WorldWideScience

Sample records for neutron occupation numbers

  1. Natural occupation numbers: When do they vanish?

    NARCIS (Netherlands)

    Giesbertz, K.J.H.; Van Leeuwen, R.

    The non-vanishing of the natural orbital (NO) occupation numbers of the one-particle density matrix of many-body systems has important consequences for the existence of a density matrix-potential mapping for nonlocal potentials in reduced density matrix functional theory and for the validity of the

  2. Occupation number dependence of molecular energy levels

    International Nuclear Information System (INIS)

    Giambiagi, M.S. de; Giambiagi, M.; Ferreira, R.

    1977-08-01

    The Roothaan expression for the energy of a closed-shell molecular system is generalized in order to apply to open shells. A continuous variation from 0 to 2 is supposed for each level's occupation number, extending to this range tbe correction due to the spurious repulsion appearing in the half-electron method. The characteristic equations of the Xα method are applied to the energy expressions. The one level case is discussed in detail. Ionic and excited states of the 1,3 transbutadiene π system are analyzed

  3. Neutron Orbital Occupancies in the A∼100 Region

    International Nuclear Information System (INIS)

    Borello-Lewin, T.; Duarte, J. L. M.; Horodynski-Matsushigue, L. B.; Rodrigues, C. L.; Rodrigues, M. R. D.; Ukita, G. M.

    2009-01-01

    The evolutive behavior of the experimental neutron orbital occupancies, along isotopic chains in the A∼100, is taken as a microscopic indicator of the transition. No increase of the vlg 7/2 orbital occupancy was revealed for N>55, contrary previous expectations that interpreted the increase of deformation as due mainly to the n-p interaction in the SOP orbitals.

  4. Tidal Love Numbers of Neutron Stars

    International Nuclear Information System (INIS)

    Hinderer, Tanja

    2008-01-01

    For a variety of fully relativistic polytropic neutron star models we calculate the star's tidal Love number k 2 . Most realistic equations of state for neutron stars can be approximated as a polytrope with an effective index n ∼ 0.5-1.0. The equilibrium stellar model is obtained by numerical integration of the Tolman-Oppenheimer-Volkhov equations. We calculate the linear l = 2 static perturbations to the Schwarzschild spacetime following the method of Thorne and Campolattaro. Combining the perturbed Einstein equations into a single second-order differential equation for the perturbation to the metric coefficient g tt and matching the exterior solution to the asymptotic expansion of the metric in the star's local asymptotic rest frame gives the Love number. Our results agree well with the Newtonian results in the weak field limit. The fully relativistic values differ from the Newtonian values by up to ∼24%. The Love number is potentially measurable in gravitational wave signals from inspiralling binary neutron stars.

  5. France's Administrative Tertiary: Stable Numbers for Occupations in Flux.

    Science.gov (United States)

    Liaroutzos, Olivier; Meriot, Sylvie-Anne

    1995-01-01

    During the past decade, the number of jobs in France's administrative service sector has remained stable. General administrative work has become more infrequent; however, the basic occupations of secretary and accountancy have been maintained. Although the number of typists has declined, the number of "secretarial" jobs has increased…

  6. Occupational dose due to neutrons in medical linear accelerators

    International Nuclear Information System (INIS)

    Larcher, Ana M.; Bonet Duran, Stella M.; Lerner, Ana M.

    2000-01-01

    This paper describes a semi-empirical method to calculate the occupational dose due to neutrons and capture gamma rays in medical linear accelerators. It compares theoretical dose values with measurements performed in several 15 MeV medical accelerators installed in the country. Good agreement has been found between calculations made using the model and dose measurements, except for those accelerator rooms in which the maze length was shorter than the postulated tenth value distance. For those cases the model seems to overestimate neutron dose. The results demonstrate that the semi-empirical model is a good tool for quick and conservative shielding calculations for radiation protection purposes. Nevertheless, it is necessary to continue with the measurements in order to perform a more accurate validation of the model. (author)

  7. MATERIAL COMPOSITIONS AND NUMBER DENSITIES FOR NEUTRONICS CALCULATIONS

    International Nuclear Information System (INIS)

    D. A. Thomas

    1996-01-01

    The purpose of this analysis is to calculate the number densities and isotopic weight percentages of the standard materials to be used in the neutronics (criticality and radiation shielding) evaluations by the Waste Package Development Department. The objective of this analysis is to provide material number density information which can be referenced by future neutronics design analyses, such as for those supporting the Conceptual Design Report

  8. Gentile statistics with a large maximum occupation number

    International Nuclear Information System (INIS)

    Dai Wusheng; Xie Mi

    2004-01-01

    In Gentile statistics the maximum occupation number can take on unrestricted integers: 1 1 the Bose-Einstein case is not recovered from Gentile statistics as n goes to N. Attention is also concentrated on the contribution of the ground state which was ignored in related literature. The thermodynamic behavior of a ν-dimensional Gentile ideal gas of particle of dispersion E=p s /2m, where ν and s are arbitrary, is analyzed in detail. Moreover, we provide an alternative derivation of the partition function for Gentile statistics

  9. Natural occupation numbers in two-electron quantum rings.

    Science.gov (United States)

    Tognetti, Vincent; Loos, Pierre-François

    2016-02-07

    Natural orbitals (NOs) are central constituents for evaluating correlation energies through efficient approximations. Here, we report the closed-form expression of the NOs of two-electron quantum rings, which are prototypical finite-extension systems and new starting points for the development of exchange-correlation functionals in density functional theory. We also show that the natural occupation numbers for these two-electron paradigms are in general non-vanishing and follow the same power law decay as atomic and molecular two-electron systems.

  10. Natural occupation numbers in two-electron quantum rings

    Energy Technology Data Exchange (ETDEWEB)

    Tognetti, Vincent, E-mail: vincent.tognetti@univ-rouen.fr [Normandy Univ., COBRA UMR 6014 & FR 3038, Université de Rouen, INSA Rouen, CNRS, 1 rue Tesniére, 76821 Mont Saint Aignan, Cedex (France); Loos, Pierre-François [Research School of Chemistry, Australian National University, Canberra ACT 2601 (Australia)

    2016-02-07

    Natural orbitals (NOs) are central constituents for evaluating correlation energies through efficient approximations. Here, we report the closed-form expression of the NOs of two-electron quantum rings, which are prototypical finite-extension systems and new starting points for the development of exchange-correlation functionals in density functional theory. We also show that the natural occupation numbers for these two-electron paradigms are in general non-vanishing and follow the same power law decay as atomic and molecular two-electron systems.

  11. Infinite occupation number basis of bosons: Solving a numerical challenge

    Science.gov (United States)

    Geißler, Andreas; Hofstetter, Walter

    2017-06-01

    In any bosonic lattice system, which is not dominated by local interactions and thus "frozen" in a Mott-type state, numerical methods have to cope with the infinite size of the corresponding Hilbert space even for finite lattice sizes. While it is common practice to restrict the local occupation number basis to Nc lowest occupied states, the presence of a finite condensate fraction requires the complete number basis for an exact representation of the many-body ground state. In this work we present a truncation scheme to account for contributions from higher number states. By simply adding a single coherent-tail state to this common truncation, we demonstrate increased numerical accuracy and the possible increase in numerical efficiency of this method for the Gutzwiller variational wave function and within dynamical mean-field theory.

  12. Statistical fluctuations of the number of neutrons in a pile

    International Nuclear Information System (INIS)

    Raievski, V.

    1958-01-01

    The theory of the statistical fluctuations in a pile is extended to the space dependent case, and gives the fluctuations of the number of neutrons in a cell of the core or reflector of the pile. This number changes through elementary processes occurring at random, which are, capture, source, fission and scattering. Of all these processes, fission is the only one which changes more than one neutron at a time and so is responsible of the deviation of the fluctuations from a Poisson law. The importance of this deviation depends on the dimensions of the cell compared to the slowing down length. When the dimensions are small, the fluctuations close to a Poisson law. (author) [fr

  13. Research on amplification multiple of source neutron number for ADS

    International Nuclear Information System (INIS)

    Liu Guisheng; Zhao Zhixiang; Zhang Baocheng; Shen Qingbiao; Ding Dazhao

    1998-01-01

    NJOY-91.91 and MILER code systems was applied to process and generate 44 group cross sections in AMPX master library format from CENDL-2 and ENDF/B-6. It is important an ADS (Accelerator-Driven System) assembly spectrum is used as the weighting spectrum for generating multi-group constants. Amplification multiples of source neutron number for several fast assemblies were calculated

  14. Study of the number of neutrons produced by fission of 239Pu

    International Nuclear Information System (INIS)

    Jacob, M.

    1958-01-01

    Study of the number of neutrons produced by fission of 239 Pu. The counting by coincidence of fissions and neutrons produced by these fissions allows the study of the variation of the mean number of neutrons emitted by ν fission. In the first chapter, it studied the variation of the mean number of neutrons emitted by 239 Pu fission with the energy of the incident neutron. A description of the experiment is given: a spectrometer with a crystal of sodium chloride or beryllium (mounted on a goniometer) is used, a fission chamber containing 10 mg of 239 Pu and the neutron detection system constituted of BF 3 counters which are enriched in 10 B. In the second part, the counting by coincidence of fissions and neutrons produced by the same fission and received by two different groups of counters allow the determination of a relationship between the root mean square and the average of neutron number produced by fission. The variation of the mean number of neutrons emitted by fission of 239 Pu is studied when we change from a thermal spectra of neutrons to a fission spectra of incident neutrons. Finally, when separating in two different part the fission chamber, it is possible to measure the mean number of neutrons emitted from fission of two different sources. It compared the mean number of neutrons emitted by fission of 239 Pu and 233 U. (M.P.)

  15. Benchmarking PARTISN with Analog Monte Carlo: Moments of the Neutron Number and the Cumulative Fission Number Probability Distributions

    Energy Technology Data Exchange (ETDEWEB)

    O' Rourke, Patrick Francis [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-10-27

    The purpose of this report is to provide the reader with an understanding of how a Monte Carlo neutron transport code was written, developed, and evolved to calculate the probability distribution functions (PDFs) and their moments for the neutron number at a final time as well as the cumulative fission number, along with introducing several basic Monte Carlo concepts.

  16. Disappearance of neutron magic numbers and deformation coexistence

    International Nuclear Information System (INIS)

    Kimura, Masaaki

    2014-01-01

    The disappearance of N=8, 20 and 28 magic numbers in the neutron excess nuclei is a representative example of the special features of the unstable nuclei. In this lecture of summer school, the problems of the magic number disappearance are presented. And the appearance of the deformation coexistence and the anomalous cluster structure come into the problem with them. At the begging the Antisymmetrized Molecular Dynamic (AMD) framework is explained with finite range two body central force and Gorgny DIS force composed of the zero range spin-orbit force and saturability. Island of inversion is explained in the nuclear chart shown in the figure and energy curves of the nuclei near 32 Mg and the excitation level schemes of 32 Mg are shown in the serial figures. As one of the extreme example of the nuclear structure the deformation of 19 F is picked up. The level schemes and structures of 21 F are shown as well. The molecule-like structure in the island of inversion is clear. The rotational band energy of fluorine isotopes are shown up to 29 F. As a new deformation area, disappearance of N=28 magic number is in the spotlight recently. In this case it is characteristic properties that the parities of the orbits to form the gap must be the same but the angular momenta should be different by 2. According to the AMD research, it is shown that deformations of prolate, three-axis asymmetric and oblate characters coexist in the very low excitation energy region accompanying the disappearance of N=28 gap. The concept of magic numbers has been very fundamental in nuclear physics since the success of shell model. At present its disappearance in the unstable nuclei is one of the most challenging problems in the understanding of the nuclear many body problems. (S. Funahashi)

  17. Critical fluctuations of the number of neutrons in a reactor

    International Nuclear Information System (INIS)

    Ryazanov, V.V.; Lakoza, E.L.; Sysoev, V.M.

    1995-01-01

    The nuclear chain reaction is the most important physical process in a reactor. The theory of nuclear chain reaction fluctuations (neutron noise), developed in and other studies, has given results that are important for reactor physics and reactor practice (correlation analysis of neutron noise for measurement of the physical characteristics and reactor monitoring, stability of the critical state, etc.). Here we propose to study these problems by applying the methods of continuous phase transitions and synergetics and using the analogy with chemical chain reactions and the general laws of critical phenomena. The optimal reactor operating conditions are critical. To predict how a critical reactor will behave it is necessary to reveal those features of the neutron laws that are universal in some way, i.e., do not depend on the details of the individual acts of neutron motion and transformation that occur in reactors of different types. The similarity between chemical and nuclear chain reactions was noted long ago. Consequently, a universal theory of continuous phase transition was developed for systems of diverse physical nature

  18. Statistical fluctuations of the number of neutrons in a pile; Fluctuations statistiques du nombre de neutrons dans une pile

    Energy Technology Data Exchange (ETDEWEB)

    Raievski, V [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    The theory of the statistical fluctuations in a pile is extended to the space dependent case, and gives the fluctuations of the number of neutrons in a cell of the core or reflector of the pile. This number changes through elementary processes occurring at random, which are, capture, source, fission and scattering. Of all these processes, fission is the only one which changes more than one neutron at a time and so is responsible of the deviation of the fluctuations from a Poisson law. The importance of this deviation depends on the dimensions of the cell compared to the slowing down length. When the dimensions are small, the fluctuations close to a Poisson law. (author) [French] La theorie des fluctuations statistiques est etendue au cas local et donne les fluctuations du nombre de neutrons dans une cellule situee dans le coeur ou le reflecteur de la pile. Ce nombre evolue au cours du temps sous l'influence de phenomenes aleatoires qui sont la capture, la diffusion, les sources et les neutrons secondaires de fission. L'emission simultanee de plusieurs neutrons distingue ce phenomene des precedents qui n'affectent qu'un neutron individuellement. L'importance de ce phenomene sur la loi de fluctuation depend des dimensions de la cellule par rapport a la longueur de ralentissement. Quand ces dimensions sont petites, le caractere particulier de ce phenomene disparait. (auteur)

  19. Study of the number of neutrons produced by fission of {sup 239}Pu; Etude du nombre de neutrons produits par la fission de {sup 239}Pu

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    Study of the number of neutrons produced by fission of {sup 239}Pu. The counting by coincidence of fissions and neutrons produced by these fissions allows the study of the variation of the mean number of neutrons emitted by {nu} fission. In the first chapter, it studied the variation of the mean number of neutrons emitted by {sup 239}Pu fission with the energy of the incident neutron. A description of the experiment is given: a spectrometer with a crystal of sodium chloride or beryllium (mounted on a goniometer) is used, a fission chamber containing 10 mg of {sup 239}Pu and the neutron detection system constituted of BF{sub 3} counters which are enriched in {sup 10}B. In the second part, the counting by coincidence of fissions and neutrons produced by the same fission and received by two different groups of counters allow the determination of a relationship between the root mean square and the average of neutron number produced by fission. The variation of the mean number of neutrons emitted by fission of {sup 239}Pu is studied when we change from a thermal spectra of neutrons to a fission spectra of incident neutrons. Finally, when separating in two different part the fission chamber, it is possible to measure the mean number of neutrons emitted from fission of two different sources. It compared the mean number of neutrons emitted by fission of {sup 239}Pu and {sup 233}U. (M.P.)

  20. Determination of selected metals in the body tissues of occupationally exposed stainless steel workers by neutron activation analysis

    International Nuclear Information System (INIS)

    Kucera, J.; Soukal, L.; Randa, Z.; Borska, L.; Bencko, V.; Tejral, J.

    2002-01-01

    Occupational exposure was examined in a group of 20 workers dealing mainly with welding, polishing, and assembling of stainless steel constructions. Biological monitoring of exposure involved the determination of Cr, Mn, Mo, Ni and V in hair and nails by instrumental neutron activation analysis (INAA), urinary Cr and Mn, serum Cr and blood Mn by neutron activation analysis with radiochemical separation (RNAA). The RNAA procedures employed are briefly described. Significantly elevated levels were found for Cr in hair, nails, serum and urine, Mo in hair, and Mn in blood in the exposed subjects compared to controls. The ratios of the mean elemental concentrations for the exposed/control subjects were as follows: 12.5 for hair Cr, 4.4 for nail Cr, 9.6 for serum Cr, 9.0 for urinary Cr, 1.4 for hair Mo and 1.3 for blood Mn. For quality control purposes a number of biological intercomparison and reference materials were analysed. A good agreement obtained with consensus and/or certified values proved the accuracy of our results. The results for the control group compared also well with reference values, thus indicating that no contamination occurred on sampling and sample treatment prior to irradiation. To be able to evaluate the health effects of exposure, haematological, genotoxicity and immunological parameters were also assayed. A number of immunological parameters were altered in the exposed group compared to controls. However, no significant correlations were found between exposure of the individual workers measured with the aid of personal air particulate samplers and the biological indicators of exposure. A comparison of direct and biological monitoring indicates the complexity of the assessment of health effects of occupational exposure. (author)

  1. 4π-spectrometer technique for measurements of secondary neutron average number in nuclear fission by 252Cf neutrons

    International Nuclear Information System (INIS)

    Vasil'ev, Yu.A.; Barashkov, Yu.A.; Golovanov, O.A.; Sidorov, L.V.

    1977-01-01

    A method for determining the average number of secondary neutrons anti ν produced in nuclear fission by the neutrons of the 252 Cf fission spectra by means of a 4π time-of-flight spectrometer is described. Layers of 252 Cf and an isotope studied are placed close to each other; if the isotope layer density is 1 mg/cm 2 probability of its fission is about 10 -5 per one spontaneous fission of californium. Fission fragments of 252 Cf and the isotope investigated have been detected by two surface-barrier counters with an efficiency close to 100%. The layers and the counters are situated in a measuring chamber placed in the center of the 4π time-of-flight spectrometer. The latter is utilized as a neutron counter because of its fast response. The method has been verified by carrying out measurements for 235 U and 239 Pu. A comparison of the experimental and calculated results shows that the method suggested can apply to determine the number of secondary neutrons in fission of isotopes that have not been investigated yet

  2. Determination of mercury in urine through Neutron activation analysis in dentists, as a measure of occupational exposure

    International Nuclear Information System (INIS)

    Padilla M, M.A.

    2000-01-01

    The mercury level was studied in urine to a dentists group belonging at the Universidad Autonoma del Estado de Mexico to determine the grade of contamination to the exposure of this element during their occupational activity. It was used the Neutron activation analysis which is an analytical method based in the irradiation with neutrons toward a stable nuclide. This can suffer a nuclear transformation to produce a radioactive nuclide and so it will be able to realize a quantitative analysis of itself. The TRIGA Mark III Reactor at the Nuclear Center in Mexico was used to realize this type of analysis due to the neutron fluxes which can be obtained as well as to the facilities in the irradiation of the sample.The purpose of this work is to determine the concentrations of mercury in the occupational exposed personnel such as dentists and so giving the recommendations of safety required to their production. (Author)

  3. Distribution of occupation numbers in finite Fermi systems and role of interaction in chaos and thermalization

    International Nuclear Information System (INIS)

    Flambaum, V.V.; Izrailev, F.M.

    1997-01-01

    A method is developed for calculation of single-particle occupation numbers in finite Fermi systems of interacting particles. It is more accurate than the canonical distribution method and gives the Fermi-Dirac distribution in the limit of large number of particles. It is shown that statistical effects of the interaction are absorbed by an increase of the effective temperature. Criteria for quantum chaos and statistical equilibrium are considered. All results are confirmed by numerical experiments in the two-body random interaction model. copyright 1997 The American Physical Society

  4. Particle-number fluctuations and neutron-proton pairing effects on proton and neutron radii of even-even N Almost-Equal-To Z nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Douici, M.; Allal, N. H.; Fellah, M.; Benhamouda, N.; Oudih, M. R. [Laboratoire de Physique Theorique, Faculte de Physique, USTHB BP 32 El-Alia, 16111 Bab-Ezzouar, Alger (Algeria) and Institut des Sciences et Technologie, Centre Universitaire de Khemis Miliana, Route de Theniet-El-Had, 44225 Khemis-Milia (Algeria); Laboratoire de Physique Theorique, Faculte de Physique, USTHB BP 32 El-Alia, 16111 Bab-Ezzouar, Alger (Algeria) and Centre de Recherche Nucleaire d' Alger, COMENA, BP399 Alger-Gare, Alger (Algeria); Laboratoire de Physique Theorique, Faculte de Physique, USTHB BP 32 El-Alia, 16111 Bab-Ezzouar, Alger (Algeria)

    2012-10-20

    The particle-number fluctuation effect on the root-mean-square (rms) proton and neutron radii of even-even N Almost-Equal-To Z nuclei is studied in the isovector neutron-proton (np) pairing case using an exact particle-number projection method and the Woods-Saxon model.

  5. Constraining neutron-star tidal Love numbers with gravitational-wave detectors

    International Nuclear Information System (INIS)

    Flanagan, Eanna E.; Hinderer, Tanja

    2008-01-01

    Ground-based gravitational wave detectors may be able to constrain the nuclear equation of state using the early, low frequency portion of the signal of detected neutron star-neutron star inspirals. In this early adiabatic regime, the influence of a neutron star's internal structure on the phase of the waveform depends only on a single parameter λ of the star related to its tidal Love number, namely, the ratio of the induced quadrupole moment to the perturbing tidal gravitational field. We analyze the information obtainable from gravitational wave frequencies smaller than a cutoff frequency of 400 Hz, where corrections to the internal-structure signal are less than 10%. For an inspiral of two nonspinning 1.4M · neutron stars at a distance of 50 Megaparsecs, LIGO II detectors will be able to constrain λ to λ≤2.0x10 37 g cm 2 s 2 with 90% confidence. Fully relativistic stellar models show that the corresponding constraint on radius R for 1.4M · neutron stars would be R≤13.6 km (15.3 km) for a n=0.5 (n=1.0) polytrope with equation of state p∝ρ 1+1/n

  6. Statistical physics as an approximate method of many-body quantum mechanics in the representation of occupation numbers

    International Nuclear Information System (INIS)

    Kushnirenko, A.N.

    1989-01-01

    An attempt was made to substantiate statistical physics from the viewpoint of many-body quantum mechanics in the representation of occupation numbers. This approach enabled to develop the variation method for solution of stationary and nonstationary nonequilibrium problems

  7. Pennsylvania Occupational Competency Assessment Program--1983. Final Report. Vocational-Technical Education Research Report, Volume 22, Number 2. Occupational Competency Evaluation Monograph, Number 15.

    Science.gov (United States)

    Walter, Richard A.

    The Pennsylvania State University served as the Pennsylvania Coordinator of Occupational Competency Assessment (OCA). It managed the Pennsylvania OCA Program, which provides the secondary public schools of the state with competent vocational instructors as a component of teacher preparation at Temple University, Indiana University of Pennsylvania,…

  8. Tidal Love numbers of neutron and self-bound quark stars

    International Nuclear Information System (INIS)

    Postnikov, Sergey; Prakash, Madappa; Lattimer, James M.

    2010-01-01

    Gravitational waves from the final stages of inspiraling binary neutron stars are expected to be one of the most important sources for ground-based gravitational wave detectors. The masses of the components are determinable from the orbital and chirp frequencies during the early part of the evolution, and large finite-size (tidal) effects are measurable toward the end of inspiral, but the gravitational wave signal is expected to be very complex at this time. Tidal effects during the early part of the evolution will form a very small correction, but during this phase the signal is relatively clean. The accumulated phase shift due to tidal corrections is characterized by a single quantity related to a star's tidal Love number. The Love number is sensitive, in particular, to the compactness parameter M/R and the star's internal structure, and its determination could provide an important constraint to the neutron star radius. We show that Love numbers of self-bound strange quark matter stars are qualitatively different from those of normal neutron stars. Observations of the tidal signature from coalescing compact binaries could therefore provide an important, and possibly unique, way to distinguish self-bound strange quark stars from normal neutron stars. Tidal signatures from self-bound strange quark stars with masses smaller than 1M · are substantially smaller than those of normal stars owing to their smaller radii. Thus tidal signatures of stars less massive than 1M · are probably not detectable with Advanced LIGO. For stars with masses in the range 1-2M · , the anticipated efficiency of the proposed Einstein telescope would be required for the detection of tidal signatures.

  9. Influence of the number of energy groups on the accuracy of neutron fluence calculations

    International Nuclear Information System (INIS)

    Barz, H.U.; Konheiser, J.

    1999-01-01

    The question how many groups are necessary to obtain all needed integral quantities for the neutron load of pressure vessels and detector positions outside the vessel with sufficient accuracy is of general interest. Until now, there are no systematic investigations on this question. In principle 3-dimensional consideration is required for such neutron load calculations. Therefore, an estimation of the needed number of groups can be of interest to minimize calculation time. One general problem is the P L -approximation of the angular distributions for the transfers between different groups. For elastic scattering this P L -approximation becomes poorer with increasing number of groups. As deterministic methods generally use the P L -approximation they cannot be used for investigations of the errors caused by the group approximation. We have investigated this problem applying group Monte-Carlo but nearly exact representation of this elastic slowing down without P L -approximation. The calculations were directed to assess the neutron fluence of a Russian WWER-1000 reactor. For that a simplified geometrical model of this reactor type has been used. (orig.)

  10. Imbalances in the German public health system - numbers of state-certified occupational physicians and relation to socioeconomic data.

    Science.gov (United States)

    Gyo, Christoph; Boll, Michael; Brüggmann, Dörthe; Klingelhöfer, Doris; Quarcoo, David; Groneberg, David A

    2016-01-01

    State-certified occupational physicians who work as civil servants in the Federal Republic of Germany are key players in the German Public Health system. They control i.e. the legal compliance in occupational health and participate in the occupational disease procedures. Despite the role model function of the German Public health system for many developing countries, this area of Public health is debated to have been hampered in the past years by a disregard concerning structural developments. Different databases were screened for occupational health benchmarks. Obtained data were compared to socioeconomic data and indices were calculated. The overall numbers of State-certified occupational physicians decreased in Germany between 1992 and 2012 from 136 to 86 (63 %). On the single state level, the ratios of State-certified occupational physicians per 1 Mio. working population ranged from 8 for the state of Saarland to 0.8 for the state of North Rhine Westphalia. A general difference was found for old versus new German states. Also, large differences were present for the ratios of State-certified occupational physicians per 10 6 employees towards public debt per capita (€) and the ratios of State-certified occupational physicians per Gross Domestic Product (GDP) in the 16 German states in 2012. In striking contrast to the WHO document on the Occupational safety and health (OSH) system that states in its executive summary that the human and institutional capacities of the German occupational health system are very strong in both quantity and quality, we here show extreme imbalances present at the single state levels that developed over the past 20 years. With a regard to the increasing complexity of the economic system a reversal of this trend should be demanded.

  11. Mass number dependence of total neutron cross section; a discussion based on the semi-classical optical model

    International Nuclear Information System (INIS)

    Angeli, Istvan

    1990-01-01

    The dependence of total neutron cross section on mass number can be calculated by the black nucleus formula, according to the optical model. The fine structure of mass number dependence is studied, and a correction factor formula is given on the basis of a semi-classical optical model. Yielding results in good agreement with experimental data. In addition to the mass number dependence, the neutron-energy dependence can also be calculated using this model. (K.A.)

  12. Number distribution of leakage neutrons for single neutron emission event and one source emission event in multiplying medium for two variables - a GEANT4 study

    International Nuclear Information System (INIS)

    Roy, Arup Singha; Raman, Anand; Chaudhury, Probal; Thomas, Renju G.

    2018-01-01

    A quantitative knowledge about the neutron multiplying character of a neutron multiplying medium such as High enriched Uranium (HEU), Weapon Graded plutonium (WGPu) and similar special nuclear materials is essential for improving the probability of detection of these materials to check against illicit trafficking. The objective of this study is to gain a deeper insight in to the neutron and gamma multiplication behaviour of these materials. The leakage number distribution of neutron and gamma initiated by a source emission event (Spontaneous Fission) as well as single neutron emission event has been obtained in the course of this study. The computations for this study were carried out through GEANT4 simulation and also with the help of FREYA incorporated into it. This helped to carry out a detailed analysis of each history more realistically and obtain more reliable results

  13. Time-dependent occupation numbers in reduced-density-matrix-functional theory: Application to an interacting Landau-Zener model

    International Nuclear Information System (INIS)

    Requist, Ryan; Pankratov, Oleg

    2011-01-01

    We prove that if the two-body terms in the equation of motion for the one-body reduced density matrix are approximated by ground-state functionals, the eigenvalues of the one-body reduced density matrix (occupation numbers) remain constant in time. This deficiency is related to the inability of such an approximation to account for relative phases in the two-body reduced density matrix. We derive an exact differential equation giving the functional dependence of these phases in an interacting Landau-Zener model and study their behavior in short- and long-time regimes. The phases undergo resonances whenever the occupation numbers approach the boundaries of the interval [0,1]. In the long-time regime, the occupation numbers display correlation-induced oscillations and the memory dependence of the functionals assumes a simple form.

  14. ENTROPY PRODUCTION IN COLLISIONLESS SYSTEMS. II. ARBITRARY PHASE-SPACE OCCUPATION NUMBERS

    International Nuclear Information System (INIS)

    Barnes, Eric I.; Williams, Liliya L. R.

    2012-01-01

    We present an analysis of two thermodynamic techniques for determining equilibria of self-gravitating systems. One is the Lynden-Bell (LB) entropy maximization analysis that introduced violent relaxation. Since we do not use the Stirling approximation, which is invalid at small occupation numbers, our systems have finite mass, unlike LB's isothermal spheres. (Instead of Stirling, we utilize a very accurate smooth approximation for ln x!.) The second analysis extends entropy production extremization to self-gravitating systems, also without the use of the Stirling approximation. In addition to the LB statistical family characterized by the exclusion principle in phase space, and designed to treat collisionless systems, we also apply the two approaches to the Maxwell-Boltzmann (MB) families, which have no exclusion principle and hence represent collisional systems. We implicitly assume that all of the phase space is equally accessible. We derive entropy production expressions for both families and give the extremum conditions for entropy production. Surprisingly, our analysis indicates that extremizing entropy production rate results in systems that have maximum entropy, in both LB and MB statistics. In other words, both thermodynamic approaches lead to the same equilibrium structures.

  15. Neutron scattering for the analysis of biological structures. Brookhaven symposia in biology. Number 27

    Energy Technology Data Exchange (ETDEWEB)

    Schoenborn, B P [ed.

    1976-01-01

    Sessions were included on neutron scattering and biological structure analysis, protein crystallography, neutron scattering from oriented systems, solution scattering, preparation of deuterated specimens, inelastic scattering, data analysis, experimental techniques, and instrumentation. Separate entries were made for the individual papers.

  16. Evidence for prevalent Z = 6 magic number in neutron-rich carbon isotopes.

    Science.gov (United States)

    Tran, D T; Ong, H J; Hagen, G; Morris, T D; Aoi, N; Suzuki, T; Kanada-En'yo, Y; Geng, L S; Terashima, S; Tanihata, I; Nguyen, T T; Ayyad, Y; Chan, P Y; Fukuda, M; Geissel, H; Harakeh, M N; Hashimoto, T; Hoang, T H; Ideguchi, E; Inoue, A; Jansen, G R; Kanungo, R; Kawabata, T; Khiem, L H; Lin, W P; Matsuta, K; Mihara, M; Momota, S; Nagae, D; Nguyen, N D; Nishimura, D; Otsuka, T; Ozawa, A; Ren, P P; Sakaguchi, H; Scheidenberger, C; Tanaka, J; Takechi, M; Wada, R; Yamamoto, T

    2018-04-23

    The nuclear shell structure, which originates in the nearly independent motion of nucleons in an average potential, provides an important guide for our understanding of nuclear structure and the underlying nuclear forces. Its most remarkable fingerprint is the existence of the so-called magic numbers of protons and neutrons associated with extra stability. Although the introduction of a phenomenological spin-orbit (SO) coupling force in 1949 helped in explaining the magic numbers, its origins are still open questions. Here, we present experimental evidence for the smallest SO-originated magic number (subshell closure) at the proton number six in 13-20 C obtained from systematic analysis of point-proton distribution radii, electromagnetic transition rates and atomic masses of light nuclei. Performing ab initio calculations on 14,15 C, we show that the observed proton distribution radii and subshell closure can be explained by the state-of-the-art nuclear theory with chiral nucleon-nucleon and three-nucleon forces, which are rooted in the quantum chromodynamics.

  17. Time to reach a given level of number of neutrons is stochastic analog of reactor period

    International Nuclear Information System (INIS)

    Ryazanov, V.V.

    2012-01-01

    In theory and in practice the operation of nuclear reactors to control the safety of the reactor is widely used deterministic value - the period of the reactor. It is proposed along with the period of the reactor using a stochastic analogue of this magnitude - a random amount of time to achieve a given level of a random process for the number of neutrons in the reactor. The paper discusses various features of the behavior of the mean and variance of time to achieve a specified level. This kind of features can be associated with impaired behavior of the reactor system. Introduced the value of time required to reach the level can be used to monitor and improve the safety of nuclear power plants

  18. GAMSOURCE - WRS system module number 38474 for calculating gamma-ray sources produced by neutron capture

    International Nuclear Information System (INIS)

    Grimstone, M.J.

    1978-06-01

    The WRS Modular Programming System has been developed as a means by which programmes may be more efficiently constructed, maintained and modified. In this system a module is a self-contained unit typically composed of one or more Fortran routines, and a programme is constructed from a number of such modules. This report describes one WRS module, the function of which is to calculate the source strength of gamma-rays arising from neutron capture in a system represented in one-dimensional geometry. The information given in this manual is of use both to the programmer wishing to incorporate the module in a programme, and to the user of such a programme. (author)

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

    Czech Academy of Sciences Publication Activity Database

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

    2004-01-01

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

  20. BUSINESS PROCEDURES. AGRICULTURAL SUPPLY - SALES AND SERVICE OCCUPATIONS, MODULE NUMBER 6.

    Science.gov (United States)

    Ohio State Univ., Columbus. Center for Vocational and Technical Education.

    THE PURPOSE OF THIS MODULE, ONE OF A SERIES DEVELOPED TO ASSIST TEACHERS TO TRAIN HIGH SCHOOL STUDENTS FOR AGRICULTURAL SUPPLY OCCUPATIONS, IS TO DEVELOP ABILITY TO USE COMMON AGRICULTURAL BUSINESS PROCEDURES. IT WAS DEVELOPED BY A NATIONAL TASK FORCE ON THE BASIS OF DATA FROM STATE STUDIES. SECTIONS ARE (1) RECORDS IN BUSINESS, (2) SALES TICKETS…

  1. DIESEL ENGINE SYSTEMS. AGRICULTURAL MACHINERY--SERVICE OCCUPATIONS, MODULE NUMBER 15.

    Science.gov (United States)

    Ohio State Univ., Columbus. Center for Vocational and Technical Education.

    ONE OF A SERIES DESIGNED TO HELP TEACHERS PREPARE POSTSECONDARY STUDENTS FOR AGRICULTURAL MACHINERY SERVICE OCCUPATIONS AS PARTS MEN, MECHANICS, MECHANIC'S HELPERS, AND SERVICE SUPERVISORS, THIS GUIDE AIMS TO DEVELOP STUDENT UNDERSTANDING OF THE CONSTRUCTION AND OPERATING PRINCIPLES OF DIESEL ENGINES. IT WAS DEVELOPED BY A NATIONAL TASK FORCE ON…

  2. Risk horoscopes: Predicting the number and type of serious occupational accidents in The Netherlands for sectors and jobs

    International Nuclear Information System (INIS)

    Bellamy, Linda J.; Damen, Martin; Jan Manuel, Henk; Aneziris, Olga N.; Papazoglou, Ioannis A.; Oh, Joy I.H.

    2015-01-01

    The risk of a serious occupational accident per hour exposure was calculated in a project to develop an occupational risk model in the Netherlands (WebORCA). To obtain risk rates, the numbers of victims of serious occupational accidents investigated by the Dutch Labour inspectorate 1998–Feb 2004 were divided by the number of hours exposure for each of 64 different types of hazards, such as contact with moving parts of machines and falls from various types of height. The exposures to the occupational accident hazards were calculated from a survey of a panel of 30,000 from the Dutch working population. Sixty risk rates were then used to predict serious accidents for activity sectors and jobs in the Netherlands where exposures to the hazards for sectors or jobs could be estimated from the survey. Such predictions have been called “horoscopes” because the idea is to provide a quick look-up of predicted accidents for a particular sector or job. Predictions compared favourably with actual data. It is concluded that predictive data can help provide information about accidents in cases where there is a lack of data, such as for smaller sub groups of the working population. - Highlights: • Dutch occupational accident risk rates and yearly exposures for 60 hazards are given. • Risks rates are based on the 1% most serious accidents 1998–Feb 2004. • Risk rates are used to predict serious accident risks in jobs and sectors. • Predictions (“risk horoscopes”) give a good match with actual accidents. • Risk horoscopes can help worker groups identify most important accident risks

  3. The number of degrees of freedom for statistical distribution of s wave reduced neutron width for several nuclei

    International Nuclear Information System (INIS)

    Zhixiang, Z.

    1983-01-01

    The least squares fit has been performed using chi-squared distribution function for all available evaluated data for s-wave reduced neutron width of several nuclei. The number of degrees of freedom and average value have been obtained. The missing levels of weak s-wave resonances and extra p-wave levels have been taken into account, if any. For 75 As and 103 Rh, s-wave population has been separated by Bayes' theorem before making fit. The results thus obtained are consistent with Porter-Thomas distribution, i.e., chi-squared distribution with γ=1, as one would expect. It has not been found in this work that the number of degrees of freedom for the distribution of s-wave reduced neutron width might be greater than one as reported by H.C.Sharma et al. (1976) at the international conference on interactions of neutrons with nuclei. (Auth.)

  4. Study of occupational health impact of atmospheric pollution on exposed workers at an iron and steel complex by using neutron activation analysis of scalp hair

    International Nuclear Information System (INIS)

    Chai, Z.F.; Qian, Q.F.; Feng, X.Q.; Zhang, P.Q.; Liu, N.Q.; Feng, W.Y.

    2004-01-01

    The occupational health impact of atmospheric pollution on exposed workers at one iron and steel complex was studied by instrumental neutron activation analysis of workers' hair samples and medical examination. The experimental results indicate that there is a positive correlation between the high inhalation amounts of iron and other trace elements by the exposed workers and the symptom of their high blood pressure and hypoglycemia, which implies that the atmospheric environment polluted by iron and steel industry has an adverse health impact on the exposed workers. The measures to relieve and abate the occupational diseases caused by air-borne particulate matter should be taken. (author)

  5. Band crossings in mercury nuclei: effect of occupation of i13/2 neutron orbits

    International Nuclear Information System (INIS)

    Khadkikar, S.B.; Praharaj, C.R.

    1984-04-01

    The K=0 + ground band and two rotation-aligned bands (K=1 + or K2 + two quasi-particle band and K=2 + four quasi-particle band) are studied in 198 Hg, 194 Hg and 190 Hg by angular momentum projection from Hartree-Fock and particle-hole intrinsic states. There is a first anomaly in these three nuclei around 8(h/2π) due to the crossing of the ground band and the two quasi-particle band. Because of the nature of occupation of i13/2 orbitals the four quasi-particle band is too highlying in 198 Hg and does not cross the two quasi-particle bands, while such a second crossing occurs in 194 Hg and 190 Hg near 20 (h/2π). (author)

  6. Neutron spectrometry and dosimetry with neural networks and Bonner spheres: a study to reduce the spheres number

    International Nuclear Information System (INIS)

    Espinoza G, J. G.; Martinez B, M. R.; Leon P, A. A.; Hernandez P, C. F.; Castaneda M, V. H.; Solis S, L. O.; Castaneda M, R.; Ortiz R, J. M.; Vega C, H. R.; Mendez, R.; Gallego, E.; De Sousa L, M. A.

    2016-10-01

    For neutron spectrometry and neutron dosimetry, the Bonner spheres spectrometric system has been the most widely used system, however, the number, size and weight of the spheres composing the system, as well as the need to use a reconstruction code and the long periods of time used to carry out the measurements are some of the disadvantages of this system. For the reconstruction of the spectra, different techniques such as artificial neural networks of reverse propagation have been used. The objective of this work was to reduce the number of Bonner spheres and to use counting speeds in a reverse propagation neural network, optimized by means of the robust design methodology, to reconstruct the neutron spectra. For the design of the neural network we used the neutron spectra of the IAEA and the response matrix of the Bonner spheres with "6LiI(Eu) detector. The performance of the network was compared; using 7 Bonner spheres against other cases where only 2 and one sphere are used. The network topologies were trained 36 times for each case keeping constant the objective error (1E(-3)), the training algorithm was trains cg and the robust design methodology to determine the best network architectures. With these, the best and worst results were compared. The results obtained using 7 spheres were similar to those with the 5-in sphere, however is still in an information analysis stage. (Author)

  7. Time dependent and asymptotic neutron number probability distribution calculation using discrete Fourier transform

    International Nuclear Information System (INIS)

    Humbert, Ph.

    2005-01-01

    In this paper we consider the probability distribution of neutrons in a multiplying assembly. The problem is studied using a space independent one group neutron point reactor model without delayed neutrons. We recall the generating function methodology and analytical results obtained by G.I. Bell when the c 2 approximation is used and we present numerical solutions in the general case, without this approximation. The neutron source induced distribution is calculated using the single initial neutron distribution which satisfies a master (Kolmogorov backward) equation. This equation is solved using the generating function method. The generating function satisfies a differential equation and the probability distribution is derived by inversion of the generating function. Numerical results are obtained using the same methodology where the generating function is the Fourier transform of the probability distribution. Discrete Fourier transforms are used to calculate the discrete time dependent distributions and continuous Fourier transforms are used to calculate the asymptotic continuous probability distributions. Numerical applications are presented to illustrate the method. (author)

  8. Son preference, number of children, education and occupational choice in rural Nepal

    OpenAIRE

    Hatlebakk, Magnus

    2012-01-01

    A unique family survey was conducted in Nepal to investigate the economic consequences of having a first-born girl. Women get more children, but we find no causal effect of number of children on economic outcomes. But independently of the number of children there is a positive effect on boys' education of having a first born sister, who presumably takes care of household work so the boys can focus on school. This indicates a stronger son-preference in Nepal than what is found in studies from ...

  9. Neutron occupancy of the 0d{sub 5/2} orbital and the N=16 shell closure in {sup 24}O

    Energy Technology Data Exchange (ETDEWEB)

    Tshoo, K., E-mail: tshoo@ibs.re.kr [Rare Isotope Science Project, Institute for Basic Science, Daejeon 305-811 (Korea, Republic of); Satou, Y. [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Bertulani, C.A. [Texas A and M University-Commerce, PO Box 3011, Commerce, Texas 75429 (United States); Bhang, H.; Choi, S. [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Nakamura, T.; Kondo, Y.; Deguchi, S.; Kawada, Y.; Nakayama, Y.; Tanaka, K.N.; Tanaka, N.; Togano, Y. [Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551 (Japan); Kobayashi, N. [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan); Aoi, N. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan); Ishihara, M.; Motobayashi, T.; Otsu, H.; Sakurai, H.; Takeuchi, S. [RIKEN Nishina Center, Saitama 351-0198 (Japan); and others

    2014-12-12

    One-neutron knockout from {sup 24}O leading to the first excited state in {sup 23}O has been measured for a proton target at a beam energy of 62 MeV/nucleon. The decay energy spectrum of the neutron unbound state of {sup 23}O was reconstructed from the measured four momenta of the {sup 22}O fragment and emitted neutron. A sharp peak was found at E{sub decay}=50±3 keV, corresponding to an excited state in {sup 23}O at 2.78±0.11 MeV, as observed in previous measurements. The longitudinal momentum distribution for this state was consistent with d-wave neutron knockout, providing support for a J{sup π} assignment of 5/2{sup +}. The associated spectroscopic factor was deduced to be C{sup 2}S(0d{sub 5/2})=4.1±0.4 by comparing the measured cross section (σ{sub −1n}{sup exp}=61±6 mb) with a distorted wave impulse approximation calculation. Such a large occupancy for the neutron 0d{sub 5/2} orbital is in line with the N=16 shell closure in {sup 24}O.

  10. Effect of fast neutrons and gamma rays treatments on heading date, plant height and tiller number in wheat

    International Nuclear Information System (INIS)

    Arain, M.A.

    1978-01-01

    Homogeneous seeds of six varieties of bread wheat, Triticum aestivum L. (2n = 6x = 42) were treated with fast neutrons and gamma rays. The irradiated seeds along with respective controls were grown in field plots during 1973-74 and heating date, plant height and tiller number studied. Varieties used in the present study varied significantly (P >=0.01) for all the characters. Treatment mean squares were highly significant for plant height and tillers per plant; whereas, the varieties x treatments interaction mean squares were significant only for plant height (P >= 0.05). Irradiated treatments exhibited significant reductions in plant height and tiller number than respective controls. However, heading was delayed among the irradiated material when compared with respective controls. Reduction in plant height was more pronounced after the treatments of gamma rays than the fast neutrons. The maximum and minimum shifts in mean values of these characters were observed in 20 kR (gamma rays) and Nf 300 RADS (fast neutrons) treatments, respectively. (author)

  11. The total workload of male and female white collar workers as related to age, occupational level, and number of children.

    Science.gov (United States)

    Lundberg, U; Mårdberg, B; Frankenhaeuser, M

    1994-12-01

    A questionnaire assessing various aspects of paid as well as unpaid forms of productive activity was mailed to stratified samples of male and female white collar workers, approximately matched for educational and occupational level. Data from 501 men and 679 women employed full time revealed traditional gender differences in terms of main responsibility for household duties, child care etc. In keeping with this, women reported higher levels of work overload, stress and conflict than men, which increased significantly with the number of children at home. The various stress indices reached a peak between the ages of 35 and 39. Men reported more autonomy in their paid work whereas women reported more control at home. Men and women at the upper managerial levels reported more control over their total work situation and less conflict between demands.

  12. Moment of inertia, quadrupole moment, Love number of neutron star and their relations with strange-matter equations of state

    Science.gov (United States)

    Bandyopadhyay, Debades; Bhat, Sajad A.; Char, Prasanta; Chatterjee, Debarati

    2018-02-01

    We investigate the impact of strange-matter equations of state involving Λ hyperons, Bose-Einstein condensate of K- mesons and first-order hadron-quark phase transition on moment of inertia, quadrupole moment and tidal deformability parameter of slowly rotating neutron stars. All these equations of state are compatible with the 2 M_{solar} constraint. The main findings of this investigation are the universality of the I- Q and I -Love number relations, which are preserved by the EoSs including Λ hyperons and antikaon condensates, but broken in the presence of a first-order hadron-quark phase transition. Furthermore, it is also noted that the quadrupole moment approaches the Kerr value of a black hole for maximum-mass neutron stars.

  13. Determination of the average number of neutrons per fission event for californium-252

    International Nuclear Information System (INIS)

    Aleksandrov, B.M.; Belov, L.M.; Drapchinskij, L.V.

    1982-01-01

    By means of a separate determination of neutron yields and fission event rates, the value of #betta#-bar( 252 Cf) has been measured for a series of new high-purity sources. The improved quality of the source active layers has reduced the error in determining the fission rate to 0.35%. The value obtained for #betta#-bar( 252 Cf) is 3.747+-0.036. A description is given of the design and the parameters of a spherical manganese bath in which the work on refining the value of #betta#-bar( 252 Cf) will be continued. (author)

  14. Inelastic neutron scattering study on the polytypism of even-numbered n-alkanes

    Science.gov (United States)

    Kubota, Hideki; Kaneko, Fumitoshi; Kawaguchi, Tatsuya

    2005-02-01

    The thermodynamic properties of the two polytypes of n-hexatriacontane ( n- C36H74), single-layered structure Mon and double-layered structure Orth II, have been studied with incoherent inelastic neutron scattering and solubility measurements. The solubility measurements show that Orth II is more stable than Mon, because of its larger entropy. The neutron scattering measurements reveal that the vibrational modes of Orth II shift to the lower frequencies compared with those of Mon in the frequency region below 120 cm-1. The vibrational modes in this region make a dominant contribution to the vibrational entropy of a system, and the advantage of Orth II in vibrational entropy due to the low-frequency shifts is estimated to be 7.8 J K-1 mol-1 at 288 K under the harmonic approximation, which is in good agreement with the entropy difference between Mon and Orth II determined by solubility measurements. These results suggest that the relative stability of polytypic structures of long-chain compounds is mainly determined by the vibrational entropy of the low-frequency modes.

  15. Assessment of the critical neutron number for internal break-even in explosion-induced thermonuclear fusion

    International Nuclear Information System (INIS)

    Kaliski, S.

    1979-01-01

    An analysis is performed of the systems of an explosion-induced thermonuclear microfusion from the angle of attaining an internal break-even. A critical-state meter is defined, i.e. the critical neutron yield Nsub(cr) as the most convenient for characterizing the experimental setups. It is demonstrated that in a number of designed systems of an explosion-induced microfusion, Nsub(cr) is attained. In the experiments actually carried out the N-yield efficiency is of about three orders of magnitude. (author)

  16. A LIMIT ON THE NUMBER OF ISOLATED NEUTRON STARS DETECTED IN THE ROSAT ALL-SKY-SURVEY BRIGHT SOURCE CATALOG

    International Nuclear Information System (INIS)

    Turner, Monica L.; Rutledge, Robert E.; Letcavage, Ryan; Shevchuk, Andrew S. H.; Fox, Derek B.

    2010-01-01

    Using new and archival observations made with the Swift satellite and other facilities, we examine 147 X-ray sources selected from the ROSAT All-Sky-Survey Bright Source Catalog (RASS/BSC) to produce a new limit on the number of isolated neutron stars (INSs) in the RASS/BSC, the most constraining such limit to date. Independent of X-ray spectrum and variability, the number of INSs is ≤48 (90% confidence). Restricting attention to soft (kT eff < 200 eV), non-variable X-ray sources-as in a previous study-yields an all-sky limit of ≤31 INSs. In the course of our analysis, we identify five new high-quality INS candidates for targeted follow-up observations. A future all-sky X-ray survey with eROSITA, or another mission with similar capabilities, can be expected to increase the detected population of X-ray-discovered INSs from the 8-50 in the BSC, to (for a disk population) 240-1500, which will enable a more detailed study of neutron star population models.

  17. Neutron radiography with ultracold neutrons

    International Nuclear Information System (INIS)

    Bates, J.C.

    1981-01-01

    The neutron transmission factor of very thin films may be low if the neutron energy is comparable to the pseudo-potential of the film material. Surprisingly, perhaps, it is relatively easy to obtain neutrons with such low energies in sufficient numbers to produce neutron radiographs. (orig.)

  18. Calculation of the distribution of the escaping from a fissionable sample neutrons number when introducing one fission neutron in that sample

    International Nuclear Information System (INIS)

    Dorlet, J.

    1991-01-01

    A describing algorithm furnishes the probabilities of having exactly N escaping neutrons in the descent of one fission neutron, using the punctual reactor model. Calculations can be performed even for N-values greater than 1000. Numerical results show that discrete neutrons counting is unfit to obtain the N mean value, even for very far subcritical devices. That mean value is still very used in the existing theoretical studies, because its obvious correlation with the device effective multiplication coefficient. For that reason modelling coincidence neutrons counting is not suitable using statistical moments approach, but only using probabilities it selves [fr

  19. Optimization of the architecture of a neural network in neutron spectrometry to reduce the number of Bonner spheres

    International Nuclear Information System (INIS)

    Leon P, A. A.; Martinez B, M. R.; Hernandez P, C. F.; Espinoza G, J. G.; Castaneda M, V. H.; Solis S, L. O.; Castaneda M, R.; Ortiz R, J. M.; Vega C, H. R.; Mendez V, R.; Gallego, E.; De Sousa L, M. A.

    2016-10-01

    The neutron spectrometry is an experimental process for determining the energy distribution called the Spectrum. Among the methods available for neutron spectrometry, one can mention the Bonner Sphere Spectrometric System as one of the most used, consisting of a detector placed in the center of a set of polyethylene spheres whose diameters range from 2 to 18 inches, however has some disadvantages such as the long periods of time to perform the measurements, the weight and the spheres number that vary according to the system. From this, alternative methods such as artificial neural networks are proposed. For this project neural networks of reverse propagation were used with the methodology of robust design of artificial neural networks, with the aid of a computational tool that maximizes the performance, making the time used for the training s of the network is the smallest possible and thus gets the orthogonal fixes quickly to determine the best network topology. The counting rates of a spectrometric system with 7 spheres, 2 spheres and one sphere of 5 and 8 inches were used. This methodology seeks to reduce the work used as in the spectrometric system formed by a greater number of spheres, since to enter less data in the counting rates to obtain the spectra with 60 energy levels saves time and space, because at having a smaller number of spheres its portability is easier to move from one place to another, for this we performed several experiments with different errors until we reached the optimal error so that the topology of the network was appropriate and find the best design parameters. A statistical software JMP was also used to obtain the best topologies and thus to retrain obtaining its best and worst spectra, in order to determine if the reduction is possible. (Author)

  20. Average number of neutrons in π-p, π-n, and π-12C interactions at 4 GeV/c

    International Nuclear Information System (INIS)

    Bekmirzaev, R.N.; Grishin, V.G.; Muminov, M.M.; Suvanov, I.; Trka, Z.; Trkova, J.

    1984-01-01

    The average numbers of secondary neutrons in π - p, π - n, and π -12 C interactions at 4 GeV/c have been determined by investigating secondary neutral stars produced by neutrons in a propane bubble chamber. The following values were obtained for the charge-exchange coefficients: α(p→n) = 0.39 +- 0.04 and α(n→p) = 0.37 +- 0.08

  1. A simple testable model of baryon number violation: Baryogenesis, dark matter, neutron-antineutron oscillation and collider signals

    Science.gov (United States)

    Allahverdi, Rouzbeh; Dev, P. S. Bhupal; Dutta, Bhaskar

    2018-04-01

    We study a simple TeV-scale model of baryon number violation which explains the observed proximity of the dark matter and baryon abundances. The model has constraints arising from both low and high-energy processes, and in particular, predicts a sizable rate for the neutron-antineutron (n - n bar) oscillation at low energy and the monojet signal at the LHC. We find an interesting complementarity among the constraints arising from the observed baryon asymmetry, ratio of dark matter and baryon abundances, n - n bar oscillation lifetime and the LHC monojet signal. There are regions in the parameter space where the n - n bar oscillation lifetime is found to be more constraining than the LHC constraints, which illustrates the importance of the next-generation n - n bar oscillation experiments.

