WorldWideScience

Sample records for neutron absorber techniques

  1. Recoverable neutron absorbers

    International Nuclear Information System (INIS)

    Keay, R.T.; Williams, J.A.

    1982-01-01

    In the reprocessing of irradiated nuclear fuel elements the nuclear fuel material is separated from the material which forms the remainder of the elements by dissolving the nuclear fuel material in nitric acid. Neutron absorbers are added to control criticality. The neutron absorbers comprise pellets each having a core of neutron absorbing material encased in a sheath of a material which is resistant to attack by acid, the core or sheath being magnetic. The sheath protects the core of neutron absorbing material from attack by the acid and the magnetic content of the core or sheath enables the absorbers to be recovered for reuse by magnetic separation techniques. (author)

  2. Neutron absorbing article

    International Nuclear Information System (INIS)

    Naum, R.G.; Owens, D.P.; Dooker, G.I.

    1981-01-01

    A neutron-absorbing article suitable for use in spent fuel racks is described. It comprises boron carbide particles, diluent particles, and a phenolic polymer cured to a continuous matrix. The diluent may be silicon carbide, graphite, amorphous carbon, alumina, or silica. The combined boron carbide-diluent phase contains no more than 2 percent B 2 O 3 , and the neutron-absorbing article contains from 20 to 40 percent phenol resin. The ratio of boron carbide to diluent particles is in the range 1:9 to 9:1

  3. Neutron absorbing article

    International Nuclear Information System (INIS)

    Naum, R.G.; Owens, D.P.; Dooher, G.I.

    1979-01-01

    A neutron absorbing article, in flat plate form and suitable for use in a storage rack for spent fuel, includes boron carbide particles, diluent particles and a solid, irreversibly cured phenolic polymer cured to a continuous matrix binding the boron carbide and diluent particles. The total conent of boron carbide and diluent particles is a major proportion of the article and the content of cured phenolic polymer present is a minor proportion. By regulation of the ratio of boron carbide particles to diluent particles, normally within the range of 1:9 and 9:1 and preferably within the range of 1:5 to 5:1, the neutron absorbing activity of the product may be controlled, which facilitates the manufacture of articles of particular absorbing activities best suitable for specific applications

  4. Corrosion resistant neutron absorbing coatings

    Science.gov (United States)

    Choi, Jor-Shan [El Cerrito, CA; Farmer, Joseph C [Tracy, CA; Lee, Chuck K [Hayward, CA; Walker, Jeffrey [Gaithersburg, MD; Russell, Paige [Las Vegas, NV; Kirkwood, Jon [Saint Leonard, MD; Yang, Nancy [Lafayette, CA; Champagne, Victor [Oxford, PA

    2012-05-29

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  5. 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)

  6. Burnable neutron absorbers

    International Nuclear Information System (INIS)

    Radford, K.C.; Carlson, W.G.

    1985-01-01

    This patent deals with the fabrication of pellets for neutron absorber rods. Such a pellet includes a matrix of a refractory material which may be aluminum or zirconium oxide, and a burnable poison distributed throughout the matrix. The neutron absorber material may consist of one or more elements or compounds of the metals boron, gadolinium, samarium, cadmium, europium, hafnium, dysprosium and indium. The method of fabricating pellets of these materials outlined in this patent is designed to produce pores or voids in the pellets that can be used to take up the expansion of the burnable poison and to absorb the helium gas generated. In the practice of this invention a slurry of Al 2 O 3 is produced. A hard binder is added and the slurry and binder are spray dried. This powder is mixed with dry B 4 C powder, forming a homogeneous mixture. This mixture is pressed into green tubes which are then sintered. During sintering the binder volatilizes leaving a ceramic with nearly spherical high-density regions of

  7. Heterogeneous neutron absorbers development

    International Nuclear Information System (INIS)

    Boccaccini, Aldo; Agueda, Horacio; Russo, Diego; Perez, Edmundo

    1987-01-01

    The use of solid burnable absorber materials in power light water reactors has increased in the last years, specially due to improvements attained in costs of generated electricity. The present work summarizes the basic studies made on an alumina-gadolinia system, where alumina is the inert matrix and gadolinia acts as burnable poison, and describes the fabrication method of pellets with that material. High density compacts were obtained in the range of concentrations used by cold pressing and sintering at 1600 deg C in inert (Ar) atmosphere. Finally, the results of the irradiation experiences made at RA-6 reactor, located at the Bariloche Atomic Center, are given where variations on negative reactivity caused by introduction of burnable poison rods were measured. The results obtained from these experiences are in good agreement with those coming from calculation codes. (Author)

  8. Neutron Absorbing Ability Variation in Neutron Absorbing Material Caused by the Neutron Irradiation in Spent Fuel Storage Facility

    International Nuclear Information System (INIS)

    Sohn, Hee Dong; Han, Seul Gi; Lee, Sang Dong; Kim, Ki Hong; Ryu, Eag Hyang; Park, Hwa Gyu

    2014-01-01

    In spent fuel storage facility like high density spent fuel storage racks and dry storage casks, spent fuels are stored with neutron absorbing materials installed as a part of those facilities, and they are used for absorbing neutrons emitted from spent fuels. Usually structural material with neutron absorbing material of racks and casks are located around spent fuels, so it is irradiated by neutrons for long time. Neutron absorbing ability could be changed by the variation of nuclide composition in neutron absorbing material caused by the irradiation of neutrons. So, neutron absorbing materials are continuously faced with spent fuels with boric acid solution or inert gas environment. Major nuclides in neutron absorbing material are Al 27 , C 12 , B 11 , B 10 and they are changed to numerous other ones as radioactive decay or neutron absorption reaction. The B 10 content in neutron absorbing material dominates the neutron absorbing ability, so, the variation of nuclide composition including the decrease of B 10 content is the critical factor on neutron absorbing ability. In this study, neutron flux in spent fuel, the activation of neutron absorbing material and the variation of nuclide composition are calculated. And, the minimum neutron flux causing the decrease of B 10 content is calculated in spent fuel storage facility. Finally, the variation of neutron multiplication factor is identified according to the one of B 10 content in neutron absorbing material. The minimum neutron flux to impact the neutron absorbing ability is 10 10 order, however, usual neutron flux from spent fuel is 10 8 order. Therefore, even though neutron absorbing material is irradiated for over 40 years, B 10 content is little decreased, so, initial neutron absorbing ability could be kept continuously

  9. Development of highly effective neutron shields and neutron absorbing materials

    International Nuclear Information System (INIS)

    Tsuda, K.; Matsuda, F.; Taniuchi, H.; Yuhara, T.; Iida, T.

    1993-01-01

    A wide range of materials, including polymers and hydrogen-occluded alloys that might be usable as the neutron shielding material were examined. And a wide range of materials, including aluminum alloys that might be usable as the neutron-absorbing material were examined. After screening, the candidate material was determined on the basis of evaluation regarding its adaptabilities as a high-performance neutron-shielding and neutron-absorbing material. This candidate material was manufactured for trial, after which material properties tests, neutron-shielding tests and neutron-absorbing tests were carried out on it. The specifications of this material were thus determined. This research has resulted in materials of good performance; a neutron-shielding material based on ethylene propylene rubber and titanium hydride, and a neutron-absorbing material based on aluminum and titanium hydride. (author)

  10. Neutron absorbers and methods of forming at least a portion of a neutron absorber

    Science.gov (United States)

    Guillen, Donna P; Porter, Douglas L; Swank, W David; Erickson, Arnold W

    2014-12-02

    Methods of forming at least a portion of a neutron absorber include combining a first material and a second material to form a compound, reducing the compound into a plurality of particles, mixing the plurality of particles with a third material, and pressing the mixture of the plurality of particles and the third material. One or more components of neutron absorbers may be formed by such methods. Neutron absorbers may include a composite material including an intermetallic compound comprising hafnium aluminide and a matrix material comprising pure aluminum.

  11. Neutron absorbed dose in a pacemaker CMOS

    Energy Technology Data Exchange (ETDEWEB)

    Borja H, C. G.; Guzman G, K. A.; Valero L, C. Y.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L., E-mail: candy_borja@hotmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2011-11-15

    The absorbed dose due to neutrons by a Complementary Metal Oxide Semiconductor (CMOS) has been estimated using Monte Carlo methods. Eventually a person with a pacemaker becomes a patient that must be treated by radiotherapy with a linear accelerator; the pacemaker has integrated circuits as CMOS that are sensitive to intense and pulsed radiation fields. When the Linac is working in Bremsstrahlung mode an undesirable neutron field is produced due to photoneutron reactions; these neutrons could damage the CMOS putting the patient at risk during the radiotherapy treatment. In order to estimate the neutron dose in the CMOS a Monte Carlo calculation was carried out where a full radiotherapy vault room was modeled with a W-made spherical shell in whose center was located the source term of photoneutrons produced by a Linac head operating in Bremsstrahlung mode at 18 MV. In the calculations a phantom made of tissue equivalent was modeled while a beam of photoneutrons was applied on the phantom prostatic region using a field of 10 x 10 cm{sup 2}. During simulation neutrons were isotropically transported from the Linac head to the phantom chest, here a 1 {theta} x 1 cm{sup 2} cylinder made of polystyrene was modeled as the CMOS, where the neutron spectrum and the absorbed dose were estimated. Main damages to CMOS are by protons produced during neutron collisions protective cover made of H-rich materials, here the neutron spectrum that reach the CMOS was calculated showing a small peak around 0.1 MeV and a larger peak in the thermal region, both connected through epithermal neutrons. (Author)

  12. Neutron visual sensing technique

    International Nuclear Information System (INIS)

    Kureta, Masatoshi; Segawa, Mariko

    2014-01-01

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

  13. Method of manufacturing improved neutron absorbers

    International Nuclear Information System (INIS)

    Ito, Masahiko; Yuzuhara, Shun-ichi; Tamaki, Shohei.

    1987-01-01

    Purpose: To obtain control rods capable of suppressing swelling and having increased working life, high safety and economical advantage. Method: Boron carbide sintered body as the neutron absorber is adjusted such that the boron/carbon atomic ratio is within a range of 4.0 ± 0.2 and the average crystal grain size is of less than 5 μm. Then, for suppressing the growing of crystal grains in the course of sintering, press-sintering is applied under the conditions of a temperature at 1700 - 2200 deg C and a pressure of 100 - 500 kg/cm 2 . Aimed control rods can thus be obtained. If the average crystal grain size exceeds 5 μm, the diffusion rate of He formed by the neutron absorption reaction is fast at the grain boundary, whereas it is relatively low within the crystal grains. Accordingly, the He possessing amount is increased and the swelling is increased in the case of such large grain size that the grain boundary area per unit volume is relatively small. (Takahashi, M.)

  14. Neutron detection technique

    CERN Document Server

    Oblath, N S

    2000-01-01

    The Sudbury Neutrino Observatory (SNO) has the ability to measure the total flux of all active flavors of neutrinos using the neutral current reaction, whose signature is a neutron. By comparing the rates of the neutral current reaction to the charged current reaction, which only detects electron neutrinos, one can test the neutrino oscillation hypothesis independent of solar models. It is necessary to understand the neutron detection efficiency of the detector to make use of the neutral current reaction. This report demonstrates a coincidence technique to identify neutrons emitted from the sup 2 sup 5 sup 2 Cf neutron calibration source. The source releases on average four neutrons when a sup 2 sup 5 sup 2 Cf nucleus spontaneously fissions. Each neutron is detected as a separate event when the neutron is captured by a deuteron, releasing a gamma ray of approximately 6.25 MeV. This gamma ray is in turn detected by the photomultiplier tube (PMT) array. By investigating the time and spatial separation between n...

  15. Neutron absorbing room temperature vulcanizable silicone rubber compositions

    International Nuclear Information System (INIS)

    Zoch, H.L.

    1979-01-01

    A neutron absorbing composition is described and consists of a one-component room temperature vulcanizable silicone rubber composition or a two-component room temperature vulcanizable silicone rubber composition in which the composition contains from 25 to 300 parts by weight based on the base silanol or vinyl containing diorganopolysiloxane polymer of a boron compound or boron powder as the neutron absorbing ingredient. An especially useful boron compound in this application is boron carbide. 20 claims

  16. Neutron absorbing article and method for manufacture of such article

    International Nuclear Information System (INIS)

    Hortman, M.T.; Mcmurtry, C.H.; Naum, R.G.; Owens, D.P.

    1980-01-01

    A neutron absorbing article, preferably in long, thin, flat form , suitable for but not necessarily limited to use in storage racks for spent nuclear fuel at locations between volumes of such stored fuel, to absorb neutrons from said spent fuel and prevent uncontrolled nuclear reaction of the spent fuel material, is composed of finely divided boron carbide particles and a solid, irreversibly cured phenolic polymer, forming a continuous matrix about the boron carbide particles, in such proportions that at least 6% of b10 from the boron carbide content is present therein. The described articles withstand thermal cycling from repeated spent fuel insertions and removals, withstand radiation from said spent nuclear fuel over long periods of time without losing desirable neutron absorbing and physical properties, are sufficiently chemically inert to water so as to retain neutron absorbing properties if brought into contact with it, are not galvanically corrodible and are sufficiently flexible so as to withstand operational basis earthquake and safe shutdown earthquake seismic events, without loss of neutron absorbing capability and other desirable properties, when installed in storage racks for spent nuclear fuel. The disclosure also relates to a plurality of such neutron absorbing articles in a storage rack for spent nuclear fuel and to a method for the manufacture of the articles

  17. 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

  18. Technology and assessment of neutron absorbing materials

    International Nuclear Information System (INIS)

    Kelly, B.T.; Murgatroyd, R.A.

    1977-06-01

    The present review assesses more recent developments in the technology and application of those absorber materials which are considered to be established or to have shown potential in reactor control. Emphasis is placed on physical, chemical and metallurgical properties and upon irradiation behaviour. (author)

  19. Neutron radiography, techniques and applications

    International Nuclear Information System (INIS)

    Domanus, J.C.

    1987-10-01

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

  20. Integrity of neutron-absorbing components of LWR fuel systems

    International Nuclear Information System (INIS)

    Bailey, W.J.; Berting, F.M.

    1991-03-01

    A study of the integrity and behavior of neutron-absorbing components of light-water (LWR) fuel systems was performed by Pacific Northwest Laboratory (PNL) and sponsored by the US Department of Energy (DOE). The components studies include control blades (cruciforms) for boiling-water reactors (BWRs) and rod cluster control assemblies for pressurized-water reactors (PWRs). The results of this study can be useful for understanding the degradation of neutron-absorbing components and for waste management planning and repository design. The report includes examples of the types of degradation, damage, or failures that have been encountered. Conclusions and recommendations are listed. 84 refs

  1. Neutron absorbing materials for reactors control; Materiaux absorbants neutroniques pour le pilotage des reacteurs

    Energy Technology Data Exchange (ETDEWEB)

    Gosset, D. [CEA Saclay, Dept. des Materiaux pour le Nucleaire (DMN), 91 - Gif sur Yvette (France); Herter, P. [CEA Saclay, Dir. de l' Energie Nucleaire (DEN), 91 - Gif sur Yvette (France)

    2007-01-15

    The different reactivity control systems allow to keep the mastery of the fission reaction inside the reactor core at any time: power control, safe shutdown, compensation of fuel burnup. These systems can be of different type: gaseous (like {sup 3}He in some experimental reactors), liquid (borated water in PWRs), and in most cases solid and combined or not with the previous types. In all cases, the constituents comprise neutron absorbing nuclides. The absorbing materials are contained in elementary absorbing elements, named control rods. This article describes the absorbing materials used in the control rods of the main nuclear power plants and also in the burnable poison rods of water cooled reactors. Content: 1 - general considerations about absorbing materials: neutron absorption cross sections, selection criteria of absorbing materials, main uses of absorbers in reactors, supply sources, wastes; 2 - description of the absorbing materials used: silver-indium-cadmium alloy (ICA), boron carbide (B{sub 4}C), dysprosium titanate, hafnium, burnable poisons and rare earths; 3 - conclusion and perspectives. (J.S.)

  2. New techniques in neutron scattering

    International Nuclear Information System (INIS)

    Hayter, J.B.

    1993-01-01

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

  3. A transformation technique to treat strong vibrating absorbers

    International Nuclear Information System (INIS)

    Sahni, D.C.; Garis, N.S.; Pazsit, I.

    1998-06-01

    Calculation of the neutron noise, induced by small amplitude vibrations of a strong absorber, is a difficult task because the traditional linearization technique cannot be applied. Two methods, based on two different representations of the absorber, were developed earlier to solve the problem. In both methods the rod displacements are described by a Taylor expansion, such that the boundary condition needs only to be considered at the surface of a static rod. Only one of the methods is applicable in two dimensions. In this paper an alternative method is developed and used for the solution of the problem. The essence of the method is a variable transformation by which the moving boundary is transformed into a static one without Taylor expansion. The corresponding equations are solved in a linear manner and the solution is transformed back to the original parameter space. The method is equally applicable in one and two dimensions. The solutions are in complete agreement with those of the previous methods

  4. Neutron absorber qualification and acceptance testing from the designer's perspective

    International Nuclear Information System (INIS)

    Bracey, W.; Chiocca, R.

    2004-01-01

    Starting in the mid 1990's, the USNRC began to require less than 100% credit for the 10B present in fixed neutron absorbers spent fuel transport packages. The current practice in the US is to use only 75% of the specified 10B in criticality safety calculations unless extensive acceptance testing demonstrates both the presence of the 10B and uniformity of its distribution. In practice, the NRC has accepted no more than 90% credit for 10B in recent years, while other national competent authorities continue to accept 100%. More recently, with the introduction of new neutron absorber materials, particularly aluminum / boron carbide metal matrix composites, the NRC has also expressed expectations for qualification testing, based in large part on Transnuclear's successful application to use a new composite material in the TN-68 storage / transport cask. The difficulty is that adding more boron than is really necessary to a metal has some negative effects on the material, reducing the ductility and the thermal conductivity, and increasing the cost. Excessive testing requirements can have the undesired effect of keeping superior materials out of spent fuel package designs, without a corresponding justification based on public safety. In European countries and especially in France, 100% credit has been accepted up to now with materials controls specified in the Safety Analysis Report (SAR): Manufacturing process approved by qualification testing Materials manufacturing controlled under a Quality Assurance system. During fabrication, acceptance testing directly on products or on representative samples. Acceptance criteria taking into account a statistical uncertainty corresponding to 3σ. The original and current bases for the reduced 10 B credit, the design requirements for neutron absorber materials, and the experience of Transnuclear and Cogema Logistics with neutron absorber testing are examined. Guidelines for qualification and acceptance testing and process controls

  5. Experimental technique of neutron reflection

    International Nuclear Information System (INIS)

    Chen Bo; Huang Chaoqiang; Li Xinxi

    2006-12-01

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

  6. Neutron absorbing article and method for manufacture thereof

    International Nuclear Information System (INIS)

    Forsyth, P.F.; Mcmurtry, C.H.; Naum, R.G.

    1980-01-01

    A composite, neutron absorbing, coated article, suitable for installation in storage racks for spent nuclear fuel and for other neutron absorbing applications, includes a backing member, preferably of flexible material such as woven fiberglass cloth, a synthetic organic polymeric coating or a plurality of such coatings on the backing member, preferably of cured phenolic resin, such as phenol formaldehyde or trimethylolphenol formaldehyde and boron carbide particles held to the backing member by the cured coating or a plurality of such coatings. Also within the invention is a method for the manufacture of the neutron absorbing coated article and the use of such an article. In a preferred method the backing member is first coated on both sides thereof with a filling coating of thermosettable liquid phenolic resin, which is then partially cured to solid state, one side of the backing member is then coated with a mixture of thermosettable liquid resin and finely divided boron carbide particles and the resin is partially cured to solid state, the other side is coated with a similar mixture, larger boron carbide particles are applied to it and the resin is partially cured to solid state, such side of the article is coated with thermosettable liquid phenolic resin, the resin is partially cured to solid state and such resin, including previously applied partially cured resins, is cured to final cross-linked and permanently set form

  7. Study of neutron absorbing microspheres in research reactors - Neutronic analyse

    International Nuclear Information System (INIS)

    Gana Watkins, Ignacio A.; Prado, Miguel O.; Mazufri, Claudio; Tunon, Juan M

    2012-01-01

    Now-a-days, it is increasingly common for nuclear power plants, as well as research reactors, to be designed and built with an alternative safety system aside from control rods. The acids and/or salts in solution injection systems is most frequently used. However, these systems present several implementation and operation problems due to the physical and chemical properties of the used compounds. After analyzing these drawbacks, we developed a new alternative safety system that contains the absorbing element isolated from the aqueous medium. In this context, it's proposed the use of aluminum borosilicate microspheres. The current paper presents erosion wear experiments to determine under which conditions microspheres can be considered as a potential component of a secondary shut down system in a nuclear facility (author)

  8. Characterization of weak, fair and strong neutron absorbing materials by means of neutron transmission: Beam hardening effect

    International Nuclear Information System (INIS)

    Kharfi, F.; Bastuerk, M.; Boucenna, A.

    2006-01-01

    The characterization of neutron absorbing materials as well as quantification of neutron attenuation through matter is very essential in various fields, namely in shielding calculation. The objective of this work is to describe an experimental procedure to be used for the determination of neutron transmission through different materials. The proposed method is based on the relation between the gray value measured on neutron radiography image and the corresponding inducing neutron beam. For such a purpose, three kinds of materials (in shape of plate) were investigated using thermal neutrons: (1) boron-alloyed stainless steel as strong absorber; (2) copper and steel as fair absorbers and (3) aluminum as weak absorber. This work is not limited to the determination of neutron transmission through matters; it is also spread out to the measure of the surface density of the neutron absorbing elements (ρ s ) as a function of thickness of neutron absorbing material such as boron-alloyed stainless steel. The beam hardening effect depending on material thickness was also studied using the neutron transmission measurements. A theoretical approach was used to interpret the experimental results. The neutron transmission measurements were performed at the Neutron Radiography and Tomography facility of the Atomic Institute of the Austrian Universities in Vienna. Finally, a Maxwellian neutron distribution of incident neutron beam was used in the theoretical calculations of neutron energy shift in order to compare with experiments results. The obtained experimental results are in a good agreement with the developed theoretical approach

  9. Characterization of weak, fair and strong neutron absorbing materials by means of neutron transmission: Beam hardening effect

    Science.gov (United States)

    Kharfi, F.; Bastuerk, M.; Boucenna, A.

    2006-09-01

    The characterization of neutron absorbing materials as well as quantification of neutron attenuation through matter is very essential in various fields, namely in shielding calculation. The objective of this work is to describe an experimental procedure to be used for the determination of neutron transmission through different materials. The proposed method is based on the relation between the gray value measured on neutron radiography image and the corresponding inducing neutron beam. For such a purpose, three kinds of materials (in shape of plate) were investigated using thermal neutrons: (1) boron-alloyed stainless steel as strong absorber; (2) copper and steel as fair absorbers and (3) aluminum as weak absorber. This work is not limited to the determination of neutron transmission through matters; it is also spread out to the measure of the surface density of the neutron absorbing elements (ρs) as a function of thickness of neutron absorbing material such as boron-alloyed stainless steel. The beam hardening effect depending on material thickness was also studied using the neutron transmission measurements. A theoretical approach was used to interpret the experimental results. The neutron transmission measurements were performed at the Neutron Radiography and Tomography facility of the Atomic Institute of the Austrian Universities in Vienna. Finally, a Maxwellian neutron distribution of incident neutron beam was used in the theoretical calculations of neutron energy shift in order to compare with experiments results. The obtained experimental results are in a good agreement with the developed theoretical approach.

