method with a CsI scintillator plate

    Science.gov (United States)

    Nohtomi, Akihiro; Kurihara, Ryosuke; Kinoshita, Hiroyuki; Honda, Soichiro; Tokunaga, Masaaki; Uno, Heita; Shinsho, Kiyomitsu; Wakabayashi, Genichiro; Koba, Yusuke; Fukunaga, Junichi; Umezu, Yoshiyuki; Nakamura, Yasuhiko; Ohga, Saiji

    2016-10-01

    In our previous paper, the self-activation of an NaI scintillator had been successfully utilized for detecting photo-neutrons around a high-energy X-ray radiotherapy machine; individual optical pulses from the self-activated scintillator are read-out by photo sensors such as a photomultiplier tube (PMT). In the present work, preliminary observations have been performed in order to apply a direct CCD read-out technique to the self-activation method with a CsI scintillator plate using a Pu-Be source and a 10-MV linac. In conclusion, it has been revealed that the CCD read-out technique is applicable to neutron measurement around a high-energy X-ray radiotherapy machine with the self-activation of a CsI plate. Such application may provide a possibility of novel method for simple neutron dose-distribution measurement.

  11. 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.)

  12. 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 $\

  13. 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)

  14. 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

  15. 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)

  16. 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.

  17. Imaging with Scattered Neutrons

    CERN Document Server

    Ballhausen, H; Gähler, R; Trapp, M; Van Overberghe, A

    2006-01-01

    We describe a novel experimental technique for neutron imaging with scattered neutrons. These scattered neutrons are of interest for condensed matter physics, because they permit to reveal the local distribution of incoherent and coherent scattering within a sample. In contrast to standard attenuation based imaging, scattered neutron imaging distinguishes between the scattering cross section and the total attenuation cross section including absorption. First successful low-noise millimeter-resolution images by scattered neutron radiography and tomography are presented.

  18. 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)

  19. $\\beta$-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.

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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)

  5. 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

  6. 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.

  7. Spontaneous-fission decay constant of sup 2 sup 3 sup 8 U measured by nuclear track techniques without neutron irradiation

    CERN Document Server

    Guedes, S; Iunes, P J; Tello, S C A; Sarkis, J E S; Kakazu, M H; Saiki, M; Oliveira, K M G; Paulo, S R

    2003-01-01

    A value of the decay constant for spontaneous fission of sup 2 sup 3 sup 8 U, lambda sub f , determined by particle-track detector techniques, is presented. The main source of systematic error in fission-track measurements of lambda sub f , the so called 'neutron dosimetry', has been avoided. Instead of calibrating the neutron source and the usual mica detector through tracks of sup 2 sup 3 sup 5 U fission induced by thermal neutrons, spontaneous-fission tracks and alpha-particle tracks of sup 2 sup 3 sup 8 U and sup 2 sup 4 sup 2 Pu were used. A value of lambda sub f = (8.66+-0.38) x 10 sup - sup 1 sup 7 y sup - sup 1 has been obtained.

  8. A comparison in the reconstruction of neutron spectrums using classical iterative techniques; Una comparacion en la reconstruccion de espectros de neutrones utilizando tecnicas iterativas clasicas

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz R, J. M. [Departamento de Electrotecnia y Electronica, Escuela Politecnica Superior, Av. Menendez Pidal s/n, 14004 Cordoba (Spain); Martinez B, M. R.; Vega C, H. R. [Unidad Academica de Estudios Nucleares, Universidad Autonoma de Zacatecas, Cipres 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Gallego, E. [Departamento de Ingenieria Nuclear, Universidad Politecnica de Madrid, Jose Gutierrez Abascal 2, 28006 Madrid (Spain)], e-mail: morvymm@yahoo.com.mx

    2009-10-15

    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)

  9. 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...

  10. Biomonitoring human exposure to environmental carcinogenic chemicals

    DEFF Research Database (Denmark)

    Farmer, P.B.; Sepai, O.; Lawrence, R.;

    1996-01-01

    A coordinated study was carried out on the development, evaluation and application of biomonitoring procedures for populations exposed to environmental genotoxic pollutants. The procedures used involved both direct measurement of DNA or protein damage (adducts) and assessment of second biological...... effects (mutation and cytogenetic damage). Adduct detection at the level of DNA or protein (haemoglobin) was carried out by 32P-postlabelling, immunochemical, HPLC or mass spectrometric methods. Urinary excretion products resulting from DNA damage were also estimated (immunochemical assay, mass...... aberrations and sister chromatid exchanges) and mutation frequency was estimated at a number of loci including the hprt gene and genes involving in cancer development. Blood and urine samples from individuals exposed to urban pollution were collected. Populations exposed through occupational or medical...

  11. Study on an innovative fast reactor utilizing hydride neutron absorber development of coating technique on cladding inner surface

    International Nuclear Information System (INIS)

    The study to extend the control rod life of the Fast Reactor (FR) and to compress its excess reactivity are being performed by adopting the hafnium hydride (HfHx) for control rod material and by using the gadolinium hydride (GdHx) burnable poison (BP) for the reactivity recession, respectively. In the program named 'Study on an innovative Fast Reactor utilizing Hydride Neutron Absorber', the coating technique on inner surface of cladding has been developed to prevent hydrogen transfer through cladding at occasions of the temperature rise events. The Cr2O3 coating (chromizing) and the Al2O3 coating (calorizing) were selected for the coating techniques from the viewpoint of stability under in-core conditions. Following tests were performed for austenitic steel SUS316 which is widely used in FRs and for ferritic steel SUS430. The SUS430 was selected to simulate the ODS (Oxide Dispersion Strengthened ferritic steel) which is the attractive candidate material for the high burn-up FR. Examination of coating processing conditions by using short length claddings (100-200 mm). Approval of coating conditions to mock-up length cladding (1000 mm). Measurement of hydrogen transfer coefficient. Then appropriate conditions for coating were clarified and the formation of homogeneous films of both chromizing and calorizing was achieved on the inner surfaces of long length claddings (1000 mm). The hydrogen transfer experiments showed that the hydrogen transfer coefficient of coated SUS316 and SUS430 can be reduced to below 1/10 of SUS316 raw material. (author)

  12. Methodological aspects and development of techniques for neutron activation analysis of microcomponents in materials of geologic origin

    International Nuclear Information System (INIS)

    Some aspects of the activation analysis methodology applied to geological samples activated in nuclear reactors were studied, and techniques were developed for the determination of various elements in different types of matrixes, using gamma spectrometry for the measurement of the products. The consideration of the methodological aspects includes the study of the working conditions, the preparation of samples and standards, irradiations, treatment of the irradiated material, radiochemical separation and measurement. Experiments were carried out on reproducibility and errors in relation to the behaviour of the measurement equipment and that of the methods of area calculation (total area, Covell and Wasson), as well as on the effects of geometry variations on the results of the measurements, the RA-3 reactors's flux variations, and the homogeneity of the samples and standards. Also studied were: the selection of the conditions of determination, including the irradiation and decay times; the irradiation with thermal and epithermal neutrons; the measurement with the use of absorbers, and the resolution of complex peaks. Both non-destructive and radiochemical separation techniques were developed for the analysis of 5 types of geological materials. These methods were applied to the following determinations: a) In, Cd, Mn, Ga and Co in blende; b) La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu in fluorites; c) La, Ca, Eu, Tb, Yb, Se and Th in barites and celestites; d) Cu and Zn in soils. The spectral interferences or those due to nuclear reactions were studied and evaluated by mathematical calculation. (M.E.L.)

  13. 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)

  14. Comparative study between the PIXE technique and neutron activation analysis for Zinc determination; Estudo comparativo entre a tecnica de inducao de raios X por particulas e analise por ativacao com neutrons na determinacao do metal pesado zinco

    Energy Technology Data Exchange (ETDEWEB)

    Cruvinel, Paulo Estevao; Crestana, Silvio [Empresa Brasileira de Pesquisa Agropecuaria, Sao Carlos, SP (Brazil). CNPDIA. E-mail: cruvinel@cnpdia.embrapa.br; Armelin, Maria Jose Aguirre [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Artaxo Netto, Paulo Eduardo [Sao Paulo Univ., SP (Brazil). Inst. de Fisica

    1997-07-01

    This work presents a comparative study between the PIXE, proton beams and neutron activation analysis (NAA) techniques, for determination of total zinc concentration. Particularly, soil samples from the Pindorama, Instituto Agronomico de Campinas, Sao Paulo State, Brazil, experimental station have been analysed and measuring the zinc contents in {mu}g/g. The results presented good correlation between the mentioned techniques. The PIXE and NAA analyses have been carried out by using the series S, 2.4 MeV proton beams Pelletron accelerator and the IPEN/CNEN-IEA-R1 reactor, both installed at the Sao Paulo - Brazil university.

  15. 235U Determination using In-Beam Delayed Neutron Counting Technique at the NRU Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, M. T. [Los Alamos National Laboratory; Bentoumi, G. [Canadian Nuclear Laboratories; Corcoran, E. C. [Royal Military College of Canada; Dimayuga, I. [Canadian Nuclear Laboratories; Kelly, D. G. [Royal Military College of Canada; Li, L. [Canadian Nuclear Laboratories; Sur, B. [Canadian Nuclear Laboratories; Rogge, R. B. [Canadian Nuclear Laboratories

    2015-11-17

    This paper describes a collaborative effort that saw the Royal Military College of Canada (RMC)’s delayed neutron and gamma counting apparatus transported to Canadian Nuclear Laboratories (CNL) for use in the neutron beamline at the National Research Universal (NRU) reactor. Samples containing mg quantities of fissile material were re-interrogated, and their delayed neutron emissions measured. This collaboration offers significant advantages to previous delayed neutron research at both CNL and RMC. This paper details the determination of 235U content in enriched uranium via the assay of in-beam delayed neutron magnitudes and temporal behavior. 235U mass was determined with an average absolute error of ± 2.7 %. This error is lower than that obtained at RMCC for the assay of 235U content in aqueous solutions (3.6 %) using delayed neutron counting. Delayed neutron counting has been demonstrated to be a rapid, accurate, and precise method for special nuclear material detection and identification.

  16. Measurement of Insulation Compaction in the Cryogenic Fuel Tanks at Kennedy Space Center by Fast/Thermal Neutron Techniques

    Science.gov (United States)

    Livingston, R. A.; Schweitzer, J. S.; Parsons, Ann M.; Arens, Ellen E.

    2010-01-01

    The liquid hydrogen and oxygen cryogenic storage tanks at John F. Kennedy Space Center (KSC) use expanded perlite as thermal insulation. Th ere is evidence that some of the perlite has compacted over time, com promising the thermal performance and possibly also structural integr ity of the tanks. Therefore an Non-destructive Testing (NDT) method for measuring the perlite density or void fraction is urgently needed. Methods based on neutrons are good candidates because they can readil y penetrate through the 1.75 cm outer steel shell and through the ent ire 120 cm thickness of the perlite zone. Neutrons interact with the nuclei of materials to produce characteristic gamma rays which are the n detected. The gamma ray signal strength is proportional to the atom ic number density. Consequently, if the perlite is compacted then the count rates in the individual peaks in the gamma ray spectrum will i ncrease. Perlite is a feldspathic volcanic rock made up of the major elements Si, AI, Na, K and 0 along with some water. With commercially available portable neutron generators it is possible to produce simul taneously fluxes of neutrons in two energy ranges: fast (14 MeV) and thermal (25 meV). Fast neutrons produce gamma rays by inelastic scatt ering which is sensitive to Fe and O. Thermal neutrons produce gamma rays by radiative capture in prompt gamma neutron activation (PGNA) and this is sensitive to Si, AI, Na, Kand H. Thus the two energy ranges produce complementary information. The R&D program has three phases: numerical simulations of neutron and gamma ray transport with MCNP s oftware, evaluation of the system in the laboratory on test articles and finally mapping of the perlite density in the cryogenic tanks at KSC. The preliminary MCNP calculations have shown that the fast/therma l neutron NDT method is capable of distinguishing between expanded an d compacted perlite with excellent statistics.

  17. 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.

  18. 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)

  19. Study of the air quality in industrial areas of Santa Cruz de Tenerife (Spain) by active biomonitoring with Pseudoscleropodium purum.

    Science.gov (United States)

    Ares, Ángela; Fernández, Jose Ángel; Aboal, Jesús Ramón; Carballeira, Alejo

    2011-03-01

    A biomonitoring technique with terrestrial moss transplants (50 sampling sites in a regular grid) was used in an area of the city of Santa Cruz de Tenerife, close to an oil refinery and to an area of dense road traffic for a period of 2 months. The concentration of metals and metalloids (As, Cd, Hg, Ni, Pb and V) and 16 polycyclic aromatic hydrocarbons (PAHs) were determined. The density distribution was represented, the enrichment factors calculated and multifactorial analysis applied. In addition, contamination maps were elaborated on the basis of the bioconcentration obtained, and after confirming the existence of spatial structure, the response surfaces were represented. The results showed very high levels of contamination by Ni and V in the study area, with similar dispersal patterns observed for both. The concentrations of Cd, Hg, Pb and PAHs were lower. Active biomonitoring with terrestrial mosses was found to be a suitable technique for implementing inexpensive environmental monitoring programmes in urban and industrialized areas.

  20. Study of Associated α Particle Imaging Technique for Explosives Detection

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The explosive detecting technique about neutron mainly include the thermal neutron analysis (TNA), the fast neutron analysis (FNA), the pulse fast and thermal neutron analysis (PFTNA) and the associated α particle imaging technique about fast neutron (API).

  1. Polarized Neutron Scattering

    OpenAIRE

    Roessli, B.; Böni, P.

    2000-01-01

    The technique of polarized neutron scattering is reviewed with emphasis on applications. Many examples of the usefulness of the method in various fields of physics are given like the determination of spin density maps, measurement of complex magnetic structures with spherical neutron polarimetry, inelastic neutron scattering and separation of coherent and incoherent scattering with help of the generalized XYZ method.

  2. Broadband Neutron Interferometer

    CERN Document Server

    Pushin, Dmitry A; Hussey, Dan; Miao, Houxun; Arif, Muhammad; Cory, David G; Huber, Michael G; Jacobson, David; LaManna, Jacob; Parker, Joseph D; Shinohara, Taken; Ueno, Wakana; Wen, Han

    2016-01-01

    We demonstrate a two phase-grating, multi-beam neutron interferometer by using a modified Ronchi setup in a far-field regime. The functionality of the interferometer is based on the universal \\moire effect that was recently implemented for X-ray phase-contrast imaging in the far-field regime. Interference fringes were achieved with monochromatic, bichromatic, and polychromatic neutron beams; for both continuous and pulsed beams. This far-field neutron interferometry allows for the utilization of the full neutron flux for precise measurements of potential gradients, and expands neutron phase-contrast imaging techniques to more intense polycromatic neutron beams.

  3. Grazing Incidence Neutron Optics

    Science.gov (United States)

    Gubarev, Mikhail V. (Inventor); Ramsey, Brian D. (Inventor); Engelhaupt, Darell E. (Inventor)

    2013-01-01

    Neutron optics based on the two-reflection geometries are capable of controlling beams of long wavelength neutrons with low angular divergence. The preferred mirror fabrication technique is a replication process with electroform nickel replication process being preferable. In the preliminary demonstration test an electroform nickel optics gave the neutron current density gain at the focal spot of the mirror at least 8 for neutron wavelengths in the range from 6 to 20.ANG.. The replication techniques can be also be used to fabricate neutron beam controlling guides.

  4. 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. ...

  5. Imaging with Scattered Neutrons

    OpenAIRE

    Ballhausen, H.; Abele, H.; Gaehler, R.; Trapp, M; Van Overberghe, A.

    2006-01-01

    We describe a novel experimental technique for neutron imaging with scattered neutrons. These scattered neutrons are of interest for condensed matter physics, because they permit to reveal the local distribution of incoherent and coherent scattering within a sample. In contrast to standard attenuation based imaging, scattered neutron imaging distinguishes between the scattering cross section and the total attenuation cross section including absorption. First successful low-noise millimeter-re...

  6. 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.

  7. Neutron-emission measurements at a white neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Haight, Robert C [Los Alamos National Laboratory

    2010-01-01

    Data on the spectrum of neutrons emittcd from neutron-induced reactions are important in basic nuclear physics and in applications. Our program studies neutron emission from inelastic scattering as well as fission neutron spectra. A ''white'' neutron source (continuous in energy) allows measurements over a wide range of neutron energies all in one experiment. We use the tast neutron source at the Los Alamos Neutron Science Center for incident neutron energies from 0.5 MeV to 200 MeV These experiments are based on double time-of-flight techniques to determine the energies of the incident and emitted neutrons. For the fission neutron measurements, parallel-plate ionization or avalanche detectors identify fission in actinide samples and give the required fast timing pulse. For inelastic scattering, gamma-ray detectors provide the timing and energy spectroscopy. A large neutron-detector array detects the emitted neutrons. Time-of-flight techniques are used to measure the energies of both the incident and emitted neutrons. Design considerations for the array include neutron-gamma discrimination, neutron energy resolution, angular coverage, segmentation, detector efficiency calibration and data acquisition. We have made preliminary measurements of the fission neutron spectra from {sup 235}U, {sup 238}U, {sup 237}Np and {sup 239}Pu. Neutron emission spectra from inelastic scattering on iron and nickel have also been investigated. The results obtained will be compared with evaluated data.

  8. Neutron monitoring for radiological protection

    International Nuclear Information System (INIS)

    Neutron monitoring is a subject of increasing general interest and considerable attention is being paid to the development of improved techniques and methods for neutron monitoring. The Agency, therefore, considered it important to prepare a guide on the subject of neutron monitoring for radiation protection purposes. The present Manual is intended for those persons or authorities in Member States, particularly developing countries, who are responsible for the organization of neutron monitoring programmes and practical neutron monitoring. This Manual consequently, deals with topics such as neutron dosimetry, sources of neutrons and neutron detection as well as field instruments and operational systems used in this context

  9. 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.

  10. Dosimetric evaluation of the Fricke gel dosimeter using the spectrophotometric technique for application in electron and neutron dosimetry; Avaliacao dosimetrica da solucao Fricke gel usando a tecnica de espectrofotometria para aplicacao na dosimetria de eletrons e neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Mangueira, Thyago Fressatti [Instituto de Pesquisas Energeticas e Nucleares (GMR/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Metrologia das Radiacoes

    2011-07-01

    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 thermal neutron field were also evaluated for application in Boron Neutron Capture Therapy (BNCT) and industrial electron fields. The standard reading technique was the spectrophotometry. For clinical fields the intra and inter-batch reproducibility of FXG solution are better than 1.4% and 5.1%, respectively. The optical response presents a linear behavior for doses ranging from 0.2 to 40 Gy independently of the electron 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. The behavior of the dose-response curve does not change the obtained absorbance values relative to the non-irradiated dosimeter response during the studied period. The dose-response curve to industrial electron beam presented an exponential decreasing behavior. The optical response to thermal neutrons beam presented a linear behavior for the studied dose range. According to the obtained results to the different radiation fields studied it was not observed changes in the wavelength of the typical bands of the absorption spectrum radiation induced. Additional tests were performed with FXG solution to verify the viability and application of FXG dosimetry on intracavitary brachytherapy using digital photographic imaging. The excellent performance of the FXG dosimeter indicates that this dosimeter may be applied to tri-dimensional dose evaluation in radiotherapy treatments using electrons and neutron beams. (author)

  11. Dosimetric evaluation of the Fricke gel dosimeter using the spectrophotometric technique for application in electron and neutron dosimetry; Avaliacao dosimetrica da solucao Fricke gel usando a tecnica de espectrofotometria para aplicacao na dosimentria de eletrons e neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Mangueira, Thyago Fressatti

    2009-07-01

    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. 用铀裂变室研究反射中子测量技术%Study on technique for measuring reflection neutrons byuranium fission chamber

    Institute of Scientific and Technical Information of China (English)

    刘荣; 林理彬; 王大伦; 励义俊; 蒋励; 王玫; 刘成龙; 杨可

    2000-01-01

    In a cement shielding designed by ourselves, technique for measuring reflection neutrons was studied by using the depleted and enriched uranium fission chambers. In different experiment systems, absolute fission reaction rates, derived from reflection neutrons, at different positions of the surface of an iron spherical shell were measured. The experimental error was about 3.5%4.1%%在自行设计的水泥屏蔽体中,用铀裂变室研究了反射中子测量技术。在不同实验系统上,测量了铁球壳表面不同位置上中子引起的绝对裂变反应率分布。实验总误差为3.9%。

  13. Development, improvement and calibration of neutronic reaction rate measurements: elaboration of a base of standard techniques; Developpement, amelioration et calibration des mesures de taux de reaction neutroniques: elaboration d`une base de techniques standards

    Energy Technology Data Exchange (ETDEWEB)

    Hudelot, J.P

    1998-06-19

    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 (UO{sub 2}) 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 {sup 238}U (defined as the ratio of {sup 238}U 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 {sup 242}Pu (on MOX rods) and

  14. Applications of some non destructive testing techniques to the characterization of calcareous rocks: ultrasounds, X and gamma-ray radiography, tomography, neutron radiography

    International Nuclear Information System (INIS)

    NUCLEART Laboratory has been developping various techniques of conservation of art objects made of wood or stone. It has, among others, achieved a technique of strengthening porous stone objects, by resin impregnation followed by polymerization under gamma rays. The good conduct of such operations implies the existence of characterization means, before and after treatment of the objects. Two means of rocks characterization have been studied: - ultrasound techniques, - radiography techniques. The first part consists in a general description of the calcareous rocks morphology and a presentation of the studied specimens. The second part deals with the application of ultrasound techniques to rocks. Experimentally, one pays particular attention to the specific aspects of ultrasounds propagation inside materials like porous rocks, and especially diffusion phenomena. Results were interpreted in terms of propagation medium structure. Practical interest for rocks control through such techniques has been underligned. The third part concerns the application of radiographic techniques to calcareous rocks. Experimental work consists in establishing exposure curves for a wide range of energy, and the images quality determination. Through a statistics approach, and using digitalization techniques, one has done an exhaustive study of the radiographic noise. Moreover two techniques close to conventional radiography were explored: neutron radiography and X-ray tomography. Their specificity and interest in the case of calcareous rocks have been shown

  15. FOREWORD: Neutron metrology Neutron metrology

    Science.gov (United States)

    Thomas, David J.; Nolte, Ralf; Gressier, Vincent

    2011-12-01

    industry, from the initial fuel enrichment and fabrication processes right through to storage or reprocessing, and neutron metrology is clearly important in this area. Neutron fields do, however, occur in other areas, for example where neutron sources are used in oil well logging and moisture measurements. They also occur around high energy accelerators, including photon linear accelerators used for cancer therapy, and are expected to be a more serious problem around the new hadron radiation therapy facilities. Roughly 50% of the cosmic ray doses experienced by fliers at the flight altitudes of commercial aircraft are due to neutrons. Current research on fusion presents neutron metrology with a whole new range of challenges because of the very high fluences expected. One of the most significant features of neutron fields is the very wide range of possible neutron energies. In the nuclear industry, for example, neutrons occur with energies from those of thermal neutrons at a few meV to the upper end of the fission spectrum at perhaps 10 MeV. For cosmic ray dosimetry the energy range extends into the GeV region. This enormous range sets a challenge for designing measuring devices and a parallel challenge of developing measurement standards for characterizing these devices. One of the major considerations when deciding on topics for this special issue was agreeing on what not to include. Modelling, i.e. the use of radiation transport codes, is now a very important aspect of neutron measurements. These calculations are vital for shielding and for instrument design; nevertheless, the topic has only been included here where it has a direct bearing on metrology and the development of standards. Neutron spectrometry is an increasingly important technique for unravelling some of the problems of dose equivalent measurements and for plasma diagnostics in fusion research. However, this topic is at least one step removed from primary metrology and so it was felt that it should not be

  16. Basic neutronics. Neutrons migration

    International Nuclear Information System (INIS)

    This article presents the basic neutronics necessary for the understanding of the operation of the different types of nuclear reactors: 1 - introduction to neutronics: principle of fission chain reactions, fast neutron reactors and thermal neutron reactors, capture, neutron status, variations with the reactor lattices; 2 - Boltzmann equation: neutrons population, neutrons migration, characterization of neutrons population and reactions, integral form of the Boltzmann equation, integral-differential form, equivalence between the two forms; 3 - reactor kinetics: fast neutrons and delayed neutrons, kinetic equations in punctual model, Nordheim equation, reactivity jumps, reactivity ramp; 4 - diffusion equation: local neutron status, Fick's law, diffusion equation, initial, boundary and interface conditions, nuclei in infinite and homogenous medium, some examples of solutions, developments in Eigenmodes; 5 - one-group theory: equation of the 'one-group - diffusion' theory, critical condition of the naked and homogenous reactor, critical condition of a reactor with reflectors, generalizations; 6 - neutrons moderation: different moderation mechanisms, elastic shock laws, moderation equation, some examples of solutions; 7 - resonance absorption of neutrons: advantage of the discontinuous moderation character, advantage of an heterogenous disposition, classical formula of the anti-trap factor in homogenous and heterogenous situation; 8 - neutrons thermalization: notions of thermalization mechanisms, thermalization equation, Maxwell spectrum, real spectrum, classical formula of the thermal utilisation factor, classical formula of the reproduction factor, moderation optimum. (J.S.)