  2. Do neutron stars disprove multiplicative creation in Dirac's large number hypothesis

    International Nuclear Information System (INIS)

    Qadir, A.; Mufti, A.A.

    1980-07-01

    Dirac's cosmology, based on his large number hypothesis, took the gravitational coupling to be decreasing with time and matter to be created as the square of time. Since the effects predicted by Dirac's theory are very small, it is difficult to find a ''clean'' test for it. Here we show that the observed radiation from pulsars is inconsistent with Dirac's multiplicative creation model, in which the matter created is proportional to the density of matter already present. Of course, this discussion makes no comment on the ''additive creation'' model, or on the revised version of Dirac's theory. (author)

  3. Determination of mercury in urine through Neutron activation analysis in dentists, as a measure of occupational exposure; Determinacion de mercurio en orina mediante analisis por activacion neutronica en odontologos, como una medida de exposicion ocupacional

    Energy Technology Data Exchange (ETDEWEB)

    Padilla M, M.A

    2000-07-01

    The mercury level was studied in urine to a dentists group belonging at the Universidad Autonoma del Estado de Mexico to determine the grade of contamination to the exposure of this element during their occupational activity. It was used the Neutron activation analysis which is an analytical method based in the irradiation with neutrons toward a stable nuclide. This can suffer a nuclear transformation to produce a radioactive nuclide and so it will be able to realize a quantitative analysis of itself. The TRIGA Mark III Reactor at the Nuclear Center in Mexico was used to realize this type of analysis due to the neutron fluxes which can be obtained as well as to the facilities in the irradiation of the sample.The purpose of this work is to determine the concentrations of mercury in the occupational exposed personnel such as dentists and so giving the recommendations of safety required to their production. (Author)

  4. Implication of nonintegral occupation number and Fermi-Dirac statistics in the local-spin-density approximation applied to finite systems

    International Nuclear Information System (INIS)

    Dhar, S.

    1989-01-01

    In electronic-structure calculations for finite systems using the local-spin-density (LSD) approximation, it is assumed that the eigenvalues of the Kohn-Sham equation should obey Fermi-Dirac (FD) statistics. In order to comply with this assumption for some of the transition-metal atoms, a nonintegral occupation number is used which also minimizes the total energy. It is shown here that for finite systems it is not necessary that the eigenvalues of the Kohn-Sham equation obey FD statistics. It is also shown that the Kohn-Sham exchange potential used in all LSD models is correct only for integer occupation number. With a noninteger occupation number the LSD exchange potential will be smaller than that given by the Kohn-Sham potential. Ab initio self-consistent spin-polarized calculations have been performed numerically for the total energy of an iron atom. It is found that the ground state belongs to the 3d 6 4s 2 configuration. The ionization potentials of all the Fe/sup n/ + ions are reported and are in agreement with experiment

  5. Occupational doses due to photoneutrons in medical linear accelerators rooms; Doses ocupacionais devido a neutrons em salas de aceleradores lineares de uso medico

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Alessandro Facure Neves de Salles

    2006-04-15

    Medical linear accelerators, with maximum photon energies above 10 MeV, are becoming of common use in Brazil. Although desirable in the therapeutic point of view, the increase in photon energies causes the generation of undesired neutrons, which are produced through nuclear reactions between photons and the high Z target nuclei of the materials that constitute the accelerator head. In this work, MCNP simulation was undertaken to examine the neutron equivalent doses around the accelerators head and at the entrance of medical linear accelerators treatment rooms, some of them licensed in Brazil by the National Regulatory Agency (CNEN). The simulated neutron dose equivalents varied between 2 e 26 {mu} Sv/Gy{sub RX}, and the results were compared with calculations performed with the use of some semi-empirical equations found in literature. It was found that the semi-empirical equations underestimate the simulated neutron doses in the majority of the cases, if compared to the simulated values, suggesting that these equations must be revised, due to the increasing number of high energy machines in the country. (author)

  6. Neutron-neutron probe for uranium exploration

    International Nuclear Information System (INIS)

    Smith, R.C.

    1979-01-01

    A neutron activation probe for assaying the amount of fissionable isotopes in an ore body is described which comprises a casing which is movable through a borehole in the ore body, a neutron source and a number of delayed neutron detectors arranged colinearly in the casing below the neutron source for detecting delayed neutrons

  7. Comparison of pressure vessel neutron fluences for the Balakovo-3 reactor with measurements and investigation of the influence of neutron cross sections and number of groups on the results

    Energy Technology Data Exchange (ETDEWEB)

    Barz, H U; Boehmer, B; Konheiser, J; Stephan, I

    1998-10-01

    The general methodical questions of experimental and theoretical determination of neutron fluences have been described in connection with the measurements and 3-D Monte Carlo calculation for the Rovno-3 reactor. The same calculation and measurement methods were applied for the Balakovo-3 reactor. In the first part, the results of the comparison for Balakovo will be given and discussed. However, for this reactor the main attention was focussed on investigations of the accuracy of the calculation. In this connection an important question is the influence of neutron data on the results. With this respect not only the source of the data but also the number of energy groups is important. (orig.)

  8. Estimating upper bounds for occupancy and number of manatees in areas potentially affected by oil from the Deepwater Horizon oil spill.

    Directory of Open Access Journals (Sweden)

    Julien Martin

    Full Text Available The explosion of the Deepwater Horizon drilling platform created the largest marine oil spill in U.S. history. As part of the Natural Resource Damage Assessment process, we applied an innovative modeling approach to obtain upper estimates for occupancy and for number of manatees in areas potentially affected by the oil spill. Our data consisted of aerial survey counts in waters of the Florida Panhandle, Alabama and Mississippi. Our method, which uses a Bayesian approach, allows for the propagation of uncertainty associated with estimates from empirical data and from the published literature. We illustrate that it is possible to derive estimates of occupancy rate and upper estimates of the number of manatees present at the time of sampling, even when no manatees were observed in our sampled plots during surveys. We estimated that fewer than 2.4% of potentially affected manatee habitat in our Florida study area may have been occupied by manatees. The upper estimate for the number of manatees present in potentially impacted areas (within our study area was estimated with our model to be 74 (95%CI 46 to 107. This upper estimate for the number of manatees was conditioned on the upper 95%CI value of the occupancy rate. In other words, based on our estimates, it is highly probable that there were 107 or fewer manatees in our study area during the time of our surveys. Because our analyses apply to habitats considered likely manatee habitats, our inference is restricted to these sites and to the time frame of our surveys. Given that manatees may be hard to see during aerial surveys, it was important to account for imperfect detection. The approach that we described can be useful for determining the best allocation of resources for monitoring and conservation.

  9. Prediction of the number of 14 MeV neutron elastically scattered from large sample of aluminium using Monte Carlo simulation method

    International Nuclear Information System (INIS)

    Husin Wagiran; Wan Mohd Nasir Wan Kadir

    1997-01-01

    In neutron scattering processes, the effect of multiple scattering is to cause an effective increase in the measured cross-sections due to increase on the probability of neutron scattering interactions in the sample. Analysis of how the effective cross-section varies with thickness is very complicated due to complicated sample geometries and the variations of scattering cross-section with energy. Monte Carlo method is one of the possible method for treating the multiple scattering processes in the extended sample. In this method a lot of approximations have to be made and the accurate data of microscopic cross-sections are needed at various angles. In the present work, a Monte Carlo simulation programme suitable for a small computer was developed. The programme was capable to predict the number of neutrons scattered from various thickness of aluminium samples at all possible angles between 00 to 36011 with 100 increments. In order to make the the programme not too complicated and capable of being run on microcomputer with reasonable time, the calculations was done in two dimension coordinate system. The number of neutrons predicted from this model show in good agreement with previous experimental results

  10. The influence of the number of activation detectors on the Seibersdorf - Milano intercomparison of neutron flux density spectra by WINDOWS code

    International Nuclear Information System (INIS)

    Ertek, C.

    1981-02-01

    This work is a continuation of the work performed within the IAEA programme on standardization of reactor radiation measurements, one of the important objectives of which is the assistance to laboratories in Member States to implement or intercompare the multiple foil activation techniques for different neutron field measurements. The importance of these techniques is well recognized. In CESNEF-FERMI Politecnico di Milano, Italy, they have installed near the core of a water boiler of 50kW, a neutron filter made of B 4 C in order to obtain a neutron flux density spectrum that could be of utility in intercalibration problems connected with irradiation in fast assemblies. Dr. V. Sangiust from CESNEF kindly sent the input guess neutron flux density spectrum and a series of measured reaction rates to be treated by the IAEA Seibersdorf laboratory using the SAND-II and the WINDOWS unfolding codes. The meaningful comparison using partly the same ENDF/B IV cross section data is performed. In the present work we extended the investiga tion using WINDOWS unfolding code for different numbers of activation fo ils or reaction rates

  11. Occupational cancer

    International Nuclear Information System (INIS)

    Choril, A.C.; McCracken, W.J.; Dowd, E.C.; Stewart, Charles; Burton, D.F.; Dyer, D.W.

    1981-01-01

    This paper reviews the experience of the Workmen's Compensation Board of Ontario in identifying cases of cancer that could be attributed to occupational hazards. Workers' claims for compensation are allowed if there is reasonable medical evidence that their cancer was caused by exposure to risk factors associated with their occupation. Details of the types of cancers associated with specific carcinogens or fields of employment are discussed. About 50% of the cases were related to exposure in particular industrial operations that functioned for relatively brief periods. The number of deaths from cancer identified as being caused by occupational factors is compared with the total for cancer from all causes in Ontario during the period 1971 through 1975. Although all workers eligible for compensation may not have been identified, the data suggest that less than 1% is presently caused by occupational factors

  12. Comparative study of Monte Carlo particle transport code PHITS and nuclear data processing code NJOY for PKA energy spectra and heating number under neutron irradiation

    International Nuclear Information System (INIS)

    Iwamoto, Y.; Ogawa, T.

    2016-01-01

    The modelling of the damage in materials irradiated by neutrons is needed for understanding the mechanism of radiation damage in fission and fusion reactor facilities. The molecular dynamics simulations of damage cascades with full atomic interactions require information about the energy distribution of the Primary Knock on Atoms (PKAs). The most common process to calculate PKA energy spectra under low-energy neutron irradiation is to use the nuclear data processing code NJOY2012. It calculates group-to-group recoil cross section matrices using nuclear data libraries in ENDF data format, which is energy and angular recoil distributions for many reactions. After the NJOY2012 process, SPKA6C is employed to produce PKA energy spectra combining recoil cross section matrices with an incident neutron energy spectrum. However, intercomparison with different processes and nuclear data libraries has not been studied yet. Especially, the higher energy (~5 MeV) of the incident neutrons, compared to fission, leads to many reaction channels, which produces a complex distribution of PKAs in energy and type. Recently, we have developed the event generator mode (EGM) in the Particle and Heavy Ion Transport code System PHITS for neutron incident reactions in the energy region below 20 MeV. The main feature of EGM is to produce PKA with keeping energy and momentum conservation in a reaction. It is used for event-by-event analysis in application fields such as soft error analysis in semiconductors, micro dosimetry in human body, and estimation of Displacement per Atoms (DPA) value in metals and so on. The purpose of this work is to specify differences of PKA spectra and heating number related with kerma between different calculation method using PHITS-EGM and NJOY2012+SPKA6C with different libraries TENDL-2015, ENDF/B-VII.1 and JENDL-4.0 for fusion relevant materials

  13. The Determination of Neutron-Induced Reaction Cross Section Data on Even-Even, Magic- Number Nuclide Chromium 52 Using EXIFON Code

    International Nuclear Information System (INIS)

    Jonah, S.A.

    2013-01-01

    The EXIFON code version 2.0 is a calculational tool, which is based on both many-body theory and random matrix physics. In this work, it has been used to calculate neutron induced reaction cross section data from 0 to 20 MeV on an even-even, magic number nuclide 52 Cr with neutron number, N=28. Specifically, the (n,p), (n,α) and (n,2n) reaction cross section data were calculated as functions of incident energy of neutrons. Data obtained from the experimental data in the IAEA, EXFOR data Library and recommended data libraries around the globe, JENDL, ENDF and JEFF were used to validate the calculated data. The data indicate that the calculated data without shell corrections are in good agreement with experimental data as well as the recommended data from the evaluated data libraries. The calculated results could provide useful insight into the choice of some input parameters near closed shells using the EXIFON code.

  14. Evolution of uranium fission-fragment charge yields with neutron number. Strong effect of multi-chance fission on yield asymmetries

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, Peter [Los Alamos National Laboratory, Theoretical Division, Los Alamos, NM (United States); Schmitt, Christelle [CEA/DSM-CNRS/IN2P3, Grand Accelerateur National d' Ions Lourds, Caen (France)

    2017-01-15

    We use the Brownian shape-motion model, with its recent extensions, which allow modeling of odd-even staggering, to calculate the evolution of fission-fragment charge distributions with neutron number for the compound-system sequence {sup 234}U, {sup 236}U, {sup 238}U, and {sup 240}U. We compare to experimental data where available, for neutron- and electromagnetic-induced fission over a compound-nucleus excitation energy range from about 6 to 20 MeV. A notable result of the study is that the evolution of the location of the peak charge yield from Z = 54 in {sup 234}U towards Z = 52 in heavier isotopes, seen in the experimental data, is present also in the calculated yields. We further show that to describe yields at higher compound-nucleus excitation energies, then, already at 20 MeV, it is necessary to take multi-chance fission into account. (orig.)

  15. Human circulating plasma DNA significantly decreases while lymphocyte DNA damage increases under chronic occupational exposure to low-dose gamma-neutron and tritium β-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Korzeneva, Inna B., E-mail: inna.korzeneva@molgen.vniief.ru [Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190, Sarov, 37 Mira ave., Nizhniy Novgorod Region (Russian Federation); Kostuyk, Svetlana V.; Ershova, Liza S. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); Osipov, Andrian N. [Federal Medial and Biological Center named after Burnazyan of the Federal Medical and Biological Agency (FMBTz named after Burnazyan of FMBA), Moscow (Russian Federation); State Research Center - Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency, Zhivopisnaya, 46, Moscow, 123098 (Russian Federation); Zhuravleva, Veronika F.; Pankratova, Galina V. [Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190, Sarov, 37 Mira ave., Nizhniy Novgorod Region (Russian Federation); Porokhovnik, Lev N.; Veiko, Natalia N. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, 115478 Moscow, 1 Moskvorechye str. (Russian Federation)

    2015-09-15

    Highlights: • The chronic exposure to low-dose IR induces DSBs in human lymphocytes (TM index). • Exposure to IR decreases the level of human circulating DNA (cfDNA index). • IR induces an increase of DNase1 activity (DNase1 index) in plasma. • IR induces an increase of the level of antibodies to DNA (Ab DNA index) in plasma. • The ratio cfDNA/(DNase 1 × Ab DNA × TM) is a potential marker of human exposure to IR. - Abstract: The blood plasma of healthy people contains cell-fee (circulating) DNA (cfDNA). Apoptotic cells are the main source of the cfDNA. The cfDNA concentration increases in case of the organism’s cell death rate increase, for example in case of exposure to high-dose ionizing radiation (IR). The objects of the present research are the blood plasma and blood lymphocytes of people, who contacted occupationally with the sources of external gamma/neutron radiation or internal β-radiation of tritium N = 176). As the controls (references), blood samples of people, who had never been occupationally subjected to the IR sources, were used (N = 109). With respect to the plasma samples of each donor there were defined: the cfDNA concentration (the cfDNA index), DNase1 activity (the DNase1 index) and titre of antibodies to DNA (the Ab DNA index). The general DNA damage in the cells was defined (using the Comet assay, the tail moment (TM) index). A chronic effect of the low-dose ionizing radiation on a human being is accompanied by the enhancement of the DNA damage in lymphocytes along with a considerable cfDNA content reduction, while the DNase1 content and concentration of antibodies to DNA (Ab DNA) increase. All the aforementioned changes were also observed in people, who had not worked with the IR sources for more than a year. The ratio cfDNA/(DNase1 × Ab DNA × TM) is proposed to be used as a marker of the chronic exposure of a person to the external low-dose IR. It was formulated the assumption that the joint analysis of the cfDNA, DNase1, Ab

  16. Human circulating plasma DNA significantly decreases while lymphocyte DNA damage increases under chronic occupational exposure to low-dose gamma-neutron and tritium β-radiation.

    Science.gov (United States)

    Korzeneva, Inna B; Kostuyk, Svetlana V; Ershova, Liza S; Osipov, Andrian N; Zhuravleva, Veronika F; Pankratova, Galina V; Porokhovnik, Lev N; Veiko, Natalia N

    2015-09-01

    The blood plasma of healthy people contains cell-fee (circulating) DNA (cfDNA). Apoptotic cells are the main source of the cfDNA. The cfDNA concentration increases in case of the organism's cell death rate increase, for example in case of exposure to high-dose ionizing radiation (IR). The objects of the present research are the blood plasma and blood lymphocytes of people, who contacted occupationally with the sources of external gamma/neutron radiation or internal β-radiation of tritium N = 176). As the controls (references), blood samples of people, who had never been occupationally subjected to the IR sources, were used (N = 109). With respect to the plasma samples of each donor there were defined: the cfDNA concentration (the cfDNA index), DNase1 activity (the DNase1 index) and titre of antibodies to DNA (the Ab DNA index). The general DNA damage in the cells was defined (using the Comet assay, the tail moment (TM) index). A chronic effect of the low-dose ionizing radiation on a human being is accompanied by the enhancement of the DNA damage in lymphocytes along with a considerable cfDNA content reduction, while the DNase1 content and concentration of antibodies to DNA (Ab DNA) increase. All the aforementioned changes were also observed in people, who had not worked with the IR sources for more than a year. The ratio cfDNA/(DNase1×Ab DNA × TM) is proposed to be used as a marker of the chronic exposure of a person to the external low-dose IR. It was formulated the assumption that the joint analysis of the cfDNA, DNase1, Ab DNA and TM values may provide the information about the human organism's cell resistivity to chronic exposure to the low-dose IR and about the development of the adaptive response in the organism that is aimed, firstly, at the effective cfDNA elimination from the blood circulation, and, secondly - at survival of the cells, including the cells with the damaged DNA. Copyright © 2015. Published by Elsevier B.V.

  17. Occupational Clusters.

    Science.gov (United States)

    Pottawattamie County School System, Council Bluffs, IA.

    The 15 occupational clusters (transportation, fine arts and humanities, communications and media, personal service occupations, construction, hospitality and recreation, health occupations, marine science occupations, consumer and homemaking-related occupations, agribusiness and natural resources, environment, public service, business and office…

  18. Neutron detector

    Science.gov (United States)

    Stephan, Andrew C [Knoxville, TN; Jardret,; Vincent, D [Powell, TN

    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.

  19. Estimation of the contribution of neutrons to the equivalent dose for personnel occupationally exposed and public in medical facilities: X-ray with energy equal or greater than 10MV

    International Nuclear Information System (INIS)

    Gonzalez, Alfonso Mayer; Jimenez, Roberto Ortega; Sanchez, Mario A. Reyes; Moranchel y Mejia, Mario

    2013-01-01

    In Mexico the use of electron accelerators for treating cancerous tumors had grown enormously in the last decade. When the treatments are carried out with X-ray beam energy below 10 MV the design of the shielding of the radioactive facility is determined by analyzing the interaction of X-rays, which have a direct impact and dispersion, with materials of the facility. However, when it makes use of X-ray beam energy equal to or greater than 10 MV the neutrons presence is imminent due to their generation by the interaction of the primary beam X-ray with materials head of the accelerator and of the table of treatment, mainly. In these cases, the design and calculation of shielding considers the generation of high-energy neutrons which contribute the equivalent dose that public and Occupationally Staff Exposed (POE) will receive in the areas surrounding the facility radioactive. However, very few measurements have been performed to determine the actual contribution to the neutron dose equivalent received by POE and public during working hours. This paper presents an estimate of the actual contribution of the neutron dose equivalent received by public and POE facilities in various radioactive medical use, considering many factors. To this end, measurements were made of the equivalent dose by using a neutron monitor in areas surrounding different radioactive installations (of Mexico) which used electron accelerators medical use during treatment with X-ray beam energy equal to or greater than 10 MV. The results are presented after a statistical analysis of a wide range of measures in order to estimate more reliability real contribution of the neutron dose equivalent for POE and the public. (author)

  20. FINAL REPORT: DOE CONTRACT NUMBER FG0205ER64026 Biological Neutron Scattering: A Collaboration with the Oak Ridge Center for Structural Molecular Biology

    Energy Technology Data Exchange (ETDEWEB)

    Trewhella, Jill [Univ. of Utah, Salt Lake City, UT (United States)

    2011-01-12

    The overarching goal of this project was to promote applications of small-angle scattering in structural molecular biology by providing model examples of cutting edge applications that demonstrate the unique capabilities and potential of the DOE national user facilities at Oak Ridge, especially the newly commissioned BioSANS. The approach taken was three-fold: (1) to engage in high impact collaborative research projects that would benefit from small-angle neutron scattering to both demonstrate the power of the technique while expanding the potential user community; (2) to provide access to scattering facilities established at the University of Utah to as broad a set of researchers as possible to increase the expertise in small-angle scattering generally; and (3) to develop new methods and tools for small-angle scattering. To these ends, three major research collaborations were pursued that resulted in a significant body of published work where neutron scattering and contrast variation played a major role. These major collaborations involved studies of protein complexes involved in (1) bacterial transcription regulation and adaptive response (a DOE/BER priority area); (2) regulation of cardiac muscle; and (3) neuronal disorders. In addition, to broaden the impact of the project, smaller collaborative efforts were supported that used either small-angle X-ray or neutron scattering. Finally, the DOE supported facilities at the University of Utah were made available to researchers on a service basis and a number of independent groups took advantage of this opportunity. In all of this work, there was an emphasis on the training of students and post docs in scattering techniques, and a set of publications (a book chapter, a review, and an encyclopedia article) were produced to guide the non-specialist potential user of scattering techniques in successful applications of the techniques. We also developed a suite of user friendly web-based computational tools currently

  1. The development of neutron activation, sample transportation and γ-ray counting routine system for numbers of geological samples

    International Nuclear Information System (INIS)

    Shibata Shin-nosuke; Tanaka, Tsuyoshi; Minami, Masayo

    2001-01-01

    A new gamma-ray counting and data processing system for non-destructive neutron activation analysis has been set up in Radioisotope Center in Nagoya University. The system carry out gamma-ray counting, sample change and data processing automatically, and is able to keep us away from parts of complicated operations in INAA. In this study, we have arranged simple analytical procedure that makes practical works easier than previous. The concrete flow is described from the reparation of powder rock samples to gamma-ray counting and data processing by the new INAA system. Then it is run over that the analyses used two Geological Survey of Japan rock reference samples JB-1a and JG-1a in order to evaluate how the new analytical procedure give any speediness and accuracy for analyses of geological materials. Two United States Geological Survey reference samples BCR-1 and G-2 used as the standard respectively. Twenty two elements for JB-1a and 25 elements for JG-1a were analyzed, the uncertainty are <5% for Na, Sc, Fe, Co, La, Ce, Sm, Eu, Yb, Lu, Hf, Ta and Th, and of <10% for Cr, Zn, Cs, Ba, Nd, Tb and U. This system will enable us to analyze more than 1500 geologic samples per year. (author)

  2. Optimization of the architecture of a neural network in neutron spectrometry to reduce the number of Bonner spheres; Optimizacion de la arquitectura de una red neuronal en espectrometria de neutrones para reducer el numero de esferas Bonner

    Energy Technology Data Exchange (ETDEWEB)

    Leon P, A. A.; Martinez B, M. R.; Hernandez P, C. F.; Espinoza G, J. G.; Castaneda M, V. H.; Solis S, L. O.; Castaneda M, R.; Ortiz R, J. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Av. Ramon Lopez Velarde 801, Col. Centro, 98000 Zacatecas, Zac. (Mexico); Mendez V, R. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Laboratorio de Patrones Neutronicos, Av. Complutense 22, 28040 Madrid (Spain); Gallego, E. [Universidad Politecnica de Madrid, Departamento de Ingenieria Nuclear, ETSI Industriales, Jose Gutierrez Abascal 2, 28006 Madrid (Spain); De Sousa L, M. A. [Centro de Desenvolvimento da Tecnologia Nuclear / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Pampulha, Belo Horizonte, Minas Gerais (Brazil)

    2016-10-15

    The neutron spectrometry is an experimental process for determining the energy distribution called the Spectrum. Among the methods available for neutron spectrometry, one can mention the Bonner Sphere Spectrometric System as one of the most used, consisting of a detector placed in the center of a set of polyethylene spheres whose diameters range from 2 to 18 inches, however has some disadvantages such as the long periods of time to perform the measurements, the weight and the spheres number that vary according to the system. From this, alternative methods such as artificial neural networks are proposed. For this project neural networks of reverse propagation were used with the methodology of robust design of artificial neural networks, with the aid of a computational tool that maximizes the performance, making the time used for the training s of the network is the smallest possible and thus gets the orthogonal fixes quickly to determine the best network topology. The counting rates of a spectrometric system with 7 spheres, 2 spheres and one sphere of 5 and 8 inches were used. This methodology seeks to reduce the work used as in the spectrometric system formed by a greater number of spheres, since to enter less data in the counting rates to obtain the spectra with 60 energy levels saves time and space, because at having a smaller number of spheres its portability is easier to move from one place to another, for this we performed several experiments with different errors until we reached the optimal error so that the topology of the network was appropriate and find the best design parameters. A statistical software JMP was also used to obtain the best topologies and thus to retrain obtaining its best and worst spectra, in order to determine if the reduction is possible. (Author)

  3. Neutron polarization

    International Nuclear Information System (INIS)

    Firk, F.W.K.

    1976-01-01

    Some recent experiments involving polarized neutrons are discussed; they demonstrate how polarization studies provide information on fundamental aspects of nuclear structure that cannot be obtained from more traditional neutron studies. Until recently, neutron polarization studies tended to be limited either to very low energies or to restricted regions at higher energies, determined by the kinematics of favorable (p, vector n) and (d, vector n) reactions. With the advent of high intensity pulsed electron and proton accelerators and of beams of vector polarized deuterons, this is no longer the case. One has entered an era in which neutron polarization experiments are now being carried out, in a routine way, throughout the entire range from thermal energies to tens-of-MeV. The significance of neutron polarization studies is illustrated in discussions of a wide variety of experiments that include the measurement of T-invariance in the β-decay of polarized neutrons, a search for the effects of meson exchange currents in the photo-disintegration of the deuteron, the determination of quantum numbers of states in the fission of aligned 235 U and 237 Np induced by polarized neutrons, and the double- and triple-scattering of fast neutrons by light nuclei

  4. Estimation of the contribution by neutrons to the equivalent dose for exposed occupationally personnel and people in medical use facilities: X rays of equal or superior energy to 10 MV; Estimacion de la contribucion por neutrones a la dosis equivalente para personal ocupacionalmente expuesto y publico en instalaciones de uso medico: rayos X de energia igual y/o superior a 10 MV

    Energy Technology Data Exchange (ETDEWEB)

    Ortega J, R.; Reyes S, M. A. [Comision Nacional de Seguridad Nuclear y Salvaguardias, Dr. Jose Ma. Barragan 779, Col. Narvarte, 03020 Mexico D. F. (Mexico); Moranchel y R, M., E-mail: rojimenez@cnsns.gob.mx [IPN, Escuela Superior de Fisica y Matematicas, Departamento de Ingenieria Nuclear, Av. Instituto Politecnico Nacional s/n, U. P. Adolfo Lopez Mateos, Edif. 9, Col. San Pedro Zacatenco, 07738 Mexico D. F. (Mexico)

    2013-10-15

    In Mexico the use of electron accelerators for treating cancerous tumors had grown enormously in the last decade. When the treatments are carried out with X-ray beam energy below 10 MV the design of the shielding of the radioactive facility is determined by analyzing the interaction of X-rays, which have a direct impact and dispersion, with materials of the facility. However, when it makes use of X-ray beam energy equal to or greater than 10 MV the neutrons presence is imminent due to their generation by the interaction of the primary beam X-ray with materials head of the accelerator and of the table of treatment, mainly. In these cases, the design and calculation of shielding considers the generation of high-energy neutrons which contribute the equivalent dose that public and occupationally staff exposed (POE) will receive in the areas surrounding the facility radioactive. However, very few measurements have been performed to determine the actual contribution to the neutron dose equivalent received by POE and public during working hours. This paper presents and estimate of the actual contribution of the neutron dose equivalent received by public and POE facilities in various radioactive medical use, considering many factors. To this end, measurements were made of the equivalent dose by using a neutron monitor in areas surrounding different radioactive installations (of Mexico) which used electron accelerators medical use during treatment with X-ray beam energy equal to or greater than 10 MV. The results are presented after a statistical analysis of a wide range of measures in order to estimate more reliability real contribution of the neutron dose equivalent for POE and the public. (author)

  5. Estimation of the contribution of neutrons to the equivalent dose for personnel occupationally exposed and public in medical facilities: X-ray with energy equal or greater than 10MV; Estimacion de la contribucion por neutrones a la dosis equivalente para personal ocupacionalmente expuesto y publico en instalaciones de uso medico: rayos X de energia igual y/o superior a 10MV

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Alfonso Mayer; Jimenez, Roberto Ortega; Sanchez, Mario A. Reyes, E-mail: amgesfm@hotmail.com, E-mail: rojimenez@cnsns.gob.mx [Comision Nacional de Seguridad Nuclear y Salvaguardias (CNSNS), Mexico, D.F. (Mexico); Moranchel y Mejia, Mario, E-mail: mmoranchel@ipn.mx [Instituto Politecnico Nacional (ESFM/IPN), Mexico, D.F. (Mexico). Escuela Superior de Fisica y Matematicas. Departamento de lngenieria Nuclear

    2013-07-01

    In Mexico the use of electron accelerators for treating cancerous tumors had grown enormously in the last decade. When the treatments are carried out with X-ray beam energy below 10 MV the design of the shielding of the radioactive facility is determined by analyzing the interaction of X-rays, which have a direct impact and dispersion, with materials of the facility. However, when it makes use of X-ray beam energy equal to or greater than 10 MV the neutrons presence is imminent due to their generation by the interaction of the primary beam X-ray with materials head of the accelerator and of the table of treatment, mainly. In these cases, the design and calculation of shielding considers the generation of high-energy neutrons which contribute the equivalent dose that public and Occupationally Staff Exposed (POE) will receive in the areas surrounding the facility radioactive. However, very few measurements have been performed to determine the actual contribution to the neutron dose equivalent received by POE and public during working hours. This paper presents an estimate of the actual contribution of the neutron dose equivalent received by public and POE facilities in various radioactive medical use, considering many factors. To this end, measurements were made of the equivalent dose by using a neutron monitor in areas surrounding different radioactive installations (of Mexico) which used electron accelerators medical use during treatment with X-ray beam energy equal to or greater than 10 MV. The results are presented after a statistical analysis of a wide range of measures in order to estimate more reliability real contribution of the neutron dose equivalent for POE and the public. (author)

  6. Systematic approach to personnel neutron monitoring

    International Nuclear Information System (INIS)

    Griffith, R.V.; Hankins, D.E.

    1980-01-01

    NTA film and albedo detectors represent the major portion of personnel dosimeters now used for occupational neutron monitoring. However, recent attention to the spectral response of these systems has demonstrated the need for detectors that have a better match to the fields being monitored. Recent developments in direct recoil track etch dosimeters present some intriguing alternatives, and careful use of 237 Np fission fragment detectors offers the advantage of a good dose equivalent spectral match. Work continues on a number of other new detector mechanisms, but problems with sensitivity, energy response, gamma interference, etc., continue to prevent development of most mechanisms into viable personnel dosimeters. Current dosimeter limitations make a systematic approach to personnel neutron monitoring particularly important. Techniques have been developed and tested, using available portable survey instruments, that significantly improve the quality of dosimeter interpretation. Even simple spectrometry can be done with modest effort, significantly improving the health physicists ability to provide accurate neutron monitoring

  7. Dependency of neutron power function S0 from mass number in the area of 100 < A < 140

    Directory of Open Access Journals (Sweden)

    M. M. Pravdivy

    2014-09-01

    Full Text Available Resume of some previous investigations concerning definition of full sets of average resonances parameters S0, S1, , , S1,1/2, S1,3/2 for nuclei 47,9Ti, 55,8Fe, 58,7Ni, 65,4Zn, 72,6Ge, 79Se, 91,2Zr, 95,9Mo, 101,1Ru, 106,4Pd, 106Cd, 108Cd, 110Cd, 112Cd, 116Cd, 116Sn, 118Sn, 120Sn, 122Sn, 124Sn, 127,6Te, 144,2Nd has been presented and the place of these sets in the existing system of recommended parameters has been shown. The explored dependency power func-tion S0 from mass number in the area of 100 < A < 140 was studied.

  8. Neutron stars

    International Nuclear Information System (INIS)

    Irvine, J.M.

    1978-01-01

    The subject is covered in chapters entitled: introduction (resume of stellar evolution, gross characteristics of neutron stars); pulsars (pulsar characteristics, pulsars as neutron stars); neutron star temperatures (neutron star cooling, superfluidity and superconductivity in neutron stars); the exterior of neutron stars (the magnetosphere, the neutron star 'atmosphere', pulses); neutron star structure; neutron star equations of state. (U.K.)

  9. Does office space occupation matter? The role of the number of persons per enclosed office space, psychosocial work characteristics, and environmental satisfaction in the physical and mental health of employees.

    Science.gov (United States)

    Herbig, B; Schneider, A; Nowak, D

    2016-10-01

    The study examined the effects of office space occupation, psychosocial work characteristics, and environmental satisfaction on physical and mental health of office workers in small-sized and open-plan offices as well as possible underlying mechanisms. Office space occupation was characterized as number of persons per one enclosed office space. A total of 207 office employees with similar jobs in offices with different space occupation were surveyed regarding their work situation (psychosocial work characteristics, satisfaction with privacy, acoustics, and control) and health (psychosomatic complaints, irritation, mental well-being, and work ability). Binary logistic and linear regression analyses as well as bootstrapped mediation analyses were used to determine associations and underlying mechanisms. Employee health was significantly associated with all work characteristics. Psychosocial work stressors had the strongest relation to physical and mental health (OR range: 1.66-3.72). The effect of office space occupation on employee health was mediated by stressors and environmental satisfaction, but not by psychosocial work resources. As assumed by sociotechnical approaches, a higher number of persons per enclosed office space was associated with adverse health effects. However, the strongest associations were found with psychosocial work stressors. When revising office design, a holistic approach to work (re)design is needed. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Neutron in biology

    Energy Technology Data Exchange (ETDEWEB)

    Niimura, Nobuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-11-01

    Neutron in biology can provide an experimental method of directly locating relationship of proteins and DNA. However, there are relatively few experimental study of such objects since it takes a lot of time to collect a sufficient number of Bragg reflections and inelastic spectra due to the low flux of neutron illuminating the sample. Since a next generation neutron source of JAERI will be 5MW spallation neutron source and its effective neutron flux will be 10{sup 2} to 10{sup 3} times higher than the one of JRR-3M, neutron in biology will open a completely new world for structural biology. (author)

  11. Neutron in biology

    International Nuclear Information System (INIS)

    Niimura, Nobuo

    1997-01-01

    Neutron in biology can provide an experimental method of directly locating relationship of proteins and DNA. However, there are relatively few experimental study of such objects since it takes a lot of time to collect a sufficient number of Bragg reflections and inelastic spectra due to the low flux of neutron illuminating the sample. Since a next generation neutron source of JAERI will be 5MW spallation neutron source and its effective neutron flux will be 10 2 to 10 3 times higher than the one of JRR-3M, neutron in biology will open a completely new world for structural biology. (author)

  12. Neutron dosimeters and survey meters in accelerators, reactors and other neutron environments

    International Nuclear Information System (INIS)

    1989-03-01

    Neutron fields in occupationally accessible areas around nuclear reactors, radioisotope sources and medical and high energy accelerators have been characterized using currently available information. Neutron, rem meters, such as the Leake detector, are the most suitable instruments available for conducting neutron dose rate surveys in the vicinity of radioisotope neutron sources, nuclear reactors and medical accelerators. However, these instruments have been shown to be deficient in that they overrespond by a factor of four to neutrons in the 0.1 to 1 MeV range and are insensitive to neutrons from about 1 eV up to about 10 keV. Also, they are insensitive to neutrons above 20 MeV and their use must be restricted near high energy accelerators where significant numbers of neutrons above 20 MeV are known to be present. The most suitable instrument of measure dose from neutrons above 20 MeV is the 12 C(n,2n) 11 C scintillation chamber. Commercially available rem meters frequently use BF 3 counters in the pulse mode to detect thermal neutrons. Therefore, measurements around pulsed accelerators must be made with caution to ensure that the detector is not saturated during each pulse and that the accelerator pulse period is greater than the response time of the detector. The personal neutron dosimeters currently available either are known to be insensitive to neutrons above 20 MeV or have not been tested. Also, all except the albedo dosimeter are insensitive to or have not been tested for neutron energies in the range 1 eV to 10 keV. Several dosimeter types respond reasonably well to neutrons in the energy range 0.1 to 15 MeV, for example, CR-39, bubble and superheated drop detectors. However, the first gas a lower limit of sensitivity of about 0.3 mSv. The bubble detector can be designed to measure doses as small as 1μSv and offers the additional benefit of direct-reading capability. The superheated drop detector is not suitable for use around pulsed accelerators because

  13. Nucleus Z=126 with magic neutron number N=184 may be related to the measured Maruhn-Greiner maximum at A/2=155 from compound nuclei at low energy nuclear reactions

    Science.gov (United States)

    Prelas, M. A.; Hora, H.; Miley, G. H.

    2014-07-01

    Evaluation of nuclear binding energies from theory close to available measurements of a very high number of superheavy elements (SHE) based on α-decay energies Qα, arrived at a closing shell with a significant neutron number 184. Within the option of several discussed magic numbers for protons of around 120, Bagge's numbers 126 and 184 fit well and are supported by the element generation measurements by low energy nuclear reactions (LENR) discovered in deuterium loaded host metals. These measurements were showing a Maruhn-Greiner maximum from fission of compound nuclei in an excited state with double magic numbers for mutual confirmation.

  14. Occupational cancer

    International Nuclear Information System (INIS)

    Alderson, M.

    1986-01-01

    This book aims to review the occurrence and causes of occupational cancer and is aimed at assisting medical and safety staff, management and health and safety representatives. It is presented in the following chapters: 1) Epidemiological method 2) Agents causing occupationally induced cancer, including radiation 3) Occupations associated with risk of cancer 4) Aetiology of cancer 5) Control of occupationally induced cancer, research, prevention, legislation, national and international bodies, control of specific occupational carcinogens, including irradiation. (U.K.)

  15. Radiobiological basis for setting neutron radiation safety standards

    International Nuclear Information System (INIS)

    Straume, T.

    1985-01-01

    Present neutron standards, adopted more than 20 yr ago from a weak radiobiological data base, have been in doubt for a number of years and are currently under challenge. Moreover, recent dosimetric re-evaluations indicate that Hiroshima neutron doses may have been much lower than previously thought, suggesting that direct data for neutron-induced cancer in humans may in fact not be available. These recent developments make it urgent to determine the extent to which neutron cancer risk in man can be estimated from data that are available. Two approaches are proposed here that are anchored in particularly robust epidemiological and experimental data and appear most likely to provide reliable estimates of neutron cancer risk in man. The first approach uses gamma-ray dose-response relationships for human carcinogenesis, available from Nagasaki (Hiroshima data are also considered), together with highly characterized neutron and gamma-ray data for human cytogenetics. When tested against relevant experimental data, this approach either adequately predicts or somewhat overestimates neutron tumorigenesis (and mutagenesis) in animals. The second approach also uses the Nagasaki gamma-ray cancer data, but together with neutron RBEs from animal tumorigenesis studies. Both approaches give similar results and provide a basis for setting neutron radiation safety standards. They appear to be an improvement over previous approaches, including those that rely on highly uncertain maximum neutron RBEs and unnecessary extrapolations of gamma-ray data to very low doses. Results suggest that, at the presently accepted neutron dose limit of 0.5 rad/yr, the cancer mortality risk to radiation workers is not very different from accidental mortality risks to workers in various nonradiation occupations

  16. Study of the neutron strength function and of the diffusion radius as a function of mass number; Etude de la fonction densite de neutron et du rayon de diffusion en fonction du nombre de masse

    Energy Technology Data Exchange (ETDEWEB)

    Morgenstern, J [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires

    1968-09-01

    The strength functions S{sub 0} and S{sub 1}, and the scattering length R' are studied. The values of S{sub 0}, S{sub 1} and R' are obtained by shape analysis of the individual resonances observed in total neutron cross-section measurements. These measurements were performed at the Saclay 45 MeV linac by the time of flight method. The best resolution achieved was equal to 0.19 ns/m. We have particularly studied the nuclei around number of mass A = 50, 90, 140 and 200. The experimental values of S{sub 0}, S{sub 1} and R' are compared with optical model calculations. A fairly good agreement is obtained using an optical potential with surface absorption. (author) [French] Nous etudions les fonctions densite S{sub 0} et S{sub 1} ainsi que le rayon de diffusion R'. Les valeurs de S{sub 0}, S{sub 1} et R' sont determinees a partir de l'analyse de forme des resonances individuelles observees lors de la mesure de la section efficace neutronique totale. Cette mesure a ete faite aupres de l'accelerateur lineaire d'electrons de 45 MeV de Saclay par la methode du temps de vol. La meilleure resolution atteinte etait egale a 0.19 ns/m. Nous avons particulierement etudie les noyaux situes vers les nombres de masse A 50, 90, 140 et 200. Nous comparons ensuite les valeurs experimentales de S{sub 0}, S{sub 1} et R' a differents calculs de modele optique. Un bon accord est obtenu avec un potentiel optique a absorption de surface. (auteur)

  17. Study of the neutron strength function and of the diffusion radius as a function of mass number; Etude de la fonction densite de neutron et du rayon de diffusion en fonction du nombre de masse

    Energy Technology Data Exchange (ETDEWEB)

    Morgenstern, J. [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires

    1968-09-01

    The strength functions S{sub 0} and S{sub 1}, and the scattering length R' are studied. The values of S{sub 0}, S{sub 1} and R' are obtained by shape analysis of the individual resonances observed in total neutron cross-section measurements. These measurements were performed at the Saclay 45 MeV linac by the time of flight method. The best resolution achieved was equal to 0.19 ns/m. We have particularly studied the nuclei around number of mass A = 50, 90, 140 and 200. The experimental values of S{sub 0}, S{sub 1} and R' are compared with optical model calculations. A fairly good agreement is obtained using an optical potential with surface absorption. (author) [French] Nous etudions les fonctions densite S{sub 0} et S{sub 1} ainsi que le rayon de diffusion R'. Les valeurs de S{sub 0}, S{sub 1} et R' sont determinees a partir de l'analyse de forme des resonances individuelles observees lors de la mesure de la section efficace neutronique totale. Cette mesure a ete faite aupres de l'accelerateur lineaire d'electrons de 45 MeV de Saclay par la methode du temps de vol. La meilleure resolution atteinte etait egale a 0.19 ns/m. Nous avons particulierement etudie les noyaux situes vers les nombres de masse A 50, 90, 140 et 200. Nous comparons ensuite les valeurs experimentales de S{sub 0}, S{sub 1} et R' a differents calculs de modele optique. Un bon accord est obtenu avec un potentiel optique a absorption de surface. (auteur)

  18. Neutron Beam Filters

    International Nuclear Information System (INIS)

    Adib, M.

    2011-01-01

    The purpose of filters is to transmit neutrons with selected energy, while remove unwanted ones from the incident neutron beam. This reduces the background, and the number of spurious. The types of commonly used now-a-day neutron filters and their properties are discussed in the present work. There are three major types of neutron filters. The first type is filter of selective thermal neutron. It transmits the main reflected neutrons from a crystal monochromate, while reject the higher order contaminations accompanying the main one. Beams coming from the moderator always contain unwanted radiation like fast neutrons and gamma-rays which contribute to experimental background and to the biological hazard potential. Such filter type is called filter of whole thermal neutron spectrum. The third filter type is it transmits neutrons with energies in the resonance energy range (En . 1 KeV). The main idea of such neutron filter technique is the use of large quantities of a certain material which have the deep interference minima in its total neutron cross-section. By transmitting reactor neutrons through bulk layer of such material, one can obtain the quasimonochromatic neutron lines instead of white reactor spectrum.

  19. Neutron spectrometry and dosimetry with neural networks and Bonner spheres: a study to reduce the spheres number; Espectrometria y dosimetria neutronica con redes neuronales y esferas Bonner: un estudio para reducir el numero de esferas

    Energy Technology Data Exchange (ETDEWEB)

    Espinoza G, J. G.; Martinez B, M. R.; Leon P, A. A.; Hernandez P, C. F.; Castaneda M, V. H.; Solis S, L. O.; Castaneda M, R.; Ortiz R, J. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Av. Ramon Lopez Velarde 801, Col. Centro, 98000 Zacatecas, Zac. (Mexico); Mendez, R. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Laboratorio de Patrones Neutronicos, Av. Complutense 22, 28040 Madrid (Spain); Gallego, E. [Universidad Politecnica de Madrid, Departamento de Ingenieria Nuclear, C. Jose Gutierrez Abascal 2, 28006 Madrid (Spain); De Sousa L, M. A. [Centro de Desenvolvimento da Tecnologia Nuclear / CNEN, Av. Pte. Antonio Carlos 6627, Pampulha, 31270-901 Belo Horizonte, MG (Brazil)

    2016-10-15

    For neutron spectrometry and neutron dosimetry, the Bonner spheres spectrometric system has been the most widely used system, however, the number, size and weight of the spheres composing the system, as well as the need to use a reconstruction code and the long periods of time used to carry out the measurements are some of the disadvantages of this system. For the reconstruction of the spectra, different techniques such as artificial neural networks of reverse propagation have been used. The objective of this work was to reduce the number of Bonner spheres and to use counting speeds in a reverse propagation neural network, optimized by means of the robust design methodology, to reconstruct the neutron spectra. For the design of the neural network we used the neutron spectra of the IAEA and the response matrix of the Bonner spheres with {sup 6}LiI(Eu) detector. The performance of the network was compared; using 7 Bonner spheres against other cases where only 2 and one sphere are used. The network topologies were trained 36 times for each case keeping constant the objective error (1E(-3)), the training algorithm was trains cg and the robust design methodology to determine the best network architectures. With these, the best and worst results were compared. The results obtained using 7 spheres were similar to those with the 5-in sphere, however is still in an information analysis stage. (Author)

  20. Refractive neutron lens

    International Nuclear Information System (INIS)

    Petrov, P.V.; Kolchevsky, N.N.

    2013-01-01

    Model of the refractive neutron lens is proposed. System of N lenses acts as one thin lens with a complex refraction index n*. The maximum number N max of individual lenses for 'thick' neutron lens is calculated. Refractive neutron lens properties (resolution, focal depth) as function of resolution factor F 0 =ρbc/μ and depth of field factor dF 0 =λF 0 =λρbc/μ are calculated. It is shown that micro resolution of the refractive neutron optics is far from the wavelength in size and its open possibilities for progress in refractive neutron optics. (authors)

  1. Relative biological effectiveness (RBE) of fission neutrons and gamma rays at occupational exposure levels: Volume 1, Studies on the genetic effects in mice of 60 equal once-weekly exposures to fission neutrons and gamma rays

    International Nuclear Information System (INIS)

    Grahn, D.; Carnes, B.A.

    1987-10-01

    The relative biological effectiveness (RBE) values for low doses of fission neutrons compared to 60 Co gamma rays were determined with four separate assessments of genetic damage induced in young hybrid male mice. Both radiations were delivered at low dose levels over about one-half the adult lifetime as 60 once-weekly exposures. Genetic damage assessed included both transient and residual injury. The latter is more critical, as residual genetic injury can be transmitted to subsequent generations long after the radiation exposures have ceased. Assays were performed periodically during the 60-week exposure period and at 10 or more weeks after the irradiations had terminated. RBE values, with few exceptions, ranged between 5 and 15 for transient injury and between 25 and 50 for different types of residual genetic injury. The most important form of residual genetic damage in this study was the balanced reciprocal chromosome translocation. These translocations continue to be transmitted throughout reproductive life and can lead to reduced fertility and increased prenatal mortality. The best estimate of the RBE value for translocations was 45 +- 10. Implications and recommendations with regard to the neutron quality factor will be presented conjointly with the findings from the data obtained in this same project on life shortening and on the risks of incidence or death from neoplastic disease. 64 refs., 23 tabs

  2. Neutron energy measurement for practical applications

    Indian Academy of Sciences (India)

    M V Roshan

    2018-02-07

    . Elastic scattering of monoenergetic α-particles from neutron collision enables neutron energy measurement by calculating the amount of deviation from the position where collision takes place. The neutron numbers with ...

  3. Intense fusion neutron sources

    International Nuclear Information System (INIS)

    Kuteev, B. V.; Goncharov, P. R.; Sergeev, V. Yu.; Khripunov, V. I.

    2010-01-01

    The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 10 15 -10 21 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 10 20 neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

  4. Intense fusion neutron sources

    Science.gov (United States)

    Kuteev, B. V.; Goncharov, P. R.; Sergeev, V. Yu.; Khripunov, V. I.

    2010-04-01

    The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 1015-1021 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 1020 neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

  5. Assessment of occupational exposure and contamination by means of airborne particulate matter and biomonitors using k0 instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Menezes, M.A. de B.C.; Pereira Maia, E.C.; Filho, S.S.; Albinati, C.

    2002-01-01

    In order to assess the elemental concentration level in a galvanizing industry and alert for the need to assess the outcome of a long-term exposure, scalp hair and toenail samples were used as bioindicators and the industry environment was evaluated through airborne particulate matter. The elemental concentration results have pointed out a high exposure to pollutant at workplaces and a high elemental concentration in biomonitors suggesting endogenous contamination. The majority of the elements determined in airborne particulate matter were also determined in hair and toenail samples. The results evidence the efficiency of these matrixes as biomonitors and the importance to carry out the airborne particulate matter sampling in parallel to these biomonitors mainly in occupational epidemiological studies. (author)

  6. Polarized neutrons

    International Nuclear Information System (INIS)

    Williams, W.G.

    1988-01-01

    The book on 'polarized neutrons' is intended to inform researchers in condensed matter physics and chemistry of the diversity of scientific problems that can be investigated using polarized neutron beams. The contents include chapters on:- neutron polarizers and instrumentation, polarized neutron scattering, neutron polarization analysis experiments and precessing neutron polarization. (U.K.)

  7. Neutron--neutron logging

    International Nuclear Information System (INIS)

    Allen, L.S.

    1977-01-01

    A borehole logging tool includes a steady-state source of fast neutrons, two epithermal neutron detectors, and two thermal neutron detectors. A count rate meter is connected to each neutron detector. A first ratio detector provides an indication of the porosity of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters connected to the two epithermal neutron detectors. A second ratio detector provides an indication of both porosity and macroscopic absorption cross section of the formation surrounding the borehole by determining the ratio of the outputs of the two count rate meters connected to the two thermal neutron detectors. By comparing the signals of the two ratio detectors, oil bearing zones and salt water bearing zones within the formation being logged can be distinguished and the amount of oil saturation can be determined. 6 claims, 2 figures

  8. Measurement of the average number of prompt neutrons emitted per fission of 235U relative to 252Cf for the energy region 500 eV to 10 MeV

    International Nuclear Information System (INIS)

    Gwin, R.; Spencer, R.R.; Ingle, R.W.; Todd, J.H.; Weaver, H.

    1980-01-01

    The average number of prompt neutrons emitted per fission ν/sub p/-bar(E), was measured for 235 U relative to ν/sub p/-bar for the spontaneous fission of 252 Cf over the neutron energy range from 500 eV to 10 MeV. The samples of 235 U and 252 Cf were contained in fission chambers located in the center of a large liquid scintillator. Fission neutrons were detected by the large liquid scintillator. The present values of ν/sub p/-bar(E) for 235 U are about 0.8% larger than those measured by Boldeman. In earlier work with the present system, it was noted that Boldeman's value of ν/sub p/-bar(E) for thermal energy neutrons was about 0.8% lower than obtained at ORELA. It is suggested that the thickness of the fission foil used in Boldeman's experiment may cause some of the discrepancy between his and the present values of ν/sub p/-bar(E). For the energy region up to 700 keV, the present values of ν/sub p/-bar(E) for 235 U agree, within the uncertainty, with those given in ENDF/B-V. Above 1 MeV the present results for ν/sub p/-bar(E) range about the ENDF/B-V values with differences up to 1.3%. 6 figures, 1 table

  9. A method to calculate fission-fragment yields Y(Z,N) versus proton and neutron number in the Brownian shape-motion model. Application to calculations of U and Pu charge yields

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, Peter [Los Alamos National Laboratory, Theoretical Division, Los Alamos, NM (United States); Ichikawa, Takatoshi [Kyoto University, Yukawa Institute for Theoretical Physics, Kyoto (Japan)

    2015-12-15

    We propose a method to calculate the two-dimensional (2D) fission-fragment yield Y(Z,N) versus both proton and neutron number, with inclusion of odd-even staggering effects in both variables. The approach is to use the Brownian shape-motion on a macroscopic-microscopic potential-energy surface which, for a particular compound system is calculated versus four shape variables: elongation (quadrupole moment Q{sub 2}), neck d, left nascent fragment spheroidal deformation ε{sub f1}, right nascent fragment deformation ε{sub f2} and two asymmetry variables, namely proton and neutron numbers in each of the two fragments. The extension of previous models 1) introduces a method to calculate this generalized potential-energy function and 2) allows the correlated transfer of nucleon pairs in one step, in addition to sequential transfer. In the previous version the potential energy was calculated as a function of Z and N of the compound system and its shape, including the asymmetry of the shape. We outline here how to generalize the model from the ''compound-system'' model to a model where the emerging fragment proton and neutron numbers also enter, over and above the compound system composition. (orig.)