  10. New Techniques in Neutron Scattering

    DEFF Research Database (Denmark)

    Birk, Jonas Okkels

    potential performance than any existing facility, however in order to use this pulse structure optimally many existing neutron scattering instruments will need to be redesigned. This defense will concentrate on the design and optimization of the inverse time-of-flight cold neutron spectrometer CAMEA......, simulations and prototyping to optimize the instrument and ensure that it will deliver the predicted performance when constructed. During the design a new prismatic analyser concept that can be of interest to many other neutron spectrometers was developed. The design work was compiled into an instrument......Neutron scattering is an important experimental technique in amongst others solid state physics, biophysics, and engineering. This year construction of European Spallation Source (ESS) was commenced in Lund, Sweeden. The facility will use a new long pulsed source principle to obtain higher...

  11. Integral neutron transport theory, slowing-down theory for absorber lump in an isotropic neutron bath

    International Nuclear Information System (INIS)

    Tai, D.; Underhill, G.K.

    1975-01-01

    The Boltzmann integrodifferential neutron transport equation has been converted to an integral equation which incorporates the isotropic neutron bath boundary condition. The resulting integral equation is solved using the discrete ordinates method, resulting in solutions for the spatially-dependent and -independent fluxes in terms of transport probabilities and the neutron emission density. The transport probabilities and the lethargy-dependence solution are evaluated using a normalization condition and a neutron conservation equation, respectively, to correct for inherent error propagation. The formalism is applied to the calculation of uranium resonance integrals for a spherical, two-region lump consisting of a spherical absorber surrounded by a spherical cadmium cover. Calculated and experimental results for uranium-235 fission and uranium-238 capture resonance integrals compare favorably. 11 references. (U.S.)

  12. Pulsed neutron generator for use with pulsed neutron activation techniques

    International Nuclear Information System (INIS)

    Rochau, G.E.

    1980-01-01

    A high-output, transportable, pulsed neutron generator has been developed by Sandia National Laboratories for use with Pulsed Neutron Activation (PNA) techniques. The PNA neutron generator generates > 10 10 14 MeV D-T neutrons in a 1.2 millisecond pulse. Each operation of the unit will produce a nominal total neutron output of 1.2 x 10 10 neutrons. The generator has been designed to be easily repaired and modified. The unit requires no additional equipment for operation or measurement of output

  13. Genetic effects induced by neutrons in Drosophila melanogaster I. Determination of absorbed dose

    International Nuclear Information System (INIS)

    Delfin, A.; Paredes, L.C.; Zambrano, F.; Guzman-Rincon, J.; Urena-Nunez, F.

    2001-01-01

    A method to obtain the absorbed dose in Drosophila melanogaster irradiated in the thermal column facility of the Triga Mark III Reactor has been developed. The method is based on the measurements of neutron activation of gold foils produced by neutron capture to obtain the neutron fluxes. These fluxes, combined with the calculations of kinetic energy released per unit mass, enables one to obtain the absorbed doses in Drosophila melanogaster

  14. Radiolysis of some aqueous solutions of neutron absorbers

    International Nuclear Information System (INIS)

    Rozenberg, J.

    1964-12-01

    The initial yield of molecular hydrogen formed by radiolytic decomposition of water in reactor and 60 Co gamma radiation is decreased by the presence of salts of polyvalent elements possessing only one stable valence, i.e cadmium, zinc, magnesium, gadolinium. This effect is favourable for the use of cadmium and gadolinium as soluble neutron absorber in heavy water reactors. Cations of these salts are not inert toward the primary products of water radiolysis. They have a high degree of reactivity toward the hydrated electron, which is the precursor of molecular hydrogen in neutral or alkaline aqueous media. The value of the rate constant for the reaction between cadmium ion and hydrated electron was shown to be (6.1 ± 1.8) 10 10 M -1 s -1 . Boric acid at low concentration has no effect on the radiation chemistry of water. An isotope effect has been found in the radiolysis of heavy water, corresponding to a lowering of initial yield [G 0 (D 2 ) 0 (H 2 )]. additionally it was necessary to determine the influence of organic impurities, remaining after the purification of water, on the mechanism of its radiolytic decomposition. (author) [fr

  15. DNA Infrared Absorbency Detection using Photopyroelectric Technique and FTIR Spectroscopy

    OpenAIRE

    Ebu-TEİR, Musa; Abu-TAHA, Mohammad; Al-JAMAL, Atef; EİDEH, H.

    2008-01-01

    Absorbencies of different DNA samples were studied using the well known photopyroelectric (PPE) technique and Fourier Transform Infrared (FTIR) spectrometer. In the fi rst method, wideband radiation absorbance from an infrared (IR) pulsed wideband source (PWBS) by DNA samples were detected and compared with FTIR spectrum. It was shown that the PPE technique results are useful and comparable to FTIR in distinguishing different DNA samples of biological interests

  16. Boron cage compound materials and composites for shielding and absorbing neutrons

    Science.gov (United States)

    Bowen, III, Daniel E; Eastwood, Eric A

    2014-03-04

    Boron cage compound-containing materials for shielding and absorbing neutrons. The materials include BCC-containing composites and compounds. BCC-containing compounds comprise a host polymer and a BCC attached thereto. BCC-containing composites comprise a mixture of a polymer matrix and a BCC filler. The BCC-containing materials can be used to form numerous articles of manufacture for shielding and absorbing neutrons.

  17. Neutron relative biological effectiveness for solid cancer incidence in the Japanese A-bomb survivors: an analysis considering the degree of independent effects from γ-ray and neutron absorbed doses with hierarchical partitioning.

    Science.gov (United States)

    Walsh, Linda

    2013-03-01

    It has generally been assumed that the neutron and γ-ray absorbed doses in the data from the life span study (LSS) of the Japanese A-bomb survivors are too highly correlated for an independent separation of the all solid cancer risks due to neutrons and due to γ-rays. However, with the release of the most recent data for all solid cancer incidence and the increased statistical power over previous datasets, it is instructive to consider alternatives to the usual approaches. Simple excess relative risk (ERR) models for radiation-induced solid cancer incidence fitted to the LSS epidemiological data have been applied with neutron and γ-ray absorbed doses as separate explanatory covariables. A simple evaluation of the degree of independent effects from γ-ray and neutron absorbed doses on the all solid cancer risk with the hierarchical partitioning (HP) technique is presented here. The degree of multi-collinearity between the γ-ray and neutron absorbed doses has also been considered. The results show that, whereas the partial correlation between the neutron and γ-ray colon absorbed doses may be considered to be high at 0.74, this value is just below the level beyond which remedial action, such as adding the doses together, is usually recommended. The resulting variance inflation factor is 2.2. Applying HP indicates that just under half of the drop in deviance resulting from adding the γ-ray and neutron absorbed doses to the baseline risk model comes from the joint effects of the neutrons and γ-rays-leaving a substantial proportion of this deviance drop accounted for by individual effects of the neutrons and γ-rays. The average ERR/Gy γ-ray absorbed dose and the ERR/Gy neutron absorbed dose that have been obtained here directly for the first time, agree well with previous indirect estimates. The average relative biological effectiveness (RBE) of neutrons relative to γ-rays, calculated directly from fit parameters to the all solid cancer ERR model with both

  18. Techniques Closely Related to Pulsed Neutron Research

    International Nuclear Information System (INIS)

    Uhrig, R.E.

    1965-01-01

    Techniques related to pulsed neutron research involve the injection of neutrons at one of the boundaries of a nuclear system, and the localized perturbation of the neutron population then propagates throughout the system. The disturbance introduced at the boundary may be continuous, such as a sinusoidal modulation (neutron wave technique) or a pseudo-random (on-off) variation of source strength (pseudo-random pulsing), or it may be a single burst of neutrons. Propagation of the perturbation can be dealt with as a spatially dependent pulse propagation problem. Hence, the impulse response (and source transfer function) of the system at any point can be determined from neutron wave or pseudo-random pulsing experiments which, in turn, allow the evaluation of the nuclear parameters of the system. The neutron wave technique is used to measure diffusion parameters of moderators, the nuclear properties of subcritical assemblies, and to measure thermalization power and diffusion cooling in crystalline moderators. The pseudo-random pulsing technique was developed as a means of measuring subcriticality of nuclear systems. Cross-correlation of the input with the neutron density at several points throughout the system yields the spatially dependent impulse response of the system which can be Fourier-transformed to yield a dispersion (or transfer) function. Other phenomena, including reflection of neutron waves from the interface between heavy water and graphite, interference between propagating disturbances and the lattice of a heavy water, natural uranium system, and neutron pulse propagation in graphite using a pulsed TRIGA reactor as an intense neutron source have been demonstrated. Recent trends in data reduction are toward the incorporation of ''on-line'' digital computers for data reduction. Such techniques, now used for pulse height analysis, are being developed for multichannel time analysis for all types of pulsed neutron research. Data analysis often involves

  19. Influence of an absorbing sublayer on polarizing property of magnetic neutron mirrors

    International Nuclear Information System (INIS)

    Korneev, D.A.; Pasyuk, V.V.; Petrenko, A.V.

    1991-01-01

    Measurements of the neutron reflectivity profile from absorbing thin film mirrors deposited onto glass substrates are presented and the results compared with theoretical predictions. The spectral dependence of the scattering length of natural Gd and GdTi alloy has been determined for the first time for the thermal neutron energy range. The unstable behavior of the neutron scattering length of Gd and consequently the principle impossibility of its compensation in a wide interval of neutron wavelengths is the reason of the strong decreasing of the polarizing properties of neutron guides with ferromagnetic mirrors. The possibility is discussed of producing a new absorbing sublayers with an important decrease of reflection in the neutron wavelength range from 1 to 10 A. The neutron reflectivity was analyzed for absorbing thin BTi, BV and CdV alloys on glass substrates. The calculated reflectivity as a function of neutron wavelength was optimized for concentration and layer thickness. Fist experimental data have been performed at the Laboratory of Neutron Physics (Joint Institute for Nuclear Research, Dubna) and are presented. (author). 7 refs, 7 figs

  20. Mitigation of end flux peaking in CANDU fuel bundles using neutron absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Pierce, D.; Chan, P.K., E-mail: dylan.pierce@rmc.ca [Royal Military College of Canada, Kingston ON, (Canada); Shen, W. [Canadian Nuclear Safety Commission, Ottawa ON, (Canada)

    2015-07-01

    End flux peaking (EFP) is a phenomenon where a region of elevated neutron flux occurs between two adjoining fuel bundles. These peaks lead to an increase in fission rate and therefore greater heat generation. It is known that addition of neutron absorbers into fuel bundles can help mitigate EFP, yet implementation in Canada Deuterium Uranium (CANDU) type reactors using natural uranium fuel has not been pursued. Monte Carlo N-Particle code (MCNP) 6.1 was used to simulate the addition of a small amount of neutron absorbers strategically within the fuel pellets. This paper will present some preliminary results collected thus far. (author)

  1. Neutron flux measurement utilizing Campbell technique

    International Nuclear Information System (INIS)

    Kropik, M.

    2000-01-01

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

  2. Two detector pulse neutron logging porosity technique

    International Nuclear Information System (INIS)

    Schwartz, R.J.

    1971-01-01

    An illustrative embodiment of the invention discloses a technique for reducing the influence of borehole characteristics on earth formation porosity measurements. Measurements of this sort are accomplished with a borehole logging tool and comprises two neutron detectors spaced at different distances from a pulsed neutron generator. The thermal neutron decay time of the short-spaced detector identifies that portion of the time-dependent population that is most indicative of the formation porosity. Both detectors then register the portion of the neutron distribution so identified to produce two signals from which a ratio is computed that is related to the porosity of the formation. (auth)

  3. Neutron borehole logging correction technique

    International Nuclear Information System (INIS)

    Goldman, L.H.

    1978-01-01

    In accordance with an illustrative embodiment of the present invention, a method and apparatus is disclosed for logging earth formations traversed by a borehole in which an earth formation is irradiated with neutrons and gamma radiation produced thereby in the formation and in the borehole is detected. A sleeve or shield for capturing neutrons from the borehole and producing gamma radiation characteristic of that capture is provided to give an indication of the contribution of borehole capture events to the total detected gamma radiation. It is then possible to correct from those borehole effects the total detected gamma radiation and any earth formation parameters determined therefrom

  4. Determination of hydrogen content by neutron techniques

    International Nuclear Information System (INIS)

    Santisteban, J.R.; Granada, J.R.; Mayer, R.E.

    1997-01-01

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

  5. Role of cytogenetic techniques in biological dosimetry of absorbed radiation

    International Nuclear Information System (INIS)

    Rao, B.S.

    2016-01-01

    In most of the radiation accidents, physical dosimetric information is rarely available. Further, most of the accidental exposures are non-uniform involving either partial body or localized exposure to significant doses. In such situations, physical dosimetry does not provide reliable dose estimate. It has now been realized that biological dosimetric techniques can play an important role in the assessment of absorbed dose. In recent years, a number of biological indicators of radiation have been identified. These include the kinetics of onset and persistence of prodromal syndromes (radiation sickness), cytogenetic changes in peripheral blood lymphocytes, hematological changes, biochemical indicators, ESR spectroscopy of biological samples, induction of gene mutations in red blood cells, cytogenetic and physiological changes in skin and neurophysiological changes. In general, dosimetric information is derived by a combination of several different methods, as they have potential to serve as prognostic indicators. The role of cytogenetic techniques in peripheral blood lymphocytes (PBL) as biological indicators of absorbed radiation is reviewed here

  6. Neutron diffusion in graphite poisoned with 1/v and non-1/v absorbers

    International Nuclear Information System (INIS)

    Malik, U.; Kothari, L.S.; Kumar, A.

    1982-01-01

    Neutron diffusion in graphite containing 1/v and non-1/v absorbers has been studied in the diffusion theory approximation using a multigroup (30-group) approach and the neutron scattering kernel proposed earlier by the authors. It is observed that, in this case as in the case of water investigated earlier, the behavior of neutrons in graphite poisoned with gadolinium is different from that in graphite poisoned with samarium or cadmium. To explain the reason for this difference, a hypothetical model for the energy variation of the absorption cross section has been constructed that closely resembles samarium in one limit and goes over to gadolinium in the other. The effect of varying the concentration of non-1/v absorbers on the flux of sub-Bragg and epicold neutrons has been studied for this model, and some interesting results are obtained

  7. Secondary neutron dose measurement for proton eye treatment using an eye snout with a borated neutron absorber

    Science.gov (United States)

    2013-01-01

    Background We measured and assessed ways to reduce the secondary neutron dose from a system for proton eye treatment. Methods Proton beams of 60.30 MeV were delivered through an eye-treatment snout in passive scattering mode. Allyl diglycol carbonate (CR-39) etch detectors were used to measure the neutron dose in the external field at 0.00, 1.64, and 6.00 cm depths in a water phantom. Secondary neutron doses were measured and compared between those with and without a high-hydrogen–boron-containing block. In addition, the neutron energy and vertices distribution were obtained by using a Geant4 Monte Carlo simulation. Results The ratio of the maximum neutron dose equivalent to the proton absorbed dose (H(10)/D) at 2.00 cm from the beam field edge was 8.79 ± 1.28 mSv/Gy. The ratio of the neutron dose equivalent to the proton absorbed dose with and without a high hydrogen-boron containing block was 0.63 ± 0.06 to 1.15 ± 0.13 mSv/Gy at 2.00 cm from the edge of the field at depths of 0.00, 1.64, and 6.00 cm. Conclusions We found that the out-of-field secondary neutron dose in proton eye treatment with an eye snout is relatively small, and it can be further reduced by installing a borated neutron absorbing material. PMID:23866307

  8. Modelling of neutron absorbers in high temperature reactors by combined transport diffusion methods

    OpenAIRE

    Fen, V.; Lebedev, M.; Sarytchev, V.; Scherer, W.

    1992-01-01

    Today, the neutron-physical description of strong neutron absorbing materials for control and shut-down of nuclear power plants is performed using combined transport and diffusion methods. Two of these approaches are described and compared in this paper. The method of equivalent cross-sections has been developed at the KFA-Jülich Institute for Safety Research and Reactor Technology (ISR) and was widely used for all german HTR reactor concepts. The Obninsk Institute for Nuclear Power Engineeri...

  9. Degradation analysis of neutrons absorber bars Ag-In-Cd. Part 1: alloy depletion, neutrons absorption effectiveness and mechanical properties

    International Nuclear Information System (INIS)

    Castanheira, Myrthes; Terremoto, Luis Antonio A.; Silva, Jose Eduardo Rosa da; Zeituni, Carlos Alberto

    2002-01-01

    The original alloy of IEA-R1 reactor absorber bars (supposing similar to alloy 2533 with composition 81,5% Ag - 136% In -4,9% Cd) was designed to work for a life time equivalent to a neutron exposition of ∼10 21 n/cm 2 (thermal) so that the alloy can preserve the characteristic one phase. Analyzing the behavior of absorber bars Ag-In-Cd under irradiation, this work reports a semi quantitative assessment of the IEA-R1 absorber bars degradation current condition by viewpoint of alloy depletion, neutrons absorption effectiveness and mechanical properties, as a complement of visual inspections results carried out at 1998, 2000 and 2001 whose had pointed to visible degree of degradation accumulated along 29 years of operation in the reactor. (author)

  10. Techniques in high pressure neutron scattering

    CERN Document Server

    Klotz, Stefan

    2013-01-01

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

  11. Conventional high pressure techniques fro neutron diffraction

    International Nuclear Information System (INIS)

    Mizuki, Jun-ichiro; Endoh, Yasuo

    1981-01-01

    Conventional high pressure techniques using a clamped type pressure cell have been adapted for studies by neutron diffraction. Careful calibration of the pressure sensing apparatus and an appropriate choice of pressure transmitting medium enable accurate neutron diffraction measurements to be made at reduced temperature as low as 4 K. In the present studies we have demonstrated that using the clamped type microbomb neutron diffraction measurements can be easily made under the pressure up to 5 kbar within the temperature range 4 K - 350 K. (author)

  12. Neutron Scattering in Biology Techniques and Applications

    CERN Document Server

    Fitter, Jörg; Katsaras, John

    2006-01-01

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

  13. Carbon filter property detection with thermal neutron technique

    International Nuclear Information System (INIS)

    Deng Zhongbo; Han Jun; Li Wenjie

    2003-01-01

    The paper discussed the mechanism that the antigas property of the carbon filter will decrease because of its carbon bed absorbing water from the air while the carbon filter is being stored, and introduced the principle and method of detection the amount of water absorption with thermal neutron technique. Because some certain relation between the antigas property of the carbon filter and the amount of water absorption exists, the decrease degree of the carbon filter antigas property can be estimated through the amount of water absorption, offering a practicable facility technical pathway to quickly non-destructively detect the carbon filter antigas property

  14. An absorbable thread suture technique to treat snoring.

    Science.gov (United States)

    Kwon, Jang-Woo; Kong, Tae-Hoon; Ha, Tae-Hyoung; Park, Dong-Joon

    2016-05-01

    We investigated a novel, minimally invasive surgery that uses an absorbable suture technique to treat snoring and mild obstructive sleep apnea. This simple procedure was developed to increase the stiffness of the soft palate and to promote uvula elevation with sutures. Thirty-five snorer and mild obstructive sleep apnea syndrome patients were included in this study. The palate was sutured with the newly developed technique. The results of our surgery were evaluated using polysomnography (PSG), the Epworth sleepiness scale (ESS), and a visual analogue scale (VAS) before surgery and 90 days after surgery. One year after surgery, telephone interviews were performed to assess patient satisfaction. Postoperative physical examinations of all patients showed increased stiffness of the soft palate and superiorly displaced uvula. These findings were consistent after the postoperative day 90. The patients' snoring symptoms and their bed partners' complaints, assessed by ESS and VAS, significantly improved compared to the pre-treatment value (p snoring and mild obstructive sleep apnea.

  15. Applications of neutron activation analysis technique

    International Nuclear Information System (INIS)

    Jonah, S. A.

    2000-07-01

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

  16. Neutron radiographic techniques, facilities and applications

    International Nuclear Information System (INIS)

    Domanus, J.C.

    1984-08-01

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

  17. Integrating techniques for neutron dosimetry in Linac 18 MV

    International Nuclear Information System (INIS)

    Ceron R, P. V.; Diaz G, J. A. I.; Rivera M, T.; Paredes G, L. C.; Vega C, H. R.

    2015-10-01

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

  18. Critical experiments on an enriched uranium solution system containing periodically distributed strong thermal neutron absorbers

    International Nuclear Information System (INIS)

    Rothe, R.E.

    1996-01-01

    A series of 62 critical and critical approach experiments were performed to evaluate a possible novel means of storing large volumes of fissile solution in a critically safe configuration. This study is intended to increase safety and economy through use of such a system in commercial plants which handle fissionable materials in liquid form. The fissile solution's concentration may equal or slightly exceed the minimum-critical-volume concentration; and experiments were performed for high-enriched uranium solution. Results should be generally applicable in a wide variety of plant situations. The method is called the 'Poisoned Tube Tank' because strong neutron absorbers (neutron poisons) are placed inside periodically spaced stainless steel tubes which separate absorber material from solution, keeping the former free of contamination. Eight absorbers are investigated. Both square and triangular pitched lattice patterns are studied. Ancillary topics which closely model typical plant situations are also reported. They include the effect of removing small bundles of absorbers as might occur during inspections in a production plant. Not taking the tank out of service for these inspections would be an economic advantage. Another ancillary topic studies the effect of the presence of a significant volume of unpoisoned solution close to the Poisoned Tube Tank on the critical height. A summary of the experimental findings is that boron compounds were excellent absorbers, as expected. This was true for granular materials such as Gerstley Borate and Borax; but it was also true for the flexible solid composed of boron carbide and rubber, even though only thin sheets were used. Experiments with small bundles of absorbers intentionally removed reveal that quite reasonable tanks could be constructed that would allow a few tubes at a time to be removed from the tank for inspection without removing the tank from production service

  19. Neutron physical investigations on the use of burnable poisons and gray absorber rods in large pressurized water reactors

    International Nuclear Information System (INIS)

    Brosche, C.; Katinger, T.; Kollmar, W.; Thieme, K.; Wagner, M.R.

    1977-11-01

    Methods and results of neutron physics calculations are described using burnable poisons and gray absorber rods in large PWR's. Calculated and measured values are compared, the effort for programming has been guessed. (orig.) [de

  20. A technique of measuring neutron spectrum

    International Nuclear Information System (INIS)

    Sarkar, P.K.; Kirthi, K.N.; Ganguly, A.K.