  17. Application of digital zero-crossing technique for neutron-gamma discrimination in liquid organic scintillation detectors

    OpenAIRE

    Nakhostin, M; Walker, PM

    2010-01-01

    An algorithm for digital implementation of the zero-crossing method for n/γ discrimination in liquid organic scintillators is described. The method exhibits good performance at low energies and requires little computational effort, which makes it suitable for compact real-time neutron detectors.

  18. Observation of Oxygen Frenkel Disorder in Uranium Dioxide above 2000 K by Use of Neutron-Scattering Techniques

    DEFF Research Database (Denmark)

    Clausen, Kurt Nørgaard; Hayes, W.; Macdonald, J E.;

    1984-01-01

    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...

  19. Development of ionization technique for measurement of fast neutron induced fission products yields of {sup 237}Np

    Energy Technology Data Exchange (ETDEWEB)

    Goverdovski, A.A.; Khryachkov, V.A.; Ketlerov, V.V.; Mitrofanov, V.F.; Ostapenko, Yu.B.; Semenova, N.N.; Fomichev, A.N.; Rodina, L.F. [Institute of Physics and Power Engineering, Obninsk (Russian Federation)

    1997-03-01

    Twin gridded ionization chamber and corresponding software was designed for measurements of masses, kinetic energies and nuclear charges of fission fragments from fast neutron induced fission of {sup 237}Np. The ionization detector design, electronics, data acquisition and processing system and the test results are presented in this paper. (J.P.N.)

  20. Harmonization of health related environmental measurements using nuclear and isotopic techniques. Proceedings of an international symposium

    International Nuclear Information System (INIS)

    One of the particular strengths of nuclear methods is in analytical quality assurance, including the validation of analytical methods and the development of new analytical reference materials. These methodologies are therefore helping to harmonize the data produced not only by nuclear techniques themselves, but also by other non-nuclear methods of analysis. The aim of this symposium was to provide an international forum for discussion of these topics. Its programme covered a wide variety of applications of nuclear (and related) analytical techniques (mainly neutron activation analysis, energy dispersive X ray fluorescence, particle induced X ray emission and inductively coupled plasma-mass spectrometry) as used in the study of air particulates, solid waste products, sediments, food, water, human tissues, biomonitors and other kinds of environmental samples

  1. neutron radiography

    International Nuclear Information System (INIS)

    Neutron radiography (or radiology) is a diverse filed that uses neutrons of various energies, subthermal, thermal, epithermal or fast in either steady state or pulsed mode to examine objects for industrial, medical, or other purposes, both microscopic and macroscopic. The applications include engineering design, biological studies, nondestructive inspection and materials evaluation. In the past decade, over 100 different centers in some 30 countries have published reports of pioneering activities using reactors, accelerators and isotopic neutron sources. While film transparency and electronic video are most common imaging methods for static or in motion objects respectively, there are other important data gathering techniques, including track etch, digital gauging and computed tomography. A survey of the world-wide progress shows the field to be gaining steadily in its diversity, its sophistication and its importance. (author)

  2. 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

  3. Fundamental physics research and neutron interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Ioffe, A. [Hahn-Meitner-Institut Berlin GmbH (Germany)

    1996-08-01

    The possibility of the use of an extremely sensitive neutron interferometry technique for the study of electromagnetic structure of the neutron and the parity non-conservative effects in neutron spin rotation is discussed. (author)

  4. 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.

  5. Some experiments using preconditioning techniques and second-order iterative methods for the resolution of the 3D transient neutron diffusion equation

    International Nuclear Information System (INIS)

    We present a numerical study about the application of two versions of a second-degree iterative method for the solution of the sparse linear systems arising in the discretization of the 3D multi-group time-dependent Neutron Diffusion Equation. In addition, we propose some modifications to them, as well as a study of well-known preconditioning techniques in order to improve their convergence and accuracy when they are applied to a sequence of solutions in time of a real nuclear core transient. This is important for studies of stability and security of nuclear reactors. (authors)

  6. Development of 239Pu total cross section multilevel parameters determination technique by analysing experiments on neutron transmission in resolved resonance region

    International Nuclear Information System (INIS)

    The aim of this work is development of S-matrix multilevel resonance parameters determination technique with neutron transmission data used in resolved resonance region. Experimental transmission data values were obtained for the Pu-239 thickness range 0.00217-0.1234 nucl/barns on the time-of-flight spectrometer with 70 ns/m resolution. S-matrix Adler's formalism with least square method fit were used for experimental data description. The method developed enables to justify the resonance-resonance interference parameters H. Its possibilities are demonstrated by determination of these parameters for four resonances of the Pu-239 total cross section

  7. Characterization of duplex stainless steels by TEM [transmission electron microscopy], SANS [small-angle neutron scattering], and APFIM [atom-probe field ion microscopy] techniques

    International Nuclear Information System (INIS)

    Results are presented of complementary characterization of aged duplex stainless steels by advanced metallographic techniques, including transmission and high-voltage electron microscopies; small-angle neutron scattering; and atom-probe field ion microscopy. On the basis of the characterization, the mechanisms of aging embrittlement have been shown to be associated with the precipitation of Ni- and Si-rich G phase and Cr-rich α' in the ferrite, and M23C6 carbides on the austenite-ferrite phase boundaries. 19 refs., 19 figs., 1 tab

  8. Spatial and temporal mapping of 10B distrubtion in vivo using nuclear reactor-based prompt gamma neutron activation analysis and image reconstruction techniques. Final Report

    International Nuclear Information System (INIS)

    This project involved the development of a method for in vivo prompt gamma neutron activation analysis for the investigation of Boron-10 distribution in a rabbit knee. The overall objective of this work was a robust approach for rapid screening of new 10B-labelled compounds to determine their suitability for use in the treatment of rheumatoid arthritis via Boron Neutron Capture Synovectomy (BNCS). For BNCS it is essential to obtain a compound showing high uptake levels in the synovium and long residence time in the joints. Previously the in vivo uptake behavior of potential compounds was evaluated in the arthritic knee joints of rabbits via extensive dissection studies. These studies are very labor-intensive and involve sacrificing large numbers of animals. An in vivo 10B screening approach was developed to provide initial evaluation of potential compounds. Only those compounds showing positive uptake and retention characteristics will be evaluated further via dissection studies. No further studies will be performed with compounds showing rapid clearance and/or low synovial uptake. Two approaches to in vivo screening were investigated using both simulation methods and experimentation. Both make use of neutron beams generated at the MIT Research Reactor. The first, Transmission Computed Tomography (TCT) was developed and tested but was eventually rejected due to very limited spatial resolution using existing reactor beams. The second, in vivo prompt gamma neutron activation analysis (IVPGNAA) was much more promising. IVPGNAA was developed using computer simulation and physical measurement coupled with image reconstruction techniques. The method was tested in arthritic New Zealand rabbits previously injected intra-articularly with three boron labeled compounds and shown to be effective in providing information regarding uptake level and residence time of 10B in the joint

  9. Neutron scatter camera

    Science.gov (United States)

    Mascarenhas, Nicholas; Marleau, Peter; Brennan, James S.; Krenz, Kevin D.

    2010-06-22

    An instrument that will directly image the fast fission neutrons from a special nuclear material source has been described. This instrument can improve the signal to background compared to non imaging neutron detection techniques by a factor given by ratio of the angular resolution window to 4.pi.. In addition to being a neutron imager, this instrument will also be an excellent neutron spectrometer, and will be able to differentiate between different types of neutron sources (e.g. fission, alpha-n, cosmic ray, and D-D or D-T fusion). Moreover, the instrument is able to pinpoint the source location.

  10. Characterization of neutrons from a thick target {sup 9}Be(p,n) reaction by multiple foil activation technique for practical applications. Measurement of integral cross sections and their comparison with integrated data from data files

    Energy Technology Data Exchange (ETDEWEB)

    Shuza Uddin, M. [Institute of Nuclear Science and Technology (INST), Dhaka (Bangladesh). Atomic Energy Research Establishment; Kume, Kyo; Takata, Takushi [The Wakasa Wan Energy Research Center, Fukui (Japan); Hasegawa, Takashi [Hasetech, Fukui (Japan)

    2014-07-01

    The neutron spectrum in the energy range of 0.1 to 5.85 MeV in the 0 direction with respect to the incident proton beam accelerated in a Tandem Accelerator of the Wakasa Wan Energy Research Center (WERC), Japan, has been characterized using the multiple foil activation technique. Flux mapping of thermal and epithermal neutrons at 0 , 20 , 40 and 60 at downstream of the beam has also been carried out. The fast neutron spectrum averaged cross sections of several threshold reactions were measured. Two monitor reactions, {sup 58}Ni(n,p){sup 58}Co and {sup 115}In(n,n',γ){sup 115m}In, were used to determine the fast neutron flux. The use of fast neutron flux in validating some excitation functions is described. (orig.)

  11. Residual stress in a laser welded EUROFER blanket module assembly using non-destructive neutron diffraction techniques

    CERN Document Server

    Hughes, D J; Heeley, E L

    2014-01-01

    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.

  12. 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.

  13. [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

  14. Advances in neutron tomography

    Indian Academy of Sciences (India)

    W Treimer

    2008-11-01

    In the last decade neutron radiography (NR) and tomography (NCT) have experienced a number of improvements, due to the well-known properties of neutrons interacting with matter, i.e. the low attenuation by many materials, the strong attenuation by hydrogenous constituent in samples, the wavelength-dependent attenuation in the neighbourhood of Bragg edges and due to better 2D neutron detectors. So NR and NCT were improved by sophisticated techniques that are based on the attenuation of neutrons or on phase changes of the associated neutron waves if they pass through structured materials. Up to now the interaction of the neutron spin with magnetic fields in samples has not been applied to imaging techniques despite the fact that it was proposed many years ago. About ten years ago neutron depolarization as imaging signal for neutron radiography or tomography was demonstrated and in principle it works. Now one can present much improved test experiments using polarized neutrons for radiographic imaging. For this purpose the CONRAD instrument of the HMI was equipped with polarizing and analysing benders very similar to conventional scattering experiments using polarized neutrons. Magnetic fields in different coils and in samples (superconductors) at low temperatures could be visualized. In this lecture a summary about standard signals (attenuation) and the more `sophisticated' imaging signals as refraction, small angle scattering and polarized neutrons will be given.

  15. Retrospective environmental biomonitoring - Mussel Watch expanded

    Science.gov (United States)

    Schöne, Bernd R.; Krause, Richard A.

    2016-09-01

    its chemical composition is controlled by the soft parts and that a robust interpretation of the shell record requires a detailed understanding of bivalve physiology, behavior and ecology. This review attempts to bring together the Mussel Watch and sclerochronology communities and lay the foundation of a new subdiscipline of the Mussel Watch: retrospective environmental biomonitoring. For this purpose, we provide an overview of seminal work from both fields and outline potential future research directions.

  16. Determination of silver, gold, zinc and copper in mineral samples by various techniques of instrumental neutron activation analysis; Determinacion de plata, oro, zinc y cobre en muestras minerales mediante diversas tecnicas de analisis por activacion de neutrones instrumental

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez R, N. I.; Rios M, C.; Pinedo V, J. L. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Yoho, M.; Landsberger, S., E-mail: neisla126@hotmail.com [University of Texas at Austin, Nuclear Engineering Teaching Laboratory, Austin 78712, Texas (United States)

    2015-09-15

    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 {sup 110}Ag. 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 {sup 199}Au and 438.6 keV of metastable radionuclide {sup 69m}Zn. On the other hand, copper quantification was based on the photo peak analysis of 1039.2 keV produced by the short half-life radionuclide {sup 66}Cu, 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

  17. Neutron reflectometry

    DEFF Research Database (Denmark)

    Klösgen-Buchkremer, Beate Maria

    2014-01-01

    Neutron (and X-ray) reflectometry constitute complementary interfacially sensitive techniques that open access to studying the structure within thin films of both soft and hard condensed matter. Film thickness starts oxide surfaces on bulk substrates, proceeding to (pauci-)molecular layers and up...... to hundreds of nanometers. Thickness resolution for flat surfaces is in the range of few Ǻngstrøm, and as a peculiar benefit, the presence and properties of buried interfaces are accessible. Focus here will be on neutron reflectometry, a technique that is unique in applications involving composite organic...... of new material. Understanding self-assembly of 2D-3D nanostructures at surfaces and the related interfaces in layered films is a precondition for the development of tailored tools with distributed functions, like new clothes (self-cleaning surfaces combined with mechanical resistance, low permeability...

  18. Morphology of carbon nanotubes prepared via chemical vapour deposition technique using acetylene: A small angle neutron scattering investigation

    Indian Academy of Sciences (India)

    D Sen; K Dasgupta; J Bahadur; S Mazumder; D Sathiyamoorthy

    2008-11-01

    Small angle neutron scattering (SANS) has been utilized to study the morphology of the multi-walled carbon nanotubes prepared by chemical vapour deposition of acetylene. The effects of various synthesis parameters like temperature, catalyst concentration and catalyst support on the size distribution of the nanotubes are investigated. Distribution of nanotube radii in two length scales has been observed. The number density of the smaller diameter tubes was found more in number compared to the bigger one for all the cases studied. No prominent scaling of the structure factor was observed for the different synthesis conditions.

  19. Representation, testing and assessment of the 'Estelle' formal description technique from a computer-controlled neutron scatter experiment

    International Nuclear Information System (INIS)

    Estelle is a formal method of description, which was developed based on an extended state transition model for the specification of communication records and services. Regardless of the field of application, there are problems common to all systems in distributed systems, i.e. in communication systems as in process computer systems, which are to be specified. These include real time problems, such as waiting for events, reactions to expected events and those occurring at the correct time, reacting to unexpected events or those not occurring at the correct time, transmitting and receiving data and the synchronisation of process going on simultaneously. This work examines, using the example of a process computer-controlled neutron scatter experiment, whether Estelle is suitable for the specification of distributed real time systems in this field of application. (orig.)

  20. Quality control of baby food products on the basis of results obtained using the instrumental neutron-activation analysis technique

    International Nuclear Information System (INIS)

    The purpose of this study was to use the instrumental neutron-activation analysis (INAA) to determine the elemental composition of some kind of imported baby food products (BFP) and to compare the results with the permissible contents. The nuclear reactor WWR-SM of INP has been used to develop INAA to study the mineral composition of some children's food products. The concentration of 26 trace elements, including Mg, Ca, Fe, Zn, etc. was found. The comparison of the results with regulation contents and the daily data on food needs have shown that the investigated group of BFP does not meet the requirements for all trace and macro elements composition. (authors)

  1. Estimation of Th, Cs, Sr, I, Co, Fe, Zn, Ca and K in major food components using neutron activation analysis technique

    International Nuclear Information System (INIS)

    The concentration of some radiologically and nutritionally important trace elements: Th, Cs, Sr, I, Co, Fe, Zn, Ca and K were determined in major food components such as cereals, pulses, vegetables, fruits, milk etc. The trace elements in food samples were determined using neutron activation analysis technique which involves instrumental and radiochemical neutron activation analysis. Whereas, the trace elements Th, Cs, K and Sr, are important in radiation protection; Fe and Zn are of importance in nutrition studies and Ca and I have dual importance, both in nutrition and radiation protection. The results of analysis show that among the food materials, higher concentrations of Th, Cs, Sr, K, Fe, Zn and Co were found in cereals and pulses. In case of Ca, the milk appears to be the main contributor towards its dietary intake. The estimated concentrations of the trace elements in food components can be employed in determining the daily dietary intake of these elements which in turn can be used for their biokinetic studies. (author)

  2. Investigation of mangrove macroalgae as biomonitors of estuarine metal contamination

    Energy Technology Data Exchange (ETDEWEB)

    Melville, Felicity [Department of Environmental Sciences/Institute of Water and Environmental Resource Management, University of Technology, Sydney, PO Box 123, Broadway NSW 2007 (Australia)], E-mail: f.melville@cqu.edu.au; Pulkownik, Alex [Department of Environmental Sciences/Institute of Water and Environmental Resource Management, University of Technology, Sydney, PO Box 123, Broadway NSW 2007 (Australia)

    2007-11-15

    This study examined the potential use of macroalgae epiphytic on mangrove aerial roots as biomonitors of estuarine contamination. The metal concentrations of macroalgae were investigated in four estuaries in the vicinity of Sydney, Australia, and compared to water and sediment metal concentrations over three seasonal surveys. Macroalgal metal concentrations (copper, zinc, cadmium, chromium, lead, nickel, manganese and iron) appeared to be more associated with sediment metal concentrations than water concentrations, suggesting they may be useful biomonitors of estuarine sediment contamination. Algae in the more contaminated estuaries generally contained higher metal concentrations. However, concentrations of iron, nickel and manganese appeared to be similar in the algae despite the varying sediment concentrations, while accumulation of copper, zinc, lead and chromium appeared to be associated with ambient environmental concentrations. The uptake of metals also varied among the different species, suggesting that algal parameters, such as morphology, may also influence metal uptake and accumulation.

  3. Analysis of lichens for use in biomonitoring of environmental pollution; Analise de liquens para uso na biomonitoracao da poluicao ambiental

    Energy Technology Data Exchange (ETDEWEB)

    Horimoto, Lidia K.; Saiki, Mitiko; Vasconcellos, Marina B.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Supervisao de Radioquimica; Marcelli, Marcello P. [Instituto de Botanica, Sao Paulo, SP (Brazil). Secao de Micologia e Liquenologia

    2000-07-01

    This work presents the results of Al, As, Br, Ca, Cd, Cl, Co, Cs, Fe, K, Mg, Mn, Na, Rb, Se, Th, V and Zn obtained by instrumental neutron activation analysis in the analyses of epiphytic lichen samples collected in different sites of the States of Sao Paulo and Parana. These lichens were collected in the following sites: Cidade Universitaria, Campo Limpo Paulista, Sao Bernardo do Campo and Itanhaen situated in the State of Sao Paulo and one sample was from Vila Velha, Ponta Grossa of Parana State. The purpose of these analyses were to obtain preliminary information of air quality of these regions and also select a region of interest for biomonitoring studies. (author)

  4. Algae as Bio-monitors for Damodar River Water Pollution

    OpenAIRE

    S. Lata Dora; Maiti, S. K.; R. K.Tiwary; Anshumali Singh

    2015-01-01

    Damodar is an important tributary of Ganga river basin and cater the needs of industries and growing human population in the eastern part of India. Assessment of algal diversity was carried out to understand the impact of coal mining and allied industrial activities on the ecological condition of Damodar river basin. Surface water and algal samples were collected in the summer (2009) from ten sites along the Damodar River. Bio-monitoring of algal diversity showed high organic pollution load i...

  5. Applicability of non-invasively collected matrices for human biomonitoring

    Directory of Open Access Journals (Sweden)

    Nickmilder Marc

    2009-03-01

    Full Text Available Abstract With its inclusion under Action 3 in the Environment and Health Action Plan 2004–2010 of the European Commission, human biomonitoring is currently receiving an increasing amount of attention from the scientific community as a tool to better quantify human exposure to, and health effects of, environmental stressors. Despite the policy support, however, there are still several issues that restrict the routine application of human biomonitoring data in environmental health impact assessment. One of the main issues is the obvious need to routinely collect human samples for large-scale surveys. Particularly the collection of invasive samples from susceptible populations may suffer from ethical and practical limitations. Children, pregnant women, elderly, or chronically-ill people are among those that would benefit the most from non-invasive, repeated or routine sampling. Therefore, the use of non-invasively collected matrices for human biomonitoring should be promoted as an ethically appropriate, cost-efficient and toxicologically relevant alternative for many biomarkers that are currently determined in invasively collected matrices. This review illustrates that several non-invasively collected matrices are widely used that can be an valuable addition to, or alternative for, invasively collected matrices such as peripheral blood sampling. Moreover, a well-informed choice of matrix can provide an added value for human biomonitoring, as different non-invasively collected matrices can offer opportunities to study additional aspects of exposure to and effects from environmental contaminants, such as repeated sampling, historical overview of exposure, mother-child transfer of substances, or monitoring of substances with short biological half-lives.

  6. Environmental lichenology: Biomonitoring trace-element air pollution. Doctoral thesis

    Energy Technology Data Exchange (ETDEWEB)

    Sloof, J.E.

    1993-09-27

    In this thesis several experiments have been described on the applicability of lichens as biomonitors for trace-element air pollution. The aim of the thesis was to gain knowledge about the relationships between trace-element concentrations in lichens and concentrations in air particulate matter and/or depositions of trace elements on a regional and national scale, and about the processes involved in the element uptake and release by lichens. (Copyright (c) 1993 by J.E. Sloof.)

  7. Analgesic use - prevalence, biomonitoring and endocrine and reproductive effects

    DEFF Research Database (Denmark)

    Kristensen, David Møbjerg; Mazaud-Guittot, Sverine; Gaudriault, Pierre;

    2016-01-01

    policies, habits, accessibility, disease patterns and the age distribution of each population. Biomonitoring indicates ubiquitous and high human exposure to paracetamol and to salicylic acid, which is the main metabolite of acetylsalicylic acid. Furthermore, evidence suggests that analgesics can have......Paracetamol and NSAIDs, in particular acetylsalicylic acid (aspirin) and ibuprofen, are among the most used and environmentally released pharmaceutical drugs. The differences in international trends in the sale and consumption of mild analgesics reflect differences in marketing, governmental...