  10. Neutron structural biology

    Energy Technology Data Exchange (ETDEWEB)

    Niimura, Nobuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    Neutron diffraction provides an experimental method of directly locating hydrogen atoms in protein which play important roles in physiological functions. However, there are relatively few examples of neutron crystallography in biology since it takes a lot of time to collect a sufficient number of Bragg reflections due to the low flux of neutrons illuminating the sample. In order to overcome the flux problem, we have successfully developed the neutron IP, where the neutron converter, {sup 6}Li or Gd, was mixed with a photostimulated luminescence material on flexible plastic support. Neutron Laue diffraction 2A data from tetragonal lysozyme were collected for 10 days with neutron imaging plates, and 960 hydrogen atoms in the molecule and 157 bound water molecules were identified. These results explain the proposed hydrolysis mechanism of the sugar by the lysozyme molecule and that lysozyme is less active at pH7.0. (author)

  11. Breaking of the neutron magic number N=20 in 32Mg and 30Ne and its possible relation to the cluster structure

    International Nuclear Information System (INIS)

    Kimura, Masaaki; Horiuchi, Hisashi

    2002-01-01

    The neutron-rich nuclei 32 Mg and 30 Ne are studied using a new version of antisymmetrized molecular dynamics (AMD). Due to the use of a deformed Gaussian as the single particle wave packet, the description of the deformation properties of Mg isotopes is drastically improved, and l·s force is accounted for more largely and sufficiently. After the angular momentum projection, 32 Mg and 30 Ne have deformed ground states, and the experimental data for 32 Mg are reproduced with reasonable accuracy. The deformation of the mean field is found to be essential to describe these nuclei. The ground states of these nuclei have neutron 2p2h structure. In 30 Ne, the cluster-like and the mean-field-like structures coexist. The ground state of 32 Mg has a mean-field-like structure. In the vicinity of the ground state, this nucleus is expected to have excited states with cluster-like structure that possesses the neutron 4p4h configuration. (author)

  12. Breaking of the neutron magic number N=20 in {sup 32}Mg and {sup 30}Ne and its possible relation to the cluster structure

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Masaaki; Horiuchi, Hisashi [Kyoto Univ. (Japan). Dept. of Physics

    2002-01-01

    The neutron-rich nuclei {sup 32}Mg and {sup 30}Ne are studied using a new version of antisymmetrized molecular dynamics (AMD). Due to the use of a deformed Gaussian as the single particle wave packet, the description of the deformation properties of Mg isotopes is drastically improved, and l{center_dot}s force is accounted for more largely and sufficiently. After the angular momentum projection, {sup 32}Mg and {sup 30}Ne have deformed ground states, and the experimental data for {sup 32}Mg are reproduced with reasonable accuracy. The deformation of the mean field is found to be essential to describe these nuclei. The ground states of these nuclei have neutron 2p2h structure. In {sup 30}Ne, the cluster-like and the mean-field-like structures coexist. The ground state of {sup 32}Mg has a mean-field-like structure. In the vicinity of the ground state, this nucleus is expected to have excited states with cluster-like structure that possesses the neutron 4p4h configuration. (author)

  13. Occupational rhinitis.

    Science.gov (United States)

    Petrick, Maria M; Slavin, Raymond G

    2003-05-01

    This article aims to define occupational rhinitis, classify its various causes, review the steps in its diagnosis, and describe its nonpharmacologic and pharmacologic principles of management. Occupational rhinitis frequently coexists with asthma but also occurs alone. Although it does not have the same impact as occupational asthma, occupational rhinitis causes distress, discomfort, and work inefficiency. By concentrating on the patient's workplace, the clinician has an opportunity to practice preventive medicine: to recognize substances in the patient's micro- and macroenvironment that are causing the problems and then to intervene by altering the environment or removing the patient from the environment.

  14. Influence of materials choice on occupational radiation exposure in ITER

    International Nuclear Information System (INIS)

    Forty, C.B.A.; Firth, J.D.; Butterworth, G.J.

    1998-01-01

    In fission reactor plant, the radiation doses associated with inspection and maintenance of the primary cooling circuit account for a substantial fraction of the collective occupational radiation exposure (ORE). Similarly, it is anticipated that much of the ORE occurring during normal operation of ITER will arise from active deposits in the cooling loop. Using a number of calculation steps ranging from neutron activation analysis, mobilisation and transport modelling and Monte Carlo simulation, estimates for the gamma photon flux and radiation dose fields around a typical 'hot-leg' cooling pipe have been made taking SS316, OPTSTAB, MANET-II and F-82H steels as alternative candidate loop materials. (orig.)

  15. Ultracold neutrons

    International Nuclear Information System (INIS)

    Steenstrup, S.

    Briefly surveys recent developments in research work with ultracold neutrons (neutrons of very low velocity, up to 10 m/s at up to 10 -7 eV and 10 -3 K). Slow neutrons can be detected in an ionisation chamber filled with B 10 F 3 . Very slow neutrons can be used for investigations into the dipole moment of neutrons. Neutrons of large wave length have properties similar to those of light. The limit angle for total reflection is governed by the wave length and by the material. Total reflection can be used to filter ultracold neutrons out of the moderator material of a reactor. Total reflection can also be used to store ultracold neutrons but certain problems with storage have not yet been clarified. Slow neutrons can be made to lose speed in a neutron turbine, and come out as ultracold neutrons. A beam of ultracold neutrons could be used in a neutron microscope. (J.S.)

  16. Neutron area monitoring at storage bunkers of density/moisture gauges

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Fuste, M.J. [Grup de Fisica de les Radiacions. Universitat Autonoma de Barcelona (UAB), Edifici Cc, E-08193 Bellaterra (Spain); Amgarou, K., E-mail: khalil.amgarou@uab.ca [Grup de Fisica de les Radiacions. Universitat Autonoma de Barcelona (UAB), Edifici Cc, E-08193 Bellaterra (Spain); Garcia-Orellana, J.; Domingo, C. [Grup de Fisica de les Radiacions. Universitat Autonoma de Barcelona (UAB), Edifici Cc, E-08193 Bellaterra (Spain)

    2010-12-15

    Previous studies remarked the need of performing neutron personal dosimetry, together with gamma dosimetry, when using portable density/moisture gauges that are normally equipped with gamma and neutron sources. The convenience of our Poly-Allyl-Diglycol-Carbonate (PADC) based neutron dosimeter to perform long-term routine survey of all workers involved in the transport, maintenance and usage of these gauges was also corroborated in the past. This complete dosimetric control offers the possibility to quantify simultaneously individual neutron and gamma doses of workers operating such devices, especially in the most frequent cleaning and maintenance (shutter lubrication) operations of the gauges or in emergency situations that may lead to radiological risk of the persons involved. Another aspect to be considered, from the radioprotection point of view, is the optimization of the occupational and public exposure in the storage bunkers of the gauges. In this work, three storage bunkers, located at three different factories of the PAYMA Cotas S.A.U company, have been monitored for three months using several units of our PADC based neutron dosimeter. Special care has been taken to study also offices near the bunkers with high occupancy rates and passage zones, such as toilets and access areas. Results for all monitored points inside and around the three storage bunkers are presented. Neutron doses inside the bunkers could be relatively high depending on the specific conditions (geometry configuration, localization and shielding composition) of the considered bunker and the number of portable gauges stored.

  17. Neutron area monitoring at storage bunkers of density/moisture gauges

    International Nuclear Information System (INIS)

    Garcia-Fuste, M.J.; Amgarou, K.; Garcia-Orellana, J.; Domingo, C.

    2010-01-01

    Previous studies remarked the need of performing neutron personal dosimetry, together with gamma dosimetry, when using portable density/moisture gauges that are normally equipped with gamma and neutron sources. The convenience of our Poly-Allyl-Diglycol-Carbonate (PADC) based neutron dosimeter to perform long-term routine survey of all workers involved in the transport, maintenance and usage of these gauges was also corroborated in the past. This complete dosimetric control offers the possibility to quantify simultaneously individual neutron and gamma doses of workers operating such devices, especially in the most frequent cleaning and maintenance (shutter lubrication) operations of the gauges or in emergency situations that may lead to radiological risk of the persons involved. Another aspect to be considered, from the radioprotection point of view, is the optimization of the occupational and public exposure in the storage bunkers of the gauges. In this work, three storage bunkers, located at three different factories of the PAYMA Cotas S.A.U company, have been monitored for three months using several units of our PADC based neutron dosimeter. Special care has been taken to study also offices near the bunkers with high occupancy rates and passage zones, such as toilets and access areas. Results for all monitored points inside and around the three storage bunkers are presented. Neutron doses inside the bunkers could be relatively high depending on the specific conditions (geometry configuration, localization and shielding composition) of the considered bunker and the number of portable gauges stored.

  18. Neutron activation studies on JET

    International Nuclear Information System (INIS)

    Loughlin, M.J.; Forrest, R.A.; Edwards, J.E.G.

    2001-01-01

    Extensive neutron transport calculations have been performed to determine the neutron spectrum at a number of points throughout the JET torus hall. The model has been bench-marked against a set of foil activation measurements which were activated during an experimental campaign with deuterium/tritium plasmas. The model can predict the neutron activation of the foils on the torus hall walls to within a factor of three for reactions with little sensitivity to thermal neutrons. The use of scandium foils with and without a cadmium thermal neutron absorber was a useful monitor of the thermal neutron flux. Conclusions regarding the usefulness of other foils for benchmarking the calculations are also given

  19. Instrumentation with polarized neutrons

    International Nuclear Information System (INIS)

    Boeni, P.; Muenzer, W.; Ostermann, A.

    2009-01-01

    Neutron scattering with polarization analysis is an indispensable tool for the investigation of novel materials exhibiting electronic, magnetic, and orbital degrees of freedom. In addition, polarized neutrons are necessary for neutron spin precession techniques that path the way to obtain extremely high resolution in space and time. Last but not least, polarized neutrons are being used for fundamental studies as well as very recently for neutron imaging. Many years ago, neutron beam lines were simply adapted for polarized beam applications by adding polarizing elements leading usually to unacceptable losses in neutron intensity. Recently, an increasing number of beam lines are designed such that an optimum use of polarized neutrons is facilitated. In addition, marked progress has been obtained in the technology of 3 He polarizers and the reflectivity of large-m supermirrors. Therefore, if properly designed, only factors of approximately 2-3 in neutron intensity are lost. It is shown that S-benders provide neutron beams with an almost wavelength independent polarization. Using twin cavities, polarized beams with a homogeneous phase space and P>0.99 can be produced without significantly sacrificing intensity. It is argued that elliptic guides, which are coated with large m polarizing supermirrors, provide the highest flux.

  20. Neutron sources and applications

    Energy Technology Data Exchange (ETDEWEB)

    Price, D.L. [ed.] [Argonne National Lab., IL (United States); Rush, J.J. [ed.] [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

    1994-01-01

    Review of Neutron Sources and Applications was held at Oak Brook, Illinois, during September 8--10, 1992. This review involved some 70 national and international experts in different areas of neutron research, sources, and applications. Separate working groups were asked to (1) review the current status of advanced research reactors and spallation sources; and (2) provide an update on scientific, technological, and medical applications, including neutron scattering research in a number of disciplines, isotope production, materials irradiation, and other important uses of neutron sources such as materials analysis and fundamental neutron physics. This report summarizes the findings and conclusions of the different working groups involved in the review, and contains some of the best current expertise on neutron sources and applications.

  1. Neutron sources and applications

    International Nuclear Information System (INIS)

    Price, D.L.; Rush, J.J.

    1994-01-01

    Review of Neutron Sources and Applications was held at Oak Brook, Illinois, during September 8--10, 1992. This review involved some 70 national and international experts in different areas of neutron research, sources, and applications. Separate working groups were asked to (1) review the current status of advanced research reactors and spallation sources; and (2) provide an update on scientific, technological, and medical applications, including neutron scattering research in a number of disciplines, isotope production, materials irradiation, and other important uses of neutron sources such as materials analysis and fundamental neutron physics. This report summarizes the findings and conclusions of the different working groups involved in the review, and contains some of the best current expertise on neutron sources and applications

  2. Neutron scattering

    International Nuclear Information System (INIS)

    1991-02-01

    The annual report on hand gives an overview of the research work carried out in the Laboratory for Neutron Scattering (LNS) of the ETH Zuerich in 1990. Using the method of neutron scattering, it is possible to examine in detail the static and dynamic properties of the condensed material. In accordance with the multidisciplined character of the method, the LNS has for years maintained a system of intensive co-operation with numerous institutes in the areas of biology, chemistry, solid-state physics, crystallography and materials research. In 1990 over 100 scientists from more than 40 research groups both at home and abroad took part in the experiments. It was again a pleasure to see the number of graduate students present, who were studying for a doctorate and who could be introduced into the neutron scattering during their stay at the LNS and thus were in the position to touch on central ways of looking at a problem in their dissertation using this modern experimental method of solid-state research. In addition to the numerous and interesting ways of formulating the questions to explain the structure, nowadays the scientific programme increasingly includes particularly topical studies in connection with high temperature-supraconductors and materials research

  3. Neutron energy measurement for practical applications

    Science.gov (United States)

    Roshan, M. V.; Sadeghi, H.; Ghasabian, M.; Mazandarani, A.

    2018-03-01

    Industrial demand for neutrons constrains careful energy measurements. Elastic scattering of monoenergetic α -particles from neutron collision enables neutron energy measurement by calculating the amount of deviation from the position where collision takes place. The neutron numbers with specific energy is obtained by counting the number of α -particles in the corresponding location on the charged particle detector. Monte Carlo simulation and COMSOL Multiphysics5.2 are used to account for one-to-one collision of neutrons with α -particles.

  4. Neutron Research in HANARO

    International Nuclear Information System (INIS)

    Kim, Hark Rho

    2005-01-01

    HANARO (High-flux Advanced Neutron Application Reactor), which was designed and constructed by indigenous technology, is a world-class multi-purpose research reactor with a design thermal power of 30 MW, providing high neutron flux for various applications in Korea. HANARO has been operated since its first criticality in February 1995, and is now successfully utilized in such areas as neutron beam research, fuel and materials tests, radioisotopes and radiopharmaceuticals production, neutron activation analysis, and neutron transmutation doping, etc. A number of experimental facilities have been developed and installed since the beginning of reactor operation, and R and D activities for installing more facilities are actively under progress. Three flux traps in the core (CT, IR1, IR2), providing a high fast neutron flux, can be used for materials and fuel irradiation tests. They are also proper for production of high specific activity radioisotopes. Four vertical holes in the outer core region, abundant in epithermal neutrons, are used for fuel or material tests and radioisotope production. In the heavy water reflector region, 25 vertical holes with high quality thermal neutrons are located for radioisotope production, neutron activation analysis, neutron transmutation doping and cold neutron source installation. The two largest holes named NTD1 and NTD2 are for neutron transmutation doping, CNS for the cold neutron source installation, and LH for the irradiation of large targets. The high resolution powder diffractometer (HRPD) became operational in 1998, followed by the four circle diffractometer (FCD) in 1999, the residual stress instrument (RSI) in 2000, and the small angle neutron spectrometer (SANS) in 2001, respectively. HRPD and SANS became the most popular instruments these days, attracting wide range of users from academia, institutes and industries. We have made a lot of efforts during the last 10 years to develop some key components such as

  5. Occupational health in Brazil.

    Science.gov (United States)

    Bedrikow, B; Algranti, E; Buschinelli, J T; Morrone, L C

    1997-01-01

    Brazil is a recently industrialised country with marked contrasts in social and economic development. The availability of public/private services in its different regions also varies. Health indicators follow these trends. Occupational health is a vast new field, as in other developing countries. Occupational medicine is a required subject in graduation courses for physicians. Specialisation courses for university graduated professionals have more than 700 hours of lectures and train occupational health physicians, safety engineers and nursing staff. At the technical level, there are courses with up to 1300 hours for the training of safety inspectors. Until 1986 about 19,000 occupational health physicians, 18,000 safety engineers and 51,000 safety inspectors had been officially registered. Although in its infancy, postgraduation has attracted professionals at university level, through residence programmes as well as masters and doctors degrees, whereby at least a hundred good-quality research studies have been produced so far. Occupational health activities are controlled by law. Undertakings with higher risks and larger number of employees are required to hire specialised technical staff. In 1995 the Ministry of Labour demanded programmes of medical control of occupational health (PCMSO) for every worker as well as a programme of prevention of environmental hazards (PPRA). This was considered as a positive measure for the improvement of working conditions and health at work. Physicians specialising in occupational medicine are the professionals more often hired by the enterprises. Reference centres (CRSTs) for workers' health are connected to the State or City Health Secretariat primary health care units. They exist in more populated areas and are accepted by workers as the best way to accomplish the diagnosis of occupational diseases. There is important participation by the trade unions in the management of these reference centres. For 30 years now employers

  6. NEUTRON AND PHOTON DOSE MAPPING OF A DD NEUTRON GENERATOR.

    Science.gov (United States)

    Metwally, Walid A; Taqatqa, Osama A; Ballaith, Mohammed M; Chen, Allan X; Piestrup, Melvin A

    2017-11-01

    Neutron generators are an excellent tool that can be effectively utilized in educational institutions for applications such as neutron activation analysis, neutron radiography, and profiling and irradiation effects. For safety purposes, it is imperative that appropriate measures are taken in order to minimize the radiation dose from such devices to the operators, students and the public. This work presents the simulation and measurement results for the neutron and photon dose rates in the vicinity of the neutron generator installed at the University of Sharjah. A very good agreement is found between the simulated and measured dose rates. All of the public dose constraints were found to be met. The occupational dose constraint was also met after imposing a 200 cm no entry zone around the generator room. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. Occupational Health

    Science.gov (United States)

    Occupational health problems occur at work or because of the kind of work you do. These problems can include ... by exposure to radiation Exposure to germs in health care settings Good job safety and prevention practices ...

  8. Occupational Cancer

    Science.gov (United States)

    ... November 3, 2015 Content source: National Institute for Occupational Safety and Health Division of Surveillance, Hazard Evaluations, and Field Studies ... Fear Act OIG 1600 Clifton Road Atlanta , GA 30329-4027 ...

  9. Occupational health

    CERN Document Server

    Fingret, Dr Ann

    2013-01-01

    Offers a comprehensive view of health and safety issues at work. An invaluable resource for managers, personnel professionals and occupational health practitioners. Recommended by the Institute of Personnel Management.

  10. Occupational cancer

    International Nuclear Information System (INIS)

    Nelson, N.

    1987-01-01

    Cancer resulting from occupational exposure is now receiving major attention, focusing on identification, regulation, and control of cancer-causing agents. Such cancer can result from exposure to chemicals and ionizing and nonionizing radiation. Extended exposure (often years) and an extended latent period of perhaps decades may intervene before tumor appearance. Although the actual extent of occupational cancer is in debate, estimates have ranged from 4 to 15 per cent of all cancer

  11. Occupational health

    OpenAIRE

    Coosemans, R.

    1997-01-01

    Health at work and healthy work environments are among the most valuable assets of individuals, communities and countries. Nowadays, new broader approach is promoted, recognizing the fact that occupational health is a key, but not a unique element of workers’ health. Workers health is a public health approach to resolving the health problems of working populations including all determinants of health recognized as targets of risk management. It focuses on primary prevention of occupational an...

  12. Neutron reflectometry

    International Nuclear Information System (INIS)

    Van Well, A.A.

    1999-01-01

    Neutron research where reflection, refraction, and interference play an essential role is generally referred to as 'neutron optics'. The neutron wavelength, the scattering length density and the magnetic properties of the material determine the critical angle for total reflection. The theoretical background of neutron reflection, experimental methods and the interpretation of reflection data are presented. (K.A.)

  13. Introduction to neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Lattimer, James M. [Dept. of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States)

    2015-02-24

    Neutron stars contain the densest form of matter in the present universe. General relativity and causality set important constraints to their compactness. In addition, analytic GR solutions are useful in understanding the relationships that exist among the maximum mass, radii, moments of inertia, and tidal Love numbers of neutron stars, all of which are accessible to observation. Some of these relations are independent of the underlying dense matter equation of state, while others are very sensitive to the equation of state. Recent observations of neutron stars from pulsar timing, quiescent X-ray emission from binaries, and Type I X-ray bursts can set important constraints on the structure of neutron stars and the underlying equation of state. In addition, measurements of thermal radiation from neutron stars has uncovered the possible existence of neutron and proton superfluidity/superconductivity in the core of a neutron star, as well as offering powerful evidence that typical neutron stars have significant crusts. These observations impose constraints on the existence of strange quark matter stars, and limit the possibility that abundant deconfined quark matter or hyperons exist in the cores of neutron stars.

  14. Neutrons in biology

    International Nuclear Information System (INIS)

    Funahashi, Satoru; Niimura, Nobuo.

    1993-01-01

    The start of JRR-3M in 1990 was a great epoch to the neutron scattering research in Japan. Abundant neutron beam generated by the JRR-3M made it possible to widen the research field of neutron scattering in Japan. In the early days of neutron scattering, biological materials were too difficult object to be studied by neutrons not only because of their complexity but also because of the strong incoherent scattering by hydrogen. However, the remarkable development of the recent neutron scattering and its related sciences, as well as the availability of higher flux, has made the biological materials one of the most attractive subjects to be studied by neutrons. In early September 1992, an intensive workshop titled 'Neutrons in Biology' was held in Hitachi City by making use of the opportunity of the 4th International Conference on Biophysics and Synchrotron Radiation (BSR92) held in Tsukuba. The workshop was organized by volunteers who are eager to develop the researches in this field in Japan. Numbers of outstanding neutron scattering biologists from U.S., Europe and Asian countries met together and enthusiastic discussions were held all day long. The editors believe that the presentations at the workshop were so invaluable that it is absolutely adequate to put them on record as an issue of JAERI-M and to make them available for scientists to refer to in order to further promote the research in the future. (author)

  15. Polycapillary neutron lenses

    International Nuclear Information System (INIS)

    Mildner, D.F.R.

    1997-01-01

    The principle of multiple mirror reflection from smooth surfaces at small grazing angles enables the transport and guiding of high intensity slow neutron beams to locations of low background for neutron scattering and absorption experiments and to provide facilities for multiple instruments. Curved guides have been widely used at cold neutron facilities to remove the unwanted radiation (fast neutrons and gamma rays) from the beam without the use of filters. A typical guide has transverse dimensions of 50 mm and, with a radius of curvature of 1 km, transmits wavelengths longer than 5 A. Much tighter curves requires narrower transverse dimensions, otherwise there is little transmission. Typical neutron benders have a number of slots with transverse dimensions of ∼5 mm. Based on the same principle but using a different technology, recent developments in glass polycapillary fibers have produced miniature versions of neutron guides. Fibers with many thousands of channels having sizes of ∼ 10 μm enable beams of long wavelength neutrons (λ > 4 A) to be transmitted efficiently in a radius of curvature as small as a fraction of 1 m. A large collection of these miniature versions of neutron guides can be used to bend the neutron trajectories such that the incident beam can be focused. (author)

  16. [News on occupational contact dermatitis].

    Science.gov (United States)

    Crépy, Marie-Noëlle; Bensefa-Colas, Lynda

    2014-03-01

    Contact dermatitis--irritant contact dermatitis, allergic contact dermatitis and protein contact dermatitis--are the most common occupational skin diseases, most often localized to the hands. Contact urticaria is rarer The main occupational irritants are wet work, detergents and disinfectants, cutting oils, and solvents. The main occupational allergens are rubber additives, metals (chromium, nickel, cobalt), plastics (epoxy resins, acrylic), biocides and plants. Diagnosis is based on clinical examination, medical history and allergy testing. For a number of irritating or sensitizing agents, irritant or allergic dermatitis can be notified as occupational diseases. The two main prevention measures are reducing skin contact with irritants and complete avoidance of skin contact with offending allergens.

  17. Nucleus Z=126 with magic neutron number N=184 may be related to the measured Maruhn–Greiner maximum at A/2=155 from compound nuclei at low energy nuclear reactions

    Energy Technology Data Exchange (ETDEWEB)

    Prelas, M.A. [University of Missouri, Columbia, MO (United States); Hora, H. [University of New South Wales, Sydney (Australia); Miley, G.H. [University of Illinois, Urbana-Champaign (United States)

    2014-07-04

    Evaluation of nuclear binding energies from theory close to available measurements of a very high number of superheavy elements (SHE) based on α-decay energies Q{sub α}, arrived at a closing shell with a significant neutron number 184. Within the option of several discussed magic numbers for protons of around 120, Bagge's numbers 126 and 184 fit well and are supported by the element generation measurements by low energy nuclear reactions (LENR) discovered in deuterium loaded host metals. These measurements were showing a Maruhn–Greiner maximum from fission of compound nuclei in an excited state with double magic numbers for mutual confirmation. - Highlights: • Use of Bagge procedure confirmed that Z=126 and N=184 are proper magic numbers. • Elements are generated by low energy nuclear reactions in deuterium loaded metal. • Postulated from measured distribution that a compound nucleus {sup 310}X{sub 126} was formed. • Formation of 164 deuterons in Bose–Einstein state clusters with 2 pm spacing.

  18. Nucleus Z=126 with magic neutron number N=184 may be related to the measured Maruhn–Greiner maximum at A/2=155 from compound nuclei at low energy nuclear reactions

    International Nuclear Information System (INIS)

    Prelas, M.A.; Hora, H.; Miley, G.H.

    2014-01-01

    Evaluation of nuclear binding energies from theory close to available measurements of a very high number of superheavy elements (SHE) based on α-decay energies Q α , arrived at a closing shell with a significant neutron number 184. Within the option of several discussed magic numbers for protons of around 120, Bagge's numbers 126 and 184 fit well and are supported by the element generation measurements by low energy nuclear reactions (LENR) discovered in deuterium loaded host metals. These measurements were showing a Maruhn–Greiner maximum from fission of compound nuclei in an excited state with double magic numbers for mutual confirmation. - Highlights: • Use of Bagge procedure confirmed that Z=126 and N=184 are proper magic numbers. • Elements are generated by low energy nuclear reactions in deuterium loaded metal. • Postulated from measured distribution that a compound nucleus 310 X 126 was formed. • Formation of 164 deuterons in Bose–Einstein state clusters with 2 pm spacing

  19. 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...

  20. Diffuse scattering of neutrons

    International Nuclear Information System (INIS)

    Novion, C.H. de.

    1981-02-01

    The use of neutron scattering to study atomic disorder in metals and alloys is described. The diffuse elastic scattering of neutrons by a perfect crystal lattice leads to a diffraction spectrum with only Bragg spreads. the existence of disorder in the crystal results in intensity and position modifications to these spreads, and above all, to the appearance of a low intensity scatter between Bragg peaks. The elastic scattering of neutrons is treated in this text, i.e. by measuring the number of scattered neutrons having the same energy as the incident neutrons. Such measurements yield information on the static disorder in the crystal and time average fluctuations in composition and atomic displacements [fr

  1. BR2 reactor neutron beams

    International Nuclear Information System (INIS)

    Neve de Mevergnies, M.

    1977-01-01

    The use of reactor neutron beams is becoming increasingly more widespread for the study of some properties of condensed matter. It is mainly due to the unique properties of the ''thermal'' neutrons as regards wavelength, energy, magnetic moment and overall favorable ratio of scattering to absorption cross-sections. Besides these fundamental reasons, the impetus for using neutrons is also due to the existence of powerful research reactors (such as BR2) built mainly for nuclear engineering programs, but where a number of intense neutron beams are available at marginal cost. A brief introduction to the production of suitable neutron beams from a reactor is given. (author)

  2. Occupational injuries in Bahrain.

    Science.gov (United States)

    al-Arrayed, A; Hamza, A

    1995-10-01

    A study was conducted to show the problem of occupational injuries in Bahrain and try to highlight some solutions that may help to prevent or reduce workplace hazards. The data for occupational injuries between 1988 to 1991 from the social insurance records were reviewed and analysed. The data were summarized, grouped and tabulated according to age, sex, nationality, work place, type of injuries, cause and site of injury. Data were analysed statistically, frequencies were computed and results represented graphically. The study shows that there was a decline in the number of injuries in 1990 and 1991 due to a slow-down of economic activities in general in the Arabian Gulf region during the Gulf War. It also shows that Asian workers are at a high risk of occupational injuries.

  3. Neutron Dosimetry

    International Nuclear Information System (INIS)

    Vanhavere, F.

    2001-01-01

    The objective of SCK-CEN's R and D programme on neutron dosimetry is to improve the determination of neutron doses by studying neutron spectra, neutron dosemeters and shielding adaptations. In 2000, R and D focused on the contiued investigation of the bubble detectors type BD-PND and BDT, in particular their sensitivity and temperature dependence; the updating of SCK-CEN's criticality dosemeter, the investigation of the characteristics of new thermoluminescent materials and their use in neutron dosemetry; and the investigation of neutron shielding

  4. Neutron Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Vanhavere, F

    2001-04-01

    The objective of SCK-CEN's R and D programme on neutron dosimetry is to improve the determination of neutron doses by studying neutron spectra, neutron dosemeters and shielding adaptations. In 2000, R and D focused on the contiued investigation of the bubble detectors type BD-PND and BDT, in particular their sensitivity and temperature dependence; the updating of SCK-CEN's criticality dosemeter, the investigation of the characteristics of new thermoluminescent materials and their use in neutron dosemetry; and the investigation of neutron shielding.

  5. Synovectomy by Neutron capture

    International Nuclear Information System (INIS)

    Vega C, H.R.; Torres M, C.

    1998-01-01

    The Synovectomy by Neutron capture has as purpose the treatment of the rheumatoid arthritis, illness which at present does not have a definitive curing. This therapy requires a neutron source for irradiating the articulation affected. The energy spectra and the intensity of these neutrons are fundamental since these neutrons induce nuclear reactions of capture with Boron-10 inside the articulation and the freely energy of these reactions is transferred at the productive tissue of synovial liquid, annihilating it. In this work it is presented the neutron spectra results obtained with moderator packings of spherical geometry which contains in its center a Pu 239 Be source. The calculations were realized through Monte Carlo method. The moderators assayed were light water, heavy water base and the both combination of them. The spectra obtained, the average energy, the neutron total number by neutron emitted by source, the thermal neutron percentage and the dose equivalent allow us to suggest that the moderator packing more adequate is what has a light water thickness 0.5 cm (radius 2 cm) and 24.5 cm heavy water (radius 26.5 cm). (Author)

  6. Radiation safety of soil moisture neutron probes

    International Nuclear Information System (INIS)

    Oresegun, M.O.

    2000-01-01

    The neutron probe measures sub-surface moisture in soil and other materials by means of high energy neutrons and a slow (thermal) neutron detector. Exposure to radiation, including neutrons, especially at high doses, can cause detrimental health effects. In order to achieve operational radiation safety, there must be compliance with protection and safety standards. The design and manufacture of commercially available neutron moisture gauges are such that risks to the health of the user have been greatly reduced. The major concern is radiation escape from the soil during measurement, especially under dry conditions and when the radius of influence is large. With appropriate work practices as well as good design and manufacture of gauges, recorded occupational doses have been well below recommended annual limits. It can be concluded that the use of neutron gauges poses not only acceptable health and safety risks but, in fact, the risks are negligible. Neutron gauges should not be classified as posing high potential health hazards. (author)

  7. Particle physics with cold neutrons

    International Nuclear Information System (INIS)

    Dubbers, D.

    1991-01-01

    Slow neutrons are used in a large number of experiments to study the physics of particles and their fundamental interactions. Some of these experiments search for manifestations of ''new physics'' like baryon- or lepton-number nonconservation, time reversal nonconservation, new particles, right-handed currents, nonzero neutron charge, nonlinear terms in the Schrodinger equation, exotic e + e - states, and others. Other slow neutron experiments test the present Standard Model. The parity nonconserving weak neutron-nucleon interaction is studied in a variety of experiments. Free neutron beta decay gives precise values for the weak vector and axialvector coupling constants, which allow precise tests of basic symmetries like the conservation of the weak vector current, the unitarity of the weak quark mixing matrix, SU(3) flavour symmetry, and right-handed currents. Neutron beta decay data are further needed to calculate weak cross-sections, for applications, in big bang cosmology, in astrophysics, in solar physics and the solar neutrino problem, and in such mundane things as neutrino detection efficiencies in neutrino oscillation or proton decay experiments. Neutron-nucleon, neutron-nucleus and neutron-electron scattering lengths are determined in high precision experiments, which use methods like neutron interferometry or neutron gravity spectrometry. The experiments give information on quantities like the neutron charge radius or the neutron electric polarizability. Precision measurements of other fundamental constants lead to a better, model-independent value of the fine structure constant. Finally, the fundamental experiments on quantum mechanics, like spinor 4π -rotation, Berry's phase, dressed neutrons, Aharanov - Casher effect, or gravitational effects on the neutron's phase will be briefly discussed. (author)

  8. Neutron induced radiation damage

    International Nuclear Information System (INIS)

    Williams, M.M.R.

    1977-01-01

    We derive a general expression for the number of displaced atoms of type j caused by a primary knock-on of type i. The Kinchin-Pease model is used, but considerably generalised to allow for realistic atomic potentials. Two cases are considered in detail: the single particle problem causing a cascade and the neutron initiated problem which leads to multiple subcascades. Numerical results have been obtained for a variety of scattering laws. An important conclusion is that neutron initiated damage is much more severe than atom-initiated damage and leads to the number of displaced atoms being a factor of (A+1) 2 /4A larger than the single primary knock-on theory predicts. A is the ratio of the atomic mass to the neutron mass. The importance of this result to the theory of neutron sputtering is explained. (orig.) [de

  9. Study of neutron shell structure of even-even 40-56Ca isotopes by the dispersive optical model

    International Nuclear Information System (INIS)

    Bespalova, O.V.; Boboshin, I.N.; Varlamov, V.V.; Ermakova, T.A.; Ishkhanov, B.S.; Romanovskij, E.A.; Spasskaya, T.I.; Timokhina, T.P.

    2005-01-01

    The single-particle energies and occupation probabilities of the bound neutron states in 40,42,44,46,48 Ca isotopes were obtained by the joint evaluation of the stripping and pick-up reaction data. The results were analyzed by the dispersive optical model and a good agreement was achieved. The dispersive optical potential was extrapolated to unstable 50,52,54,56 Ca nuclei. The calculated single-particle energies of the bound neutron states in unstable Ca isotopes were compared with the nuclear shell-model calculations, which predicted new magic number N = 34 for nuclei with Z = 20 [ru

  10. Neutron radiography

    International Nuclear Information System (INIS)

    Hrdlicka, Z.

    1977-01-01

    Neutron radiography is a radiographic method using a neutron beam of a defined geometry. The neutron source usually consists of a research reactor, a specialized neutron radiography reactor or the 252 Cf radioisotope source. There are two types of the neutron radiography display system, viz., a system producing neutron radiography images by a photographic process or a system allowing a visual display, eg., using a television monitor. The method can be used wherever X-ray radiography is used except applications in the radiography of humans. The neutron radiography unit at UJV uses the WWR-S reactor as the neutron source and both types of the above mentioned display system. (J.P.)

  11. Pulsed spallation Neutron Sources

    International Nuclear Information System (INIS)

    Carpenter, J.M.

    1994-01-01

    This paper reviews the early history of pulsed spallation neutron source development at Argonne and provides an overview of existing sources world wide. A number of proposals for machines more powerful than currently exist are under development, which are briefly described. The author reviews the status of the Intense Pulsed Neutron Source, its instrumentation, and its user program, and provides a few examples of applications in fundamental condensed matter physics, materials science and technology

  12. Pulsed spallation neutron sources

    International Nuclear Information System (INIS)

    Carpenter, J.M.

    1996-01-01

    This paper reviews the early history of pulsed spallation neutron source development ar Argonne and provides an overview of existing sources world wide. A number of proposals for machines more powerful than currently exist are under development, which are briefly described. The author reviews the status of the Intense Pulsed Neutron Source, its instrumentation, and its user program, and provide a few examples of applications in fundamental condensed matter physics, materials science and technology

  13. The neutron

    International Nuclear Information System (INIS)

    Kredov, B.M.

    1979-01-01

    The history of the neutron is displayed on the basis of contributions by scientists who produced outstanding results in neutron research (part 1), of summarizing discoveries and theories which led to the discovery of the neutron and the resulting development of nuclear physics (part 2), and of fundamental papers written by Rutherford, Chadwick, Iwanenko, and others (appendix). Of interest to physicists, historians, and students

  14. Neutron techniques

    International Nuclear Information System (INIS)

    Charlton, J.S.

    1986-01-01

    The way in which neutrons interact with matter such as slowing-down, diffusion, neutron absorption and moderation are described. The use of neutron techniques in industry, in moisture gages, level and interface measurements, the detection of blockages, boron analysis in ore feedstock and industrial radiography are discussed. (author)

  15. Dynamical theory of neutron diffraction

    International Nuclear Information System (INIS)

    Sears, V.F.

    1978-01-01

    We present a review of the dynamical theory of neutron diffraction by macroscopic bodies which provides the theoretical basis for the study of neutron optics. We consider both the theory of dispersion, in which it is shown that the coherent wave in the medium satisfies a macroscopic one-body Schroedinger equation, and the theory of reflection, refraction, and diffraction in which the above equation is solved for a number of special cases of interest. The theory is illustrated with the help of experimental results obtained over the past 10 years by a number of new techniques such as neutron gravity refractometry. Pendelloesung interference, and neutron interferometry. (author)

  16. Occupational hazards

    OpenAIRE

    Paz-Fuchs, Amir; Ronen, Yaël

    2012-01-01

    This article provides an analysis and a critique of the law governing the employment relationship between Israeli employers and Palestinian employees in industries operating in the West Bank. \\ud \\ud Through an analysis of Israeli jurisprudence it highlights the intersection among different areas of law: choice of law, public international law (in particular the law of occupation), and labor law. The article explores the tensions that this intersection creates: first, between the importance t...

  17. Neutron flux monitor

    International Nuclear Information System (INIS)

    Oda, Naotaka.

    1993-01-01

    The device of the present invention greatly saves an analog processing section such as an analog filter and an analog processing circuit. That is, the device of the present invention comprises (1) a neutron flux detection means for detecting neutron fluxed in the reactor, (2) a digital filter means for dividing signals corresponding to the detected neutron fluxes into predetermined frequency band regions, (3) a calculation processing means for applying a calculation processing corresponding to the frequency band regions to the neutron flux detection signals divided by the digital filter means. With such a constitution, since the neutron detection signals are processed by the digital filter means, the accuracy is improved and the change for the property of the filter is facilitated. Further, when a neutron flux level is obtained, a calculation processing corresponding to the frequency band region can be conducted without the analog processing circuit. Accordingly, maintenance and accuracy are improved by greatly decreasing the number of parts. Further, since problems inherent to the analog circuit are solved, neutron fluxes are monitored at high reliability. (I.S.)

  18. Neutrons at COSY

    International Nuclear Information System (INIS)

    Filges, D.; Freiesleben, H.

    1988-05-01

    For many years neutrons were considered important both as a useful probe in nuclear physics research and as an initiator and catalyst for fission, fusion and other applications. As a result knowledge about neutrons, especially below 20 MeV, received organized world-wide attention. Research with neutrons at medium energies, say 50 MeV to several GeV, has not consistently received attention and no systematic evaluations exist. But there is a large and considerable interest today because medium energy neutrons are very important in basic science and technology. The aim of this workshop was to provide an overview of the present status and the research which should be carried out in this field in future and which kind of experiments should be performed at the COSY facility: State-of-the-art about medium energy neutron experiments and existing facilities; planned experiments; needs for experiments doing research with neutrons at COSY (detectors, accelerator requirements, time structure etc.); what will be a first experiment to measure neutrons at COSY. The interest in this workshop is documented by a large number of participants. Copies of the viewgraphs of the talks are provided. (orig./HP)

  19. Neutron diffraction studies of high-T/sub c/ superconductors

    International Nuclear Information System (INIS)

    Jorgensen, J.D.

    1988-03-01

    Neutron powder diffraction techniques have been used extensively for the study of high-T/sub c/ oxide superconductors because of the need to locate oxygen atoms and accurately determine the oxygen site occupancies, and the difficulty in obtaining single crystals. For example, in the case of YBa 2 Cu 3 O/sub 7-δ/, neutron powder diffraction and Rietveld structural refinement were used to obtain the first complete structural information. Subsequent experiments focussed on determining the relationship of superconducting properties to the number and distribution of oxygen vacancies on the Cu-O sublattice with measurements being done on samples in thermodynamic equilibrium, at high temperature in controlled oxygen atmospheres, and on metastable, oxygen-deficient samples produced by quenching. Neutron powder diffraction has also been used to determine the structures of compounds in which the properties have been modified by substitution on the Y, Ba, or Cu sites. This paper briefly reviews some of the neutron powder diffraction results in these areas. 17 refs

  20. Role of neutrons in the fusion of nuclei

    International Nuclear Information System (INIS)

    Zagrebaev, V. I.; Samarin, V. V.

    2007-01-01

    The problem of a quantum-mechanical description of a near-barrier fusion of heavy nuclei under conditions of a strong coupling of their relative motion to neutron degrees of freedom is studied. New mutually complementing efficient models employing the multidimensional time-dependent Schroedinger equation and methods for numerically solving the problems in question within these models are proposed. This makes it possible to study the evolution of wave functions for outer neutrons and to calculate nucleon transfer probabilities and occupation numbers for quasimolecular states over the entire energy range, including that of deep-subbarrier energies. It is shown that the valence-neutron wave functions extend over the volumes of both colliding nuclei before their surfaces come into contact and even before these nuclei overcome the Coulomb barrier (collectivization of outer nucleons). This gives rise to a substantial neutron-transfer effect on the fusion of nuclei and, in particular, to a sizable increase in the probability of subbarrier fusion for specific combinations of nuclei

  1. Neutron flux monitoring device

    International Nuclear Information System (INIS)

    Shimazu, Yoichiro.

    1995-01-01

    In a neutron flux monitoring device, there are disposed a neutron flux measuring means for outputting signals in accordance with the intensity of neutron fluxes, a calculation means for calculating a self power density spectrum at a frequency band suitable to an object to be measured based on the output of the neutron flux measuring means, an alarm set value generation means for outputting an alarm set value as a comparative reference, and an alarm judging means for comparing the alarm set value with the outputted value of the calculation means to judge requirement of generating an alarm and generate an alarm in accordance with the result of the judgement. Namely, the time-series of neutron flux signals is put to fourier transformation for a predetermined period of time by the calculation means, and from each of square sums for real number component and imaginary number component for each of the frequencies, a self power density spectrum in the frequency band suitable to the object to be measured is calculated. Then, when the set reference value is exceeded, an alarm is generated. This can reliably prevent generation of erroneous alarm due to neutron flux noises and can accurately generate an alarm at an appropriate time. (N.H.)

  2. Neutron measuring device

    International Nuclear Information System (INIS)

    Hatayama, Akiyoshi; Seki, Eiji; Kita, Yoshio; Nishitani, Takeo.

    1993-01-01

    The device of the present invention concerns measurement for neutrons in a tokamak type thermonuclear device and it can measure total amount of generated neutrons accurately throughout the operation period even if an error is caused in counted values by plasma disruption. That is, the device comprises (1) a means for detecting presence or absence of occurrence of plasma disruption and the time for the initiation of the occurrence, (2) a first data processing means for processing detection signals, (3) a means for detecting neutrons generated in plasmas and (4) a second data processing means for calculating integrated values for the number of neutrons generated from the start to the completion of electric discharge when no disruption occurs and calculating integrated values for the number of generated neutrons from the start of electric discharge to the time at the initiation of occurrence of the disruption when disruption is present. In the thus constituted device, even if an error is caused by frequent occurrence of plasma disruption, total time integrated amount of neutrons generated in the plasmas can be measured accurately. (I.S.)

  3. Structure of Insulin: Results of joint neutron and X-ray refinement

    Energy Technology Data Exchange (ETDEWEB)

    Wlodawer, A; Savage, H; Dodson, G

    1989-02-01

    Neutron diffraction data for porcine 2Zn insulin were collected to 2.2 A resolution from a single crystal deuterated by slow exchange of mother liquor. A joint neutron/X-ray restrained-least-squares refinement was undertaken using the neutron data, as well as the 1.5 A resolution X-ray data collected previously. The final R factors were 0.182 for the X-ray data and 0.191 for the neutron data. Resulting atomic coordinates were compared with the initial X-ray model, showing a total r.m.s. shift of 0.36 A for the protein and 0.6 A for the solvent. Protonation of a number of individual amino acids was investigated by analysis of the neutron maps. No D atoms were found between the carboxylates of Glu B13 which make an intermolecular contact, suggesting nonbonded interaction rather than the predicted hydrogen bond. Amide hydrogen exchange was investigated in a refinement of their atomic occupancies. Regions of unexchanged amide groups were found in the center of the B helices. The results of this study emphasize the limited amount of information available in neutron diffraction studies of proteins at resolution lower than 2 A.

  4. The neutron computer tomography

    International Nuclear Information System (INIS)

    Matsumoto, G.; Krata, S.

    1983-01-01

    The method of computer tomography (CT) was applied for neutrons instead of X-rays. The neutron radiography image of samples was scanned by microphotometer to get the transmission data. This process was so time-consuming that the number of incident angles to samples could not be increased. The transmission data was processed by FACOM computer and CT image was gained. In the experiment at the Japan Research Reactor No. 4 at Tokai-mura with 18 projection angles, the resolution of paraffin in the aluminum block was less than 0.8 mm. In the experiment at Van de Graaf accelerator of Nagoya University, this same resolution was 1.2 mm because of the angle distribution of neutron beam. This experiment is the preliminary one, the facility which utilizes neutron television and video-recorder will be necessary for the next stage. (Auth.)

  5. Neutron radiography

    International Nuclear Information System (INIS)

    Hiraoka, Eiichi

    1988-01-01

    The thermal neutron absorption coefficient is essentially different from the X-ray absorption coefficient. Each substance has a characteristic absorption coefficient regardless of its density. Neutron deams have the following features: (1) neutrons are not transmitted efficiently by low molecular weight substances, (2) they are transmitted efficiently by heavy metals, and (3) the transmittance differs among isotopes. Thus, neutron beams are suitable for cheking for foreign matters in heavy metals and testing of composites consisting of both heavy and light materials. A neutron source generates fast neutrons, which should be converted into thermal neutrons by reducing their energy. Major neutron souces include nuclear reactors, radioisotopes and particle accelerators. Photographic films and television systems are mainly used to observe neutron transmission images. Computers are employed for image processing, computerized tomography and three-dimensional analysis. The major applications of neutron radiography include inspection of neclear fuel; evaluation of material for airplane; observation of fuel in the engine and oil in the hydraulic systems in airplanes; testing of composite materials; etc. (Nogami, K.)

  6. Analysis of records of external occupational dose records in Brazil

    International Nuclear Information System (INIS)

    Mauricio, Claudia L.P.; Silva, Herica L.R. da; Silva, Claudio Ribeiro da

    2014-01-01

    Brazil, a continental country, with actually more than 150,000 workers under individual monitoring for ionizing radiation, has implemented in 1987 a centralized system for storage of external occupational dose. This database has been improved over the years and is now a web-based information system called Brazilian External Occupational Dose Management Database System - GDOSE. This paper presents an overview of the Brazilian external occupational dose over the years. The estimated annual average effective dose shows a decrease from 2.4 mSv in 1987 to about 0.6 mSv, having been a marked reduction from 1987 to 1990. Analyzing by type of controlled practice, one sees that the medical and dental radiology is the area with the largest number of users of individual monitors (70%); followed by education practices (8%) and the industrial radiography (7%). Additionally to photon whole body monitoring; neutron monitors are used in maintenance (36%), reactor (30%) and education (27%); and extremity monitors, in education (27%), nuclear medicine (22%) and radiology (19%). In terms of collective dose, the highest values are also found in conventional radiology, but the highest average dose values are those of interventional radiology. Nuclear medicine, R and D and radiotherapy also have average annual effective dose higher than 1 mSv. However, there is some very high dose values registered in GDOSE that give false information. This should be better analyzed in the future. Annual doses above 500 are certainly not realistic. (author)

  7. Occupation: nurse; occupational hazard: radiation

    International Nuclear Information System (INIS)

    Nickson, K.

    1984-01-01

    The work of the occupational health nurses at the Pickering Generating Station is described. A staff of two nurses teach first aid and safety, practice an emergency plan, and monitor personnel for minimum health standards for radiation workers. Special attention is paid to problems which might be aggravated by radiation, such as skin complaints, respiratory diseases, emotional stability, or phobias regarding heights, plastic suits, or radiation itself. Procedures used in treating contaminated personnel are outlined

  8. Occupation: nurse; occupational hazard: radiation

    Energy Technology Data Exchange (ETDEWEB)

    Nickson, K

    1984-03-01

    The work of the occupational health nurses at the Pickering Generating Station is described. A staff of two nurses teach first aid and safety, practice an emergency plan, and monitor personnel for minimum health standards for radiation workers. Special attention is paid to problems which might be aggravated by radiation, such as skin complaints, respiratory diseases, emotional stability, or phobias regarding heights, plastic suits, or radiation itself. Procedures used in treating contaminated personnel are outlined.

  9. Fusion neutronics

    CERN Document Server

    Wu, Yican

    2017-01-01

    This book provides a systematic and comprehensive introduction to fusion neutronics, covering all key topics from the fundamental theories and methodologies, as well as a wide range of fusion system designs and experiments. It is the first-ever book focusing on the subject of fusion neutronics research. Compared with other nuclear devices such as fission reactors and accelerators, fusion systems are normally characterized by their complex geometry and nuclear physics, which entail new challenges for neutronics such as complicated modeling, deep penetration, low simulation efficiency, multi-physics coupling, etc. The book focuses on the neutronics characteristics of fusion systems and introduces a series of theories and methodologies that were developed to address the challenges of fusion neutronics, and which have since been widely applied all over the world. Further, it introduces readers to neutronics design’s unique principles and procedures, experimental methodologies and technologies for fusion systems...

  10. Neutron spectometers

    International Nuclear Information System (INIS)

    Poortmans, F.

    1977-01-01

    Experimental work in the field of low-energy neutron physics can be subdivided into two classes: 1)Study of the decay process of the compound-nucleus state as for example the study of the capture gamma rays and of the neutron induced fission process; 2)Study of the reaction mechanism, mainly by measuring the reaction cross-sections and resonance parameters. These neutron cross-sections and resonance parameters are also important data required for many technological applications especially for reactor development programmes. In general, the second class of experiments impose other requirements on the neutron spectrometer than the first class. In most cases, a better neutron energy resolution and a broader neutron energy range are required for the study of the reaction mechanism than for the study of various aspects of the decay process. (author)

  11. Occupational physiology

    CERN Document Server

    Toomingas, Allan; Tornqvist, Ewa Wigaeus

    2011-01-01

    In a clear and accessible presentation, Occupational Physiology focuses on important issues in the modern working world. Exploring major public health problems-such as musculoskeletal disorders and stress-this book explains connections between work, well-being, and health based on up-to-date research in the field. It provides useful methods for risk assessment and guidelines on arranging a good working life from the perspective of the working individual, the company, and society as a whole.The book focuses on common, stressful situations in different professions. Reviewing bodily demands and r

  12. Neutron exposure

    International Nuclear Information System (INIS)

    Prillinger, G.; Konynenburg, R.A. van

    1998-01-01

    As a result of the popularity of the Agencies report 'Neutron Irradiation Embrittlement of Reactor Pressure Vessel Steels' of 1975, it was decided that another report on this broad subject would be of use. In this report, background and contemporary views on specially identified areas of the subject are considered as self-contained chapters, written by experts. In chapter 6, LWR-PV neutron transport calculations and dosimetry methods and how they are combined to evaluate the neutron exposure of the steel of pressure vessels are discussed. An effort to correlate neutron exposure parameters with damage is made

  13. Atmospheric neutrons

    International Nuclear Information System (INIS)

    Preszler, A.M.; Moon, S.; White, R.S.

    1976-01-01

    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 J 2 /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

  14. 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.

  15. Neutron cross sections for fusion

    International Nuclear Information System (INIS)

    Haight, R.C.

    1979-10-01

    First generation fusion reactors will most likely be based on the 3 H(d,n) 4 He reaction, which produces 14-MeV neutrons. In these reactors, both the number of neutrons and the average neutron energy will be significantly higher than for fission reactors of the same power. Accurate neutron cross section data are therefore of great importance. They are needed in present conceptual designs to calculate neutron transport, energy deposition, nuclear transmutation including tritium breeding and activation, and radiation damage. They are also needed for the interpretation of radiation damage experiments, some of which use neutrons up to 40 MeV. In addition, certain diagnostic measurements of plasma experiments require nuclear cross sections. The quality of currently available data for these applications will be reviewed and current experimental programs will be outlined. The utility of nuclear models to provide these data also will be discussed. 65 references

  16. Recent development in magnetic neutron scattering studies

    International Nuclear Information System (INIS)

    Endoh, Yasuo

    1993-01-01

    Neutron scattering results contain many new concepts in modern magnetism. We review here the most recent neutron magnetic scattering studies from so called '214' copper oxide lamellar materials, because a number of important developments in magnetism are condensed in this novel subject. We show that neutron scattering has played crucial role in our understanding of modern magnetism. (author)

  17. Cryogenic refrigeration for cold neutron sources

    International Nuclear Information System (INIS)

    Gistau-Baguer, Guy

    1998-01-01

    Neutron moderation by means of a fluid at cryogenic temperature is a very interesting way to obtain cold neutrons. Today, a number of nuclear research reactors are using this technology. This paper deals with thermodynamics and technology which are used for cooling Cold Neutron Sources

  18. Neutron scattering in Australia

    International Nuclear Information System (INIS)

    Knott, R.B.

    1994-01-01

    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

  19. 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.