    1975-01-01

    Plastic scintillators have been used to measure fast neutron spectrum from various sources. Gamma background discrimination has been done by selecting thin scintillators and thereby achieving near 100% transmission of Compton-edge electrons. The measured distribution has been unfolded by using an iterative least square technique. This gives minimum variance and maximum likelihood estimate with error minimised. Smoothening of the observed distribution has been done by Fourier and time series analyses. The method developed is applicable in principle for the determination of spectra of high energy neutrons ranging from 1 MeV to 70 MeV and beyond. However, practical application of the method is limited by the non-availability of cross-section data for various neutron induced reactions with carbon and hydrogen present in the polymerised polystyrene scintillator. This procedure has been adopted in the present work for spectral determination up to 14 MeV neutrons using the published value of reaction and scattering cross-sections. The spectra of Po-Be, Pu-Be, Am-Be and Ra-Be arrived at agree well with the published spectra obtained by other methods. Spectrum from spontaneous fission of Cf-252 have also been measured and fitted to the expression N(E)=Esup(1/2)exp(-E/T). The fitted parameter T and spectral details agree well with those in published literature

  1. Synchrotron and neutron techniques in biological crystallography.

    Science.gov (United States)

    Blakeley, M P; Cianci, M; Helliwell, J R; Rizkallah, P J

    2004-10-20

    Synchrotron radiation (SR) techniques are continuously pushing the frontiers of wavelength range usage, smaller crystal sample size, larger protein molecular weight and complexity, as well as better diffraction resolution. The new research specialism of probing functional states directly in crystals, via time-resolved Laue and freeze trapping structural studies, has been developed, with a range of examples, based on research stretching over some 20 years. Overall, SR X-ray biological crystallography is complemented by neutron protein crystallographic studies aimed at cases where much more complete hydrogen details are needed involving synergistic developments between SR and neutron Laue methods. A big new potential exists in harnessing genome databases for targeting of new proteins for structural study. Structural examples in this tutorial review illustrate new chemistry learnt from biological macromolecules.

  2. Fabrication and characterization of dysprosia and alumina based inert matrix neutron absorbers

    International Nuclear Information System (INIS)

    D Ovidio, C.; Oliber, E.; Leiva, S.; Malachevsky, M. T; Taboada, H

    2009-01-01

    Among the elements of the lanthanides series, dysprosium has interesting nuclear properties. Its high thermal neutron absorption cross-section makes it a good neutron absorber. The best ceramic compound apt for nuclear use is its oxide, the disprosia (Dy 2 O 3 ). In order to fabricate neutron absorbers diluted in an inert matrix, it is relevant to study the preparation of a ceramic compound based on alumina (Al 2 O 3 ) and disprosia. In this work, we characterize a particular composition (44,5wt% Dy 2 O 3 , 55,5wt% Al 2 O 3 ) by determining the geometrical density, microstructure and phase formation. The chosen composition corresponds to the lowest temperature eutectic of the alumina-disprosia system, allowing the sintering to proceed at 1700 oC in air. Comparing the data of the green and sinterized pellets, the relative shrinking is of about 17 %, in the same proportion both for diameter and length. The corresponding volumetric reduction is of about 43 %, indicating an increase of the relative geometric density of ∼ 70 %. X-ray diffraction analysis shows the existence of two phases corresponding to the lower eutectic: Dy 3 Al 5 O 1 2 and Al 2 O 3 . The calculated theoretical density is ∼ 5.2 g/cm3. Consequently, the relative density of the pellets is 92 %, indicating the feasibility for the fabrication of the proposed material. In a near future, samples will be irradiated to evaluate their behavior for nuclear use. [es

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

    International Nuclear Information System (INIS)

    Fujine, Shigenori; Yoneda, Kenji; Yoshii, Koji; Kamata, Masahiro; Tamaki, Masayoshi; Ohkubo, Kohei; Ikeda, Yasushi; Kobayashi, Hisao

    1999-01-01

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

  4. More accurate thermal neutron coincidence counting technique

    International Nuclear Information System (INIS)

    Baron, N.

    1978-01-01

    Using passive thermal neutron coincidence counting techniques, the accuracy of nondestructive assays of fertile material can be improved significantly using a two-ring detector. It was shown how the use of a function of the coincidence count rate ring-ratio can provide a detector response rate that is independent of variations in neutron detection efficiency caused by varying sample moderation. Furthermore, the correction for multiplication caused by SF- and (α,n)-neutrons is shown to be separable into the product of a function of the effective mass of 240 Pu (plutonium correction) and a function of the (α,n) reaction probability (matrix correction). The matrix correction is described by a function of the singles count rate ring-ratio. This correction factor is empirically observed to be identical for any combination of PuO 2 powder and matrix materials SiO 2 and MgO because of the similar relation of the (α,n)-Q value and (α,n)-reaction cross section among these matrix nuclei. However the matrix correction expression is expected to be different for matrix materials such as Na, Al, and/or Li. Nevertheless, it should be recognized that for comparison measurements among samples of similar matrix content, it is expected that some function of the singles count rate ring-ratio can be defined to account for variations in the matrix correction due to differences in the intimacy of mixture among the samples. Furthermore the magnitude of this singles count rate ring-ratio serves to identify the contaminant generating the (α,n)-neutrons. Such information is useful in process control

  5. Visual inspections of the neutron absorber control rods of the IEA-R1 reactor

    International Nuclear Information System (INIS)

    Silva, Jose Eduardo R. da; Terremoto, Luis A.A.; Castanheira, Myrthes; Zeituni, Carlos A.; Damy, Margaret de A.

    2002-01-01

    The Fuel Engineering Division at IPEN/CNEN-SP developed facilities for visual inspection of the IEA-R1 fuel elements and neutron absorbing control rod assemblies inside the research reactor pool. This work presents the method of visual inspection performed at IEA-R1 research reactor. These inspections were adopted to evaluate and to follow the state of the Ag-In-Cd control assemblies fabricated at CERCA in 1972 that remain in use at the reactor core. In 1998, 2000 and 20001, visual inspections were performed in these control rod assemblies, which the general conditions were evaluated. (author)

  6. Effect of absorption discontinuity on neutron spectra of water assemblies poisoned with non-1/V absorbers

    International Nuclear Information System (INIS)

    Gupta, I.J.; Trikha, S.K.

    1977-01-01

    Calculations are presented of the diffusion of thermal neutrons (2.5 x 10 -4 to 7 x 10 -1 eV) across an absorption discontinuity in a water assembly, consisting of pure water on one side and aqueous solutions of three different non-1/V absorbers on the other, which were obtained by solving the Boltzmann transport equation in the diffusion approximation using the multigroup formalism. The gradual appearance and disappearance of the depletion region in the neutron spectra (caused by the resonance absorption peaks at energies 0.096 and 0.179 eV for samarium and cadmium respectively), as one moves from the pure water assembly to the poisoned water assembly and vice versa, have also been studied. The minimum concentrations of Sm and Cd atoms in water for which the depletion region in the spectra just starts building up are found to be 60 x 10 18 Sm atom cm -3 and 125 x 10 18 Cd atom cm -3 respectively. However no such depletion region is observed in gadolinium-poisoned water assembly. At the boundary, the equilibrium neutron distribution gets disturbed and is re-established to the equilibrium distribution of the second medium at some distance from the interface. The diffusion lengths so calculated from the total neutron density curves are in good agreement with the experimental results of Goddard and Johnson (Nucl. Sci. Eng.; 37:127 (1969)) at various concentrations of Gd and Cd atoms in water. (author)

  7. Lectures on neutron scattering techniques: 1

    International Nuclear Information System (INIS)

    Carlile, C.J.

    1988-08-01

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

  8. Preparation and characterization of ceramic neutron absorbers based on dysprosia and gadolinia

    International Nuclear Information System (INIS)

    Burgos, F.; Oliber, E.; Leiva S; Lestani, H.; Malachevsky, M.T.; Taboada, H.; D'Ovidio, C.

    2012-01-01

    Among the elements of the lanthanide series, dysprosium and gadolinium have interesting nuclear properties. Due to their high thermal neutron absorption cross-section they are good neutron absorbers. The only compounds suitable for nuclear use are their oxides, dysprosia (Dy 2 O 3 ) and gadolinia (Gd 2 O 3 ). To fabricate neutron absorbers diluted in an inert matrix, e.g. alumina (Al 2 O 3 ), it is relevant to study the preparation of a ceramic compound based on alumina (Al 2 O 3 ) and dysprosia or gadolinia. In this work, we characterize four different nominal compositions with high contents of gadolinia and dysprosia: (a) (45 wt% Dy 2 O 3 , 55 wt% Al 2 O 3 ), (b) (93 wt% Dy 2 O 3 , 7 wt% Al 2 O 3 ), (c) (50 wt% Gd 2 O 3 , 50 wt% Al 2 O 3 ) and (d) (90 wt% Gd 2 O 3 , 10 wt% Al 2 O 3 ). These compositions were selected as their stoichiometry correspond to the eutectic phases found in the respective phase diagrams, so as to attain sinterization at lower temperatures of approximately 1700 o C in air. The investigated parameters are the geometrical density of the pellets, the microstructure and the phases observed using x-ray diffraction. Contraction of the pellets was obtained by measuring the volumetric change between the green and the sintered samples. It was observed that the relative contraction was the same both in thickness and diameter. We discuss the eutectic phase formation and densification observed for the different compositions (author)

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

    Science.gov (United States)

    Sakurai, Yoshinori; Tanaka, Hiroki; Kondo, Natsuko; Kinashi, Yuko; Suzuki, Minoru; Masunaga, Shinichiro; Ono, Koji; Maruhashi, Akira

    2015-11-01

    Research and development of various accelerator-based irradiation systems for boron neutron capture therapy (BNCT) is underway throughout the world. Many of these systems are nearing or have started clinical trials. Before the start of treatment with BNCT, the relative biological effectiveness (RBE) for the fast neutrons (over 10 keV) incident to the irradiation field must be estimated. Measurements of RBE are typically performed by biological experiments with a phantom. Although the dose deposition due to secondary gamma rays is dominant, the relative contributions of thermal neutrons (below 0.5 eV) and fast neutrons are virtually equivalent under typical irradiation conditions in a water and/or acrylic phantom. Uniform contributions to the dose deposited from thermal and fast neutrons are based in part on relatively inaccurate dose information for fast neutrons. This study sought to improve the accuracy in the dose estimation for fast neutrons by using two phantoms made of different materials in which the dose components can be separated according to differences in the interaction cross sections. The development of a "dual phantom technique" for measuring the fast neutron component of dose is reported. One phantom was filled with pure water. The other phantom was filled with a water solution of lithium hydroxide (LiOH) capitalizing on the absorbing characteristics of lithium-6 (Li-6) for thermal neutrons. Monte Carlo simulations were used to determine the ideal mixing ratio of Li-6 in LiOH solution. Changes in the depth dose distributions for each respective dose component along the central beam axis were used to assess the LiOH concentration at the 0, 0.001, 0.01, 0.1, 1, and 10 wt. % levels. Simulations were also performed with the phantom filled with 10 wt. % 6LiOH solution for 95%-enriched Li-6. A phantom was constructed containing 10 wt. % 6LiOH solution based on the simulation results. Experimental characterization of the depth dose distributions of the

  10. Neutron logging reliability techniques and apparatus

    International Nuclear Information System (INIS)

    Johnstone, C.W.

    1975-01-01

    Apparatus and methods for verifying the validity of data derived at least in part by neutron logging of earth formations, and, where indicated, for affording neutron diffusion-corrected values of such data, are disclosed. (WHK)

  11. Absorbed bone marrow dose in certain dental radiographic techniques

    International Nuclear Information System (INIS)

    White, S.C.; Rose, T.C.

    1979-01-01

    The absorbed dose of radiation in the bone marrow of the region of the head and neck was measured during intraoral, panoramic, and cephalometric radiography. Panoramic radiography results in a dose a fifth or less than that from an intraoral survey. The use of rectangular collimation reduces the bone marrow absorbed dose from an intraoral survey by about 60%. Comparison of the doses from dental radiography with natural environmental radiation shows that an intraoral set of films results in the same total dose to the bone marrow as 65 days of background exposure. The use of rectangular collimation reduces this value to 25 days. Panoramic radiography results in significantly less irradiation, as it reduces the value to 14 days or fewer. Dental radiography thus involves exposures in the range of variation of natural environmental background values

  12. A new neutron noise technique for fast reactors

    International Nuclear Information System (INIS)

    Zhuo Fengguan; Jin Manyi; Yao Shigui; Su Zhuting

    1987-12-01

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

  13. Neutron diffraction measuring technique. A diffractometer for stress characterization

    International Nuclear Information System (INIS)

    Ceretti, M.; Lodini, A.

    1996-01-01

    The principles of the neutron diffraction technique for the characterization of stresses in materials, are presented and the two neutron generation techniques (high flux nuclear reactors and neutron spallation sources) are described together with the apparatus (monochromator, sample line, detectors (mainly 3 He detectors)); recommendations concerning alignment and positioning of the sample and sensor, determination of the reference distance, uncertainties on deformation values, are discussed

  14. RESPONSE FUNCTIONS FOR COMPUTING ABSORBED DOSE TO SKELETAL TISSUES FROM NEUTRON IRRADIATION

    Science.gov (United States)

    Bahadori, Amir A.; Johnson, Perry; Jokisch, Derek W.; Eckerman, Keith F.; Bolch, Wesley E.

    2016-01-01

    Spongiosa in the adult human skeleton consists of three tissues - active marrow (AM), inactive marrow (IM), and trabecularized mineral bone (TB). Active marrow is considered to be the target tissue for assessment of both long-term leukemia risk and acute marrow toxicity following radiation exposure. The total shallow marrow (TM50), defined as all tissues laying within the first 50 μm the bone surfaces, is considered to be the radiation target tissue of relevance for radiogenic bone cancer induction. For irradiation by sources external to the body, kerma to homogeneous spongiosa has been used as a surrogate for absorbed dose to both of these tissues, as direct dose calculations are not possible using computational phantoms with homogenized spongiosa. Recent microCT imaging of a 40-year-old male cadaver has allowed for the accurate modeling of the fine microscopic structure of spongiosa in many regions of the adult skeleton [Hough et al PMB (2011)]. This microstructure, along with associated masses and tissue compositions, was used to compute specific absorbed fractions (SAF) values for protons originating in axial and appendicular bone sites [Jokisch et al PMB (submitted)]. These proton SAFs, bone masses, tissue compositions, and proton production cross-sections, were subsequently used to construct neutron dose response functions (DRFs) for both AM and TM50 targets in each bone of the reference adult male. Kerma conditions were assumed for other resultant charged particles. For comparison, active marrow, total shallow marrow, and spongiosa kerma coefficients were also calculated. At low incident neutron energies, AM kerma coefficients for neutrons correlate well with values of the AM DRF, while total marrow (TM) kerma coefficients correlate well with values of the TM50 DRF. At high incident neutron energies, all kerma coefficients and DRFs tend to converge as charged particle equilibrium (CPE) is established across the bone site. In the range of 10 eV to 100 Me

  15. Application of the pulsed neutron technique on the reactors ALIZE - AQUILON (1963); Application de la methode des neutrons pulses sur les piles ALIZE et AQUILON (1963)

    Energy Technology Data Exchange (ETDEWEB)

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

    1963-07-01

    Different methods of measuring the ratio effective delayed fraction / prompt neutron lifetime, {alpha}{sub c}, are described. According to the classic pulsed neutron technique the negative reactivity due to a localized absorber is given by {rho} / {beta}{sub eff} = {alpha} / {alpha}{sub c} -1 Experiments are reported which show that in this case {alpha}{sub c} can not be considered constant for large reactivities. The absorber element distorts the flux in the system, increasing the importance of the reflector. An application of the pulsed neutron method to the measurement of critical distributed boron concentrations of various absorber elements is described. Less time is required than for the usual super-critical techniques, and the experimental analysis is simplified. It is interesting to note that the results are not influenced by the spectral sensitivity of the control element. A modified pulsed neutron method has been tried out. This procedure was used to determine by measurements at sub-critical the critical water level of uranium-heavy water lattices with a high precision. (author) [French] Differents modes operatoires pour definir la valeur du rapport pourcentage effectif de neutrons retardes / temps de vie, {alpha}{sub c}, sont exposes. La methode classique par neutrons pulses definit l'anti-reactivite d'un element absorbant a partir de la relation: {rho} / {beta}{sub eff} {alpha} / {alpha}{sub c} -1 Les manipulations effectuees montrent qu'on ne peut considerer dans ce cas {alpha}{sub c} constant pour de tres grandes anti-reactivites. L'absorbant introduit dans la pile deforme le flux et augmente l'importance du reflecteur. Une application de la methode des neutrons pulses pour mesurer le titre critique en mg de B/l de divers absorbants est signalee. Les operations sont effectuees en regime sous-critique avec un certain gain de temps et une grande facilite de depouillement. Il est interessant de noter que les resultats ne sont pas

  16. Enriched boric acid as an optimized neutron absorber in the EPR primary coolant

    International Nuclear Information System (INIS)

    Cosse, Christelle; Jolivel, Fabienne; Berger, Martial

    2012-09-01

    This paper focuses on one of the most important EPR PWR reactor design optimizations, through primary coolant conditioning by enriched boric acid (EBA). On PWRs throughout the world, boric acid has already been implemented in primary coolant and associated auxiliary systems for criticality control, due to its high Boron 10 neutron absorption cross section. Boric acid also allows primary coolant pH 300C control in combination with lithium hydroxide in many PWRs. The boric acid employed in the majority of existing PWRs is the 'natural' one, with a typical isotopic atomic abundance in Boron 10 about 19.8 at.%. However, EPR requirements for neutron management are more important, due to its fully optimized design compared to older PWRs. From the boron point of view, it means that criticality could be controlled either by increased 'natural' Boron concentrations or by using EBA. Comparatively to 'natural' boric acid, EBA allows for: - the use of smaller storage volumes for an identical total Boron concentration, or lower total Boron concentration if the tank volumes are kept identical. The latter also reduces the risks of boric acid crystallization, in spite of increased neutron-absorbing properties - the application of an evolutionary chemistry operating regime called Advanced pH Control, making it possible to maintain a constant pH 300C value at 7.2 in the primary coolant at nominal conditions throughout entire cycles. This optimized stability of pH 300C will contribute to reduce the consequences of contamination of the reactor coolant system by corrosion products, and consequently, all related issues - the reduction of borated liquid wastes, thanks to maximal recycling resulting from EPR design. The increased design costs associated with EBA are consequently compensated by a reduced total consumption of this chemical. Therefore, the basic design choice for the EPR is the use of EBA. For the Flamanville 3 EPR, according to the above

  17. Application of eV neutron scattering and eV neutron absorption techniques

    International Nuclear Information System (INIS)

    Ikeda, S.

    1989-01-01

    Intense spallation neutron sources can provide a useful eV neutron flux in the energy range 1-100 eV, which is much more intense than has ever been available from steady state sources, and makes two fruitful techniques possible. One is an eV neutron scattering technique, which allows the impulse approximation limit to be approached. The other is an eV neutron absorption technique. Both have been used to observe the motions of specific atoms in the high temperature superconducting systems La-Cu-O and Y-Ba-Cu-O. The procedure and experimental layout are given. Neutron scattering and neutron absorption spectra are presented for different temperatures. These allowed effective temperatures of atoms in the high T c materials to be found. (author)

  18. Micro structural evaluation technique of steel using neutron beam

    International Nuclear Information System (INIS)

    Nakamichi, Haruo; Sato, Kaoru; Sueyoshi, Hitoshi

    2016-01-01

    Structural analysis using Neutrons is a very unique technique for its strong penetration ability through steels. Numerous evaluation techniques are available at present, and JFE Steel has been adapting the technique through participating in research activities such as in the Iron and Steel Institute of Japan. This paper introduces some results including precipitation evaluation using a small angle scattering, residual strain estimation through diffractions, and in-situ transformation observation by time-of-flight methods of neutron beams diffraction. (author)

  19. Neutron therapy coupling brachytherapy and boron neutron capture therapy (BNCT) techniques

    International Nuclear Information System (INIS)

    Chaves, Iara Ferreira.

    1994-12-01

    In the present dissertation, neutron radiation techniques applied into organs of the human body are investigated as oncologic radiation therapy. The proposal treatment consists on connecting two distinct techniques: Boron Neutron Capture Therapy (BNCT) and irradiation by discrete sources of neutrons, through the brachytherapy conception. Biological and radio-dosimetrical aspects of the two techniques are considered. Nuclear aspects are discussed, presenting the nuclear reactions occurred in tumoral region, and describing the forms of evaluating the dose curves. Methods for estimating radiation transmission are reviewed through the solution of the neutron transport equation, Monte Carlo methodology, and simplified analytical calculation based on diffusion equation and numerical integration. The last is computational developed and presented as a quickly way to neutron transport evaluation in homogeneous medium. The computational evaluation of the doses for distinct hypothetical situations is presented, applying the coupled techniques BNTC and brachytherapy as an possible oncologic treatment. (author). 78 refs., 61 figs., 21 tabs

  20. Experimental techniques for the consolidation of the neutron spectrum

    International Nuclear Information System (INIS)

    Chiaraviglio, N.; Bazzana, S.

    2013-01-01

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

  1. Application of neutron backscatter techniques to level measurement problems

    International Nuclear Information System (INIS)

    Leonardi-Cattolica, A.M.; McMillan, D.H.; Telfer, A.; Griffin, L.H.; Hunt, R.H.

    1982-01-01

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

  2. Application of eV neutron scattering and eV neutron absorption techniques

    International Nuclear Information System (INIS)

    Ikeda, Susumu

    1989-01-01

    Intense spallation neutron sources can provide a useful eV neutron flux in the energy range 1-100 eV, which is much more intense than has even been available from steady-state sources, and makes two fruitful techniques possible. One is an eV neutron scattering technique. The other is an eV neutron absorption technique. The discovery of superconductivity in the temperature range 30-100 K for the La-Cu-O system and the Y-Ba-Cu-O system is one of the most exciting events in recent solid state physics. Many attempts to explain such extraordinary high Tc values have been made with conventional electron-phonon coupling theory as well as with non-phonon mechanisms. The most direct test for such theories is to look for predicted excitations by using inelastic neutron scattering techniques. The eV neutron scattering and eV neutron absorption experiments can provide new important information for the high Tc mechanism, which has never been obtained by ordinary neutron scattering experiments. For the first time, the author applies these methods to the observation of motions of specific atoms in La-Cu-O and Y-Ba-Cu-O systems. In this paper, he reports a procedure of the application. 17 refs., 8 figs., 1 tab

  3. Steel research using neutron beam techniques. In-situ neutron diffraction, small-angle neutron scattering and residual stress analysis

    International Nuclear Information System (INIS)

    Sueyoshi, Hitoshi; Ishikawa, Nobuyuki; Yamada, Katsumi; Sato, Kaoru; Nakagaito, Tatsuya; Matsuda, Hiroshi; Arakaki, Yu; Tomota, Yo

    2014-01-01

    Recently, the neutron beam techniques have been applied for steel researches and industrial applications. In particular, the neutron diffraction is a powerful non-destructive method that can analyze phase transformation and residual stress inside the steel. The small-angle neutron scattering is also an effective method for the quantitative evaluation of microstructures inside the steel. In this study, in-situ neutron diffraction measurements during tensile test and heat treatment were conducted in order to investigate the deformation and transformation behaviors of TRIP steels. The small-angle neutron scattering measurements of TRIP steels were also conducted. Then, the neutron diffraction analysis was conducted on the high strength steel weld joint in order to investigate the effect of the residual stress distribution on the weld cracking. (author)

  4. Image reconstruction technique for neutron penumbra imaging

    International Nuclear Information System (INIS)

    Liu Dongjian

    2006-01-01

    The principle of the neutron penumbra imaging was introduced, and the effect factors of the resolution of the imaging system were analyzed. The neutron penumbra imaging process was simulated with MCNP software. The coded image of one point source on the imaging principal axis and that of two point sources off the principal axis with and without noise and back-ground were reconstructed by the improved inverse filter and Wiener filter method respectively. The simulation results indicated that the Wiener filter method could restrain noise better. (authors)

  5. Selection of neutron-absorbing materials to improve the low-energy response of a Zr-based extended neutron monitor using Monte Carlo simulations.