  8. Study on two-phase flow in a coolant channel of a plate-type fuel with use of neutron radiography technique

    International Nuclear Information System (INIS)

    Two-phase flow in a narrow rectangular duct is important related to abnormal cooling conditions of a MTR type research reactor. In view of this, flow regime, void fraction, slug bubble velocity and pressure loss were measured for rectangular ducts with a narrow gap. The neutron radiography technique was used to visualize the flow and the void fraction was obtained by image processing. The void fraction was correlated well by the drift flux model with existing correlation for the distribution parameter which was about 1.35. Similar results were obtained for slug bubble velocity, however the distribution parameter was in the range from 1.0 to 1.2. The frictional pressure loss was correlated well by the Chisholm-Laird correlation. In collaboration with previously obtained data, it was found that the Chisholm's parameter C, however, changed from 21 to zero as the gap decreased. (author)

  9. Characterization of ancient glass excavated in Enez (Ancient Ainos) Turkey by combined Instrumental Neutron Activation Analysis and Fourier Transform Infrared spectrometry techniques

    Science.gov (United States)

    Akyuz, Sevim; Akyuz, Tanil; Mukhamedshina, Nuranya M.; Mirsagatova, A. Adiba; Basaran, Sait; Cakan, Banu

    2012-05-01

    Ancient glass fragments excavated in the archaeological district Enez (Ancient Ainos)-Turkey were investigated by combined Instrumental Neutron Activation Analysis (INAA) and Fourier Transform Infrared (FTIR) spectrometry techniques. Multi-elemental contents of 15 glass fragments that belong to Hellenistic, Roman, Byzantine, and Ottoman Periods, were determined by INAA. The concentrations of twenty six elements (Na, K, Ca, Sc, Cr, Mn, Fe, Co, Cu, Zn, As, Rb, Sr, Sb, Cs, Ba, Ce, Sm, Eu, Tb, Yb, Lu, Hf, Ta, Au and Th), which might be present in the samples as flux, stabilizers, colorants or opacifiers, and impurities, were examined. Chemometric treatment of the INAA data was performed and principle component analysis revealed presence of 3 distinct groups. The thermal history of the glass samples was determined by FTIR spectrometry.

  10. Terrestrial mosses as biomonitors of atmospheric POPs pollution: A review

    International Nuclear Information System (INIS)

    Worldwide there is concern about the continuing release of persistent organic pollutants (POPs) into the environment. In this study we review the application of mosses as biomonitors of atmospheric deposition of POPs. Examples in the literature show that mosses are suitable organisms to monitor spatial patterns and temporal trends of atmospheric concentrations or deposition of POPs. These examples include polycyclic aromatic hydrocarbons (PAHs), polychlorobiphenyls (PCBs), dioxins and furans (PCDD/Fs), and polybrominated diphenyl ethers (PBDEs). The majority of studies report on PAHs concentrations in mosses and relative few studies have been conducted on other POPs. So far, many studies have focused on spatial patterns around pollution sources or the concentration in mosses in remote areas such as the polar regions, as an indication of long-range transport of POPs. Very few studies have determined temporal trends or have directly related the concentrations in mosses with measured atmospheric concentrations and/or deposition fluxes. - Highlights: ► Terrestrial mosses are suitable organisms to monitor deposition of POPs. ► They provide a good indication of spatial patterns and temporal trends. ► Mosses have been used as biomonitors of PAHs, PCBs, PBDEs dioxins and furans. ► Few studies have assessed the relationship between concentrations in air and mosses. - Mosses are suitable biomonitors of persistent organic pollutants (POPs).

  11. Manila clam Venerupis philippinarum as a biomonitor to metal pollution

    Institute of Scientific and Technical Information of China (English)

    WU Huifeng; JI Chenglong; WANG Qing; LIU Xiaoli; ZHAO Jianmin; FENG Jianghua

    2013-01-01

    The Manila clam Venerupis philippinarum is a good biomonitor/bioindicator to marine metal pollution and is frequently used in aquatic toxicology.Two dominant pedigrees (white and zebra) of clam are distributed in the Bohai Sea; however,little attention has been paid to potential biological differences between these two pedigrees.In this study,we tested the sensitivity of both pedigrees to marine metal (cadmium and zinc) pollution biomonitoring and marine environmental toxicology.Results demonstrate significant biological differences in gills of white and zebra clams based on metabolic profiles and antioxidant enzyme activities.In addition,we found that hypotaurine,malonate and homarine were relatively high in white clam gills,while alanine,arginine,glutamate,succinate,4-aminobutyrate,taurine and betaine were high in zebra clam gills.Zebra clam gills were also more sensitive to a mixture of Cd and Zn,as shown by antioxidant enzyme activities and metabolic profiles,but white clam gills could accumulate more Zn.Therefore,we suggest that the white pedigree can be used as a biomonitor to marine Zn pollution,whereas the zebra pedigree can be used for toxicology studies on Cd and Zn mixed pollution.

  12. Phylogenetic signal in diatom ecology: perspectives for aquatic ecosystems biomonitoring.

    Science.gov (United States)

    Keck, François; Rimet, Frédéric; Franc, Alain; Bouchez, Agnés

    2016-04-01

    Diatoms include a great diversity of taxa and are recognized as powerful bioindicators in rivers. However using diatoms for monitoring programs is costly and time consuming because most of the methodologies necessitate species-level identification. This raises the question of the optimal trade-off between taxonomic resolution and bioassessment quality. Phylogenetic tools may form the bases of new, more efficient approaches for biomonitoring if relationships between ecology and phylogeny can be demonstrated. We estimated the ecological optima of 127 diatom species for 19 environmental parameters using count data from 2119 diatom communities sampled during eight years in eastern France. Using uni- and multivariate analyses, we explored the relationships between freshwater diatom phylogeny and ecology (i.e., the phylogenetic signal). We found a significant phylogenetic signal for many of the ecological optima that were tested, but the strength of the signal varied significantly from one trait to another. Multivariate analysis also showed that the multidimensional ecological niche of diatoms can be strongly related to phylogeny. The presence of clades containing species that exhibit homogeneous ecology suggests that phylogenetic information can be useful for aquatic biomonitoring. This study highlights the presence of significant patterns of ecological optima for freshwater diatoms in relation to their phylogeny. These results suggest the presence of a signal above the species level, which is encouraging for the development of simplified methods for biomonitoring survey. PMID:27411256

  13. Neutron powder diffraction

    International Nuclear Information System (INIS)

    Neutron powder diffraction is a powerful technique that provides a detailed description of moderately complex crystal structures. This is nowhere more apparent than in the area of high temperature superconductors where neutron powder diffraction has provided precise structural and magnetic information, not only under ambient conditions but also at high and low temperatures and high pressures. Outside superconductor research, the variety of materials studied by neutron powder diffraction is equally impressive including zeolites, fast ionic conductors, permanent magnets and materials undergoing phase transitions. Recent advances that include high resolution studies and real-time crystallography are presented. Future possibilities of neutron powder diffraction are discussed

  14. Support for cold neutron utilization

    International Nuclear Information System (INIS)

    - Support for experiments by users of cold neutron scattering instrument - Short-term training of current and potential users of cold neutron scattering instrument for their effective use of the instrument - International collaboration for advanced utilization of cold neutron scattering instruments - Selection and training of qualified instrument scientists for vigorous research endeavors and outstanding achievements in experiments with cold neutron - Research on nano/bio materials using cold neutron scattering instruments - Bulk nano structure measurement using small angle neutron scattering and development of analysis technique

  15. Biomonitoring of Non-Dioxin-Like Polychlorinated Biphenyls in Transgenic Arabidopsis Using the Mammalian Pregnane X Receptor System: A Role of Pectin in Pollutant Uptake

    OpenAIRE

    Bao, Lieming; Gao, Chen; Li, Miaomiao; Chen, Yong; Lin, Weiqiang; Yang, Yanjun; Han, Ning; Bian, Hongwu; Zhu, Muyuan; Wang, Junhui

    2013-01-01

    Polychlorinated biphenyls (PCBs) are persistent organic pollutants damaging to human health and the environment. Techniques to indicate PCB contamination in planta are of great interest to phytoremediation. Monitoring of dioxin-like PCBs in transgenic plants carrying the mammalian aryl hydrocarbon receptor (AHR) has been reported previously. Herein, we report the biomonitoring of non-dioxin-like PCBs (NDL-PCBs) using the mammalian pregnane X receptor (PXR). In the transgenic Arabidopsis desig...

  16. Atmospheric pollution biomonitoring of the Sao Paulo metropolitan region using epiphytic lichens

    International Nuclear Information System (INIS)

    Due to the increasing problems of atmospheric pollution in the Sao Paulo metropolitan region that affect the environment and human health the application of biomonitoring methodologies using cosmopolite organisms has now become relevant. Biomonitoring is a method to evaluate the response of live organisms to pollution. This method offers advantages such as reduced costs, efficient monitoring of large geographic areas and accumulated pollutants over a large period in which low concentrations of chemicals elements in the environment can be evaluated. In the present study, neutron activation analysis method was applied to determine elements accumulated in Canoparmelia texana lichenized fungi. Samples were collected in two distinct areas: Carlos Botelho (PECB) and Intervales (PEI) State Parks that are considered as non-polluted areas and that belong to the Atlantic Forest - SP ecosystem; and Sao Paulo city metropolitan region in sites near automatic monitoring stations of the Environmental Protection Agency of the State of Sao Paulo (CETESB). The lichens collected from the bark of the trees were properly treated, and irradiated with neutrons from IEA-R1 nuclear reactor along with synthetic standards of elements. The precision and the accuracy of the results were evaluated by the analyses of IAEA-336 LICHEN and Mixed Polish Herbs (INCT -MPH-2) certified reference materials. The results obtained for these materials were in accordance with the certified values and presented good precision with variation coefficients ranging from 0.9 to 14.6%. Results obtained for lichens showed that elements As, Co, Cr, Cs, La, Mo, Sb, Sc, Se and U are present at ng g-1 levels, Ba, Br, Cl, Fe, K, Mn, Na, Rb and Zn at μg g-1 and Ca at mg g-1. By applying cluster and discriminant analyses to the results for the lichen samples from areas with different levels of pollution, the sampling sites were grouped according to their chemical similarities and their elemental composition. It was also

  17. Resonance neutron radiography

    International Nuclear Information System (INIS)

    The production of images by the use of neutrons having energies in the resonance region is described. Two-dimensional position-sensitive neutron detectors are used to produce transmission images using neutron time-of-flight techniques at the National Bureau of Standards' electron linac facility. Two types of detectors are described. The first is a crossed-wire proportional counter using 3He as the neutron-sensitive component. The second type utilizes a multichannel plate electron multiplier and a resistive anode readout. A lithium glass scintillator is the neutron-sensitive component in the latter detector. Resonance neutron radiography, using these detectors, has the capability of producing images with isotopic and chemical element discrimination in a complex matrix with a resolution of 1 mm or better. (Auth.)

  18. Human biomonitoring data interpretation and ethics; obstacles or surmountable challenges?

    Directory of Open Access Journals (Sweden)

    Sepai Ovnair

    2008-01-01

    Full Text Available Abstract The use of human samples to assess environmental exposure and uptake of chemicals is more than an analytical exercise and requires consideration of the utility and interpretation of data as well as due consideration of ethical issues. These aspects are inextricably linked. In 2004 the EC expressed its commitment to the development of a harmonised approach to human biomonitoring (HBM by including an action in the EU Environment and Health Strategy to develop a Human Biomonitoring Pilot Study. This further underlined the need for interpretation strategies as well as guidance on ethical issues. A workshop held in December 2006 brought together stakeholders from academia, policy makers as well as non-governmental organisations and chemical industry associations to a two day workshop built a mutual understanding of the issues in an open and frank discussion forum. This paper describes the discussion and recommendations from the workshop. The workshop developed key recommendations for a Pan-European HBM Study: 1. A strategy for the interpretation of human biomonitoring data should be developed. 2. The pilot study should include the development of a strategy to integrate health data and environmental monitoring with human biomonitoring data at national and international levels. 3. Communication strategies should be developed when designing the study and evolve as the study continues. 4. Early communication with stakeholders is essential to achieve maximum efficacy of policy developments and facilitate subsequent monitoring. 5. Member states will have to apply individually for project approval from their National Research Ethics Committees. 6. The study population needs to have sufficient information on the way data will be gathered, interpreted and disseminated and how samples will be stored and used in the future (if biobanking before they can give informed consent. 7. The participants must be given the option of anonymity. This has an impact

  19. Neutron imaging in materials science

    OpenAIRE

    Nikolay Kardjilov; Ingo Manke; André Hilger; Markus Strobl; John Banhart

    2011-01-01

    Neutron imaging is a non-destructive technique that can reveal the interior of many materials and engineering components and also probe magnetic fields. Within the past few years, several new imaging modes have been introduced that extend the scope of neutron imaging beyond conventional neutron attenuation imaging, yielding both 2- and 3D information about properties and phenomena inaccessible until now. We present an overview of the most important advances in the application of neutron imagi...

  20. Nuclear astrophysics with neutrons

    Science.gov (United States)

    Dillmann, I.; Reifarth, R.

    2012-04-01

    Neutrons play a crucial role in astrophysics during the heavy element nucleosynthesis. The largest fraction of isotopes heavier than iron is produced by neutron capture processes on short (r process) and long timescales (s process). During the ``slow neutron capture process'' (s process) heavier elements are produced by successive captures of in-situ produced neutrons from the reactions 13C(α,n)16O and 22Ne(α,n)25Mg (with densities of 106-1010 cm-3) in the interior of stars and following β-decays. With this scenario the reaction path runs along the valley of stability up to 209Bi and produces about 50% of the solar abundances of the heavy elements. Important nuclear physics parameters for s-process nucleosynthesis are neutron capture cross sections (for En = 0.3-300 keV, corresponding to stellar temperatures between kT= 8 and 90 keV) and β-decay half-lives. Neutron capture measurements can be performed via activation in a quasi-stellar neutron spectrum utilizing several (p,n) reactions, or by the time-of-flight technique. The ``rapid neutron capture process'' (r process) is responsible for the remaining 50% of the solar abundances. Here neutrons with densities of 1020-1030 cm-3 are captured on a very fast timescale (ms) during a Core Collapse Supernova in a region close to the forming neutron star. The r-process nuclei are thus very short-lived, neutron-rich isotopes up to the actinides, which can only be produced and investigated at large-scale radioactive-beam facilities. Here the most important nuclear physics parameters are masses, half-lives, and at later stages also β-delayed neutrons. This paper will summarize the role of neutrons in nuclear astrophysics and give a short overview about the related astrophysics programs at the GSI Helmholtz research center and the FRANZ facility in Germany.

  1. 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...

  2. Lessons learnt on recruitment and fieldwork from a pilot European human biomonitoring survey

    DEFF Research Database (Denmark)

    Fiddicke, Ulrike; Becker, Kerstin; Schwedler, Gerda;

    2015-01-01

    Within the European Environment and Health Action Plan an initiative to establish a coherent human biomonitoring approach in Europe was started. The project COPHES (COnsortium to Perform Human biomonitoring on a European Scale ) developed recommendations for a harmonized conduct of a human biomon...

  3. Biomonitoring of toxic compounds of airborne particulate matter in urban and industriel areas

    DEFF Research Database (Denmark)

    Klumpp, Andreas; Ro-Poulsen, Helge

    2010-01-01

    on man and environment. Two widely applied biomonitoring procedures, namely the standardised ryegrass exposure for monitoring of trace metals, and the standardised exposure of curly kale for monitoring of PAH compounds, is presented taking examples from a Europe-wide biomonitoring study conducted in 11...

  4. Analytical solution of the multigroup neutron diffusion kinetic equation in one-dimensional cartesian geometry by the integral transform technique; Solucao analitica da equacao cinetica de difusao multigrupo de neutrons em geometria cartesiana unidimensional pela tecnica da transformada integral

    Energy Technology Data Exchange (ETDEWEB)

    Ceolin, Celina

    2010-07-01

    The objective of this work is to obtain an analytical solution of the neutron diffusion kinetic equation in one-dimensional cartesian geometry, to monoenergetic and multigroup problems. These equations are of the type stiff, due to large differences in the orders of magnitude of the time scales of the physical phenomena involved, which make them difficult to solve. The basic idea of the proposed method is applying the spectral expansion in the scalar flux and in the precursor concentration, taking moments and solving the resulting matrix problem by the Laplace transform technique. Bearing in mind that the equation for the precursor concentration is a first order linear differential equation in the time variable, to enable the application of the spectral method we introduce a fictitious diffusion term multiplied by a positive value which tends to zero. This procedure opened the possibility to find an analytical solution to the problem studied. We report numerical simulations and analysis of the results obtained with the precision controlled by the truncation order of the series. (author)

  5. Magnetic moment of the 2+ state in the neutron-rich radioactive 72Zn using the High-Velocity Transient-Field technique

    International Nuclear Information System (INIS)

    We report the first measurement of the g factor of the first 2+ state of the radioactive neutron-rich nucleus 72Zn using the High-Velocity Transient-Field (HVTF) technique. The neutron-rich N=40 region has long been discussed regarding the competition between single-particle-like structures in the Ni isotopes and the collective states in their immediate vicinity. Nuclear gyromagnetic factors, with their sensitivity to the single-particle properties of the nuclear states, can be one of the most sensitive probes of this interplay. Whereas the g factors of the 2+ states of the stable Ni isotopes show predominantly single particle behavior, consistent with relatively simple shell model structures [1], those of the nearby Zn and Ge isotopes show a trend consistent with the Z/A rule characteristic of collective states [2]. Particular interest in the Zn isotopes comes about because a number of theoretical calculations predict a change from collective to single-particle dominated behavior in the N=40 region. The main difference between the various models is related to the strength of this change and how sudden or gradual it is expected to be. The last known g factor of the stable isotope 70Zn still implies collective behavior. In the present experiment we have applied the HVTF technique for the first time to nuclei with Z>20 and A>40. As has been demonstrated in the previous measurement of this type [3], the technique can provide a very strong transient magnetic field (TF) for ions traversing ferromagnetic layers with velocities ∼Zv0, which in the Z2Zn was produced at GANIL by intermediate-energy projectile fragmentation (∼60 MeV/A) of 76Ge on a 500 μg/cm2 Be target, and selected using the LISE spectrometer. The 2+ state was populated via Coulomb excitation in a secondary Gd target, also used as the ferromagnetic layer for providing the TF. The scattered beam particles were detected in a plastic scintillator in coincidence with gamma-rays registered by 8 EXOGAM

  6. Study of the effect of nano-sized precipitates on the mechanical properties of boron-added low-carbon steels by neutron scattering techniques.

    Science.gov (United States)

    Seong, B S; Cho, Y R; Shin, E J; Kim, S I; Choi, S-H; Kim, H R; Kim, Y J

    2008-10-01

    Small-angle neutron scattering (SANS) and neutron powder diffraction (ND) techniques were used to study quantitatively the effect of nano-sized precipitates and boron addition on the mechanical properties of low-carbon steels. SANS was used to evaluate nano-sized precipitates, smaller than about 600 A in diameter, and ND was used to determine the weight fraction of the cementite precipitates. Fine core-shell structured spherical precipitates with an average radius of ~50 A, such as MnS and/or CuS, surrounded by BN layers were observed in the boron-added (BA) low-carbon steels; fine spherical precipitates with an average radius of ~48 A were mainly observed in the boron-free (BF) low-carbon steels. In the BA steels, the number of boron precipitates, such as BN, Fe(3)(C,B) and MnS, surrounded by BN layers increased drastically at higher hot-rolling temperatures. The volume fraction of the fine precipitates of the BA steels was higher than that of the BF steels; this difference is related to the rapid growth of the BN layers on the MnS and CuS precipitates. Boron addition to low-carbon steels resulted in a reduction in strength and an improvement in elongation; this behaviour is related to the reduction of the solute carbon and the nitrogen contents in the ferrite matrix caused by the precipitation of BN, as well by the increase in the volume fraction of the cementites. PMID:19461851

  7. Application des techniques de diffusion de la lumière des rayons X et des neutrons à l'étude des systèmes colloïdaux. Première partie : Présentation théorique des trois techniques Application of Light, X-Ray and Neutron Diffusion Techniques to the Study of Colloidal Systems. Part One : Theoretical Description of Three Techniques

    OpenAIRE

    Espinat D.

    2006-01-01

    Les techniques de diffusion, des rayons X, des neutrons et de la lumière, jouent un rôle très important pour la compréhension des milieux colloïdaux. Peu d'articles de la littérature s'attachent à présenter conjointement les trois méthodes. Nous avons, dans la première partie de cet article, détaillé les principes théoriques en insistent tout particulièrement sur les spécificités de chacune. Après les rappels concernant la diffusion par les systèmes dilués, nous nous sommes intéressés aux sys...

  8. Investigation of the cyclic techniques in neutron activation analysis on Da Lat research reactor for determination of short-lived radionuclides in biological materials

    International Nuclear Information System (INIS)

    The ability of the sensitivity and precision of Cyclic, Pseudocyclic and Cumulative (Replicate) techniques in neutron activation analysis (NAA) on Dalat research reactor were investigated for the determination of short-lived radionuclides. This research focused on determination of 77mSe (T1/2 = 17.4 seconds) in biological materials as a case in point. The result shows that an improvement of detection limits of approximately 2 times in the 3rd cycle to 4th cycle was obtained by using Cyclic NAA, Pseudocyclic NAA and Cumulative NAA in comparison with conventional NAA. The lower detection limits of approximately 3 times can be obtained by a combination of 3 subsamples in Cumulative NAA and 3 cycles in PCNAA. The precision of the techniques is typically within 2-5% from 2nd to 3rd cycles and afterward. In general, the precision and confidence in representative of the analysis result of Cumulative NAA are better than others. However, the utilization of Cyclic NAA is the most useful as regards analysis time. With reference to analytical sensitivity, Cumulative NAA in combination with CNAA or PCNAA will provide a lowest detection limit, and thereby suiting for determining short-lived radionuclides in biological materials with very low concentration levels. (author)

  9. Shrink tape technique for heat-forming aluminum substrates for thin foil x-ray mirrors and the Neutron Star Interior Composition Explorer x-ray concentrators

    Science.gov (United States)

    Balsamo, Erin; Gendreau, Keith; Okajima, Takashi; Soong, Yang; Serlemitsos, Peter; Jalota, Lalit; Kenyon, Steven; Spartana, Nicholas; Fickau, David; Koenecke, Richard

    2016-01-01

    Consistent improvements in the design and fabrication of thin-foil, epoxy-replicated x-ray mirrors for astronomical telescopes have yielded increasingly higher quality and more precise astrophysical data. The Neutron Star Interior Composition Explorer (NICER) x-ray timing mission optics continues this tradition and introduces design elements that promise even more accurate measurements and precise astrophysical parameters. The singly reflecting concentrators have a curved axial profile to improve photon concentration and a sturdy full shell structure for enhanced module stability. These design elements introduced the challenge of reliably forming mirror substrates at an acceptable production rate. By developing a technique using heat shrink tape to compress and conform thin aluminum mirror substrates to shaping mandrels, production rate improved with successful fabrication. The technique's efficiency was analyzed by measuring hundreds of substrate profiles postforming, performance testing completely assembled concentrators composed of every size substrate, and comparing the results to simulated fabrication scenarios. On average, the profiles were copied within 4.6±3.7%. These measurements and the overall success of NICER's optics, via ground calibration, have shown that the heat-shrink tape method is reliable, repeatable, and could be used in future missions to increase production rate and improve performance.

  10. Biomonitoring in occupational health: Scientific, socio-ethical, and regulatory issues

    International Nuclear Information System (INIS)

    Biomonitoring is one of the best available tools for the prevention of deleterious effects resulting from occupational exposure to chemicals. The availability of analytical techniques having low detection limits allows for the measurement of numerous biomarkers. Complemented with quality control programs, our ability to collect validated information on exposure to toxicants improves. This is important as exposure doses tend to decrease in workplaces. Concurrently, there is an increasing preoccupation towards skin exposure, which cannot currently be reliably assessed through external measurements. Furthermore, as lower exposure doses are encountered, background concentrations of some biomarkers become a serious limitation to their use. This prompts researchers to seek for minor, more specific metabolites, that may however be produced through metabolic pathways that are prone to larger inter-individual variations. Assessment of exposure to complex mixtures of chemicals is another major challenge. There is a growing interest towards ethical issues in biomonitoring. The understanding of the advantages and of the limits of this preventive approach may be very different among occupational health professionals, but more importantly, between health professionals and those they are seeking to protect, i.e., the workers themselves. Many organizations have proposed guideline values for biomarker concentrations, but these seldom find their way in the various countries' bylaws. One underlying reason might be the greater complexity of the scientific aspects of biomarkers, whose understanding is required to set limit values, compared to the process of setting airborne limit concentrations. But the fact that the latter does not consider all aspects of biological complexity does not make it more reliable

  11. Proposal of requirements for performance in Brazil for systems of external individual monitoring for neutrons applying the TLD-albedo technique; Proposta de requisitos de desempenho no Brasil para sistemas de monitoracao individual externa para neutrons empregando a tecnica TLD-albedo

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Marcelo M.; Mauricio, Claudia L.P.; Pereira, Walsan W.; Fonseca, Evaldo S. da, E-mail: marcelo@ird.gov.b, E-mail: claudia@ird.gov.b, E-mail: walsan@ird.gov.b, E-mail: evaldo@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Silva, Ademir X., E-mail: ademir@con.ufrj.b [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil).