  20. Measuring neutron spectra in radiotherapy using the nested neutron spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Maglieri, Robert, E-mail: robert.maglieri@mail.mcgill.ca; Evans, Michael; Seuntjens, Jan; Kildea, John [Medical Physics Unit, McGill University, Montreal, Quebec H4A 3J1 (Canada); Licea, Angel [Canadian Nuclear Safety Commission, Ottawa, Ontario K1P 5S9 (Canada)

    2015-11-15

    Purpose: Out-of-field neutron doses resulting from photonuclear interactions in the head of a linear accelerator pose an iatrogenic risk to patients and an occupational risk to personnel during radiotherapy. To quantify neutron production, in-room measurements have traditionally been carried out using Bonner sphere systems (BSS) with activation foils and TLDs. In this work, a recently developed active detector, the nested neutron spectrometer (NNS), was tested in radiotherapy bunkers. Methods: The NNS is designed for easy handling and is more practical than the traditional BSS. Operated in current-mode, the problem of pulse pileup due to high dose-rates is overcome by measuring current, similar to an ionization chamber. In a bunker housing a Varian Clinac 21EX, the performance of the NNS was evaluated in terms of reproducibility, linearity, and dose-rate effects. Using a custom maximum-likelihood expectation–maximization algorithm, measured neutron spectra at various locations inside the bunker were then compared to Monte Carlo simulations of an identical setup. In terms of dose, neutron ambient dose equivalents were calculated from the measured spectra and compared to bubble detector neutron dose equivalent measurements. Results: The NNS-measured spectra for neutrons at various locations in a treatment room were found to be consistent with expectations for both relative shape and absolute magnitude. Neutron fluence-rate decreased with distance from the source and the shape of the spectrum changed from a dominant fast neutron peak near the Linac head to a dominant thermal neutron peak in the moderating conditions of the maze. Monte Carlo data and NNS-measured spectra agreed within 30% at all locations except in the maze where the deviation was a maximum of 40%. Neutron ambient dose equivalents calculated from the authors’ measured spectra were consistent (one standard deviation) with bubble detector measurements in the treatment room. Conclusions: The NNS may

  1. 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

  2. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1994-12-31

    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

  3. A Safety and Health Guide for Vocational Educators. Incorporating Requirements of the Occupational Safety and Health Act of 1970, Relevant Pennsylvania Requirements with Particular Emphasis for Those Concerned with Cooperative Education and Work Study Programs. Volume 15. Number 1.

    Science.gov (United States)

    Wahl, Ray

    Intended as a guide for vocational educators to incorporate the requirements of the Occupational Safety and Health Act (1970) and the requirements of various Pennsylvania safety and health regulations with their cooperative vocational programs, the first chapter of this document presents the legal implications of these safety and health…

  4. Neutronic reactor

    International Nuclear Information System (INIS)

    Wende, C.W.J.

    1976-01-01

    A safety rod for a nuclear reactor has an inner end portion having a gamma absorption coefficient and neutron capture cross section approximately equal to those of the adjacent shield, a central portion containing materials of high neutron capture cross section and an outer end portion having a gamma absorption coefficient at least equal to that of the adjacent shield

  5. Neutron holography

    International Nuclear Information System (INIS)

    Beynon, T.D.

    1986-01-01

    the paper concerns neutron holography, which allows an image to be constructed of the surfaces, as well as the interiors, of objects. The technique of neutron holography and its applications are described. Present and future use of the method is briefly outlined. (U.K.)

  6. Occupational applications of ultraviolet radiation

    International Nuclear Information System (INIS)

    Eriksen, P.

    1987-01-01

    A large population of workers are exposed to ultraviolet radiation in various occupational environments which often necessitates protection. Since ultraviolet radiation may create other environmental problems an occupational hazard- and protection evaluation can be complicated. Threshold Limit Values adopted by the American Conference of Governmental Industrial Hygienists (ACGIH) on ultraviolet radiation are used in most countries as guidelines for risk assessment and control measures. This review addresses the levels of ultraviolet radiation met in occupational environments, its measurement and evaluation, and discusses different protection methods. Ultraviolet lasers are beginning to find their way into industrial processes but are still limited in number and they will not be covered here. Emphasis is on broad band incoherent radiation in high risk environments such as welding, and on the evaluation of protective eyewear, see-through curtains and plastics. Other occupational risks associated with the emission of ultraviolet radiation are discussed

  7. Occupation and cancer in Britain.

    Science.gov (United States)

    Rushton, L; Bagga, S; Bevan, R; Brown, T P; Cherrie, J W; Holmes, P; Fortunato, L; Slack, R; Van Tongeren, M; Young, C; Hutchings, S J

    2010-04-27

    Prioritising control measures for occupationally related cancers should be evidence based. We estimated the current burden of cancer in Britain attributable to past occupational exposures for International Agency for Research on Cancer (IARC) group 1 (established) and 2A (probable) carcinogens. We calculated attributable fractions and numbers for cancer mortality and incidence using risk estimates from the literature and national data sources to estimate proportions exposed. 5.3% (8019) cancer deaths were attributable to occupation in 2005 (men, 8.2% (6362); women, 2.3% (1657)). Attributable incidence estimates are 13 679 (4.0%) cancer registrations (men, 10 063 (5.7%); women, 3616 (2.2%)). Occupational attributable fractions are over 2% for mesothelioma, sinonasal, lung, nasopharynx, breast, non-melanoma skin cancer, bladder, oesophagus, soft tissue sarcoma, larynx and stomach cancers. Asbestos, shift work, mineral oils, solar radiation, silica, diesel engine exhaust, coal tars and pitches, occupation as a painter or welder, dioxins, environmental tobacco smoke, radon, tetrachloroethylene, arsenic and strong inorganic mists each contribute 100 or more registrations. Industries and occupations with high cancer registrations include construction, metal working, personal and household services, mining, land transport, printing/publishing, retail/hotels/restaurants, public administration/defence, farming and several manufacturing sectors. 56% of cancer registrations in men are attributable to work in the construction industry (mainly mesotheliomas, lung, stomach, bladder and non-melanoma skin cancers) and 54% of cancer registrations in women are attributable to shift work (breast cancer). This project is the first to quantify in detail the burden of cancer and mortality due to occupation specifically for Britain. It highlights the impact of occupational exposures, together with the occupational circumstances and industrial areas where exposures to carcinogenic agents

  8. Neutron source

    International Nuclear Information System (INIS)

    Cason, J.L. Jr.; Shaw, C.B.

    1975-01-01

    A neutron source which is particularly useful for neutron radiography consists of a vessel containing a moderating media of relatively low moderating ratio, a flux trap including a moderating media of relatively high moderating ratio at the center of the vessel, a shell of depleted uranium dioxide surrounding the moderating media of relatively high moderating ratio, a plurality of guide tubes each containing a movable source of neutrons surrounding the flux trap, a neutron shield surrounding one part of each guide tube, and at least one collimator extending from the flux trap to the exterior of the neutron source. The shell of depleted uranium dioxide has a window provided with depleted uranium dioxide shutters for each collimator. Reflectors are provided above and below the flux trap and on the guide tubes away from the flux trap

  9. Neutron transport

    International Nuclear Information System (INIS)

    Berthoud, Georges; Ducros, Gerard; Feron, Damien; Guerin, Yannick; Latge, Christian; Limoge, Yves; Santarini, Gerard; Seiler, Jean-Marie; Vernaz, Etienne; Coste-Delclaux, Mireille; M'Backe Diop, Cheikh; Nicolas, Anne; Andrieux, Catherine; Archier, Pascal; Baudron, Anne-Marie; Bernard, David; Biaise, Patrick; Blanc-Tranchant, Patrick; Bonin, Bernard; Bouland, Olivier; Bourganel, Stephane; Calvin, Christophe; Chiron, Maurice; Damian, Frederic; Dumonteil, Eric; Fausser, Clement; Fougeras, Philippe; Gabriel, Franck; Gagnier, Emmanuel; Gallo, Daniele; Hudelot, Jean-Pascal; Hugot, Francois-Xavier; Dat Huynh, Tan; Jouanne, Cedric; Lautard, Jean-Jacques; Laye, Frederic; Lee, Yi-Kang; Lenain, Richard; Leray, Sylvie; Litaize, Olivier; Magnaud, Christine; Malvagi, Fausto; Mijuin, Dominique; Mounier, Claude; Naury, Sylvie; Nicolas, Anne; Noguere, Gilles; Palau, Jean-Marc; Le Pallec, Jean-Charles; Peneliau, Yannick; Petit, Odile; Poinot-Salanon, Christine; Raepsaet, Xavier; Reuss, Paul; Richebois, Edwige; Roque, Benedicte; Royer, Eric; Saint-Jean, Cyrille de; Santamarina, Alain; Serot, Olivier; Soldevila, Michel; Tommasi, Jean; Trama, Jean-Christophe; Tsilanizara, Aime; Behar, Christophe; Provitina, Olivier; Lecomte, Michael; Forestier, Alain; Bender, Alexandra; Parisot, Jean-Francois; Finot, Pierre

    2013-10-01

    This bibliographical note presents a reference book which addresses the study of neutron transport in matter, the study of conditions for a chain reaction and the study of modifications of matter composition due to nuclear reactions. This book presents the main nuclear data, their measurement, assessment and processing, and the spallation. It proposes an overview of methods applied for the study of neutron transport: basic equations and their derived forms, deterministic methods and Monte Carlo method of resolution of the Boltzmann equation, methods of resolution of generalized Bateman equations, methods of time resolution of space kinetics coupled equations. It presents the main calculation codes, discusses the qualification and experimental aspects, and gives an overview of neutron transport applications: neutron transport calculation of reactors, neutron transport coupled with other disciplines, physics of fuel cycle, criticality

  10. Prevalence of occupational disease

    Energy Technology Data Exchange (ETDEWEB)

    Newhouse, M.L.

    1976-12-01

    When discussing the prevalence of occupational disease, both the prescribed diseases and the diseases where occupation has an important etiological component should be considered. Available statistics indicate that there has been a substantial improvement in the control of important prescribed diseases such as lead poisoning and pneumoconiosis. In the United Kingdom in 1900 there were 1000 cases of lead poisoning with 38 fatalities. This number decreased to 49 cases in 1956 when the number again increased due to a change from clinical diagnosis to diagnosis on biochemical evidence. The number of cases of coal workers' pneumoconiosis has declined since the 1950s but the number of coal miners has also been reduced by more than /sup 1///sub 3/. Industrial dermatitis is still a considerable problem. Vibration induced white fingers was mentioned as a disease with a very large occupational component but which for a variety of reasons is not prescribed for industrial injury benefit. Illnesses due to injuries to the back, to sciatica, disc disease or lumbago cause a very large amount of sickness and are often associated with heavy manual labor particularly if an awkward posture has to be adopted for the job. The average absence after a back injury in the London Docks was 61 days. Chronic bronchitis is the biggest single cause of sickness absence. Many studies have shown that the etiology is multifactorial but that hard physical work and a dusty environment in the work place are important adverse factors. Improved control of the working environment and methods of work may influence the development of chronic disease in the older worker.

  11. DOE 2012 Occupational Radiation Exposure October 2013

    Energy Technology Data Exchange (ETDEWEB)

    Podonsky, Glenn S. [US Dept. of Energy, Washington, DC (United States). Office of Health, Safety and Security

    2012-02-02

    The U.S. Department of Energy (DOE) Office of Analysis within the Office of Health, Safety and Security (HSS) publishes the annual DOE Occupational Radiation Exposure Report to provide an overview of the status of radiation protection practices at DOE (including the National Nuclear Security Administration [NNSA]). The DOE 2012 Occupational Radiation Exposure Report provides an evaluation of DOE-wide performance regarding compliance with Title 10, Code of Federal Regulations (C.F.R.), Part 835, Occupational Radiation Protection dose limits and as low as reasonably achievable (ALARA) process requirements. In addition, the report provides data to DOE organizations responsible for developing policies for protection of individuals from the adverse health effects of radiation. The report provides a summary and an analysis of occupational radiation exposure information from the monitoring of individuals involved in DOE activities. Over the past 5-year period, the occupational radiation exposure information is analyzed in terms of aggregate data, dose to individuals, and dose by site. As an indicator of the overall amount of radiation dose received during the conduct of operations at DOE, the report includes information on collective total effective dose (TED). The TED is comprised of the effective dose (ED) from external sources, which includes neutron and photon radiation, and the internal committed effective dose (CED), which results from the intake of radioactive material into the body. The collective ED from photon exposure decreased by 23% between 2011 and 2012, while the neutron dose increased by 5%. The internal dose components of the collective TED decreased by 7%. Over the past 5-year period, 99.99% of the individuals receiving measurable TED have received doses below the 2 roentgen equivalent in man (rems) (20 millisievert [mSv]) TED administrative control level (ACL), which is well below the DOE regulatory limit of 5 rems (50 mSv) TED annually. The

  12. Feasibility of sealed D-T neutron generator as neutron source for liver BNCT and its beam shaping assembly.

    Science.gov (United States)

    Liu, Zheng; Li, Gang; Liu, Linmao

    2014-04-01

    This paper involves the feasibility of boron neutron capture therapy (BNCT) for liver tumor with four sealed neutron generators as neutron source. Two generators are placed on each side of the liver. The high energy of these emitted neutrons should be reduced by designing a beam shaping assembly (BSA) to make them useable for BNCT. However, the neutron flux decreases as neutrons pass through different materials of BSA. Therefore, it is essential to find ways to increase the neutron flux. In this paper, the feasibility of using low enrichment uranium as a neutron multiplier is investigated to increase the number of neutrons emitted from D-T neutron generators. The neutron spectrum related to our system has a proper epithermal flux, and the fast and thermal neutron fluxes comply with the IAEA recommended values. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Occupational diseases in Poland, 2012

    Directory of Open Access Journals (Sweden)

    Urszula Wilczyńska

    2013-06-01

    Full Text Available Background: The aim of the paper was to present basic statistical data on occupational diseases diagnosed in 2012. Material and Methods: The work was based on the data from "Occupational Disease Reporting Forms" received by the Central Register of Occupational Diseases in 2012. The data comprised information on nosologic units, gender and age of patients, duration of occupational exposure, sections of the national economy and voivodeships. The incidence was specified in terms of the number of cases in relation to paid employees or to employed people. Results: The number of occupational diseases accounted for 2402 cases. The incidence rate was 23 cases per 100 000 paid employees. In spite of the general decline in the number of cases, the incidence of infectious and parasitic diseases increased by 8.6%. The highest incidence was noted for infectious and parasitic diseases (6.8/100 000, pneumoconioses (5.5/100 000, hearing loss (2.1/100 000, diseases of: the peripheral nervous system (2/100 000, voice disorders (1.9/100 000 and the musculo-skeletal system pathologies (1.1/100 000. The pathologies specified above accounted in total for 84% of all occupational diseases. The industrial sectors of the national economy characterized by the highest incidence included mining and quarrying (288.3/100 000 and manufacturing (27.8/100 000. The highest incidence was recorded in the Silesian (46.2/100 000 and the lowest in the Opolskie (4.2/100 000 voivodeships. Conclusions: The downward trend in the incidence of occupational diseases continues. Different incidence of voice disorders among teachers in individual provinces suggests that uniform preventive, diagnostic and certification standards are missing. Med Pr 2013;64(3:317–326

  14. Neutron therapy

    International Nuclear Information System (INIS)

    Riesler, Rudi

    1995-01-01

    Standard radiotherapy uses Xrays or electrons which have low LET (linear energy transfer); in contrast, particles such as neutrons with high LET have different radiobiological responses. In the late 1960s, clinical trials by Mary Catterall at the Hammersmith Hospital in London indicated that fast neutron radiation had clinical advantages for certain malignant tumours. Following these early clinical trials, several cyclotron facilities were built in the 1980s for fast neutron therapy, for example at the University of Washington, Seattle, and at UCLA. Most of these newer machines use extracted cyclotron proton beams in the range 42 to 66 MeV with beam intensities of 15 to 60 microamps. The proton beams are transported to dedicated therapy rooms, where neutrons are produced from beryllium targets. Second-generation clinical trials showed that accurate neutron beam delivery to the tumour site is more critical than for photon therapy. In order to achieve precise beam geometries, the extracted proton beams have to be transported through a gantry which can rotate around the patient and deliver beams from any angle; also the neutron beam outline (''field shape'') must be adjusted to extremely irregular shapes using a flexible collimation system. A therapy procedure has to be appropriately organized, with physicians, radiotherapists, nurses, medical physicists and other staff in attendance; other specialized equipment, such as CT or MRI scanners and radiation simulators must be made available. Neutron therapy is usually performed only in radiation oncology departments of major medical centres

  15. Neutron radiography

    International Nuclear Information System (INIS)

    Alaa eldin, M.T.

    2011-01-01

    The digital processing of the neutron radiography images gives the possibility for data quantification. In this case an exact relation between the measured neutron attenuation and the real macroscopic attenuation coefficient for every point of the sample is required. The assumption that the attenuation of the neutron beam through the sample is exponential is valid only in an ideal case where a monochromatic beam, non scattering sample and non background contribution are assumed. In the real case these conditions are not fulfilled and in dependence on the sample material we have more or less deviation from the exponential attenuation law. Because of the high scattering cross-sections of hydrogen (σs=80.26 barn) for thermal neutrons, the problem with the scattered neutrons at quantitative radiography investigations of hydrogenous materials (as PE, Oil, H 2 O, etc) is not trivial. For these strong scattering materials the neutron beam attenuation is no longer exponential and a dependence of the macroscopic attenuation coefficient on the material thickness and on the distance between the sample and the detector appears. When quantitative radiography (2 D) or tomography investigations (3 D) are performed, some image correction procedures for a description of the scattering effect are required. This thesis presents a method that can be used to enhance the neutron radiography image for objects with high scattering materials like hydrogen, carbon and other light materials. This method uses the Monte Carlo code, MCNP5, to simulate the neutron radiography process and get the flux distribution for each pixel of the image and determine the scattered neutrons distribution that causes the image blur and then subtract it from the initial image to improve its quality.

  16. Slow neutron scattering experiments

    International Nuclear Information System (INIS)

    Moon, R.M.

    1985-01-01

    Neutron scattering is a versatile technique that has been successfully applied to condensed-matter physics, biology, polymer science, chemistry, and materials science. The United States lost its leadership role in this field to Western Europe about 10 years ago. Recently, a modest investment in the United States in new facilities and a positive attitude on the part of the national laboratories toward outside users have resulted in a dramatic increase in the number of US scientists involved in neutron scattering research. Plans are being made for investments in new and improved facilities that could return the leadership role to the United States. 23 references, 4 figures, 3 tables

  17. Neutronics codes

    International Nuclear Information System (INIS)

    Buckel, G.

    1983-01-01

    The objectives are the development, testing and cultivation of reliable, efficient and user-optimized neutron-physical calculation methods and conformity with users' requirements concerning design of power reactors, planning and analysis of experiments necessary for their protection as well as research on physical key problems. A short outline of available computing programmes for the following objectives is given: - Provision of macroscopic group constants, - Calculation of neutron flux distribution in transport theory and diffusion approximation, - Evaluation of neutron flux-distribution, - Execution of disturbance calculations for the determination reactivity coefficients, and - graphical representation of results. (orig./RW) [de

  18. Nuclear threshold effects and neutron strength function

    International Nuclear Information System (INIS)

    Hategan, Cornel; Comisel, Horia

    2003-01-01

    One proves that a Nuclear Threshold Effect is dependent, via Neutron Strength Function, on Spectroscopy of Ancestral Neutron Threshold State. The magnitude of the Nuclear Threshold Effect is proportional to the Neutron Strength Function. Evidence for relation of Nuclear Threshold Effects to Neutron Strength Functions is obtained from Isotopic Threshold Effect and Deuteron Stripping Threshold Anomaly. The empirical and computational analysis of the Isotopic Threshold Effect and of the Deuteron Stripping Threshold Anomaly demonstrate their close relationship to Neutron Strength Functions. It was established that the Nuclear Threshold Effects depend, in addition to genuine Nuclear Reaction Mechanisms, on Spectroscopy of (Ancestral) Neutron Threshold State. The magnitude of the effect is proportional to the Neutron Strength Function, in their dependence on mass number. This result constitutes also a proof that the origins of these threshold effects are Neutron Single Particle States at zero energy. (author)

  19. Neutron physics entering the 21st century

    International Nuclear Information System (INIS)

    Aksenov, V.L.

    2000-01-01

    The objectives of present-day neutron physics are neutron-aided investigations of fundamental interactions and symmetries, high excited states of nuclei, crystalline and magnetic structures, dynamic excitations in solids and liquids over a wide range of energies. The state-of-art and perspectives of the solution of most topical and principle problems of neutron physics are analyzed. The main conclusion is that neutron physics provides rich information for nuclear particle physics, physics of nucleus, condensed matter physics, chemistry, biology, materials science, and earth sciences. In the next century, however, new higher flux neutron sources must be created. By the year 2010 the number of nuclear reactors used for physical research will reduce to 10-15 reactors over the world. Trends in the development of neutron sources are analyzed. The possibilities of leading neutron research centers in the world are considered and most promising projects of neutron sources are discussed. (author)

  20. Catalogue of neutron spectra

    International Nuclear Information System (INIS)

    Buxerolle, M.; Massoutie, M.; Kurdjian, J.

    1987-09-01

    Neutron dosimetry problems have arisen as a result of developments in the applications of nuclear energy. The largest number of possible irradiation situations has been collected: they are presented in the form of a compilation of 44 neutron spectra. Diagrams show the variations of energy fluence and energy fluence weighted by the dose equivalent/fluence conversion factor, with the logarithm of the corresponding energy. The equivalent dose distributions are presented as percentages for the following energy bins: 0.01 eV/0.5 eV/50 keV/1 MeV/5 MeV/15 MeV. The dose equivalent, the mean energy and the effective energy for the dose equivalent for 1 neutron cm -2 are also given [fr

  1. Multidisk neutron velocity selectors

    International Nuclear Information System (INIS)

    Hammouda, B.

    1992-01-01

    Helical multidisk velocity selectors used for neutron scattering applications have been analyzed and tested experimentally. Design and performance considerations are discussed along with simple explanation of the basic concept. A simple progression is used for the inter-disk spacing in the 'Rosta' design. Ray tracing computer investigations are presented in order to assess the 'coverage' (how many absorbing layers are stacked along the path of 'wrong' wavelength neutrons) and the relative number of neutrons absorbed in each disk (and therefore the relative amount of gamma radiation emitted from each disk). We discuss whether a multidisk velocity selector can be operated in the 'reverse' configuration (i.e. the selector is turned by 180 0 around a vertical axis with the rotor spun in the reverse direction). Experimental tests and calibration of a multidisk selector are reported together with evidence that a multidisk selector can be operated in the 'reverse' configuration. (orig.)

  2. Some properties of zero power neutron noise in a time-varying medium with delayed neutrons

    International Nuclear Information System (INIS)

    Kitamura, Y.; Pal, L.; Pazsit, I.; Yamamoto, A.; Yamane, Y.

    2008-01-01

    The temporal evolution of the distribution of the number of neutrons in a time-varying multiplying system, producing only prompt neutrons, was treated recently with the master equation technique by some of the present authors. Such a treatment gives account of both the so-called zero power reactor noise and the power reactor noise simultaneously. In particular, the first two moments of the neutron number, as well as the concept of criticality for time-varying systems, were investigated and discussed. The present paper extends these investigations to the case when delayed neutrons are also taken into account. Due to the complexity of the description, only the expectation of the neutron number is calculated. The concept of criticality of a time-varying system is also generalized to systems with delayed neutrons. The temporal behaviour of the expectation of the number of neutrons and its asymptotic properties are displayed and discussed

  3. Neutron reflectometry

    DEFF Research Database (Denmark)

    Klösgen-Buchkremer, Beate Maria

    2014-01-01

    of desired information. In the course, an introduction into the method and an overview on selected instruments at large scale facilities will be presented. Examples will be given that illustrate the potential of the method, mostly based on organic films. Results from the investigation of layered films......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...... films or films with magnetic properties. The reason is the peculiar property of neutron light since the mass of a neutron is close to the one of a proton, and since it bears a magnetic moment. The optical properties of matter, when interacting with neutrons, are described by a refractive index...

  4. Neutron scattering

    International Nuclear Information System (INIS)

    Furrer, A.

    1993-01-01

    This report contains the text of 16 lectures given at the Summer School and the report on a panel discussion entitled ''the relative merits and complementarities of x-rays, synchrotron radiation, steady- and pulsed neutron sources''. figs., tabs., refs

  5. An Analysis of the Payroll Clerking Occupation.

    Science.gov (United States)

    Peal, Sharyn; Rose, Virginia

    The general purpose of the occupational analysis is to provide workable, basic information dealing with the many and varied duties performed in the payroll clerk occupation. The document opens with a brief introduction followed by a job description. The bulk of the document is presented in table form. Ten duties are broken down into a number of…

  6. Occupational Sequences: Auto Engines 1. AT 121.

    Science.gov (United States)

    Korb, A. W.; And Others

    In an attempt to individualize an automotive course, the Vocational-Technical Division of Northern Montana College has developed Occupational Sequences for an engine rebuilding course. Occupational Sequences, a learning or teaching aid, is an analysis of numbered operations involved in engine rebuilding. Job sheets, included in the book, provide a…

  7. Human rights in occupational therapy education: A step towards a more occupationally just global society.

    Science.gov (United States)

    Crawford, Emma; Aplin, Tammy; Rodger, Sylvia

    2017-04-01

    Education on human rights will place occupational therapists in a strong position to address societal inequities that limit occupational engagement for many client groups. The imminent changes to the Minimum Standard for the Education of Occupational Therapists engender efforts towards social change and will require university-level human rights education. This education might enhance the profession's influence on disadvantaging social structures in order to effect social change. To contribute to the evidence base for social change education in occupational therapy, this research aims to understand the knowledge, skills, confidence and learning experiences of occupational therapy students who completed a human rights course. Final year occupational therapy students responded to questionnaires which included listing human rights, a human rights scale measuring knowledge and confidence for working towards human rights, and open questions. Numbers of rights listed, knowledge scores and confidence scores were calculated. Responses to the open questions were thematically analysed. After completing a human rights course, students had good knowledge and moderate confidence to work with human rights. Three themes were identified including 'learning about human rights', 'learning about structural, societal and global perspectives on occupational engagement' and 'learning how occupational therapists can work with groups, communities and populations: becoming articulate and empowered'. Human rights education fosters the development of occupational therapists who are skilled, knowledgeable, confident and empowered to address occupational injustices, according to these research findings. To develop a more occupationally just global society, education that considers iniquitous social structures and human rights is necessary. © 2016 Occupational Therapy Australia.

  8. Neutron storage

    International Nuclear Information System (INIS)

    Strelkov, A.V.

    2004-01-01

    The report is devoted to neutron storage (NS) and describes the history of experiments on the NS development. Great attention is paid to ultracold neutron (UCN) storage. The experiments on the UCN generation, transport, spectroscopy, storage and detection are described. Experiments on searching the UCN electric-dipole moment and electric charge are continued. Possible using of UCN for studying the nanoparticles is discussed [ru

  9. Neutron radiography

    International Nuclear Information System (INIS)

    Bayon, G.

    1989-01-01

    Neutronography or neutron radiography, a non-destructive test method which is similar in its principle to conventional X-ray photography, presently occupies a marginal position among non-destructive test methods (NDT) (no source of suitable performance or cost). Neutron radiography associated with the ORPHEE reactor permits industrial testing; it can very quickly meet a cost requirement comparable to that of conventional test methods. In 1988, 2500 parts were tested on this unit [fr

  10. Neutron source multiplication method

    International Nuclear Information System (INIS)

    Clayton, E.D.

    1985-01-01

    Extensive use has been made of neutron source multiplication in thousands of measurements of critical masses and configurations and in subcritical neutron-multiplication measurements in situ that provide data for criticality prevention and control in nuclear materials operations. There is continuing interest in developing reliable methods for monitoring the reactivity, or k/sub eff/, of plant operations, but the required measurements are difficult to carry out and interpret on the far subcritical configurations usually encountered. The relationship between neutron multiplication and reactivity is briefly discussed and data presented to illustrate problems associated with the absolute measurement of neutron multiplication and reactivity in subcritical systems. A number of curves of inverse multiplication have been selected from a variety of experiments showing variations observed in multiplication during the course of critical and subcritical experiments where different methods of reactivity addition were used, with different neutron source detector position locations. Concern is raised regarding the meaning and interpretation of k/sub eff/ as might be measured in a far subcritical system because of the modal effects and spectrum differences that exist between the subcritical and critical systems. Because of this, the calculation of k/sub eff/ identical with unity for the critical assembly, although necessary, may not be sufficient to assure safety margins in calculations pertaining to far subcritical systems. Further study is needed on the interpretation and meaning of k/sub eff/ in the far subcritical system

  11. Fast neutron dosimetry

    International Nuclear Information System (INIS)

    DeLuca, P.M. Jr.; Pearson, D.W.

    1991-01-01

    During 1988--1990 the magnetic resonance dosimetry project was completed, as were the 250 MeV proton shielding measurements. The first cellular experiment using human cells in vitro at the 1 GeV electron storage ring was also accomplished. More detail may be found in DOE Report number-sign DOE/EV/60417-002 and the open literature cited in the individual progress subsections. We report Kinetic Energy Released in Matter (KERMA), factor measurements in several elements of critical importance to neutron radiation therapy and radiation protection for space habitation and exploration for neutron energies below 30 MeV. The results of this effort provide the only direct measurements of the oxygen and magnesium kerma factors above 20 MeV neutron energy, and the only measurements of the iron kerma factor above 15 MeV. They provide data of immediate relevance to neutron radiotherapy and impose strict criteria for normalizing and testing nuclear models used to calculate kerma factors at higher neutron energies

  12. Neutrons and art

    International Nuclear Information System (INIS)

    Panczyk, E.; Walis, L.

    2004-01-01

    Following modern trends in art objects connoisseurship, through examination of the structure of art objects supports traditional studies conducted by art historians based on composition, iconographic and stylistic comparisons. It must be emphasized that complete technological examinations are carried out by means of comprehensive physical and chemical studies. Among various methods used for the examination of art objects, methods which apply neutrons such as instrumental neutron activation analysis (INAA), prompt gamma activation analysis (PGAA) and neutron-induced autoradiography are crucial due to their high sensitivity, reproducibility and capability of simultaneous determination of several tens of elements. Systematic studies on art objects using instrumental neutron activation analysis and neutron autoradiography have been carried out in the institute of Nuclear Chemistry and Technology. It was possible to accumulate a number of essential data on the concentration of trace elements particularly in chalk grounds and pigments (such as lead white, lead-tin yellow, smalt), Chinese porcelain, Thai ceramics, silver denarius, jewellery made of copper alloys, as well as in the clay fillings of Egyptian mummies. The above mentioned examination of art objects prior to their conservation helps to determine precisely the materials used in the process of creating art objects, as well as to identify the appropriate place of origin of particular materials. (author)

  13. A comparison of some of the characteristics of patients with occupational and non-occupational asthma.

    Science.gov (United States)

    Axon, E J; Beach, J R; Burge, P S

    1995-04-01

    Occupational asthma is the most frequently diagnosed occupational lung disease reported to the SWORD (Surveillance of Work-related and Occupational Respiratory Disease) scheme. However, diagnosing occupational asthma is not straightforward, and establishing a link with work may be difficult. This study was undertaken to determine the differences between patients with occupational asthma and those with non-occupational asthma which might help in their diagnosis. Information was collected using a self-completed questionnaire. Questionnaires were distributed to 30 subjects aged 18-65 years at each of two clinics--one for patients with occupational asthma and one for those with cryptogenic and environmental asthma. Replies were received from 26 patients with occupational asthma (87%) and 29 patients with non-occupational asthma (97%). The age of onset was significantly higher for those with occupational asthma (42.6 vs 20.7 years). Significantly more subjects with occupational asthma reported improvement on holiday, whereas no significant difference was found in the numbers reporting worsening of symptoms on work days. Those with occupational asthma were less likely to report seasonal variation in symptoms, exacerbation by allergies, pets and stress, or a family history of asthma. Subjects with occupational asthma were more likely to become unemployed (50% vs 3%). Recognition of some of these features in a patient's history may help in the difficult task of differentiating occupational from non-occupational asthma, potentially avoiding the need for exhaustive investigations in some patients. The high prevalence of holiday improvement among subjects with non-occupational asthma suggested that domestic or environmental allergies arising outside the workplace may have been making an important contribution to ongoing symptoms in these subjects.

  14. UCN gravity spectrometry using neutron interference filters for fundamental investigations in neutron optics

    CERN Document Server

    Bondarenko, I V; Cimmino, A; Geltenbort, P; Frank, A I; Hoghoj, P; Klein, A G; Masalovich, S V; Nosov, V G

    2000-01-01

    A Gravity Spectrometer for ultra-cold neutrons (UCN) using neutron interference filters has been designed and tested. An energy resolution of the order of 6.5 neV was obtained which is good enough for performing a number of neutron-optical experiments proposed in an earlier paper. Experimental tests of the UCN dispersion law are currently in progress.

  15. UCN gravity spectrometry using neutron interference filters for fundamental investigations in neutron optics

    International Nuclear Information System (INIS)

    Bondarenko, I.V.; Balashov, S.N.; Cimmino, A.; Geltenbort, P.; Frank, A.I.; Hoghoj, P.; Klein, A.G.; Masalovich, S.V.; Nosov, V.G.

    2000-01-01

    A Gravity Spectrometer for ultra-cold neutrons (UCN) using neutron interference filters has been designed and tested. An energy resolution of the order of 6.5 neV was obtained which is good enough for performing a number of neutron-optical experiments proposed in an earlier paper. Experimental tests of the UCN dispersion law are currently in progress

  16. Neutron diffraction and lattice defects

    International Nuclear Information System (INIS)

    Hamaguchi, Yoshikazu

    1974-01-01

    Study on lattice defects by neutron diffraction technique is described. Wave length of neutron wave is longer than that of X-ray, and absorption cross-section is small. Number of defects observed by ESR is up to several defects, and the number studied with electron microscopes is more than 100. Information obtained by neutron diffraction concerns the number of defects between these two ranges. For practical analysis, several probable models are selected from the data of ESR or electron microscopes, and most probable one is determined by calculation. Then, defect concentration is obtained from scattering cross section. It is possible to measure elastic scattering exclusively by neutron diffraction. Minimum detectable concentration estimated is about 0.5% and 10 20 - 10 21 defects per unit volume. A chopper and a time of flight system are used as a measuring system. Cold neutrons are obtained from the neutron sources inserted into reactors. Examples of measurements by using similar equipments to PTNS-I system of Japan Atomic Energy Research Institute are presented. Interstitial concentration in the graphite irradiated by fast neutrons is shown. Defects in irradiated MgO were also investigated by measuring scattering cross section. Study of defects in Ge was made by measuring total cross section, and model analysis was performed in comparison with various models. (Kato, T.)

  17. Neutron detector

    International Nuclear Information System (INIS)

    Endo, Hiroshi.

    1993-01-01

    The device of the present invention detects neutrons in a reactor container under a high temperature and reduces the noise level in an FBR type reactor. That is, the detection section comprises a high heat resistant vessel containing a scintillator therein for detecting neutrons. Neutron signals sent from the detection section are inputted to a neutron measuring section by way of a signal transmission section. The detection section is disposed at the inside of the reactor container. Further, the signal transmission section is connected optically to the detection section. With such a constitution, since the detection section comprising the high temperature resistant vessel is disposed at the inside of the reactor container, neutron fluxes can be detected and measured at high sensitivity even under a high temperature circumstance. Since the signal transmission section is optically connected to the detection section, influence of radiation rays upon transmission of the neutron detection signals can be reduced. Accordingly, the noise level can be kept low. (I.S.)

  18. Neutron Scattering

    International Nuclear Information System (INIS)

    Fayer, Michael J.; Gee, Glendon W.

    2005-01-01

    The neutron probe is a standard tool for measuring soil water content. This article provides an overview of the underlying theory, describes the methodology for its calibration and use, discusses example applications, and identifies the safety issues. Soil water makes land-based life possible by satisfying plant water requirements, serving as a medium for nutrient movement to plant roots and nutrient cycling, and controlling the fate and transport of contaminants in the soil environment. Therefore, a successful understanding of the dynamics of plant growth, nutrient cycling, and contaminant behavior in the soil requires knowledge of the soil water content as well as its spatial and temporal variability. After more than 50 years, neutron probes remain the most reliable tool available for field monitoring of soil water content. Neutron probes provide integrated measurements over relatively large volumes of soil and, with proper access, allow for repeated sampling of the subsurface at the same locations. The limitations of neutron probes include costly and time-consuming manual operation, lack of data automation, and costly regulatory requirements. As more non-radioactive systems for soil water monitoring are developed to provide automated profiling capabilities, neutron-probe usage will likely decrease. Until then, neutron probes will continue to be a standard for reliable measurements of field water contents in soils around the globe

  19. A Neutron Radiography System for Field Use

    Science.gov (United States)

    1989-06-01

    provoked a major renewal of interest in neutron radiography because it promises to bring neutron radiography to the workplace , a convenience provided...II I~F I C II i IiH i ii MTL TR 89-52 I-AD A NEUTRON RADIOGRAPHY SYSTEM N FOR FIELD USE e~m JOHN J. ANTAL and ALFRED S. MAROTTA, and LOUIS J. FARESE...COVERED A NEUTRON RADIOGRAPHY SYSTEM FOR FIELD USE Final Report 6. PERFORMING OR1. REPORT NUMBER 7. AUTHOR(s) S. CONTRACT OR GRANT NUMBER(s) John J

  20. Cold neutron production and application

    International Nuclear Information System (INIS)

    Inoue, Kazuhiko; Watanabe, Noboru.

    1976-01-01

    The first part gives general introduction to cold neutrons, namely the definition and the role as a probe in basic science and technology. The second part reviews various methods of cold neutron production. Some physical characteristics required for cold moderators are presented, and a list summarizes a number of cold moderators and their reactor physics constants. The definition of flux gain factor and the measured values for liquid light- and heavy-hydrogen are also given. The cold neutron spectra in methane and liquid hydrogen measured by LINAC time-of-flight method are presented to show the advantage of solid methane. The cold neutron sources using experimental reactors or linear accelerators are explained along with the examples of existing facilities. Two Japanese programs, the one is the use of a high flux reactor and the other is the use of a LINAC, are also presented. The third part of this report reviews the application areas of cold neutrons. (Aoki, K.)

  1. Single Crystal Diffuse Neutron Scattering

    Directory of Open Access Journals (Sweden)

    Richard Welberry

    2018-01-01

    Full Text Available Diffuse neutron scattering has become a valuable tool for investigating local structure in materials ranging from organic molecular crystals containing only light atoms to piezo-ceramics that frequently contain heavy elements. Although neutron sources will never be able to compete with X-rays in terms of the available flux the special properties of neutrons, viz. the ability to explore inelastic scattering events, the fact that scattering lengths do not vary systematically with atomic number and their ability to scatter from magnetic moments, provides strong motivation for developing neutron diffuse scattering methods. In this paper, we compare three different instruments that have been used by us to collect neutron diffuse scattering data. Two of these are on a spallation source and one on a reactor source.

  2. Synovectomy by Neutron capture; Sinovectomia por captura de neutrones

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H.R.; Torres M, C. [Centro Regional de Estudios Nucleares, Universidad Autonoma de Zacatecas, C. Cipres 10, Fracc. La Penuela, 98000 Zacatecas (Mexico)

    1998-12-31

    The Synovectomy by Neutron capture has as purpose the treatment of the rheumatoid arthritis, illness which at present does not have a definitive curing. This therapy requires a neutron source for irradiating the articulation affected. The energy spectra and the intensity of these neutrons are fundamental since these neutrons induce nuclear reactions of capture with Boron-10 inside the articulation and the freely energy of these reactions is transferred at the productive tissue of synovial liquid, annihilating it. In this work it is presented the neutron spectra results obtained with moderator packings of spherical geometry which contains in its center a Pu{sup 239} Be source. The calculations were realized through Monte Carlo method. The moderators assayed were light water, heavy water base and the both combination of them. The spectra obtained, the average energy, the neutron total number by neutron emitted by source, the thermal neutron percentage and the dose equivalent allow us to suggest that the moderator packing more adequate is what has a light water thickness 0.5 cm (radius 2 cm) and 24.5 cm heavy water (radius 26.5 cm). (Author)

  3. Neutronics of the IFMIF neutron source: development and analysis

    International Nuclear Information System (INIS)

    Wilson, P.P.H.

    1999-01-01

    The accurate analysis of this system required the development of a code system and methodology capable of modelling the various physical processes. A generic code system for the neutronics analysis of neutron sources has been created by loosely integrating existing components with new developments: the data processing code NJOY, the Monte Carlo neutron transport code MCNP, and the activation code ALARA were supplemented by a damage data processing program, damChar, and integrated with a number of flexible and extensible modules for the Perl scripting language. Specific advances were required to apply this code system to IFMIF. Based on the ENDF-6 data format requirements of this system, new data evaluations have been implemented for neutron transport and activation. Extensive analysis of the Li(d, xn) reaction has led to a new MCNP source function module, M c DeLi, based on physical reaction models and capable of accurate and flexible modelling of the IFMIF neutron source term. In depth analyses of the neutron flux spectra and spatial distribution throughout the high flux test region permitted a basic validation of the tools and data. The understanding of the features of the neutron flux provided a foundation for the analyses of the other neutron responses. (orig./DGE) [de

  4. Pulsed neutron generator for logging

    International Nuclear Information System (INIS)

    Thibideau, F.D.

    1977-01-01

    A pulsed neutron generator for uranium logging is described. This generator is one component of a prototype uranium logging probe which is being developed by SLA to detect, and assay, uranium by borehole logging. The logging method is based on the measurement of epithermal neutrons resulting from the prompt fissioning of uranium from a pulsed source of 17.6 MeV neutrons. An objective of the prototype probe was that its diameter not exceed 2.75 inches, which would allow its use in conventional rotary drill holes of 4.75-inch diameter. This restriction limited the generator to a maximum 2.375-inch diameter. The performance requirements for the neutron generator specified that it operate with a nominal output of 5 x 10 6 neutrons/pulse at up to 100 pulses/second for a one-hour period. The development of a neutron generator meeting the preliminary design goals was completed and two prototype models were delivered to SLA. These two generators have been used by SLA to log a number of boreholes in field evaluation of the probe. The results of the field evaluations have led to the recommendation of several changes to improve the probe's operation. Some of these changes will require additional development effort on the neutron generator. It is expected that this work will be performed during 1977. The design and operation of the first prototype neutron generators is described

  5. CARNAC, Neutron Flux and Neutron Spectra in Criticality Accident

    International Nuclear Information System (INIS)

    Bessis, J.

    1976-01-01

    Nature of physical problem solved: Calculation of flux and neutron spectra in the case of a criticality accident. The method is unsophisticated but fast. The program is divided into two parts: (1) The code CRITIC is based on the Fermi age equation and evaluates the neutron number per fission emitted from a moderate critical system and its energy spectrum. (2) The code NARCISSE uses concrete current albedo, evaluates the product of neutron reflection on walls of the source containment and calculates the resulting flux at any point, and its energy distribution into 21 groups. The results obtained seem satisfactory, if compared with a Monte Carlo program

  6. Development of Cold Neutron Activation Station at HANARO Cold Neutron Source

    International Nuclear Information System (INIS)

    Sun, G. M.; Hoang, S. M. T.; Moon, J. H.; Chung, Y. S.; Cho, S. J.; Lee, K. H.; Park, B. G.; Choi, H. D.

    2012-01-01

    A new cold neutron source at the HANARO Research Reactor had been constructed in the framework of a five-year project, and ended in 2009. It has seven neutron guides, among which five guides were already allocated for a number of neutron scattering instruments. A new two-year project to develop a Cold Neutron Activation Station (CONAS) was carried out at the two neutron guides since May 2010, which was supported by the program of the Ministry of Education, Science and Technology, Korea. Fig. 1 shows the location of CONAS. CONAS is a complex facility including several radioanalytical instruments utilizing neutron capture reaction to analyze elements in a sample. It was designed to include three instruments like a CN-PGAA (Cold Neutron - Prompt Gamma Activation Analysis), a CN-NIPS (Cold Neutron - Neutron Induced Pair Spectrometer), and a CN-NDP (Cold Neutron - Neutron-induced prompt charged particle Depth Profiling). Fig. 2 shows the conceptual configuration of the CONAS concrete bioshield and the instruments. CN-PGAA and CN-NIPS measure the gamma-rays promptly emitted from the sample after neutron capture, whereas CN-NDP is a probe to measure the charged particles emitted from the sample surface after neutron capture. For this, we constructed two cold neutron guides called CG1 and CG2B guides from the CNS

  7. Studying historical occupational careers with multilevel growth models

    NARCIS (Netherlands)

    Schulz, W.; Maas, I.

    2010-01-01

    In this article we propose to study occupational careers with historical data by using multilevel growth models. Historical career data are often characterized by a lack of information on the timing of occupational changes and by different numbers of observations of occupations per individual.

  8. Neutron radiography for nondestructive testing

    International Nuclear Information System (INIS)

    John, J.

    1979-01-01

    Neutron radiography is similar to X-ray inspection in that both depend upon use of radiation that penetrates some materials and is absorbed by others to provide a contrast image of conditions not readily available for visual inspection. X-rays are absorbed by dense materials, such as metals, whereas neutrons readily penetrate metals, but are absorbed by materials containing hydrogen. The neutron radiography has been successfully applied to a number of inspection situations. These include the inspection of explosives, advanced composites, adhesively bonded structures and a number of aircraft engine components. With the availability of Californium-252, it has become feasible to construct mobile neutron radiography systems suitable for field use. Such systems have been used for in-situ inspection of flight line aircraft, particularly to locate and measure hidden corrosion

  9. neutron radiography

    International Nuclear Information System (INIS)

    Barton, J.P.

    1993-01-01

    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)

  10. Pulsed neutron sources at KAON

    International Nuclear Information System (INIS)

    Thorson, I.M.; Egelstaff, P.A.; Craddock, M.K.

    1991-01-01

    The proposed KAON Factory facility at TRIUMF consists of a number of synchrotrons and storage rings which offer proton beams of energies between 0.45 and 30 GeV with varying pulse amplitudes, widths and repetition rates. Various possibilities for feeding these beams to a pulsed neutron facility and their potential for future development are examined. The incremental cost of such a pulsed neutron facility is estimated approximately. (author)

  11. Occupational skin cancer and precancer

    Directory of Open Access Journals (Sweden)

    Fifinela Raissa

    2016-12-01

    Full Text Available Occupational skin cancer and precancerous lesions are skin disorders caused by exposure to chemical carcinogens such as polycyclic hydrocarbons and arsenic, or radiation, such as ultraviolet light and ionizing light in the workplace. Annual increase in skin cancer incidence is believed to be related to various factors such as frequent intense sunlight exposure (i.e. at work, recreational activities, and sun-tanning habit, ozone depletion, an increase in number of geriatric population, and an increase of public awareness in skin cancer. The most common occupational skin cancers are basal cell carcinoma, squamous cell carcinoma, and melanoma. Examples of occupational precancerous lesion of the skin are actinic keratosis and Bowen’s disease. Particular diagnostic criteria to diagnose occupational diseases has been developed. Early detection of occupational skin cancer and precancerous lesion is necessary. An effective prevention program consists of primary prevention such as prevention of hazardous material exposure, secondary prevention such as early detection of disease for early intervention, and tertiary prevention such as minimizing long-term impact of the disease.

  12. NEUTRONIC REACTOR

    Science.gov (United States)

    Wigner, E.P.; Weinberg, A.W.; Young, G.J.

    1958-04-15

    A nuclear reactor which uses uranium in the form of elongated tubes as fuel elements and liquid as a coolant is described. Elongated tubular uranium bodies are vertically disposed in an efficient neutron slowing agent, such as graphite, for example, to form a lattice structure which is disposed between upper and lower coolant tanks. Fluid coolant tubes extend through the uranium bodies and communicate with the upper and lower tanks and serve to convey the coolant through the uranium body. The reactor is also provided with means for circulating the cooling fluid through the coolant tanks and coolant tubes, suitable neutron and gnmma ray shields, and control means.

  13. Neutron dosimeter

    International Nuclear Information System (INIS)

    Bartko, J.; Schoch, K.F. Jr.; Congedo, T.V.; Anderson, S.L. Jr.

    1989-01-01

    This patent describes a nuclear reactor. It comprises a reactor core; a thermal shield surrounding the reactor core; a pressure vessel surrounding the thermal shield; a neutron dosimeter positioned outside of the thermal shield, the neutron dosimeter comprising a layer of fissile material and a second layer made of a material having an electrical conductivity which permanently varies as a function of its cumulative ion radiation dose; and means, outside the pressure vessel and electrically connected to the layer of second material, for measuring electrical conductivity of the layer of second material

  14. Quantitative neutron radiography using neutron absorbing honeycomb

    International Nuclear Information System (INIS)

    Tamaki, Masayoshi; Oda, Masahiro; Takahashi, Kenji; Ohkubo, Kohei; Tasaka, Kanji; Tsuruno, Akira; Matsubayashi, Masahito.

    1993-01-01

    This investigation concerns quantitative neutron radiography and computed tomography by using a neutron absorbing honeycomb collimator. By setting the neutron absorbing honeycomb collimator between object and imaging system, neutrons scattered in the object were absorbed by the honeycomb material and eliminated before coming to the imaging system, but the neutrons which were transmitted the object without interaction could reach the imaging system. The image by purely transmitted neutrons gives the quantitative information. Two honeycombs were prepared with coating of boron nitride and gadolinium oxide and evaluated for the quantitative application. The relation between the neutron total cross section and the attenuation coefficient confirmed that they were in a fairly good agreement. Application to quantitative computed tomography was also successfully conducted. The new neutron radiography method using the neutron-absorbing honeycomb collimator for the elimination of the scattered neutrons improved remarkably the quantitativeness of the neutron radiography and computed tomography. (author)

  15. Neutronics of pulsed spallation neutron sources

    CERN Document Server

    Watanabe, N

    2003-01-01

    Various topics and issues on the neutronics of pulsed spallation neutron sources, mainly for neutron scattering experiments, are reviewed to give a wide circle of readers a better understanding of these sources in order to achieve a high neutronic performance. Starting from what neutrons are needed, what the spallation reaction is and how to produce slow-neutrons more efficiently, the outline of the target and moderator neutronics are explained. Various efforts with some new concepts or ideas have already been devoted to obtaining the highest possible slow-neutron intensity with desired pulse characteristics. This paper also reviews the recent progress of such efforts, mainly focused on moderator neutronics, since moderators are the final devices of a neutron source, which determine the source performance. Various governing parameters for neutron-pulse characteristics such as material issues, geometrical parameters (shape and dimensions), the target-moderator coupling scheme, the ortho-para-hydrogen ratio, po...

  16. The Diversity of Neutron Stars

    Science.gov (United States)

    Kaplan, David L.

    2004-12-01

    Neutron stars are invaluable tools for exploring stellar death, the physics of ultra-dense matter, and the effects of extremely strong magnetic fields. The observed population of neutron stars is dominated by the >1000 radio pulsars, but there are distinct sub-populations that, while fewer in number, can have significant impact on our understanding of the issues mentioned above. These populations are the nearby, isolated neutron stars discovered by ROSAT, and the central compact objects in supernova remnants. The studies of both of these populations have been greatly accelerated in recent years through observations with the Chandra X-ray Observatory and the XMM-Newton telescope. First, we discuss radio, optical, and X-ray observations of the nearby neutron stars aimed at determining their relation to the Galactic neutron star population and at unraveling their complex physical processes by determining the basic astronomical parameters that define the population---distances, ages, and magnetic fields---the uncertainties in which limit any attempt to derive basic physical parameters for these objects. We conclude that these sources are 1e6 year-old cooling neutron stars with magnetic fields above 1e13 Gauss. Second, we describe the hollow supernova remnant problem: why many of the supernova remnants in the Galaxy have no indication of central neutron stars. We have undertaken an X-ray census of neutron stars in a volume-limited sample of Galactic supernova remnants, and from it conclude that either many supernovae do not produce neutron stars contrary to expectation, or that neutron stars can have a wide range in cooling behavior that makes many sources disappear from the X-ray sky.

  17. [Drugs and occupational accident].

    Science.gov (United States)

    Bratzke, H; Albers, C

    1996-02-01

    In a case of a fatal occupational accident (construction worker, fall from roof, urine test positive for cocaine and THC, e.g. cannabis) the question arised to what extent those drug-related occupational accidents occur. In the literature only few cases, mainly dealing with cannabis influence, have been reported, however, a higher number is suspected. Cocaine and other stimulating drugs (amphetamine) are more often used to increase physical fitness. By direct or indirect interference with vigilance these compounds may provoke accidents. Due to the lack of a legal basis proving of the influence of drugs at the working place is still very limited, although highly sensitive chemical-toxicological assay procedures are available to detect even the chronic abuse (in hair). In the general conditions of accident insurances a compensation is excluded when alcohol is involved, but drugs are not mentioned. It is indeed difficult to establish a concentration limit for drugs like that existing for alcohol (1.1%). In each case the assay of the drug involved and exact knowledge of its specific effects is in an essential prerequisite to prove the causal relationship.

  18. Occupational hearing loss

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/001048.htm Occupational hearing loss To use the sharing features on this page, please enable JavaScript. Occupational hearing loss is damage to the inner ear from noise ...

  19. Neutronic reactor

    International Nuclear Information System (INIS)

    Wende, C.W.J.

    1976-01-01

    The method of operating a water-cooled neutronic reactor having a graphite moderator is described which comprises flowing a gaseous mixture of carbon dioxide and helium, in which the helium comprises 40--60 volume percent of the mixture, in contact with the graphite moderator. 2 claims, 4 figures

  20. Neutron reflectivity

    Directory of Open Access Journals (Sweden)

    Cousin Fabrice

    2015-01-01

    Full Text Available The specular neutron reflectivity is a technique enabling the measurement of neutron scattering length density profile perpendicular to the plane of a surface or an interface, and thereby the profile of chemical composition. The characteristic sizes that are probed range from around 5 Å up 5000 Å. It is a scattering technique that averages information on the entire surface and it is therefore not possible to obtain information within the plane of the interface. The specific properties of neutrons (possibility of tuning the contrast by isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons makes it particularly interesting in the fields of soft matter, biophysics and magnetic thin films. This course is a basic introduction to the technique and does not address the magnetic reflectivity. It is composed of three parts describing respectively its principle and its formalism, the experimental aspects of the method (spectrometers, samples and two examples related to the materials for energy.