    Science.gov (United States)

    Biju, K; Sunil, C; Tripathy, S P; Joshi, D S; Bandyopadhyay, T; Sarkar, P K

    2015-02-01

    Monte Carlo simulations have been carried out using the FLUKA code to improve the neutron ambient dose equivalent [H*(10)] response of the ZReC (zirconium-lined portable neutron counter responding satisfactorily to neutrons up to 1 GeV) by introducing various neutron absorbers in the system such as cadmium, gadolinium, natural boron, enriched (10)B and borated polythene. It was found that ZReC can be effectively used as a portable neutron monitor by introducing any one of the following perforated layers: 5 mm thick natural boron, 0.5 mm thick enriched (10)B or 1 cm high-density polythene mixed with 50 % boron by weight. The integral response of the instrument was also calculated for some typical reference neutron fields. The relative ambient dose equivalent response of the said system is also found comparable with that of the existing LINUS neutron monitor. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Experimental technique of small angle neutron scattering

    International Nuclear Information System (INIS)

    Xia Qingzhong; Chen Bo

    2006-03-01

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

  7. Measurement of epithermal neutrons by a coherent demodulation technique

    CERN Document Server

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

    2000-01-01

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

  8. Stress measurement technique using neutron diffraction and its applications

    International Nuclear Information System (INIS)

    Suzuki, Hiroshi

    2010-01-01

    Neutron diffraction is the only method by which residual stresses inside materials at centimeter-order depth can be measured nondestructively. Residual lattice strains in (hkl) can be evaluated from the shift of the diffraction peak from its original position under the stress-free condition. Residual stresses can be calculated by applying Hooke's law to lattice strains measured in three orthogonal directions. In addition, the neutron diffraction method can evaluate macroscopic deformation of engineering materials by measuring microstructural factors such as microstrains. Therefore, the neutron diffraction technique is very helpful in the design and development of engineering components, as well as in studies on materials engineering. This paper shows principle of neutron stress measurement and engineering neutron diffractometers as well as some applications. (author)

  9. A survey on development of neutron standards and neutron measurement technique corresponding to various fields

    International Nuclear Information System (INIS)

    Matsumoto, Tetsuro

    2007-01-01

    Various uses of neutrons are being watched in many fields such as industry, medical technology and radiation protection. Especially, high energy neutrons above 15 MeV are important in a radiation exposure issue of an aircraft and a soft error issue of a semiconductor. Therefore neutron fluence standards for the high energy region are very important. However, the standards are not almost provided all over the world. Three reasons are mainly considered: (1) poor measurement techniques for the high energy neutrons, (2) a small number of high energy neutron facilities and (3) lack of nuclear data for high energy particle reactions. In this paper, the present status of the measurement techniques, the facilities and the nuclear data is investigated and discussed. In NMIJ/AIST, the 19.0-MeV neutron fluence standard will be established by 2010, and development of high energy neutron standards above 20 MeV is also examined. An outline of the development of the high energy neutron standards is also shown in this paper. (author)

  10. Standard specification for boron-Based neutron absorbing material systems for use in nuclear spent fuel storage racks

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This specification defines criteria for boron-based neutron absorbing material systems used in racks in a pool environment for storage of nuclear light water reactor (LWR) spent-fuel assemblies or disassembled components to maintain sub-criticality in the storage rack system. 1.2 Boron-based neutron absorbing material systems normally consist of metallic boron or a chemical compound containing boron (for example, boron carbide, B4C) supported by a matrix of aluminum, steel, or other materials. 1.3 In a boron-based absorber, neutron absorption occurs primarily by the boron-10 isotope that is present in natural boron to the extent of 18.3 ± 0.2 % by weight (depending upon the geological origin of the boron). Boron, enriched in boron-10 could also be used. 1.4 The materials systems described herein shall be functional – that is always be capable to maintain a B10 areal density such that subcriticality Keff <0.95 or Keff <0.98 or Keff < 1.0 depending on the design specification for the service...

  11. First-principles investigation of neutron-irradiation-induced point defects in B4C, a neutron absorber for sodium-cooled fast nuclear reactors

    Science.gov (United States)

    You, Yan; Yoshida, Katsumi; Yano, Toyohiko

    2018-05-01

    Boron carbide (B4C) is a leading candidate neutron absorber material for sodium-cooled fast nuclear reactors owing to its excellent neutron-capture capability. The formation and migration energies of the neutron-irradiation-induced defects, including vacancies, neutron-capture reaction products, and knocked-out atoms were studied by density functional theory calculations. The vacancy-type defects tend to migrate to the C–B–C chains of B4C, which indicates that the icosahedral cage structures of B4C have strong resistance to neutron irradiation. We found that lithium and helium atoms had significantly lower migration barriers along the rhombohedral (111) plane of B4C than perpendicular to this plane. This implies that the helium and lithium interstitials tended to follow a two-dimensional diffusion regime in B4C at low temperatures which explains the formation of flat disk like helium bubbles experimentally observed in B4C pellets after neutron irradiation. The knocked-out atoms are considered to be annihilated by the recombination of the close pairs of self-interstitials and vacancies.

  12. Skin Absorbed Doses from Full Mouth Standard Intraoral Radiography in Bisecting Angle and Paralleling techniques

    Energy Technology Data Exchange (ETDEWEB)

    Nah, Kyung Soo; Kim, Ae Ji [Dept. of Oral Radiology, College of Dentistry, Pusan National University, Pusan (Korea, Republic of); Doh, Shi Hong [Dept. of Applied physics . National Fisheries University of Pusan Department of Radiotherapy, Pusan (Korea, Republic of); Kim, Hyun Ja [Dept. of Oral Radiology, Baptist Hospital, Pusan (Korea, Republic of); Yoo, Meong Jin [Dept. of Radiology, College of Dentistry, Pusan National University, Pusan (Korea, Republic of)

    1990-08-15

    This study was performed to measure the skin absorbed doses from full mouth standard intraoral radiography(14 exposures) in bisecting angle and paralleling techniques. Thermoluminescent dosimeters were used in a phantom. Circular tube collimator (60 mm in diameter, 20 cm in length) and rectangular collimator (35 mm X 44 mm, 40 cm in length) were set for bisecting angle and paralleling techniques respectively. All measurement sites were classified into 8 groups according to distance from each point of central rays. The results were as follows: 1. The skin absorbed doses from the paralleling technique were significantly decreased than those from the bisecting technique in both points at central ray and points away from central ray. The percentage rats of decrease were greater at points away from central ray than those at central ray. 2. The skin absorbed doses at the lens of eye, parotid gland, submandibular gland and thyroid region were significantly decreased in paralleling technique, but those of the midline of palate remained similar in both techniques. 3. The highest doses were measured at the site 20 mm above the point of central ray for the mandibular premolars in bisecting angle technique and at the point of central ray for the mandibular premolars in paralleling techniques. The lowest doses were measured at the thyroid region in both techniques.

  13. Skin Absorbed Doses from Full Mouth Standard Intraoral Radiography in Bisecting Angle and Paralleling techniques

    International Nuclear Information System (INIS)

    Nah, Kyung Soo; Kim, Ae Ji; Doh, Shi Hong; Kim, Hyun Ja; Yoo, Meong Jin

    1990-01-01

    This study was performed to measure the skin absorbed doses from full mouth standard intraoral radiography(14 exposures) in bisecting angle and paralleling techniques. Thermoluminescent dosimeters were used in a phantom. Circular tube collimator (60 mm in diameter, 20 cm in length) and rectangular collimator (35 mm X 44 mm, 40 cm in length) were set for bisecting angle and paralleling techniques respectively. All measurement sites were classified into 8 groups according to distance from each point of central rays. The results were as follows: 1. The skin absorbed doses from the paralleling technique were significantly decreased than those from the bisecting technique in both points at central ray and points away from central ray. The percentage rats of decrease were greater at points away from central ray than those at central ray. 2. The skin absorbed doses at the lens of eye, parotid gland, submandibular gland and thyroid region were significantly decreased in paralleling technique, but those of the midline of palate remained similar in both techniques. 3. The highest doses were measured at the site 20 mm above the point of central ray for the mandibular premolars in bisecting angle technique and at the point of central ray for the mandibular premolars in paralleling techniques. The lowest doses were measured at the thyroid region in both techniques.

  14. Microstructure Analysis of Neutron Absorber Al/B4C Metal Matrix Composites

    Directory of Open Access Journals (Sweden)

    Jianxin Lin

    2017-12-01

    Full Text Available The microstructure of Al/B4C metal matrix composites (MMCs used as neutron absorbers in both dry storage casks and wet storage pools of spent nuclear fuel was analyzed by SEM and TEM. A polishing method of a focused Ga+ ion beam was used to obtain an ideal sample surface with very low roughness, which was used to statistically analyze the distribution characteristics and size factor of B4C particles in the aluminum matrix. The area of B4C particles mainly ranged from 0 to 0.5 μm2, which was the proportion of 64.29%, 86.99% and 76.86% of total statistical results for the Al-15%B4C, Al-25%B4C and Al-30%B4C MMCs, respectively. The average area of B4C particles in the Al-15%B4C, Al-25%B4C and Al-30%B4C MMCs were about 1.396, 0.528 and 1.183 μm2, respectively. The nanoscale precipitates were analyzed by the element mappings in scanning transmission electron microscopy (STEM mode and electron energy loss spectroscopy (EELS mode, which included elliptic alloy precipitates with elemental Cu, Cr, Fe and Si, except for Al, and B4C nanoparticles with polygonal shape. The interface characteristics showed that the (021 crystal plane of B4C particle and (111 crystal plane of aluminum matrix grew together. The lattice misfit was about 1.68% for (111Al//(021B4C. The corrosion properties and corresponding mechanism of Al/B4C MMCs were investigated in an aqueous solution with 5000 ppm boric acid at 100 °C and atmospheric pressure, which showed that the mass increment rate was first decreased with increasing corrosion time and then increased.

  15. Evaluation of Aluminum-Boron Carbide Neutron Absorbing Materials for Interim Storage of Used Nuclear Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lumin [Univ. of Michigan, Ann Arbor, MI (United States). Department of Nuclear Engineering and Radiological Science; Wierschke, Jonathan Brett [Univ. of Michigan, Ann Arbor, MI (United States). Department of Nuclear Engineering and Radiological Science

    2015-04-08

    The objective of this work was to understand the corrosion behavior of Boral® and Bortec® neutron absorbers over long-term deployment in a used nuclear fuel dry cask storage environment. Corrosion effects were accelerated by flowing humidified argon through an autoclave at temperatures up to 570°C. Test results show little corrosion of the aluminum matrix but that boron is leaching out of the samples. Initial tests performed at 400 and 570°C were hampered by reduced flow caused by the rapid build-up of solid deposits in the outlet lines. Analysis of the deposits by XRD shows that the deposits are comprised of boron trioxide and sassolite (H3BO3). The collection of boron- containing compounds in the outlet lines indicated that boron was being released from the samples. Observation of the exposed samples using SEM and optical microscopy show the growth of new phases in the samples. These phases were most prominent in Bortec® samples exposed at 570°C. Samples of Boral® exposed at 570°C showed minimal new phase formation but showed nearly the complete loss of boron carbide particles. Boron carbide loss was also significant in Boral samples at 400°C. However, at 400°C phases similar to those found in Bortec® were observed. The rapid loss of the boron carbide particles in the Boral® is suspected to inhibit the formation of the new secondary phases. However, Material samples in an actual dry cask environment would be exposed to temperatures closer to 300°C and less water than the lowest test. The results from this study conclude that at the temperature and humidity levels present in a dry cask environment, corrosion and boron leaching will have no effect on the performance of Boral® and Bortec® to maintain criticality control.

  16. X-ray and neutron techniques for nanomaterials characterization

    CERN Document Server

    2016-01-01

    Fifth volume of a 40 volume series on nanoscience and nanotechnology, edited by the renowned scientist Challa S.S.R. Kumar. This handbook gives a comprehensive overview about X-ray and Neutron Techniques for Nanomaterials Characterization. Modern applications and state-of-the-art techniques are covered and make this volume an essential reading for research scientists in academia and industry.

  17. Nondestructive control of chemical weapons combining neutron-activation analysis and neutron-radiography techniques

    Science.gov (United States)

    Bach, Pierre; Cluzeau, S.; Le Tourneur, P.; Jaureguy, J. C.; Guir, F.

    1995-03-01

    A project of a transportable neutron system has been designed for nondestructive detection of weapon materials such as chemical agents or explosives. The system combines imaging and identifying techniques, and uses a sealed tube neutron generator GENIE 46. The neutron emitting module is embedded in a moderator/collimator. The resulting mixed 14 MeV and thermal neutron beam allows the user to perform neutron radiography and gamma-ray spectroscopy. Substances to be detected are imaged in a first step and then identified by comparing relative spectral line intensities with those of reference materials. The moderator provides a first level protection against radiation to the operators. This project includes only industrial sub assemblies, transportable by truck to be used in open area.

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

    International Nuclear Information System (INIS)

    Eissa, E.A.; Rofail, N.B.; Hassan, A.M.; El-Shershaby, A.; Walley El-Dine, N.

    1996-01-01

    Two brazing alloy samples (C P 2 and C P 3 ) have been investigated by Neutron activation analysis (NAA) technique in order to identify and estimate their constituent elements. The pneumatic irradiation rabbit system (PIRS), installed at the first egyptian research reactor (ETRR-1) was used for short-time irradiation (30 s) with a thermal neutron flux of 1.6 x 10 1 1 n/cm 2 /s in the reactor reflector, where the thermal to epithermal neutron flux ratio is 106. Long-time irradiation (48 hours) was performed at reactor core periphery with thermal neutron flux of 3.34 x 10 1 2 n/cm 2 /s, and thermal to epithermal neutron flux ratio of 79. Activation by epithermal neutrons was taken into account for the (1/v) and resonance neutron absorption in both methods. A hyper pure germanium detection system was used for gamma-ray acquisitions. The concentration values of Al, Cr, Fe, Co, Cu, Zn, Se, Ag and Sb were estimated as percentages of the sample weight and compared with reported values. 1 tab

  19. Lattice strain measurement in rock sample by neutron diffraction technique

    International Nuclear Information System (INIS)

    Abe, Jun; Ito, Takayoshi; Sekine, Kotaro; Harjo, Stefanus; Aizawa, Kazuya

    2015-01-01

    Strain gauge and mechanical extensometers are commonly used to measure strain in rock samples. In recent years, diffraction techniques with X-rays and neutrons for investigating strain in engineering materials have been developed. Strain measurements using diffraction technique are based on Bragg's law. Lattice spacing changes with strain, which induces peak shift of Bragg peak. Strain value can be estimated from this peak shift value. Strain measurements using the world's highest intensity neutron beam can be performed at Japan Proton Accelerator Research Complex (J-PARC) constructed at Tokai in Ibaraki. Neutron powder diffractometer dedicating to investigate strain state in engineering materials has been constructed at BL19 in J-PARC, which is named as The Engineering Materials Diffractometer 'TAKUMI'. In order to examine applicability of the diffractometer to rock materials, in situ neutron diffraction experiments on rock samples under uni-axial compression have been performed. Higher resolution strain data has been obtained in shorter time compared to other diffractometers. In addition, neutron diffraction peaks of not only major component, such as quartz, but also minor components, such as feldspars, could be observed. Anisotropy of strain with respect to the quartz crystal orientation and discrepancy between macroscopic strain (measured by strain gauge) and lattice strain (measured by neutron diffraction) were also recognized. Change in peak width with respect to stress magnitude showed a different behavior depending on rock type. Strain measurements using neutron diffraction technique give us new insight in rock deformation which cannot be obtained by common technique. (author)

  20. Neutron radiography activity in the european program cost 524: Neutron imaging techniques

    International Nuclear Information System (INIS)

    Chirco, P.; Bach, P.; Lehmann, E.; Balasko, M.

    2001-01-01

    COST is a framework for scientific and technical cooperation, allowing the coordination of national research on a European level, including 32 member countries. Participation of institutes from non-COST countries is possible. From an initial 7 Actions in 1971, COST has grown to 200 Actions at the beginning of 2000. COST Action 524 is under materials domain, the title of which being 'Neutron Imaging Techniques for the Detection of Defects in Materials', under the Chairmanship of Dr. P. Chirco (I.N.F.N.). The following countries are represented in the Management Committee of Action 524: Italy, France, Austria, Germany, United Kingdom, Hungary, Switzerland, Spain, Czech Republic, Slovenia, and Russia. The six working groups of this Action are working respectively on standardization of neutron radiography techniques, on aerospace application, on civil engineering applications, on comparison and integration of neutron imaging techniques with other NDT, on neutron tomography, and on non radiographic techniques such as neutron scattering techniques. A specific effort is devoted to standardization issues, with respect to other non European standards. Results of work performed in the COST frame are published or will be published in the review INSIGHT, edited by the British Institute of Non Destructive Testing

  1. Burnable absorber-integrated Guide Thimble (BigT) - 1. Design concepts and neutronic characterization on the fuel assembly benchmarks

    International Nuclear Information System (INIS)

    Yahya, Mohd-Syukri; Yu, Hwanyeal; Kim, Yonghee

    2016-01-01

    This paper presents the conceptual designs of a new burnable absorber (BA) for the pressurized water reactor (PWR), which is named 'Burnable absorber-integrated Guide Thimble' (BigT). The BigT integrates BA materials into standard guide thimble in a PWR fuel assembly. Neutronic sensitivities and practical design considerations of the BigT concept are points of highlight in the first half of the paper. Specifically, the BigT concepts are characterized in view of its BA material and spatial self-shielding variations. In addition, the BigT replaceability requirement, bottom-end design specifications and thermal-hydraulic considerations are also deliberated. Meanwhile, much of the second half of the paper is devoted to demonstrate practical viability of the BigT absorbers via comparative evaluations against the conventional BA technologies in representative 17x17 and 16x16 fuel assembly lattices. For the 17x17 lattice evaluations, all three BigT variants are benchmarked against Westinghouse's existing BA technologies, while in the 16x16 assembly analyses, the BigT designs are compared against traditional integral gadolinia-urania rod design. All analyses clearly show that the BigT absorbers perform as well as the commercial BA technologies in terms of reactivity and power peaking management. In addition, it has been shown that sufficiently high control rod worth can be obtained with the BigT absorbers in place. All neutronic simulations were completed using the Monte Carlo Serpent code with ENDF/B-VII.0 library. (author)

  2. Neutron spectral modulation as a new thermal neutron scattering technique. Pt. 1

    International Nuclear Information System (INIS)

    Ito, Y.; Nishi, M.; Motoya, K.

    1982-01-01

    A thermal neutron scattering technique is presented based on a new idea of labelling each neutron in its spectral position as well as in time through the scattering process. The method makes possible the simultaneous determination of both the accurate dispersion relation and its broadening by utilizing the resolution cancellation property of zero-crossing points in the cross-correlated time spectrum together with the Fourier transform scheme of the neutron spin echo without resorting to the echoing. The channel Fourier transform applied to the present method also makes possible the determination of the accurate direct energy scan profile of the scattering function with a rather broad incident neutron wavelength distribution. Therefore the intensity sacrifice for attaining high accurarcy is minimized. The technique is used with either a polarized or unpolarized beam at the sample position with no precautions against beam depolarization at the sample for the latter case. Relative time accurarcy of the order of 10 -3 to 10 -4 may be obtained for the general dispersion relation and for the quasi-elastic energy transfers using correspondingly the relative incident neutron wavelength spread of 10 to 1% around an incident neutron energy of a few meV. (orig.)

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

    International Nuclear Information System (INIS)

    Overbury, Steven H.; Coates, Leighton; Herwig, Kenneth W.; Kidder, Michelle

    2011-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-10-01

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

  5. Measurement of the neutron detection efficiency of a 80% absorber-20% scintillating fibers calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Anelli, M.; Bertolucci, S. [Laboratori Nazionali di Frascati dell' INFN, Via E.Fermi 40, I-00044 Frascati (Italy); Bini, C., E-mail: cesare.bini@roma1.infn.i [Dipartimento di Fisica, Sapienza Universita di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); INFN Sezione di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); Branchini, P. [INFN Sezione di Roma Tre, Via della Vasca Navale, 84 I-00146 Roma (Italy); Corradi, G.; Curceanu, C. [Laboratori Nazionali di Frascati dell' INFN, Via E.Fermi 40, I-00044 Frascati (Italy); De Zorzi, G.; Di Domenico, A. [Dipartimento di Fisica, Sapienza Universita di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); INFN Sezione di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); Di Micco, B. [Dipartimento di Fisica dell' Universita ' Roma Tre' , Via della Vasca Navale, 84 I-00146 Roma (Italy); INFN Sezione di Roma Tre, Via della Vasca Navale, 84 I-00146 Roma (Italy); Ferrari, A. [Institute of Safety Research and Institute of Radiation Physics, Forschungszentrum Dresden-Rossendorf, PF 510119, 01314 Dresden (Germany); Fiore, S. [Dipartimento di Fisica, Sapienza Universita di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); INFN Sezione di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); Gauzzi, P., E-mail: paolo.gauzzi@roma1.infn.i [Dipartimento di Fisica, Sapienza Universita di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); INFN Sezione di Roma, P.le A.Moro, 2 I-00185 Roma (Italy); Giovannella, S.; Happacher, F. [Laboratori Nazionali di Frascati dell' INFN, Via E.Fermi 40, I-00044 Frascati (Italy); Iliescu, M. [Laboratori Nazionali di Frascati dell' INFN, Via E.Fermi 40, I-00044 Frascati (Italy); ' Horia Hulubei' National Institute of Physics and Nuclear Engineering, Str. Atomistilor no. 407, P.O. Box MG-6 Bucharest-Magurele (Romania); Luca, A.; Martini, M.; Miscetti, S. [Laboratori Nazionali di Frascati dell' INFN, Via E.Fermi 40, I-00044 Frascati (Italy)

    2011-01-21

    The neutron detection efficiency of a sampling calorimeter made of 1 mm diameter scintillating fibers embedded in a lead/bismuth structure has been measured at the neutron beam of The Svedberg Laboratory at Uppsala. A significant enhancement of the detection efficiency with respect to a bulk organic scintillator detector with the same thickness is observed.

  6. Neutron diffraction technique as a method for material studies

    International Nuclear Information System (INIS)

    Belhorma, B.; Labrim, H.; Gandou, Z.

    2010-01-01

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

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

    Science.gov (United States)

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

    2016-09-01

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

  8. Study on an innovative fast reactor utilizing hydride neutron absorber - Final report of phase I study

    International Nuclear Information System (INIS)

    Konashi, K.; Iwasaki, T.; Itoh, K.; Hirai, M.; Sato, J.; Kurosaki, K.; Suzuki, A.; Matsumura, Y.; Abe, S.