    2009-07-01

    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

  12. Oxygen flux as an indicator of physiological stress in aquatic organisms: a real-time biomonitoring system of water quality

    Science.gov (United States)

    Sanchez, Brian C.; Yale, Gowri; Chatni, Rameez; Ochoa-Acuña, Hugo G.; Porterfield, D. Marshall; Mclamore, Eric S.; Sepúlveda, María S.

    2009-05-01

    The detection of harmful chemicals and biological agents in real time is a critical need for protecting water quality. We studied the real-time effects of five environmental contaminants with differing modes of action (atrazine, pentachlorophenol, cadmium chloride, malathion, and potassium cyanide) on respiratory oxygen consumption in 2-day post-fertilization fathead minnow (Pimephales promelas) eggs. Our objective was to assess the sensitivity of fathead minnow eggs using the self-referencing micro-optrode technique to detect instantaneous changes in oxygen consumption after brief exposures to low concentrations of contaminants. Oxygen consumption data indicated that the technique is indeed sensitive enough to reliably detect physiological alterations induced by all contaminants. After 2 h of exposure, we identified significant increases in oxygen consumption upon exposure to pentachlorophenol (100 and 1000 μg/L), cadmium chloride (0.0002 and 0.002 μg/L), and atrazine (150 μg/L). In contrast, we observed a significant decrease in oxygen flux after exposures to potassium cyanide (5.2, 22, and 44 μg/L) and atrazine (1500 μg/L). No effects were detected after exposures to malathion (200 and 340 μg/L). We have also tested the sensitivity of Daphnia magna embryos as another animal model for real-time environmental biomonitoring. Our results are so far encouraging and support further development of this technology as a physiologically coupled biomonitoring tool for the detection of environmental toxicants.

  13. Neutron analysis of spent fuel storage installation using parallel computing and advance discrete ordinates and Monte Carlo techniques.

    Science.gov (United States)

    Shedlock, Daniel; Haghighat, Alireza

    2005-01-01

    In the United States, the Nuclear Waste Policy Act of 1982 mandated centralised storage of spent nuclear fuel by 1988. However, the Yucca Mountain project is currently scheduled to start accepting spent nuclear fuel in 2010. Since many nuclear power plants were only designed for -10 y of spent fuel pool storage, > 35 plants have been forced into alternate means of spent fuel storage. In order to continue operation and make room in spent fuel pools, nuclear generators are turning towards independent spent fuel storage installations (ISFSIs). Typical vertical concrete ISFSIs are -6.1 m high and 3.3 m in diameter. The inherently large system, and the presence of thick concrete shields result in difficulties for both Monte Carlo (MC) and discrete ordinates (SN) calculations. MC calculations require significant variance reduction and multiple runs to obtain a detailed dose distribution. SN models need a large number of spatial meshes to accurately model the geometry and high quadrature orders to reduce ray effects, therefore, requiring significant amounts of computer memory and time. The use of various differencing schemes is needed to account for radial heterogeneity in material cross sections and densities. Two P3, S12, discrete ordinate, PENTRAN (parallel environment neutral-particle TRANsport) models were analysed and different MC models compared. A multigroup MCNP model was developed for direct comparison to the SN models. The biased A3MCNP (automated adjoint accelerated MCNP) and unbiased (MCNP) continuous energy MC models were developed to assess the adequacy of the CASK multigroup (22 neutron, 18 gamma) cross sections. The PENTRAN SN results are in close agreement (5%) with the multigroup MC results; however, they differ by -20-30% from the continuous-energy MC predictions. This large difference can be attributed to the expected difference between multigroup and continuous energy cross sections, and the fact that the CASK library is based on the old ENDF

  14. Neutron tomography developments and applications

    OpenAIRE

    Richards, Wade J.; Gibbons, M. R.; Shields, K. C

    2003-01-01

    Neutron radiography has been in use as a nondestructive testing technique for the past fifty years. The neutrons’ unique ability to image certain elements and isotopes that are either completely undetectable or poorly detected by other NDI methods makes neutron radiography an important tool for the NDI community. Neutron radiography like other imaging techniques takes a number of different forms (i.e., film, radioscopic, transfer methods, tomography, etc.) This paper will describe ...

  15. Neutron beam applications

    International Nuclear Information System (INIS)

    For the materials science by neutron technique, the development of the various complementary neutron beam facilities at horizontal beam port of HANARO and the techniques for measurement and analysis has been performed. High resolution powder diffractometer, after the installation and performance test, has been opened and used actively for crystal structure analysis, magnetic structure analysis, phase transition study, etc., since January 1998. The main components for four circle diffractometer were developed and, after performance test, it has been opened for crystal structure analysis and texture measurement since the end of 1999. For the small angle neutron spectrometer, the main component development and test, beam characterization, and the preliminary experiment for the structure study of polymer have been carried out. Neutron radiography facility, after the precise performance test, has been used for the non-destructive test of industrial component. Addition to the development of main instruments, for the effective utilization of those facilities, the scattering techniques relating to quantitative phase analysis, magnetic structure analysis, texture measurement, residual stress measurement, polymer study, etc, were developed. For the neutron radiography, photographing and printing technique on direct and indirect method was stabilized and the development for the real time image processing technique by neutron TV was carried out. The sample environment facilities for low and high temperature, magnetic field were also developed

  16. CIUDENs Pilot Project for CO2 Biomonitoring Tools (PISCO2)

    Science.gov (United States)

    García, D.; Bruno, J.; Credoz, A.; Grandia, F.; Fuentes, J.; Calabuig, E.; Montoto, M.; Ciuden's Co2 Geological Storage Programme

    2011-12-01

    This paper describes CIUDENs Pilot Project for CO2 Biomonitoring Tools (PISCO2) in NW Spain; focusing on the development of biomonitoring of potential CO2 leakages through testing biogeochemical effects of CO2 injection in soils. CIUDEN is a Spanish National foundation created in 2006 dedicated to different projects related to energy and environment. One of the main activities is the construction and operation of various facilities for Research and Development in CCS. The PISCO2 installation consists of 18 cells excavated in the ground and isolated by concrete. Each cell has a 40 m3. The cells will be filled with different soils from various sites in Spain including the Hontomín site in Burgos, where CIUDENs CO2 Storage Technological Development Plant is under construction. The cells are be equipped with systems for (i) controlled CO2 injection at different depths, (ii) control of irrigation and drainage in the unsaturated soil, (iii) sampling of groundwater and gases, and (iv) monitoring of different parameters; such as water content, pH, CO2 flux, microbiological, botanical, and biogeochemical alterations and the chemical composition of water. The main objectives are: the detection of potential diffuse leakage during/after the injection operations; the use of native species as bio-indicators of early leakage; the calibration and optimization of monitoring sensors & methodologies; the optimization of existing multiphase reactive transport models and the comprehension improvement of the biogeochemical processes. The facility is planned to be fully operational in November 2011. Its configuration makes it unique and suitable for international R&D programs. CIUDEN is open for cooperative research projects with institutions all over the world. Results are expected to significantly contribute to the development of new, useful, economical and ecological biomonitoring tools for wide areas. The paper will focus on the presentation of the technical caracteristics and the

  17. Development of a 3He nuclear spin flip system on an in-situ SEOP 3He spin filter and demonstration for a neutron reflectometer and magnetic imaging technique

    Science.gov (United States)

    Hayashida, H.; Oku, T.; Kira, H.; Sakai, K.; Hiroi, K.; Ino, T.; Shinohara, T.; Imagawa, T.; Ohkawara, M.; Ohoyama, K.; Kakurai, K.; Takeda, M.; Yamazaki, D.; Oikawa, K.; Harada, M.; Miyata, N.; Akutsu, K.; Mizusawa, M.; Parker, J. D.; Matsumoto, Y.; Zhang, S.; Suzuki, J.; Soyama, K.; Aizawa, K.; Arai, M.

    2016-04-01

    We have been developing a 3He neutron spin filter (NSF) using the spin exchange optical pumping (SEOP) technique. The 3He NSF provides a high-energy polarized neutron beam with large beam size. Moreover the 3He NSF can work as a π-flipper for a polarized neutron beam by flipping the 3He nuclear spin using a nuclear magnetic resonance (NMR) technique. For NMR with the in-situ SEOP technique, the polarization of the laser must be reversed simultaneously because a non-reversed laser reduces the polarization of the spin-flipped 3He. To change the polarity of the laser, a half-wavelength plate was installed. The rotation angle of the half-wavelength plate was optimized, and a polarization of 97% was obtained for the circularly polarized laser. The 3He polarization reached 70% and was stable over one week. A demonstration of the 3He nuclear spin flip system was performed at the polarized neutron reflectometer SHARAKU (BL17) and NOBORU (BL10) at J-PARC. Off-specular measurement from a magnetic Fe/Cr thin film and magnetic imaging of a magnetic steel sheet were performed at BL17 and BL10, respectively.

  18. Neutron radiography using neutron imaging plate.

    Science.gov (United States)

    Chankow, Nares; Punnachaiya, Suvit; Wonglee, Sarinrat

    2010-01-01

    The aims of this research are to study properties of a neutron imaging plate (NIP) and to test it for use in nondestructive testing (NDT) of materials. The experiments were carried out by using a BAS-ND 2040 Fuji NIP and a neutron beam from the Thai Research Reactor TRR-1/M1. The neutron intensity and Cd ratio at the specimen position were approximately 9x10(5) ns/cm(2) s and 100 respectively. It was found that the photostimulated luminescence (PSL) readout of the imaging plate was directly proportional to the exposure time and approximately 40 times faster than the conventional NR using Gd converter screen/X-ray film technique. The sensitivities of the imaging plate to slow neutron and to Ir-192 gamma-rays were found to be approximately 4.2x10(-3) PSL/mm(2) per neutron and 6.7x10(-5) PSL/mm(2) per gamma-ray photon respectively. Finally, some specimens containing light elements were selected to be radiographed with neutrons using the NIP and the Gd converter screen/X-ray film technique. The image quality obtained from the two recording media was found to be comparable. PMID:19828321

  19. First steps toward harmonized human biomonitoring in Europe

    DEFF Research Database (Denmark)

    Den Hond, Elly; Govarts, Eva; Willems, Hanny;

    2015-01-01

    BACKGROUND: For Europe as a whole, data on internal exposure to environmental chemicals do not yet exist. Characterization of the internal individual chemical environment is expected to enhance understanding of the environmental threats to health. OBJECTIVES: We developed and applied a harmonized...... biomonitoring framework to support the decision-making process of environmental measures to protect public health.......-2012. We obtained information on personal characteristics, environment, and lifestyle. We used the resulting database to compare concentrations of exposure biomarkers within Europe, to identify determinants of exposure, and to compare exposure biomarkers with health-based guidelines. RESULTS: Biomarker...

  20. Conceptual framework for a Danish human biomonitoring program

    DEFF Research Database (Denmark)

    Thomsen, Marianne; Knudsen, Lisbeth E.; Vorkamp, Katrin;

    2008-01-01

    The aim of this paper is to present the conceptual framework for a Danish human biomonitoring (HBM) program. The EU and national science-policy interface, that is fundamental for a realization of the national and European environment and human health strategies, is discussed, including the need...... for a structured and integrated environmental and human health surveillance program at national level. In Denmark, the initiative to implement such activities has been taken. The proposed framework of the Danish monitoring program constitutes four scientific expert groups, i.e. i. Prioritization of the strategy...

  1. Neutron recognition in the LAND detector for large neutron multiplicity

    International Nuclear Information System (INIS)

    The performance of the LAND neutron detector is studied. Using an event-mixing technique based on one-neutron data obtained in the S107 experiment at the GSI laboratory, we test the efficiency of various analytic tools used to determine the multiplicity and kinematic properties of detected neutrons. A new algorithm developed recently for recognizing neutron showers from spectator decays in the ALADIN experiment S254 is described in detail. Its performance is assessed in comparison with other methods. The properties of the observed neutron events are used to estimate the detection efficiency of LAND in this experiment.

  2. Application des techniques de diffusion de la lumière des rayons X et des neutrons à l'étude des systèmes colloïdaux. Première partie : Présentation théorique des trois techniques Application of Light, X-Ray and Neutron Diffusion Techniques to the Study of Colloidal Systems. Part One : Theoretical Description of Three Techniques

    Directory of Open Access Journals (Sweden)

    Espinat D.

    2006-11-01

    Full Text Available Les techniques de diffusion, des rayons X, des neutrons et de la lumière, jouent un rôle très important pour la compréhension des milieux colloïdaux. Peu d'articles de la littérature s'attachent à présenter conjointement les trois méthodes. Nous avons, dans la première partie de cet article, détaillé les principes théoriques en insistent tout particulièrement sur les spécificités de chacune. Après les rappels concernant la diffusion par les systèmes dilués, nous nous sommes intéressés aux systèmes concentrés pour lesquels les entités diffusantes sont en interaction. Les milieux dispersés montrent souvent une certaine polydispersité que l'on cherche à mesurer; les techniques de diffusion permettent cette mesure. Nous terminerons cette revue par une description des appareillages utilisés. La deuxième partie de cet article concernera une large illustration des possibilités de ces méthodes d'analyse à l'étude des systèmes colloïdaux, sur la base de travaux effectués à I'IFP (Institut Français du Pétrole ou dans de nombreux laboratoires de recherche extérieurs. This article aims to describe X-ray, neutron and light scattering techniques with emphasis on their specific nature and their scope of application. Indeed, whereas light diffusion has been used for a long time in research laboratories, in particular for characterizing polymers in solution, small angle X-ray scattering has been the subject of renewed interest in recent years. Neutron scattering, which is obviously more difficultly accessible, has proven to be extremely useful for studying various systems for which light and X-ray scattering remain relatively powerless. Whereas there is an abundant literature concerning various applications of the three methods, it should be noted that only a few articles have attempted to describe all three techniques at the same time. In this article we have tried to make up for this lack, and as such it was

  3. THERMAL NEUTRON BACKSCATTER IMAGING.

    Energy Technology Data Exchange (ETDEWEB)

    VANIER,P.; FORMAN,L.; HUNTER,S.; HARRIS,E.; SMITH,G.

    2004-10-16

    Objects of various shapes, with some appreciable hydrogen content, were exposed to fast neutrons from a pulsed D-T generator, resulting in a partially-moderated spectrum of backscattered neutrons. The thermal component of the backscatter was used to form images of the objects by means of a coded aperture thermal neutron imaging system. Timing signals from the neutron generator were used to gate the detection system so as to record only events consistent with thermal neutrons traveling the distance between the target and the detector. It was shown that this time-of-flight method provided a significant improvement in image contrast compared to counting all events detected by the position-sensitive {sup 3}He proportional chamber used in the imager. The technique may have application in the detection and shape-determination of land mines, particularly non-metallic types.

  4. Neutrons against cancer

    Science.gov (United States)

    Dovbnya, A. N.; Kuplennikov, E. L.; Kandybey, S. S.; Krasiljnikov, V. V.

    2014-09-01

    The review is devoted to the analysis and generalization of the research carried out during recent years in industrially advanced countries on the use of fast, epithermal, and thermal neutrons for therapy of malignant tumors. Basic facilities for neutron production used for cancer treatment are presented. Optimal parameters of therapeutic beams are described. Techniques using neutrons of different energy regions are discussed. Results and medical treatment efficiency are given. Comparison of the current state of neutron therapy of tumors and alternative treatments with beams of protons and carbon ions has been conducted. Main attention is given to the possibility of the practical use of accumulated experience of application of neutron beams for cancer therapy.

  5. Fast neutrons dosimetry

    International Nuclear Information System (INIS)

    A proton recoil technique has been developed for inducing thermoluminescence with incident fast neutrons. CaF2 was used as the TL phosphor, and cane sugar and polyethylene were used as proton radiators. The phosphor and the hydrogeneous material powders were well mixed, encapsulated in glass tubes and exposed to Am-Be sources, resulting in recoils from incident fast neutrons of energy between 0,25 and 11,25 MeV. The intrinsic response of pure CaF2 to fast neutrons without a hydrogeneous radiator was checked by using LiF (TLD-700). Glow curves were recorded from room temperature up to 3500C after different doses of neutrons and gamma rays of 60Co. First collision dose due to fast neutrons in tissue like materials such as cane sugar and polyethylene was also calculated

  6. Neutron beam applications - Development of operational techniques for neutron four-circle diffractometer and structure determination of C{sub 16}H{sub 15}NO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Moon Jib [Soonchunhyang University, Asan (Korea); Suh, Il Hwan [Chungnam National University, Taejon (Korea)

    1999-06-01

    We have been studied to find out the experimental methods and procedures for neutron diffraction method for neutron diffractometer in HANARO -the atomic research reactor in KAERI. We have studied experimental process for the neutron diffraction data analysis, using computer soft-wares such as SHELXS for the calculation the initial phase of crystal structure, SHELXL for refinement of atomic coordinate using least-squares method, ORTEP for the display of the calculated positions of molecule, and PATSEE for the calculation of the phase from the expected structure. In these studies, we analyzed the structure of test sample using these programs, and prepare the user's manual for these soft-wares. We have also studied on bending effect of monochromator in order to increase the intensity of neutron beam, and designed HRPD - High Resolution Powder Diffractometers. 7 refs., 6 figs. (Author)

  7. Characterization of ancient glass excavated in Enez (Ancient Ainos) Turkey by combined Instrumental Neutron Activation Analysis and Fourier Transform Infrared spectrometry techniques

    Energy Technology Data Exchange (ETDEWEB)

    Akyuz, Sevim, E-mail: s.akyuz@iku.edu.tr [Physics Department, Science and Letters Faculty, Istanbul Kultur University, Atakoy Campus, Bakirkoy 34156, Istanbul (Turkey); Akyuz, Tanil [Physics Department, Science and Letters Faculty, Istanbul Kultur University, Atakoy Campus, Bakirkoy 34156, Istanbul (Turkey); Mukhamedshina, Nuranya M.; Mirsagatova, A. Adiba [Institute of Nuclear Physics, Uzbek Academy of Sciences, 702132, Ulugbek, Tashkent (Uzbekistan); Basaran, Sait; Cakan, Banu [Department of Restoration and Conservation of Artefacts, Letters Faculty, Istanbul University, Vezneciler, Istanbul (Turkey)

    2012-05-15

    Ancient glass fragments excavated in the archaeological district Enez (Ancient Ainos)-Turkey were investigated by combined Instrumental Neutron Activation Analysis (INAA) and Fourier Transform Infrared (FTIR) spectrometry techniques. Multi-elemental contents of 15 glass fragments that belong to Hellenistic, Roman, Byzantine, and Ottoman Periods, were determined by INAA. The concentrations of twenty six elements (Na, K, Ca, Sc, Cr, Mn, Fe, Co, Cu, Zn, As, Rb, Sr, Sb, Cs, Ba, Ce, Sm, Eu, Tb, Yb, Lu, Hf, Ta, Au and Th), which might be present in the samples as flux, stabilizers, colorants or opacifiers, and impurities, were examined. Chemometric treatment of the INAA data was performed and principle component analysis revealed presence of 3 distinct groups. The thermal history of the glass samples was determined by FTIR spectrometry. - Highlights: Black-Right-Pointing-Pointer INAA was performed to determine elemental compositions of ancient glass fragments. Black-Right-Pointing-Pointer Basic, coloring/discoloring elements and impurities have been determined. Black-Right-Pointing-Pointer PCA discriminated the glasses depending on their chronological order. Black-Right-Pointing-Pointer The thermal history of the glass samples was determined by FTIR spectrometry.

  8. Atomic-absorption spectrometric, neutron-activation and radioanalytical techniques for the determination of trace metals in environmental, biochemical and toxicological research

    International Nuclear Information System (INIS)

    Radioanalytical techniques and atomic-absorption spectrometry have been used for the micro-determination of vanadium in biological specimens such as human tissues and body fluids in environmental, biochemical and toxicological research. The use of 48V as a radiotracer permitted investigations on the vaporisation and retention mechanisms of vanadium. Higher vanadium oxides are probably converted into lower oxides, decomposing to VO in gaseous form, followed by the dissociation to 'free vanadium' and oxygen. It was found that about 20% of the 48V radioactivity was consistently retained in the graphite tube after 10 repeated introductions and firings of 50 μl of 50 ng ml-148V-labelled vanadium solution. However, the amount retained, probably in the form of carbide, does not vaporise under the conditions used for the analysis. Determinations of vanadium at the parts per billion level in 10 urine samples by neutron-activation analysis and by graphite furnace atomic-absorption spectrometry showed agreement that can be considered satisfactory for practical purposes. (author)

  9. In Situ Characterization Techniques Based on Synchrotron Radiation and Neutrons Applied for the Development of an Engineering Intermetallic Titanium Aluminide Alloy

    Directory of Open Access Journals (Sweden)

    Petra Erdely

    2016-01-01

    Full Text Available Challenging issues concerning energy efficiency and environmental politics require novel approaches to materials design. A recent example with regard to structural materials is the emergence of lightweight intermetallic TiAl alloys. Their excellent high-temperature mechanical properties, low density and high stiffness constitute a profile perfectly suitable for their application as advanced aero-engine turbine blades or as turbocharger turbine wheels in next-generation automotive engines. As the properties of TiAl alloys during processing as well as during service are dependent on the phases occurring, detailed knowledge of their volume fractions and distribution within the microstructure is of paramount importance. Furthermore, the behavior of the individual phases during hot deformation and subsequent heat treatments is of interest to define reliable and cost-effective industrial production processes. In situ high-energy X-ray diffraction methods allow tracing the evolution of phase fractions over a large temperature range. Neutron diffraction unveils information on order-disorder transformations in TiAl alloys. Small-angle scattering experiments offer insights into the materials’ precipitation behavior. This review attempts to shine a light on selected in situ diffraction and scattering techniques and the ways in which they promoted the development of an advanced engineering TiAl alloy.

  10. Characterization of ancient glass excavated in Enez (Ancient Ainos) Turkey by combined Instrumental Neutron Activation Analysis and Fourier Transform Infrared spectrometry techniques

    International Nuclear Information System (INIS)

    Ancient glass fragments excavated in the archaeological district Enez (Ancient Ainos)–Turkey were investigated by combined Instrumental Neutron Activation Analysis (INAA) and Fourier Transform Infrared (FTIR) spectrometry techniques. Multi-elemental contents of 15 glass fragments that belong to Hellenistic, Roman, Byzantine, and Ottoman Periods, were determined by INAA. The concentrations of twenty six elements (Na, K, Ca, Sc, Cr, Mn, Fe, Co, Cu, Zn, As, Rb, Sr, Sb, Cs, Ba, Ce, Sm, Eu, Tb, Yb, Lu, Hf, Ta, Au and Th), which might be present in the samples as flux, stabilizers, colorants or opacifiers, and impurities, were examined. Chemometric treatment of the INAA data was performed and principle component analysis revealed presence of 3 distinct groups. The thermal history of the glass samples was determined by FTIR spectrometry. - Highlights: ► INAA was performed to determine elemental compositions of ancient glass fragments. ► Basic, coloring/discoloring elements and impurities have been determined. ► PCA discriminated the glasses depending on their chronological order. ► The thermal history of the glass samples was determined by FTIR spectrometry.