  1. Occupational radiation exposure in Slovakia

    International Nuclear Information System (INIS)

    Boehm, K.; Cabanekova, H.

    2014-01-01

    Recently are 2 nuclear power plants in operation in the Slovak republic. Apart from nuclear facilities there are 450 licensed undertakings with monitored workers. The majority of the licensed undertakings are active in health care. In Slovak republic are five dosimetry services performing assessments on personal doses due to external exposure and two dosimetry services are approved to carry out monitoring of internal exposure. Dosemeters used for the monitoring of external individual exposure include: personal whole-body film dosemeters, thermoluminescence dosemeters (TLD) or optically stimulated luminescence dosimeters (OSL) for measurements of beta and gamma radiation; TLD for measurements of neutron radiation and TLD for extremities. The measured operational dose quantities are Hp(10), Hp(3) and Hp(0.07). Approved dosimetry service reports the measured dose data to the employers and to the Central register of occupational doses (CROD). Annually are monitored about 12500 - 16200 active workers. Average effective doses per one monitored worker are presented. (author)

  2. 78 FR 64504 - Safety and Occupational Health Study Section (SOHSS), National Institute for Occupational Safety...

    Science.gov (United States)

    2013-10-29

    ... DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention Safety and Occupational Health Study Section (SOHSS), National Institute for Occupational Safety and Health (NIOSH or..., Number 177, Pages 56235-56236. Contact Person for More Information: Price Connor, Ph.D., NIOSH Health...

  3. Methods for absorbing neutrons

    Science.gov (United States)

    Guillen, Donna P [Idaho Falls, ID; Longhurst, Glen R [Idaho Falls, ID; Porter, Douglas L [Idaho Falls, ID; Parry, James R [Idaho Falls, ID

    2012-07-24

    A conduction cooled neutron absorber may include a metal matrix composite that comprises a metal having a thermal neutron cross-section of at least about 50 barns and a metal having a thermal conductivity of at least about 1 W/cmK. Apparatus for providing a neutron flux having a high fast-to-thermal neutron ratio may include a source of neutrons that produces fast neutrons and thermal neutrons. A neutron absorber positioned adjacent the neutron source absorbs at least some of the thermal neutrons so that a region adjacent the neutron absorber has a fast-to-thermal neutron ratio of at least about 15. A coolant in thermal contact with the neutron absorber removes heat from the neutron absorber.

  4. Neutron stars as cosmic neutron matter laboratories

    International Nuclear Information System (INIS)

    Pines, D.

    1986-01-01

    Recent developments which have radically changed our understanding of the dynamics of neutron star superfluids and the free precession of neutron stars are summarized, and the extent to which neutron stars are cosmic neutron matter laboratories is discussed. 17 refs., 1 tab

  5. Neutron scattering science in Australia

    Energy Technology Data Exchange (ETDEWEB)

    Knott, Robert [Australian Nuclear Science and Technology Organisation, Menai, NSW (Australia)

    1999-10-01

    Neutron scattering science in Australia is making an impact on a number of fields in the scientific and industrial research communities. The unique properties of the neutron are being used to investigate problems in chemistry, materials science, physics, engineering and biology. The reactor HIFAR at the Australian Nuclear Science and Technology Organisation research laboratories is the only neutron source in Australia suitable for neutron scattering science. A suite of instruments provides a wide range of opportunities for the neutron scattering community that extends throughout universities, government and industrial research laboratories. Plans are in progress to replace the present research reactor with a modern multi-purpose research reactor to offer the most advanced neutron scattering facilities. The experimental and analysis equipment associated with a modern research reactor will permit the establishment of a national centre for world class neutron science research focussed on the structure and functioning of materials, industrial irradiations and analyses in support of Australian manufacturing, minerals, petrochemical, pharmaceuticals and information science industries. (author)

  6. Neutron scattering science in Australia

    International Nuclear Information System (INIS)

    Knott, Robert

    1999-01-01

    Neutron scattering science in Australia is making an impact on a number of fields in the scientific and industrial research communities. The unique properties of the neutron are being used to investigate problems in chemistry, materials science, physics, engineering and biology. The reactor HIFAR at the Australian Nuclear Science and Technology Organisation research laboratories is the only neutron source in Australia suitable for neutron scattering science. A suite of instruments provides a wide range of opportunities for the neutron scattering community that extends throughout universities, government and industrial research laboratories. Plans are in progress to replace the present research reactor with a modern multi-purpose research reactor to offer the most advanced neutron scattering facilities. The experimental and analysis equipment associated with a modern research reactor will permit the establishment of a national centre for world class neutron science research focussed on the structure and functioning of materials, industrial irradiations and analyses in support of Australian manufacturing, minerals, petrochemical, pharmaceuticals and information science industries. (author)

  7. A bibliometric analysis of occupational therapy publications.

    Science.gov (United States)

    Brown, Ted; Gutman, Sharon A; Ho, Yuh-Shan; Fong, Kenneth N K

    2018-01-01

    Bibliometrics involves the statistical analysis of the publications in a specific discipline or subject area. A bibliometric analysis of the occupational therapy refereed literature is needed. A bibliometric analysis was completed of the occupational therapy literature from 1991-2014, indexed in the Science Citation Index-Expanded or the Social Sciences Citation Index. Publications were searched by title, abstract, keywords, and KeyWords Plus. Total number of article citations, citations per journal, and contributions per country, individual authors, and institution were calculated. 5,315 occupational therapy articles were published in 821 journals. It appears that there is a citation window of an approximate 10-year period between the time of publication and the peak number of citations an article receives. The top three most highly cited articles were published in Developmental Medicine and Child Neurology, JAMA, and Lancet. AJOT, BJOT and AOTJ published the largest number of occupational therapy articles with the United States, Australia, and Canada producing the highest number of publications. McMaster University, the University of Queensland, and the University of Toronto were the institutions that published the largest number of occupational therapy journal articles. The occupational therapy literature is growing and the frequency of article citation is increasing.

  8. On the mechanism of fission neutron emission

    International Nuclear Information System (INIS)

    Maerten, H.; Richter, D.; Seeliger, D.

    1986-01-01

    This review represents the present knowledge of the mechanism of prompt fission neutron emission. Starting with a brief fission process characterization related with neutron emission, possible emission mechanisms are discussed. It is emphasized that the experimental study of special mechanisms, i.e. scission neutron emission processes, requires a sufficiently correct description of emission probabilities on the base of the main mechanism, i.e. the evaporation from fully accelerated fragments. Adequate statistical-model approaches have to account for the complexity of nuclear fission reflected by an intricate fragment distribution. The present picture of scission neutron emission is not clarified neither experimentally nor theoretically. Deduced data are contradictory and depend on the used analysis procedures often involving rough discriptions of evaporated-neutron distributions. The contribution of two secondary mechanisms of fission neutron emission, i.e. the neutron evaporation during fragment acceleration and neutron emission due to the decay of 5 He after ternary fission, is estimated. We summarize the recent progress of the theoretical description of fission neutron spectra in the framework of statistical models considering the standard spectrum of 252 Cf(sf) neutrons especially. The main experimental basis for the study of fission neutron emission is the accurate measurement of emission probabilities as a function of emission energy and angle (at least) as well as fragment parameters (mass number ratio and kinetic energy). The present status is evaluated. (author)

  9. Basic of Neutron NDA

    Energy Technology Data Exchange (ETDEWEB)

    Trahan, Alexis Chanel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-09-15

    The objectives of this presentation are to introduce the basic physics of neutron production, interactions and detection; identify the processes that generate neutrons; explain the most common neutron mechanism, spontaneous and induced fission and (a,n) reactions; describe the properties of neutron from different sources; recognize advantages of neutron measurements techniques; recognize common neutrons interactions; explain neutron cross section measurements; describe the fundamental of 3He detector function and designs; and differentiate between passive and active assay techniques.

  10. Monitoring of occupational exposure in manufacturing of stainless steel constructions

    Czech Academy of Sciences Publication Activity Database

    Kučera, Jan; Bencko, V.; Pápayová, A.; Šaligová, D.; Tejral, J.; Borská, L.

    2001-01-01

    Roč. 9, - (2001), s. 171-175 ISSN 1210-7778 R&D Projects: GA ČR GV202/97/K038 Institutional research plan: CEZ:AV0Z1048901 Keywords : occupational exposure * stainless steel construction industry * instrumental neutron activation analysis Subject RIV: FP - Other Medical Disciplines

  11. Properties of the TRIUMF neutron beam

    International Nuclear Information System (INIS)

    Gan, L.; Berdoz, A.R.; Green, P.W.; Greeniaus, L.G.; Helmer, R.; Korkmaz, E.; Lee, L.; Miller, C.A.; Opper, A.K.; Page, S.A.; Van Oers, W.T.H.; Zhao, J.

    1995-01-01

    Properties of the TRIUMF neutron beam (4A/2) are presented and compared with a Monte Carlo prediction. The beam intensity profile, energy spectrum and polarization are predicted taking into account the beamline geometry, energy losses in the LD 2 production target, the properties of the vector pd→ vector npp reaction, and the scattering of neutrons from the collimator walls. The results allow for improved corrections to systematic errors in a number of TRIUMF neutron experiments. (orig.)

  12. Extension of the AUS reactor neutronics system for application to fusion blanket neutronics

    International Nuclear Information System (INIS)

    Robinson, G.S.

    1984-03-01

    The AUS modular code scheme for reactor neutronics computations has been extended to apply to fusion blanket neutronics. A new group cross-section library with 200 neutron groups, 37 photon groups and kerma factor data has been generated from ENDF/B-IV. The library includes neutron resonance subgroup parameters and temperature-dependent data for thermal neutron scattering matrices. The validity of the overall calculation system for fusion applications has been checked by comparison with a number of published conceptual design studies

  13. [Current status of occupational health and related countermeasures in Guangzhou, China].

    Science.gov (United States)

    Zeng, W F; Wu, S H; Wang, Z; Liu, Y M

    2016-02-20

    To investigate the current status of occupational health and related countermeasures in Guangzhou, China. Related data were collected from occupational poisoning accident investigation, diagnosis and identification of occupational diseases, and the occupational disease hazard reporting system, and the statistical data of occupational health in Guangzhou were analyzed retrospectively. The number of enterprises reporting for occupational disease hazards in Guangzhou was 20 890, and the total number of workers was 1 457 583. The number of workers exposed to occupational hazards was 284 233, and the cumulative number of workers with occupational diseases was 1 502. There were many risk factors for occupational diseases in enterprises, and there were a large number of workers with occupational diseases, as well as newly diagnosed cases. From 2001 to 2014, the total number of cases of occupational diseases was 958. The situation for the prevention and control of occupational diseases is grim in Guangzhou. Occupational health supervision and law enforcement should be enhanced, the three-level supervision system should be established and perfected, and the occupational health supervision system with a combination of "prevention, treatment, and protection" should be established and promoted, so as to gradually establish a technical service support system for occupational health.

  14. Neutron personnel dosimetry considerations for fusion reactors

    International Nuclear Information System (INIS)

    Barton, T.P.; Easterly, C.E.

    1979-07-01

    The increasing development of fusion reactor technology warrants an evaluation of personnel neutron dosimetry systems to aid in the concurrent development of a radiation protection program. For this reason, current state of knowledge neutron dosimeters have been reviewed with emphasis placed on practical utilization and the problems inherent in each type of dosimetry system. Evaluations of salient parameters such as energy response, latent image instability, and minimum detectable dose equivalent are presented for nuclear emulsion films, track etch techniques, albedo and other thermoluminescent dosimetry techniques, electrical conductivity damage effects, lyoluminescence, thermocurrent, and thermally stimulated exoelectron emission. Brief summaries of dosimetry regulatory requirements and intercomparison study results help to establish compliance and recent trends, respectively. Spectrum modeling data generated by the Neutron Physics Division of Oak Ridge National Laboratory for the Princeton Tokamak Fusion Test Reactor (TFTR) Facility have been analyzed by both International Commission on Radiological Protection fluence to dose conversion factors and an adjoint technique of radiation dosimetry, in an attempt to determine the applicability of current neutron dosimetry systems to deuterium and tritium fusion reactor leakage spectra. Based on the modeling data, a wide range of neutron energies will probably be present in the leakage spectra of the TFTR facility, and no appreciable risk of somatic injury to occupationally exposed workers is expected. The relative dose contributions due to high energy and thermal neutrons indicate that neutron dosimetry will probably not be a serious limitation in the development of fusion power

  15. Advances in neutron based bulk explosive detection

    Science.gov (United States)

    Gozani, Tsahi; Strellis, Dan

    2007-08-01

    Neutron based explosive inspection systems can detect a wide variety of national security threats. The inspection is founded on the detection of characteristic gamma rays emitted as the result of neutron interactions with materials. Generally these are gamma rays resulting from thermal neutron capture and inelastic scattering reactions in most materials and fast and thermal neutron fission in fissile (e.g.235U and 239Pu) and fertile (e.g.238U) materials. Cars or trucks laden with explosives, drugs, chemical agents and hazardous materials can be detected. Cargo material classification via its main elements and nuclear materials detection can also be accomplished with such neutron based platforms, when appropriate neutron sources, gamma ray spectroscopy, neutron detectors and suitable decision algorithms are employed. Neutron based techniques can be used in a variety of scenarios and operational modes. They can be used as stand alones for complete scan of objects such as vehicles, or for spot-checks to clear (or validate) alarms indicated by another inspection system such as X-ray radiography. The technologies developed over the last two decades are now being implemented with good results. Further advances have been made over the last few years that increase the sensitivity, applicability and robustness of these systems. The advances range from the synchronous inspection of two sides of vehicles, increasing throughput and sensitivity and reducing imparted dose to the inspected object and its occupants (if any), to taking advantage of the neutron kinetic behavior of cargo to remove systematic errors, reducing background effects and improving fast neutron signals.

  16. Absolute measurement of the subcriticality based on the third order neutron correlation in consideration of the finite nature of neutron counts data

    International Nuclear Information System (INIS)

    Endo, Tomohiro; Kitamura, Yasunori; Yamane, Yoshihiro

    2003-01-01

    We have studied a measurement of subcriticality by using the neutron correlation method. Furuhashi proposed an absolute measurement of subcriticality by using the third order neutron correlation factor X in addition to the second order neutron correlation factor Y. In actual experiments, the number of neutron counts data is not infinity so that we take the effect of the finite nature of the neutron counts data into account. We derived new formulas in consideration of the number of data and verified them. (author)

  17. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2013-01-01

    The following topics are dealt with: Neutron sources, symmetry of crystals, nanostructures investigated by small-angle neutron scattering, structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic neutron scattering, strongly correlated electrons, polymer dynamics, applications of neutron scattering. (HSI)

  18. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2012-01-01

    The following topics are dealt with: Neutron scattering in contemporary research, neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)

  19. Pulsed neutron generator

    International Nuclear Information System (INIS)

    Bespalov, D.F.; Bykovskii, Yu.A.; Vergun, I.I.; Kozlovskii, K.I.; Kozyrev, Yu.P.; Leonov, R.K.; Simagin, B.I.; Tsybin, A.S.; Shikanov, A.Ie.

    1986-03-01

    The paper describes a new device for generating pulsed neutron fields, utilized in nuclear geophysics for carrying out pulsed neutron logging and activation analysis under field conditions. The invention employs a sealed-off neutron tube with a laser ion source which increases neutron yield to the level of 10 neutrons per second or higher. 2 refs., 1 fig

  20. Does the Level of Occupational Aggregation Affect Estimates of the Gender Wage Gap?

    Science.gov (United States)

    Kidd, Michael P.; Shannon, Michael

    1996-01-01

    Using data from the 1989 Canadian Labour-Market Activity Survey, when occupation is treated as a productivity-related characteristic, gender wage gap estimates are distorted. Using a larger number of occupations, the occupational aggregation by gender reflects barriers women face in attempting to enter male-dominated occupations. (SK)

  1. Neutron Detector Signal Processing to Calculate the Effective Neutron Multiplication Factor of Subcritical Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Talamo, Alberto [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Gohar, Yousry [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

    2016-06-01

    This report describes different methodologies to calculate the effective neutron multiplication factor of subcritical assemblies by processing the neutron detector signals using MATLAB scripts. The subcritical assembly can be driven either by a spontaneous fission neutron source (e.g. californium) or by a neutron source generated from the interactions of accelerated particles with target materials. In the latter case, when the particle accelerator operates in a pulsed mode, the signals are typically stored into two files. One file contains the time when neutron reactions occur and the other contains the times when the neutron pulses start. In both files, the time is given by an integer representing the number of time bins since the start of the counting. These signal files are used to construct the neutron count distribution from a single neutron pulse. The built-in functions of MATLAB are used to calculate the effective neutron multiplication factor through the application of the prompt decay fitting or the area method to the neutron count distribution. If the subcritical assembly is driven by a spontaneous fission neutron source, then the effective multiplication factor can be evaluated either using the prompt neutron decay constant obtained from Rossi or Feynman distributions or the Modified Source Multiplication (MSM) method.

  2. Neutron Detector Signal Processing to Calculate the Effective Neutron Multiplication Factor of Subcritical Assemblies

    International Nuclear Information System (INIS)

    Talamo, Alberto; Gohar, Yousry

    2016-01-01

    This report describes different methodologies to calculate the effective neutron multiplication factor of subcritical assemblies by processing the neutron detector signals using MATLAB scripts. The subcritical assembly can be driven either by a spontaneous fission neutron source (e.g. californium) or by a neutron source generated from the interactions of accelerated particles with target materials. In the latter case, when the particle accelerator operates in a pulsed mode, the signals are typically stored into two files. One file contains the time when neutron reactions occur and the other contains the times when the neutron pulses start. In both files, the time is given by an integer representing the number of time bins since the start of the counting. These signal files are used to construct the neutron count distribution from a single neutron pulse. The built-in functions of MATLAB are used to calculate the effective neutron multiplication factor through the application of the prompt decay fitting or the area method to the neutron count distribution. If the subcritical assembly is driven by a spontaneous fission neutron source, then the effective multiplication factor can be evaluated either using the prompt neutron decay constant obtained from Rossi or Feynman distributions or the Modified Source Multiplication (MSM) method.

  3. Neutron radiotherapy

    International Nuclear Information System (INIS)

    Thomas, F.J.

    1987-01-01

    The rationale for the application of neutron radiation for the treatment of malignancies is well established based on radiobiological studies. These factors include the presence of tissue hypoxia, radiation response as a function of cell cycle kinetics, the repair capacity of the malignant cells and the regeneration of malignant cells during a fractionated course of radiation. Despite the constraints under which the clinical trials to date have been conducted, promising results have been obtained. Randomized trials have demonstrated that neutron therapy is the treatment of choice for inoperable salivary gland carcinomas. A randomized trial of the RTOG has demonstrated a probable advantage for neutron radiation in the treatment of advanced prostate carcinomas but is yet to be confirmed. An improvement in local control has also been observed for selected sarcomas. Equivocal or contradictory results have been obtained for squamous cell carcinomas of the head and neck, bronchogenic carcinomas, advanced rectal, transitional cell carcinomas of the bladder and cervical carcinomas. The practical consequences of these radiobiological and clinical observations on the current generation of clinical trials is discussed

  4. Investigation of the reflection of fast neutrons

    International Nuclear Information System (INIS)

    Devillers, Christian; Hasselin, Gilbert

    1964-10-01

    The authors report the study of the reflection of fast neutrons on a plane plate having a finite and varying thickness and an infinite width. Calculations are performed by using a Monte-Carlo method which allows the number, the energy, the direction, the emergence point of neutrons reflected on a plate, to be computed with respect to the energy and direction of incident neutrons. The author present how paths, elastic and inelastic shocks, direction after shock are calculated. Different information are calculated: the numbers of elastic shocks, inelastic shocks and transmitted neutrons, the number, energy and dose albedo, the spectrum and angular distribution, the distribution of neutron in terms of energy and direction

  5. Deduction of solar neutron fluences from large gamma-ray flares

    International Nuclear Information System (INIS)

    Yoshimori, Masato; Watanabe, Hiroyuki; Takahashi, Kazuyoshi.

    1986-01-01

    Solar neutron fluences from large gamma-ray flares are deduced from accelerated proton spectra and numbers derived from the gamma-ray observations. The deduced solar neutron fluences range from 1 to 200 neutrons cm -2 . The present result indicates a possibility that high sensitivity ground-based neutron monitors can detect solar neutron events, just as detected by the Jungfraujoch and Rome neutron monitors. (author)

  6. Scattering of Neutrons by an Anharmonic Crystal

    Energy Technology Data Exchange (ETDEWEB)

    Hoegberg, T; Bohlin, L; Ebbsjoe, I

    1967-04-15

    Numerical calculations have been performed for the anharmonic effects in neutron scattering. The phonon frequency widths and shifts have been calculated as a function of neutron frequency at different wave numbers and temperatures for a potential with central symmetry and for a face-centered cubic lattice.

  7. New portable neutron generator for well logging

    International Nuclear Information System (INIS)

    Chicanov, A.E.; Gromov, E. V.; Gulko, V. M.; Izmailov, A. V.

    1994-01-01

    The information about the design, investigation and testing of new well neutron generator for the pulse neutron logging (PNL) is given in this paper. The main physical characteristics of new PNL apparatus are: Neutron flux 2.10 sup 8 n/s ; Pulse frequency>=400 Hz; Diameter= 90 mm; Logging velocity >200 m/h; Number of probes = 2; Resource > 300 h. The generator were provided by gas-filled neutron accelerative tube named NTF-2. The perspective of application and optimization shown PNL apparatus are considered. (author)

  8. Administrative and research needs associated with the control of occupational exposures in commercial nuclear power plants

    International Nuclear Information System (INIS)

    Moeller, D.W.

    1980-01-01

    This review of occupational exposures in commercial nuclear power plants in the United States of America has revealed that, although many problem areas are being adequately addressed, there is a need for additional work. Areas relative to exposure evaluation that need attention include better data collection and analysis as to when and where exposures occur, improved information on exposures from internally deposited radionuclides, improved techniques for monitoring occupational neutron exposures, and an upgrading in quality control procedures in the manufacture, calibration, use and maintenance of monitoring instruments. Areas relative to exposure control that need attention include the development of additional design and manufacturing approaches for preventing the production and build-up of key radionuclides within reactor cooling systems, the development and testing of techniques for removing those radionuclides that do accumulate in such systems, the application of risk/benefit assessments to procedures for the maintenance, repair, modification, replacement and disposal of major nuclear power plant components, such as steam generators, and the development of design features to facilitate the decommissioning of nuclear power plants. Professional radiation workers also have to be aware of the impact that the proposed major reductions in occupational dose limits would have on their operations. This impact is compounded by the fact that the number of people receiving graduate education in radiation protection in the USA is decreasing. (author)

  9. Neutron scattering on equilibrium and nonequilibrium phonons, excitons and polaritons

    International Nuclear Information System (INIS)

    Broude, V.L.; Sheka, E.F.

    1978-01-01

    A number of problems of solid-state physics representing interest for neutron spectroscopy of future is considered. The development of the neutron inelastic scattering spectroscopy (neutron spectroscopy of equilibrium phonons) is discussed with application to nuclear dynamics of crystals in the thermodynamic equilibrium. The results of high-flux neutron source experiments on molecular crystals are presented. The advantages of neutron inelastic scattering over optical spectroscopy are discussed. The spectroscopy of quasi-equilibrium and non-equilibrium quasi-particles is discussed. In particular, the neutron scattering on polaritons, excitons in thermal equilibrium and production of light-excitons are considered. The problem of the possibility of such experiments is elucidated

  10. Spallation Neutron Source (SNS)

    Data.gov (United States)

    Federal Laboratory Consortium — The SNS at Oak Ridge National Laboratory is a next-generation spallation neutron source for neutron scattering that is currently the most powerful neutron source in...

  11. Neutron shielding for a 252 Cf source

    International Nuclear Information System (INIS)

    Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M.; Eduardo Gallego, Alfredo Lorente

    2006-01-01

    To determine the neutron shielding features of water-extended polyester a Monte Carlo study was carried out. Materials with low atomic number are predominantly used for neutron shielding because these materials effectively attenuate neutrons, mainly through inelastic collisions and absorption reactions. During the selection of materials to design a neutron shield, prompt gamma production as well as radionuclide production induced by neutron activation must be considered. In this investigation the Monte Carlo method was used to evaluate the performance of a water-extended polyester shield designed for the transportation, storage, and use of a 252 Cf isotopic neutron source. During calculations a detailed model for the 252 Cf and the shield was utilized. To compare the shielding features of water extended polyester, the calculations were also made for the bare 252 Cf in vacuum, air and the shield filled with water. For all cases the calculated neutron spectra was utilized to determine the ambient equivalent neutron dose at four sites around the shielding. In the case of water extended polyester and water shielding the calculations were extended to include the prompt gamma rays produced during neutron interactions, with this information the Kerma in air was calculated at the same locations where the ambient equivalent neutron dose was determined. (Author)

  12. Physics of neutron emission in fission

    International Nuclear Information System (INIS)

    Lemmel, H.D.

    1989-06-01

    The document contains the proceedings of the IAEA Consultants' Meeting on the Physics of Neutron Emission in Fission, Mito City (Japan), 24-27 May 1988. Included are the conclusions and recommendations reached at the meeting and the papers presented by the meeting participants. These papers cover the following topics: Energy dependence of the number of fission neutrons ν-bar (3 papers), multiplicity distribution of fission neutrons (3 papers), competition between neutron and γ-ray emission (4 papers), the fission neutron yield in resonances (2 papers) and the energy spectrum of fission neutrons in experiment (9 papers), theory (4 papers) and evaluation (1 paper). A separate abstract was prepared for each of these papers. Refs, figs and tabs

  13. Simulation of Neutron Backscattering applied to organic material detection

    International Nuclear Information System (INIS)

    Forero, N. C.; Cruz, A. H.; Cristancho, F.

    2007-01-01

    The Neutron Backscattering technique is tested when performing the task of localizing hydrogenated explosives hidden in soil. Detector system, landmine, soil and neutron source are simulated with Geant4 in order to obtain the number of neutrons detected when several parameters like mine composition, relative position mine-source and soil moisture are varied

  14. High energy neutron radiography

    International Nuclear Information System (INIS)

    Gavron, A.; Morley, K.; Morris, C.; Seestrom, S.; Ullmann, J.; Yates, G.; Zumbro, J.

    1996-01-01

    High-energy spallation neutron sources are now being considered in the US and elsewhere as a replacement for neutron beams produced by reactors. High-energy and high intensity neutron beams, produced by unmoderated spallation sources, open potential new vistas of neutron radiography. The authors discuss the basic advantages and disadvantages of high-energy neutron radiography, and consider some experimental results obtained at the Weapons Neutron Research (WNR) facility at Los Alamos

  15. Neutron scattering. Lectures

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2010-07-01

    The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)

  16. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2010-01-01

    The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)

  17. A measurement of the absolute neutron beam polarization produced by an optically pumped 3He neutron spin filter

    International Nuclear Information System (INIS)

    Rich, D.R.; Bowman, J.D.; Crawford, B.E.; Delheij, P.P.J.; Espy, M.A.; Haseyama, T.; Jones, G.; Keith, C.D.; Knudson, J.; Leuschner, M.B.; Masaike, A.; Masuda, Y.; Matsuda, Y.; Penttilae, S.I.; Pomeroy, V.R.; Smith, D.A.; Snow, W.M.; Szymanski, J.J.; Stephenson, S.L.; Thompson, A.K.; Yuan, V.

    2002-01-01

    The capability of performing accurate absolute measurements of neutron beam polarization opens a number of exciting opportunities in fundamental neutron physics and in neutron scattering. At the LANSCE pulsed neutron source we have measured the neutron beam polarization with an absolute accuracy of 0.3% in the neutron energy range from 40 meV to 10 eV using an optically pumped polarized 3 He spin filter and a relative transmission measurement technique. 3 He was polarized using the Rb spin-exchange method. We describe the measurement technique, present our results, and discuss some of the systematic effects associated with the method

  18. Inference for occupancy and occupancy dynamics

    Science.gov (United States)

    O'Connell, Allan F.; Bailey, Larissa L.; O'Connell, Allan F.; Nichols, James D.; Karanth, K. Ullas

    2011-01-01

    This chapter deals with the estimation of occupancy as a state variable to assess the status of, and track changes in, species distributions when sampling with camera traps. Much of the recent interest in occupancy estimation and modeling originated from the models developed by MacKenzie et al. (2002, 2003), although similar methods were developed independently (Azuma et al. 1990; Bayley and Petersen 2001; Nichols and Karanth, 2002; Tyre et al. 2003), all of which deal with species occurrence information and imperfect detection. Less than a decade after these publications, the modeling and estimation of species occurrence and occupancy dynamics have increased significantly. Special features of scientific journals have explored innovative uses of detection–nondetection data with occupancy models (Vojta 2005), and an entire volume has synthesized the use and application of occupancy estimation methods (MacKenzie et al. 2006). Reviews of the topical concepts, philosophical considerations, and various sampling designs that can be used for occupancy estimation are now readily available for a range of audiences (MacKenzie and Royle 2005; MacKenzie et al. 2006; Bailey et al. 2007; Royle and Dorazio 2008; Conroy and Carroll 2009; Kendall and White 2009; Hines et al. 2010; Link and Barker 2010). As a result, it would be pointless here to recast all that these publications have so eloquently articulated, but that said, a review of any scientific topic requires sufficient context and relevant background information, especially when relatively new methodologies and techniques such as occupancy estimation and camera traps are involved. This is especially critical in a digital age where new information is published at warp speed, making it increasingly difficult to stay abreast of theoretical advances and research developments.

  19. Human circulating ribosomal DNA content significantly increases while circulating satellite III (1q12) content decreases under chronic occupational exposure to low-dose gamma- neutron and tritium beta-radiation.

    Science.gov (United States)

    Korzeneva, Inna B; Kostuyk, Svetlana V; Ershova, Elizaveta S; Skorodumova, Elena N; Zhuravleva, Veronika F; Pankratova, Galina V; Volkova, Irina V; Stepanova, Elena V; Porokhovnik, Lev N; Veiko, Natalia N

    A single exposure to ionizing radiation (IR) results in an elevated cell-free DNA (cfDNA) content in the blood plasma. In this case, the cfDNA concentration can be a marker of the cell death in the organism. However, a chronic exposure to a low-dose IR enhances both the endonuclease activity and titer of antibodies to DNA in blood plasma, resulting in a decrease of the total concentration of circulating cfDNA in exposed people. In this case, the total cfDNA concentration should not be considered as a marker of the cell death in an exposed body. We assumed that a pool of the cfDNA circulating in the exposed people contains DNA fragments, which are resistant to a double-strand break formation in the environment of the elevated plasma endonuclease activity, and can be accumulated in the blood plasma. In order to test this hypothesis, we studied the content of GC-rich sequences (69%GC) of the transcribed region of human ribosomal repeat (rDNA), as well as the content of AT-rich repeat (63%AT) of satellite III (1q12) in the cfDNA samples obtained from 285 individuals. We have found that a chronic exposure to gamma-neutron radiation (N=88) and tritium β-radiation (N=88) evokes an increase of the rDNA content (RrDNA index) and a decrease of the satellite III content (RsatIII index) in the circulating cfDNA as compared with the cfDNA of non-exposed people (N=109). Such index that simultaneously displays both the increase of rDNA content and decrease of satellite III content in the cfDNA (RrDNA/RsatIII) can be recommended as a marker of chronic processes in the body that involve the elevated cell death rate and/or increased blood plasma endonuclease activity. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. OCCUPATIONAL EXPOSURE AND COPD

    DEFF Research Database (Denmark)

    Würtz, Else Toft

    Chronic Obstructive Pulmonary Disease (COPD) is a common disease. The main risk factor is smoking although 15% of the COPD cases are expected to be preventable if the occupational exposures from vapour, gas, dust, and fume were eliminated; the population attributable fraction (PAF). The thesis...... addresses the association between occupational exposure and COPD in a population-based cohort of Danes aged 45-84-years. 4717 participants were included at baseline and 2624 at the four year follow-up. COPD was defined by spirometry and the occupational exposure was based on specialist defined jobs...... and questionnaires. The main occupational exposure was organic dust and 49% reported no lifetime occupational exposure. The results suggest occupational exposures to be associated to COPD also in never smokers and women. We found an exposure-response relation in the cross sectional analyses. The results...

  1. High efficiency focus neutron generator

    Science.gov (United States)

    Sadeghi, H.; Amrollahi, R.; Zare, M.; Fazelpour, S.

    2017-12-01

    In the present paper, the new idea to increase the neutron yield of plasma focus devices is investigated and the results are presented. Based on many studies, more than 90% of neutrons in plasma focus devices were produced by beam target interactions and only 10% of them were due to thermonuclear reactions. While propounding the new idea, the number of collisions between deuteron ions and deuterium gas atoms were increased remarkably well. The COMSOL Multiphysics 5.2 was used to study the given idea in the known 28 plasma focus devices. In this circumstance, the neutron yield of this system was also obtained and reported. Finally, it was found that in the ENEA device with 1 Hz working frequency, 1.1 × 109 and 1.1 × 1011 neutrons per second were produced by D-D and D-T reactions, respectively. In addition, in the NX2 device with 16 Hz working frequency, 1.34 × 1010 and 1.34 × 1012 neutrons per second were produced by D-D and D-T reactions, respectively. The results show that with regards to the sizes and energy of these devices, they can be used as the efficient neutron generators.

  2. Neutron Therapy Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Neutron Therapy Facility provides a moderate intensity, broad energy spectrum neutron beam that can be used for short term irradiations for radiobiology (cells)...

  3. Calculations of neutron spectra after neutron-neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, B E [Gettysburg College, Box 405, Gettysburg, PA 17325 (United States); Stephenson, S L [Gettysburg College, Box 405, Gettysburg, PA 17325 (United States); Howell, C R [Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Mitchell, G E [North Carolina State University, Raleigh, NC 27695-8202 (United States); Tornow, W [Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Furman, W I [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Lychagin, E V [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Muzichka, A Yu [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Nekhaev, G V [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Strelkov, A V [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Sharapov, E I [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Shvetsov, V N [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)

    2004-09-01

    A direct neutron-neutron scattering length, a{sub nn}, measurement with the goal of 3% accuracy (0.5 fm) is under preparation at the aperiodic pulsed reactor YAGUAR. A direct measurement of a{sub nn} will not only help resolve conflicting results of a{sub nn} by indirect means, but also in comparison to the proton-proton scattering length, a{sub pp}, shed light on the charge-symmetry of the nuclear force. We discuss in detail the analysis of the nn-scattering data in terms of a simple analytical expression. We also discuss calibration measurements using the time-of-flight spectra of neutrons scattered on He and Ar gases and the neutron activation technique. In particular, we calculate the neutron velocity and time-of-flight spectra after scattering neutrons on neutrons and after scattering neutrons on He and Ar atoms for the proposed experimental geometry, using a realistic neutron flux spectrum-Maxwellian plus epithermal tail. The shape of the neutron spectrum after scattering is appreciably different from the initial spectrum, due to collisions between thermal-thermal and thermal-epithermal neutrons. At the same time, the integral over the Maxwellian part of the realistic scattering spectrum differs by only about 6 per cent from that of a pure Maxwellian nn-scattering spectrum.

  4. Neutron instrumentation for biology

    Energy Technology Data Exchange (ETDEWEB)

    Mason, S.A. [Institut Laue-Langevin, Grenoble (France)

    1994-12-31

    In the October 1994 round of proposals at the ILL, the external biology review sub- committee was asked to allocate neutron beam time to a wide range of experiments, on almost half the total number of scheduled neutron instruments: on 3 diffractometers, on 3 small angle scattering instruments, and on some 6 inelastic scattering spectrometers. In the 3.5 years since the temporary reactor shutdown, the ILL`s management structure has been optimized, budgets and staff have been trimmed, the ILL reactor has been re-built, and many of the instruments up-graded, many powerful (mainly Unix) workstations have been introduced, and the neighboring European Synchrotron Radiation Facility has established itself as the leading synchrotron radiation source and has started its official user program. The ILL reactor remains the world`s most intense dedicated neutron source. In this challenging context, it is of interest to review briefly the park of ILL instruments used to study the structure and energetics of small and large biological systems. A brief summary will be made of each class of experiments actually proposed in the latest ILL proposal round.

  5. Neutronic and thermalhydraulic aspects

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, J.B. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Mecanique et de Technologie; Bergeonneau, P. [CEA Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. d`Etudes des Reacteurs

    1995-12-31

    Precise computation of neutron flux in the core of a nuclear reactor represents one of the basic aspects of reactor design and operation. Neutron flux is computed by solving Boltzmann`s linear equation. Anyway, the direct solution of the equation involves too great a number of operations for practical application, leading up to TeraFlops or even PetaFlops supercomputing capabilities. Physical and mathematical models are then required to handle the extensive variety of configurations encountered. Numerical methods must be adapted to the rapid evolution of computer power, as also computer architecture: sequential, vector or parallel. Physical and mathematical models must allow for very fast estimation for online control and monitoring, adequate quantification for industrial studies and high-precision, best estimate computations. Coupling of neutronics to mechanics and two-phase flow thermohydraulics must be implemented in order to improve the accuracy in best-estimate computation schemes and to take into account the transient behaviour of the plant during normal operation or incidents. In this field of continuous improvement, the new methods applied in Reactor Physics lead obviously to good results and provide the improvements required in the future for the needs of efficiency, safety and advanced fuel cycle. This trend and the ``evolutionary`` implementation in large and modular software systems will be illustrated by the example of the SAPHYR system. (authors). 3 tabs.

  6. Neutronic and thermalhydraulic aspects

    International Nuclear Information System (INIS)

    Thomas, J.B.; Bergeonneau, P.

    1995-01-01

    Precise computation of neutron flux in the core of a nuclear reactor represents one of the basic aspects of reactor design and operation. Neutron flux is computed by solving Boltzmann's linear equation. Anyway, the direct solution of the equation involves too great a number of operations for practical application, leading up to TeraFlops or even PetaFlops supercomputing capabilities. Physical and mathematical models are then required to handle the extensive variety of configurations encountered. Numerical methods must be adapted to the rapid evolution of computer power, as also computer architecture: sequential, vector or parallel. Physical and mathematical models must allow for very fast estimation for online control and monitoring, adequate quantification for industrial studies and high-precision, best estimate computations. Coupling of neutronics to mechanics and two-phase flow thermohydraulics must be implemented in order to improve the accuracy in best-estimate computation schemes and to take into account the transient behaviour of the plant during normal operation or incidents. In this field of continuous improvement, the new methods applied in Reactor Physics lead obviously to good results and provide the improvements required in the future for the needs of efficiency, safety and advanced fuel cycle. This trend and the ''evolutionary'' implementation in large and modular software systems will be illustrated by the example of the SAPHYR system. (authors). 3 tabs

  7. Nuclear analysis methods in monitoring occupational health

    International Nuclear Information System (INIS)

    Clayton, E.

    1985-01-01

    With the increasing industrialisation of the world has come an increase in exposure to hazardous chemicals. Their effect on the body depends upon the concentration of the element in the work environment; its chemical form; the possible different routes of intake; and the individual's biological response to the chemical. Nuclear techniques of analysis such as neutron activation analysis (NAA) and proton induced X-ray emission analysis (PIXE), have played an important role in understanding the effects hazardous chemicals can have on occupationally exposed workers. In this review, examples of their application, mainly in monitoring exposure to heavy metals is discussed

  8. Evaluation of Neutron shielding efficiency of Metal hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Sang Hwan; Chae, San; Kim, Yong Soo [Hanyang University, Seoul (Korea, Republic of)

    2012-05-15

    Neutron shielding is achieved of interaction with material by moderation and absorption. Material that contains large amounts hydrogen atoms which are almost same neutron atomic weight is suited for fast neutron shielding material. Therefore, polymers containing high density hydrogen atom are being used for fast neutron shielding. On the other hand, composite materials containing high thermal neutron absorption cross section atom (Li, B, etc) are being used for thermal neutron shielding. However, these materials have low fast neutron absorption cross section. Therefore, these materials are not suited for fast neutron shielding. Hydrogen which has outstanding neutron energy reduction ability has very low thermal neutron absorption cross section, almost cannot be used for thermal neutron shielding. In this case, a large atomic number material (Pb, U, etc.) has been used. Thus, metal hydrides are considered as complement to concrete shielding material. Because metal hydrides contain high hydrogen density and elements with high atomic number. In this research neutron shielding performance and characteristic of nuclear about metal hydrides ((TiH{sub 2}, ZrH{sub 2}, HfH{sub 2}) is evaluated by experiment and MCNPX using {sup 252}Cf neutron source as purpose development shielding material to developed shielding material

  9. Human circulating ribosomal DNA content significantly increases while circulating satellite III (1q12) content decreases under chronic occupational exposure to low-dose gamma- neutron and tritium beta-radiation

    International Nuclear Information System (INIS)

    Korzeneva, Inna B.; Kostuyk, Svetlana V.; Ershova, Elizaveta S.; Skorodumova, Elena N.; Zhuravleva, Veronika F.; Pankratova, Galina V.; Volkova, Irina V.; Stepanova, Elena V.; Porokhovnik, Lev N.; Veiko, Natalia N.

    2016-01-01

    Highlights: • A transcribed region of human ribosomal repeat is resistant to double-strand breaks in the environment of a raised endonuclease activity. • Hybridization-based techniques are preferable for the analysis of damaged and/or oxidized genomic fragments, rather than the qRT-PCR method. • A chronic exposure to the low-dose IR induces an elevation of the rDNA content in the human circulating cfDNA as compared to cellular DNA. • An exposure to IR entails a decrease of the level of the human circulating satellite III (1q12) as compared to cellular DNA (RsatIII index). • The RrDNA/RsatIII ratio is a potential marker of a chronic IR individual exposure. - Abstract: A single exposure to ionizing radiation (IR) results in an elevated cell-free DNA (cfDNA) content in the blood plasma. In this case, the cfDNA concentration can be a marker of the cell death in the organism. However, a chronic exposure to a low-dose IR enhances both the endonuclease activity and titer of antibodies to DNA in blood plasma, resulting in a decrease of the total concentration of circulating cfDNA in exposed people. In this case, the total cfDNA concentration should not be considered as a marker of the cell death in an exposed body. We assumed that a pool of the cfDNA circulating in the exposed people contains DNA fragments, which are resistant to a double-strand break formation in the environment of the elevated plasma endonuclease activity, and can be accumulated in the blood plasma. In order to test this hypothesis, we studied the content of GC-rich sequences (69%GC) of the transcribed region of human ribosomal repeat (rDNA), as well as the content of AT-rich repeat (63%AT) of satellite III (1q12) in the cfDNA samples obtained from 285 individuals. We have found that a chronic exposure to gamma-neutron radiation (N = 88) and tritium β-radiation (N = 88) evokes an increase of the rDNA content (RrDNA index) and a decrease of the satellite III content (RsatIII index) in the

  10. Human circulating ribosomal DNA content significantly increases while circulating satellite III (1q12) content decreases under chronic occupational exposure to low-dose gamma- neutron and tritium beta-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Korzeneva, Inna B., E-mail: inna.korzeneva@molgen.vniief.ru [Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190 Sarov, 37 Mira ave., Nizhniy Novgorod Region (Russian Federation); Kostuyk, Svetlana V. [Research Centre for Medical Genetics, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); Ershova, Elizaveta S. [Research Centre for Medical Genetics, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); V. A. Negovsky Research Institute of General Reanimatology, Moscow, 107031 (Russian Federation); Skorodumova, Elena N.; Zhuravleva, Veronika F.; Pankratova, Galina V.; Volkova, Irina V.; Stepanova, Elena V. [Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190 Sarov, 37 Mira ave., Nizhniy Novgorod Region (Russian Federation); Porokhovnik, Lev N. [Research Centre for Medical Genetics, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); Veiko, Natalia N. [Research Centre for Medical Genetics, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); V. A. Negovsky Research Institute of General Reanimatology, Moscow, 107031 (Russian Federation)

    2016-09-15

    Highlights: • A transcribed region of human ribosomal repeat is resistant to double-strand breaks in the environment of a raised endonuclease activity. • Hybridization-based techniques are preferable for the analysis of damaged and/or oxidized genomic fragments, rather than the qRT-PCR method. • A chronic exposure to the low-dose IR induces an elevation of the rDNA content in the human circulating cfDNA as compared to cellular DNA. • An exposure to IR entails a decrease of the level of the human circulating satellite III (1q12) as compared to cellular DNA (RsatIII index). • The RrDNA/RsatIII ratio is a potential marker of a chronic IR individual exposure. - Abstract: A single exposure to ionizing radiation (IR) results in an elevated cell-free DNA (cfDNA) content in the blood plasma. In this case, the cfDNA concentration can be a marker of the cell death in the organism. However, a chronic exposure to a low-dose IR enhances both the endonuclease activity and titer of antibodies to DNA in blood plasma, resulting in a decrease of the total concentration of circulating cfDNA in exposed people. In this case, the total cfDNA concentration should not be considered as a marker of the cell death in an exposed body. We assumed that a pool of the cfDNA circulating in the exposed people contains DNA fragments, which are resistant to a double-strand break formation in the environment of the elevated plasma endonuclease activity, and can be accumulated in the blood plasma. In order to test this hypothesis, we studied the content of GC-rich sequences (69%GC) of the transcribed region of human ribosomal repeat (rDNA), as well as the content of AT-rich repeat (63%AT) of satellite III (1q12) in the cfDNA samples obtained from 285 individuals. We have found that a chronic exposure to gamma-neutron radiation (N = 88) and tritium β-radiation (N = 88) evokes an increase of the rDNA content (RrDNA index) and a decrease of the satellite III content (RsatIII index) in the

  11. Eleventh DOE workshop on personnel neutron dosimetry

    International Nuclear Information System (INIS)

    1991-01-01

    Since its formation, the Office of Health (EH-40) has stressed the importance of the exchange of information related to and improvements in neutron dosimetry. This Workshop was the eleventh in the series sponsored by the Department of Energy (DOE). It provided a forum for operational personnel at DOE facilities to discuss current issues related to neutron dosimetry and for leading investigators in the field to discuss promising approaches for future research. A total of 26 papers were presented including the keynote address by Dr. Warren K. Sinclair, who spoke on, ''The 1990 Recommendations of the ICRP and their Biological Background.'' The first several papers discussed difficulties in measuring neutrons of different energies and ways of compensating or deriving correction factors at individual facilities. Presentations were also given by the US Navy and Air Force. Current research in neutron dosimeter development was the subject of the largest number of papers. These included a number on the development of neutron spectrometers

  12. Hupa Numbers.

    Science.gov (United States)

    Bennett, Ruth, Ed.; And Others

    An introduction to the Hupa number system is provided in this workbook, one in a series of numerous materials developed to promote the use of the Hupa language. The book is written in English with Hupa terms used only for the names of numbers. The opening pages present the numbers from 1-10, giving the numeral, the Hupa word, the English word, and…

  13. Triangular Numbers

    Indian Academy of Sciences (India)

    Admin

    Triangular number, figurate num- ber, rangoli, Brahmagupta–Pell equation, Jacobi triple product identity. Figure 1. The first four triangular numbers. Left: Anuradha S Garge completed her PhD from. Pune University in 2008 under the supervision of Prof. S A Katre. Her research interests include K-theory and number theory.

  14. Proth Numbers

    Directory of Open Access Journals (Sweden)

    Schwarzweller Christoph

    2015-02-01

    Full Text Available In this article we introduce Proth numbers and prove two theorems on such numbers being prime [3]. We also give revised versions of Pocklington’s theorem and of the Legendre symbol. Finally, we prove Pepin’s theorem and that the fifth Fermat number is not prime.

  15. Occupational Pesticide Exposures and Respiratory Health

    Science.gov (United States)

    Ye, Ming; Beach, Jeremy; Martin, Jonathan W.; Senthilselvan, Ambikaipakan

    2013-01-01

    Pesticides have been widely used to control pest and pest-related diseases in agriculture, fishery, forestry and the food industry. In this review, we identify a number of respiratory symptoms and diseases that have been associated with occupational pesticide exposures. Impaired lung function has also been observed among people occupationally exposed to pesticides. There was strong evidence for an association between occupational pesticide exposure and asthma, especially in agricultural occupations. In addition, we found suggestive evidence for a link between occupational pesticide exposure and chronic bronchitis or COPD. There was inconclusive evidence for the association between occupational pesticide exposure and lung cancer. Better control of pesticide uses and enforcement of safety behaviors, such as using personal protection equipment (PPE) in the workplace, are critical for reducing the risk of developing pesticide-related symptoms and diseases. Educational training programs focusing on basic safety precautions and proper uses of personal protection equipment (PPE) are possible interventions that could be used to control the respiratory diseases associated with pesticide exposure in occupational setting. PMID:24287863

  16. X-ray and neutron scattering investigations of YCo3-H

    International Nuclear Information System (INIS)

    Benham, M.J.; Bennington, S.M.; Ross, D.K.; Noreus, D.; Yamaguchi, M.

    1989-01-01

    Various structural studies of YCo 3 H(D) x in the β-phase (0 2 . Neutron diffraction and inelastic neutron scattering were also used in tandem, and hydrogen occupation of a single (36i) tetrahedral site was inferred for the entire concentration range. (orig.)

  17. Occupational injuries due to violence.

    Science.gov (United States)

    Hales, T; Seligman, P J; Newman, S C; Timbrook, C L

    1988-06-01

    Each year in the United States, an estimated 800 to 1,400 people are murdered at work, and an unknown number of nonfatal injuries due to workplace violence occur. Based on Ohio's workers' compensation claims from 1983 through 1985, police officers, gasoline service station employees, employees of the real estate industry, and hotel/motel employees were found to be at the highest risk for occupational violent crime (OVC) injury and death. Grocery store employees, specifically those working in convenience food stores, and employees of the real estate industry had the most reported rapes. Four previously unidentified industries at increased risk of employee victimization were described. Identification of industries and occupations at high risk for crime victimization provides the opportunity to focus preventive strategies to promote employee safety and security in the workplace.

  18. [Occupational hazards and bladder cancer].

    Science.gov (United States)

    Nizamova, R S

    1991-01-01

    Occupational exposure to health hazards was studied in 258 industrial workers who had developed cancer of the bladder against 454 matched controls. All the test subjects and controls were residents of the Tambov Province centers of chemical industry. Statistical significance (relative risk-4.7) was established for exposure to aromatic amines. For those contacting with aniline dyes the relative risk (RR) made up 2.4. The risk to develop bladder cancer in powder shops (RR-3.2) was attributed to the hazards of dyes and diphenylamine. In leather-shoe and textile industry the exposure to dyes was not safe (RR-6.1), neither was it to chemicals, oil products, pesticides, overheating (RR-3.2, 1.6, 3.2 and 2.9, respectively). It is stated that in line with a significant risk to develop bladder cancer at exposure to aromatic amines there exist a number of occupational factors contributing to this risk.

  19. Evaluation of double differential yield as used for representation of neutron spectra

    International Nuclear Information System (INIS)

    Solieman, A.H.M.; Comsan, M.N.H.

    2002-01-01

    The neutron intensity for TOF spectra representation has, until now, only been expressed in terms of double differential yield; number of neutrons per unit charge per unit solid angle per unit neutron energy interval (i.e. neutron intensity at a given resolving power). For accelerator-based neutron sources, the double differential yield - in terms of neutron energy interval - is found to be affected by the kinematics of the neutron producing reaction, to produce intensity irrelevant spectra. The results affect not only the applications that depend on relative neutron intensities, but also the applications that depend on the neutron intensity-weighted integration of the neutron spectra (e.g. neutron average energy calculation, and dose calculation using kerma factors). Other definition of the double differential yield - in terms of projectile energy loss - is suggested to avoid the drawbacks of the old definition. The neutron spectra that are driven using the two definitions are discussed

  20. Sagan numbers

    OpenAIRE

    Mendonça, J. Ricardo G.

    2012-01-01

    We define a new class of numbers based on the first occurrence of certain patterns of zeros and ones in the expansion of irracional numbers in a given basis and call them Sagan numbers, since they were first mentioned, in a special case, by the North-american astronomer Carl E. Sagan in his science-fiction novel "Contact." Sagan numbers hold connections with a wealth of mathematical ideas. We describe some properties of the newly defined numbers and indicate directions for further amusement.

  1. Application of neutron activation analysis

    International Nuclear Information System (INIS)

    Dybczynski, R.

    2001-01-01

    The physical basis and analytical possibilities of neutron activation analysis have been performed. The number of applications in material engineering, geology, cosmology, oncology, criminology, biology, agriculture, environment protection, archaeology, history of art and especially in chemical analysis have been presented. The place of the method among other methods of inorganic quantitative chemical analysis for trace elements determination has been discussed

  2. Fundamental physics with low-energy neutrons

    International Nuclear Information System (INIS)

    Barrón-Palos, Libertad

    2016-01-01

    Low-energy neutrons are playing a prominent role in a growing number of fundamental physics studies. This paper provides a brief description of the physics that some of the experiments in the area are addressing. (paper)

  3. Personnel neutron dose assessment upgrade: Volume 1, Personnel neutron dosimetry assessment: [Final report

    International Nuclear Information System (INIS)

    Hadlock, D.E.; Brackenbush, L.W.; Griffith, R.V.; Hankins, D.E.; Parkhurst, M.A.; Stroud, C.M.; Faust, L.G.; Vallario, E.J.