    2010-01-01

    These days, the demand to use nuclear resources efficiently is growing for long-term energy supply and also for solving the green house problem. It is indispensable to develop technologies to reduce environmental load with the nuclear energy supply for sustainable development of human beings. In this regard, the development of the fast breeder reactor (FBR) is preferable to utilize nuclear resources effectively and also to burn minor actinides which possess very long toxicity for more than thousands years if they are not extinguished. As one of the FBR developing works in Japan this phase I study started in 2006 to introduce hafnium (Hf) hydride and Gadolinium-Zirconium (Gd-Zr) hydride as new control materials in FBR. By adopting them, the FBR core control technology is improved by two ways. One is extension of control rod life time by using long life Hf hydride which leads to reduce the fabrication and disposal cost and the other is reduction of the excess reactivity by adopting Gd-Zr hydride which leads to reduce the number of control rods and simplifies the core upper structure. This three year study was successfully completed and the following results were obtained. The core design was performed to examine the applicability of the Hf hydride absorber to Japanese Sodium Fast Reactor (JSFR) and it is clarified that the control rod life time can be prolonged to 6 years by adopting Hf hydride and the excess reactivity of the beginning of the core cycle can be reduced to half and the number of the control rods is also reduced to half by using the Gd-Zr hydride burnable poison. The safety analyses also certified that the core safety can be maintained with the same reliability of JSFR Hf hydride and Gd-Zr hydride pellets were fabricated in good manner and their basic features for design use were measured by using the latest devices such as SEM-EDX. In order to reduce the hydrogen transfer through the stainless steel cladding a new technique which shares calorizing

  9. Visual inspections of the neutron absorber control rods of the IEA-R1 reactor; Inspecoes visuais nas barras absorvedoras de neutrons do reator IEA-R1

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jose Eduardo R. da; Terremoto, Luis A.A.; Castanheira, Myrthes; Zeituni, Carlos A.; Damy, Margaret de A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear]. E-mail: jersilva@net.ipen.br

    2002-07-01

    The Fuel Engineering Division at IPEN/CNEN-SP developed facilities for visual inspection of the IEA-R1 fuel elements and neutron absorbing control rod assemblies inside the research reactor pool. This work presents the method of visual inspection performed at IEA-R1 research reactor. These inspections were adopted to evaluate and to follow the state of the Ag-In-Cd control assemblies fabricated at CERCA in 1972 that remain in use at the reactor core. In 1998, 2000 and 20001, visual inspections were performed in these control rod assemblies, which the general conditions were evaluated. (author)

  10. RBE/absorbed dose relationship of d(50)-Be neutrons determined for early intestinal tolerance in mice

    International Nuclear Information System (INIS)

    Gueulette, J.; Wambersie, A.

    1978-01-01

    RBE/absorbed dose relationship of d(50)-Be neutrons (ref.: 60 Co) was determined using intestinal tolerance in mice (LD50) after single and fractionated irradiation. RBE is 1.8 for a single fraction (about 1000 rad 60 Co dose); it increases when decreasing dose and reaches the plateau value of 2.8 for a 60 Co dose of about 200 rad. This RBE value is used for the clinical applications with the cyclotron 'Cyclone' at Louvain-la-Neuve [fr

  11. Spectra and absorbed dose by photo-neutrons in a solid water mannequin exposed to a Linac of 15 MV

    International Nuclear Information System (INIS)

    Benites R, J.; Vega C, H. R.; Velazquez F, J.

    2012-10-01

    Using Monte Carlo methods was modeled a solid water mannequin; according to the ICRU 44 (1989), Tissue substitutes in radiation dosimetry and measurements, of the International Commission on Radiation Units and Measurements; Report 44. This material Wt 1 is made of H (8.1%), C (67.2%), N (2.4%), O (19.9%), Cl (0.1%), Ca (2.3%) and its density is of 1.02 gr/cm 3 . The mannequin was put instead of the patient, inside the treatment room and the spectra and absorbed dose were determined by photo-neutrons exposed to a Linac of 15 MV. (Author)

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

    CERN Document Server

    Singh, S

    2002-01-01

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

  13. Alternative technique to neutron probe calibration in situ

    International Nuclear Information System (INIS)

    Encarnacao, F.; Carneiro, C.; Dall'Olio, A.

    1990-01-01

    An alternative technique of neutron probe calibration in situ was applied for Podzolic soil. Under field condition, the neutron probe calibration was performed using a special arrangement that prevented the lateral movement of water around the access tube of the neutron probe. During the experiments, successive amounts of water were uniformly infiltrated through the soil profile. Two plots were set to study the effect of the plot dimension on the slope of the calibration curve. The results obtained shown that the amounts of water transferred to the soil profile were significantly correlated to the integrals of count ratio along the soil profile on both plots. In consequence, the slope of calibration curve in field condition was determined. (author)

  14. Limitations of 14 MeV neutron simulation techniques

    Science.gov (United States)

    Kley, W.; Bishop, G. R.; Sinha, A.

    1988-07-01

    A D-T fusion cycle produces five times more neutrons per unit of energy released than a fission cycle, with about twice the damage energy and the capability to produce ten times more hydrogen, helium and transmutation products than fission neutrons. They determine, together with other parameters, the lifetime of the construction materials for the low plasma-density fusion reactors (tokamak, tandem-mirror, etc.), which require a first wall. For the economie feasibility of fusion power reactors the first wall and blanket materials must withstand a dose approaching 300 to 400 dpa. Arguments are presented that demonstrate that today's simulation techniques using existing fission reactors and charged particle beams are excellent tools to study the underlying basic physical phenomena of the evolving damage structures but are not sufficient to provide a valid technological data base for the design of economie fusion power reactors. It is shown than an optimized spallation neutron source based on a continuous beam of 600 MeV, 6 mA protons is suitable to simulate first wall conditions. Comparing it with FMIT the 35 MeV, 100 mA D + -Li neutron source, we arrive at the following figure of merit: FM = {(dpa·volume) EURAC}/{(dpa·volume) FMIT} = {} = 111 reflecting the fact that the proton beam generates about 100 times more neutrons than the deuteron beam in FMIT for the same beam power.

  15. Technique-dependent decrease in thyroid absorbed dose for dental radiography.

    Science.gov (United States)

    Wood, R E; Bristow, R G; Clark, G M; Nussbaum, C; Taylor, K W

    1989-06-01

    A LiF thermoluminescent dosimetry (TLD) system, calibrated in the tissue of interest with the beam used for experimentation, was employed to investigate dosages (muGy) to the thyroid region of an anthropomorphic phantom resultant from two dental complete-mouth radiographic procedures. Both techniques were compared in terms of dosages associated with combinations of lead apron and thyroid collar shielding while using a 70-kVp or 90-kVp x-ray beam for a 20-film complete-mouth series. Lead shielding significantly decreased the dose to the thyroid using both techniques (p less than 0.05). The use of the 90-kVp beam resulted in a significant reduction in the thyroid absorbed dose when using the bisecting angle technique (p less than 0.05) but caused a significant increase in the thyroid absorbed dose when the paralleling technique was used (p less than 0.05). The implementation of higher kilovoltage techniques in dental offices must therefore be dependent on the radiographic technique employed.

  16. Technique-dependent decrease in thyroid absorbed dose for dental radiography

    Energy Technology Data Exchange (ETDEWEB)

    Wood, R.E.; Bristow, R.G.; Clark, G.M.; Nussbaum, C.; Taylor, K.W.

    1989-06-01

    A LiF thermoluminescent dosimetry (TLD) system, calibrated in the tissue of interest with the beam used for experimentation, was employed to investigate dosages (muGy) to the thyroid region of an anthropomorphic phantom resultant from two dental complete-mouth radiographic procedures. Both techniques were compared in terms of dosages associated with combinations of lead apron and thyroid collar shielding while using a 70-kVp or 90-kVp x-ray beam for a 20-film complete-mouth series. Lead shielding significantly decreased the dose to the thyroid using both techniques (p less than 0.05). The use of the 90-kVp beam resulted in a significant reduction in the thyroid absorbed dose when using the bisecting angle technique (p less than 0.05) but caused a significant increase in the thyroid absorbed dose when the paralleling technique was used (p less than 0.05). The implementation of higher kilovoltage techniques in dental offices must therefore be dependent on the radiographic technique employed.

  17. Studies of molecular dynamics with neutron scattering techniques. Part of a coordinated programme on neutron scattering techniques

    International Nuclear Information System (INIS)

    Vinhas, L.A.

    1980-05-01

    Molecular dynamics was studied in samples of tert-butanol, cyclohexanol and methanol, using neutron inelastic and quasi-elastic techniques. The frequency spectra of cyclohexanol in crystalline phase were interpreted by assigning individual energy peaks to hindered rotation of molecules, lattice vibration, hydrogen bond stretching and ring bending modes. Neutron quasi-elastic scattering measurements permitted the testing of models for molecular diffusion as a function of temperature. The interpretation of neutron incoherent inelastic scattering on methanol indicated the different modes of molecular dynamics in this material; individual inelastic peaks in the spectra could be assigned to vibrations of crystalline lattice, stretching of hydrogen bond and vibrational and torsional modes of CH 3 OH molecule. The results of the experimental work on tertbutanol indicate two distinct modes of motion in this material: individual molecular librations are superposed to a cooperative rotation diffusion which occurs both in solid and in liquid state

  18. Characterization of European sword blades through neutron imaging techniques

    Science.gov (United States)

    Salvemini, F.; Grazzi, F.; Peetermans, S.; Gener, M.; Lehmann, E. H.; Zoppi, M.

    2014-09-01

    In the present work, we have studied two European rapier blades, dating back to the period ranging from the Late Renaissance to the Early Modern Age (about 17th to 18th century). In order to determine variation in quality and differences in technology, a study was undertaken with the purpose to observe variations in the blade microstructure (and consequently in the construction processes). The samples, which in the present case were expendable, have been investigated, preliminarily, through standard metallography and then by means of white beam and energy-selective neutron imaging. The comparison of the results, using the two techniques, turned out to be satisfactory, with a substantial quantitative agreement of the results obtained with the two techniques, and show the complementarity of the two methods. Metallography has been considered up to now the method of choice for metal material characterization. The correspondence between the two methods, as well as the non-invasive character of the neutron-based techniques and its possibility to obtain 3D reconstruction, candidate neutron imaging as an important and quantitatively reliable technique for metal characterization.

  19. A study on artificial rare earth (RE2O3) based neutron absorber

    International Nuclear Information System (INIS)

    KIM, Kyung-O; Kyung KIM, Jong

    2015-01-01

    A new concept of a neutron absorption material (i.e., an artificial rare earth compound) was introduced for criticality control in a spent fuel storage system. In particular, spent nuclear fuels were considered as a potential source of rare earth elements because the nuclear fission of uranium produces a full range of nuclides. It was also found that an artificial rare earth compound (RE 2 O 3 ) as a High-Level Waste (HLW) was naturally extracted from pyroprocessing technology developed for recovering uranium and transuranic elements (TRU) from spent fuels. In this study, various characteristics (e.g., activity, neutron absorption cross-section) were analyzed for validating the application possibility of this waste compound as a neutron absorption material. As a result, the artificial rare earth compound had a higher neutron absorption probability in the entire energy range, and it can be used for maintaining sub-criticality for more than 40 years on the basis of the neutron absorption capability of Boral™. Therefore, this approach is expected to vastly improve the efficiency of radioactive waste management by simultaneously keeping HLW and spent nuclear fuel in a restricted space. - Highlights: • Quantitative analysis of rare earth elements in PWR spent fuels. • Extraction of artificial rare earth compound using pyroprocessing technology. • Characteristic analysis of artificial rare earth elements. • Performance evaluation of artificial rare earth for criticality control.

  20. Contribution to the qualification of a calculation schema for PWR reactors involving Gd and Hf neutron absorbers

    International Nuclear Information System (INIS)

    Therond, Patrice.

    1982-06-01

    Hafnium is a material currently used to control plate reactors. It is therefore important to know the degree of accuracy with which its efficiency can be calculated. For reasons, which have little to do with neutronics, it has recently been envisaged to replace this type of control with gadolinium poisons. The interpretation of criticality experiments is the means adopted to qualify these absorbant heterogeneity calculations. Two types of experiment are performed: - For plate lattices, several programs specially developed to test the calculations performed are available; these calculations begin by considering very simple one-dimensional calculations and gradually develop towards realistic two - and three - dimensional configurations. We have interpreted tests of this type realized up until the present day in the framework of such considerations. - In order to complete information obtained in this way, data from experiments performed on a 17 x 17 PWR rod lattice containing the same type of absorbers have been exploited in parallel with these experiments. It has been possible, because of the diversity of the configurations studied, to test most of the codes and calculation options currently used by the CEA for the early life of water reactor lattices, containing hafnium and godolinium absorbant heterogeneities [fr

  1. Analysis of minor phase with neutron diffraction technique

    International Nuclear Information System (INIS)

    Engkir Sukirman; Herry Mugirahardjo

    2014-01-01

    The presence of minor phases in a sample have been analyzed with the neutron diffraction technique. In this research, the sample of Fe nanoparticles (FNP) has been selected as the object of case study. The first step was to prepare the FNP sample with the ball milling technique. Hereinafter, the sample of milling result was referred FIC2. The presence of phases formed in FIC2 were analyzed qualitatively and quantitatively using the high resolution neutron diffraction (HRPD ) and X-Ray Diffraction (XRD) techniques. The diffraction data were analyzed by means of the Rietveld method utilizing a computer code, namely FullProf and performed by referring to the supporting data, namely particle size and magnetic properties of materials. The two kinds of supporting data were obtained from the PSA (Particles Size Analyzer) and VSM (Vibrating Samples Magnetometer), respectively. The analysis result shows that quality of fitting for neutron diffraction pattern is better than the fitting quality for x-ray diffraction pattern. Of the HRPD data were revealed that FIC2 consists of Fe, γFe 2 O 3 and Fe 3 O 4 phases as much as 78.62; 21.37 and 0.01%, respectively. Of the XRD data were obtained that FIC2 consists of Fe and γFe 2 O 3 phases with amount of 99.96 and 0.04%, respectively; the presence of Fe 3 O 4 phase was not observed. With the neutron diffraction technique, the presence of minor phase can be determined accurately. (author)

  2. Advanced neutron diffraction techniques for strain measurements in polycrystalline materials

    OpenAIRE

    Mikula , P.; LukÁs , P.; VrÁna , M.; Klimanek , P.; Kschidock , T.; Macek , K.; Janovec , J.; Osborn , J.; Swallowe , G.

    1993-01-01

    Three unique high resolution experimental arrangements for nondestructive strain measurements which are based on neutron Bragg diffraction optics with cylindrically bent perfect crystals are reviewed. Using focusing in momentum and real space these techniques yield Δd/d (d-lattice spacing) resolution of 10-4 - 10-3 and considerably higher luminosity in comparison with the current dedicated instruments. They permit measurements not only macrostrain components resulting in angular shifts of dif...

  3. Evaluation of neutron irradiation fields for BNCT by using absorbed dose in a phantom

    International Nuclear Information System (INIS)

    Aizawa, O.

    1993-01-01

    In a previous paper, the author defined the open-quotes irradiation timeclose quotes as the time of irradiation in which the maximum open-quotes total background doseclose quotes becomes 2,500 RBE-cGy. In this paper, he has modified the definition a little as the time of irradiation in which the maximum open-quotes lμg/g B-10 doseclose quotes becomes 3,000 RBE-cGy, because he assumed that normal tissue contained 1μg/g B-10. Moreover, he has modified the dose criteria for BNCT as follows: The open-quotes eye doseclose quotes, open-quotes total body doseclose quotes and open-quotes except-head doseclose quotes should be less that 200, 100 and 50 RBE-cGy, respectively. He has added one more criterion for BNCT that the thermal neutron fluence at the tumor position should be over 2.5x10 12 n/cm 2 at the open-quotes irradiation timeclose quotes. The distance from the core side to the irradiation port in the open-quotes old configurationclose quotes of the Musashi reactor (TRIGA-II, 100kW) was 160 cm. He is now planning to design an eccentric core and to move the reactor core nearer to the irradiation port, distance between the core side and the irradiation port to be 140, 130 and 120cm. The other assumptions used in this paper are as follows: (1) The B-10 concentrations in tumor are 30 and/or 10μg/g. (2) The depth of the tumor is 5.0 cm to 5.5 cm from the surface. (3) The RBE values used are 1.0 for all gamma rays and 2.3 for B 10 (n,α) reaction products. (4) The RBE values for neutrons are the following three cases: the first case is using 1.6 for all neutrons; the second one is using 3.2 for non-thermal neutrons and 1.6 for thermal neutrons; the third case is using 4.8 for fast neutrons, 3.2 for faster epithermal and epithermal neutrons, and 1.6 for thermal neutrons

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

    International Nuclear Information System (INIS)

    Youtsos, A.

    2004-01-01

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

  5. An international dosimetry exchange for boron neutron capture therapy, Part I: Absorbed dose measurements

    Czech Academy of Sciences Publication Activity Database

    Binns, P. J.; Riley, K. J.; Harling, O. K.; Kiger III, W. S.; Munck af Rosenschöld, P. M.; Giusti, V.; Capala, J.; Sköld, K.; Auterinen, I.; Serén, T.; Kotiluoto, P.; Uusi-Simola, J.; Marek, M.; Viererbl, L.; Spurný, František

    2005-01-01

    Roč. 32, č. 12 (2005), s. 3729-3736 ISSN 0094-2405 R&D Projects: GA ČR GA202/04/0795 Institutional research plan: CEZ:AV0Z10480505 Keywords : BNCT * thermal neutrons * dosimetry intercomparison Subject RIV: BO - Biophysics Impact factor: 3.192, year: 2005

  6. Neutron Filter Technique and its use for Fundamental and applied Investigations

    International Nuclear Information System (INIS)

    Gritzay, V.; Kolotyi, V.

    2008-01-01

    At Kyiv Research Reactor (KRR) the neutron filtered beam technique is used for more than 30 years and its development continues, the new and updated facilities for neutron cross section measurements provide the receipt of neutron cross sections with rather high accuracy: total neutron cross sections with accuracy 1% and better, neutron scattering cross sections with 3-6% accuracy. The main purpose of this paper is presentation of the neutron measurement techniques, developed at KRR, and demonstration some experimental results, obtained using these techniques

  7. Image reconstruction technique using projection data from neutron tomography system

    Directory of Open Access Journals (Sweden)

    Waleed Abd el Bar

    2015-12-01

    Full Text Available Neutron tomography is a very powerful technique for nondestructive evaluation of heavy industrial components as well as for soft hydrogenous materials enclosed in heavy metals which are usually difficult to image using X-rays. Due to the properties of the image acquisition system, the projection images are distorted by several artifacts, and these reduce the quality of the reconstruction. In order to eliminate these harmful effects the projection images should be corrected before reconstruction. This paper gives a description of a filter back projection (FBP technique, which is used for reconstruction of projected data obtained from transmission measurements by neutron tomography system We demonstrated the use of spatial Discrete Fourier Transform (DFT and the 2D Inverse DFT in the formulation of the method, and outlined the theory of reconstruction of a 2D neutron image from a sequence of 1D projections taken at different angles between 0 and π in MATLAB environment. Projections are generated by applying the Radon transform to the original image at different angles.

  8. Understanding and predicting the behaviour of silver base neutron absorbers under irradiations; Comprehension et prediction du comportement sous irradiation neutronique d`alliages absorbants a base d`argent

    Energy Technology Data Exchange (ETDEWEB)

    Desgranges, C

    1998-12-31

    The effect of neutron irradiation induced transmutations on the swelling of AgInCd (AIC) alloys used as neutron absorber in the control rods of Pressurized Water Reactors has been studied both experimentally and theoretically. Effective atomic volumes have been determined in synthetic AgCdInSn alloys with various compositions and containing fcc and hc phases, representative of irradiated AIC (Sn is a transmutation product). Swelling is shown to result first from the transmutation of Ag into Cd and of In into Sn, both with larger effective volume than the mother atom, and second from grain boundaries precipitation of s still less dense hc phase when solid solubility of transmuted products is exceeded. For both fcc and hc phases, we have determined profiles at the temperatures in the vicinity of the operating temperature. Unusual characteristics of second phase growth at grain boundaries induced by transmutations are identified on a simple binary alloy model: kinetics is controlled by irradiation temperature which scales diffusivities and flux which scales transmutation rates, as well as by the grain size in the underlying matrix. To address the AgInCdSn alloys, a novel technique is proposed to model diffusion in multicomponent alloys. It is based on a linearization of a simple atomistic model. With a single set of parameters, for each phase, our model well reproduces our interdiffusion measurements in quaternary alloys as well as existing interdiffusion experiments in binary alloys. Finally this diffusion model implemented with a moving interface algorithm is used to model the growth of the second phase induced by transmutation in the AIC under irradiation. (authors) 74 refs.

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

    Science.gov (United States)

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

    2013-09-01

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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  11. New laser technique revives old ideas for thermoluminescence neutron dosimetry

    International Nuclear Information System (INIS)

    Braeunlich, P.; Brown, M.; Gasiot, J.; Fillard, J.P.

    1982-01-01

    Laser heating is discussed as a means to evaluate thermoluminescence dosimeters in neutron dosimetry. Direct energy coupling from the photon beam to the phonons of the TL material permits heating of thin layers with rates of temperature increase exceeding 10 4 Ks - 1 . Rapid TLD evaluation will allow the design of dosimetry badges containing a number of different small thin film TLD elements in various orientations and behind appropriate filters, hydrogenous radiators, etc. Desired redundance is readily possible by using back-up TLDs for every specific task. Reading occurs with a scanning laser beam rather than by mechanically manipulating the TLD toward a fixed heat source. Improvements in the signal-to-noise ratio of up to a factor of 1000 are readily obtained. Thus, sensitive thin-film TLDs can be designed with negligible self-shielding for thermal neutrons in albedo applications and with known, nearly energy dependent cavity correction factors for dosimetry in mixed n-#betta# fields. Due to the greatly increased sensitivity possible with fast laser heating, significant advances are expected in the fast neutron dosimetry techniques which are based on hydrogeneous proton radiators or LET-dependent slow peak formation

  12. Error reduction techniques for Monte Carlo neutron transport calculations

    International Nuclear Information System (INIS)

    Ju, J.H.W.

    1981-01-01

    Monte Carlo methods have been widely applied to problems in nuclear physics, mathematical reliability, communication theory, and other areas. The work in this thesis is developed mainly with neutron transport applications in mind. For nuclear reactor and many other applications, random walk processes have been used to estimate multi-dimensional integrals and obtain information about the solution of integral equations. When the analysis is statistically based such calculations are often costly, and the development of efficient estimation techniques plays a critical role in these applications. All of the error reduction techniques developed in this work are applied to model problems. It is found that the nearly optimal parameters selected by the analytic method for use with GWAN estimator are nearly identical to parameters selected by the multistage method. Modified path length estimation (based on the path length importance measure) leads to excellent error reduction in all model problems examined. Finally, it should be pointed out that techniques used for neutron transport problems may be transferred easily to other application areas which are based on random walk processes. The transport problems studied in this dissertation provide exceptionally severe tests of the error reduction potential of any sampling procedure. It is therefore expected that the methods of this dissertation will prove useful in many other application areas

  13. Advanced neutron diffraction techniques for strain measurements in polycrystalline materials

    International Nuclear Information System (INIS)

    Mikula, P.; Lukas, P.; Vrana, M.; Klimanek, P.; Kschidock, T.; Macek, K.; Janovec, J.; Osborn, J.C.; Swallowe, G.M.