  11. Feasibility study for measurement of insulation compaction in the cryogenic rocket fuel storage tanks at Kennedy Space Center by fast/thermal neutron techniques

    Energy Technology Data Exchange (ETDEWEB)

    Livingston, R. A. [Materials Science and Engineering Dept., U. of Maryland, College Park, MD (United States); Schweitzer, J. S. [Physics Dept., U. of Connecticut, Storrs (United States); Parsons, A. M. [Goddard Space Flight Center, Greenbelt (United States); Arens, E. E. [John F. Kennedy Space Center, FL (United States)

    2014-02-18

    The liquid hydrogen and oxygen cryogenic storage tanks at John F. Kennedy Space Center (KSC) use expanded perlite as thermal insulation. Some of the perlite may have compacted over time, compromising the thermal performance and also the structural integrity of the tanks. Neutrons can readily penetrate through the 1.75 cm outer steel shell and through the entire 120 cm thick perlite zone. Neutrons interactions with materials produce characteristic gamma rays which are then detected. In compacted perlite the count rates in the individual peaks in the gamma ray spectrum will increase. Portable neutron generators can produce neutron simultaneous fluxes in two energy ranges: fast (14 MeV) and thermal (25 meV). Fast neutrons produce gamma rays by inelastic scattering which is sensitive to Si, Al, Fe and O. Thermal neutrons produce gamma rays by radiative capture in prompt gamma neutron activation (PGNA), which is sensitive to Si, Al, Na, K and H among others. The results of computer simulations using the software MCNP and measurements on a test article suggest that the most promising approach would be to operate the system in time-of-flight mode by pulsing the neutron generator and observing the subsequent die away curve in the PGNA signal.

  12. Feasibility study for measurement of insulation compaction in the cryogenic rocket fuel storage tanks at Kennedy Space Center by fast/thermal neutron techniques

    International Nuclear Information System (INIS)

    The liquid hydrogen and oxygen cryogenic storage tanks at John F. Kennedy Space Center (KSC) use expanded perlite as thermal insulation. Some of the perlite may have compacted over time, compromising the thermal performance and also the structural integrity of the tanks. Neutrons can readily penetrate through the 1.75 cm outer steel shell and through the entire 120 cm thick perlite zone. Neutrons interactions with materials produce characteristic gamma rays which are then detected. In compacted perlite the count rates in the individual peaks in the gamma ray spectrum will increase. Portable neutron generators can produce neutron simultaneous fluxes in two energy ranges: fast (14 MeV) and thermal (25 meV). Fast neutrons produce gamma rays by inelastic scattering which is sensitive to Si, Al, Fe and O. Thermal neutrons produce gamma rays by radiative capture in prompt gamma neutron activation (PGNA), which is sensitive to Si, Al, Na, K and H among others. The results of computer simulations using the software MCNP and measurements on a test article suggest that the most promising approach would be to operate the system in time-of-flight mode by pulsing the neutron generator and observing the subsequent die away curve in the PGNA signal

  13. Nobel Prize in Physics 1994 "for pioneering contributions to the development of neutron scattering techniques for studies of condensed matter" : Bertram N. Brockhouse and Clifford G. Shull

    CERN Document Server

    1995-01-01

    Prof. C. G. Shull presents "Early development of neutron scattering". A description of the early experiments and instrumentation problems starting in 1946 that led to the use of neutron scattering as a tool in augmenting and extending x-ray scattering from materials.

  14. Detectors for Energy-Resolved Fast Neutron Imaging

    OpenAIRE

    Dangendorf, V.; Breskin, A.; Chechik, R.; Feldman, G.; Goldberg, M B; Jagutzki, O.; Kersten, C.; Laczko, G; Mor, I.; Spillman, U.; Vartsky, D.

    2004-01-01

    Two detectors for energy-resolved fast-neutron imaging in pulsed broad-energy neutron beams are presented. The first one is a neutron-counting detector based on a solid neutron converter coupled to a gaseous electron multiplier (GEM). The second is an integrating imaging technique, based on a scintillator for neutron conversion and an optical imaging system with fast framing capability.

  15. The use of unstable chromosome aberrations and micronuclei in the individual biomonitoring: a comparative study

    International Nuclear Information System (INIS)

    Biodosimetry is based on the investigation of radioinduced biological effects in order to correlate them with the absorbed dose. The quantification of unstable chromosome aberrations and micronuclei, in peripheral blood lymphocytes, are two methods commonly used in biodosimetry. In this context, the aim of this research was to compare these methods in the biomonitoring of health care professionals occupationally exposed to ionizing radiation. In parallel, the technique of C-banding was evaluated for quality control of unstable chromosome aberrations analyses. Thus, samples of peripheral blood from health care professionals of three hospitals from Recife (Brazil) were collected, and the lymphocytes cultures were carried out based on the cytogenetic classical technique. It was pointed out that analysis of micronuclei is faster than the unstable chromosome aberrations ones, which suggests the use of the former in preliminary evaluation in cases of suspected accidental exposure. C-banding technique was efficient, as confirmatory test, in the identification of dicentrics and rings during the analyses of unstable chromosome aberrations, being able to be applied in the quality control in biodosimetry. The comparison between the individual work conditions with the frequencies of unstable aberrations and micronuclei obtained from cytogenetic analysis, resulted in the change of behavior of the professionals involved in this research, with a better observance of the radioprotection standards. (author)

  16. Using the pollen viability and morphology for fluoride pollution biomonitoring.

    Science.gov (United States)

    Malayeri, Behrooz Eshghi; Noori, Mitra; Jafari, Mehrana

    2012-06-01

    The methods using plants for biomonitoring of air and soil quality are simple, cheap, and fast and can supplement the classical physicochemical methods. In this study, biological pollen characterization of some collected legume species from an aluminum smelter area in Iran (IRALCO) was carried out to determine the actual value of pollen as a bioindicator of the effects of soil and atmospheric pollution. Young buds and flowers of six legumes (Cercis siliquastrum L., Medicago sativa L., Robinia pseudoacacia L., Melilotus officinalis (L.) lam, Trifolium repens L., and Sophora alopecuroides L.) in polluted and control plants were removed and compared. Studies of light and electron microscopic preparation showed some abnormalities during pollen development in affect of fluoride pollution. The viability of pollen grains estimated by staining with acetocarmine shows sharp differences in smearing advanced pollen grains from abnormal ones. Except M. officinalis, the pollen grains of C. siliquastrum, M. sativa, R. pseudoacacia, T. repens, and S. alopecuroides in polluted areas showed light, partial, or no staining with acetocarmine, whereas almost all of the control ones clearly stained. Observation of the pollen grains by light microscopy and scanning electron microscopy showed the significant effect of fluoride on shapes and sizes of pollen grains. The stimulation and inhibition of these pollen characteristics depend on the pollen species as well as on the pollutant and its concentration. Therefore, pollen grains provide essential information on biological impact of pollutants and they are good candidates for biomonitoring the atmospheric and edaphic pollutions. PMID:22161315

  17. Phtalates in Lithuanian environment and needs for human biomonitoring

    Directory of Open Access Journals (Sweden)

    Gediminas Balčius

    2012-06-01

    Full Text Available Controlling chemical substances and correct evaluation of danger and risk caused by them, based on scientific research are necessary in order to keep environment and public health safe. Regulation signed by European Parliament and Council to control registration, evaluation, authorization and limitation of chemical substances (REACH is the main juridical act from the new European Union‘s policy regarding regulation of chemical substances. Objective of this research was to gather and analyze data regarding phthalates used in Lithuania‘s industry, to present data on its environmental levels in surface water, sediments, sewage treatment plant effluents, and to discuss the needs for the human biomonitoring in Lithuania. The amount of diethylhexyl phthalate yielded to Lithuania‘s industry and market, incresed 65 times from 3,7t in 2003 to 240,81t in 2007. DEHP concentrations in Lithuania in wastewater exceeded regulated annual average maximum allowable concentrations up to 27 times and maximum allowable concentrations up to 13 times. High environmental concentrations of phthalates pointed out to the needs of establishment of permanent human biomonitoring in Lithuania.DOI: http://dx.doi.org/10.5755/j01.erem.60.2.863

  18. Assessing exposure to phthalates - the human biomonitoring approach.

    Science.gov (United States)

    Wittassek, Matthias; Koch, Holger Martin; Angerer, Jürgen; Brüning, Thomas

    2011-01-01

    Some phthalates are developmental and reproductive toxicants in animals. Exposure to phthalates is considered to be potentially harmful to human health as well. Based on a comprehensive literature research, we present an overview of the sources of human phthalate exposure and results of exposure assessments with special focus on human biomonitoring data. Among the general population, there is widespread exposure to a number of phthalates. Foodstuff is the major source of phthalate exposure, particularly for the long-chain phthalates such as di(2-ethylhexyl) phthalate. For short-chain phthalates such as di-n-butyl-phthalate, additional pathways are of relevance. In general, children are exposed to higher phthalate doses than adults. Especially, high exposures can occur through some medications or medical devices. By comparing exposure data with existing limit values, one can also assess the risks associated with exposure to phthalates. Within the general population, some individuals exceed tolerable daily intake values for one or more phthalates. In high exposure groups, (intensive medical care, medications) tolerable daily intake transgressions can be substantial. Recent findings from animal studies suggest that a cumulative risk assessment for phthalates is warranted, and a cumulative exposure assessment to phthalates via human biomonitoring is a major step into this direction.

  19. Using the pollen viability and morphology for fluoride pollution biomonitoring.

    Science.gov (United States)

    Malayeri, Behrooz Eshghi; Noori, Mitra; Jafari, Mehrana

    2012-06-01

    The methods using plants for biomonitoring of air and soil quality are simple, cheap, and fast and can supplement the classical physicochemical methods. In this study, biological pollen characterization of some collected legume species from an aluminum smelter area in Iran (IRALCO) was carried out to determine the actual value of pollen as a bioindicator of the effects of soil and atmospheric pollution. Young buds and flowers of six legumes (Cercis siliquastrum L., Medicago sativa L., Robinia pseudoacacia L., Melilotus officinalis (L.) lam, Trifolium repens L., and Sophora alopecuroides L.) in polluted and control plants were removed and compared. Studies of light and electron microscopic preparation showed some abnormalities during pollen development in affect of fluoride pollution. The viability of pollen grains estimated by staining with acetocarmine shows sharp differences in smearing advanced pollen grains from abnormal ones. Except M. officinalis, the pollen grains of C. siliquastrum, M. sativa, R. pseudoacacia, T. repens, and S. alopecuroides in polluted areas showed light, partial, or no staining with acetocarmine, whereas almost all of the control ones clearly stained. Observation of the pollen grains by light microscopy and scanning electron microscopy showed the significant effect of fluoride on shapes and sizes of pollen grains. The stimulation and inhibition of these pollen characteristics depend on the pollen species as well as on the pollutant and its concentration. Therefore, pollen grains provide essential information on biological impact of pollutants and they are good candidates for biomonitoring the atmospheric and edaphic pollutions.

  20. Active biomonitoring of heavy metal pollution using Rosa rugosa plants

    Energy Technology Data Exchange (ETDEWEB)

    Calzoni, Gian Lorenzo [Dip. Biologia, Universita di Bologna, via Irnerio 42, 40126 Bologna (Italy)], E-mail: gianlorenzo.calzoni@unibo.it; Antognoni, Fabiana [Dip. Biologia, Universita di Bologna, via Irnerio 42, 40126 Bologna (Italy)], E-mail: fabiana.antognoni@unibo.it; Pari, Elena [Gruppo CSA-SpA, via al Torrente 22, Rimini (Italy)], E-mail: epari@csaricerche.com; Fonti, Paolo [Gruppo CSA-SpA, via al Torrente 22, Rimini (Italy)], E-mail: pfonti@csaricerche.com; Gnes, Antonio [ARPA - Agenzia Regionale Protezione Ambientale, Sez. Provinciale di Ravenna, via Alberoni 17, Ravenna (Italy)], E-mail: agnes@ra.arpa.emr.it; Speranza, Anna [Dip. Biologia, Universita di Bologna, via Irnerio 42, 40126 Bologna (Italy)], E-mail: anna.speranza@unibo.it

    2007-09-15

    The purpose of this work was to evaluate the quality of a rural area near Faenza (Italy) by using an active biomonitoring approach, i.e., by placing homogeneous individuals of the perennial shrub Rosa rugosa in different sites throughout the area. Further sites, within the city or its environs, were used for comparison. Soil and leaves of R. rugosa were analyzed for their heavy metal content. The total heavy metal pattern of leaves closely paralleled the pattern registered in soil, with the highest content (both in total and assimilable forms) at the site in the urban area, which is exposed to heavy traffic. Pollen quality (abortiveness and viability) was also tested as a potential indicator of pollution. Pollen abortiveness was strictly related to Pb levels in leaves, while viability was inversely related to leaf Cr content. Our results suggest that R. rugosa has the potential to be a good biomonitoring system. - Rosa rugosa leaves and pollen are - to different extents - suitable monitoring tools for heavy metal pollution.

  1. Analysis of neutron flux distribution using the Monte Carlo method for the feasibility study of the Prompt Gamma Activation Analysis technique at the IPR-R1 TRIGA reactor

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, Bruno T.; Pereira, Claubia, E-mail: brunoteixeiraguerra@yahoo.com.br, E-mail: claubia@nuclear.ufmg.br [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte, MG (Brazil). Departmento de Energia Nuclear; Soares, Alexandre L.; Menezes, Maria Angela B.C., E-mail: menezes@cdtn.br, E-mail: asleal@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2015-07-01

    The IPR-R1 is a reactor type TRIGA, Mark-I model, manufactured by the General Atomic Company and installed at Nuclear Technology Development Centre (CDTN), Brazilian Commission for Nuclear Energy (CNEN), in Belo Horizonte, Brazil. It is a light water moderated and cooled, graphite-reflected, open-pool type research reactor and operates at 100 kW. It presents low power, low pressure, for application in research, training and radioisotopes production. The fuel is an alloy of zirconium hydride and uranium enriched at 20% in {sup 235}U. The implementation of the PGNAA (Prompt Gamma Neutron Activation Analysis) using this research reactor will significantly increase in number of chemical elements analysed and the kind of matrices. A project is underway in order to implement this technique at CDTN. The objective of this study was to contribute in feasibility analysis of implementing this technique. For this purpose, MCNP is being used. Some variance reduction tools in the methodology, that has been already developed, was introduced for calculating of the neutron flux in the neutron extractor inclined. The objective was to reduce the code error and thereby increasing the reliability of the results. With the implementation of the variance reduction tools, the results of the thermal and epithermal neutron fluxes presented a significant improvement in both calculations. (author)

  2. Characterization of the CO2 fluid adsorption in coal as a function of pressure using neutron scattering techniques (SANS and USANS)

    Science.gov (United States)

    Melnichenko, Y.B.; Radlinski, A.P.; Mastalerz, Maria; Cheng, G.; Rupp, J.

    2009-01-01

    Small angle neutron scattering techniques have been applied to investigate the phase behavior of CO2 injected into coal and possible changes in the coal pore structure that may result from this injection. Three coals were selected for this study: the Seelyville coal from the Illinois Basin (Ro = 0.53%), Baralaba coal from the Bowen Basin (Ro = 0.67%), and Bulli 4 coal from the Sydney Basin (Ro = 1.42%). The coals were selected from different depths to represent the range of the underground CO2 conditions (from subcritical to supercritical) which may be realized in the deep subsurface environment. The experiments were conducted in a high pressure cell and CO2 was injected under a range of pressure conditions, including those corresponding to in-situ hydrostatic subsurface conditions for each coal. Our experiments indicate that the porous matrix of all coals remains essentially unchanged after exposure to CO2 at pressures up to 200??bar (1??bar = 105??Pa). Each coal responds differently to the CO2 exposure and this response appears to be different in pores of various sizes within the same coal. For the Seelyville coal at reservoir conditions (16????C, 50??bar), CO2 condenses from a gas into liquid, which leads to increased average fluid density in the pores (??pore) with sizes (r) 1 ?? 105 ??? r ??? 1 ?? 104???? (??pore ??? 0.489??g/cm3) as well as in small pores with size between 30 and 300???? (??pore ??? 0.671??g/cm3). These values are by a factor of three to four higher than the density of bulk CO2 (??CO2) under similar thermodynamic conditions (??CO2 ??? 0.15??g/cm3). At the same time, in the intermediate size pores with r ??? 1000???? the average fluid density is similar to the density of bulk fluid, which indicates that adsorption does not occur in these pores. At in situ conditions for the Baralaba coal (35 OC, 100??bar), the average fluid density of CO2 in all pores is lower than that of the bulk fluid (??pore / ??CO2 ??? 0.6). Neutron scattering from the

  3. PGNAA 方法学的发展与现状%Development and Status of Prompt Gamma Neutron Activation Analysis Technique Methodology

    Institute of Scientific and Technical Information of China (English)

    王兴华; 孙洪超; 姚永刚; 肖才锦; 张贵英; 金象春; 华龙; 周四春

    2014-01-01

    Prompt Gamma Neutron Activation Analysis (PGNAA) is one of the nonde‐structive and On‐line measurement of nuclear analytical methods ,There are more than 30 PGNAA laboratories which are established based on the research reactor currently . The basic principle and the application field of three kinds of analytical method of PGNAA were introduced ,such as the relative comparison method、calibration method、k0‐factor method .T he short life nuclides is proposed using the beam chopper technique in order to improve the measurement accuracy . T he internal standard method w as proposed for that large sample neutron measurement that brings self absorption and gamma‐ray self shielding effect .The PGNAA system was introduced at CARR .It pro‐vides methodology reference to establish the prompt gamma activation analysis on the base of CARR for our country .%瞬发伽马中子活化分析(PGNAA)为非破坏性、在线测量的核分析方法。目前国际上有30多座研究堆建立了PGNAA实验室。本文介绍了三种定量瞬发伽马活化分析方法:相对法、校准曲线法、k0因子法,阐述了基本原理及其应用领域,以及针对短寿命核素高精度测量的束流斩波器技术,针对大样品测量带来的中子自吸收和伽马自屏蔽效应的内标法。此外还简介了基于CARR堆的热中子瞬发伽马活化分析装置进展情况,对国内的PGNAA问题进行了探讨。

  4. Neutron phase spin echo

    CERN Document Server

    Piegsa, Florian M; Schanzer, Christian

    2016-01-01

    A novel neutron spin resonance technique is presented based on the well-know neutron spin echo method. In a first proof-of-principle measurement using a monochromatic neutron beam, it is demonstrated that relative velocity changes of down to a precision of $4 \\times 10^{-7}$ can be resolved, corresponding to an energy resolution of better than 3~neV. Currently, the sensitivity is only limited by counting statistics and not by systematic effects. An improvement by another two orders of magnitude can be achieved with a dedicated setup, allowing for energy resolutions in the 10~peV regime. The new technique is ideally suited for investigations in the field of precision fundamental neutron physics, but will also be beneficial in scattering applications.

  5. Neutron signal transfer analysis

    CERN Document Server

    Pleinert, H; Lehmann, E

    1999-01-01

    A new method called neutron signal transfer analysis has been developed for quantitative determination of hydrogenous distributions from neutron radiographic measurements. The technique is based on a model which describes the detector signal obtained in the measurement as a result of the action of three different mechanisms expressed by signal transfer functions. The explicit forms of the signal transfer functions are determined by Monte Carlo computer simulations and contain only the distribution as a variable. Therefore an unknown distribution can be determined from the detector signal by recursive iteration. This technique provides a simple and efficient tool for analysis of this type while also taking into account complex effects due to the energy dependency of neutron interaction and single and multiple scattering. Therefore this method provides an efficient tool for precise quantitative analysis using neutron radiography, as for example quantitative determination of moisture distributions in porous buil...

  6. Neutron Skins and Neutron Stars

    OpenAIRE

    Piekarewicz, J

    2013-01-01

    The neutron-skin thickness of heavy nuclei provides a fundamental link to the equation of state of neutron-rich matter, and hence to the properties of neutron stars. The Lead Radius Experiment ("PREX") at Jefferson Laboratory has recently provided the first model-independence evidence on the existence of a neutron-rich skin in 208Pb. In this contribution we examine how the increased accuracy in the determination of neutron skins expected from the commissioning of intense polarized electron be...

  7. A new way to contemplate Darwin's tangled bank: how DNA barcodes are reconnecting biodiversity science and biomonitoring.

    Science.gov (United States)

    Hajibabaei, Mehrdad; Baird, Donald J; Fahner, Nicole A; Beiko, Robert; Golding, G Brian

    2016-09-01

    Encompassing the breadth of biodiversity in biomonitoring programmes has been frustrated by an inability to simultaneously identify large numbers of species accurately and in a timely fashion. Biomonitoring infers the state of an ecosystem from samples collected and identified using the best available taxonomic knowledge. The advent of DNA barcoding has now given way to the extraction of bulk DNA from mixed samples of organisms in environmental samples through the development of high-throughput sequencing (HTS). This DNA metabarcoding approach allows an unprecedented view of the true breadth and depth of biodiversity, but its adoption poses two important challenges. First, bioinformatics techniques must simultaneously perform complex analyses of large datasets and translate the results of these analyses to a range of users. Second, the insights gained from HTS need to be amalgamated with concepts such as Linnaean taxonomy and indicator species, which are less comprehensive but more intuitive. It is clear that we are moving beyond proof-of-concept studies to address the challenge of implementation of this new approach for environmental monitoring and regulation. Interpreting Darwin's 'tangled bank' through a DNA lens is now a reality, but the question remains: how can this information be generated and used reliably, and how does it relate to accepted norms in ecosystem study?This article is part of the themed issue 'From DNA barcodes to biomes'. PMID:27481782

  8. A new way to contemplate Darwin's tangled bank: how DNA barcodes are reconnecting biodiversity science and biomonitoring

    Science.gov (United States)

    Baird, Donald J.; Fahner, Nicole A.; Beiko, Robert; Golding, G. Brian

    2016-01-01

    Encompassing the breadth of biodiversity in biomonitoring programmes has been frustrated by an inability to simultaneously identify large numbers of species accurately and in a timely fashion. Biomonitoring infers the state of an ecosystem from samples collected and identified using the best available taxonomic knowledge. The advent of DNA barcoding has now given way to the extraction of bulk DNA from mixed samples of organisms in environmental samples through the development of high-throughput sequencing (HTS). This DNA metabarcoding approach allows an unprecedented view of the true breadth and depth of biodiversity, but its adoption poses two important challenges. First, bioinformatics techniques must simultaneously perform complex analyses of large datasets and translate the results of these analyses to a range of users. Second, the insights gained from HTS need to be amalgamated with concepts such as Linnaean taxonomy and indicator species, which are less comprehensive but more intuitive. It is clear that we are moving beyond proof-of-concept studies to address the challenge of implementation of this new approach for environmental monitoring and regulation. Interpreting Darwin's ‘tangled bank’ through a DNA lens is now a reality, but the question remains: how can this information be generated and used reliably, and how does it relate to accepted norms in ecosystem study? This article is part of the themed issue ‘From DNA barcodes to biomes’. PMID:27481782

  9. Neutron Compton Scattering

    OpenAIRE

    Watson, Greg

    1996-01-01

    Neutron Compton scattering measurements have the potential to provide direct information about atomic momentum distributions and adiabatic energy surfaces in condensed matter. First applied to measuring the condensate fraction in superfluid helium, the technique has recently been extended to study a variety of classical and quantum liquids and solids. This article reviews the theoretical background for the interpretation of neutron Compton scattering, with emphasis on studies of solids.