    1988-07-01

    This report provides guidance on the characteristics, use, and calibration criteria for personnel neutron dosimeters. The report is applicable for neutrons with energies ranging from thermal to less than 20 MeV. Background for general neutron dosimetry requirements is provided, as is relevant federal regulations and other standards. The characteristics of personnel neutron dosimeters are discussed, with particular attention paid to passive neutron dosimetry systems. Two of the systems discussed are used at DOE and DOE-contractor facilities (nuclear track emulsion and thermoluminescent-albedo) and another (the combination TLD/TED) was recently developed. Topics discussed in the field applications of these dosimeters include their theory of operation, their processing, readout, and interpretation, and their advantages and disadvantages for field use. The procedures required for occupational neutron dosimetry are discussed, including radiation monitoring and the wearing of dosimeters, their exchange periods, dose equivalent evaluations, and the documenting of neutron exposures. The coverage of dosimeter testing, maintenance, and calibration includes guidance on the selection of calibration sources, the effects of irradiation geometries, lower limits of detectability, fading, frequency of calibration, spectrometry, and quality control. 49 refs., 6 figs., 8 tabs

  4. Neutrons individual monitoring: 18 years of experience

    International Nuclear Information System (INIS)

    Goncalves, Sergio Alves; Mauricio, Claudia Lucia de Pinho; Moura Junior, Jose; Martins, Marcelo Marques; Meira, Nilton Ferreira; Diz, Ricardo; Seda, Rosangela Pinto Guimaraes

    2002-01-01

    The Thermoluminescent Dosimetry Laboratory of the Departamento de Monitoracao Individual of the Instituto de Radioprotecao e Dosimetria (LDT/DEMIN/IRD) is the only one in Brazil that operates routinely a whole body external individual monitoring service for neutrons. An albedo type monitor is used with thermoluminescent detectors pairs of 6 LiF:Mg,Ti and 7 LiF:Mg,Ti, made by Harshaw/Bicron and named, respectively, TLD-600 and TLD-700. In its 18 years of activities, the laboratory has ever made a great effort to be continuously updated. Equipment and procedures have been updated and optimized in order to guarantee the quality of all measurements. Nowadays, the neutron individual monitoring service evaluates doses of about 300 workers occupationally exposed to neutrons in several facilities of different areas of Brazil. The system history and the results obtained by the service in international intercomparisons and in its routine monitoring are presented in this work. (author)

  5. Marketing occupational health care.

    Science.gov (United States)

    Norris, M J; Harris, J C

    1981-01-01

    A very basic part of marketing success is determining areas of your business in which you have a competitive advantage. In drafting a marketing plan for the Denver Clinic, the competitive advantages group practices have in the area of occupational health were quickly realized. This competitive edge is presented along with the Denver Clinic's marketing strategies and plans to capitalize on occupational healthcare advantages.

  6. The Heath Occupational Model.

    Science.gov (United States)

    Heath, William E.

    1990-01-01

    Career development programs must identify occupational needs of adults. A model based on Maslow's hierarchy develops occupational questions related to individual motivations (physiology, safety, love, esteem, and self-actualization). Individual needs are then compared with characteristics and benefits of proposed jobs, companies, or careers. (SK)

  7. Leadership and Occupational Stress

    Science.gov (United States)

    Stickle, Fred E.; Scott, Kelly

    2016-01-01

    In a leadership position, it is important to understand what stress is and how it affects others. In an occupational setting, stressors vary according to personality types, gender, and occupational rank. The purpose of this manuscript is to review the foundations of stress and to explore how personality characteristics influence stress.…

  8. Occupational Stress among Teachers.

    Science.gov (United States)

    Albertson, Larry M.; Kagan, Dona M.

    1987-01-01

    Two studies were conducted to investigate the degree to which occupational stress among teachers could be attributed to personal characteristics of the individuals themselves. The first study developed dispositional stress scales. The second examined correlations between these scales, occupational stress scales, and teachers' attitudes toward…

  9. CAUSES OF OCCUPATIONAL INJURIES

    NARCIS (Netherlands)

    KINGMA, J

    1994-01-01

    The causes of occupational injuries (N = 2,365) were investigated. Accidents with machinery and hand tools were the two main causes (49.9%). 89% of the patients with occupational injuries were male. The highest risk group were in the age category of 19 years or less (51.9%). This age group also

  10. Neutron matter, symmetry energy and neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Stefano, Gandolfi [Los Alamos National Laboratory (LANL); Steiner, Andrew W [ORNL

    2016-01-01

    Recent progress in quantum Monte Carlo with modern nucleon-nucleon interactions have enabled the successful description of properties of light nuclei and neutron-rich matter. Of particular interest is the nuclear symmetry energy, the energy cost of creating an isospin asymmetry, and its connection to the structure of neutron stars. Combining these advances with recent observations of neutron star masses and radii gives insight into the equation of state of neutron-rich matter near and above the saturation density. In particular, neutron star radius measurements constrain the derivative of the symmetry energy.

  11. Directional epithermal neutron detector

    International Nuclear Information System (INIS)

    Givens, W.W.; Mills, W.R. Jr.

    1986-01-01

    A borehole tool for epithermal neutron die-away logging of subterranean formations surrounding a borehole is described which consists of: (a) a pulsed source of fast neutrons for irradiating the formations surrounding a borehole, (b) at least one neutron counter for counting epithermal neutrons returning to the borehole from the irradiated formations, (c) a neutron moderating material, (d) an outer thermal neutron shield providing a housing for the counter and the moderating material, (e) an inner thermal neutron shield dividing the housing so as to provide a first compartment bounded by the inner thermal neutron shield and a first portion of the outer thermal neutron shield and a second compartment bounded by the inner thermal neutron shield and a second portion of the outer thermal neutron shield, the counter being positioned within the first compartment and the moderating material being positioned within the second compartment, and (f) means for positioning the borehole tool against one side of the borehole wall and azimuthally orienting the borehole tool such that the first chamber is in juxtaposition with the borehole wall, the formation epithermal neutrons penetrating into the first chamber through the first portion of the outer thermal neutron shield are detected by the neutron counter for die-away measurement, thereby maximizing the directional sensitivty of the neutron counter to formation epithermal neutrons, the borehole fluid epithermal neutrons penetrating into the second chamber through the second chamber through the second portion of the outer thermal neutron shield are largely slowed down and lowered in energy by the moderating material and absorbed by the inner thermal neutron shield before penetrating into the first chamber, thereby minimizing the directional sensitivity of the neutron counter to borehole fluid epithermal neutrons

  12. Occupational stress among dentists

    DEFF Research Database (Denmark)

    Moore, Rod

    2011-01-01

    Dentists report a high degree of occupational stress.(Cooper, Mallinger, and Kahn, 1978;Coster, Carstens, and Harris, 1987;DiMatteo, Shugars, and Hays, 1993;Hakeberg et al., 1992;Möller and Spangenberg, 1996;Moore, 2000;Myers and Myers, 2004;O'Shea, Corah, and Ayer, 1984) This chapter reviews...... the literature of studies that elaborate on the circumstances of occupational stress of dentists. These will include the frequency of occurrence of occupational stress among dentists in several countries, frequency and intensity of identified stressors specific to dentistry, as well as the consequences...... of this occupational stress. The literature on consequences includes effects on dentists' physical health, personal and occupational performance, including "burnout" phenomena, as well as topics of alcohol or substance abuse and reports of suicidal behaviour among dentists. One specific and less conventionally...

  13. Occupational skin diseases

    DEFF Research Database (Denmark)

    Mahler, V; Aalto-Korte, K; Alfonso, J H

    2017-01-01

    BACKGROUND: Work-related skin diseases (WSD) are caused or worsened by a professional activity. Occupational skin diseases (OSD) need to fulfil additional legal criteria which differ from country to country. OSD range amongst the five most frequently notified occupational diseases (musculoskeletal...... diseases, neurologic diseases, lung diseases, diseases of the sensory organs, skin diseases) in Europe. OBJECTIVE: To retrieve information and compare the current state of national frameworks and pathways to manage patients with occupational skin disease with regard to prevention, diagnosis, treatment...... in Science and Technology (COST) Action TD 1206 (StanDerm) (www.standerm.eu). RESULTS: Besides a national health service or a statutory health insurance, most European member states implemented a second insurance scheme specifically geared at occupational diseases [insurance against occupational risks...

  14. Occupational medicine and toxicology

    Directory of Open Access Journals (Sweden)

    Fischer Axel

    2006-02-01

    Full Text Available Abstract This editorial is to announce the Journal of Occupational Medicine and Toxicology, a new Open Access, peer-reviewed, online journal published by BioMed Central. Occupational medicine and toxicology belong to the most wide ranging disciplines of all medical specialties. The field is devoted to the diagnosis, prevention, management and scientific analysis of diseases from the fields of occupational and environmental medicine and toxicology. It also covers the promotion of occupational and environmental health. The complexity of modern industrial processes has dramatically changed over the past years and today's areas include effects of atmospheric pollution, carcinogenesis, biological monitoring, ergonomics, epidemiology, product safety and health promotion. We hope that the launch of the Journal of Occupational Medicine and Toxicology will aid in the advance of these important areas of research bringing together multi-disciplinary research findings.

  15. Powder neutron diffractometers

    International Nuclear Information System (INIS)

    Adib, M.

    2002-01-01

    Basic properties and applications of powder neutron Diffractometers are described for optimum use of the continuous neutron beams. These instruments are equipped with position sensitive detectors, neutron guide tubes, and both high intensity and high resolution modes of operation are possible .The principles of both direct and Fourier reverse time-of-flight neutron Diffractometers are also given

  16. Neutron dosimetry - A review

    Energy Technology Data Exchange (ETDEWEB)

    Baum, J W

    1955-03-29

    This review summarizes information on the following subjects: (1) physical processes of importance in neutron dosimetry; (2) biological effects of neutrons; (3) neutron sources; and (4) instruments and methods used in neutron dosimetry. Also, possible improvements in dosimetry instrumentation are outlined and discussed. (author)

  17. Neutron scattering. Lectures

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner [eds.

    2010-07-01

    The following topics are dealt with: Neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)

  18. Neutron generator control system

    International Nuclear Information System (INIS)

    Peelman, H.E.; Bridges, J.R.

    1981-01-01

    A method is described of controlling the neutron output of a neutron generator tube used in neutron well logging. The system operates by monitoring the target beam current and comparing a function of this current with a reference voltage level to develop a control signal used in a series regulator to control the replenisher current of the neutron generator tube. (U.K.)

  19. Genetic effect of neutrons

    International Nuclear Information System (INIS)

    Luchnik, N.V.; Sevan'kaev, A.V.; Fesenko, Eh.V.

    1984-01-01

    Gene mutations resulting from neutron effect are considered, but attention is focused on chromosome mutations. Dose curves for different energy of neutrons obtained at different objects are obtained which makes it possible to consider RBE of neutrons depending on their energy and radiation dose and to get some information on the neutron effect on heredity

  20. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2010-01-01

    The following topics are dealt with: Neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)

  1. Eulerian numbers

    CERN Document Server

    Petersen, T Kyle

    2015-01-01

    This text presents the Eulerian numbers in the context of modern enumerative, algebraic, and geometric combinatorics. The book first studies Eulerian numbers from a purely combinatorial point of view, then embarks on a tour of how these numbers arise in the study of hyperplane arrangements, polytopes, and simplicial complexes. Some topics include a thorough discussion of gamma-nonnegativity and real-rootedness for Eulerian polynomials, as well as the weak order and the shard intersection order of the symmetric group. The book also includes a parallel story of Catalan combinatorics, wherein the Eulerian numbers are replaced with Narayana numbers. Again there is a progression from combinatorics to geometry, including discussion of the associahedron and the lattice of noncrossing partitions. The final chapters discuss how both the Eulerian and Narayana numbers have analogues in any finite Coxeter group, with many of the same enumerative and geometric properties. There are four supplemental chapters throughout, ...

  2. Neutronics of pulsed spallation neutron sources

    International Nuclear Information System (INIS)

    Watanabe, Noboru

    2003-01-01

    Various topics and issues on the neutronics of pulsed spallation neutron sources, mainly for neutron scattering experiments, are reviewed to give a wide circle of readers a better understanding of these sources in order to achieve a high neutronic performance. Starting from what neutrons are needed, what the spallation reaction is and how to produce slow-neutrons more efficiently, the outline of the target and moderator neutronics are explained. Various efforts with some new concepts or ideas have already been devoted to obtaining the highest possible slow-neutron intensity with desired pulse characteristics. This paper also reviews the recent progress of such efforts, mainly focused on moderator neutronics, since moderators are the final devices of a neutron source, which determine the source performance. Various governing parameters for neutron-pulse characteristics such as material issues, geometrical parameters (shape and dimensions), the target-moderator coupling scheme, the ortho-para-hydrogen ratio, poisoning, etc are discussed, aiming at a high performance pulsed spallation source

  3. Neutron shieldings

    International Nuclear Information System (INIS)

    Tarutani, Kohei

    1979-01-01

    Purpose: To decrease the stresses resulted by the core bendings to the base of an entrance nozzle. Constitution: Three types of round shielding rods of different diameter are arranged in a hexagonal tube. The hexagonal tube is provided with several spacer pads receiving the loads from the core constrain mechanism at its outer circumference, a handling head for a fuel exchanger at its top and an entrance nozzle for self-holding the neutron shieldings and flowing heat-removing coolants at its bottom. The diameters for R 1 , R 2 and R 3 for the round shielding rods are designed as: 0.1 R 1 2 1 and 0.2 R 1 2 1 . Since a plurality of shielding rods of small diameter are provided, soft structure are obtained and a plurality of coolant paths are formed. (Furukawa, Y.)

  4. Neutron Generators for Spent Fuel Assay

    International Nuclear Information System (INIS)

    Ludewigt, Bernhard A.

    2010-01-01

    The Next Generation Safeguards Initiative (NGSI) of the U.S. DOE has initiated a multi-lab/university collaboration to quantify the plutonium (Pu) mass in, and detect the diversion of pins from, spent nuclear fuel (SNF) assemblies with non-destructive assay (NDA). The 14 NDA techniques being studied include several that require an external neutron source: Delayed Neutrons (DN), Differential Die-Away (DDA), Delayed Gammas (DG), and Lead Slowing-Down Spectroscopy (LSDS). This report provides a survey of currently available neutron sources and their underlying technology that may be suitable for NDA of SNF assemblies. The neutron sources considered here fall into two broad categories. The term 'neutron generator' is commonly used for sealed devices that operate at relatively low acceleration voltages of less than 150 kV. Systems that employ an acceleration structure to produce ion beam energies from hundreds of keV to several MeV, and that are pumped down to vacuum during operation, rather than being sealed units, are usually referred to as 'accelerator-driven neutron sources.' Currently available neutron sources and future options are evaluated within the parameter space of the neutron generator/source requirements as currently understood and summarized in section 2. Applicable neutron source technologies are described in section 3. Commercially available neutron generators and other source options that could be made available in the near future with some further development and customization are discussed in sections 4 and 5, respectively. The pros and cons of the various options and possible ways forward are discussed in section 6. Selection of the best approach must take a number of parameters into account including cost, size, lifetime, and power consumption, as well as neutron flux, neutron energy spectrum, and pulse structure that satisfy the requirements of the NDA instrument to be built.

  5. The Occupations of Literacy: Occupational Therapy's Role

    Science.gov (United States)

    Frolek Clark, Gloria

    2016-01-01

    Nationally, student proficiency in reading and writing is very low and requires ongoing focus from state and local agencies. With almost 25% of occupational therapists working in early intervention and school settings (AOTA, 2015), their role of facilitating literacy (e.g., reading, writing, speaking and listening) is critical. Occupational…

  6. TREAT neutron-radiography facility

    International Nuclear Information System (INIS)

    Harrison, L.J.

    1981-01-01

    The TREAT reactor was built as a transient irradiation test reactor. By taking advantage of built-in system features, it was possible to add a neutron-radiography facility. This facility has been used over the years to radiograph a wide variety and large number of preirradiated fuel pins in many different configurations. Eight different specimen handling casks weighing up to 54.4 t (60 T) can be accommodated. Thermal, epithermal, and track-etch radiographs have been taken. Neutron-radiography service can be provided for specimens from other reactor facilities, and the capacity for storing preirradiated specimens also exists

  7. Conducting Polymers for Neutron Detection

    International Nuclear Information System (INIS)

    Clare Kimblin; Kirk Miller; Bob Vogel; Bill Quam; Harry McHugh; Glen Anthony; Steve Jones; Mike Grover

    2007-01-01

    Conjugated polymers have emerged as an attractive technology for large-area electronic applications. As organic semiconductors, they can be used to make large-area arrays of diodes or transistors using fabrication techniques developed for polymer coatings, such as spraying and screen-printing. We have demonstrated both neutron and alpha detection using diodes made from conjugated polymers and have done preliminary work to integrate a boron carbide layer into the conventional polymer device structure to capture thermal neutrons. The polymer devices appear to be insensitive to gamma rays, due to their small physical thickness and low atomic number

  8. Miscellaneous neutron techniques

    International Nuclear Information System (INIS)

    Iddings, F.A.

    1976-01-01

    Attention is brought to the less often uses of neutrons in the areas of neutron radiography, well logging, and neutron gaging. Emphasis on neutron radiography points toward the isotopic sensitivity of the method versus the classical bulk applications. Also recognized is the ability of neutron radiography to produce image changes that correspond to thickness and density changes obtained in photon radiography. Similarly, neutron gaging applications center on the measurement of radiography. Similarly, neutron gaging applications center on the measurement of water, oil, or plastics in industrial samples. Well logging extends the neutron gaging to encompass many neutron properties and reactions besides thermalization and capture. Neutron gaging also gives information on organic structure and concentrations of a variety of elements or specific compounds in selected matrices

  9. Nuclear reactor neutron shielding

    Science.gov (United States)

    Speaker, Daniel P; Neeley, Gary W; Inman, James B

    2017-09-12

    A nuclear reactor includes a reactor pressure vessel and a nuclear reactor core comprising fissile material disposed in a lower portion of the reactor pressure vessel. The lower portion of the reactor pressure vessel is disposed in a reactor cavity. An annular neutron stop is located at an elevation above the uppermost elevation of the nuclear reactor core. The annular neutron stop comprises neutron absorbing material filling an annular gap between the reactor pressure vessel and the wall of the reactor cavity. The annular neutron stop may comprise an outer neutron stop ring attached to the wall of the reactor cavity, and an inner neutron stop ring attached to the reactor pressure vessel. An excore instrument guide tube penetrates through the annular neutron stop, and a neutron plug comprising neutron absorbing material is disposed in the tube at the penetration through the neutron stop.

  10. Health physics considerations at a neutron therapy facility cyclotron

    International Nuclear Information System (INIS)

    Kleck, J.H.; Krueger, D.J.; Mc Laughlin, J.E.; Smathers, J.B.

    1987-01-01

    The U.C.L.A. Neutron Therapy Facility (NTF) is one of four such facilities in the United States currently involved in NCI sponsored trials of neutron therapy and reflects the present interest in the use of high energy neutron beams for treating certain types of human cancers. The NTF houses a CP-45 negative ion cyclotron which accelerates a 46 MeV proton beam for production of neutrons from a beryllium target. In addition to patient treatment, the NTF is involved in the production of positron emitting radioisotopes for diagnostic use in Positron Emission Tomography (PET). The activation of therapy treatment collimators, positron and neutron target systems, and a high and rapidly varying external radiation environment in a clinical setting have contributed to the need for a comprehensive radiation control program in which patient care is balanced with the maintenance of occupational exposures to ALARA levels

  11. Heat capacity of the neutron star inner crust within an extended nuclear statistical equilibrium model

    Science.gov (United States)

    Burrello, S.; Gulminelli, F.; Aymard, F.; Colonna, M.; Raduta, Ad. R.

    2015-11-01

    Background: Superfluidity in the crust is a key ingredient for the cooling properties of proto-neutron stars. Present theoretical calculations employ the quasiparticle mean-field Hartree-Fock-Bogoliubov theory with temperature-dependent occupation numbers for the quasiparticle states. Purpose: Finite temperature stellar matter is characterized by a whole distribution of different nuclear species. We want to assess the importance of this distribution on the calculation of heat capacity in the inner crust. Method: Following a recent work, the Wigner-Seitz cell is mapped into a model with cluster degrees of freedom. The finite temperature distribution is then given by a statistical collection of Wigner-Seitz cells. We additionally introduce pairing correlations in the local density BCS approximation both in the homogeneous unbound neutron component, and in the interface region between clusters and neutrons. Results: The heat capacity is calculated in the different baryonic density conditions corresponding to the inner crust, and in a temperature range varying from 100 KeV to 2 MeV. We show that accounting for the cluster distribution has a small effect at intermediate densities, but it considerably affects the heat capacity both close to the outer crust and close to the core. We additionally show that it is very important to consider the temperature evolution of the proton fraction for a quantitatively reliable estimation of the heat capacity. Conclusions: We present the first modelization of stellar matter containing at the same time a statistical distribution of clusters at finite temperature, and pairing correlations in the unbound neutron component. The effect of the nuclear distribution on the superfluid properties can be easily added in future calculations of the neutron star cooling curves. A strong influence of resonance population on the heat capacity at high temperature is observed, which deserves to be further studied within more microscopic calculations.

  12. Accelerator driven reactors, - the significance of the energy distribution of spallation neutrons on the neutron statistics

    Energy Technology Data Exchange (ETDEWEB)

    Fhager, V

    2000-01-01

    In order to make correct predictions of the second moment of statistical nuclear variables, such as the number of fissions and the number of thermalized neutrons, the dependence of the energy distribution of the source particles on their number should be considered. It has been pointed out recently that neglecting this number dependence in accelerator driven systems might result in bad estimates of the second moment, and this paper contains qualitative and quantitative estimates of the size of these efforts. We walk towards the requested results in two steps. First, models of the number dependent energy distributions of the neutrons that are ejected in the spallation reactions are constructed, both by simple assumptions and by extracting energy distributions of spallation neutrons from a high-energy particle transport code. Then, the second moment of nuclear variables in a sub-critical reactor, into which spallation neutrons are injected, is calculated. The results from second moment calculations using number dependent energy distributions for the source neutrons are compared to those where only the average energy distribution is used. Two physical models are employed to simulate the neutron transport in the reactor. One is analytical, treating only slowing down of neutrons by elastic scattering in the core material. For this model, equations are written down and solved for the second moment of thermalized neutrons that include the distribution of energy of the spallation neutrons. The other model utilizes Monte Carlo methods for tracking the source neutrons as they travel inside the reactor material. Fast and thermal fission reactions are considered, as well as neutron capture and elastic scattering, and the second moment of the number of fissions, the number of neutrons that leaked out of the system, etc. are calculated. Both models use a cylindrical core with a homogenous mixture of core material. Our results indicate that the number dependence of the energy

  13. Accelerator driven reactors, - the significance of the energy distribution of spallation neutrons on the neutron statistics

    International Nuclear Information System (INIS)

    Fhager, V.

    2000-01-01

    In order to make correct predictions of the second moment of statistical nuclear variables, such as the number of fissions and the number of thermalized neutrons, the dependence of the energy distribution of the source particles on their number should be considered. It has been pointed out recently that neglecting this number dependence in accelerator driven systems might result in bad estimates of the second moment, and this paper contains qualitative and quantitative estimates of the size of these efforts. We walk towards the requested results in two steps. First, models of the number dependent energy distributions of the neutrons that are ejected in the spallation reactions are constructed, both by simple assumptions and by extracting energy distributions of spallation neutrons from a high-energy particle transport code. Then, the second moment of nuclear variables in a sub-critical reactor, into which spallation neutrons are injected, is calculated. The results from second moment calculations using number dependent energy distributions for the source neutrons are compared to those where only the average energy distribution is used. Two physical models are employed to simulate the neutron transport in the reactor. One is analytical, treating only slowing down of neutrons by elastic scattering in the core material. For this model, equations are written down and solved for the second moment of thermalized neutrons that include the distribution of energy of the spallation neutrons. The other model utilizes Monte Carlo methods for tracking the source neutrons as they travel inside the reactor material. Fast and thermal fission reactions are considered, as well as neutron capture and elastic scattering, and the second moment of the number of fissions, the number of neutrons that leaked out of the system, etc. are calculated. Both models use a cylindrical core with a homogenous mixture of core material. Our results indicate that the number dependence of the energy

  14. Industrial distributions of severe occupational injuries among workers in Thailand.

    Science.gov (United States)

    Yamakawa, Michiyo; Sithisarankul, Pornchai; Yorifuji, Takashi; Hengpraprom, Sarunya; Hiransuthikul, Narin; Doi, Hiroyuki; Takao, Soshi

    2014-01-01

    In industrializing countries, occupational safety and health have been affected by globalization. However, a lack of reliable data prevents evaluation of this situation. Therefore, we examined industrial distributions and risks of severe occupational injuries among workers in Thailand, which is one of the few industrializing countries that compiles nationwide data. Data on workers who made claims for occupational injuries from 2007 to 2009 were extracted from the Workmen's Compensation Fund records in Thailand. Among 501,334 claimants, we evaluated the industrial distributions of severe occupational injuries (i.e., permanent disability and death). We then examined the associations between industry and those injuries, using proportionate ratios (PRs) between each industrial category and the overall distribution of occupational injuries. The number of workers in manufacturing making claims for severe occupational injuries was the largest among all industrial categories (319,114/501,334 injuries), although the total number of occupational injuries recently declined. Additionally, workers in manufacturing experienced severe occupational injuries more often compared with the overall distribution of occupational injuries. The PRs (95% confidence interval) for manufacturing were 1.17 (1.14-1.20) in men and 1.33 (1.27-1.38) in women. After adjusting for individual characteristics, the results did not substantially change. Manufacturing seems to have the largest burden of occupational injuries in industrializing countries like Thailand.

  15. Transfinite Numbers

    Indian Academy of Sciences (India)

    Transfinite Numbers. What is Infinity? S M Srivastava. In a series of revolutionary articles written during the last quarter of the nineteenth century, the great Ger- man mathematician Georg Cantor removed the age-old mistrust of infinity and created an exceptionally beau- tiful and useful theory of transfinite numbers. This is.

  16. Martian Neutron Energy Spectrometer (MANES)

    Science.gov (United States)

    Maurer, R. H.; Roth, D. R.; Kinnison, J. D.; Goldsten, J. O.; Fainchtein, R.; Badhwar, G.

    2000-01-01

    High energy charged particles of extragalactic, galactic, and solar origin collide with spacecraft structures and planetary atmospheres. These primaries create a number of secondary particles inside the structures or on the surfaces of planets to produce a significant radiation environment. This radiation is a threat to long term inhabitants and travelers for interplanetary missions and produces an increased risk of carcinogenesis, central nervous system (CNS) and DNA damage. Charged particles are readily detected; but, neutrons, being electrically neutral, are much more difficult to monitor. These secondary neutrons are reported to contribute 30-60% of the dose equivalent in the Shuttle and MIR station. The Martian atmosphere has an areal density of 37 g/sq cm primarily of carbon dioxide molecules. This shallow atmosphere presents fewer mean free paths to the bombarding cosmic rays and solar particles. The secondary neutrons present at the surface of Mars will have undergone fewer generations of collisions and have higher energies than at sea level on Earth. Albedo neutrons produced by collisions with the Martian surface material will also contribute to the radiation environment. The increased threat of radiation damage to humans on Mars occurs when neutrons of higher mean energy traverse the thin, dry Martian atmosphere and encounter water in the astronaut's body. Water, being hydrogeneous, efficiently moderates the high energy neutrons thereby slowing them as they penetrate deeply into the body. Consequently, greater radiation doses can be deposited in or near critical organs such as the liver or spleen than is the case on Earth. A second significant threat is the possibility of a high energy heavy ion or neutron causing a DNA double strand break in a single strike.

  17. Study on a model for future occupational health: proposal for an occupational health service model in Japan.

    Science.gov (United States)

    Higashi, Toshiaki

    2006-10-01

    The Study Model for Future Occupational Health (funded by a research grant from the Ministry of Health, Welfare and Labor) is a joint research project involving various organizations and agencies undertaken from 2002 to 2004. Society has undergone a dramatic transformation due to technological developments and internationalization. At the same time a low birth rate and an aging population have resulted in an increase in both the percentage of workers experiencing strong anxiety and stress in relation to their jobs and the working environment and the number of suicides. As a natural consequence, occupational health services are now expected to provide EAP, consulting and other functions that were formerly considered outside the realm of occupational health. In consideration of this background, the present study propose the following issues to provide a model for future occupational health services that meet the conditions presently confronted by each worker. 1. How to provide occupational health services and occupational physicians' services: 1) a basic time of 20 minutes of occupational health services per year should be allotted to each worker and to all workers; 2) the obligatory regulations should be revised to expand the obligation from businesses each with 50 or more employees under the present laws to businesses each with 30 or more employees. 2. Providers of occupational health services and occupational physicians' services: (1) reinforcement of outside occupational health agencies; (2) fostering occupational health consultant firms; (3) development of an institute of occupational safety and health; (4) support of activities by authorized occupational physicians in the field; (5) expanding of joint selection of occupational physicians including subsidy increase and the extension of a period of subsidy to five hears; (6) licensing of new entry into occupational health undertaking. 3. Introduction of new report system: (1) establishment of the obligation to

  18. Rearrangement of valence neutrons in the neutrinoless double-β decay of 136Xe

    Science.gov (United States)

    Szwec, S. V.; Kay, B. P.; Cocolios, T. E.; Entwisle, J. P.; Freeman, S. J.; Gaffney, L. P.; Guimarães, V.; Hammache, F.; McKee, P. P.; Parr, E.; Portail, C.; Schiffer, J. P.; de Séréville, N.; Sharp, D. K.; Smith, J. F.; Stefan, I.

    2016-11-01

    A quantitative description of the change in ground-state neutron occupancies between 136Xe and 136Ba, the initial and final state in the neutrinoless double-β decay of 136Xe, has been extracted from precision measurements of the cross sections of single-neutron-adding and -removing reactions. Comparisons are made to recent theoretical calculations of the same properties using various nuclear-structure models. These are the same calculations used to determine the magnitude of the nuclear matrix elements for the process, which at present disagree with each other by factors of 2 or 3. The experimental neutron occupancies show some disagreement with the theoretical calculations.

  19. Neutron metrology file NMF-90. An integrated database for performing neutron spectrum adjustment calculations

    International Nuclear Information System (INIS)

    Kocherov, N.P.

    1996-01-01

    The Neutron Metrology File NMF-90 is an integrated database for performing neutron spectrum adjustment (unfolding) calculations. It contains 4 different adjustment codes, the dosimetry reaction cross-section library IRDF-90/NMF-G with covariances files, 6 input data sets for reactor benchmark neutron fields and a number of utility codes for processing and plotting the input and output data. The package consists of 9 PC HD diskettes and manuals for the codes. It is distributed by the Nuclear Data Section of the IAEA on request free of charge. About 10 MB of diskspace is needed to install and run a typical reactor neutron dosimetry unfolding problem. (author). 8 refs

  20. First delayed neutron emission measurements at ALTO with the neutron detector TETRA

    International Nuclear Information System (INIS)

    Testov, D.; Ancelin, S.; Bettane, J.; Ibrahim, F.; Kolos, K.; Mavilla, G.; Niikura, M.; Verney, D.; Wilson, J.; Kuznetsova, E.; Penionzhkevich, Yu.; Smirnov, V.; Sokol, E.

    2013-01-01

    Beta-decay properties are among the easiest and, therefore, the first ones to be measured to study new neutron-rich isotopes. Eventually, a very small number of nuclei could be sufficient to estimate their lifetime and neutron emission probability. With the new radioactive beam facilities which have been commissioned recently (or will be constructed shortly) new areas of neutron-rich isotopes will become reachable. To study beta-decay properties of such nuclei at IPN (Orsay) in the framework of collaboration with JINR (Dubna), a new experimental setup including the neutron detector of high efficiency TETRA was developed and commissioned

  1. neutron radiography. Report prepared from contributions by members of the MOD Working Party on Neutron Radiography

    International Nuclear Information System (INIS)

    Halmshaw, R.

    1977-03-01

    Radiography with thermal or cold neutrons has some special advantages over X-rays and gamma rays, and some facilities for neutron radiography exist in the Ministry of Defence. This report gives a brief and simple description of the technique, its advantages and disadvantages, and is illustrated with a number of Ordnance applications taken from MOD work, to show examples where neutron radiographs provided extra important information not available from X- or gamma radiography. The facilities available in the UK for neutron radiography are listed. (author)

  2. Neutron shielding performance of water-extended polyester

    International Nuclear Information System (INIS)

    Vega Carrillo, H.R.; Manzanares-Acuna, E.; Hernandez-Davila, V.M.; Vega Carrillo, H.R.; Hernandez-Davila, V.M.; Gallego, E.; Lorente, A.

    2006-01-01

    A Monte Carlo study to determine the shielding features to neutrons of water-extended polyester (WEP) was carried out. Materials with low atomic number are predominantly used for neutron shielding because these materials effectively attenuate neutrons, mainly through elastic and inelastic collisions. In addition to neutron attenuation properties, other desirable properties for neutron shielding materials include mechanical strength, stability, low cost, and ease of handling. During the selection of materials to design a neutron shield, prompt gamma production as well as radionuclide induced by neutron activation must be considered. In this investigation the Monte Carlo method (MCNP code) was used to evaluate the performance of a water-extended polyester shield designed for the transportation, storage, and use of a 252 Cf isotopic neutron source, for comparison the calculations were extended to water shielding, the bare source in vacuum and in air. (authors)

  3. Neutron shielding performance of water-extended polyester

    International Nuclear Information System (INIS)

    Vega Carrillo, H.R.; Manzanares-Acuna, E.; Hernandez-Davila, V.M.; Vega Carrillo, H.R.; Gallegoc, E.; Lorentec, A.; Hernandez-Davila, V.M.

    2006-01-01

    A Monte Carlo study to determine the shielding features to neutrons of water-extended polyester was carried out. Materials with low atomic number are predominantly used for neutron shielding because these materials effectively attenuate neutrons, mainly through elastic and inelastic collisions. In addition to neutron attenuation properties, other desirable properties for neutron shielding materials include mechanical strength, stability, low cost, and ease of handling. During the selection of materials to design a neutron shield, prompt gamma production as well as radionuclide induced by neutron activation must be considered. In this investigation the Monte Carlo method (M.C.N.P. code) was used to evaluate the performance of a water-extended polyester shield designed for the transportation, storage, and use of a 252 Cf isotopic neutron source, for comparison the calculations were extended to water shielding, the bare source in vacuum and in air. (authors)

  4. Neutron shielding performance of water-extended polyester

    Energy Technology Data Exchange (ETDEWEB)

    Vega Carrillo, H.R.; Manzanares-Acuna, E.; Hernandez-Davila, V.M. [Zacatecas Univ. Autonoma, Nuclear Studies (Mexico); Vega Carrillo, H.R.; Hernandez-Davila, V.M. [Zacatecas Univ. Autonoma, Electric Engineering Academic Units (Mexico); Gallego, E.; Lorente, A. [Madrid Univ. Politecnica, cNuclear Engineering Department (Mexico)

    2006-07-01

    A Monte Carlo study to determine the shielding features to neutrons of water-extended polyester (WEP) was carried out. Materials with low atomic number are predominantly used for neutron shielding because these materials effectively attenuate neutrons, mainly through elastic and inelastic collisions. In addition to neutron attenuation properties, other desirable properties for neutron shielding materials include mechanical strength, stability, low cost, and ease of handling. During the selection of materials to design a neutron shield, prompt gamma production as well as radionuclide induced by neutron activation must be considered. In this investigation the Monte Carlo method (MCNP code) was used to evaluate the performance of a water-extended polyester shield designed for the transportation, storage, and use of a {sup 252}Cf isotopic neutron source, for comparison the calculations were extended to water shielding, the bare source in vacuum and in air. (authors)

  5. Elements and process for recording direct image neutron radiographs

    International Nuclear Information System (INIS)

    Poignant, R.V. Jr.; Przybylowicz, E.P.

    1975-01-01

    An element is provided for recording a direct image neutron radiograph, thus eliminating the need for a transfer step (i.e., the use of a transfer screen). The element is capable of holding an electrostatic charge and comprises a first layer for absorbing neutrons and generating a current by dissipation of said electrostatic charge in proportion to the number of neutrons absorbed, and a second layer for conducting the current generated by the absorbed neutrons, said neutron absorbing layer comprising an insulative layer comprising neutron absorbing agents in a concentration of at least 10 17 atoms per cm 3 . An element for enhancing the effect of the neutron beam by utilizing the secondary emanations of neutron absorbing materials is also disclosed along with a process for using the device. (U.S.)

  6. Production and applications of neutrons using particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Chichester, David L. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2009-11-01

    Advances in neutron science have gone hand in hand with the development and of particle accelerators from the beginning of both fields of study. Early accelerator systems were developed simply to produce neutrons, allowing scientists to study their properties and how neutrons interact in matter, but people quickly realized that more tangible uses existed too. Today the diversity of applications for industrial accelerator-based neutron sources is high and so to is the actual number of instruments in daily use is high, and they serve important roles in the fields where they're used. This chapter presents a technical introduction to the different ways particle accelerators are used to produce neutrons, an historical overview of the early development of neutron-producing particle accelerators, a description of some current industrial accelerator systems, narratives of the fields where neutron-producing particle accelerators are used today, and comments on future trends in the industrial uses of neutron producing particle accelerators.

  7. Prompt gamma neutron activation analysis

    International Nuclear Information System (INIS)

    Goswami, A.

    2003-01-01

    Prompt gamma neutron activation analysis (PGNAA) is a technique for the analysis of elements present in solid, liquid and gaseous samples by measuring the capture gamma rays emitted from the sample during neutron irradiation. The technique is complementary to conventional neutron activation analysis (NAA) as it can be used in number of cases where NAA fails. Though the technique was first used in sixties, the advantage of the technique was first highlighted by Lindstrom and Anderson. PGNAA is increasingly being used as a rapid, instrumental, nondestructive and multielement analysis technique. A monograph and several excellent reviews on this topic have appeared recently. In this review, an attempt has been made to bring out the essential aspects of the technique, experimental arrangement and instrumentation involved, and areas of application. Some of the results will also be presented

  8. Occupational health in Central America.

    Science.gov (United States)

    Wesseling, Catharina; Aragón, Aurora; Morgado, Hugo; Elgstrand, Kaj; Hogstedt, Christer; Partanen, Timo

    2002-01-01

    The 12.4 million economically active population (EAP) of the seven Central American countries includes a large informal sector. Social security covers only 14-60%. No surveillance of occupational safety and health (OSH) hazards or accidents exists. Extrapolating the incidence of occupational accidents among insured Costa Rican workers to the Central American EAP yields two million accidents yearly, still a gross underestimate. Occupational diseases are underreported, misdiagnosed, and not recognized as such. A number of regional OSH programs aim at modernization of the labor administrations and address the formal sector, in particular textile maquila, in connection with free trade agreements. The weak role of the ministries of health is expected to strengthen under the Pan American Health Organization OSH program. Employers largely influence new policies. Workers' influence on OSH policies has been weak, with only about 10% unionization rate and scarce resources and OSH knowledge. Informal workers, however, are getting organized. OSH research is underdeveloped and not linked to policy making. Construction, agriculture, and general un/underemployment are considered priorities for intervention. The informal sector needs to be included in national and regional OSH policies. Regional collaboration and international development support are of strategic importance to achieve sustainable improvement in OSH.

  9. Occupational skin cancers

    Energy Technology Data Exchange (ETDEWEB)

    Gawkrodger, D.J. [Royal Hallamshire Hospital, Sheffield (United Kingdom). Dept. of Dermatology

    2004-10-01

    Skin cancer due to occupation is more common than is generally recognized, although it is difficult to obtain an accurate estimate of its prevalence. Over the past two centuries, occupational skin cancers have particularly been due to industrial exposure of men (it seems more so than women) to chemical carcinogens such as polycyclic hydrocarbons (e.g. from coal tar products) or to arsenic. Industrial processes have improved in most Western countries to limit this type of exposure, but those with outdoor occupations are still exposed to solar ultraviolet irradiation without this being widely recognized as an industrial hazard. Ionizing radiation such as X-rays can also cause skin cancer. Occupational skin cancers often resemble skin tumours found in non-occupational subjects, e.g. basal cell carcinoma, squamous cell carcinoma and malignant melanoma, but some pre-malignant lesions can be more specific and point to an occupational origin, e.g. tar keratoses or arsenical keratoses. An uncommon but well-recognized cause of occupational skin cancer is that which results from scar formation following an industrial burn. In the future it will be necessary to focus on preventative measures, e.g. for outdoor workers, the need to cover up in the sun and use sun protective creams and a campaign for earlier recognition of skin cancers, which are usually curable if treated in their early stages.

  10. BURNOUT AND OCCUPATIONAL PARTICIPATION

    Science.gov (United States)

    Eren, Hakan; Huri, Meral; Bağış, Nilsun; Başıbüyük, Onur; Şahin, Sedef; Umaroğlu, Mutlu; Orhan, Kaan

    2016-11-01

    The aim of the present study was to investigate the prevalence of burnout and occupational participation limitation among dental students in a dental school in Turkey. Four hundred fifty-eight dental students (females=153; males=305) were included in the study. The age range varied from 17-to-38 years. Maslach Burnout Inventory-Student Version (MBI-SV) and Canadian Occupational Performance Measure (COPM) were used to gather data. Descriptive analyses, t-test, and Kruskall-Wallis test for independent groups were used for data analyses. The results indicated that 26% of all the students have burnout in terms of emotional exhaustion (25%), cynicism (18%), and academic efficacy (14%). The results showed that burnout is statistically significant in relation to demographics (pstudents showed considerably decreased occupational performance and satisfaction scores, which suggested occupational participation limitations. Occupational performance and satisfaction scores were inversely correlated with emotional exhaustion and cynicism, while directly correlated with reduced academic efficacy (pburnout and occupational participation limitation can be seen among dental students. Students with burnout may also have occupational participation limitation. Enriching dental education programs with different psychological strategies may be useful for education of healthy dentists and improve the quality of oral and dental health services.

  11. Neutron flux monitor

    International Nuclear Information System (INIS)

    Seki, Eiji; Tai, Ichiro.

    1984-01-01

    Purpose: To maintain the measuring accuracy and the reponse time within an allowable range in accordance with the change of neutron fluxes in a nuclear reactor pressure vessel. Constitution: Neutron fluxes within a nuclear reactor pressure vessel are detected by detectors, converted into pulse signals and amplified in a range switching amplifier. The amplified signals are further converted through an A/D converter and digital signals from the converter are subjected to a square operation in an square operation circuit. The output from the circuit is inputted into an integration circuit to selectively accumulate the constant of 1/2n, 1 - 1/2n (n is a positive integer) respectively for two continuing signals to perform weighing. Then, the addition is carried out to calculate the integrated value and the addition number is changed by the chane in the number n to vary the integrating time. The integrated value is inputted into a control circuit to control the value of n so that the fluctuation and the calculation time for the integrated value are within a predetermined range and, at the same time, the gain of the range switching amplifier is controlled. (Seki, T.)

  12. Neutronic study of spherical cold-neutron sources composed of liquid hydrogen and liquid deuterium

    CERN Document Server

    Matsuo, Y; Nagaya, Y

    2003-01-01

    Using the cross-section model for neutron scattering in liquid H sub 2 and D sub 2 , a neutron transport analysis is performed for spherical cold-neutron sources composed of either para H sub 2 , normal H sub 2 or normal D sub 2. A special effort is made to generate a set of energy-averaged cross-sections (80 group constants between 0.1 mu eV and 10 eV) for liquid H sub 2 and D sub 2 at melting and boiling points. A number of conclusions on the spherical cold-neutron source configurations are drawn. It is especially shown that the highest cold-neutron flux is obtainable from the normal D sub 2 source with a radius of about 50 cm, while the normal- and para-H sub 2 sources with radii around 3-4 cm produce maximum cold-neutron fluxes at the center.

  13. The representation of neutron polarization

    International Nuclear Information System (INIS)

    Byrne, J.

    1979-01-01

    Neutron beam polarization representation is discussed under the headings; transfer matrices, coherent parity violation for neutrons, neutron spin rotation in helical magnetic fields, polarization and interference. (UK)

  14. Neutron irradiation of seeds 2

    Energy Technology Data Exchange (ETDEWEB)

    1968-10-01

    The irradiation of seeds with the fast neutron of research reactors has been hampered by difficulties in accurately measuring dose and in obtaining repeatable and comparable results. Co-ordinated research under an international program organized by the FAO and IAEA has already resulted in significant improvements in methods of exposing seeds in research reactors and in obtaining accurate dosimetry. This has been accomplished by the development of a standard reactor facility for the neutron irradiation of seeds and standard methods for determining fast-neutron dose and the biological response after irradiation. In this program various divisions of the IAEA and the Joint FAO/IAEA Division co-operate with a number of research institutes and reactor centres throughout the world. Results of the preliminary experiments were reported in Technical Reports Series No. 76, ''Neutron Irradiation of Seeds''. This volume contains the proceedings of a meeting of co-operators in the FAO/IAEA Neutron Seed Irradiation Program and other active scientists in this field. The meeting was held in Vienna from 11 to 15 December 1967. Refs, figs and tabs.

  15. Neutron irradiation of seeds 2

    International Nuclear Information System (INIS)

    1968-01-01

    The irradiation of seeds with the fast neutron of research reactors has been hampered by difficulties in accurately measuring dose and in obtaining repeatable and comparable results. Co-ordinated research under an international program organized by the FAO and IAEA has already resulted in significant improvements in methods of exposing seeds in research reactors and in obtaining accurate dosimetry. This has been accomplished by the development of a standard reactor facility for the neutron irradiation of seeds and standard methods for determining fast-neutron dose and the biological response after irradiation. In this program various divisions of the IAEA and the Joint FAO/IAEA Division co-operate with a number of research institutes and reactor centres throughout the world. Results of the preliminary experiments were reported in Technical Reports Series No. 76, ''Neutron Irradiation of Seeds''. This volume contains the proceedings of a meeting of co-operators in the FAO/IAEA Neutron Seed Irradiation Program and other active scientists in this field. The meeting was held in Vienna from 11 to 15 December 1967. Refs, figs and tabs

  16. Chocolate Numbers

    OpenAIRE

    Ji, Caleb; Khovanova, Tanya; Park, Robin; Song, Angela

    2015-01-01

    In this paper, we consider a game played on a rectangular $m \\times n$ gridded chocolate bar. Each move, a player breaks the bar along a grid line. Each move after that consists of taking any piece of chocolate and breaking it again along existing grid lines, until just $mn$ individual squares remain. This paper enumerates the number of ways to break an $m \\times n$ bar, which we call chocolate numbers, and introduces four new sequences related to these numbers. Using various techniques, we p...

  17. Number theory

    CERN Document Server

    Andrews, George E

    1994-01-01

    Although mathematics majors are usually conversant with number theory by the time they have completed a course in abstract algebra, other undergraduates, especially those in education and the liberal arts, often need a more basic introduction to the topic.In this book the author solves the problem of maintaining the interest of students at both levels by offering a combinatorial approach to elementary number theory. In studying number theory from such a perspective, mathematics majors are spared repetition and provided with new insights, while other students benefit from the consequent simpl

  18. Pulsed neutron sources for epithermal neutrons

    International Nuclear Information System (INIS)

    Windsor, C.G.

    1978-01-01

    It is shown how accelerator based neutron sources, giving a fast neutron pulse of short duration compared to the neutron moderation time, promise to open up a new field of epithermal neutron scattering. The three principal methods of fast neutron production: electrons, protons and fission boosters will be compared. Pulsed reactors are less suitable for epithermal neutrons and will only be briefly mentioned. The design principle of the target producing fast neutrons, the moderator and reflector to slow them down to epithermal energies, and the cell with its beam tubes and shielding will all be described with examples taken from the new Harwell electron linac to be commissioned in 1978. A general comparison of pulsed neutron performance with reactors is fraught with difficulties but has been attempted. Calculation of the new pulsed source fluxes and pulse widths is now being performed but we have taken the practical course of basing all comparisons on extrapolations from measurements on the old 1958 Harwell electron linac. Comparisons for time-of-flight and crystal monochromator experiments show reactors to be at their best at long wavelengths, at coarse resolution, and for experiments needing a specific incident wavelength. Even existing pulsed sources are shown to compete with the high flux reactors in experiments where the hot neutron flux and the time-of-flight methods can be best exploited. The sources under construction can open a new field of inelastic neutron scattering based on energy transfer up to an electron volt and beyond

  19. Occupational Mortality, Background on

    DEFF Research Database (Denmark)

    Lynge, Elsebeth

    2016-01-01

    in England and Wales from 1851 to 1979–1983, and these studies have provided key data on social inequalities in health. Death certificate studies have been used for identification of occupational groups with high excess risks from specific diseases. Follow-up studies require linkage of individual records......The study of occupational mortality involves the systematic tabulation of mortality by occupational or socioeconomic groups. Three main methods are used to conduct these studies: cross-sectional studies, death certificate studies, and follow-up studies. Cross-sectional studies were undertaken...

  20. Nice numbers

    CERN Document Server

    Barnes, John

    2016-01-01

    In this intriguing book, John Barnes takes us on a journey through aspects of numbers much as he took us on a geometrical journey in Gems of Geometry. Similarly originating from a series of lectures for adult students at Reading and Oxford University, this book touches a variety of amusing and fascinating topics regarding numbers and their uses both ancient and modern. The author intrigues and challenges his audience with both fundamental number topics such as prime numbers and cryptography, and themes of daily needs and pleasures such as counting one's assets, keeping track of time, and enjoying music. Puzzles and exercises at the end of each lecture offer additional inspiration, and numerous illustrations accompany the reader. Furthermore, a number of appendices provides in-depth insights into diverse topics such as Pascal’s triangle, the Rubik cube, Mersenne’s curious keyboards, and many others. A theme running through is the thought of what is our favourite number. Written in an engaging and witty sty...

  1. Laboratory Approaches to Studying Occupants

    DEFF Research Database (Denmark)

    Wagner, Andreas; Andersen, Rune; Zhang, Hui

    2018-01-01

    is high and a large number of physical, physiological, and psychological quantities can be monitored. This chapter gives an overview of various types of test facilities in the world and their main features in terms of experimental opportunities. It then presents typical technical equipment and sensor......Laboratories offer the possibility to study occupant behavior in a very detailed manner. A wide range of indoor environmental scenarios can be simulated under precisely controlled conditions, and human subjects can be selected based on pre-defined criteria. The degree of control over experiments...

  2. Neutron radiography at the SCK/CEN

    International Nuclear Information System (INIS)

    Tourwe, H.

    1977-01-01

    Neutron radiography has become in recent years a very important method of nondestructive testing in industry and research. The earliest practical application of neutron radiography has probably been the inspection of highly radioactive material: originally irradiated reactor fuels. Applications then progressed to other nuclear and industrial inspection problems. Neutron radiography and the conventional X-ray or gamma techniques are complementary. Some of the most important application fields of neutron radiography are: the detection of light elements (H, Li, B,...) with a very high scattering of absorption cross section for thermal neutrons; the nondestructive control of fuel before and after irradiation; controls where a distinction has to be made between isotopes of the same element ( 235 U and 238 U, 10 B and 11 B,...) and between components of a similar atomic number (Fe and Zn); the control of materials with a high density; the study of corrosion in closed structures; the control of the homogeneity of foreign materials in alloys,.... (author)

  3. Activation analysis opportunities using cold neutron beams

    Energy Technology Data Exchange (ETDEWEB)

    Lindstrom, R M; Zeisler, R; Rossbach, M

    1987-05-01

    Guided beams of cold neutrons being installed at a number of research reactors may become increasingly available for analytical research. A guided cold beam will provide higher neutron fluence rates and lower background interferences than in present facilities. In an optimized facility, fluence rates of 10/sup 9/ nxcm/sup -2/xs/sup -1/ are obtainable. Focusing a large area beam onto a small target will further increase the neutron intensity. In addition, the shift to lower neutron energy increases the effective cross sections. The absence of fast neutrons and gamma rays permits detectors to be placed near the sample without intolerable background, and thus the efficiency for counting prompt gamma rays can be much higher than in present systems. Measurements made at the hydrogen cold source of the FRJ-2 (DIDO) reactor at the KFA provide a numerical evaluation of the improvements in PGAA with respect to signal-to-background ratios of important elements and matrices. (author) 15 refs.

  4. Outer crust of nonaccreting cold neutron stars

    International Nuclear Information System (INIS)

    Ruester, Stefan B.; Hempel, Matthias; Schaffner-Bielich, Juergen

    2006-01-01

    The properties of the outer crust of nonaccreting cold neutron stars are studied by using modern nuclear data and theoretical mass tables, updating in particular the classic work of Baym, Pethick, and Sutherland. Experimental data from the atomic mass table from Audi, Wapstra, and Thibault of 2003 are used and a thorough comparison of many modern theoretical nuclear models, both relativistic and nonrelativistic, is performed for the first time. In addition, the influences of pairing and deformation are investigated. State-of-the-art theoretical nuclear mass tables are compared to check their differences concerning the neutron drip line, magic neutron numbers, the equation of state, and the sequence of neutron-rich nuclei up to the drip line in the outer crust of nonaccreting cold neutron stars

  5. Lightweight Double Neutron Star Found

    Science.gov (United States)

    Kohler, Susanna

    2018-02-01

    More than forty years after the first discovery of a double neutron star, we still havent found many others but a new survey is working to change that.The Hunt for PairsThe observed shift in the Hulse-Taylor binarys orbital period over time as it loses energy to gravitational-wave emission. [Weisberg Taylor, 2004]In 1974, Russell Hulse and Joseph Taylor discovered the first double neutron star: two compact objects locked in a close orbit about each other. Hulse and Taylors measurements of this binarys decaying orbit over subsequent years led to a Nobel prize and the first clear evidence of gravitational waves carrying energy and angular momentum away from massive binaries.Forty years later, we have since confirmed the existence of gravitational waves directly with the Laser Interferometer Gravitational-Wave Observatory (LIGO). Nonetheless, finding and studying pre-merger neutron-star binaries remains a top priority. Observing such systems before they merge reveals crucial information about late-stage stellar evolution, binary interactions, and the types of gravitational-wave signals we expect to find with current and future observatories.Since the Hulse-Taylor binary, weve found a total of 16 additional double neutron-star systems which represents only a tiny fraction of the more than 2,600 pulsars currently known. Recently, however, a large number of pulsar surveys are turning their eyes toward the sky, with a focus on finding more double neutron stars and at least one of them has had success.The pulse profile for PSR J1411+2551 at 327 MHz. [Martinez et al. 2017]A Low-Mass DoubleConducted with the 1,000-foot Arecibo radio telescope in Puerto Rico, the Arecibo 327 MHz Drift Pulsar Survey has enabled the recent discovery of dozens of pulsars and transients. Among them, as reported by Jose Martinez (Max Planck Institute for Radio Astronomy) and coauthors in a recent publication, is PSR J1411+2551: a new double neutron star with one of the lowest masses ever measured

  6. Gossip and Occupational Ideology

    Science.gov (United States)

    Rysman, Alexander R.