    1993-01-01

    Three unique high resolution experimental arrangements for nondestructive strain measurements which are based on neutron Bragg diffraction optics with cylindrically bent perfect crystals are reviewed. Using focusing in momentum and real space these techniques yield Δd/d (d-lattice spacing) resolution of 10 -4 - 10 -3 and considerably higher luminosity in comparison with the current dedicated instruments. They permit measurements not only macrostrain components resulting in angular shifts of diffraction peaks but also of microstrains by means of profile-broadening analysis. (orig.)

  14. Neutron multiplicity equation and its application for (n,2n) multiplication measurements by statistical correlation techniques

    International Nuclear Information System (INIS)

    Kumar, A.; Srinivasan, M.

    1986-01-01

    A new equation, called the neutron multiplicity equation (NME), has been derived starting from basic physics principles. Neutron multiplicity v is defined as the integral number of neutrons leaking from a neutron multiplying system for a source neutron introduced into it. Probability distribution of neutron multiplicities (PDNMs) gives the probability of leakage of neutrons as a function of their multiplicity v. The PDNM is directly measurable through statistical correlation techniques. In a specific application, the NME has been solved for PDNM as a function of v for /sup 9/Be spheres of varying radii and driven by a centrally located 14-MeV deuterium-tritium neutron source. The potential of NME for sensitivity analysis is demonstrated through a particular modification of secondary neutron transfer cross sections of /sup 9/Be. It turns out that PDNM is very sensitive, even as the ''average'' neutron leakage is practically insensitive to it

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

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

  16. Study of neutron absorbing microspheres in research reactors - Metal systems wear

    International Nuclear Information System (INIS)

    Gana Watkins, Ignacio A.; Silin, Nicolas; Prado, Miguel O.; Mazufri, Claudio

    2012-01-01

    Now-a-days, it is increasingly common for nuclear power plants, as well as research reactors, to be designed and built with an alternative safety system aside from control rods. The acids and/or salts in solution injection systems is most frequently used. However, these systems present several implementation and operation problems due to the physical and chemical properties of the used compounds. After analyzing these drawbacks, we developed a new alternative safety system that contains the absorbing element isolated from the aqueous medium. In this context, it's proposed the use of aluminum borosilicate microspheres. The current paper presents erosion wear experiments to determine under which conditions microspheres can be considered as a potential component of a secondary shut down system in a nuclear facility (author))

  17. Neutron flux characterization of californium-252 Neutron Research Facility at the University of Texas - Pan American by nuclear analytical technique

    Science.gov (United States)

    Wahid, Kareem; Sanchez, Patrick; Hannan, Mohammad

    2014-03-01

    In the field of nuclear science, neutron flux is an intrinsic property of nuclear reaction facilities that is the basis for experimental irradiation calculations and analysis. In the Rio Grande Valley (Texas), the UTPA Neutron Research Facility (NRF) is currently the only neutron facility available for experimental research purposes. The facility is comprised of a 20-microgram californium-252 neutron source surrounded by a shielding cascade containing different irradiation cavities. Thermal and fast neutron flux values for the UTPA NRF have yet to be fully investigated and may be of particular interest to biomedical studies in low neutron dose applications. Though a variety of techniques exist for the characterization of neutron flux, neutron activation analysis (NAA) of metal and nonmetal foils is a commonly utilized experimental method because of its detection sensitivity and availability. The aim of our current investigation is to employ foil activation in the determination of neutron flux values for the UTPA NSRF for further research purposes. Neutron spectrum unfolding of the acquired experimental data via specialized software and subsequent comparison for consistency with computational models lends confidence to the results.

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

    International Nuclear Information System (INIS)

    Aquirre O, G.A.

    1978-01-01

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

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

    International Nuclear Information System (INIS)

    Chimoye, T.; Fuangfoong, M.

    1998-01-01

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

  20. Radiation shielding material characterization by non-destructive neutron radiography technique

    International Nuclear Information System (INIS)

    Hafizal Yazid; Azali Muhammad; Abdul Aziz Mohamed; Rafhayudi Jamro; Hishamuddin Husain

    2007-01-01

    Shielding property of boronated rubber was characterized easily by the use of neutron radiography technique. For 10 phr of boron carbide in the natural rubber composite, the ability to completely shield against neutron was found to have 8mm thickness and above for the neutron flux of 1.04 x 10 5 n/cm 2 s (author)

  1. Study on bioavailability of dietary iron of women by using activable isotopic tracer and neutron activation analysis techniques

    International Nuclear Information System (INIS)

    Zhang Yangmei; Ni Bangfa; Tian Weizhi; Wang Pingsheng; Cao Lei

    2002-01-01

    The bioavailability of diet iron of 10 healthy young women in Beijing area is studied by using two enriched isotopes 54 Fe and 58 Fe, and neutron activation analysis techniques. The abundance of 54 Fe and 58 Fe is 61.4% and 23.4%, respectively. In additional, the atomic absorption spectrometry is employed to measure total iron in fecal samples. Dysprosium, rarely absorbed by human body, is used to monitor the residence time of tracer isotopes in order to collect the fecal samples completely. The results show that the bioavailability of dietary iron in young women is (14.9 +- 3.9)%

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

    International Nuclear Information System (INIS)

    Krezel, A.; Alabaster, P.; Bakshi, E.; McManus, K.

    1999-01-01

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

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

    CERN Document Server

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

    1999-01-01

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

  4. Morphologic characterization of Mycobacterium marinum by neutron radiographic technique

    International Nuclear Information System (INIS)

    Silva, Jaqueline Michele da; Crispim, Verginia Reis; Silva, Marlei Gomes da

    2011-01-01

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

  5. Morphologic characterization of Mycobacterium marinum by neutron radiographic technique

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

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

  6. 3-D Deep Penetration Neutron Imaging of Thick Absorbing and Diffusive Objects Using Transport Theory. Final technical report

    International Nuclear Information System (INIS)

    Ragusa, Jean; Bangerth, Wolfgang

    2011-01-01

    here explores the inverse problem of optical tomography applied to heterogeneous domains. The neutral particle transport equation was used as the forward model for how neutral particles stream through and interact within these heterogeneous domains. A constrained optimization technique that uses Newtons method served as the basis of the inverse problem. Optical tomography aims at reconstructing the material properties using (a) illuminating sources and (b) detector readings. However, accurate simulations for radiation transport require that the particle (gamma and/or neutron) energy be appropriate discretize in the multigroup approximation. This, in turns, yields optical tomography problems where the number of unknowns grows (1) about quadratically with respect to the number of energy groups, G, (notably to reconstruct the scattering matrix) and (2) linearly with respect to the number of unknown material regions. As pointed out, a promising approach could rely on algorithms to appropriately select a material type per material zone rather than G2 values. This approach, though promising, still requires further investigation: (a) when switching from cross-section values unknowns to material type indices (discrete integer unknowns), integer programming techniques are needed since derivative information is no longer available; and (b) the issue of selecting the initial material zoning remains. The work reported here proposes an approach to solve the latter item, whereby a material zoning is proposed using one-group or few-groups transport approximations. The capabilities and limitations of the presented method were explored; they are briefly summarized next and later described in fuller details in the Appendices. The major factors that influenced the ability of the optimization method to reconstruct the cross sections of these domains included the locations of the sources used to illuminate the domains, the number of separate experiments used in the reconstruction, the

  7. Characterization of the neutron sources storage pool of the Neutron Standards Laboratory, using Montecarlo Techniques

    International Nuclear Information System (INIS)

    Campo Blanco, X.

    2015-01-01

    The development of irradiation damage resistant materials is one of the most important open fields in the design of experimental facilities and conceptual nucleoelectric fusion plants. The Neutron Standards Laboratory aims to contribute to this development by allowing the neutron irradiation of materials in its calibration neutron sources storage pool. For this purposes, it is essential to characterize the pool itself in terms of neutron fluence and spectra due to the calibration neutron sources. In this work, the main features of this facility are presented and the characterization of the storage pool is carried out. Finally, an application is shown of the obtained results to the neutron irradiation of material.

  8. Qualitative texture investigation of a maraging steel sample by neutron diffraction technique

    International Nuclear Information System (INIS)

    Pugliesi, R.; Yamazaki, I.M.

    1988-08-01

    By means of the neutron diffraction technique the texture of a maraging steel rolled sheet have been determined. The measurements were performed by using a neutron diffractometer installed at the IEA-PI Nuclear Research Reactor, in the beam-hole n 0 6. To avoid corrections such as neutron absorption and sample luminosity the geometric form of the sample was approximated to spheric and its dimensions do not exceed that of neutron beam. The texture of the sample was analysed with help of a computer programm that analyses the intensity of the diffracted neutron beam and plot the pole figure. (author) [pt

  9. Pulsed-neutron techniques for condensed-matter research

    Energy Technology Data Exchange (ETDEWEB)

    Brown, B.S.; Carpenter, J.M.; Jorgensen, J.D.; Price, D.L.; Kamitakahara, W.

    1981-01-01

    Pulsed spallation sources are reviewed in a historical content as the latest generation of neutron sources in a line that started with the discovery of the neutron in 1932 and proceeded through research-reactor and accelerator-driven sources. The characteristics of the spallation sources are discussed in relation to their capabilities for structural and dynamical studies of condensed matter with slow neutrons and radiation effects research with fast neutrons. The new scientific opportunities opened up in these fields by the unique features of the sources are briefly reviewed, with some examples of completed work and experiments being planned.

  10. Small-angle neutron scattering technique in liquid crystal studies

    International Nuclear Information System (INIS)

    Shahidan Radiman

    2005-01-01

    The following topics discussed: general principles of SAS (Small-angle Neutron Scattering), liquid crystals, nanoparticle templating on liquid crystals, examples of SAS results, prospects of this studies

  11. Determination of spallation neutron flux through spectral adjustment techniques

    Science.gov (United States)

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

    2016-08-01

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

  12. Determination of spallation neutron flux through spectral adjustment techniques

    Energy Technology Data Exchange (ETDEWEB)

    Mosby, M.A., E-mail: mosbym@lanl.gov; Engle, J.W.; Jackman, K.R.; Nortier, F.M.; Birnbaum, E.R.

    2016-08-15

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

  13. The recent development of neutronic techniques for determination of residual stresses

    International Nuclear Information System (INIS)

    Lodini, A.

    2001-01-01

    Neutron diffraction is a well-established non-destructive method for the measurement of residual stress deep inside materials. This paper gives a short overview of the use of neutrons for materials research and measurement techniques. Neutron diffraction has been applied in determining residual stresses in metal matrix composites. Measurement and prediction of residual stress for plastic deformation are presented. More recently, the neutron diffraction technique has also been applied for the determination of plastic strain which results from microstructural defects and leads to peak broadening. Influence of the shot penning treatment on austenitic steel is presented. (author)

  14. Radiolysis of some aqueous solutions of neutron absorbers; Etude des effets de certains absorbeurs de neutrons en solution sur la radiolyse de l'eau

    Energy Technology Data Exchange (ETDEWEB)

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

    1964-12-15

    The initial yield of molecular hydrogen formed by radiolytic decomposition of water in reactor and {sup 60}Co gamma radiation is decreased by the presence of salts of polyvalent elements possessing only one stable valence, i.e cadmium, zinc, magnesium, gadolinium. This effect is favourable for the use of cadmium and gadolinium as soluble neutron absorber in heavy water reactors. Cations of these salts are not inert toward the primary products of water radiolysis. They have a high degree of reactivity toward the hydrated electron, which is the precursor of molecular hydrogen in neutral or alkaline aqueous media. The value of the rate constant for the reaction between cadmium ion and hydrated electron was shown to be (6.1 {+-} 1.8) 10{sup 10} M{sup -1} s{sup -1}. Boric acid at low concentration has no effect on the radiation chemistry of water. An isotope effect has been found in the radiolysis of heavy water, corresponding to a lowering of initial yield [G{sub 0}(D{sub 2}) < G{sub 0}(H{sub 2})]. additionally it was necessary to determine the influence of organic impurities, remaining after the purification of water, on the mechanism of its radiolytic decomposition. (author) [French] Le rendement initial de la formation d'hydrogene moleculaire dans la decomposition radiolytique de l'eau, sous l'effet du rayonnement des reacteurs nucleaires ou du cobalt 60, est diminue si le solute est un sel d'element polyvalent ne possedant qu'un seul etat stable de valence (cadmium, zinc, magnesium, gadolinium). Cet effet est favorable au choix des elements cadmium et gadolinium pour servir d'absorbeur soluble de neutrons dans un reacteur a eau lourde. Les cations de ces sels ne sont pas inertes vis-a-vis des produits primaires de la radiolyse. Ils ont une affinite notable pour l'electron solvate, precurseur de l'hydrogene moleculaire en milieu neutre ou alcalin. En particulier, la constante de vitesse de la reaction du cadmium ionise avec l

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

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

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

  16. Fabrication and characterisation of selective solar absorber surfaces prepared by sol-gel technique

    CSIR Research Space (South Africa)

    Katumba, G

    2006-07-01

    Full Text Available The investigation and development of carbon-silica composites has been going on for some time. Different applications such as adsorbents, biosensors, templates and solar absorbers have emanated from these studies. The concept of using solar...

  17. A technique for determining the deuterium/hydrogen contrast map in neutron macromolecular crystallography.

    Science.gov (United States)

    Chatake, Toshiyuki; Fujiwara, Satoru

    2016-01-01

    A difference in the neutron scattering length between hydrogen and deuterium leads to a high density contrast in neutron Fourier maps. In this study, a technique for determining the deuterium/hydrogen (D/H) contrast map in neutron macromolecular crystallography is developed and evaluated using ribonuclease A. The contrast map between the D2O-solvent and H2O-solvent crystals is calculated in real space, rather than in reciprocal space as performed in previous neutron D/H contrast crystallography. The present technique can thus utilize all of the amplitudes of the neutron structure factors for both D2O-solvent and H2O-solvent crystals. The neutron D/H contrast maps clearly demonstrate the powerful detectability of H/D exchange in proteins. In fact, alternative protonation states and alternative conformations of hydroxyl groups are observed at medium resolution (1.8 Å). Moreover, water molecules can be categorized into three types according to their tendency towards rotational disorder. These results directly indicate improvement in the neutron crystal structure analysis. This technique is suitable for incorporation into the standard structure-determination process used in neutron protein crystallography; consequently, more precise and efficient determination of the D-atom positions is possible using a combination of this D/H contrast technique and standard neutron structure-determination protocols.

  18. Designing on-line analyzer for coal on belt conveyor using neutron activation technique

    International Nuclear Information System (INIS)

    Rony Djokorayono; Agus Cahyono

    2014-01-01

    Basic design of on-line analyzer for coal on belt conveyor using neutron activation technique has been carried out. Compared with sampling technique, this neutron activation technique has some advantages in term of analysis accuracy and time. The design activities performed include the establishment of design requirements, functional requirements, technical requirements, technical specification, detection sub-system design, data acquisition subsystem design, and operator computer console design. This program will use Nal(Tl) scintillation detector to detect gamma-rays emitted by elements in coal due to neutron activation of a neutron source, 252 Cf (Californium-252). This basic design of on-line analyzer for coal on belt conveyor using neutron activation technique should be followed up with the development of detailed design, prototype construction, and field testing. (author)

  19. Dirhenium decacarbonyl-loaded PLLA nanoparticles: influence of neutron irradiation and preliminary in vivo administration by the TMT technique.

    Science.gov (United States)

    Hamoudeh, Misara; Fessi, Hatem; Mehier, Henri; Faraj, Achraf Al; Canet-Soulas, Emmanuelle

    2008-02-04

    neutron irradiation, yielding an absorbed dose of 450kGy, can be a terminal method for nanoparticles sterilisation. Thereafter, in a preliminary in vivo experiment, superparamagnetic non radioactive nanoparticles loaded with Re(2)(CO)(10) and oleic-acid coated magnetite have been successfully injected into a mice animal model via targeted multi therapy (TMT) technique which would be our selected administration method for future in vivo studies. In conclusion, although some induced neutron irradiation damage to nanoparticles occurs, dirhenium decacarbonyl-loaded PLLA nanoparticles retain their chemical identity and remain almost as re-dispersible and injectable nanoparticles by the TMT technique. These nanoparticles represent a novel interesting candidate for local intra-tumoral radiotherapy.

  20. Degradation analysis of neutrons absorber bars Ag-In-Cd. Part 1: alloy depletion, neutrons absorption effectiveness and mechanical properties; Analise da degradacao de barras absorvedoras de neutrons de Ag-In.Cd. Parte 1: deplecao da liga, efetividade de absorcao de neutrons e propriedades mecanicas

    Energy Technology Data Exchange (ETDEWEB)

    Castanheira, Myrthes; Terremoto, Luis Antonio A.; Silva, Jose Eduardo Rosa da; Zeituni, Carlos Alberto [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Centro de Engenharia Nuclear

    2002-07-01

    The original alloy of IEA-R1 reactor absorber bars (supposing similar to alloy 2533 with composition 81,5% Ag - 136% In -4,9% Cd) was designed to work for a life time equivalent to a neutron exposition of {approx}10{sup 21} n/cm{sup 2} (thermal) so that the alloy can preserve the characteristic one phase. Analyzing the behavior of absorber bars Ag-In-Cd under irradiation, this work reports a semi quantitative assessment of the IEA-R1 absorber bars degradation current condition by viewpoint of alloy depletion, neutrons absorption effectiveness and mechanical properties, as a complement of visual inspections results carried out at 1998, 2000 and 2001 whose had pointed to visible degree of degradation accumulated along 29 years of operation in the reactor. (author)

  1. Burnable neutron absorbers

    International Nuclear Information System (INIS)

    Radford, K.C.; Carlson, W.G.

    1985-01-01

    This invention provides ceramic processing including sintering schedules which produce annular pellets containing burnable poisons for use in reactor control rods. Typically the powder includes Al 2 O 3 and from 1 to 50 weight percent B 4 C. The Al 2 O 3 and B 4 C, appropriately sized, are milled in a ball mill with liquid to produce a slurry. The slurry is spray dried to produce small spheres of the mixed powder, which is mixed with adequate organic binder and plasticizer and formed into a hollow green body having the shape of a tube. The green body is sintered to produce a ceramic tube from which the pellets are cut. The tube is sintered to size so that the pellets have the required dimensions. It is an important feature of this invention that the powder is formed into the green body by applying isostatic pressure to the powder

  2. TLD-300 detectors for separate measurement of total and gamma absorbed dose distributions of single, multiple, and moving-field neutron treatments

    International Nuclear Information System (INIS)

    Rassow, J.

    1984-01-01

    Fast neutron therapy requirements, because of the poor depth dose characteristic of present therapeutical sources, are at least as complex in treatment plans as photon therapy. The physical part of the treatment planning is very important; however, it is much more complicated than for photons or electrons owing to the need for: Separation of total and gamma absorbed dose distributions (Dsub(T) and Dsub(G)); and more stringent tissue-equivalence conditions of phantoms than in photon therapy. Therefore, methods of clinical dosimetry for the separate determination of total and gamma absorbed dose distributions in irregularly shaped (inhomogeneous) phantoms are needed. A method using TLD-300 (CaF 2 :Tm) detectors is described, which is able to give an approximate solution of the above-mentioned dosimetric requirements. The two independent doses, Dsub(T) and Dsub(G), can be calculated by an on-line computer analysis of the digitalized glow curve of TLD-300 detectors, irradiated with d(14)+Be neutrons of the cyclotron isocentric neutron therapy facility CIRCE in Essen. Results are presented for depth and lateral absorbed dose distributions (Dsub(T) and Dsub(G)) for fixed neutron beams of different field sizes compared with measurements by standard procedures (TE-TE ionization chamber, GM counter) in an A-150 phantom. The TLD-300 results for multiple and moving-field treatments (with and without wedge filters) in a patient simulating irregularly shaped (inhomogeneous) phantoms, are shown together with computer calculations of these dose distributions. The probable causes for some systematic deviations are discussed, which lead to open problems for further investigations owing to features of the detector material and the evaluation method, but mainly to differences in the composition of phantom materials used for the calculations (standard dose distributions) and TLD-300 measurements. (author)

  3. Neutron Spectroscopy for pulsed beams with frame overlap using a double time-of-flight technique

    Science.gov (United States)

    Harrig, K. P.; Goldblum, B. L.; Brown, J. A.; Bleuel, D. L.; Bernstein, L. A.; Bevins, J.; Harasty, M.; Laplace, T. A.; Matthews, E. F.

    2018-01-01

    A new double time-of-flight (dTOF) neutron spectroscopy technique has been developed for pulsed broad spectrum sources with a duty cycle that results in frame overlap, where fast neutrons from a given pulse overtake slower neutrons from previous pulses. Using a tunable beam at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory, neutrons were produced via thick-target breakup of 16 MeV deuterons on a beryllium target in the cyclotron vault. The breakup spectral shape was deduced from a dTOF measurement using an array of EJ-309 organic liquid scintillators. Simulation of the neutron detection efficiency of the scintillator array was performed using both GEANT4 and MCNP6. The efficiency-corrected spectral shape was normalized using a foil activation technique to obtain the energy-dependent flux of the neutron beam at zero degrees with respect to the incoming deuteron beam. The dTOF neutron spectrum was compared to spectra obtained using HEPROW and GRAVEL pulse height spectrum unfolding techniques. While the unfolding and dTOF results exhibit some discrepancies in shape, the integrated flux values agree within two standard deviations. This method obviates neutron time-of-flight spectroscopy challenges posed by pulsed beams with frame overlap and opens new opportunities for pulsed white neutron source facilities.

  4. The new generations of power components will depend on neutron and/or electron bombardment techniques

    International Nuclear Information System (INIS)

    Lilen, H.

    1976-01-01

    Neutron and electron bombardment techniques for materials doping, newly introduced in the fabrication of power semiconductor components: diodes, transistors, thyristors, and triacs are briefly outlined. A neutron bombardment of high purity silicon results in a short-lived 31 Si isotope (from 30 Si) decaying into 31 P. The phosphorus with its five peripheral electrons induces a negative doping (N), and the neutron technique gives a homogeneous doping. Furthermore, silicon bombardment with 1 to 2MeV electrons induces micro-ruptures in the lattice, that act as recombination traps reducing carrier lifetimes. Consequently, gold diffusion techniques can be replaced by electron bombardment with a gain in controlling carrier lifetimes [fr

  5. Observation and modeling of biological colloids with neutron scattering techniques and Monte Carlo simulations

    NARCIS (Netherlands)

    Van Heijkamp, L.F.

    2011-01-01

    In this study non-invasive neutron scattering techniques are used on soft condensed matter, probing colloidal length scales. Neutrons penetrate deeply into matter and have a different interaction with hydrogen and deuterium, allowing for tunable contrast using light and heavy water as solvents. The

  6. Absorbed dose to water determination with ionization chamber dosimetry and calorimetry in restricted neutron, photon, proton and heavy-ion radiation fields.