  10. Passive neutron assay of irradiated nuclear fuels

    International Nuclear Information System (INIS)

    Passive neutron assay of irradiated nuclear fuel has been investigated by calculations and experiments as a simple, complementary technique to the gamma assay. From the calculations it is found that the neutron emission arises mainly from the curium isotopes, the neutrons exhibit very good penetrability of the assemblies, and the neutron multiplication is not affected by the burnup. From the experiments on BWR and PWR assemblies, it is found that the neutron emission rate is proportional to burnup raised to 3.4 power. Recent investigations indicate that the passive neutron assay is a simple and useful technique to determine the consistency of burnups between assemblies. 10 refs

  11. Passive neutron assay of irradiated nuclear fuels

    International Nuclear Information System (INIS)

    Passive neutron assay of irradiated nuclear fuel has been investigated by calculations and experiments as a simple, complementary technique to the gamma assay. From the calculations it was found that the neutron emission arises mainly from the curium isotopes, the neutrons exhibit very good penetrability of the assemblies, and the neutron multiplication is not affected by the burnup. From the experiments on BWR and PWR assemblies, the neutron emission rate is proportional to burnup raised to 3.4 power. The investigations indicate that the passive neutron assay is a simple and useful technique to determine the consistency of burnups between assemblies

  12. Neutron reflectometry: Filling Δq with neutrons

    Science.gov (United States)

    Pleshanov, N. K.

    2016-06-01

    Luminosity of the reflectometer is defined as the neutron flux incident onto the sample surface for measurements made with a given momentum transfer resolution Δq. The filling of Δq with neutrons near a certain q depends not only on the source luminance and the source-sample tract transmittance, but also on the neutron beam tailoring. The correct choice of the working wavelength and measurements with optimum neutron beam parameters increase luminosity in several times. New optimization criteria for neutron reflectometers are suggested. Standard schemes of the reflectivity measurement with monochromatic and white beams are re-examined. Optimization of reflectivity measurements generally requires numerical calculations. Analytically, its potential is demonstrated by considering thermalized neutron beams. Such innovations as velocity selector on the basis of aperiodic multilayers, small angle Soller collimator with traps for neutrons reflected from the channel walls and fan beam time-of-flight technique are proposed to further increase the luminosity of reflectometers.

  13. Attitude-adjusting table for neutron monochromator

    International Nuclear Information System (INIS)

    The neutron monochromator attitude-adjusting table is one of the mechanical components for most monochromatic neutron scattering spectrometer. It is mainly used for mounting crystal monochromator, and getting monochromatic neutron by adjusting the attitude of monochromator remotely. The table has a compact volume and five adjusting axes with high resolution. It combines optic mechanical electronic technique with computer control technique. This device will be applied to the neutron residual stress spectrometer on CARR firstly. (authors)

  14. Neutrons for materials science

    International Nuclear Information System (INIS)

    The discussion will be limited to applied materials research performed on a customer/contractor basis. The information obtained using neutrons must therefore compete both scientifically and financially with information obtained using other techniques, particularly electron microscopy, X-ray, NMR, infra-red and Raman spectroscopy. It will be argued that the unique nature of the information gained from neutrons often outweighs the undoubted difficulties of access to neutron beams. Examples are given. Small angle scattering has emerged as the neutron technique of widest application in applied materials research. The penetration of neutron beams through containment vessels, as well as through the sample, allows the measurement of 'in situ' time dependent experiments within a furnace, cryostat, pressure vessel or chemical reactor vessel. High resolution powder diffraction is another technique with wide applications. Structural studies are possible on increasing complex phases. The structure and volume fraction of minority phases can be measured at levels appreciably below that possible by X-ray diffraction. A rapidly growing field at present is the measurement of internal strains through the small shifts in lattice spacing. Inelastic scattering measurements exploit the unique property of neutrons to measure the orientations of vibrating molecules. (author)

  15. Preliminary Study on Neutron Radiography with Several Hundred keV Fast Neutrons

    International Nuclear Information System (INIS)

    Several hundred keV fast neutron radiography (HKFNR) can be a complementary technique to common thermal neutron radiography (TNR) and several MeV fast neutron radiography (MFNR). We tested HKFNR on a 4.5 MV Van de Graaff accelerator, and the experimental results show that the spatial resolution of this technique is better than MFNR and close to TNR. Several hundred keV fast neutrons can penetrate some thermal neutron absorbers such as Cd, and it is feasible to investigate its use on some materials which are transparent to cold/thermal neutrons, such as aluminum, using this technique

  16. Thermal Neutron Computed Tomography of Soil Water and Plant Roots

    OpenAIRE

    Leanne G. Tumlinson; Hungyuan Liu; Wendy K. Silk; Hopmans, Jan W.

    2007-01-01

    Neutron radiography is a noninvasive imaging technique that measures the attenuation of thermal neutrons, as is done with x-ray and γ-ray radiography, to characterize the internal composition of materials. Neutron and x-ray imaging are complementary techniques, with neutron imaging especially well suited for materials containing H atoms and other low-atomic-weight attenuating materials. Although neutron computed tomography (NCT) techniques are routinely used in engineering, relatively little ...

  17. 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......Humans are widely exposed to chemicals. Today, there is an increased acknowledgement of the importance of measuring human and environmental exposures to man-made or refined chemicals. Different approaches have been applied over time, but during the past 25 years, there has been a general trend...... 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...

  18. A pilot study on the feasibility of European harmonized Human Biomonitoring

    DEFF Research Database (Denmark)

    Casteleyn, L; Dumez, B; Becker, K;

    2015-01-01

    In 2004 the European Commission and Member States initiated activities towards a harmonized approach for Human Biomonitoring surveys throughout Europe. The main objective was to sustain environmental health policy by building a coherent and sustainable framework and by increasing the comparability...... steps in European harmonization in Human Biomonitoring surveys include the establishment of a joint process for prioritization of substances to cover and biomarkers to develop, linking biomonitoring surveys with health examination surveys and with research, and coping with the diverse implementations...... data from 1844 mother-child pairs in the frame of DEMOnstration of a study to COordinate and Perform Human Biomonitoring on a European Scale (DEMOCOPHES).(1) Mercury in hair and urinary cadmium and cotinine were selected as biomarkers of exposure covered by sufficient analytical experience. Phthalate...

  19. Prompt Neutrons from Fission

    International Nuclear Information System (INIS)

    A survey is given of the present state of knowledge of the spectrum, angular distribution and number of prompt fission neutrons, as functions of incident neutron energy and individual fragment mass, for low-energy fission. The energy spectrum of prompt neutrons has been found to be of the same form (nearly Maxwellian) for many different types of fission. It has been shown that this type of spectrum is to be expected on the basis of evaporation from moving fragments, and theoretical predictions of the spectrum agree very accurately with experimental data. Some data are now available on the variation of the neutron spectrum with fragment mass and angle of emission. Only recently has it become possible to take accurate data on the angular distribution of the neutrons. It appears that the neutrons have the angular distribution to be expected if emitted almost isotropically from the moving fragments, with a possibility that some small fraction are not emitted in this way, but directly from the fissioning nuclide. Much work has been done on the variation of fission neutron number v with incident neutron energy for neutron-induced fission. The neutron number increases roughly linearly with energy, with a slope of about 0.15 n/MeV. There is now evidence that this slope changes somewhat with energy. This change must be associated with other changes in the-fission process. The most interesting recent discovery concerning fission neutrons is the strong dependence of neutron number on individual fragment mass. The data are being rapidly improved by means of the newer techniques of determining fragment mass yields from velocity and pulse-height data, and of determining neutron yields from cumulative mass yields. There is evidence of similar dependence of neutron yield on fragment mass in a number of cases. It has been suggested that this property is directly connected with the deformability of the fragments, and in particular with the near-spherical shapes of magic

  20. Analytical approaches used in stream benthic macroinvertebrate biomonitoring programs of State agencies in the United States

    Science.gov (United States)

    Carter, James L.; Resh, Vincent H.

    2013-01-01

    Biomonitoring programs based on benthic macroinvertebrates are well-established worldwide. Their value, however, depends on the appropriateness of the analytical techniques used. All United States State, benthic macroinvertebrate biomonitoring programs were surveyed regarding the purposes of their programs, quality-assurance and quality-control procedures used, habitat and water-chemistry data collected, treatment of macroinvertebrate data prior to analysis, statistical methods used, and data-storage considerations. State regulatory mandates (59 percent of programs), biotic index development (17 percent), and Federal requirements (15 percent) were the most frequently reported purposes of State programs, with the specific tasks of satisfying the requirements for 305b/303d reports (89 percent), establishment and monitoring of total maximum daily loads, and developing biocriteria being the purposes most often mentioned. Most states establish reference sites (81 percent), but classify them using State-specific methods. The most often used technique for determining the appropriateness of a reference site was Best Professional Judgment (86 percent of these states). Macroinvertebrate samples are almost always collected by using a D-frame net, and duplicate samples are collected from approximately 10 percent of sites for quality assurance and quality control purposes. Most programs have macroinvertebrate samples processed by contractors (53 percent) and have identifications confirmed by a second taxonomist (85 percent). All States collect habitat data, with most using the Rapid Bioassessment Protocol visual-assessment approach, which requires ~1 h/site. Dissolved oxygen, pH, and conductivity are measured in more than 90 percent of programs. Wide variation exists in which taxa are excluded from analyses and the level of taxonomic resolution used. Species traits, such as functional feeding groups, are commonly used (96 percent), as are tolerance values for organic pollution

  1. An improved method for estimating the neutron background in measurements of neutron capture reactions

    CERN Document Server

    Žugec, P; Colonna, N; Gunsing, F

    2016-01-01

    The relation between the neutron background in neutron capture measurements and the neutron sensitivity related to the experimental setup is examined. It is pointed out that a proper estimate of the neutron background may only be obtained by means of dedicated simulations taking into account the full framework of the neutron-induced reactions and their complete temporal evolution. No other presently available method seems to provide reliable results, in particular under the capture resonances. An improved neutron background estimation technique is proposed, the main improvement regarding the treatment of the neutron sensitivity, taking into account the temporal evolution of the neutron-induced reactions. The technique is complemented by an advanced data analysis procedure based on relativistic kinematics of neutron scattering. The analysis procedure allows for the calculation of the neutron background in capture measurements, without requiring the time-consuming simulations to be adapted to each particular sa...

  2. The World Neutron Monitor Network as a tool for the study of solar neutrons

    Directory of Open Access Journals (Sweden)

    I. G. Usoskin

    Full Text Available The use of the World Neutron Monitor Network to detect high-energy solar neutrons is discussed in detail. It is shown that the existing network can be used for the routine detection of intense sporadic solar-neutron events whenever they occur. A technique is suggested involving the weighted summation of responses of separate monitors to solar neutrons. It is demonstrated that the use of this method improves the significance of solar-neutron event detection. Different results of the simulation of the neutron-monitor sensitivity to solar neutrons have been tested with respect to their application for practical use. It is shown that the total number of neutrons with energy above 300 MeV injected from the Sun during a solar flare can be estimated directly from the time-integrated neutron-monitor response to solar neutrons without any model assumptions. The estimation technique has been developed.

  3. CHARACTERISTICS OF GAMBUSIA PUNCTATA (POECILIDAE) FOR ITS SELECTION AS BIOMONITOR IN AQUATIC TOXICOLOGY IN CUBA

    OpenAIRE

    Argota, George; Iannacone, José; Fimia, Rigoberto

    2013-01-01

    The use of natural organisms in their capacity as biomonitors allows the evaluation of the environmental conditions of aquatic ecosystems. The aim of this study was to describe the characteristics of Gambusia punctata Poey, 1854 (Poeciliidae) for selection as a biomonitor in aquatic ecotoxicology. The species was selected to be representative and monitored from 2004 to 2012 on a quarterly basis, with two of them corresponding to periods of rain and little rain outside the Almen...

  4. Elaeagnus angustifoliaL. as a Biomonitor of Heavy Metal Pollution

    OpenAIRE

    Aksoy, Ahmet

    1999-01-01

    The leaves of Elaeagnus angustifolia L. (Elaeagnaceae) were tested as a possible biomonitor of heavy metal pollution in Kayseri. Concentration of Pb, Cd and Zn were determined in unwashed and washed leaves and soils. Differences between the unwashed and washed samples varied according to the metal pollutant levels. Significant correlations were obtained between the heavy metal concentrations in surface soil and washed leaf samples. E. angustifoliawas found to be a useful biomonitor of the hea...

  5. Neutron scattering at high pressure

    OpenAIRE

    Mcwhan, D.B.

    1984-01-01

    The techniques to do elastic and inelastic neutron scattering at steady-state and pulsed sources are reviewed. The pressure cells available at most neutron scattering centres are capable of reaching pressures of the order of 5 GPa (50 kbar), and attempts to reach 10 GPa have been made. For elastic scattering, a comparison is made between neutron scattering and X-ray scattering at high pressure using rotating anode or synchrotron sources.

  6. Neutron Imaging by Boric Acid

    CERN Document Server

    Cardone, Fabio; Perconti, Walter; Petrucci, Andrea; Rosada, Alberto

    2013-01-01

    In this paper a new type of passive neutron detector based on the already existing one, CR39, is described. Its operation was verified by three different neutron sources: an Americium-Beryllium (Am241-Be) source; a TRIGA type nuclear reactor; and a fast neutron reactor called TAPIRO. The obtained results, reported here, positively confirm its operation and the accountability of the new developed detecting technique.

  7. Lichens as biomonitors of uranium in the Balkan area

    Energy Technology Data Exchange (ETDEWEB)

    Loppi, S.; Riccobono, F.; Zhang, Z.H.; Savic, S.; Ivanov, D.; Pirintsos, S.A

    2003-09-01

    Widespread contamination by depleted uranium was not detected in the Balkan area. - The contribution of the conflict of 1999 to the environmental levels of uranium in the Balkan area was evaluated by means of lichens used as biomonitors. The average U concentration found in lichens in the present study was in line with the values reported for lichens from other countries and well below the levels found in lichens collected in areas with natural or anthropogenic sources of U. Measurement of isotopic ratios {sup 235}U/{sup 238}U allowed to exclude the presence of depleted uranium. According to these results, we could not detect widespread environmental contamination by depleted uranium in the Balkan area.

  8. Algae as Bio-monitors for Damodar River Water Pollution

    Directory of Open Access Journals (Sweden)

    S. Lata Dora

    2015-12-01

    Full Text Available Damodar is an important tributary of Ganga river basin and cater the needs of industries and growing human population in the eastern part of India. Assessment of algal diversity was carried out to understand the impact of coal mining and allied industrial activities on the ecological condition of Damodar river basin. Surface water and algal samples were collected in the summer (2009 from ten sites along the Damodar River. Bio-monitoring of algal diversity showed high organic pollution load in the Damodar River. These observations were confirmed by statistical analysis. Algal community analysis and multivariate analysis showed influence of organic pollution in the river. Cluster analysis (CA identified the similarity and dissimilarity among sampling sites and discriminate the reference site from rest of the impacted sites in the Damodar river basin.

  9. Analgesic use - prevalence, biomonitoring and endocrine and reproductive effects.

    Science.gov (United States)

    Kristensen, David M; Mazaud-Guittot, Séverine; Gaudriault, Pierre; Lesné, Laurianne; Serrano, Tania; Main, Katharina M; Jégou, Bernard

    2016-07-01

    Paracetamol and NSAIDs, in particular acetylsalicylic acid (aspirin) and ibuprofen, are among the most used and environmentally released pharmaceutical drugs. The differences in international trends in the sale and consumption of mild analgesics reflect differences in marketing, governmental policies, habits, accessibility, disease patterns and the age distribution of each population. Biomonitoring indicates ubiquitous and high human exposure to paracetamol and to salicylic acid, which is the main metabolite of acetylsalicylic acid. Furthermore, evidence suggests that analgesics can have endocrine disruptive properties capable of altering animal and human reproductive function from fetal life to adulthood in both sexes. Medical and public awareness about these health concerns should be increased, particularly among pregnant women. PMID:27150289

  10. Hair Biomonitoring for Exposure to Selected Toxic Elements: An Update

    International Nuclear Information System (INIS)

    Recently, we conducted a thorough study of hair biomonitoring that has been reported worldwide and that we consider to show that hair analysis, done properly, is a very sensitive and reliable method for assessing exposure of affected individuals and population groups. This study yielded results that clearly mirrored relative environmental exposure, especially for Pb, As, Cd, and Hg. In this paper, the various questions raised about the validity and interpretation of hair trace-element content are addressed, and means to obviate them are presented and discussed. Further, examples of particularly convincing uses of hair monitoring to assess the intake--particularly of four especially hazardous environmental pollutants: As, Cd, Pb, Hg--are outlined in some detail

  11. Use of cryopreserved peripheral mononuclear blood cells in biomonitoring

    DEFF Research Database (Denmark)

    Risom, Lotte; Knudsen, Lisbeth E.

    1999-01-01

    This study was performed to investigate the effect of storing blood samples by freezing on selected biomarkers and possible implications for biomonitoring. Comparative measurements were performed in order to investigate the use of cryopreserved vs. freshly separated peripheral mononuclear blood c...... correlation of frequencies was seen when comparing fresh with cryopreserved samples. Furthermore we recommend fresh human plasma used in UDS incubation media........ We measured the DNA repair activity as dimethylsulfate induced unscheduled DNA synthesis (UDS) in PMBC incubated with either autologous plasma or fetal bovine serum (FBS). Comparison of the hprt mutant frequency by the T cell cloning assay was made in parallel. Finally the content of B....../T-lymphocytes and monocytes was measured in phytohemaglutinin (PHA)-stimulated cultures at different time intervals. The results showed a higher DNA repair activity in cryopreserved samples compared with fresh samples. We also found differences in mutant frequencies with higher values in fresh samples. A significant...

  12. Protozoa interaction with aquatic invertebrate: interest for watercourses biomonitoring.

    Science.gov (United States)

    Palos Ladeiro, M; Bigot, A; Aubert, D; Hohweyer, J; Favennec, L; Villena, I; Geffard, A

    2013-02-01

    Toxoplasma gondii, Cryptosporidium parvum, and Giardia duodenalis are human waterborne protozoa. These worldwide parasites had been detected in various watercourses as recreational, surface, drinking, river, and seawater. As of today, water protozoa detection was based on large water filtration and on sample concentration. Another tool like aquatic invertebrate parasitism could be used for sanitary and environmental biomonitoring. In fact, organisms like filter feeders could already filtrate and concentrate protozoa directly in their tissues in proportion to ambient concentration. So molluscan shellfish can be used as a bioindicator of protozoa contamination level in a site since they were sedentary. Nevertheless, only a few researches had focused on nonspecific parasitism like protozoa infection on aquatic invertebrates. Objectives of this review are twofold: Firstly, an overview of protozoa in worldwide water was presented. Secondly, current knowledge of protozoa parasitism on aquatic invertebrates was detailed and the lack of data of their biological impact was pointed out.

  13. Measurement of subcriticality using delayed neutron source combined with pulsed neutron accelerator

    International Nuclear Information System (INIS)

    A new experimental method for subcriticality measurement was developed by using delayed neutron source which is produced by external pulsed neutron source to increase accuracy of measured results by overcoming the space dependency problem which means difference of measured results in different detector position and often appeared in almost all other subcriticality measurement techniques. Experiments were performed at Kyoto University Critical Assembly (KUCA) combined with a DT accelerator to produce pulsed neutron in outside of the core repeatedly. In this method, neutron detection counts in the prompt neutron time region which are appeared just after injection of pulsed neutron are omitted, whereas neutron counts in the delayed neutron time region which are appeared after disappearance of exponential decay of the prompt neutron are adopted in analysis based on neutron source multiplication method or neutron noise analysis method; the variance to mean ratio method. In the delayed neutron time region, neutron sources to initiate fission chain reactions in subcritical state are delayed neutrons from delayed neutron precursors which are mainly produced by fission chain reactions in the prompt neutron time region, and delayed neutron precursors exist only in the fuel region, which makes possible to decrease the space dependency problem. The obtained results were compared with conventional pulsed neutron method, and it was found that the space dependency problem in subcriticality measurement can be fairly decreased by using the present new method compared with conventional one. (author)

  14. Biomonitoring of airborne particulate matter emitted from a cement plant and comparison with dispersion modelling results

    Science.gov (United States)

    Abril, Gabriela A.; Wannaz, Eduardo D.; Mateos, Ana C.; Pignata, María L.

    2014-01-01

    The influence of a cement plant that incinerates industrial waste on the air quality of a region in the province of Córdoba, Argentina, was assessed by means of biomonitoring studies (effects of immission) and atmospheric dispersion (effects of emission) of PM10 with the application of the ISC3 model (Industrial Source Complex) developed by the USEPA (Environmental Protection Agency). For the biomonitoring studies, samples from the epiphyte plant Tillandsia capillaris Ruíz & Pav. f. capillaris were transplanted to the vicinities of the cement plant in order to determine the physiological damage and heavy metal accumulation (Ca, Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb). For the application of the ISC3 model, point and area sources from the cement plant were considered to obtain average PM10 concentration results from the biomonitoring exposure period. This model permitted it to be determined that the emissions from the cement plant (point and area sources) were confined to the vicinities, without significant dispersion in the study area. This was also observed in the biomonitoring study, which identified Ca, Cd and Pb, pH and electric conductivity (EC) as biomarkers of this cement plant. Vehicular traffic emissions and soil re-suspension could be observed in the biomonitors, giving a more complete scenario. In this study, biomonitoring studies along with the application of atmospheric dispersion models, allowed the atmospheric pollution to be assessed in more detail.

  15. Incorporating traits in aquatic biomonitoring to enhance causal diagnosis and prediction.

    Science.gov (United States)

    Culp, Joseph M; Armanini, David G; Dunbar, Michael J; Orlofske, Jessica M; Poff, N LeRoy; Pollard, Amina I; Yates, Adam G; Hose, Grant C

    2011-04-01

    The linkage of trait responses to stressor gradients has potential to expand biomonitoring approaches beyond traditional taxonomically based assessments that identify ecological effect to provide a causal diagnosis. Traits-based information may have several advantages over taxonomically based methods. These include providing mechanistic linkages of biotic responses to environmental conditions, consistent descriptors or metrics across broad spatial scales, more seasonal stability compared with taxonomic measures, and seamless integration of traits-based analysis into assessment programs. A traits-based biomonitoring approach does not require a new biomonitoring framework, because contemporary biomonitoring programs gather the basic site-by-species composition matrices required to link community data to the traits database. Impediments to the adoption of traits-based biomonitoring relate to the availability, consistency, and applicability of existing trait data. For example, traits generalizations among taxa across biogeographical regions are rare, and no consensus exists relative to the required taxonomic resolution and methodology for traits assessment. Similarly, we must determine if traits form suites that are related to particular stressor effects, and whether significant variation of traits occurs among allopatric populations. Finally, to realize the potential of traits-based approaches in biomonitoring, a concerted effort to standardize terminology is required, along with the establishment of protocols to ease the sharing and merging of broad, geographical trait information. PMID:21442732

  16. MAGNETIC NEUTRON SCATTERING

    Energy Technology Data Exchange (ETDEWEB)

    ZALIZNYAK,I.A.; LEE,S.H.

    2004-07-30

    Much of our understanding of the atomic-scale magnetic structure and the dynamical properties of solids and liquids was gained from neutron-scattering studies. Elastic and inelastic neutron spectroscopy provided physicists with an unprecedented, detailed access to spin structures, magnetic-excitation spectra, soft-modes and critical dynamics at magnetic-phase transitions, which is unrivaled by other experimental techniques. Because the neutron has no electric charge, it is an ideal weakly interacting and highly penetrating probe of matter's inner structure and dynamics. Unlike techniques using photon electric fields or charged particles (e.g., electrons, muons) that significantly modify the local electronic environment, neutron spectroscopy allows determination of a material's intrinsic, unperturbed physical properties. The method is not sensitive to extraneous charges, electric fields, and the imperfection of surface layers. Because the neutron is a highly penetrating and non-destructive probe, neutron spectroscopy can probe the microscopic properties of bulk materials (not just their surface layers) and study samples embedded in complex environments, such as cryostats, magnets, and pressure cells, which are essential for understanding the physical origins of magnetic phenomena. Neutron scattering is arguably the most powerful and versatile experimental tool for studying the microscopic properties of the magnetic materials. The magnitude of the cross-section of the neutron magnetic scattering is similar to the cross-section of nuclear scattering by short-range nuclear forces, and is large enough to provide measurable scattering by the ordered magnetic structures and electron spin fluctuations. In the half-a-century or so that has passed since neutron beams with sufficient intensity for scattering applications became available with the advent of the nuclear reactors, they have became indispensable tools for studying a variety of important areas of modern

  17. Environmental lichenology: Biomonitoring trace-element air pollution

    Energy Technology Data Exchange (ETDEWEB)

    Sloof, J.E.