    1976-01-01

    Defines the transmission of gossip as an essential social process reflecting a shared group membership and discusses the ways in which gossip supports ideologies held by members of a specific occupation. (MH)

  7. Occupancy and Occupants’ Actions

    DEFF Research Database (Denmark)

    Schweiker, Marcel; Carlucci, Salvatore; Andersen, Rune

    2018-01-01

    to study, measure, and ultimately model. The categories are physiological, individual, environmental, and spatial adjustments. Third, a list of adaptive and non-adaptive triggers together with contextual factors that could influence occupant behavior is presented. Individual elements are further grouped...... into physical environmental, physiological, psychological, and social aspects. Finally, a comprehensive table of studies related to occupant behavior and the corresponding significant and non-significant predictors, based on an extensive literature review, is shown. This table highlights areas of research where......Occupants’ presence and actions within the built environment are crucial aspects related to understanding variations in energy use. Within this chapter, first, a nomenclature for the field of research dealing with occupants in buildings is defined. This nomenclature distinguishes between occupants...

  8. Occupational lung diseases.

    Science.gov (United States)

    Furlow, Bryant

    2011-01-01

    Chest radiography and high-resolution computed tomography are indispensable tools in the detection, classification and characterization of occupational lung diseases that are caused by inhaling mineral particles such as asbestos, silicon-containing rock dust and other tissue-damaging antigens, nanomaterials and toxins. Radiographic evidence of occupational lung disease is interpreted with a patient's clinical signs and symptoms and a detailed occupational history in mind because of high variability in radiographic findings. This Directed Reading reviews the history, epidemiology, functional anatomy, pathobiology and medical diagnostic imaging of occupational lung diseases associated with inhalation of fine particulates in the workplace. This article is a Directed Reading. Your access to Directed Reading quizzes for continuing education credit is determined by your CE preference. For access to other quizzes, go to www.asrt.org/store.

  9. Occupants' window opening behaviour

    DEFF Research Database (Denmark)

    Fabi, Valentina; Andersen, Rune Korsholm; Corgnati, Stefano

    2012-01-01

    Energy consumption in buildings is influenced by several factors related to the building properties and the building controls, some of them highly connected to the behaviour of their occupants.In this paper, a definition of items referring to occupant behaviour related to the building control...... systems is proposed, based on studies presented in literature and a general process leading to the effects on energy consumptions is identified.Existing studies on the topic of window opening behaviour are highlighted and a theoretical framework to deal with occupants' interactions with building controls......, aimed at improving or maintaining the preferred indoor environmental conditions, is elaborated. This approach is used to look into the drivers for the actions taken by the occupants (windows opening and closing) and to investigate the existing models in literature of these actions for both residential...

  10. Neutronics in ICF reactor ''SENRI-I''

    International Nuclear Information System (INIS)

    Nakai, S.; Ido, S.; Yamanaka, C.

    1983-01-01

    The neutronic behavior of SENRI-I has been examined taking into account the effect of fuel rhoR and Pb tamper on the emitted neutron from micro-explosion. One dimensional neutron transport was calculated by ANISIN-JR code with the nuclear data GICX-40. The effect of beam ports on neutronics and neutron streaming was examined by the three dimensional Monte-Carlo calculation code MORSE-E with the same nuclear data. The emitted neutrons are softened noticeably by the increase of the compressed fuel rhoR and the thickness of Pb coating. The latter also multiplies the net neutron number from pellet. The energy deposition and temperature increase and its distribution in the blankets and structural elements were obtained as a function of neutron spectrum from pellet. As for the tritium breeding ratio, the softening of neutron has little effect because the decrease of breeding by 7 Li with softening is compensated by the increase of breeding by 6 Li. The breeding ratio was 1.678, 1.639 and 1.576 with 14 MeV neutron, rhoR=0.7, rhoR=3 and rhoR=6 respectively. Neutron shielding and streaming from beam ports were examined and the dose rate of final optical elements were calculated to estimate the life of mirror. All these results show the feasibility of SENRI-I as a long life, maintenance free ICF pulse reactor and motivate to go further investigation and design studies in detail. (author)

  11. Progress towards magnetic trapping of ultra-cold neutrons

    CERN Document Server

    Huffman, P R; Butterworth, J S; Coakley, K J; Dewey, M S; Dzhosyuk, S N; Gilliam, D M; Golub, R; Greene, G L; Habicht, K; Lamoreaux, S K; Mattoni, C E H; McKinsey, D N; Wietfeldt, F E; Doyle, J M

    2000-01-01

    We report progress towards magnetic trapping of ultra-cold neutrons (UCN) in preparation for a neutron lifetime measurement. UCN will be produced by inelastic scattering of cold (0.89 nm) neutrons in a reservoir of superfluid sup 4 He and confined in a three-dimensional magnetic trap. As the trapped neutrons decay, recoil electrons will generate scintillations in the liquid He, which should be detectable with nearly 100% efficiency. This direct measure of the number of UCN decays vs. time can be used to determine the neutron beta-decay lifetime.

  12. Occupational choice and values.

    OpenAIRE

    Kantas, A.

    1985-01-01

    It is suggested that psychological and sociological approaches to occupational choice can be linked together by employment of three concepts: work salience, values and motivation. Employing Vroom's (1964) cognitive model of motivation occupational choice was examined as a value attainment process. The subjects were 225 male pupils of two different school complexes in Athens, Greece. They were asked to respond to a work salience questionnaire and to rank order a set of ...

  13. Occupational health in Mexico.

    Science.gov (United States)

    Carreón, Tania; Santos-Burgoa, Carlos; Baron, Sherry; Hernández, Sendy

    2002-01-01

    The authors discuss the maquiladoras and child labor, and offer an overview of the history of occupational safety and health in Mexico that covers laws and regulations, social security, unions, and enforcement of legislation. The organization and structure of the various institutions responsible for occupational safety and health (OSH), as well as administrative procedures, are described. This article concludes with a list of the new challenges for OSH in Mexico.

  14. Radiation protection: occupational exposure

    International Nuclear Information System (INIS)

    Shah, G.A.

    1990-01-01

    The basis of the occupational exposure limit of 50 mSv recommended by the ICRP is questioned. New dosimetry at Hiroshima and Nagasaki, the fact that the dose-response curve may be non-linear and that the relative risk model may be applicable, are some of the arguments advanced to support a reduction in the occupational exposure dose limits. 5 refs., 2 tabs., 3 figs

  15. Occupational exposures. Annex H

    International Nuclear Information System (INIS)

    1982-01-01

    This Annex focuses on significant changes in the pattern of occupational exposure which have appeared since the 1972 and 1962 reports, and presents information on trends or particular causes of high exposures. A further objective is to clarify the reasons for which the Committee requires data on occupational exposure, and to suggest areas in which better data collection or analysis may be performed. Data are also reviewed on accidents involving the exposure of workers to substantial radiation doses.

  16. Occupational health in Malaysia.

    Science.gov (United States)

    Rampal, Krishna Gopal; Aw, Tar-Ching; Jefferelli, Shamsul Bahrin

    2002-01-01

    This article provides a detailed examination of Malaysian occupational health agencies and their roles in formulating and enforcing standards, promoting occupational health and safety (OSH), and providing advisory services. Available OSH training is described, and the need for policies and personnel in various industries is outlined. Further, the authors discuss how international models and collaboration have influenced Malaysian OSH, and how some successes can be repeated and failures remedied.

  17. Tuberculosis as occupational disease

    OpenAIRE

    Mendoza-Ticona, Alberto; Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia. Lima, Perú. Médico infectólogo tropicalista magister en Epidemiología Clínica.

    2014-01-01

    There is enough evidence to declare tuberculosis as an occupational disease among healthcare workers. In Peru, there are regulations granting employment rights regarding tuberculosis as an occupational disease, such as healthcare coverage for temporary or permanent disability. However, these rights have not been sufficiently socialized. This study presents information on the risk of acquiring tuberculosis in the workplace, and a review of the evidence to declare tuberculosis as an occupationa...

  18. Development of self-powered neutron detectors for neutron flux monitoring in HCLL and HCPB ITER-TBM

    International Nuclear Information System (INIS)

    Angelone, M.; Klix, A.; Pillon, M.; Batistoni, P.; Fischer, U.; Santagata, A.

    2014-01-01

    Highlights: •Self powered neutron detector (SPND) is attractive neutron monitor for TBM in ITER. •In hard neutron spectra (e.g. TBM) there is the need to optimize their response. •Three state-of-the-art SPNDs were tested using fast and 14 MeV neutrons. •The response of SPNDs is much lower than in thermal neutron flux. •FISPACT calculations performed to find out candidate materials in hard spectra. -- Abstract: Self powered neutron detectors (SPND) have a number of interesting properties (e.g. small dimensions, capability to operate in harsh environments, absence of external bias), so they are attractive neutron monitors for TBM in ITER. However, commercially available SPNDs are optimized for operation in a thermal nuclear reactor where the neutron spectrum is much softer than that expected in a TBM. This fact can limit the use of SPND in a TBM since the effective cross sections for the production of beta emitters are much lower in a fast neutron spectrum. This work represents the first attempt to study SPNDs as neutron flux monitors for TBM. Three state-of-the-art SPND available on the market were bought and tested using fast neutrons at TAPIRO fast neutron source of ENEA Casaccia and with 14 MeV neutrons at the Frascati neutron generator (FNG). The results clearly indicate that in fast neutron spectra, the response of SPNDs is much lower than in thermal neutron flux. Activation calculations were performed using the FISPACT code to find out possible material candidates for SPND suitable for operation in TBM neutron spectra

  19. Development of self-powered neutron detectors for neutron flux monitoring in HCLL and HCPB ITER-TBM

    Energy Technology Data Exchange (ETDEWEB)

    Angelone, M., E-mail: maurizio.angelone@enea.it [Associazione ENEA-EURATOM sulla FusioneENEA C.R. Frascati, Via E. Fermi 45, 00044 Frascati (Italy); Klix, A. [Association KIT-EURATOM, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Pillon, M.; Batistoni, P. [Associazione ENEA-EURATOM sulla FusioneENEA C.R. Frascati, Via E. Fermi 45, 00044 Frascati (Italy); Fischer, U. [Association KIT-EURATOM, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Santagata, A. [ENEA C.R. Casaccia, via Anguillarese Km. 1,300, 00100 Roma (Italy)

    2014-10-15

    Highlights: •Self powered neutron detector (SPND) is attractive neutron monitor for TBM in ITER. •In hard neutron spectra (e.g. TBM) there is the need to optimize their response. •Three state-of-the-art SPNDs were tested using fast and 14 MeV neutrons. •The response of SPNDs is much lower than in thermal neutron flux. •FISPACT calculations performed to find out candidate materials in hard spectra. -- Abstract: Self powered neutron detectors (SPND) have a number of interesting properties (e.g. small dimensions, capability to operate in harsh environments, absence of external bias), so they are attractive neutron monitors for TBM in ITER. However, commercially available SPNDs are optimized for operation in a thermal nuclear reactor where the neutron spectrum is much softer than that expected in a TBM. This fact can limit the use of SPND in a TBM since the effective cross sections for the production of beta emitters are much lower in a fast neutron spectrum. This work represents the first attempt to study SPNDs as neutron flux monitors for TBM. Three state-of-the-art SPND available on the market were bought and tested using fast neutrons at TAPIRO fast neutron source of ENEA Casaccia and with 14 MeV neutrons at the Frascati neutron generator (FNG). The results clearly indicate that in fast neutron spectra, the response of SPNDs is much lower than in thermal neutron flux. Activation calculations were performed using the FISPACT code to find out possible material candidates for SPND suitable for operation in TBM neutron spectra.

  20. A guide to spirometry as applied to occupational health | White ...

    African Journals Online (AJOL)

    In the context of occupational health, spirometric testing of respiratory function has a number of important applications. These applications can be expected to become more widespread in view of extensive changes to occupational health and compensation legislation in South Africa. Spirometry is an essential component of ...

  1. A search strategy for occupational health intervention studies

    NARCIS (Netherlands)

    Verbeek, J.; Salmi, J.; Pasternack, I.; Jauhiainen, M.; Laamanen, I.; Schaafsma, F.; Hulshof, C.; van Dijk, F.

    2005-01-01

    As a result of low numbers and diversity in study type, occupational health intervention studies are not easy to locate in electronic literature databases. To develop a search strategy that facilitates finding occupational health intervention studies in Medline, both for researchers and

  2. Evidence Based Prevention of Occupational Slips, Trips and Falls

    DEFF Research Database (Denmark)

    Jensen, Olaf Chresten

    2009-01-01

    It is estimated that about one third of the compensated occupational injuries and half of the most serious occupational injuries in merchant seafaring are related to slips, trips and falls (STF)-events. Among the elderly, STF is the risk factor that causes the largest number of inpatient days...

  3. Number names and number understanding

    DEFF Research Database (Denmark)

    Ejersbo, Lisser Rye; Misfeldt, Morten

    2014-01-01

    This paper concerns the results from the first year of a three-year research project involving the relationship between Danish number names and their corresponding digits in the canonical base 10 system. The project aims to develop a system to help the students’ understanding of the base 10 syste...... the Danish number names are more complicated than in other languages. Keywords: A research project in grade 0 and 1th in a Danish school, Base-10 system, two-digit number names, semiotic, cognitive perspectives....

  4. Layered semiconductor neutron detectors

    Science.gov (United States)

    Mao, Samuel S; Perry, Dale L

    2013-12-10

    Room temperature operating solid state hand held neutron detectors integrate one or more relatively thin layers of a high neutron interaction cross-section element or materials with semiconductor detectors. The high neutron interaction cross-section element (e.g., Gd, B or Li) or materials comprising at least one high neutron interaction cross-section element can be in the form of unstructured layers or micro- or nano-structured arrays. Such architecture provides high efficiency neutron detector devices by capturing substantially more carriers produced from high energy .alpha.-particles or .gamma.-photons generated by neutron interaction.

  5. A neutron activation detector

    International Nuclear Information System (INIS)

    Ambardanishvili, T.S.; Kolomiitsev, M.A.; Zakharina, T.Y.; Dundua, V.J.; Chikhladze, N.V.

    1973-01-01

    The present invention concerns a neutron activation detector made from a moulded and hardened composition. According to the invention, that composition contains an activable substance constituted by at least two chemical elements and/or compounds of at least two chemical elements. Each of these chemical elements is capable of reacting with the neutrons forming radio-active isotopes with vatious levels of energy during desintegration. This neutron detector is mainly suitable for measuring integral thermal neutron and fast neutron fluxes during irradiation of the sample, and also for measuring the intensities of neutron fields [fr

  6. Very slow neutrons

    International Nuclear Information System (INIS)

    Frank, A.

    1983-01-01

    The history is briefly presented of the research so far of very slow neutrons and their basic properties are explained. The methods are described of obtaining very slow neutrons and the problems of their preservation are discussed. The existence of very slow neutrons makes it possible to perform experiments which may deepen the knowledge of the fundamental properties of neutrons. Their wavelength approximates that of visible radiation. The possibilities and use are discussed of neutron optical systems (neutron microscope) which could be an effective instrument for the study of the detailed arrangement, especially of organic substances. (B.S.)

  7. Reactor neutron dosimetry

    International Nuclear Information System (INIS)

    Najzer, M.; Pauko, M.; Glumac, B.; Acquah, I.N.; Moskon, F.

    1977-01-01

    An analysis of requirements and possibilities for experimental neutron spectrum determination during the reactor pressure vessel surveil lance programme is given. Fast neutron spectrum and neutron dose rate were measured in the Fast neutron irradiation facility of our TRIGA reactor. It was shown that the facility can be used for calibration of neutron dosimeters and for irradiation of samples sensitive to neutron radiation. The investigation of the unfolding algorithm ITER was continued. Based on this investigations are two specialized unfolding program packages ITERAD and ITERGS written this year. They are able to unfold data from activation detectors and NaI(T1) gamma spectrometer respectively

  8. Occupational stressors in nursing

    Directory of Open Access Journals (Sweden)

    N. Nikpeyma

    2009-04-01

    Full Text Available Background and aimsNursing provides a wide range of potential workplace stressors as it is  a profession that requires a high level of skill, teamworking in a variety of situations and provision  of 24-hour delivery of care .Occupational stress is a major factor of Staff sickness an  absenteeism.This study investigates the main occupational stressors in nursing profession in the  hope of identification and reducing it.MethodsIn this study a questionnaire consisting of three parts:demoghraphic data,the nurses  background and questions about occupational stress from Revised index fulfilled by 140 nurses.ResultsLack of reward for work well done(48/6%, Heavy workload(46/4% ,lack of Participation in decisions (39/3% , poor Control of work place(38/4%and lack of job  development (36/4% have been the main sources of Occupational stress for nurses.chronic  diseases, Night Shift working and working hours were positively associated with occupstional  stress.Conclusion Analysis indicated that effects of work factors on occupational stress are more than demoghraphic data. The findings of this study can assist health service organisations to provide an attractive working climate in order to decrease side effects and consequences of occupational stress. Furthermore, understanding this situation can help to develop coping strategies in order to reduce work-related stress.

  9. Viral hepatitis as an occupational disease in Poland.

    Science.gov (United States)

    Bilski, Bartosz

    2011-07-01

    In medical terms, occupational diseases are defined as health disorders specifically associated with the working environment of people and their occupational activity. From the medical and legal perspectives, the vast majority of European countries consider particular diseases to be of occupational origin if they are mentioned in the current list of occupational diseases and caused by exposure to factors in the working environment that are harmful to health. The aim of this study was to analyze the occurrence of cases of viral hepatitis certified as an occupational disease in Poland during 1979-2009. This article presents the medical, economic, and legal aspects of the epidemiology of hepatitis as an occupational disease in Poland. Publically available statistical data on certified occupational diseases in Poland and data contained in individual "occupational disease diagnosis cards" (based on data used in Poland statistical form), regarding certified cases of hepatitis among health care professionals, which were collected by the Department of Occupational Hygiene of the Polish Public Health Service, were analyzed in this study. In Poland, the highest number of cases of hepatitis certified as an occupational disease was observed in 1987. A gradual reduction in the number of cases of hepatitis as an occupational disease has been noted since then. Currently, hepatitis C as an occupational disease is certified more frequently than hepatitis B. In Poland, the number of women with hepatitis certified as an occupational disease is higher than that of men. However, among health care professionals, particularly nurses, this difference is insignificant because women outnumber the men. The existence of such a situation is due to the significant quantitative predominance of women over men among medical personnel, especially among nurses. Immunization of health care professionals against the hepatitis B virus (HBV), introduced in Poland in 1988, was an important factor

  10. A 'hybrid' neutron area survey instrument for the determination of neutron dose quantities in the workplace

    International Nuclear Information System (INIS)

    Tanner, R.J.; Jenkins, R.; Lowe, T.; Silvie, J.; Joyce, M.J.; Winsby, A.; Molinos, C.

    2005-01-01

    Full text: Neutron survey instruments are used routinely to determine the dose rates in areas where persons may be occupationally exposed. With a few exceptions, these instruments generally use a proportional counter with a high thermal neutron response located in a moderating sphere of CH 2 . The moderating sphere in such designs contains a thermal neutron absorber to reduce the over-response to thermal and intermediate energy neutrons. However, the commercially available examples of such instruments tend to have strongly energy dependent ambient dose equivalent response characteristics. In particular, they often over-respond in the energy range between 1 eV and 10 keV. A prototype of a novel design has been produced that uses seven detectors located in a moderating sphere of CH 2 , six near the surface to detect thermal and epithermal neutrons, and one in the centre to detect fast neutrons. This has been characterized using a combination of MCNP modelling and measurements to produce an instrument that has improved energy dependence of response characteristics. Additionally, the use of seven detectors offers direction and field hardness information. The design and calibration of the instrument are described and its response in workplaces calculated. (author)

  11. Neutron stochastic transport theory with delayed neutrons

    International Nuclear Information System (INIS)

    Munoz-Cobo, J.L.; Verdu, G.

    1987-01-01

    From the stochastic transport theory with delayed neutrons, the Boltzmann transport equation with delayed neutrons for the average flux emerges in a natural way without recourse to any approximation. From this theory a general expression is obtained for the Feynman Y-function when delayed neutrons are included. The single mode approximation for the particular case of a subcritical assembly is developed, and it is shown that Y-function reduces to the familiar expression quoted in many books, when delayed neutrons are not considered, and spatial and source effects are not included. (author)

  12. Funny Numbers

    Directory of Open Access Journals (Sweden)

    Theodore M. Porter

    2012-12-01

    Full Text Available The struggle over cure rate measures in nineteenth-century asylums provides an exemplary instance of how, when used for official assessments of institutions, these numbers become sites of contestation. The evasion of goals and corruption of measures tends to make these numbers “funny” in the sense of becoming dis-honest, while the mismatch between boring, technical appearances and cunning backstage manipulations supplies dark humor. The dangers are evident in recent efforts to decentralize the functions of governments and corporations using incen-tives based on quantified targets.

  13. Transcendental numbers

    CERN Document Server

    Murty, M Ram

    2014-01-01

    This book provides an introduction to the topic of transcendental numbers for upper-level undergraduate and graduate students. The text is constructed to support a full course on the subject, including descriptions of both relevant theorems and their applications. While the first part of the book focuses on introducing key concepts, the second part presents more complex material, including applications of Baker’s theorem, Schanuel’s conjecture, and Schneider’s theorem. These later chapters may be of interest to researchers interested in examining the relationship between transcendence and L-functions. Readers of this text should possess basic knowledge of complex analysis and elementary algebraic number theory.

  14. Neutron scattering equipments in JAERI. Current status

    International Nuclear Information System (INIS)

    Hamaguchi, Yoshikazu; Minakawa, Nobuaki

    2003-01-01

    24 neutron scattering instruments are installed in the JRR-3M research reactor. Among them JAERI has 12 neutron scattering instruments. Those instruments are HRPD for high-resolution structural analysis, TAS-1 and TAS-2 for elastic and inelastic scattering and for magnetic scattering measurements by the polarized neutron, LTAS for elastic and inelastic scattering measurement at a low energy region, and for neutron device development, PNO for topography and for very small angle scattering measurement in a small Q range, NRG for neutron radiography, RESA for internal strain measurements, SANS for the molecule and semi-macroscopic magnetic structural analysis, BIX-2 and BIX-3 for the biological structural analysis research, and PGA for the research of prompt gamma-ray analysis. The university groups have 12 neutron scattering instruments. Since those instruments were installed at the period when JRR-3M was completed, about 10 years have passed. In order to match the old control systems with the progress of recent computer technologies, and peripheral equipment, numbers of instruments are being renewed. In the neutron guide hall of JRR-3M, the Ni mirror guide tube was replaced by a super mirror guide tube to increase neutron flux. The intensity of 2A flux was increased by a factor of about two. (J.P.N.)

  15. Neutrons and carcinogenesis: a cautionary tale

    International Nuclear Information System (INIS)

    Hall, E.J.

    1996-01-01

    The best estimates for radiation induced cancer and leukemia are based on the Japanese survivors of Hiroshima and Nagasaki. With the earlier dosimetry systems of the 1960's, it was possible to derive an RBE (relative biological effectiveness) for neutrons from the Japanese data, because it was thought that there was a significant neutron dose at Hiroshima compared with Nagasaki. The estimated RBE of about 20 was consistent with laboratory estimates for oncogenic transformation in vitro and tumors in animals. The revised dosimetry of the 1980's [DS 86] essentially eliminated the neutron component at Hiroshima, and consequently removed the only neutron RBE estimate based on human data. However, recent neutron activation measurements indicate that these may indeed have been thermal neutrons at Hiroshima, and measurements of the ratio of inter- to intra-chromosomal aberrations in peripheral lymphocytes of survivors also tend to indicate that the biologically effective dose was dominated by neutrons. Another area in which the large biological effectiveness of neutrons assumes importance is the production of photoneutrons in high energy medical linear accelerators (Linacs). An increasing number of accelerators operating in the 18 to 20 MV range are coming into routine clinical use and at this energy, photoneutrons generated largely in the collimators result in a total body dose to the patient. The increased risk of second malignancies must be balanced against the slight improvement in percentage depth doses compared with more conventional machines operating at to 10 MV, below the threshold for photoneutron production. (author)

  16. A gamma-ray discriminating neutron scintillator

    International Nuclear Information System (INIS)

    Eschbach, P.A.; Miller, S.D.; Cole, M.C.

    1994-01-01

    A neutron scintillator has been developed at Pacific Northwest Laboratory which responds directly to as little as 10 mrem/hour dose equivalent rate fast neutron fields. The scintillator is composed of CaF 2 :Eu or of NaI grains within a silicone rubber or polystyrene matrix, respectively. Neutrons colliding with the plastic matrix provide knockon protons, which in turn deposit energy within the grains of phosphor to produce pulses of light. Neutron interactions are discriminated from gamma-ray events on the basis of pulse height. Unlike NE-213 liquid scintillators, this solid scintillator requires no pulseshape discrimination and therefore requires less hardware. Neutron events are anywhere from two to three times larger than the gamma-ray exposures are compared to 0.7 MeV gamma-ray exposures. The CaF 2 :Eu/silicone rubber scintillator is nearly optically transparent, and can be made into a very sizable detector (4 cm x 1.5 cm) without degrading pulse height. This CaF 2 :Eu scintillator has been observed to have an absolute efficiency of 0.1% when exposed to 5-MeV accelerator-generated neutrons (where the absolute efficiency is the ratio of observed neutron events divided by the number of fast neutrons striking the detector)

  17. Urinary metallothionein as a biological indicator of occupational cadmium exposure

    International Nuclear Information System (INIS)

    Tohyama, C.; Shaikh, Z.A.; Ellis, K.J.; Cohn, S.H.

    1981-01-01

    Radioimmunoassay and neutron activation data indicate that the urinary metallothionein concentration is related to the liver Cd concentration in occupational Cd exposure. It is also related to the kidney Cd content - but only before the onset of renal dysfunction. Further epidemiological studies are needed to establish a dose-response relationship, which may be useful in minimizing the hazard of Cd-induced renal dysfunction

  18. Population Health and Occupational Therapy.

    Science.gov (United States)

    Braveman, Brent

    2016-01-01

    Occupational therapy practitioners play an important role in improving the health of populations through the development of occupational therapy interventions at the population level and through advocacy to address occupational participation and the multiple determinants of health. This article defines and explores population health as a concept and describes the appropriateness of occupational therapy practice in population health. Support of population health practice as evidenced in the official documents of the American Occupational Therapy Association and the relevance of population health for occupational therapy as a profession are reviewed. Recommendations and directions for the future are included related to celebration of the achievements of occupational therapy practitioners in the area of population health, changes to the Occupational Therapy Practice Framework and educational accreditation standards, and the importance of supporting, recognizing, rewarding, and valuing occupational therapy practitioners who assume roles in which direct care is not their primary function. Copyright © 2016 by the American Occupational Therapy Association, Inc.

  19. Occupational Experience, Mobility, and Wages

    DEFF Research Database (Denmark)

    Groes, Fane

    In this paper we present how occupational tenure relates to wage growth and occupational mobility in Danish data. We show that the Danish data produces qualitatively similar results as found in U.S. data with respect to an increase in average wages when experience in an occupation increases. In a...... also is true for workers switching occupation and rm. After ve years of experience in an occupation the average probability of switching any type of occupation, including occupation and rm switches, has fallen from 25% to 12%........ In a sample of full time private employed, the first five years of experience in an occupation increases average wages with 8% to 15%, conditional on rm and industry tenure. We further show that the probability of switching occupation declines with experience in the occupation and that the declining hazard...

  20. Occupation and occupational exposure to endocrine disrupting chemicals in male breast cancer: a case-control study in Europe

    DEFF Research Database (Denmark)

    Villeneuve, Sara; Cyr, Diane; Lynge, Elsebeth

    2010-01-01

    Male breast cancer is a rare disease of largely unknown aetiology. In addition to genetic and hormone-related risk factors, a large number of environmental chemicals are suspected of playing a role in breast cancer. The identification of occupations or occupational exposures associated with an in...

  1. Transfinite Numbers

    Indian Academy of Sciences (India)

    this is a characteristic difference between finite and infinite sets and created an immensely useful branch of mathematics based on this idea which had a great impact on the whole of mathe- matics. For example, the question of what is a number (finite or infinite) is almost a philosophical one. However Cantor's work turned it ...

  2. Neutron anatomy

    Energy Technology Data Exchange (ETDEWEB)

    Bacon, G.E. [Univ. of Sheffield (United Kingdom)

    1994-12-31

    The familiar extremes of crystalline material are single-crystals and random powders. In between these two extremes are polycrystalline aggregates, not randomly arranged but possessing some preferred orientation and this is the form taken by constructional materials, be they steel girders or the bones of a human or animal skeleton. The details of the preferred orientation determine the ability of the material to withstand stress in any direction. In the case of bone the crucial factor is the orientation of the c-axes of the mineral content - the crystals of the hexagonal hydroxyapatite - and this can readily be determined by neutron diffraction. In particular it can be measured over the volume of a piece of bone, utilizing distances ranging from 1mm to 10mm. The major practical problem is to avoid the intense incoherent scattering from the hydrogen in the accompanying collagen; this can best be achieved by heat-treatment and it is demonstrated that this does not affect the underlying apatite. These studies of bone give leading anatomical information on the life and activities of humans and animals - including, for example, the life history of the human femur, the locomotion of sheep, the fracture of the legs of racehorses and the life-styles of Neolithic tribes. We conclude that the material is placed economically in the bone to withstand the expected stresses of life and the environment. The experimental results are presented in terms of the magnitude of the 0002 apatite reflection. It so happens that for a random powder the 0002, 1121 reflections, which are neighboring lines in the powder pattern, are approximately equal in intensity. The latter reflection, being of manifold multiplicity, is scarcely affected by preferred orientation so that the numerical value of the 0002/1121 ratio serves quite accurately as a quantitative measure of the degree of orientation of the c-axes in any chosen direction for a sample of bone.

  3. Neutron anatomy

    International Nuclear Information System (INIS)

    Bacon, G.E.

    1994-01-01

    The familiar extremes of crystalline material are single-crystals and random powders. In between these two extremes are polycrystalline aggregates, not randomly arranged but possessing some preferred orientation and this is the form taken by constructional materials, be they steel girders or the bones of a human or animal skeleton. The details of the preferred orientation determine the ability of the material to withstand stress in any direction. In the case of bone the crucial factor is the orientation of the c-axes of the mineral content - the crystals of the hexagonal hydroxyapatite - and this can readily be determined by neutron diffraction. In particular it can be measured over the volume of a piece of bone, utilizing distances ranging from 1mm to 10mm. The major practical problem is to avoid the intense incoherent scattering from the hydrogen in the accompanying collagen; this can best be achieved by heat-treatment and it is demonstrated that this does not affect the underlying apatite. These studies of bone give leading anatomical information on the life and activities of humans and animals - including, for example, the life history of the human femur, the locomotion of sheep, the fracture of the legs of racehorses and the life-styles of Neolithic tribes. We conclude that the material is placed economically in the bone to withstand the expected stresses of life and the environment. The experimental results are presented in terms of the magnitude of the 0002 apatite reflection. It so happens that for a random powder the 0002, 1121 reflections, which are neighboring lines in the powder pattern, are approximately equal in intensity. The latter reflection, being of manifold multiplicity, is scarcely affected by preferred orientation so that the numerical value of the 0002/1121 ratio serves quite accurately as a quantitative measure of the degree of orientation of the c-axes in any chosen direction for a sample of bone

  4. Basics of Neutrons for First Responders

    Energy Technology Data Exchange (ETDEWEB)

    Rees, Brian G. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2018-02-05

    These are slides from a presentation on the basics of neutrons. A few topics covered are: common origins of terrestrial neutron radiation, neutron sources, neutron energy, interactions, detecting neutrons, gammas from neutron interactions, neutron signatures in gamma-ray spectra, neutrons and NaI, neutron fluence to dose (msV), instruments' response to neutrons.

  5. Analysis of records of external occupational dose records in Brazil; Analise dos registros de dose ocupacional externa no Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Mauricio, Claudia L.P.; Silva, Herica L.R. da, E-mail: claudia@ird.gov.br, E-mail: herica@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ),Rio de Janeiro, RJ (Brazil); Silva, Claudio Ribeiro da, E-mail: claudio@cnen.gov.br [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

    2014-07-01

    Brazil, a continental country, with actually more than 150,000 workers under individual monitoring for ionizing radiation, has implemented in 1987 a centralized system for storage of external occupational dose. This database has been improved over the years and is now a web-based information system called Brazilian External Occupational Dose Management Database System - GDOSE. This paper presents an overview of the Brazilian external occupational dose over the years. The estimated annual average effective dose shows a decrease from 2.4 mSv in 1987 to about 0.6 mSv, having been a marked reduction from 1987 to 1990. Analyzing by type of controlled practice, one sees that the medical and dental radiology is the area with the largest number of users of individual monitors (70%); followed by education practices (8%) and the industrial radiography (7%). Additionally to photon whole body monitoring; neutron monitors are used in maintenance (36%), reactor (30%) and education (27%); and extremity monitors, in education (27%), nuclear medicine (22%) and radiology (19%). In terms of collective dose, the highest values are also found in conventional radiology, but the highest average dose values are those of interventional radiology. Nuclear medicine, R and D and radiotherapy also have average annual effective dose higher than 1 mSv. However, there is some very high dose values registered in GDOSE that give false information. This should be better analyzed in the future. Annual doses above 500 are certainly not realistic. (author)

  6. Photo-Interviewing to Explore Everyday Occupation

    DEFF Research Database (Denmark)

    Bukhave, Elise Bromann; Huniche, Lotte

    2016-01-01

    Abstract This article sheds light on the potential and the limitations of photo-interviewing for the study of human occupation and in so doing, reflects the rapid growth in the use of participatory visual methods in a number of other disciplines. Using a study that explored first person perspecti...

  7. Epidemiology, occupational hygiene and health physics

    International Nuclear Information System (INIS)

    Bonnell, J.A.

    1980-01-01

    The contribution of radiation protection practices to the practice of occupational medicine and hygiene is discussed. For example, accurate studies of a number of biological systems were stimulated. It is suggested that an accurate epidemiological assessment of workers exposed at or below the recommended radiation dose limits be undertaken. (H.K.)

  8. Medical Laboratory Assistant. Laboratory Occupations Cluster.

    Science.gov (United States)

    Michigan State Univ., East Lansing. Coll. of Agriculture and Natural Resources Education Inst.

    This task-based curriculum guide for medical laboratory assistant is intended to help the teacher develop a classroom management system where students learn by doing. Introductory materials include a Dictionary of Occupational Titles job code and title sheet, a career ladder, a matrix relating duty/task numbers to job titles, and a task list. Each…

  9. Neutron radiography using neutron imaging plate

    International Nuclear Information System (INIS)

    Chankow, Nares; Wonglee, Sarinrat

    2008-01-01

    Full text: The aims of this research are to study properties of neutron imaging plate, to obtain a suitable condition for neutron radiography and to use the neutron imaging plate for testing of materials nondestructively. The experiments were carried out by using a neutron beam from the Thai Research Reactor TRR-1/M1 at a power of 1.2 MW. A BAS-ND 2040 FUJI neutron imaging plate and a MX125 Kodak X-ray film/Gadolinium neutron converter screen combination were tested for comparison. It was found that the photostimulated light (PSL) read out of the imaging plate was directly proportional to the exposure time. It was also found that radiography with neutron using the imaging plate was approximately 40 times faster than the conventional neutron radiography using x-ray film/Gd converter screen combination. The sensitivity of the imaging plate to gamma-rays was investigated by using gamma-rays from an 192 Ir and a 60 Co radiographic sources. The imaging plate was found to be 5-6 times less sensitive to gamma-rays than a FUJI BAS-MS 2040 gamma-ray imaging plate. Finally, some specimens were selected to be radiographed with neutrons using the imaging plate and the x-ray film/Gd converter screen combination in comparison to x-rays. Parts containing light elements could be clearly observed by the two neutron radiographic techniques. It could be concluded that the image quality from the neutron imaging plate was comparable to the conventional x-ray film/Gd converter screen combination but the exposure time could be approximately reduced by a factor of 40

  10. NEUTRON SPECTRUM MEASUREMENTS USING MULTIPLE THRESHOLD DETECTORS

    Energy Technology Data Exchange (ETDEWEB)

    Gerken, William W.; Duffey, Dick

    1963-11-15

    From American Nuclear Society Meeting, New York, Nov. 1963. The use of threshold detectors, which simultaneously undergo reactions with thermal neutrons and two or more fast neutron threshold reactions, was applied to measurements of the neutron spectrum in a reactor. A number of different materials were irradiated to determine the most practical ones for use as multiple threshold detectors. These results, as well as counting techniques and corrections, are presented. Some materials used include aluminum, alloys of Al -Ni, aluminum-- nickel oxides, and magesium orthophosphates. (auth)

  11. Quasi-energy of ultracold neutrons

    International Nuclear Information System (INIS)

    Frank, A.I.; Nosov, V.G.

    1992-01-01

    A solution is found to the problem of the propagation of a neutron beam transmitted through a periodically acting high-speed chopper. It is a generalization of the Moshinsky's problem of the evolution of a plane wave in the right half-space after an ideal absorber at the origin of coordinates has been instantaneously removed. The energy spectrum of transmitted neutrons is found to be discrete and corresponding to their quasi-energy. Interference of the states corresponding to different satellite lines leads to a complex spatial pattern with typical beats. A number of experiments with ultracold neutrons are suggested and discussed. 12 refs.; 1 fig

  12. Neutrons and model membranes

    Science.gov (United States)

    Fragneto, G.

    2012-11-01

    Current research in membrane protein biophysics highlights the emerging role of lipids in shaping membrane protein function. Cells and organisms have developed sophisticated mechanisms for controlling the lipid composition and many diseases are related to the failure of these mechanisms. One of the recent advances in the field is the discovery of the existence of coexisting micro-domains within a single membrane, important for regulating some signaling pathways. Many important properties of these domains remain poorly characterized. The characterization and analysis of bio-interfaces represent a challenge. Performing measurements on these few nanometer thick, soft, visco-elastic and dynamic systems is close to the limits of the available tools and methods. Neutron scattering techniques including small angle scattering, diffraction, reflectometry as well as inelastic methods are rapidly developing for these studies and are attracting an increasing number of biologists and biophysicists at large facilities. This manuscript will review some recent progress in the field and provide perspectives for future developments. It aims at highlighting neutron reflectometry as a versatile method to tackle questions dealing with the understanding and function of biomembranes and their components. The other important scattering methods are only briefly introduced.

  13. The 1986 residential occupant survey

    Energy Technology Data Exchange (ETDEWEB)

    Ivey, D.L.; Alley, P.K.

    1987-04-01

    In 1986, Pacific Northwest Laboratory developed the Residential Occupant Survey-Spring '86, which was implemented. The overall purpose of the study was to collect demographic, attitudinal, and behavioral data related to the use and conservation of electricity in dwellings participating in the Bonneville Power Administration's End-Use Load and Conservation Assessment Program (ELCAP). Information was collected on the respondents' perceptions of the energy efficiency of their dwelling, temperature the dwelling was kept when people were at home and awake during the last heating season, which rooms, if any, were not heated during the last heating season, number of times the dwelling was unoccupied for at least one week, number of times pets were let out of the dwelling per day, attitudes toward energy use and conservation and several socio-demographic variables such as age, sex, and total household income. The results of the data analyses showed age to be an important factor for reported indoor temperature and perceived energy efficiency of the dwelling. The results also showed that almost 60% of the ELCAP occupants do not heat one or more rooms during the heating season, and almost 45% of the ELCAP dwellings were unoccupied for at least one week during the reporting period. In terms of the reported allocation of household income for household energy expenses, the results showed that the reported dollar amount spent for the expenses remained relatively constant over income levels.

  14. Sources of polarized neutrons

    International Nuclear Information System (INIS)

    Walter, L.

    1983-01-01

    Various sources of polarized neutrons are reviewed. Monoenergetic source produced with unpolarized or polarized beams, white sources of polarized neutrons, production by transmissions through polarized hydrogen targets and polarized thermal neutronsare discussed, with appropriate applications included. (U.K.)

  15. Neutron delayed choice experiments

    International Nuclear Information System (INIS)

    Bernstein, H.J.

    1986-01-01

    Delayed choice experiments for neutrons can help extend the interpretation of quantum mechanical phenomena. They may also rule out alternative explanations which static interference experiments allow. A simple example of a feasible neutron test is presented and discussed. (orig.)

  16. Neutron radiation capture

    International Nuclear Information System (INIS)

    1986-01-01

    For all stable and experimentally studied radionuclides evaluated data are presented on cross sections of thermal neutrons, on resonance integrals and medium neutron cross sections with energy of 30 KeV. Refs, figs and tabs

  17. Neutron radiography in metallurgy

    International Nuclear Information System (INIS)

    Rant, J.; Ilic, R.

    1977-01-01

    The review surveys microneutronographic and neutron-induced autoradiographic techniques and their applications in metallurgy. A brief survey of applications of neutron radiography as a method of non-destructive testing to some macroscopic problems in metallurgy is included. (author)

  18. A neutron detector for measurement of total neutron production cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Sekharan, K K; Laumer, H; Kern, B D; Gabbard, F [Kentucky Univ., Lexington (USA). Dept. of Physics and Astronomy

    1976-03-01

    A neutron detector has been constructed and calibrated for the accurate measurement of total neutron production cross sections. The detector consists of a polyethylene sphere of 60 cm diameter in which eight /sup 10/BF/sub 3/ counters have been installed radially. The relative efficiency of this detector has been determined for average neutron energies from 30 keV to 1.5 MeV by counting neutrons from /sup 7/Li(p, n)/sup 7/Be. By adjusting the radial positions of the BF/sub 3/ counters in the polyethylene sphere the efficiency for neutron detection was made nearly constant for this energy range. Measurement of absolute efficiency for the same neutron energy range has been done by counting the neutrons from /sup 51/V(p, n)/sup 51/Cr and /sup 57/Fe(p, n)/sup 57/Co reactions and determining the absolute number of residual nuclei produced during the measurement of neutron yield. Details of absolute efficiency measurements and the use of the detector for determination of neutron production cross sections are given.

  19. A neutron detector for measurement of total neutron production cross sections

    International Nuclear Information System (INIS)

    Sekharan, K.K.; Laumer, H.; Kern, B.D.; Gabbard, F.

    1976-01-01

    A neutron detector has been constructed and calibrated for the accurate measurement of total neutron production cross sections. The detector consists of a polyethylene sphere of 60 cm diameter in which eight 10 BF 3 counters have been installed radially. The relative efficiency of this detector has been determined for average neutron energies from 30 keV to 1.5 MeV by counting neutrons from 7 Li(p, n) 7 Be. By adjusting the radial positions of the BF 3 counters in the polyethylene sphere the efficiency for neutron detection was made nearly constant for this energy range. Measurement of absolute efficiency for the same neutron energy range has been done by counting the neutrons from 51 V(p, n) 51 Cr and 57 Fe(p, n) 57 Co reactions and determining the absolute number of residual nuclei produced during the measurement of neutron yield. Details of absolute efficiency measurements and the use of the detector for determination of neutron production cross sections are given. (Auth.)

  20. Occupational therapy publications by Australian authors: A bibliometric analysis.

    Science.gov (United States)

    Brown, Ted; Gutman, Sharon A; Ho, Yuh-Shan

    2018-01-18

    Bibliometrics refers to the collection and measurement of publishing and citation data configurations with the goal of quantifying the influence of scholarly activities. Advantages of bibliometrics include the generation of quantitative indicators of impact, productivity, quality and collaboration. Those parties who benefit from the results of bibliometric analysis include researchers, educators, journal publishers, employers and research funding bodies. A bibliometric analysis was completed of peer-reviewed literature from 1991 to 2015, written by Australian occupational therapists (who were able to be identified as such), and indexed in the Science Citation Index-Expanded (SCI-Expanded) or the Social Sciences Citation Index (SSCI) databases. "Occupational therapy" and "occupational therapist(s)" were used as keywords to search journal articles' publication title, abstract, author details, keywords and KeyWord Plus. Between 1991 and 2015, 752 peer-reviewed journal articles were published by Australian occupational therapy authors. On average, those articles had 3.7 authors, 35 references, and were nine pages in length. The top four journals in which Australian occupational therapists published were Australian Occupational Therapy Journal, British Journal of Occupational Therapy, American Journal of Occupational Therapy, and Physical and Occupational Therapy in Paediatrics. The four Australian institutions that generated the largest number of occupational therapy articles were the University of Queensland, University of Sydney, La Trobe University, and Monash University. The top four countries with whom Australian authors collaborated in manuscript writing were the United Kingdom, United States, Canada and Sweden. The volume of occupational therapy peer-reviewed literature has grown over the last two decades. Australian authors have and continue to make significant contributions to the occupational therapy body of knowledge nationally and internationally. © 2018

  1. Applications of neutron irradiation

    International Nuclear Information System (INIS)

    Ito, Yasuo

    1999-01-01

    The present state of art of applications of neutron irradiation is overviewed taking neutron activation analysis, prompt gamma-ray analysis, fission/alpha track methods, boron neutron capture therapy as examples. What is common among them is that the technologies are nearly matured for wide use by non- nuclear scientists. But the environment around research reactors is not prospective. These applications should be encouraged by incorporating in the neutron science society. (author)

  2. Neutron beams for therapy

    International Nuclear Information System (INIS)

    Kuplenikov, Eh.L.; Dovbnya, A.N.; Telegin, Yu.N.; Tsymbal, V.A.; Kandybej, S.S.

    2011-01-01

    It was given the analysis and generalization of the study results carried out during some decades in many world countries on application of thermal, epithermal and fast neutrons for neutron, gamma-neutron and neutron-capture therapy. The main attention is focused on the practical application possibility of the accumulated experience for the base creation for medical research and the cancer patients effective treatment.

  3. Polarimetric neutron scattering

    International Nuclear Information System (INIS)

    Tasset, F.

    2001-01-01

    Polarimetric Neutron Scattering in introduced, both by, explaining methodological issues and the corresponding instrumental developments. After a short overview of neutron spin polarization and the neutron polarization 3d-vector a pictorial approach of the microscopic theory is used to show how a polarized beam interacts with lattice and magnetic Fourier components in a crystal. Examples are given of using Spherical Neutron Polarimetry (SNP) and the corresponding Cryopad polarimeter for the investigation of non-collinear magnetic structures. (R.P.)

  4. Reactor Neutron Sources

    International Nuclear Information System (INIS)

    Aksenov, V.L.

    1994-01-01

    The present status and the prospects for development of reactor neutron sources for neutron scattering research in the world are considered. The fields of application of neutron scattering relative to synchrotron radiation, the creation stages of reactors (steady state and pulsed) and their position in comparison with spallation neutron sources at present and in the foreseen future are discussed. (author). 15 refs.; 8 figs.; 3 tabs

  5. Properties of neutron sources

    International Nuclear Information System (INIS)

    1987-03-01

    The Conference presentations were divided into sessions devoted to the following topics: white neutron sources, primarily pulsed (6 papers); fast neutron fields (5 papers); Californium-252 prompt fission neutron spectra (14 papers); monoenergetic sources and filtered beams (11 papers); 14 MeV neutron sources (10 papers); selected special application (one paper); and a general interest session (4 papers). Individual abstracts were prepared separately for the papers

  6. Polarized neutron spectrometer

    International Nuclear Information System (INIS)

    Abov, Yu.G.; Novitskij, V.V.; Alfimenkov, V.P.; Galinskij, E.M.; Mareev, Yu.D.; Pikel'ner, L.B.; Chernikov, A.N.; Lason', L.; Tsulaya, V.M.; Tsulaya, M.I.

    2000-01-01

    The polarized neutron spectrometer, intended for studying the interaction of polarized neutrons with nuclei and condensed media in the area of energies from thermal up to several electron-volt, is developed at the IBR-2 reactor (JINR, Dubna). Diffraction on the Co(92%)-Fe(8%) magnetized monocrystals is used for the neutron polarization and polarization analysis. The neutron polarization within the whole energy range equals ∼ 95% [ru

  7. Isotopic neutron sources for neutron activation analysis

    International Nuclear Information System (INIS)

    Hoste, J.

    1988-06-01

    This User's Manual is an attempt to provide for teaching and training purposes, a series of well thought out demonstrative experiments in neutron activation analysis based on the utilization of an isotopic neutron source. In some cases, these ideas can be applied to solve practical analytical problems. 19 refs, figs and tabs

  8. The neutron production rate measurement of an indigenously developed compact D-D neutron generator

    Directory of Open Access Journals (Sweden)

    Das Basanta Kumar

    2013-01-01

    Full Text Available One electrostatic accelerator based compact neutron generator was developed. The deuterium ions generated by the ion source were accelerated by one accelerating gap after the extraction from the ion source and bombarded to a target. Two different types of targets, the drive - in titanium target and the deuteriated titanium target were used. The neutron generator was operated at the ion source discharge potential at +Ve 1 kV that generates the deuterium ion current of 200 mA at the target while accelerated through a negative potential of 80 kV in the vacuum at 1.3×10-2 Pa filled with deuterium gas. A comparative study for the neutron yield with both the targets was carried out. The neutron flux measurement was done by the bubble detectors purchased from Bubble Technology Industries. The number of bubbles formed in the detector is the direct measurement of the total energy deposited in the detector. By counting the number of bubbles the total dose was estimated. With the help of the ICRP-74 neutron flux to dose equivalent rate conversion factors and the solid angle covered by the detector, the total neutron flux was calculated. In this presentation the operation of the generator, neutron detection by bubble detector and estimation of neutron flux has been discussed.

  9. Workshop on polarized neutron filters and polarized pulsed neutron experiments

    International Nuclear Information System (INIS)

    Itoh, Shinichi

    2004-07-01

    The workshop was held in KEK by thirty-three participants on April 26, 2004. The polarized neutron filter method was only discussed. It consists of three parts; the first part was discussed on the polarized neutron methods, the second part on the polarized neutron experiments and the third on the pulse neutron spectrometer and polarized neutron experiments. The six papers were presented such as the polarized 3 He neutron spin filter, neutron polarization by proton polarized filter, soft master and neutron scattering, polarized neutron in solid physics, polarization experiments by chopper spectroscope and neutron polarization system in superHRPD. (S.Y.)

  10. [Lung Cancer as an Occupational Disease].

    Science.gov (United States)

    Baur, X; Woitowitz, H-J

    2016-08-01

    Lung cancer is one of the most frequently encountered cancer types. According to the latest WHO data, about 10 % of this disease are due to occupational exposure to cancerogens. Asbestos is still the number one carcinogen. Further frequent causes include quarz and ionizing radiation (uranium mining). Probable causes of the disease can be identified only with the help of detailed occupational history taken by a medical specialist and qualified exposure assessment. Without clarifying the cause of the disease, there is neither a correct insurance procedure nor compensation for the victim, and furthermore, required preventive measures cannot be initiated. © Georg Thieme Verlag KG Stuttgart · New York.

  11. Spallation neutron sources

    International Nuclear Information System (INIS)

    Fraser, J.S.; Bartholomew, G.A.

    1983-01-01

    The principles and theory of spallation neutron sources are outlined and a comparison is given with other types of neutron source. A summary of the available accelerator types for spallation neutron sources and their advantages and disadvantages is presented. Suitable target materials are discussed for specific applications, and typical target assemblies shown. (U.K.)

  12. Shielded regenerative neutron detector

    International Nuclear Information System (INIS)

    Terhune, J.H.; Neissel, J.P.

    1978-01-01

    An ion chamber type neutron detector is disclosed which has a greatly extended lifespan. The detector includes a fission chamber containing a mixture of active and breeding material and a neutron shielding material. The breeding and shielding materials are selected to have similar or substantially matching neutron capture cross-sections so that their individual effects on increased detector life are mutually enhanced

  13. Prototype Neutron Energy Spectrometer

    International Nuclear Information System (INIS)

    Mitchell, Stephen; Mukhopadhyay, Sanjoy; Maurer, Richard; Wolff, Ronald

    2010-01-01

    The project goals are: (1) Use three to five pressurized helium tubes with varying polyethylene moderators to build a neutron energy spectrometer that is most sensitive to the incident neutron energy of interest. Neutron energies that are of particular interest are those from the fission neutrons (typically around 1-2 MeV); (2) Neutron Source Identification - Use the neutron energy 'selectivity' property as a tool to discriminate against other competing processes by which neutrons are generated (viz. Cosmic ray induced neutron production (ship effect), (a, n) reactions); (3) Determine the efficiency as a function of neutron energy (response function) of each of the detectors, and thereby obtain the composite neutron energy spectrum from the detector count rates; and (4) Far-field data characterization and effectively discerning shielded fission source. Summary of the presentation is: (1) A light weight simple form factor compact neutron energy spectrometer ready to be used in maritime missions has been built; (2) Under laboratory conditions, individual Single Neutron Source Identification is possible within 30 minutes. (3) Sources belonging to the same type of origin viz., (a, n), fission, cosmic cluster in the same place in the 2-D plot shown; and (4) Isotopes belonging to the same source origin like Cm-Be, Am-Be (a, n) or Pu-239, U-235 (fission) do have some overlap in the 2-D plot.

  14. Prototype Neutron Energy Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Stephen Mitchell, Sanjoy Mukhopadhyay, Richard Maurer, Ronald Wolff

    2010-06-16

    The project goals are: (1) Use three to five pressurized helium tubes with varying polyethylene moderators to build a neutron energy spectrometer that is most sensitive to the incident neutron energy of interest. Neutron energies that are of particular interest are those from the fission neutrons (typically around 1-2 MeV); (2) Neutron Source Identification - Use the neutron energy 'selectivity' property as a tool to discriminate against other competing processes by which neutrons are generated (viz. Cosmic ray induced neutron production [ship effect], [a, n] reactions); (3) Determine the efficiency as a function of neutron energy (response function) of each of the detectors, and thereby obtain the composite neutron energy spectrum from the detector count rates; and (4) Far-field data characterization and effectively discerning shielded fission source. Summary of the presentation is: (1) A light weight simple form factor compact neutron energy spectrometer ready to be used in maritime missions has been built; (2) Under laboratory conditions, individual Single Neutron Source Identification is possible within 30 minutes. (3) Sources belonging to the same type of origin viz., (a, n), fission, cosmic cluster in the same place in the 2-D plot shown; and (4) Isotopes belonging to the same source origin like Cm-Be, Am-Be (a, n) or Pu-239, U-235 (fission) do have some overlap in the 2-D plot.