    Science.gov (United States)

    Brede, H J; Greif, K-D; Hecker, O; Heeg, P; Heese, J; Jones, D T L; Kluge, H; Schardt, D

    2006-08-07

    Absolute dose measurements with a transportable water calorimeter and ionization chambers were performed at a water depth of 20 mm in four different types of radiation fields, for a collimated (60)Co photon beam, for a collimated neutron beam with a fluence-averaged mean energy of 5.25 MeV, for collimated proton beams with mean energies of 36 MeV and 182 MeV at the measuring position, and for a (12)C ion beam in a scanned mode with an energy per atomic mass of 430 MeV u(-1). The ionization chambers actually used were calibrated in units of air kerma in the photon reference field of the PTB and in units of absorbed dose to water for a Farmer-type chamber at GSI. The absorbed dose to water inferred from calorimetry was compared with the dose derived from ionometry by applying the radiation-field-dependent parameters. For neutrons, the quantities of the ICRU Report 45, for protons the quantities of the ICRU Report 59 and for the (12)C ion beam, the recommended values of the International Atomic Energy Agency (IAEA) protocol (TRS 398) were applied. The mean values of the absolute absorbed dose to water obtained with these two independent methods agreed within the standard uncertainty (k = 1) of 1.8% for calorimetry and of 3.0% for ionometry for all types and energies of the radiation beams used in this comparison.

  7. The neutron spin-echo spectrometer: a new high resolution technique in neutron scattering

    International Nuclear Information System (INIS)

    Nicholson, L.K.

    1981-01-01

    The neutron spin-echo (NSE) spectrometer provides the highest energy resolution available in neutron scattering experiments. The article describes the principles behind the first NSE spectrometer (at the Institute Laue-Langevin, Grenoble, France) and, as an example of one of its applications, some recent results on polymer chain dynamics are presented. (author)

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

    International Nuclear Information System (INIS)

    Matsubayashi, Masahito

    1999-01-01

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

  9. Electron-volt spectroscopy at a pulsed neutron source using a resonance detector technique

    CERN Document Server

    Andreani, C; Senesi, R; Gorini, G; Tardocchi, M; Bracco, A; Rhodes, N; Schooneveld, E M

    2002-01-01

    The effectiveness of the neutron resonance detector spectrometer for deep inelastic neutron scattering measurements has been assessed by measuring the Pb scattering on the eVS spectrometer at ISIS pulsed neutron source and natural U foils as (n,gamma) resonance converters. A conventional NaI scintillator with massive shielding has been used as gamma detector. A neutron energy window up to 90 eV, including four distinct resonance peaks, has been assessed. A net decrease of the intrinsic width of the 6.6 eV resonance peak has also been demonstrated employing the double difference spectrum technique, with two uranium foils of different thickness.

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

    CERN Document Server

    Kiraly, B; Csikai, J

    2001-01-01

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

  11. Neutron dose measurements in PET medical cyclotron by foil activation technique

    International Nuclear Information System (INIS)

    Deepa, S.; Sathian, V.; Phadnis, U.V.; Pal, Rupali; Jayalakshmi, V.; Chaurasiya, G.; Kannan, S.; Soni, P.S.

    2007-01-01

    Radionuclides are being used in diagnostic purpose as well as therapeutic purpose under medical category for early detection of malignancies, the diagnosis using radionuclides are playing very important role. PET scan is a miles stone in medical history. These scan is done using a positron emitter 18 F. This radionuclide is produced by the reaction 18 O (p, n) 18 F. In RMC this is produced using accelerated proton using cyclotron. The neutron production is an unwanted by product. These neutrons will make lot of radiation protection problem as neutron itself and also these neutrons will produce induced activity in the different elements of cyclotron shielding material as well as the wall materials in long run. So the accurate neutron dose measurement is very important. The measurement of neutron dose in cyclotron of RMC using activation foil technique is presented in this paper

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

    International Nuclear Information System (INIS)

    Mukherjee, Bhaskar

    2002-01-01

    The Bonner sphere spectrometers (BSS) are commonly used to determine the neutron spectra within various nuclear facilities. Sophisticated mathematical tools are used to unfold the neutron energy distribution from the output data of the BSS. This paper highlights a novel high-resolution neutron spectra-unfolding method using the Genetic Algorithm (GA) technique. The GA imitates the biological evolution process prevailing in the nature to solve complex optimisation problems. The GA method was utilised to evaluate the neutron energy distribution, average energy, fluence and equivalent dose rates at important work places of a DIDO class research reactor and a high-energy superconducting heavy ion cyclotron. The spectrometer was calibrated with a 241 Am/Be (α,n) neutron standard source. The results of the GA method agreed satisfactorily with the results obtained by using the well-known BUNKI neutron spectra unfolding code

  13. SU-E-T-108: 3D Measurement of Neutron Dose from a Novel Neutron Imaging Technique.

    Science.gov (United States)

    Kapadia, A; Crowell, A; Fallin, B; Howell, C; Agasthya, G; Lakshmanan, M; Newton, J; Juang, T; Oldham, M

    2012-06-01

    We have been developing a fast-neutron spectroscopic technique to quantitatively image the distribution of elements in the body using quasi-monochromatic neutron beams. Previously, we demonstrated the ability of the technique to quantify specific elements in the liver and breast while limiting radiation dose to clinically acceptable levels. Here we present the results of a physical dose measurement performed through neutron irradiation of 3D PRESAGE dosimetry phantoms. Two PRESAGE optical-CT dosimeters were placed inside a physical phantom of the human torso and irradiated with 8 MeV neutrons produced via the 2H(d,n) reaction using a tandem Van-de-Graaff accelerator. The dosimeters, measuring 10 cm and 4 cm in diameter, were located in regions corresponding to the liver (10 cm), and the kidney (4 cm). Irradiation was performed with the neutron beam incident directly on the larger dosimeter. Cumulative neutron fluence incident upon each dosimeter was determined using an aluminum-foil activation technique. Following irradiation, the change in optical density in both dosimeters was measured to determine the relative irradiation and dose distribution in each volume. Both PRESAGE dosimeters exhibited detectable changes in optical density corresponding to the dose deposited in the volume. The two dosimeters registered doses of 8.5 Gy (direct incidence, 4.5 hour irradiation) and 0.25 Gy (off-axis, 20 hour irradiation), respectively. The larger dosimeter showed highest intensity at the entry point of the beam with exponential drop-off along the beam direction. The smaller dosimeter registered a more uniform change in intensity, consistent with the higher incidence of scattered neutrons at this location. The results demonstrate the utility of PRESAGE dosimeters in measuring dose from neutron irradiation and highlight the difference in relative doses between primary and proximal organs when exposed to neutron beams. This work was supported by the United States Department of

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

    Directory of Open Access Journals (Sweden)

    Michel Thellier

    2006-01-01

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

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

    OpenAIRE

    Thellier, Michel; Ripoll, Camille

    2006-01-01

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

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

    International Nuclear Information System (INIS)

    Loria, L. G.; Jimenez, R.; Thellier, M.

    1999-01-01

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

  17. Diffraction by the time-of-flight technique at pulsed neutron sources

    International Nuclear Information System (INIS)

    Jorgensen, J.D.

    1984-06-01

    The recent development of accelerator-based pulsed neutron sources as an alternative to reactor sources has caused a renewed interest in time-of-flight neutron diffraction techniques because the time-of-flight method can be optimally used at pulsed sources. Since neutrons have finite mass, and therefore travel at a velocity proportional to their wavelength, neutron diffraction can be done either by the conventional technique commonly used for X-rays, where a single wavelength is used, or by the time-of-flight technique, where all wavelengths are used. In a conventional diffraction experiment with monochromatic radiation, the Bragg equation d = lambda/(2 sin theta) is satisfied by varying the angle 2 theta at which the scattered radiation is detected. In a time-of-flight diffraction experiment, all wavelengths lambda are allowed to scatter from the sample and are determined by recording the times at which neutrons arrive at a detector in a fixed position. Neutron diffraction has been done by the time-of-flight technique for many years using mechanical neutron choppers at reactor sources, but found only limited application because the chopper instruments could not be properly optimized with respect to beam size, pulse width, and repetition rate. The new accelerator-based pulsed neutron sources produce neutrons in short, intense bursts, eliminating the need for mechanical choppers. The pulse width and repetition rate can be tailored to meet the requirements of a particular instrument. After only a few years of development, this has allowed time-of-flight diffraction instruments at moderately-sized pulsed neutron sources

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

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Sang-Jin [Korea Atomic Energy Reserch Institute, 150 Deokjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Seung, Baek-Soek [Korea Atomic Energy Reserch Institute, 150 Deokjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Lee, Chang-Hee [Korea Atomic Energy Reserch Institute, 150 Deokjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Kim, Hark-Rho [Korea Atomic Energy Reserch Institute, 150 Deokjin-dong, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)

    2006-11-15

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

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

    International Nuclear Information System (INIS)

    Avdic, Senada

    2000-09-01

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

  20. Evaluation of spectral unfolding techniques for neutron spectroscopy

    International Nuclear Information System (INIS)

    Sunden, Erik Andersson; Conroy, S.; Ericsson, G.; Johnson, M. Gatu; Giacomelli, L.; Hellesen, C.; Hjalmarsson, A.; Ronchi, E.; Sjoestrand, H.; Weiszflog, M.; Kaellne, J.; Gorini, G.; Tardocchi, M.

    2008-01-01

    The precision of the JET installations of MAXED, GRAVEL and the L-curve version of MAXED has been evaluated by using synthetic neutron spectra. We have determined the number of counts needed for the detector systems NE213 and MPR to get an error below 10% of the MAXED unfolded neutron spectra is determined to be ∼10 6 and ∼10 4 , respectively. For GRAVEL the same number is ∼10 7 and ∼3·10 4 for NE213 and MPR, respectively

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

    International Nuclear Information System (INIS)

    Ni Bangfa; Tian Weizhi; Nie Nuiling; Wang Pingsheng

    1999-01-01

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

  2. Status report on the development of a prompt fission neutron uranium borehole logging technique

    International Nuclear Information System (INIS)

    Smith, G.W.

    1977-05-01

    The prompt fission neutron (PFN) method of direct uranium measurement was studied. The PFN uranium logging technique measures the enhanced epithermal neutron population created by the prompt thermal fission of 235 U to assay uranium mineralization around a borehole. This neutron population exists for several hundred microseconds after a pulsed neutron source produces a burst of high energy (14 MeV) neutrons. A feasibility study established the basic relationship between the uranium concentration and the enhanced epithermal neutron count, and defined the major measurement perturbing factors. Following the feasibility study, development of a PFN prototype field probe was undertaken. A laboratory type neutron generator, the Controlatron, was modified for use in the probe. Field evaluation of the prototype system began in January 1976. Comparisons of neutron logs and natural gamma logs taken during this evaluation period clearly define many disequilibrium conditions as verified by ore grade estimates from core samples. The feasibility of the PFN logging technique to detect uranium in-situ has now been demonstrated

  3. Use of neutron probe and tensiometry techniques in determining ...

    African Journals Online (AJOL)

    Characterisation of soil water, in particular water flow dynamics is fundamental in assessing the environmental implications to soil management. Soil water characterisation was assessed by measuring soil water content and soil water potential in a draining profile of sandy and loamy soils. Mercury manometers and Neutron ...

  4. Instrumental Neutron Activation Analysis Technique using Subsecond Radionuclides

    DEFF Research Database (Denmark)

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

    1987-01-01

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

  5. Computational Modeling of a Time-Independent, Heterogeneous Reactor Core Using Simplified Discrete Ordinates Neutron Transport Techniques

    National Research Council Canada - National Science Library

    Labowski, Kristofer

    2001-01-01

    The Linear Characteristic (LC) method on rectangular boxoid meshes is a discrete ordinate neutron transport technique that uses both zeroth and first moments of the angular neutron flux to construct a relatively accurate...

  6. Dosimetric evaluation of the Fricke gel dosimeter using the spectrophotometric technique for application in electron and neutron dosimetry

    International Nuclear Information System (INIS)

    Mangueira, Thyago Fressatti

    2011-01-01

    The main dosimetric characteristics of the Fricke Xylenol Gel (FXG) solution were established for further application in the measurement of dose distribution of clinical electron fields. The dose-response curves of the FXG in a thermal neutron field were also evaluated for application in Boron Neutron Capture Therapy (BNCT) and industrial electron fields. The standard reading technique was the spectrophotometry. For clinical fields the intra and inter-batch reproducibility of FXG solution are better than 1.4% and 5.1%, respectively. The optical response presents a linear behavior for doses ranging from 0.2 to 40 Gy independently of the electron energy and the dose rate in the studied ranges. Due to the effects of the FXG natural oxidation, the optimum elapsed time between FXG preparation and irradiation was established as 24h. The behavior of the dose-response curve does not change the obtained absorbance values relative to the non-irradiated dosimeter response during the studied period. The dose-response curve to industrial electron beam presented an exponential decreasing behavior. The optical response to thermal neutrons beam presented a linear behavior for the studied dose range. According to the obtained results to the different radiation fields studied it was not observed changes in the wavelength of the typical bands of the absorption spectrum radiation induced. Additional tests were performed with FXG solution to verify the viability and application of FXG dosimetry on intracavitary brachytherapy using digital photographic imaging. The excellent performance of the FXG dosimeter indicates that this dosimeter may be applied to tri-dimensional dose evaluation in radiotherapy treatments using electrons and neutron beams. (author)

  7. Dosimetric evaluation of the Fricke gel dosimeter using the spectrophotometric technique for application in electron and neutron dosimetry

    International Nuclear Information System (INIS)

    Mangueira, Thyago Fressatti

    2009-01-01

    In this work the main dosimetric characteristics of the Fricke Xylenol Gel (FXG) solution were established for further application in the measurement of dose distribution of clinical electron fields. The dose-response curves of the FXG in a neutron field were also evaluated for the research in Boron Neutron Capture Therapy (BNCT) and industrial electron fields. The standard reading technique was the spectrophotometric. For the clinical field, the intra and inter-batch reproducibility are better than 1.4% and 5.1 %, respectively, the response presents a linear behavior for doses ranging from 0.2 to 40 Gy independently of the energy and the dose rate in the studied ranges. Due to the effects of the FXG natural oxidation, the optimum elapsed time between FXG preparation and irradiation was established as 24h period and the behavior of the dose-response curve of the FXG using the variation in the absorbance relative to the non-irradiated dosimeter as a basis during the whole studied period were not altered. The dose-response to the industrial electron beam presented an exponential decreasing behavior and the neutron beam for research in BNCT presented a linear behavior for the complete studied dose range. According to the obtained results for the different types of radiation studied for the FXG, there was no change in the position of the characteristic bands of the absorption spectrum due to the interaction of these radiation types. Additional tests were performed to determine the digital photographic imaging of FXG analyses viability and the application of FXG dosimetry on intracavitary brachytherapy. The good performance of the FXG dosimeter in the tests that were carried out indicates that this dosimeter may be applied to the tri-dimensional dose evaluation in radiotherapic treatments using electrons and neutron beams. (author)

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

    Science.gov (United States)

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

    2011-01-01

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

  9. Detector distance selection for ICF temperature measurements by neutron TOF techniques

    International Nuclear Information System (INIS)

    Lerche, R.A.; Remington, B.A.

    1990-01-01

    Fuel ion temperatures for laser-driven, inertial-confinement fusion targets are often determined by neutron time-of-flight (TOF) techniques. The error in the temperature measurement is a minimum at a target-to-detector distance that depends on both target and detector characteristics. The error is dominated by the detector response at shorter distances and by the number of detected neutrons at larger distances. We develop equations that relate the temperature error to the target ion temperature, the number of neutrons detected, target-to-detector distance, and the detector impulse response; and present sample calculations of the error for D-D and D-T plasmas observed by typical Nova neutron TOF detectors. The detector placement is important for minimizing temperature error for target yield below 10 10 neutrons. 4 refs., 2 figs

  10. Texture investigation in aluminium and iron - silicon samples by neutron diffraction technique

    International Nuclear Information System (INIS)

    Pugliese, R.; Yamasaki, J.M.

    1988-09-01

    By means of the neutron diffraction technique the texture of 5% and 98% rolled-aluminium and of iron-silicon steel used in the core of electric transformers, have been determined. The measurements were performed by using a neutron diffractometer installed at the IEA-R1 Nuclear Research Reactor, in the Beam-Hole n 0 . 6. To avoid corrections such as neutron absorption and sample luminosity the geometric form of the samples were approximated to spheric or octagonal prism, and its dimensions do not exceed that of the neutron beam. The texture of the samples were analysed with the help of a computer programme that analyses the intensity of the diffracted neutron beam and plot the pole figures. (author) [pt

  11. Technique investigation on large area neutron scintillation detector array

    International Nuclear Information System (INIS)

    Chen Jiabin

    2006-12-01

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

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

    International Nuclear Information System (INIS)

    Gomez, Angel; Bellino, Pablo A.

    2009-01-01

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

  13. Project ''PHANTOM'' - measurement of the absorbed dose, the ''averaged LET'' and the thermal neutron fluence in a tissue equivalent Phantom onboard space station MIR

    International Nuclear Information System (INIS)

    Berger, T.; Hajek, M.; Vana, N.; Schoener, W.; Akatov, Y.; Shurshakov, V.; Arkhangelsky, V.

    2001-01-01

    A water filled phantom with a diameter of 35 cm was developed at the Institute for Biomedical Problems. This tissue equivalent phantom is equipped with 4 channels to deposit dosemeters in different depths. In the framework of the project 'PHANTOM' (phase 1-3) thermoluminescent dosemeters of the commercially available Types TLD - 600 and TLD - 700 were exposed from May 1997 to February 1999 for an overall of 572 days in the different channels (perpendicular and normal to the hull of the spacecraft) of the phantom. The phantom was positioned in the commander cabin, the board engineer cabin and in the module KWANT 2. Besides the measurement of the depth dose distribution, the 'averaged LET' was determined using the HTR - method. The HTR - method utilizes the different LET - efficiencies of the main - and the high temperature glow peaks of LiF dosemeters for the evaluation of the 'averaged LET' in mixed radiation fields. Therefore it is possible to calculate the depth distribution of the biologically relevant dose equivalent. The results show, that despite of the depth decrease of the absorbed dose, the depth dose equivalent is almost constant. This can be explained by the production of secondary particles inside the phantom. The flux of the thermal neutrons was determined using the pair method. Calibration was performed at the research reactor of the Austrian Universities. First results show, that the contribution of thermal neutrons are roughly 10% of the total neutron dose equivalent. (orig.) [de

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

    International Nuclear Information System (INIS)

    Holly, Wiam Ahmed Alteghany

    2014-10-01

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

  15. The diagnostic technique of doppler width for low-yield neutrons

    International Nuclear Information System (INIS)

    Chen Jiabin; Teng Hao; Feng Jie; Zheng Zhijian; Tang Daoyuan; Liu Zhongli

    1997-01-01

    The author introduces the diagnostic technique of Doppler Width for low-yield neutrons by ultra-fast-quenched plastic scintillation detector. The relation between measurement error and detector position has been calculated. The result shows that the diagnostic method and detector can be used for as low as 10 7 ∼10 8 neutron yield and 2∼3 KeV ion temperature

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

    NARCIS (Netherlands)

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

    2008-01-01

    The neutron back-scattering (NBS) technique is a well established method to find hydrogen in objects. It can be applied in land mine detection taking advantage of the fact that land mines are abundant in hydrogen. The NBS technique is suitable for land mine scanning e.g., seeking for land mines with

  17. Visualization and measurement of fluid phenomena using neutron radiography techniques

    International Nuclear Information System (INIS)

    Mishima, Kaichiro; Hibiki, Takashi; Fujine, Shigenori; Yoneda, Kenji; Kanda, Keiji; Nishihara, Hideaki; Tsuruno, Akira; Matsubayashi, Masahito; Sobajima, Makoto; Ohtomo, Shoichi.

    1993-01-01

    This paper presents some of the results from recent work performed on the application of neutron radiography to visualization and measurement of fluid phenomena at the Research Reactor Institute of Kyoto University. Experiments have been performed on the following subjects with use of the NR systems at the Japan Research Reactor 3 and the Nuclear Safety Research Reactor of the Japan Atomic Energy Research Institute as well as the Kyoto University Research Reactor: air-water flow in rectangular ducts with 1.0 and 2.4 mm gaps, air-water flow and steam-water flow in a round tube with 4.0 mm inner diameter. The void fraction was measured by processing the images taken by the neutron radiography. The effect of several corrections in image processing was also discussed previously. It was shown that the proposed method could be useful in observing the flow regimes and measuring the void fraction of gas-liquid two-phase flow in narrow channels. (author)

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

    International Nuclear Information System (INIS)

    Goetsch, S.J.

    1983-01-01

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

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

    International Nuclear Information System (INIS)

    Ferreira, F.J.O.; Crispim, V.R.; Silva, A.X.

    2010-01-01

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

  20. Measurement of detector neutron energy response using time-of-flight techniques

    International Nuclear Information System (INIS)

    Janee, H.S.

    1973-09-01

    The feasibility of using time-of-flight techniques at the EG and G/AEC linear accelerator for measuring the neutron response of relatively sensitive detectors over the energy range 0.5 to 14 MeV has been demonstrated. The measurement technique is described in detail as are the results of neutron spectrum measurements from beryllium and uranium photoneutron targets. The sensitivity of a fluor photomultiplier LASL detector with a 2- by 1-inch NE-111 scintillator was determined with the two targets, and agreement in the region of overlap was very good. (U.S.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-06-15

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

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

    Science.gov (United States)

    Ferreira, F J O; Crispim, V R; Silva, A X

    2010-06-01

    In this study the development of a methodology to detect illicit drugs and plastic explosives is described with the objective of being applied in the realm of public security. For this end, non-destructive assay with neutrons was used and the technique applied was the real time neutron radiography together with computerized tomography. The system is endowed with automatic responses based upon the application of an artificial intelligence technique. In previous tests using real samples, the system proved capable of identifying 97% of the inspected materials. Copyright 2010 Elsevier Ltd. All rights reserved.

  3. Investigation of Non-Vacuum Deposition Techniques in Fabrication of Chalcogenide-Based Solar Cell Absorbers

    KAUST Repository

    Alsaggaf, Ahmed

    2015-07-01

    The environmental challenges are increasing, and so is the need for renewable energy. For photovoltaic applications, thin film Cu(In,Ga)(S,Se)2 (CIGS) and CuIn(S,Se)2 (CIS) solar cells are attractive with conversion efficiencies of more than 20%. However, the high-efficiency cells are fabricated using vacuum technologies such as sputtering or thermal co-evaporation, which are very costly and unfeasible at industrial level. The fabrication involves the uses of highly toxic gases such as H2Se, adding complexity to the fabrication process. The work described here focused on non-vacuum deposition methods such as printing. Special attention has been given to printing designed in a moving Roll-to-Roll (R2R) fashion. The results show potential of such technology to replace the vacuum processes. Conversion efficiencies for such non-vacuum deposition of Cu(In,Ga)(S,Se)2 solar cells have exceeded 15% using hazardous chemicals such as hydrazine, which is unsuitable for industrial scale up. In an effort to simplify the process, non-toxic suspensions of Cu(In,Ga)S2 molecular-based precursors achieved efficiencies of ~7-15%. Attempts to further simplify the selenization step, deposition of CuIn(S,Se)2 particulate solutions without the Ga doping and non-toxic suspensions of Cu(In,Ga)Se2 quaternary precursors achieved efficiencies (~1-8%). The contribution of this research was to provide a new method to monitor printed structures through spectral-domain optical coherence tomography SD-OCT in a moving fashion simulating R2R process design at speeds up to 1.05 m/min. The research clarified morphological and compositional impacts of Nd:YAG laser heat-treatment on Cu(In,Ga)Se2 absorber layer to simplify the annealing step in non-vacuum environment compatible to R2R. Finally, the research further simplified development methods for CIGS solar cells based on suspensions of quaternary Cu(In,Ga)Se2 precursors and ternary CuInS2 precursors. The methods consisted of post deposition reactive

  4. Fundamental studies for the proton polarization technique in neutron protein crystallography

    International Nuclear Information System (INIS)

    Tanaka, Ichiro; Kusaka, Katsuhiro; Chatake, Toshiyuki; Niimura, Nobuo

    2013-01-01

    Fundamental trials to realise the proton polarization technique for detecting hydrogen with higher sensitivity in neutron protein crystallography are described. The isotope effect in conventional neutron protein crystallography (NPC) can be eliminated by the proton polarization technique (ppt). Furthermore, the ppt can improve detection sensitivity of hydrogen (relative neutron scattering length of hydrogen) by approximately eight times in comparison with conventional NPC. Several technical difficulties, however, should be overcome in order to perform the ppt. In this paper, two fundamental studies to realise ppt are presented: preliminary trials using high-pressure flash freezing has shown the advantage of making bulk water amorphous without destroying the single crystal; and X-ray diffraction and liquid-chromatography/mass-spectrometry analyses of standard proteins after introducing radical molecules into protein crystals have shown that radical molecules could be distributed non-specifically around proteins, which is essential for better proton polarization

  5. Radiochemical separation and their application to neutron activation analysis technique

    International Nuclear Information System (INIS)

    Turel, Z.R.