    1993-09-27

    Chapter 1 describes the possibilities to study trace-element air pollution in order to get insight in the character and element levels of such pollution. Chapter 2 describes two monitoring surveys using Parmelia sulcata Taylor on a national scale, in which spatial and temporal patterns of heavy metals were investigated. The surveys were carried out in 1982-1983 at 110 sampling sites and in 1986-1987 at 210 sampling sites. From these studies it was concluded that lichens are at least good qualitative biomonitors for atmospheric trace-element levels. Chapter 3 describes the response of lichens to the cesium-137 activity as a result of the Chernobyl accident, deposited by rainfall in the Netherlands. From this study it was concluded that lichens are good biomonitors for atmospheric cesium-137 activity too. Chapter 4 describes the application of factor analysis to a lichen data set from a monitoring survey on a national scale (1986-1987), for source apportionment. In Chapter 5 a field study is described on the contribution of a possible influence from the soil to element concentrations in Parmelia sulcata Taylor growing on trees in a an area with polluted soil. Chapter 6 describes a field study on the interchangeability of two tolerant lichen species (Parmelia sulcata Taylor and Lecanora conizaeoides Nyl.) in a polluted area. In Chapter 7 a field study is described in which the quantitative relationships between concentrations of cobalt, scandium and zinc in lichens and concentrations in air particulate matter and total deposition (wet and dry) were investigated. Chapter 8 describes a laboratory study on the kinetics of the uptake-and release of cadmium in a green algae species (Selenastrum capricornutum Printz), which is regarded to be representative for the algal symboint in the lichens used in this thesis. Chapter 9 presents the central conclusions of this thesis for the lichen species, elements and conditions under study. (orig./MG).

  18. Environmental lichenology: Biomonitoring trace-element air pollution

    International Nuclear Information System (INIS)

    Chapter 1 describes the possibilities to study trace-element air pollution in order to get insight in the character and element levels of such pollution. Chapter 2 describes two monitoring surveys using Parmelia sulcata Taylor on a national scale, in which spatial and temporal patterns of heavy metals were investigated. The surveys were carried out in 1982-1983 at 110 sampling sites and in 1986-1987 at 210 sampling sites. From these studies it was concluded that lichens are at least good qualitative biomonitors for atmospheric trace-element levels. Chapter 3 describes the response of lichens to the cesium-137 activity as a result of the Chernobyl accident, deposited by rainfall in the Netherlands. From this study it was concluded that lichens are good biomonitors for atmospheric cesium-137 activity too. Chapter 4 describes the application of factor analysis to a lichen data set from a monitoring survey on a national scale (1986-1987), for source apportionment. In Chapter 5 a field study is described on the contribution of a possible influence from the soil to element concentrations in Parmelia sulcata Taylor growing on trees in a an area with polluted soil. Chapter 6 describes a field study on the interchangeability of two tolerant lichen species (Parmelia sulcata Taylor and Lecanora conizaeoides Nyl.) in a polluted area. In Chapter 7 a field study is described in which the quantitative relationships between concentrations of cobalt, scandium and zinc in lichens and concentrations in air particulate matter and total deposition (wet and dry) were investigated. Chapter 8 describes a laboratory study on the kinetics of the uptake-and release of cadmium in a green algae species (Selenastrum capricornutum Printz), which is regarded to be representative for the algal symboint in the lichens used in this thesis. Chapter 9 presents the central conclusions of this thesis for the lichen species, elements and conditions under study. (orig./MG)

  19. The World Neutron Monitor Network as a tool for the study of solar neutrons

    OpenAIRE

    I. G. Usoskin; G. A. Kovaltsov; H. Kananen; P. Tanskanen

    1997-01-01

    The use of the World Neutron Monitor Network to detect high-energy solar neutrons is discussed in detail. It is shown that the existing network can be used for the routine detection of intense sporadic solar-neutron events whenever they occur. A technique is suggested involving the weighted summation of responses of separate monitors to solar neutrons. It is demonstrated that the use of this method improves the significance of solar-neutron event detection. Different results of the simulation...

  20. Magnetic correlations in oxides: Neutron diffraction and neutron depolarization study

    Indian Academy of Sciences (India)

    S M Yusuf

    2008-10-01

    We have studied magnetic correlations in several oxide materials that belong to colossal magnetoresistive, naturally occurring layered oxide showing low-dimensional magnetic ordering, solid oxide fuel cell interconnect materials, and magnetic nanoparticles using neutron diffraction and neutron depolarization techniques. In this paper, an overview of some of these results is given.

  1. Neutron spin echo spectroscopy on the spallation neutron source

    International Nuclear Information System (INIS)

    An investigation has been made into the practicability of combining the neutron spin echo and time-of-flight techniques on the Rutherford Laboratory Spallation Neutron Source. Preliminary specifications are presented for a quasielastic instrument with an energy resolution down to approximately 10 neV and an inelastic spectrometer for measuring excitation widths approximately 1 μ eV. (author)

  2. Neutron Capture and Neutron Halos

    OpenAIRE

    A.Mengoni; Otsuka, T; Nakamura, T.(International Center for Elementary Particle Physics and Department of Physics, The University of Tokyo, Tokyo, Japan); Ishihara, M.

    1996-01-01

    The connection between the neutron halo observed in light neutron rich nuclei and the neutron radiative capture process is outlined. We show how nuclear structure information such as spectroscopic factors and external components of the radial wave function of loosely bound states can be derived from the neutron capture cross section. The link between the direct radiative capture and the Coulomb dissociation process is elucidated.

  3. The intense neutron generator

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, W.B

    1966-07-01

    The presentation discusses both the economic and research contexts that would be served by producing neutrons in gram quantities at high intensities by electrical means without uranium-235. The revenue from producing radioisotopes is attractive. The array of techniques introduced by the multipurpose 65 megawatt Intense Neutron Generator project includes liquid metal cooling, superconducting magnets for beam bending and focussing, super-conductors for low-loss high-power radiofrequency systems, efficient devices for producing radiofrequency power, plasma physics developments for producing and accelerating hydrogen, ions at high intensity that are still far out from established practice, a multimegawatt high voltage D.C. generating machine that could have several applications. The research fields served relate principally to materials science through neutron-phonon and other quantum interactions as well as through neutron diffraction. Nuclear physics is served through {mu}-, {pi}- and K-meson production. Isotope production enters many fields of applied research. (author)

  4. The neutron channeling phenomenon.

    Science.gov (United States)

    Khanouchi, A; Sabir, A; Boulkheir, M; Ichaoui, R; Ghassoun, J; Jehouani, A

    1997-01-01

    Shields, used for protection against radiation, are often pierced with vacuum channels for passing cables and other instruments for measurements. The neutron transmission through these shields is an unavoidable phenomenon. In this work we study and discuss the effect of channels on neutron transmission through shields. We consider an infinite homogeneous slab, with a fixed thickness (20 lambda, with lambda the mean free path of the neutron in the slab), which contains a vacuum channel. This slab is irradiated with an infinite source of neutrons on the left side and on the other side (right side) many detectors with windows equal to 2 lambda are placed in order to evaluate the neutron transmission probabilities (Khanouchi, A., Aboubekr, A., Ghassoun, J. and Jehouani, A. (1994) Rencontre Nationale des Jeunes Chercheurs en Physique. Casa Blanca Maroc; Khanouchi, A., Sabir, A., Ghassoun, J. and Jehouani, A. (1995) Premier Congré International des Intéractions Rayonnements Matière. Eljadida Maroc). The neutron history within the slab is simulated by the Monte Carlo method (Booth, T. E. and Hendricks, J. S. (1994) Nuclear Technology 5) and using the exponential biasing technique in order to improve the Monte Carlo calculation (Levitt, L. B. (1968) Nuclear Science and Engineering 31, 500-504; Jehouani, A., Ghassoun, J. and Aboubker, A. (1994) In Proceedings of the 6th International Symposium on Radiation Physics, Rabat, Morocco). Then different geometries of the vacuum channel have been studied. For each geometry we have determined the detector response and calculated the neutron transmission probability for different detector positions. This neutron transmission probability presents a peak for the detectors placed in front of the vacuum channel. This study allowed us to clearly identify the neutron channeling phenomenon. One application of our study is to detect vacuum defects in materials. PMID:9463884

  5. The Monte Carlo Simulation of Pulsed Neutron-Fission Neutron Uranium Logging Technique%脉冲中子-裂变中子铀矿测井技术的蒙特卡罗模拟

    Institute of Scientific and Technical Information of China (English)

    王新光; 王国保; 张国光; 窦玉玲; 丰树强; 赵潇

    2013-01-01

    PNFN was a method for uranium exploration. Pulsed neutron source was used, prompt fission epithermal neutron or delayed fission thermal neutrons were detected by u-sing 3He neutron detector. Under the condition of different uranium content and porosity, the PNFN responses were simulated by using the MCNP code. The relationship between fission neutron and formation condition was studied. The obtained results showed that the larger the formation porosity, the lower the calculated uranium content. The precision of u-ranium content could be increased by the correction of scattering cross-section obtained by prompt fission epithermal or thermal neutron time decay spectrum method.%脉冲中子-裂变中子铀矿测井方法(PNFN)是采用脉冲式中子源,利用3He管中子探测器记录瞬发裂变超热中子或缓发裂变热中子,得到地层中铀矿含量信息的测井方法.利用MCNP程序模拟了不同铀含量、不同地层孔隙度地层条件下PNFN的响应,分析了瞬发裂变超热中子和缓发裂变热中子与地层铀含量和孔隙度的关系.结果表明,地层孔隙度对利用PNFN确定地层铀含量有影响,孔隙度越大,利用裂变中子直接计算得到的地层铀含量比真实含量越小.利用瞬发裂变超热中子或热中子时间衰减谱计算得到地层宏观俘获截面,对裂变中子进行校正,可以有效提高地层铀含量计算结果的准确度.

  6. Commercial applications of neutron scattering

    International Nuclear Information System (INIS)

    The fact that industry is now willing to pay the full commercial cost for certain neutron scattering experiments aimed at solving its urgent materials - related problems is a true testimony to the usefulness of neutrons as microscopic probes. This paper gives examples of such use of three techniques drawn mainly from our experience at AEA Technology Harwell Laboratory. These are diffraction to measure residual stress, small angle neutron scattering to examine hardening precipitates in ferritic steels brought about by irradiation, and reflectivity to study amorphous diamond layers deposited on silicon. In most cases it is the penetrative power of the neutron which proves to be its best asset for commercial industrial applicaitons. (author)

  7. NEUTRON IMAGING, RADIOGRAPHY AND TOMOGRAPHY

    International Nuclear Information System (INIS)

    Neutrons are an invaluable probe in a wide range of scientific, medical and commercial endeavors. Many of these applications require the recording of an image of the neutron signal, either in one-dimension or in two-dimensions. We summarize the reactions of neutrons with the most important elements that are used for their detection. A description is then given of the major techniques used in neutron imaging, with emphasis on the detection media and position readout principle. Important characteristics such as position resolution, linearity, counting rate capability and sensitivity to gamma-background are discussed. Finally, the application of a subset of these instruments in radiology and tomography is described

  8. Detectors for Time-of-Flight Fast-Neutron Radiography: 1. Neutron Counting Gas Detector

    OpenAIRE

    Dangendorf, V.; Breskin, A.; Chechik, R.; Goldberg, M; Laczko, G; Mor, I.; Reginatto, M.; Vartsky, D.

    2004-01-01

    One of our two methods for fast-neutron imaging with spectrometric capability is presented here. It is a neutron-counting technique based on a hydrogenous neutron converter coupled to Gaseous Electron Multipliers (GEM). The principles of the detection techniques and the optimization of the converter, electron amplification and the readout are described. Evaluation of the properties are derived from a experiment in a pulsed neutron beam of spectral distribution between 2 and 10 MeV

  9. Apparatus for measuring a flux of neutrons

    Science.gov (United States)

    Stringer, James L.

    1977-01-01

    A flux of neutrons is measured by disposing a detector in the flux and applying electronic correlation techniques to discriminate between the electrical signals generated by the neutron detector and the unwanted interfering electrical signals generated by the incidence of a neutron flux upon the cables connecting the detector to the electronic measuring equipment at a remote location.

  10. Assessment of the soil water balance by the combination of cosmic ray neutron sensing and eddy covariance technique in an irrigated citrus orchard (Marrakesh, Morocco)

    Science.gov (United States)

    Mroos, Katja; Baroni, Gabriele; Er-Raki, Salah; Francke, Till; Khabba, Said; Jarlan, Lionel; Hanich, Lahoucine; Oswald, Sascha E.

    2014-05-01

    Irrigation water requirement plays a crucial role in many agricultural areas and especially in arid and semi-arid landscapes. Improvements in the water management and the performance of the irrigation systems require a correct evaluation of the hydrological processes involved. However, some difficulties can arise due to the heterogeneity of the soil-plant system and of the irrigation scheme. To overcome these limitations, in this study, the soil water balance is analyzed by the combination of the Eddy Covariance technique (EC) and Cosmic Ray neutron Sensing (CRS). EC provides the measurement of the actual evapotranspiration over the area as it was presented in many field conditions. Moreover CRS showed to be a valuable approach to measure the root zone soil moisture integrated in a footprint of ~30 ha. In this way, the combination of the two methodologies should provide a better analysis of the soil water balance at field scale, as opposed to point observations, e.g. by TDR, evaporimeter and fluxmeter. Then, this could increase the capability to assess the irrigation efficiency and the agricultural water management. The study is conducted in a citrus orchard situated in a semi-arid region, 30 km southwest of Marrakesh (Morocco). The site is flat and planted with trees of same age growing in parallel rows with drip irrigation lines and application of fertilizer and pesticides. The original soil seems modified on the surface by the agricultural use, creating differences between trees, rows and lines. In addition, the drip irrigation creates also a spatial variability of the water flux distribution in the field, making this site an interesting area to test the methodology. Particular attention is given to the adaptation of the standard soil sampling campaign used for the calibration of the CRS and the introduction of a weighing function. Data were collected from June to December 2013, which corresponds to the high plant transpiration. Despite the intention of the

  11. Neutron activation analysis at the service of the worker's health: determination of arsenic

    International Nuclear Information System (INIS)

    Exposures in the workplace are generally registered when there are easily identified diseases. The major problem is that most workers are exposed to low levels of toxic chemicals that can be lethal after a long period of time, due to chronic diseases. Aiming at giving support to the Worker's Health Awareness Program of the Municipal Department of Health of Belo Horizonte, an assessment was carried out in three galvanising factories by means of airborne particulate matter collected in air filters and hair and toenail samples as biomonitors. The arsenic was determined in all matrixes from factories where gold electrodeposition process was applied. This is because arsenic salts are usually added to gold bath to improve the metal covering. The high concentration results surprised the health surveillance professionals, and alerted for the need of assessing the influence of a long-term exposure. Studies concerning galvanising process have usually been developed broaching many aspects, but so far none has pointed out the detection and measurement of other elements like arsenic. The results will support the establishment of guidelines and data basis for the next occupational program for this specific workplace. The k0-Instrumental Neutron Activation method was applied confirming to be a suitable technique on determination of arsenic in diversified matrixes. (author)

  12. Energy sliced neutron tomography using neutron resonance absorption spectrometer

    International Nuclear Information System (INIS)

    Neutron tomography was studied using a neutron resonance absorption spectrometer installed on a pulsed neutron source. The neutron resonance absorption spectroscopy (N-RAS) is a method to study the dynamics of nuclides by analyzing the Doppler broadening of their resonance spectra. N-RAS can combine with the computer tomography (CT) technique to obtain the tomogram of an object. We developed the CT reconstructions which were repeated at each time-of-flight (TOF) channel and piled up the reconstructed images in order to make the resonance spectrum over the wide energy range. Finally, we could deduce the information of nuclides and its temperature distributions in the sample non-destructively. We call this new TOF tomography technique as neutron resonance imaging (NRI).

  13. Neutron detector

    Science.gov (United States)

    Stephan, Andrew C.; Jardret; Vincent D.

    2011-04-05

    A neutron detector has a volume of neutron moderating material and a plurality of individual neutron sensing elements dispersed at selected locations throughout the moderator, and particularly arranged so that some of the detecting elements are closer to the surface of the moderator assembly and others are more deeply embedded. The arrangement captures some thermalized neutrons that might otherwise be scattered away from a single, centrally located detector element. Different geometrical arrangements may be used while preserving its fundamental characteristics. Different types of neutron sensing elements may be used, which may operate on any of a number of physical principles to perform the function of sensing a neutron, either by a capture or a scattering reaction, and converting that reaction to a detectable signal. High detection efficiency, an ability to acquire spectral information, and directional sensitivity may be obtained.

  14. Neutron Beam Characterization for Neutron Radiography Facility at the Thai Research Reactor TRR-1/M1

    International Nuclear Information System (INIS)

    The aim of this research is to characterize the present status of neutron beam coming out from the reactor core of Thai Research Reactor TRR-1/M1 through neutron radiography facility. In this study, the neutron beam profiles at different positions along the beam exit were recorded using digital imaging devices. In addition, thin foil activation technique, with and without cadmium cover, was employed to determine thermal neutron flux and Cd ratio. An acrylic step wedge was exposed to neutron at different time. In parallel to image construction, neutron detection was carried out using a BF3 gas-filled detector. Then, the image intensities at particular thicknesses were normalized by neutron counts from the BF3 detector to determine relative neutron intensity. The obtained information of neutron beam characterization will be useful not only for monitoring the present status of neutron radiography facility but also for determining the optimum exposure conditions for particular samples in the future.

  15. Neutron scattering in Australia

    International Nuclear Information System (INIS)

    Neutron scattering techniques have been part of the Australian scientific research community for the past three decades. The High Flux Australian Reactor (HIFAR) is a multi-use facility of modest performance that provides the only neutron source in the country suitable for neutron scattering. The limitations of HIFAR have been recognized and recently a Government initiated inquiry sought to evaluate the future needs of a neutron source. In essence, the inquiry suggested that a delay of several years would enable a number of key issues to be resolved, and therefore a more appropriate decision made. In the meantime, use of the present source is being optimized, and where necessary research is being undertaken at major overseas neutron facilities either on a formal or informal basis. Australia has, at present, a formal agreement with the Rutherford Appleton Laboratory (UK) for access to the spallation source ISIS. Various aspects of neutron scattering have been implemented on HIFAR, including investigations of the structure of biological relevant molecules. One aspect of these investigations will be presented. Preliminary results from a study of the interaction of the immunosuppressant drug, cyclosporin-A, with reconstituted membranes suggest that the hydrophobic drug interdigitated with lipid chains

  16. Neutron scattering in Australia

    Energy Technology Data Exchange (ETDEWEB)

    Knott, R.B. [Australian Nuclear Science and Technology Organisation, Menai (Australia)

    1994-12-31

    Neutron scattering techniques have been part of the Australian scientific research community for the past three decades. The High Flux Australian Reactor (HIFAR) is a multi-use facility of modest performance that provides the only neutron source in the country suitable for neutron scattering. The limitations of HIFAR have been recognized and recently a Government initiated inquiry sought to evaluate the future needs of a neutron source. In essence, the inquiry suggested that a delay of several years would enable a number of key issues to be resolved, and therefore a more appropriate decision made. In the meantime, use of the present source is being optimized, and where necessary research is being undertaken at major overseas neutron facilities either on a formal or informal basis. Australia has, at present, a formal agreement with the Rutherford Appleton Laboratory (UK) for access to the spallation source ISIS. Various aspects of neutron scattering have been implemented on HIFAR, including investigations of the structure of biological relevant molecules. One aspect of these investigations will be presented. Preliminary results from a study of the interaction of the immunosuppressant drug, cyclosporin-A, with reconstituted membranes suggest that the hydrophobic drug interdigitated with lipid chains.

  17. Development of a technique using MCNPX code for determination of nitrogen content of explosive materials using prompt gamma neutron activation analysis method

    Energy Technology Data Exchange (ETDEWEB)

    Nasrabadi, M.N., E-mail: mnnasrabadi@ast.ui.ac.ir [Department of Nuclear Engineering, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Bakhshi, F.; Jalali, M.; Mohammadi, A. [Department of Nuclear Engineering, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of)

    2011-12-11

    Nuclear-based explosive detection methods can detect explosives by identifying their elemental components, especially nitrogen. Thermal neutron capture reactions have been used for detecting prompt gamma 10.8 MeV following radioactive neutron capture by {sup 14}N nuclei. We aimed to study the feasibility of using field-portable prompt gamma neutron activation analysis (PGNAA) along with improved nuclear equipment to detect and identify explosives, illicit substances or landmines. A {sup 252}Cf radio-isotopic source was embedded in a cylinder made of high-density polyethylene (HDPE) and the cylinder was then placed in another cylindrical container filled with water. Measurements were performed on high nitrogen content compounds such as melamine (C{sub 3}H{sub 6}N{sub 6}). Melamine powder in a HDPE bottle was placed underneath the vessel containing water and the neutron source. Gamma rays were detected using two NaI(Tl) crystals. The results were simulated with MCNP4c code calculations. The theoretical calculations and experimental measurements were in good agreement indicating that this method can be used for detection of explosives and illicit drugs.

  18. Advanced materials characterization and modeling using synchrotron, neutron, TEM, and novel micro-mechanical techniques - A European effort to accelerate fusion materials development

    DEFF Research Database (Denmark)

    Linsmeier, Ch.; Fu, C.-C.; Kaprolat, A.;

    2013-01-01

    For the realization of fusion as an energy source, the development of suitable materials is one of the most critical issues. The required material properties are in many aspects unique compared to the existing solutions, particularly the need for necessary resistance to irradiation with neutrons ...

  19. Power measurement in the 7A2 configuration of the RP-0 reactor using the neutron noise technique connected to a compensated ionized chamber

    International Nuclear Information System (INIS)

    Results of the neutron noise measurements carried out in the 7A2 configuration of the RP-0 reactor using the BC3 rod to reach criticality are presented. These measurements were carried out using a compensated ionized chamber (CIC) located at E2 position. Finally, potential calibration of the march chamber 4 from the reactor instrumentation is presented

  20. Notes on neutron flux measurement

    International Nuclear Information System (INIS)

    The main purpose of this work is to get an useful guide to carry out topical neutron flux measurements. Although the foil activation technique is used in the majority of the cases, other techniques, such as those based on fission chambers and self-powered neutron detectors, are also shown. Special interest is given to the description and application of corrections on the measurement of relative and absolute induced activities by several types of detectors (scintillators, G-M and gas proportional counters). The thermal arid epithermal neutron fluxes, as determined in this work, are conventional or effective (West cots fluxes), which are extensively used by the reactor experimentalists; however, we also give some expressions where they are related to the integrated neutron fluxes, which are used in neutron calculations. (Author) 16 refs

  1. Neutron imaging in materials science

    Directory of Open Access Journals (Sweden)

    Nikolay Kardjilov

    2011-06-01

    Full Text Available Neutron imaging is a non-destructive technique that can reveal the interior of many materials and engineering components and also probe magnetic fields. Within the past few years, several new imaging modes have been introduced that extend the scope of neutron imaging beyond conventional neutron attenuation imaging, yielding both 2- and 3D information about properties and phenomena inaccessible until now. We present an overview of the most important advances in the application of neutron imaging in materials research with a focus on novel techniques such as energy-selective imaging, interferometric imaging with phase gratings, and polarized-neutron imaging. Examples given include the investigation of fluid dynamics in fuel cells, materials phases and structural heterogeneities, distribution of strains, and magnetic structures or phase transitions.