  15. Thermal neutron polarisation

    International Nuclear Information System (INIS)

    Satya Murthy, N.S.; Madhava Rao, L.

    1984-01-01

    The basic principle for the production of polarised thermal neutrons is discussed and the choice of various crystal monochromators surveyed. Brief mention of broad-spectrum polarisers is made. The application of polarised neutrons to the study of magnetisation density distributions in magnetic crystals, the dynamic concept of polarisation, principle and use of polarisation analysis, the neutron spin-echo technique are discussed. (author)

  16. Fundamental neutron physics

    International Nuclear Information System (INIS)

    Deslattes, R.; Dombeck, T.; Greene, G.; Ramsey, N.; Rauch, H.; Werner, S.

    1984-01-01

    Fundamental physics experiments of merit can be conducted at the proposed intense neutron sources. Areas of interest include: neutron particle properties, neutron wave properties, and fundamental physics utilizing reactor produced γ-rays. Such experiments require intense, full-time utilization of a beam station for periods ranging from several months to a year or more

  17. Neutron detection and radiography

    International Nuclear Information System (INIS)

    Bollen, R.H.; Van Esch, R.F.

    1975-01-01

    An improved method of recording neutron images is described which comprises imagewise irradiating with neutrons an intensifying screen containing a gadolinium compound that fluoresces when struck by x-rays and subjecting the fluorescent light pattern resulting from the impact of the neutrons on the screen onto a photographic material. (auth)

  18. Neutron Scattering Software

    Science.gov (United States)

    Home Page | Facilities | Reference | Software | Conferences | Announcements | Mailing Lists Neutron Scattering Banner Neutron Scattering Software A new portal for neutron scattering has just been established sets KUPLOT: data plotting and fitting software ILL/TAS: Matlab probrams for analyzing triple axis data

  19. International Neutron Radiography Newsletter

    DEFF Research Database (Denmark)

    Domanus, Joseph Czeslaw

    1986-01-01

    At the First World Conference on Neutron Radiography i t was decided to continue the "Neutron Radiography Newsletter", published previously by J.P. Barton, as the "International Neutron Radiography Newsletter" (INRNL), with J.C. Doraanus as editor. The British Journal of Non-Destructive Testing...

  20. 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.

  1. Occupational health offshore

    Energy Technology Data Exchange (ETDEWEB)

    Crosbie, A.; Davies, F.

    2002-07-01

    The proceedings contain the 29 papers presented at the conference plus the opening address from the chair of the Health and Safety Commission. The papers in the first session were concerned with policy, strategy and leadership and included a perspective from the offshore industry advisory committee, details of a health planning tool for occupational health assurance and lessons from occupational health management in the offshore sector. The two sessions on the second day dealt with occupational health in the offshore design process and case studies involving physical, chemical and biological agents. Topics included the need to consider occupational health when designing offshore installations, the development of a human factors engineering strategy in petrochemical engineering projects, measuring occupational exposure to hazardous chemicals, implementation of the noise at work regulations, hand arm vibration syndrome and issues with potable water maintenance. The two sessions on the third day were concerned with human factors and psychological health, and well-being and fitness for duty. Topics covered included circadian adaption to shift change in offshore shift workers, managing stress in the offshore environment, the role of employee assistance programmes in organisational stress management, health care and first aid (the revised ACOP), well-being at work, the medical and physical fitness of offshore emergency response rescue team members, the impact of health surveillance and promotion of offshore accident rates, and the implication of safety and heath of the aging of the workforce ion the Norwegian offshore industry.

  2. Zoonoses as occupational diseases

    Directory of Open Access Journals (Sweden)

    Giorgio Battelli

    2008-12-01

    Full Text Available Zoonoses are discussed as occupational diseases, with special reference to animal husbandry and related activities. After quoting some historical references, occupational zoonoses are examined in relation to the evolution of the concept of occupational zoonosis, the involvement of the World Health Organization in this field, their socio-economic significance, the principal working activities, zoonoses of greatest importance (with special reference to the Mediterranean region, the evaluation of damage and risks. An outline is made of the transmission of zoonoses from farm workers to animals and the biological hazards from the environment. The present situation of occupational zoonoses and related risks in industrialised and traditional farming activities are presented and the importance of some emerging and re-emerging zoonoses for the health of workers is highlighted. The author concludes by stressing that the prevention of occupational zoonoses must be implemented jointly by both veterinary and medical services through preventive measures and epidemiological surveillance of human and animal health, risk evaluation, diagnosis of infections and prompt reporting. It is hoped that the future will offer better inter-disciplinary collaboration and that legislation will be timely and better tailored to safeguard working health and safety.

  3. On the e-linac-based neutron yield

    International Nuclear Information System (INIS)

    Bunatyan, G.G.; Nikolenko, V.G.; Popov, A.B.

    2010-01-01

    We treat neutron generating in high atomic number materials due to the photonuclear reactions induced by the Bremsstrahlung of an electron beam produced by linear electron accelerator (e-linac). The dependence of neutron yield on the electron energy and the irradiated sample size is considered for various sample materials. The calculations are performed without resort to the so-called 'numerical Monte Carlo simulation'. The acquired neutron yields are well correlated with the data asserted in investigations performed at a number of the e-linac-driven neutron sources

  4. Radiography and tomography with polarized neutrons

    International Nuclear Information System (INIS)

    Treimer, Wolfgang

    2014-01-01

    Neutron imaging became important when, besides providing impressive radiographic and tomographic images of various objects, physical, quantification of chemical, morphological or other parameters could be derived from 2D or 3D images. The spatial resolution of approximately 50 µm (and less) yields real space images of the bulk of specimens with more than some cm 3 in volume. Thus the physics or chemistry of structures in a sample can be compared with scattering functions obtained e.g. from neutron scattering. The advantages of using neutrons become more pronounced when the neutron spin comes into play. The interaction of neutrons with magnetism is unique due to their low attenuation by matter and because their spin is sensitive to magnetic fields. Magnetic fields, domains and quantum effects such as the Meissner effect and flux trapping can only be visualized and quantified in the bulk of matter by imaging with polarized neutrons. This additional experimental tool is gaining more and more importance. There is a large number of new fields that can be investigated by neutron imaging, not only in physics, but also in geology, archeology, cultural heritage, soil culture, applied material research, magnetism, etc. One of the top applications of polarized neutron imaging is the large field of superconductivity where the Meissner effect and flux pinning can be visualized and quantified. Here we will give a short summary of the results achieved by radiography and tomography with polarized neutrons. - Highlights: • Radiography and tomography with polarized neutrons yield new results concerning the suppressed Meissner effect and magnetic flux trapping. • Suppressed Meissner effect was observed in pure lead samples and niobium. • Trapped magnetic fields in cylindrical Pb samples are squeezed around the rod axis. • The shape and the amount of trapped fields could be determined and quantified

  5. An application of neutron radiography to archaeology

    International Nuclear Information System (INIS)

    Tugrul, B.

    1990-01-01

    Neutron radiography is more useful for certain materials than are the other radiographic techniques. Some neutrons are attenuated by light materials such as water, hydrocarbons and boron, but penetrate through heavy materials such as steel, lead and uranium. The object must be irradiated by neutrons for neutron radiography. The neutron irradiation can take place in a reactor or with a neutron source. The transfer technique relies on the build-up of radioactivity in a foil due to neutron absorption. In this way an activation image is formed in the foil. For this technique, dysprosium ( 164 Dy) and indium ( 115 In) foils can be used. After this irradiation, foils are transferred to a film in the dark-room, the latent image being formed in the film by decay radiation from the foil. The neutron radiography technique has been applied to a sword together with its sheath (inventory number 83/173) (Tugrul and Erdal 1987); a piece of cloth was visible on the handle of the sword. Sword and sheath had become corroded together. The artefact is from the Ikiztepe excavation near the city of Samsun in north Anatolia and belongs to the Early Bronze Age. First, X-ray radiography showed that the sword had been destroyed in large part and was not suitable for conservation and restoration procedures. Second, neutron radiography was carried out. Dysprosium-164 was used for the transfer method as a foil screen and irradiated in the reactor at 100 kW for half an hour. The dysprosium foil remained against the radiographic (Structurix, D-7) film for approximately three half-lives after the irradiation. The neutron radiograph shows the cloth layer continuing towards the bottom of the sheath. Through the cloth, water would have been introduced to the inside of the sheath and this was the main cause of corrosion to the artefact and so of the sword's destruction. (author)

  6. Radiography and tomography with polarized neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Treimer, Wolfgang, E-mail: treimer@helmholtz-berlin.de [University of Applied Sciences, Beuth Hochschule für Technik Berlin, Department Mathematics Physics and Chemistry, Luxemburgerstr. 10, D-13353 Berlin (Germany); Helmholtz Zentrum für Materialien und Energie, Department G – GTOMO, Hahn-Meitner-Platz 1, D-14109 Berlin (Germany)

    2014-01-15

    Neutron imaging became important when, besides providing impressive radiographic and tomographic images of various objects, physical, quantification of chemical, morphological or other parameters could be derived from 2D or 3D images. The spatial resolution of approximately 50 µm (and less) yields real space images of the bulk of specimens with more than some cm{sup 3} in volume. Thus the physics or chemistry of structures in a sample can be compared with scattering functions obtained e.g. from neutron scattering. The advantages of using neutrons become more pronounced when the neutron spin comes into play. The interaction of neutrons with magnetism is unique due to their low attenuation by matter and because their spin is sensitive to magnetic fields. Magnetic fields, domains and quantum effects such as the Meissner effect and flux trapping can only be visualized and quantified in the bulk of matter by imaging with polarized neutrons. This additional experimental tool is gaining more and more importance. There is a large number of new fields that can be investigated by neutron imaging, not only in physics, but also in geology, archeology, cultural heritage, soil culture, applied material research, magnetism, etc. One of the top applications of polarized neutron imaging is the large field of superconductivity where the Meissner effect and flux pinning can be visualized and quantified. Here we will give a short summary of the results achieved by radiography and tomography with polarized neutrons. - Highlights: • Radiography and tomography with polarized neutrons yield new results concerning the suppressed Meissner effect and magnetic flux trapping. • Suppressed Meissner effect was observed in pure lead samples and niobium. • Trapped magnetic fields in cylindrical Pb samples are squeezed around the rod axis. • The shape and the amount of trapped fields could be determined and quantified.

  7. The effective delayed neutron fraction for bare-metal criticals

    International Nuclear Information System (INIS)

    Pearlstein, S.

    1999-01-01

    Given sufficient material, a large number of actinides could be used to form bare-metal criticals. The effective delayed neutron fraction for a bare critical comprised of a fissile material is comparable with the absolute delayed neutron fraction. The effective delayed neutron fraction for a bare critical composed of a fissionable material is reduced by factors of 2 to 10 when compared with the absolute delayed neutron fraction. When the effective delayed neutron fraction is small, the difference between delayed and prompt criticality is small, and extreme caution must be used in critical assemblies of these materials. This study uses an approximate but realistic model to survey the actinide region to compare effective delayed neutron fractions with absolute delayed neutron fractions

  8. In vivo measurement of cadmium in an occupationally-exposed population

    International Nuclear Information System (INIS)

    Ellis, K.J.; Morgan, W.D.; Yasumura, S.; Vartsky, D.; Zanzi, I.; Cohn, S.H.

    1980-01-01

    Exposure to cadmium is recognized as a potentially serious health problem. A number of clinical abnormalities have been observed in workers occupationally exposed to cadmium. Therefore, it is essential that accurate data on body burdens be available in order to formulate dose-response relationships in man. This report describes the present Brookhaven facility for in vivo measurements of cadmium in man and recent results from a field study to a cadmium production plant. The cadmium content of the left kidney and concentration in the liver were measured by prompt-gamma neutron activation analysis in 82 occupationally exposed workers and 10 control subjects. Organ content ranged up to 57 mg in the kidney and up to 120 ppM in the liver for the industrial group. By contrast, the values for the control group ranged from 0.4 to 11.8 mg for the kidney and 0.7 to 7.9 ppM for the liver. The geometric means were 3.7 mg for the kidney and 2.7 ppM for the liver in the control group. When the data were analyzed to provide an estimate of the critical concentration for the kidney, a range of 300 to 400 μg/g for the renal cortex was calculated. These results are compared with the available data in the literature

  9. Occupational exposures in industrial application of radiation during 1999-2008

    International Nuclear Information System (INIS)

    Sanaye, Suresh Shantaram; Baburajan, Sujatha; Pawar, Suresh Ganpat; Nalawade, Shailesh Krishna; Sapra, Balvinder Kaur

    2012-01-01

    Radiation sources are used in various industrial applications like industrial radiograph, industrial irradiation, industrial fluoroscopy, nucleonic gauges, well logging etc., Gamma, beta X-ray as well as neutron sources are used for various applications. Number of radiation workers in this field has increased over the years. Due to operating conditions prevailing during the exposure as well as the strength of the sources used in some of the applications, radiation protection plays an important role in this field. Analysis of doses received by radiation workers in industry provides information on trends of doses as well as adequateness of radiation protection practices followed in this sector. In India, National Occupational Dose Registry System (NODRS) of Radiological Physics and Advisory Division (RPAD), Bhabha Atomic Research Centre (BARC) maintains personnel dose information of monitored radiation workers in the country. Analysis of occupational dose data of industrial radiation workers for last 10 years, i.e., 1999-2008 has been presented in this paper. It is observed that even though there is an increase in monitored radiation workers, percentage of persons receiving radiation exposure has come down during this period. There is also a decrease in the average annual dose as well as the collective dose. Further analysis of sub-categories shows that industrial radiography operations are the main contributor for collective dose (about 77%) followed by well logging and industrial X-ray operations (about 8% each). Thus, in addition to industrial radiography attention is also to be given to operations in these areas. (author)

  10. Quality of life and depression in a population of occupational hand eczema patients

    DEFF Research Database (Denmark)

    Cvetkovski, Rikke Skoet; Zachariae, Robert; Jensen, Hans Henrik

    2006-01-01

    Occupational hand eczema (OHE) is the most frequently recognized occupational disease in Denmark, and despite governmental attempts to reduce exposure to harmful occupational allergens, the number of new cases has remained almost unchanged since the mid-1990s. Some studies have indicated that OHE...

  11. Neutron activation analysis

    International Nuclear Information System (INIS)

    Okada, Yukiko

    2005-01-01

    Trends and progress in neutron activation analysis (NAA) for the period starting in 1999 to 2003 are presented. Numbers of published reports on NAA are decreasing year by year as investigated from the database JST and NUCLEN. Summary reports on the international conferences held on NAA are followed by classifying according to the fields: various measurement techniques and application fields. Specially focused topics are newly developed techniques for measuring trace elements with high sensitivity and high accuracy such as (1) by diminishing the Compton-background gamma-rays using anti-coincidence technique, (2) by using prompt-gamma rays measurement method (PGAA) and (3) by using a gamma-ray detector array (GEMINI), which has succeeded in a simultaneous quantification of 27 elements from a standard rock sample having a weight of only 10 milligrams, and others. These techniques will be applied in the space and earth sciences and medical fields. (S. Ohno)

  12. Parallel Monte Carlo reactor neutronics

    International Nuclear Information System (INIS)

    Blomquist, R.N.; Brown, F.B.

    1994-01-01

    The issues affecting implementation of parallel algorithms for large-scale engineering Monte Carlo neutron transport simulations are discussed. For nuclear reactor calculations, these include load balancing, recoding effort, reproducibility, domain decomposition techniques, I/O minimization, and strategies for different parallel architectures. Two codes were parallelized and tested for performance. The architectures employed include SIMD, MIMD-distributed memory, and workstation network with uneven interactive load. Speedups linear with the number of nodes were achieved

  13. Measuring site occupancy

    DEFF Research Database (Denmark)

    Rogowska-Wrzesinska, Adelina; Wojdyla, Katarzyna; Williamson, James

    2014-01-01

    occupancy of the modification site. We show that, on one hand, heavily modified cysteines are not necessarily involved in the response to oxidative stress. On the other hand residues with low modification level can be dramatically affected by mild oxidative imbalance. We make use of high resolution mass...... peptides corresponding to 90 proteins. Only 6 modified peptides changed significantly under mild oxidative stress. Quantitative information allowed us to determine relative modification site occupancy of each identified modified residue and pin point heavily modified ones. The method proved to be precise...... and sensitive enough to detect and quantify endogenous levels of oxidative stress on proteome-wide scale and brings a new perspective on the role of the modification site occupancy in cellular redox response....

  14. Oscillations in neutron stars

    International Nuclear Information System (INIS)

    Hoeye, Gudrun Kristine

    1999-01-01

    We have studied radial and nonradial oscillations in neutron stars, both in a general relativistic and non-relativistic frame, for several different equilibrium models. Different equations of state were combined, and our results show that it is possible to distinguish between the models based on their oscillation periods. We have particularly focused on the p-, f-, and g-modes. We find oscillation periods of II approx. 0.1 ms for the p-modes, II approx. 0.1 - 0.8 ms for the f-modes and II approx. 10 - 400 ms for the g-modes. For high-order (l → 4) f-modes we were also able to derive a formula that determines II l+1 from II l and II l-1 to an accuracy of 0.1%. Further, for the radial f-mode we find that the oscillation period goes to infinity as the maximum mass of the star is approached. Both p-, f-, and g-modes are sensitive to changes in the central baryon number density n c , while the g-modes are also sensitive to variations in the surface temperature. The g-modes are concentrated in the surface layer, while p- and f-modes can be found in all parts of the star. The effects of general relativity were studied, and we find that these are important at high central baryon number densities, especially for the p- and f-modes. General relativistic effects can therefore not be neglected when studying oscillations in neutron stars. We have further developed an improved Cowling approximation in the non-relativistic frame, which eliminates about half of the gap in the oscillation periods that results from use of the ordinary Cowling approximation. We suggest to develop an improved Cowling approximation also in the general relativistic frame. (Author)

  15. Oscillations in neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Hoeye, Gudrun Kristine

    1999-07-01

    We have studied radial and nonradial oscillations in neutron stars, both in a general relativistic and non-relativistic frame, for several different equilibrium models. Different equations of state were combined, and our results show that it is possible to distinguish between the models based on their oscillation periods. We have particularly focused on the p-, f-, and g-modes. We find oscillation periods of II approx. 0.1 ms for the p-modes, II approx. 0.1 - 0.8 ms for the f-modes and II approx. 10 - 400 ms for the g-modes. For high-order (l (>{sub )} 4) f-modes we were also able to derive a formula that determines II{sub l+1} from II{sub l} and II{sub l-1} to an accuracy of 0.1%. Further, for the radial f-mode we find that the oscillation period goes to infinity as the maximum mass of the star is approached. Both p-, f-, and g-modes are sensitive to changes in the central baryon number density n{sub c}, while the g-modes are also sensitive to variations in the surface temperature. The g-modes are concentrated in the surface layer, while p- and f-modes can be found in all parts of the star. The effects of general relativity were studied, and we find that these are important at high central baryon number densities, especially for the p- and f-modes. General relativistic effects can therefore not be neglected when studying oscillations in neutron stars. We have further developed an improved Cowling approximation in the non-relativistic frame, which eliminates about half of the gap in the oscillation periods that results from use of the ordinary Cowling approximation. We suggest to develop an improved Cowling approximation also in the general relativistic frame. (Author)

  16. Luminosity class of neutron reflectometers

    Energy Technology Data Exchange (ETDEWEB)

    Pleshanov, N.K., E-mail: pnk@pnpi.spb.ru

    2016-10-21

    The formulas that relate neutron fluxes at reflectometers with differing q-resolutions are derived. The reference luminosity is defined as a maximum flux for measurements with a standard resolution. The methods of assessing the reference luminosity of neutron reflectometers are presented for monochromatic and white beams, which are collimated with either double diaphragm or small angle Soller systems. The values of the reference luminosity for unified parameters define luminosity class of reflectometers. The luminosity class characterizes (each operation mode of) the instrument by one number and can be used to classify operating reflectometers and optimize designed reflectometers. As an example the luminosity class of the neutron reflectometer NR-4M (reactor WWR-M, Gatchina) is found for four operation modes: 2.1 (monochromatic non-polarized beam), 1.9 (monochromatic polarized beam), 1.5 (white non-polarized beam), 1.1 (white polarized beam); it is shown that optimization of measurements may increase the flux at the sample up to two orders of magnitude with monochromatic beams and up to one order of magnitude with white beams. A fan beam reflectometry scheme with monochromatic neutrons is suggested, and the expected increase in luminosity is evaluated. A tuned-phase chopper with a variable TOF resolution is recommended for reflectometry with white beams.

  17. Neutron dosimetry using electrochemical etching

    International Nuclear Information System (INIS)

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

    1977-01-01

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

  18. Neutron scattering. Experiment manuals

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2010-07-01

    The following topics are dealt with: The thermal triple axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, neutron polarization analysis with tht time-of-flight spectrometer DNS, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering with the KWS-1 and KWS-2 diffractometers, the very-small-angle neutron scattering diffractrometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  19. Activation neutron detector

    International Nuclear Information System (INIS)

    Ambardanishvili, T.S.; Kolomiitsev, M.A.; Zakharina, T.Y.; Dundua, V.J.; Chikhladze, N.V.

    1976-01-01

    An activation neutron detector made as a moulded and cured composition of a material capable of being neutron-activated is described. The material is selected from a group consisting of at least two chemical elements, a compound of at least two chemical elements and their mixture, each of the chemical elements and their mixture, each of the chemical elements being capable of interacting with neutrons to form radioactive isotopes having different radiation energies when disintegrating. The material capable of being neutron-activated is distributed throughout the volume of a polycondensation resin inert with respect to neutrons and capable of curing. 17 Claims, No Drawings

  20. High energy neutron dosimeter

    International Nuclear Information System (INIS)

    Rai, K.S.F.

    1994-01-01

    A device for measuring dose equivalents in neutron radiation fields is described. The device includes nested symmetrical hemispheres (forming spheres) of different neutron moderating materials that allow the measurement of dose equivalents from 0.025 eV to past 1 GeV. The layers of moderating material surround a spherical neutron counter. The neutron counter is connected by an electrical cable to an electrical sensing means which interprets the signal from the neutron counter in the center of the moderating spheres. The spherical shape of the device allows for accurate measurement of dose equivalents regardless of its positioning. 2 figures

  1. Pulse neutron logging technique

    International Nuclear Information System (INIS)

    Bespalov, D.F.; Dylyuk, A.A.

    1975-01-01

    A new method of neutron-burst logging is proposed, residing in irradiating rocks with fast neutron bursts and registering the integrated flux burst of thermal and/or epithermal neutrons, from the moment of its initiation to that of full absorption. The obtaained value is representative of the rock properties (porosity, hydrogen content). The integrated flux in a burst of thermal and epithermal neutrons can be measured both by way of activation of a reference sample of a known chemical composition during the neutron burst and by recording the radiation of induced activity of the sample within an interval between two bursts. The proposed method features high informative value, accuracy and efficiency

  2. Neutron scattering. Experiment manuals

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2012-01-01

    The following topics are dealt with: The thermal triple-axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, the neutron polarization analyzer DNS, the neutron spin-echo spectrometer J-NSE, the small-angle neutron diffractometers KWS-1/-2, the very-small-angle neutron diffractometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  3. Neutron techniques in Safeguards

    International Nuclear Information System (INIS)

    Zucker, M.S.

    1982-01-01

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

  4. Nanosecond neutron generator

    International Nuclear Information System (INIS)

    Lobov, S.I.; Pavlovskaya, N.G.; Pukhov, S.P.

    1991-01-01

    High-voltage nanosecond neutron generator for obtaining neutrons in D-T reaction is described. Yield of 6x10 6 neutron/pulse was generated in a sealed gas-filled diode with a target on the cathode by accelerating pulse voltage of approximately 0.5 MV and length at half-height of 0.5 ns and deuterium pressure of 6x10 -2 Torr. Ways of increasing neutron yield and possibilities of creating generators of nanosecond neutron pulses with great service life are considered

  5. Principles of neutron reflection

    International Nuclear Information System (INIS)

    Felcher, G.P.

    1988-08-01

    Neutron reflection is perhaps the most developed branch of slow neutrons optics, which in itself is a direct consequence of the undulatory nature of the neutron. After reviewing the basic types of interactions (nuclear and magnetic) between neutrons and matter, the formalism is introduced to calculate the reflectivity from a sample composed of stacked flat layers and, inversely, to calculate the stacking from reflectivity measurements. Finally, a brief survey of the applications of neutron reflection is given, both in technology and in fundamental research. 32 refs., 6 figs

  6. 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.

  7. Neutron scattering. Experiment manuals

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2010-01-01

    The following topics are dealt with: The thermal triple axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, neutron polarization analysis with tht time-of-flight spectrometer DNS, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering with the KWS-1 and KWS-2 diffractometers, the very-small-angle neutron scattering diffractrometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)

  8. Determination of the Jet Neutron Rate and Fusion Power using the Magnetic Proton Recoil Neutron Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Sjoestrand, Henrik

    2003-01-01

    In this thesis a new independent method has been developed to enable precise measurements of neutron yields and rates from fusion plasmas and thereby determining the fusion power and fusion energy. The new method, together with the associated diagnostics, can provide information of great importance to present and future high fusion yield experiments, such as the Joint European Torus (JET) tokamak and the International Thermonuclear Experiment Reactor (ITER). The method has been applied to data from high fusion rate experiments from the tritium campaign at JET. By using the count-rate from the Magnetic Proton Recoil (MPR) neutron spectrometer the number of neutrons in the spectrometer's line of sight has been calculated. To be able to do this, all relevant factors between the plasma and the instrument have been evaluated. The number of neutrons in the MPR line of sight has been related to the total number of produced neutrons in the plasma by using information on the neutron emission profile. The achieved results have been compared with other JET neutron diagnostic data and the agreement is shown to be very good.

  9. Occupational reproductive health risks.

    Science.gov (United States)

    Filkins, K; Kerr, M J

    1993-01-01

    The potentially harmful effects on women of certain workplace exposures are widely appreciated, and steps to control these have included legislative efforts such as right-to-know laws of well as corporate policies mandating selective restriction of fertile women, which are illegal under federal civil rights laws. This chapter reviews the various occupational health risks reproductive women face in the workplace but also considers the effects of other genetic, medical, social, infectious, and environmental factors which may be of even greater concern than most occupational factors.

  10. Occupational lifting of heavy loads and preterm birth:

    DEFF Research Database (Denmark)

    Runge, Stine Bjerrum; Pedersen, Jacob Krabbe; Svendsen, Susanne Wulff

    2013-01-01

    To examine the association between occupational lifting during pregnancy and preterm birth. The risk of preterm birth was estimated for total burden lifted per day and number of medium and heavy loads lifted per day.......To examine the association between occupational lifting during pregnancy and preterm birth. The risk of preterm birth was estimated for total burden lifted per day and number of medium and heavy loads lifted per day....

  11. Radiation exams in occupational medical evaluations

    International Nuclear Information System (INIS)

    Gelsleichter, A.M.; Hunh, A.; Nandi, D.M.

    2017-01-01

    Introduction: In occupational medicine, medical care must be geared toward the prevention of worker health. However, occupational medical exams often seek only through rigorous screening, reduce absenteeism, and thus increase productivity. To meet this goal, many institutions include radiological examinations indiscriminately in their medical and expert evaluations, contrary to the principle of justification. Objective: To provide a reflection about the presence of radiological exams in occupational medical evaluations. Methodology: Literary review including legislation related to the research topic. Results: Portaria 453/98 ANVISA prohibits the performance of radiological examinations for employment or expert purposes, except in cases where the exam may bring a benefit to the health of the individual examined or to society. However, in some situations the Norma Regulamentadora number 7 of the Ministry of Labor and Employment provides for radiological exams as a parameter for monitoring occupational exposure. Article 168 of the Consolidation of Labor Laws also prescribes that additional examinations may be required, at the medical discretion, to determine the physical and mental fitness of the employee for the job. Conclusion: Although there are legal provisions that prohibit and others that allow radiological exams in medical occupational evaluations, companies and institutions should take into account that any radiological exam has a risk involved and should not request them in a compulsory and indiscriminate manner. Radiological exams are only permissible to elucidate the diagnostic hypothesis produced by clinical evaluation, in order to provide a real benefit for the individual

  12. [Occupational injury, a public health priority].

    Science.gov (United States)

    Benavides, Fernando G; Delclos, Jordi; Benach, Joan; Serra, Consol

    2006-01-01

    The aim of this review is to stimulate new ideas and actions for the prevention of this important public health problem. In 2002 and 2003, respectively, the number of non-fatal occupational injuries was 971,406 and 906,638. Thus, every day in Spain there are more than 2500 non-fatal and between 2 and 3 fatal occupational injuries. Although the profile of the at-risk worker population has changed greatly over the past decade, both quantitatively and qualitatively, the risk of occupational injury still centers on blue collar workers, whether qualified or nonqualified, in the primary and secondary sectors of economic activity. The most common mechanisms of occupational injuries are overexertion for non-fatal injuries and traffic-related for fatal events. The adverse health consequences of new types of employment, which emphasize flexibility and deregulation of the labour market, are exemplified by the association between temporary employment and increased risk of occupational injury. New injury prevention programs have emerged in the last decade, but they appear to have had limited impact. Preventive activities should focus both on working conditions at the company level (micro) as well as on employment and industrial public policies (macro). Greater evaluation is needed of these latter policies.

  13. Direct ion storage dosimetry systems for photon, beta and neutron radiation with instant readout capabilities

    International Nuclear Information System (INIS)

    Wernli, C.; Kahilainen, J.

    2001-01-01

    The direct ion storage (DIS) dosemeter is a new type of electronic dosemeter from which the dose information for both H p (10) and H p (0.07) can be obtained instantly at the workplace by using an electronic reader unit. The number of readouts is unlimited and the stored information is not affected by the readout procedure. The accumulated dose can also be electronically reset by authorised personnel. The DIS dosemeter represents a potential alternative for replacing the existing film and thermoluminescence dosemeters (TLDs) used in occupational monitoring due to its ease of use and low operating costs. The standard version for normal photon and beta dosimetry, as well as a developmental version for neutron dosimetry, have been characterised in several field studies. Two new small size variations are also introduced including a contactless readout device and a militarised version optimised for field use. (author)

  14. Thermal neutron moderating device

    International Nuclear Information System (INIS)

    Takigami, Hiroyuki.

    1995-01-01

    In a thermal neutron moderating device, superconductive coils for generating magnetic fields capable of applying magnetic fields vertical to the longitudinal direction of a thermal neutron passing tube, and superconductive coils for magnetic field gradient for causing magnetic field gradient in the longitudinal direction of the thermal neutron passing tube are disposed being stacked at the outside of the thermal neutron passing tube. When magnetic field gradient is present vertically to the direction of a magnetic moment, thermal neutrons undergo forces in the direction of the magnetic field gradient in proportion to the magnetic moment. Then, the magnetic moment of the thermal neutrons is aligned with the direction vertical to the passing direction of the thermal neutrons, to cause the magnetic field gradient in the passing direction of the thermal neutrons. The speed of the thermal neutrons can be optionally selected and the wavelength can freely be changed by applying forces to the thermal neutrons and changing the extent and direction of the magnetic field gradient. Superconductive coils are used as the coils for generating magnetic fields and the magnetic field gradient in order to change extremely high energy of the thermal neutrons. (N.H.)

  15. Development of advanced radiation monitors for pulsed neutron fields

    CERN Document Server

    AUTHOR|(CDS)2081895

    The need of radiation detectors capable of efficiently measuring in pulsed neutron fields is attracting widespread interest since the 60s. The efforts of the scientific community substantially increased in the last decade due to the increasing number of applications in which this radiation field is encountered. This is a major issue especially at particle accelerator facilities, where pulsed neutron fields are present because of beam losses at targets, collimators and beam dumps, and where the correct assessment of the intensity of the neutron fields is fundamental for radiation protection monitoring. LUPIN is a neutron detector that combines an innovative acquisition electronics based on logarithmic amplification of the collected current signal and a special technique used to derive the total number of detected neutron interactions, which has been specifically conceived to work in pulsed neutron fields. Due to its special working principle, it is capable of overcoming the typical saturation issues encountere...

  16. Atlas of neutron resonances

    CERN Document Server

    Mughabghab, Said

    2018-01-01

    Atlas of Neutron Resonances: Resonance Properties and Thermal Cross Sections Z= 1-60, Sixth Edition, contains an extensive list of detailed individual neutron resonance parameters for Z=1-60, as well as thermal cross sections, capture resonance integrals, average resonance parameters and a short survey of the physics of thermal and resonance neutrons. The long introduction contains: nuclear physics formulas aimed at neutron physicists; topics of special interest such as valence neutron capture, nuclear level density parameters, and s-, p-, and d-wave neutron strength functions; and various comparisons of measured quantities with the predictions of nuclear models, such as the optical model. As in the last edition, additional features have been added to appeal to a wider spectrum of users. These include: spin-dependent scattering lengths that are of interest to solid-state physicists, nuclear physicists and neutron evaluators; calculated and measured Maxwellian average 5-keV and 30-keV capture cross sections o...

  17. Neutron image intensifier tubes

    International Nuclear Information System (INIS)

    Verat, M.; Rougeot, H.; Driard, B.

    1983-01-01

    The most frequently used techniques in neutron radiography employ a neutron converter consisting of either a scintillator or a thin metal sheet. The radiation created by the neutrons exposes a photographic film that is in contact with the converter: in the direct method, the film is exposed during the time that the object is irradiated with neutrons; in the transfer method, the film is exposed after the irradiation of the object with neutrons. In industrial non-destructive testing, when many identical objects have to be checked, these techniques have several disadvantages. Non-destructive testing systems without these disadvantages can be constructed around neutron-image intensifier tubes. A description and the operating characteristics of neutron-image intensifier tubes are given. (Auth.)

  18. Methods of neutron spectrometry

    International Nuclear Information System (INIS)

    Doerschel, B.

    1981-01-01

    The different methods of neutron spectrometry are based on the direct measurement of neutron velocity or on the use of suitable energy-dependent interaction processes. In the latter case the measuring effect of a detector is connected with the searched neutron spectrum by an integral equation. The solution needs suitable unfolding procedures. The most important methods of neutron spectrometry are the time-of-flight method, the crystal spectrometry, the neutron spectrometry by use of elastic collisions with hydrogen nuclei, and neutron spectrometry with the aid of nuclear reactions, especially of the neutron-induced activation. The advantages and disadvantages of these methods are contrasted considering the resolution, the measurable energy range, the sensitivity, and the experimental and computational efforts. (author)

  19. Neutrons as a probe

    International Nuclear Information System (INIS)

    Iizumi, Masashi

    1993-01-01

    As an introduction to the symposium a brief overview will be given about the features of neutrons as a probe. First it will be pointed out that the utilization of neutrons as a probe for investigating the structural and dynamical properties of condensed matters is a benign gift eventuated from the release of atomic energy initiated by Enrico Fermi exactly half century ago. Features of neutrons as a probe are discussed in accordance with the four basic physical properties of neutrons as an elementary particle; (1) no electric charge (the interaction with matter is nuclear), (2) the mass of neutron is 1 amu, (3) spin is 1/2 and (4) neutrons have magnetic dipole moment. Overview will be given on the uniqueness of neutrons as a probe and on the variety in the way they are used in the wide research area from the pure science to the industrial applications. (author)

  20. Neutron response study

    International Nuclear Information System (INIS)

    Endres, G.W.R.; Fix, J.J.; Thorson, M.R.; Nichols, L.L.

    1981-01-01

    Neutron response of the albedo type dosimeter is strongly dependent on the energy of the incident neutrons as well as the moderating material on the backside of the dosimeter. This study characterizes the response of the Hanford dosimeter for a variety of neutron energies for both a water and Rando phantom (a simulated human body consisting of an actual human skeleton with plastic for body muscles and certain organs). The Hanford dosimeter response to neutrons of different energies is typical of albedo type dosimeters. An approximate two orders of magnitude difference in response is observed between neutron energies of 100 keV and 10 MeV. Methods were described to compensate for the difference in dosimeter response between a laboratory neutron spectrum and the different spectra encountered at various facilities in the field. Generally, substantial field support is necessary for accurate neutron dosimetry

  1. Occupational stress and related factors among surgical residents in Korea.

    Science.gov (United States)

    Kang, Sanghee; Jo, Hye Sung; Boo, Yoon Jung; Lee, Ji Sung; Kim, Chong Suk

    2015-11-01

    The application rate for surgical residents in Korea has continuously decreased over the past few years. The demanding workload and the occupational stress of surgical training are likely causes of this problem. The aim of this study was to investigate occupational stress and its related factors in Korean surgical residents. With the support of the Korean Surgical Society, we conducted an electronic survey of Korean surgical residents related to occupational stress. We used the Korean Occupational Stress Scale (KOSS) to measure occupational stress. We analyzed the data focused on the stress level and the factors associated with occupational stress. The mean KOSS score of the surgical residents was 55.39, which was significantly higher than that of practicing surgeons (48.16, P occupation rate and exercise were all significantly associated with KOSS score. Surgical residents have high occupational stress compared to practicing surgeons and other professionals. Their mean number of assigned patients, resident recruitment rate and exercise were all significantly associated with occupational stress for surgical residents.

  2. Determination of the Neutron Flux in the Reactor Zones with the Strong Neutron Absorption and Leakage

    International Nuclear Information System (INIS)

    Ljubenov, V.; Milosevic, M.

    2004-11-01

    The procedures for the numerical and experimental determination of the neutron flux in the zones with the strong neutron absorption and leakage are described in this paper. Numerical procedure is based on the application of the SCALE-4.4a code system where the Dancoff factors are determined by the VEGA2DAN code. Two main parts of the experimental methodology are measurement of the activity of irradiated foils and determination of the averaged neutron absorption cross-section in the foils by the SCALE-4.4a calculation procedure. The proposed procedures have been applied for the determination of the neutron flux in the internal neutron converter used with the RB reactor core configuration number 114. (author)

  3. Community occupational therapists' clinical reasoning: identifying tacit knowledge.

    Science.gov (United States)

    Carrier, Annie; Levasseur, Mélanie; Bédard, Denis; Desrosiers, Johanne

    2010-12-01

    Occupational therapy interventions in the community, a fast expanding practice setting, are central to an important social priority, the ability to live at home. These interventions generally involve only a small number of home visits, which aim at maximising the safety and autonomy of community-dwelling clients. Knowing how community occupational therapists determine their interventions, i.e. their clinical reasoning, can improve intervention efficacy. However, occupational therapists are often uninformed about and neglect the importance of clinical reasoning, which could underoptimise their interventions.   To synthesise current knowledge about community occupational therapists' clinical reasoning.   A scoping study of the literature on community occupational therapists' clinical reasoning was undertaken.   Fifteen textbooks and 25 articles, including six focussing on community occupational therapists' clinical reasoning, were reviewed. Community occupational therapists' clinical reasoning is influenced by internal and external factors. Internal factors include past experiences, expertise and perceived complexity of a problem. One of the external factors, practice context (e.g. organisational or cultural imperatives, physical location of intervention), particularly shapes community occupational therapists' clinical reasoning, which is interactive, complex and multidimensional. However, the exact influence of many factors (personal context, organisational and legal aspects of health care, lack of resources and increased number of referrals) remains unclear.   Further studies are needed to understand better the influence of internal and external factors. The extent to which these factors mould the way community occupational therapists think and act could have a direct influence on the services they provide to their clients. © 2010 The Authors. Australian Occupational Therapy Journal © 2010 Australian Association of Occupational Therapists.

  4. Occupational Structure in European Countries: What do Forecasts Predict?

    Directory of Open Access Journals (Sweden)

    Nina Vishnevskaya

    2017-12-01

    Full Text Available This paper analyzes the future occupational structure of the labour force in European members of the Organisation for Co-operation and Development (OECD. Occupational structure forecasts allow researchers to evaluate the quality of job openings and, consequently, overall future labour market performance. Identification of demand for certain occupations in Europe can facilitate assessment of whether processes occurring in the Russian labour market are consistent with global trends. The paper discusses the methodology of labour force forecasting and basic research approaches to the prediction of occupational structure changes. It emphasizes the dynamics of demand for representatives of certain occupations in Europe by identifying the fastest growing and declining occupations and suggests possible reasons for changing demand. The paper demonstrates that the main occupational trend over the next decade will consist in the increasing importance of professionals, as well as technicians and associate professionals. The increase in demand for health professionals and representatives of occupations providing scientific and technological innovation will be most significant. At the same time, it is expected that demand for elementary occupations will also rise. This process will evolve simultaneously with the decrease in the total number of skilled and semi-skilled blue-collar occupations due to globalization and the reduction of industrial production in developed economies. The ongoing “mechanization” of many job functions will not eliminate the need for occupations such as cleaners, labourers, domestic servants or personal workers. The need for these jobs allow employees with low levels of education to enter the labour market rather than depending on the social benefit system. Another tendency for all countries with developed economies will be reduced demand for many whitecollar occupations as modern computer technologies and the automation of many

  5. Enabling occupation at the end of life: A literature review.

    Science.gov (United States)

    Mills, Katherine; Payne, Angela

    2015-12-01

    Occupation, or meaningful activity, can contribute to the well-being and quality of life of all individuals. It is thus a logical tautology that occupation should be enabled for those at the end of life. Our present review examines current provision of these processes by Occupational Therapist, who can be much-valued members of multidisciplinary palliative care teams. Following a literature search and critical selection, 10 global papers were identified examining occupation and occupational therapy at the end of life in the acute, hospice, and community environments. Universally, there appeared to be a dearth of therapists working in end-of-life care. Provision of palliative care in hospitals was found to be compensatory or rehabilitative. Hospice therapy emerged as pleasingly occupational, though the number of hospice places was disappointingly few. Community literature was sparse, so it proved challenging to draw definitive conclusions. Promising research refracted light on occupation at home; however, it also revealed stretched domiciliary services, where clients are not well informed about the potential scope of occupational therapy. A "good death" involving a quality end-of-life experience is the foundational goal overarching all therapy and medicine in the provision of palliative care. Arguably, an occupation-focused approach provided by therapists meets client needs to enable meaningful experiences in the limited time left to them. Current occupational therapy practice environments are not necessarily achieving these goals in commensurate fashion. There is a need to promote the role of occupational therapy and circumscribe what therapists can offer. Further research is necessitated across all environments and future funding for therapist positions in palliative teams. End-of-life care can be complex and challenging; however, therapists can facilitate fulfillment of client-centered occupational goals. In engaging with personally constructed nuances of meaning

  6. Neutron gauging applications using a small 252Cf source

    International Nuclear Information System (INIS)

    Helf, S.

    1975-01-01

    The use of a small 252 Cf source, in the 3 to 4 μg range, for neutron gauging applications is described. Emphasis is placed on determination of low concentrations of moisture in homogeneous media, e.g., solvents, explosives, dried food products, etc. and on measurement of charge or fill weight of hydrogenous materials in sealed items, e.g., propellant in a cartridge case. Both moderation of fast neutrons and attenuation of thermalized neutrons have been explored for these applications. Parameters related to the attainment of optimum sensitivity for each method are discussed. Fast neutron moderation is superior for low level moisture measurement whereas thermal neutron attenuation is more sensitive for ''neutron weighing'' applications. Under optimum conditions, sensitivity for moisture measurement approaches 0.1 weight percent whereas ''neutron weighing'' can detect changes in hydrogeneous material content as little as a fraction of a gram. Examples are given for each technique. A number of different thermal neutron detectors are compared for neutron gauging measurements. A 6 LiI (Eu) scintillation detector is judged to be superior with regard to high thermal neutron detection efficiency and low fast neutron and gamma ray response. In this study, emphasis is placed on the use of simple, portable equipment easily adaptable to field or plant use and for on-line process or quality control. (U.S.)

  7. Study of a nTHGEM-based thermal neutron detector

    Science.gov (United States)

    Li, Ke; Zhou, Jian-Rong; Wang, Xiao-Dong; Xiong, Tao; Zhang, Ying; Xie, Yu-Guang; Zhou, Liang; Xu, Hong; Yang, Gui-An; Wang, Yan-Feng; Wang, Yan; Wu, Jin-Jie; Sun, Zhi-Jia; Hu, Bi-Tao

    2016-07-01

    With new generation neutron sources, traditional neutron detectors cannot satisfy the demands of the applications, especially under high flux. Furthermore, facing the global crisis in 3He gas supply, research on new types of neutron detector as an alternative to 3He is a research hotspot in the field of particle detection. GEM (Gaseous Electron Multiplier) neutron detectors have high counting rate, good spatial and time resolution, and could be one future direction of the development of neutron detectors. In this paper, the physical process of neutron detection is simulated with Geant4 code, studying the relations between thermal conversion efficiency, boron thickness and number of boron layers. Due to the special characteristics of neutron detection, we have developed a novel type of special ceramic nTHGEM (neutron THick GEM) for neutron detection. The performance of the nTHGEM working in different Ar/CO2 mixtures is presented, including measurements of the gain and the count rate plateau using a copper target X-ray source. A detector with a single nTHGEM has been tested for 2-D imaging using a 252Cf neutron source. The key parameters of the performance of the nTHGEM detector have been obtained, providing necessary experimental data as a reference for further research on this detector. Supported by National Natural Science Foundation of China (11127508, 11175199, 11205253, 11405191), Key Laboratory of Neutron Physics, CAEP (2013DB06, 2013BB04) and CAS (YZ201512)

  8. Study of the structure of yrast bands of neutron-rich 114-124Pd isotopes

    Science.gov (United States)

    Chaudhary, Ritu; Devi, Rani; Khosa, S. K.

    2018-02-01

    The projected shell model calculations have been carried out in the neutron-rich 114-124Pd isotopic mass chain. The results have been obtained for the deformation systematics of E(2+1) and E(4+1)/E({2}+1) values, BCS subshell occupation numbers, yrast spectra, backbending phenomena, B( E2) transition probabilities and g-factors in these nuclei. The observed systematics of E(2+1) values and R_{42} ratios in the 114-124Pd isotopic mass chain indicate that there is a decrease of collectivity as the neutron number increases from 68 to 78. The occurrence of backbending in these nuclei as well as the changes in the calculated B( E2) transition probabilities and g -factors predict that there are changes in the structure of yrast bands in these nuclei. These changes occur at the spin where there is crossing of g-band by 2-qp bands. The predicted backbendings and predicted values of B( E2)s and g-factors in some of the isotopes need to be confirmed experimentally.

  9. Neutron diffraction studies of magnetic materials

    International Nuclear Information System (INIS)

    James, W.J.

    1987-01-01

    The ability of neutron diffraction in determining the nature and extent of magnetic ordering is illustrated for the intermetallic compounds, Y/sub 6/(Fe,Mn)/sub 23/ and ErFe/sub 3/. Substitution with other 3d transition metals influences the Fe-Fe exchange forces such as to alter, sometimes considerably, the magnetic properties, e.g., local site magnetic anisotropies in Er)Fe,Ni)/sub 3/ and thermal expansion anomalies in the R/sub 2/)Fe,Co)/sub 14/B compounds. When the 3d atoms are near neighbors in the periodic chart, their nuclear scattering lengths for neutrons are sufficiently different to permit the detection of preferential occupation of the several nonequivalent crystallographic 3d metal sites, i.e., atomic ordering, present in the R/sub 6/M/sub 23/, and R/sub 2/Fe/sub 14/B structures

  10. Latest developments of neutron scattering instrumentation at the Juelich Centre for Neutron Science

    International Nuclear Information System (INIS)

    Ioffe, Alexander

    2013-01-01

    Jülich Centre for Neutron Science (JCNS) is operating a number of world-class neutron scattering instruments situated at the most powerful and advanced neutron sources (FRM II, ILL and SNS) and is continuously undertaking significant efforts in the development and upgrades to keep this instrumentation in line with the continuously changing scientific request. These developments are mostly based upon the latest progress in neutron optics and polarized neutron techniques. For example, the low-Q limit of the suite of small angle-scattering instruments has been extended to 4·10 -5 Å -1 by the successful use of focusing optics. A new generation of correction elements for the neutron spin-echo spectrometer has allowed for the use of the full field integral available, thus pushing further the instrument resolution. A significant progress has been achieved in the developments of 3 He neutron spin filters for purposes of the wide-angle polarization analysis for off-specular reflectometry and (grazing incidence) small-angle neutron scattering, e.g. the on-beam polarization of 3 He in large cells is allowing to achieve a high neutron beam polarization without any degradation in time. The wide Q-range polarization analysis using 3 He neutron spin filters has been implemented for small-angle neutron scattering that lead to the reduction up to 100 times of the intrinsic incoherent background from non-deuterated biological molecules. Also the work on wide-angle XYZ magnetic cavities (Magic PASTIS) will be presented. (author)

  11. Synthetic biology and occupational risk.

    Science.gov (United States)

    Howard, John; Murashov, Vladimir; Schulte, Paul

    2017-03-01

    Synthetic biology is an emerging interdisciplinary field of biotechnology that involves applying the principles of engineering and chemical design to biological systems. Biosafety professionals have done an excellent job in addressing research laboratory safety as synthetic biology and gene editing have emerged from the larger field of biotechnology. Despite these efforts, risks posed by synthetic biology are of increasing concern as research procedures scale up to industrial processes in the larger bioeconomy. A greater number and variety of workers will be exposed to commercial synthetic biology risks in the future, including risks to a variety of workers from the use of lentiviral vectors as gene transfer devices. There is a need to review and enhance current protection measures in the field of synthetic biology, whether in experimental laboratories where new advances are being researched, in health care settings where treatments using viral vectors as gene delivery systems are increasingly being used, or in the industrial bioeconomy. Enhanced worker protection measures should include increased injury and illness surveillance of the synthetic biology workforce; proactive risk assessment and management of synthetic biology products; research on the relative effectiveness of extrinsic and intrinsic biocontainment methods; specific safety guidance for synthetic biology industrial processes; determination of appropriate medical mitigation measures for lentiviral vector exposure incidents; and greater awareness and involvement in synthetic biology safety by the general occupational safety and health community as well as by government occupational safety and health research and regulatory agencies.

  12. Occupational dose trends in Tanzania

    International Nuclear Information System (INIS)

    Muhogora, W.E.; Nyanda, A.M.; Ngaile, J.E.; Lema, U.S.

    1998-01-01

    This paper describes the present status of occupational radiation exposure of monitored workers in Tanzania from 1986 to 1997. The analysis of dose records observes over this period, a fluctuating trend both in the individual and collective doses. The trend is more related to the fluctuations of the number of radiation workers than to the possible radiation safety changes of the working conditions. It has been found that, the maximum annual dose for the worker in all work categories was about 18 mSv y -1 . This suggests that the occupational radiation exposure in all practices satisfies the current dose limitation system. The national exposure summary shows that, the highest collective dose of 12.8 man-Sv which is 90% of the total collective dose, was due to medical applications. The applications in industry and research had a contribution of nearly 0.8 and 0.7 man-Sv respectively. From the professional point of view, the medical diagnostic radiographers received the highest collective dose of 11.2 man-Sv. Although the medical physicists recorded the minimum collective dose of nearly 0.07 man-Sv, the data shows that this profession received the highest mean dose of about 33 mSv in 12 years. Some achievements of the personnel monitoring services and suggestions for future improvement are pointed out. (author)

  13. Occupant Controlled Lighting

    DEFF Research Database (Denmark)

    Logadóttir, Ásta

    2011-01-01

    preferences for correlated colour temperature (CCT). The results suggest that the method of adjustment, previously used in the lighting literature, is not adequate to generalize about occupant preferences for illuminance or CCT. Factors that influence occupants’ lighting preference when applying the method...

  14. Occupational Burnout among Librarians.

    Science.gov (United States)

    Haack, Mary; And Others

    1984-01-01

    Outlines stages of occupational burnout (enthusiasm, stagnation, frustration, apathy) and begins empirical assessment of burnout syndrome among librarians and other information professionals. Results of pilot survey conducted at one-day conference on reference service using two measures (Staff Burnout Scale for Health Professionals, projective…

  15. Occupational Therapy (For Parents)

    Science.gov (United States)

    ... Fitness Diseases & Conditions Infections Drugs & Alcohol School & Jobs Sports Expert Answers (Q&A) Staying Safe Videos for ... Occupational therapists might: help kids work on fine motor skills so they ... maintain positive behaviors in all environments (e.g., instead of hitting ...

  16. Hospitality Occupations. Curriculum Guide.

    Science.gov (United States)

    California State Dept. of Education, Sacramento. Bureau of Homemaking Education.

    This curriculum guide on the hospitality occupations was developed to help secondary and postsecondary home economics teachers prepare individuals for entry-level jobs in the hospitality industry. The content is in seven sections. The first section presents organizational charts of a medium-size hotel, food and beverage division, housekeeping and…

  17. Occupational chronic obstructive pulmonary disease

    DEFF Research Database (Denmark)

    Omland, Oyvind; Würtz, Else Toft; Aasen, Tor Børvig

    2014-01-01

    Occupational-attributable chronic obstructive pulmonary disease (COPD) presents a substantial health challenge. Focusing on spirometric criteria for airflow obstruction, this review of occupational COPD includes both population-wide and industry-specific exposures....

  18. Occupational Safety and Health Administration

    Science.gov (United States)

    ... Twitter Instagram RSS Subscribe Occupational Safety and Health Administration English | Spanish MENU OSHA English | Spanish Search A ... STATES DEPARTMENT OF LABOR Occupational Safety and Health Administration 200 Constitution Ave., NW, Washington, DC 20210 800- ...

  19. Occupational Therapy's Role with Autism

    Science.gov (United States)

    Fact Sheet Occupational Therapy’s Role with Autism Autism is a lifelong condition associated with a varied course from early childhood through adulthood. Occupational therapy practitioners are distinctly qualified to ...

  20. Mission Critical Occupation (MCO) Charts

    Data.gov (United States)

    Office of Personnel Management — Agencies report resource data and targets for government-wide mission critical occupations and agency specific mission critical and/or high risk occupations. These...