  2. Epiphytic Moss as a Biomonitor for Nitrogen Deposition

    Science.gov (United States)

    Rolfe, T.; Deakova, T.; Shortlidge, E.; Rao, M.; Rosenstiel, T. N.; Rice, A. L.; George, L. A.

    2014-12-01

    Tracking nitrogen (N) deposition patterns is important for understanding how anthropogenic sources of nitrogen affect natural habitats, human health, and for evaluating computer models of future N deposition. It can also aid in tracking and modeling anthropogenic fossil fuel emissions. This pilot study investigated the use of Orthotrichum lyellii, a common urban epiphytic moss, as a possible bioindicator for N deposition through the analysis of total moss N content and N isotopic fractionation ( δ15N) for evaluating N sources. In the spring/summer of 2013 we collected 168 O. lyellii samples from the trunks of deciduous trees in 53 locations in the Portland metropolitan area. In the winter of 2013-14, we resampled the same locations to investigate the effect of seasonality. The averaged summer moss N content were plotted against a land use regression model (LUR) developed by taking NOx samples from 144 sites in the Portland area within the Urban Growth Boundary. The correlation between moss N and modeled NO2 was found to be significant at p moss samples N content ranged between 0.71% and 3.36% (mean of 1.87%), the δ15N ranged -8.97‰ and 11.78‰ (mean of -0.91‰). Moss winter N content ranged between .77% and 3.12% (mean of 1.71%), and the δ15N ranged -10.40‰ and 10.27‰ (mean of -3.73‰). The average values for %N and δ15N fall within the range of previous studies in other moss samples, however the maximum values are higher than what other studies have typically found for both %N and δ15N. A significant correlation between δ15N and %N was found (r = 0.67). The moss samples showed a similar pattern of higher N content and δ15N near the urban center decreasing with distance from major roadways and other significant sources of fossil fuel derived NOx. These results indicated the sensitivity of O.lyellii to N and the potential for its use as a biomonitor. With sufficient sampling density, using O. lyellii as an inexpensive biomonitor to evaluate local

  3. Atmospheric neutrons

    International Nuclear Information System (INIS)

    Additional calibrations of the University of California double-scatter neutron and additional analysis corrections lead to the slightly changed neutron fluxes reported here. The theoretical angular distributions of Merker (1975) are in general agreement with our experimental fluxes but do not give the peaks for vertical upward and downward moving neutrons. The theoretical neutron escape current J2/sub pi/ (Merker, 1972; Armstrong et al., 1973) is in agreement with the experimental values from 10 to 100 MeV. Our experimental fluxes agree with those of the Kanbach et al. (1974) in the overlap region from 70 to 100 MeV

  4. Neutron Albedo

    CERN Document Server

    Ignatovich, V K

    2005-01-01

    A new, algebraic, method is applied to calculation of neutron albedo from substance to check the claim that use of ultradispersive fuel and moderator of an active core can help to gain in size and mass of the reactor. In a model of isotropic distribution of incident and reflected neutrons it is shown that coherent scattering on separate grains in the case of thermal neutrons increases transport cross section negligibly, however it decreases albedo from a wall of finite thickness because of decrease of substance density. A visible increase of albedo takes place only for neutrons with wave length of the order of the size of a single grain.

  5. DBS-platform for biomonitoring and toxicokinetics of toxicants: proof of concept using LC-MS/MS analysis of fipronil and its metabolites in blood

    Science.gov (United States)

    Raju, Kanumuri Siva Rama; Taneja, Isha; Rashid, Mamunur; Sonkar, Ashish Kumar; Wahajuddin, Muhammad; Singh, Sheelendra Pratap

    2016-03-01

    A simple, sensitive and high throughput LC-MS/MS method was developed and validated for quantification of fipronil, fipronil sulfone and fipronil desulfinyl in rat and human dried blood spots (DBS). DBS samples were prepared by spiking 10 μl blood on DMPK-C cards followed by drying at room temperature. The whole blood spots were then punched from the card and extracted using acetonitrile. The total chromatographic run time of the method was only 2 min. The lower limit of quantification of the method was 0.1 ng/ml for all the analytes. The method was successfully applied to determine fipronil desulfinyl in DBS samples obtained from its toxicokinetic study in rats following intravenous dose (1 mg/kg). In conclusion, the proposed DBS methodology has significant potential in toxicokinetics and biomonitoring studies of environmental toxicants. This microvolume DBS technique will be an ideal tool for biomonitoring studies, particularly in paediatric population. Small volume requirements, minimally invasive blood sampling method, easier storage and shipping procedure make DBS a suitable technique for such studies. Further, DBS technique contributes towards the principles of 3Rs resulting in significant reduction in the number of rodents used and refinement in sample collection for toxicokinetic studies.

  6. Outline of spallation neutron source engineering

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Noboru [Center for Neutron Science, Tokai Research Establishment, Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan)

    2001-01-01

    Slow neutrons such as cold and thermal neutrons are unique probes which can determine structures and dynamics of condensed matter in atomic scale. The neutron scattering technique is indispensable not only for basic sciences such as condensed matter research and life science, but also for basic industrial technology in 21 century. It is believed that to survive in the science-technology competition in 21 century would be almost impossible without neutron scattering. However, the intensity of neutrons presently available is much lower than synchrotron radiation sources, etc. Thus, R and D of intense neutron sources become most important. The High-Intensity Proton Accelerator Project is now being promoted jointly by Japan Atomic Energy Research Institute and High Energy Accelerator Research Organization, but there has so far been no good text which covers all the aspects of pulsed spallation neutron sources. The present review was prepare aiming at giving a better understanding on pulsed spallation neutron sources not only to neutron source researchers but also more widely to neutron scattering researchers and accelerator scientists in this field. The contents involve, starting from what is neutron scattering and what neutrons are necessary for neutron scattering, what is the spallation reaction, how to produce neutrons required for neutron scattering more efficiently, target-moderator-reflector neutronics and its engineering, shielding, target station, material issues, etc. The author have engaged in R and D of pulsed apallation neutron sources and neutron scattering research using them over 30 years. The present review is prepared based on the author's experiences with useful information obtained through ICANS collaboration and recent data from the JSNS (Japanese Spallation Neutron Source) design team. (author)

  7. Suitability of Tillandsia usneoides and Aechmea fasciata for biomonitoring toxic elements under tropical seasonal climate.

    Science.gov (United States)

    Giampaoli, Patricia; Wannaz, Eduardo D; Tavares, Armando R; Domingos, Marisa

    2016-04-01

    Aechmea fasciata was evaluated for the first time as a biomonitor of toxic elements, in comparison to the biomonitoring capacity of Tillandsia usneoides, a well-established biomonitor bromeliad species. Plants of both species were exposed to air pollutants from industrial, urban, and agricultural sources, under the tropical seasonal climate, from June/2011 to April/2013, in five sites of São Paulo State, Brazil, for 8 consecutive exposure periods of 12 weeks each. The levels of essential and non-essential elements, including trace metals, were quantified at the end of each exposure. T. usneoides and A. fasciata indicated N, Fe, Zn, Co, Cr, and V as air contaminants in the studied sites, during wet and dry seasons and both species were recommended for qualitative biomonitoring. Concentration levels of N, Ca, S, Fe, Zn, Cu, B, Co, and Ni were significantly higher in T. usneoides than in A. fasciata. However, A. fasciata showed a higher effective retention capacity of Ni, Pb, V, Cu, Fe, Cr, and Co during field exposure, as indicated by the estimate of enrichment factor relative to basal concentrations. This species is more suitable for detecting the atmospheric pollution level of those metals than the T. usneoides. Both species indicated adequately the seasonal differences in the pollution levels of several elements, but T. usneoides presented higher ability for biomonitoring the spatial variations and for indicating more properly the sources of each element in the studied region than the A. fasciata. PMID:26844661

  8. Safety techniques in the change of nuclear systems. Radiation protection at spallation neutron sources and transmutation facilities; Sicherheitstechnik im Wandel Nuklearer Systeme. Strahlenschutz bei Spallationsneutronenquellen und Transmutationsanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Nuenighoff, Kay

    2009-07-01

    To push the boundary towards higher neutron fluxes concepts based on spallation reactions have been discussed. Here neutrons are produced by bombarding a heavy metal target (e.g. mercury, tungsten, or tantalum) with high energetic protons. Up to now such facilities could not be realised because of the high power particle accelerators needed. Recent developments of the accelerator technology open the possibility of construction and operating proton accelerators in the MW region. This is demonstrated by construction and commissioning of two MW spallation neutron sources, namely SNS (Oak Ridge, Tennessee, USA) with a power of 1.4 MW and J-PARC (Japan) with 1 MW. The realisation of proton accelerators at this power level will open the way towards energy amplifiers, as proposed e.g. by Carlo Rubbia. Such a facility will not only produce electric power. Furthermore longliving radionuclides can be transmutated into shortlived or even stable nuclides by neutron induced nuclear reactions. A mitigation of the problem of nuclear waste disposal. The above discussed developments prove that accelerators are not only constructed for research, moreover application of these technology became state of the art. With the emergence of particle accelerators in the MW region, radiation protection is confronted with new kind of problems to be solved. Especially the higher kinetic energies of the primary beam particles requires modification and expansion of computer programs well known in nuclear engineering. In contrast to nuclear reactors with kinetic energies up to 2-3 MeV, in spallation reaction secondary particles up to the incident energy in the GeV region will be produced. Problems related to radiation protection have to be considered in an energy range three orders of magnitude higher than known from nuclear reactors. In this thesis existing computer codes are compared and validated with data from selected experiments. Questions concerning radiation protection covers a broad range

  9. Material examination by neutron radiography

    International Nuclear Information System (INIS)

    Neutron radiography as a non-destructive testing technique has played a prominent role in the development of fuel for research and power reactors; studying of dimensional changes due to irradiation; inspection of corrosion in airframe structures and propeller blades; detection of light components and materials in explosive an investigation of diffusion of water into building materials etc. The development of neutron radiography facility by extracting a beam of thermal neutrons through a radial beam port around the Pakistan Research Reactor-1 is described. Graphite block of 30 cm thickness and bismuth block of 25 cm thickness have been used to boost-up thermal neutrons flux level and filter out high energy gamma radiation from the beam respectively. Thermal neutron flux level of the order of 1.06x10/sup 6/ n.cm/sup -2/. s/sup -1/ and a neutron to gamma ratio of the order of 10/sup 5/ n.cm/sup -2/.mR/sup -1/ have been measured at the object position which make the facility useful for investigation of material characteristics an properties applying direct neutron radiography method. The facility has been subjected to modifications and changes in order to enhance thermal neutron flux level and reduce the exposure time for better image quality at the object position. The use of beam purity and sensitivity indicators for determining the beam constituents and resolution of the technique is discussed. Visibility of holes under the lead and acrylic step wedges categorize the facility for direct applications. Neutron cross-sections for different metallic as well as composite materials have been determined by applying neutron radiographic technique. The use of neutron radiography as a complimentary technique to ensure the quality of nuclear fuel in addition to other applications like detection of light components in explosives and pyrotechnic devices is investigated. Detection of corrosion in aluminum joints, deformation in aeronautical components and honeycomb structures is

  10. Slow neutron leakage spectra from spallation neutron sources

    International Nuclear Information System (INIS)

    An efficient technique is described for Monte Carlo simulation of neutron beam spectra from target-moderator-reflector assemblies typical of pulsed spallation neutron sources. The technique involves the scoring of the transport-theoretical probability that a neutron will emerge from the moderator surface in the direction of interest, at each collision. An angle-biasing probability is also introduced which further enhances efficiency in simple problems. These modifications were introduced into the VIM low energy neutron transport code, representing the spatial and energy distributions of the source neutrons approximately as those of evaporation neutrons generated through the spallation process by protons of various energies. The intensity of slow neutrons leaking from various reflected moderators was studied for various neutron source arrangements. These include computations relating to early measurements on a mockup-assembly, a brief survey of moderator materials and sizes, and a survey of the effects of varying source and moderator configurations with a practical, liquid metal cooled uranium source Wing and slab, i.e., tangential and radial moderator arrangements, and Be vs CH2 reflectors are compared. Results are also presented for several complicated geometries which more closely represent realistic arrangements for a practical source, and for a subcritical fission multiplier such as might be driven by an electron linac. An adaptation of the code was developed to enable time dependent calculations, and investigated the effects of the reflector, decoupling and void liner materials on the pulse shape

  11. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1993-12-31

    A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

  12. Hg localisation in Tillandsia usneoides L. (Bromeliaceae), an atmospheric biomonitor

    Energy Technology Data Exchange (ETDEWEB)

    Filho, G.M.A. [Instituto de Pesquisas Jardim Botanico do Rio de Janeiro (Brazil). Programa Zona Costeira; Andrade, L.R.; Farina, M. [Cidade Universitaria, Rio de Janeiro (Brazil). Instituto de Ciencias Biomedicas, Departamento de Anatomia; Malm, O. [Cidade Universitaria, Rio de Janeiro (Brazil). Instituto de Biofisica Carlos Chagas Filho, Laboratorio de Radioisotopos Eduardo Penna Franca

    2002-07-01

    The Spanish moss, Tillandsia usneoides, has been applied as an atmospheric biomonitor of Hg contamination, although the mechanism of metal plant accumulation has not been understood until now. In the present work, analytical scanning electron microscopy (SEM) was used to localize Hg in T. usneoides exposed to a Hg-air-contaminated area during 15 days. After this period, Hg was determined by the flow injection mercury system, and plants were prepared for SEM observation and energy-dispersive X-ray analysis. A concentration of 2702{+-}318{mu}g Hgg{sup -1} was determined in exposed plants. The presented microanalytical results demonstrated that Hg was partly associated with atmospheric particles deposited upon the plant surface, but it was highly absorbed by the scales, stem and leaves surfaces and less absorbed by epidermal cells of T. usneoides. No Hg was detected in mesophyll parenchyma or in vascular system cells. The great surface adsorption area provided by the scales, in addition to the characteristics of T. usneoides morphology, especially of the node region, are suggested to confer the great capability of T. usneoides in Hg holding. (author)

  13. Evaluation of a Home Biomonitoring Autonomous Mobile Robot

    Science.gov (United States)

    Dorronzoro Zubiete, Enrique; Nakahata, Keigo; Imamoglu, Nevrez; Sekine, Masashi; Sun, Guanghao; Gomez, Isabel; Yu, Wenwei

    2016-01-01

    Increasing population age demands more services in healthcare domain. It has been shown that mobile robots could be a potential solution to home biomonitoring for the elderly. Through our previous studies, a mobile robot system that is able to track a subject and identify his daily living activities has been developed. However, the system has not been tested in any home living scenarios. In this study we did a series of experiments to investigate the accuracy of activity recognition of the mobile robot in a home living scenario. The daily activities tested in the evaluation experiment include watching TV and sleeping. A dataset recorded by a distributed distance-measuring sensor network was used as a reference to the activity recognition results. It was shown that the accuracy is not consistent for all the activities; that is, mobile robot could achieve a high success rate in some activities but a poor success rate in others. It was found that the observation position of the mobile robot and subject surroundings have high impact on the accuracy of the activity recognition, due to the variability of the home living daily activities and their transitional process. The possibility of improvement of recognition accuracy has been shown too. PMID:27212940

  14. Evaluation of a Home Biomonitoring Autonomous Mobile Robot

    Directory of Open Access Journals (Sweden)

    Enrique Dorronzoro Zubiete

    2016-01-01

    Full Text Available Increasing population age demands more services in healthcare domain. It has been shown that mobile robots could be a potential solution to home biomonitoring for the elderly. Through our previous studies, a mobile robot system that is able to track a subject and identify his daily living activities has been developed. However, the system has not been tested in any home living scenarios. In this study we did a series of experiments to investigate the accuracy of activity recognition of the mobile robot in a home living scenario. The daily activities tested in the evaluation experiment include watching TV and sleeping. A dataset recorded by a distributed distance-measuring sensor network was used as a reference to the activity recognition results. It was shown that the accuracy is not consistent for all the activities; that is, mobile robot could achieve a high success rate in some activities but a poor success rate in others. It was found that the observation position of the mobile robot and subject surroundings have high impact on the accuracy of the activity recognition, due to the variability of the home living daily activities and their transitional process. The possibility of improvement of recognition accuracy has been shown too.

  15. Biomonitoring of metal contamination in estuarine ecosystem using seagrass.

    Science.gov (United States)

    Ahmad, Faridahanim; Azman, Shamila; Said, Mohd Ismid Mohd; Baloo, Lavania

    2015-01-01

    Metals concentrations (As, Cd, Cu, Hg and Pb) in seawater, sediment and the seagrass (Enhalus acoroides) were analysed at Pulai River estuary, Johor Straits, Malaysia. In this research, Enhalus acoroides was used in order to find it's efficiency in up taking metals with a role in phytoremediation. Seawater, sediment and Enhalus acoroides samples were collected, and data of Pearson's correlation coefficients were analysed using SPSS 16 software. Results show that lead levels were the highest metal content in Enhalus acoroides (202 ± 102 μg/gDW), seawater (268 ± 190 μg/L) and sediment (248 ± 218 μg/gDW), compared to other metals. There was a positive correlation for metal concentrations between Enhalus acoroides and sediment, but no correlation was found between Enhalus acoroides with seawater at estuarine area may be caused by inconsistent metal concentrations in seawater due to the influences of tidal changes and stormy waves. This indicates that Enhalus acoroides is a species possessing the capabilities to uptake metals from sediment, and suitable to act as both a phytoremediator and biomonitor in estuarine ecosystems due to sharp sensitivity to variation in the environment. PMID:26029376

  16. Chemometrics in biomonitoring: Distribution and correlation of trace elements in tree leaves.

    Science.gov (United States)

    Deljanin, Isidora; Antanasijević, Davor; Bjelajac, Anđelika; Urošević, Mira Aničić; Nikolić, Miroslav; Perić-Grujić, Aleksandra; Ristić, Mirjana

    2016-03-01

    The concentrations of 15 elements were measured in the leaf samples of Aesculus hippocastanum, Tilia spp., Betula pendula and Acer platanoides collected in May and September of 2014 from four different locations in Belgrade, Serbia. The objective was to assess the chemical characterization of leaf surface and in-wax fractions, as well as the leaf tissue element content, by analyzing untreated, washed with water and washed with chloroform leaf samples, respectively. The combined approach of self-organizing networks (SON) and Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE) aided by Geometrical Analysis for Interactive Aid (GAIA) was used in the interpretation of multiple element loads on/in the tree leaves. The morphological characteristics of the leaf surfaces and the elemental composition of particulate matter (PM) deposited on tree leaves were studied by using scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) detector. The results showed that the amounts of retained and accumulated element concentrations depend on several parameters, such as chemical properties of the element and morphological properties of the leaves. Among the studied species, Tilia spp. was found to be the most effective in the accumulation of elements in leaf tissue (70% of the total element concentration), while A. hippocastanum had the lowest accumulation (54%). After water and chloroform washing, the highest percentages of removal were observed for Al, V, Cr, Cu, Zn, As, Cd and Sb (>40%). The PROMETHEE/SON ranking/classifying results were in accordance with the results obtained from the GAIA clustering techniques. The combination of the techniques enabled extraction of additional information from datasets. Therefore, the use of both the ranking and clustering methods could be a useful tool to be applied in biomonitoring studies of trace elements. PMID:26748000

  17. Neutron tubes

    Science.gov (United States)

    Leung, Ka-Ngo; Lou, Tak Pui; Reijonen, Jani

    2008-03-11

    A neutron tube or generator is based on a RF driven plasma ion source having a quartz or other chamber surrounded by an external RF antenna. A deuterium or mixed deuterium/tritium (or even just a tritium) plasma is generated in the chamber and D or D/T (or T) ions are extracted from the plasma. A neutron generating target is positioned so that the ion beam is incident thereon and loads the target. Incident ions cause D-D or D-T (or T-T) reactions which generate neutrons. Various embodiments differ primarily in size of the chamber and position and shape of the neutron generating target. Some neutron generators are small enough for implantation in the body. The target may be at the end of a catheter-like drift tube. The target may have a tapered or conical surface to increase target surface area.

  18. Detection of microorganisms in culture medium through the neutron radiographic technique; Deteccao de microorganismos em meios de cultura pela tecnica de neutrongrafia

    Energy Technology Data Exchange (ETDEWEB)

    Wacha, Reinaldo

    1999-05-01

    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 10{sup 5} n.cm{sup -2}.s{sup -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 ({eta}, {alpha}) 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)

  19. The application of the multiple transient technique for the experimental determination of the relative abundances and decay constants of delayed neutrons of the IPEN/MB-01 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Adimir dos [Instituto de Pesquisas Energeticas e Nucleares, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, Sao Paulo, SP 05508-000 (Brazil)]. E-mail: asantos@ipen.br; Diniz, Ricardo [Instituto de Pesquisas Energeticas e Nucleares, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, Sao Paulo, SP 05508-000 (Brazil); Jerez, Rogerio [Instituto de Pesquisas Energeticas e Nucleares, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, Sao Paulo, SP 05508-000 (Brazil); Mai, Luiz Antonio [Instituto de Pesquisas Energeticas e Nucleares, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, Sao Paulo, SP 05508-000 (Brazil); Yamaguchi, Mitsuo [Instituto de Pesquisas Energeticas e Nucleares, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, Sao Paulo, SP 05508-000 (Brazil)

    2006-07-15

    An in-pile experiment for the determination of the relative abundances and decay constants of delayed neutrons has been successfully performed at the IPEN/MB-01 research reactor facility. The experimental data are of good quality and can be used to validate theoretical predictions of the delayed neutron group constants based on the current knowledge of the fission products yields and emission probabilities for known precursors. The theory/experiment comparison shows that the current release of ENDF/B-VI, namely release 8, shows severe discrepancies in both relative abundances and in its first decay constant. The version revised at LANL shows very good progress in both aspects. JENDL3.3 shows the best performance in the C/E comparison. One of the main achievements of the experiment was the consistency of the measured first decay constant to that of {sup 87}Br. Finally, it is also shown preliminary experimental results for an eight-group model.

  20. Survey of nuclear parameters from the TRIGA Mark I IPR R1 Brazilian reactor with concentric configuration aiming the application of K0 neutron activation technique

    International Nuclear Information System (INIS)

    This research intended to determine the nuclear parameters a, f, spectral index and neutron temperature in several irradiations positions of the TRIGA Mark 1 IPR-R1 reactor, for use on the parametric method K0 in the CDTN. K0 is a monostandard method of neutron activation analysis. It is, on the whole, experimentally simple, flexible and an important tool for accurate and convenient standardization in instrumental multi-element analysis. At the time the parameters were determined at the rotatory rack, lower layer and in the central thimble: alpha was calculated applying the three bare monitor method using 197Au, 94Zr and 96Zr; f determination was done according to the bare bi-isotopic method; neutron temperature was calculated through the direct method using 176Lu, 94Zr, 96Zr and 197Au and the Westcott's g(Tn) function for the 176Lu was calculated and the result was interpolated in the Grintakis and Kim (1975) Table, determining the neutron temperature. The procedure to check the parameters consisted in using standard solutions of Au (metal foil, NBS), Lu (LuO2, Johnson Mattey Company - JMC) and Zr (ZrO2 and metal foil, Johnson Mattey Company 99,99% and Zry - 4: 98,14% of Zr, National Bureau of Standard- NBS). Several certified reference materials and two samples of intercomparisons (samples of sediment of the IAEA/ARCAL XXVI project) have been analysed by means of k0- INAA in order to verify the efficiency of the method and the quality of the parameters. The certified reference materials were: GXR-2, GXR-5 and GXR-6 of the United States Geological Survey (USGS) and Soil-5, Soil-7 and SL-1 of the International Atomic Energy Agency (IAEA). (author)