    2013-01-01

    The present paper discusses the development of some new, rapid and selective method for the radiochemical separation and estimation of elements such as, Co(II) 2-3 , Ir(III) 4 , Au(III) 5 , Pt(IV), Pd(II), Os(IV) 6 , Cu(II), Ag(I), Mo(VI), Ni(II), Zn(II), Cd(II), Hg(II), Cs(I), Sb(III), La(III), Sc(III) etc. using various reagents. Various parameters such as pH, time of equilibrium, effect of anions and cations, effect of reagent etc. has been determined employing tracers of the elements under consideration and will be discussed. The method is made highly selective by the use of appropriate masking agent. The stoichiometry of metal reagent is determined by the substoichiometric method. Some examples of multielemental radiochemical separation methods thus developed which have been applied in determining the elements by radiochemical thermal neutron activation analysis will be presented and discussed. The implications of the results on the reference system will also be accounted. Statistical evaluation with reference to accuracy, precision and sensitivity will also be presented

  6. Neutron Diffraction Cryoporometry - A measurement technique for studying mesoporous materials and the phases of contained liquids and their crystalline forms

    OpenAIRE

    Webber, J. Beau W.; Dore, John C.

    2008-01-01

    Neutron diffraction is a standard method for determining the structure\\ud of matter on an atomic scale; NMR cryoporometry is a recent widely applicable technique for characterising structure on a 2 nm to 2 mu m scale. An extension of these techniques is described, Neutron Diffraction Cryoporometry (NDC). The information from a set of neutron\\ud diffraction measurements of liquids and their crystalline forms in meso-pores, as a function of temperature, is displayed as a cryoporometry graph. Th...

  7. Applications of neutron activation analysis technique in the IPR-R1 research reactor

    International Nuclear Information System (INIS)

    Sabino, C.V.S.; Mansur, N.

    1986-01-01

    A review is made of the neutron activation analysis technique used in the IPR-R1 reactor of the Centro de Desenvolvimento da Tecnologia Nuclear - NUCLEBRAS. Some characteristics of the method are described, types of samples and elements analyzed are also mentioned. (Author) [pt

  8. A Novel In-Beam Delayed Neutron Counting Technique for Characterization of Special Nuclear Materials

    Science.gov (United States)

    Bentoumi, G.; Rogge, R. B.; Andrews, M. T.; Corcoran, E. C.; Dimayuga, I.; Kelly, D. G.; Li, L.; Sur, B.

    2016-12-01

    A delayed neutron counting (DNC) system, where the sample to be analyzed remains stationary in a thermal neutron beam outside of the reactor, has been developed at the National Research Universal (NRU) reactor of the Canadian Nuclear Laboratories (CNL) at Chalk River. The new in-beam DNC is a novel approach for non-destructive characterization of special nuclear materials (SNM) that could enable identification and quantification of fissile isotopes within a large and shielded sample. Despite the orders of magnitude reduction in neutron flux, the in-beam DNC method can be as informative as the conventional in-core DNC for most cases while offering practical advantages and mitigated risk when dealing with large radioactive samples of unknown origin. This paper addresses (1) the qualification of in-beam DNC using a monochromatic thermal neutron beam in conjunction with a proven counting apparatus designed originally for in-core DNC, and (2) application of in-beam DNC to an examination of large sealed capsules containing unknown radioactive materials. Initial results showed that the in-beam DNC setup permits non-destructive analysis of bulky and gamma shielded samples. The method does not lend itself to trace analysis, and at best could only reveal the presence of a few milligrams of 235U via the assay of in-beam DNC total counts. Through analysis of DNC count rates, the technique could be used in combination with other neutron or gamma techniques to quantify isotopes present within samples.

  9. Neutron polarisers for diffraction experiments

    International Nuclear Information System (INIS)

    Cussen, L.D.; Goossens, D.J.; Hicks, T.J.

    2000-01-01

    Full text: Every neutron in a neutron beam has a spin which is either up or down. In an unpolarised beam, half the neutrons are up and half are down. A neutron polariser is a device which creates an imbalance in the number of up and down spin neutrons in the beam, thus giving a net beam polarisation. The three most common techniques for polarising neutron beams are supermirrors, Heusler alloy polarising monochromators and neutron spin filters. Supermirrors use the difference in refractive index for up and down spin neutrons at a magnetic/non-magnetic interface to selectively remove neutrons of one spin state from the beam. Heusler alloy polarisers give polarised beams through spin dependent Bragg reflection, and transmission filters work by preferentially absorbing the neutrons in one spin state. The most promising filter material is polarised gaseous 3 He, in which the lone neutron is polarised and then the atom will preferentially absorb a neutron of the opposite spin. All three techniques have different advantages. Here, we compare the three techniques by generating quality factors which relate closely to an instruments performance in an experiment and determining which polariser will give the best quality factor for a given type of experiment. We find that supermirrors give the best results when narrow angular divergence of the neutron beam is desired, while filters are best when short wavelengths and wide angular divergence is required. For a powder diffractometer, this implies that a supermirror would be used to polarise the incident beam, while a large array of supermirrors or a single curved transmission filter could be used to analyse the polarisation of the diffracted intensity. We note that while Heusler alloys have advantages in that they combine polarisation with monochromation, on purely performance based criteria, they are not competitive with supermirrors or well-developed transmission filter technology

  10. Analysis of boron utilization in sample preparation for microorganisms detection by neutron radiography technique

    International Nuclear Information System (INIS)

    Wacha, Reinaldo; Crispim, Verginia R.

    2000-01-01

    The neutron radiography technique applied to the microorganisms detection is the study of a new and faster alternative for diagnosis of infectious means. This work presents the parameters and the effects involved in the use of the boron as a conversion agent, that convert neutrons in a particles, capable ones of generating latent tracks in a solid state nuclear tracks detector, CR-39. The collected samples are doped with the boron by the incubation method, propitiating an interaction microorganisms/boron, that will guarantee the identification of the images of those microorganisms, through your morphology. (author)

  11. A comparison of reactor and linac techniques for neutron diffraction studies of molecular liquids

    International Nuclear Information System (INIS)

    Dore, J.C.; Clarke, J.H.

    1976-01-01

    A comparison is made of the experimental measurement of slow neutron diffraction from molecular liquids using a reactor (steady state) and a linac (pulsed) neutron source. Consideration is given to relative intensities, resolution and sample configuration for the two methods over a wide range of momentum transfer values. Possible errors in the liquid structure factor, Ssub(m)(Q), are examined in terms of established procedures for 'experimental' (absorption and multiple scattering) and 'analytic' (Placzek) corrections. The complementary nature of the two methods is emphasized and the implications for further development of the linac technique are examined. (Auth.)

  12. Investigation of an egyptian phosphate ore sample by neutron activation analysis technique

    International Nuclear Information System (INIS)

    Eissa, E.A.; Aly, R.A.; Rofail, N.B.; Hassan, A.M.

    1995-01-01

    A domestic phosphate ore sample has been analysed by means of prompt and delayed gamma-ray spectrometry following the activation by thermal neutron capture technique. The rabbit pneumatic transfer system (RPTS), long irradiation facility and two Pu/Be (2,5 Ci each) neutron sources set-Pu for prompt (n,gamma) were applied. The high purity germanium (HPGe) gamma-ray spectrometer with a personal computer analyzer (PCA) system were used for spectrum measurements. Programmes on the VAX computer were utilized for estimating the elemental concentrations of 22 out of 36 elements identified in this work. 2 tabs

  13. Dynamics of polymers in elongational flow studied by the neutron spin-echo technique

    International Nuclear Information System (INIS)

    Rheinstaedter, Maikel C.; Sattler, Rainer; Haeussler, Wolfgang; Wagner, Christian

    2010-01-01

    The nanoscale fluctuation dynamics of semidilute high molecular weight polymer solutions of polyethylenoxide (PEO) in D 2 O under non-equilibrium flow conditions were studied by the neutron spin-echo technique. The sample cell was in contraction flow geometry and provided a pressure driven flow with a high elongational component that stretched the polymers most efficiently. Neutron scattering experiments in dilute polymer solutions are challenging because of the low polymer concentration and corresponding small quasi-elastic signals. A relaxation process with relaxation times of about 10 ps was observed, which shows anisotropic dynamics with applied flow.

  14. Solar powered irrigation management using neutron scattering technique

    International Nuclear Information System (INIS)

    Hegazi, A.M.A

    2010-01-01

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

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

    International Nuclear Information System (INIS)

    Bellino, Pablo A.; Gomez, Angel

    2009-01-01

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

  16. Study of heterogeneous multiplying and non-multiplying media by the neutron pulsed source technique

    International Nuclear Information System (INIS)

    Deniz, V.

    1969-01-01

    The pulsed neutron technique consists essentially in sending in the medium to be studied a short neutron pulse and in determining the asymptotic decay constant of the generated population. The variation of the decay constant as a function of the size of the medium allows the medium characteristics to be defined. This technique has been largely developed these last years and has been applied as well to moderator as to multiplying media, in most cases homogeneous ones. We considered of interest of apply this technique to lattices, to see if useful informations could be collected for lattice calculations. We present here a general theoretical study of the problem, and results and interpretation of a series of experiments made on graphite lattices. There is a good agreement for non-multiplying media. In the case of multiplying media, it is shown that the age value used until now in graphite lattices calculations is over-estimated by about 10 per cent [fr

  17. Neutron diffraction tomography: a unique, 3D inspection technique for crystals using an intensifier TV system

    International Nuclear Information System (INIS)

    Davidson, J.B.; Case, A.L.

    1978-01-01

    The application of phosphor-intensifier-TV techniques to neutron topography and tomography of crystals is described. The older, analogous x-ray topography using wavelengths approximately 1.5A is widely used for surface inspection. However, the crystal must actually be cut in order to see diffraction anomalies beneath the surface. Because 1.5-A thermal neutrons are highly penetrating, much larger and thicker specimens can be used. Also, since neutrons have magnetic moments, they are diffracted by magnetic structures within crystals. In neutron volume topography, the entire crystal or a large part of it is irradiated, and the images obtained are superimposed reflections from the total volume. In neutron tomography (or section topography), a collimated beam irradiates a slice (0.5 to 10 mm) of the crystal. The diffracted image is a tomogram from this part only. A series of tomograms covering the crystal can be taken as the specimen is translated in steps across the narrow beam. Grains, voids, twinning, and other defects from regions down to 1 mm in size can be observed and isolated. Although at present poorer in resolution than the original neutron and film methods, the TV techniques are much faster and, in some cases, permit real-time viewing. Two camera systems are described: a counting camera having a 150 mm 6 Li-ZnS screen for low-intensity reflections which are integrated in a digital memory, and a 300-mm system using analog image storage. Topographs and tomograms of several crystals ranging in size from 4 mm to 80 mm are shown

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

    International Nuclear Information System (INIS)

    Forgan, E.M.; Charalambous, D.; Kealey, P.G.

    2002-01-01

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

  19. Influence of the neutron transport tube on neutron resonance densitometry

    Directory of Open Access Journals (Sweden)

    Kitatani Fumito

    2017-01-01

    Full Text Available Neutron Resonance Densitometry (NRD is a non-destructive assay technique of nuclear materials in particle-like debris that contains various materials. An aim of NRD is to quantify nuclear materials in a melting fuel of Fukusima Daiichi plant, spent nuclear fuel and annihilation disposal fuel etc. NRD consists of two techniques of Neutron Resonance Transmission Analysis (NRTA and Neutron Resonance Capture Analysis (NRCA or Prompt Gamma-ray Analysis (PGA. A density of nuclear material isotopes is decided with NRTA. The materials absorbing a neutron in a wide energy range such as boron in a sample are identified by NRCA/PGA. The information of NRCA/PGA is used in NRTA analysis to quantify nuclear material isotopes. A neutron time of flight (TOF method is used in NRD measurements. A facility, consisting of a neutron source, a neutron flight path, and a detector is required. A short flight path and a strong neutron source are needed to downsize such a facility and put NRD into practical use. A neutron transport tube covers a flight path to prevent noises. In order to investigate the effect of neutron transport tube and pulse width of a neutron source, we carried out NRTA experiments with a 2-m short neutron transport tube constructed at Kyoto University Research Reactor Institute - Linear Accelerator (KURRI-LINAC, and impacts of shield of neutron transport tube and influence of pulse width of a neutron source were examined. A shield of the neutron transport tube reduced a background and had a good influence on the measurement. The resonance dips of 183W at 27 eV was successfully observed with a pulse width of a neutron source less than 2 μs.

  20. Influence of the neutron transport tube on neutron resonance densitometry

    Science.gov (United States)

    Kitatani, Fumito; Tsuchiya, Harufumi; Koizumi, Mitsuo; Takamine, Jun; Hori, Junichi; Sano, Tadafumi

    2017-09-01

    Neutron Resonance Densitometry (NRD) is a non-destructive assay technique of nuclear materials in particle-like debris that contains various materials. An aim of NRD is to quantify nuclear materials in a melting fuel of Fukusima Daiichi plant, spent nuclear fuel and annihilation disposal fuel etc. NRD consists of two techniques of Neutron Resonance Transmission Analysis (NRTA) and Neutron Resonance Capture Analysis (NRCA) or Prompt Gamma-ray Analysis (PGA). A density of nuclear material isotopes is decided with NRTA. The materials absorbing a neutron in a wide energy range such as boron in a sample are identified by NRCA/PGA. The information of NRCA/PGA is used in NRTA analysis to quantify nuclear material isotopes. A neutron time of flight (TOF) method is used in NRD measurements. A facility, consisting of a neutron source, a neutron flight path, and a detector is required. A short flight path and a strong neutron source are needed to downsize such a facility and put NRD into practical use. A neutron transport tube covers a flight path to prevent noises. In order to investigate the effect of neutron transport tube and pulse width of a neutron source, we carried out NRTA experiments with a 2-m short neutron transport tube constructed at Kyoto University Research Reactor Institute - Linear Accelerator (KURRI-LINAC), and impacts of shield of neutron transport tube and influence of pulse width of a neutron source were examined. A shield of the neutron transport tube reduced a background and had a good influence on the measurement. The resonance dips of 183W at 27 eV was successfully observed with a pulse width of a neutron source less than 2 μs.

  1. Application of the neutron noise analysis technique in nuclear power plants

    International Nuclear Information System (INIS)

    Lescano, Victor H.; Wentzeis, Luis M.

    1999-01-01

    Using the neutron noise analysis in nuclear power plants, and without producing any perturbation in the normal operation of the plant, information of the vibration state of the reactor internals and the behavior of the operating conditions of the reactor primary circuit can be obtained. In Argentina, the neutron noise analysis technique is applied in customary way in the nuclear power plants Atucha I and Embalse. A database was constructed and vibration frequencies corresponding to different reactor internals were characterized. Reactor internals with particular mechanical vibrations have been detected and localized. In the framing of a cooperation project between Argentina and Germany, we participated in the measurements, analysis and modelisation, using the neutron noise technique, in the Obrigheim and Gundremmingen nuclear power plants. In the nuclear power plant Obrigheim (PWR, 350 M We), correlations between the signals measured from self-power neutron detectors and accelerometers located inside the reactor core, were made. In the nuclear power plant Gundremmingen (BWR, 1200 M We) we participated in the study of a particular mechanical vibration detected in one of the instrumentation tube. (author)

  2. Neutron scattering at high temperature and levitation techniques

    Science.gov (United States)

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

    2014-11-01

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

  3. Neutron scattering at high temperature and levitation techniques

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  4. BLINDAGE: A neutron and gamma-ray transport code for shieldings with the removal-diffusion technique coupled with the point-kernel technique

    International Nuclear Information System (INIS)

    Fanaro, L.C.C.B.

    1984-01-01

    It was developed the BLINDAGE computer code for the radiation transport (neutrons and gammas) calculation. The code uses the removal - diffusion method for neutron transport and point-kernel technique with buil-up factors for gamma-rays. The results obtained through BLINDAGE code are compared with those obtained with the ANISN and SABINE computer codes. (Author) [pt

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

    International Nuclear Information System (INIS)

    Mongkolphantha, S.; Karasuddhi, P.; Yamkate, P.; Serichareonsatit, N.

    1975-01-01

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

  6. PARTICLE SIZE-DEPENDENT PULVERIZATION OF B4C AND GENERATION OF B4C/STS NANOPARTICLES USED FOR NEUTRON ABSORBING COMPOSITES

    Directory of Open Access Journals (Sweden)

    JAEWOO KIM

    2014-10-01

    Full Text Available Pulverization of two different sized micro-B4C particles (∼10 μm and ∼150 μm was investigated using a STS based high energy ball milling system. Shapes, generation of the impurities, and reduction of the particle size dependent on milling time and initial particle size were investigated using various analytic tools including SEM-EDX, XRD, and ICP-MS. Most of impurity was produced during the early stage of milling, and impurity content became independent on the milling time after the saturation. The degree of particle size reduction was also dependent on the initial B4C size. It was found that the STS nanoparticles produced from milling is strongly bounded with the B4C particles forming the B4C/STS composite particles that can be used as a neutron absorbing nanocomposite. Based on the morphological evolution of the milled particles, a schematic pulverization model for the B4C particles was constructed.

  7. Use of borosilicate-glass raschig rings as a neutron absorber in solutions of fissile material-ANSI/ANS-8.5-1996

    International Nuclear Information System (INIS)

    Rothe, R.E.; Ketzlach, N.; Finch, D.R.

    1996-01-01

    American National Standards Institute/American Nuclear Society (ANSI/ANS)-8.5 is one of several standards prepared by the ANS Standards Committee to provide guidance to enhance criticality safety in the handling, storage, and processing of fissionable materials. American National Standard ANSI/ANS-8.5-1996 provides this guidance for one type of boron-loaded glass in one type of geometry (cylindrical rings) for use with fissile solutions. Recorded use of such fixed neutron absorbers for criticality control of fissile solutions dates back to 1958, but some less-well-documented applications were recorded as early as the mid-1940's. The first solid efforts to collect recommendations derived from experience and technology were begun in 1965. Over the next 6 yr additional experiments were performed, and supporting data for the proposed standard were gathered. The first standard on this safety matter was issued in 1971. It was reaffirmed in 1979 with only minor changes and a slight expansion of the coverage. The standard was last revised in 1986

  8. Characterization of plastic and boron carbide additive manufactured neutron collimators

    Science.gov (United States)

    Stone, M. B.; Siddel, D. H.; Elliott, A. M.; Anderson, D.; Abernathy, D. L.

    2017-12-01

    Additive manufacturing techniques allow for the production of materials with complicated geometries with reduced costs and production time over traditional methods. We have applied this technique to the production of neutron collimators for use in thermal and cold neutron scattering instrumentation directly out of boron carbide. We discuss the design and generation of these collimators. We also provide measurements at neutron scattering beamlines which serve to characterize the performance of these collimators. Additive manufacturing of parts using neutron absorbing material may also find applications in radiography and neutron moderation.

  9. Trace element analysis at the Livermore pool-type reactor using neutron activation techniques

    International Nuclear Information System (INIS)

    Ragaini, R.C.; Ralston, R.; Garvis, D.

    1975-01-01

    The capabilities of trace element analysis at the Livermore Pool-Type Reactor (LPTR) using instrumental neutron activation analysis (INAA) are discussed. A description is given of the technology and the methods employed, including sample preparation, irradiation, and analysis. Applications of the INAA technique in past and current projects are described. A computer program, GAMANAL, has been used for nuclide identification and quantification. (U.S.)

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

    Science.gov (United States)

    Latini, R. M.; Souza, M. I. S.; Almeida, G. L.; Bellido, A. V. B.

    2014-11-01

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

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

    International Nuclear Information System (INIS)

    Salifu, A. S.

    2015-01-01

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

  12. Absorber for nuclear radiations

    International Nuclear Information System (INIS)

    Planchamp, C.

    1987-01-01

    Neutrons, gamma and x radiations are highly absorbed by an alloy of gadolinium and aluminium. Workability, thermal conductivity, mechanical properties, corrosion resistance of the alloy are good. Possible applications are transport or storage of radioactive wastes or nuclear fuels, fuel racks, shelters, etc [fr

  13. The development of photo-transferred thermoluminescence (PTTL) technique and its application to the routine re-assessment of absorbed dose in the NRPB automated personal dosimetry system

    Science.gov (United States)

    McKinlay, A. F.; Bartlett, D. T.; Smith, P. A.

    1980-09-01

    The re-assessment of absorbed dose has been performed routinely on customer dosimeters as part of the NRPB Automated Thermoluminescence Dosimetry Service. The technique of photo-transferred thermoluminescence (PTTL), as applied to the 2 element (LiF: PTFE discs) NRPB dosimeter inserts, is described.

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

    International Nuclear Information System (INIS)

    Hudelot, J.P.

    1998-06-01

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

  15. Comparative study between the PIXE technique and neutron activation analysis for Zinc determination

    International Nuclear Information System (INIS)

    Cruvinel, Paulo Estevao; Crestana, Silvio; Artaxo Netto, Paulo Eduardo

    1997-01-01

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

  16. Measurements of the neutron dose equivalent for various radiation qualities, treatment machines and delivery techniques in radiation therapy.

    Science.gov (United States)

    Hälg, R A; Besserer, J; Boschung, M; Mayer, S; Lomax, A J; Schneider, U

    2014-05-21

    In radiation therapy, high energy photon and proton beams cause the production of secondary neutrons. This leads to an unwanted dose contribution, which can be considerable for tissues outside of the target volume regarding the long term health of cancer patients. Due to the high biological effectiveness of neutrons in regards to cancer induction, small neutron doses can be important. This study quantified the neutron doses for different radiation therapy modalities. Most of the reports in the literature used neutron dose measurements free in air or on the surface of phantoms to estimate the amount of neutron dose to the patient. In this study, dose measurements were performed in terms of neutron dose equivalent inside an anthropomorphic phantom. The neutron dose equivalent was determined using track etch detectors as a function of the distance to the isocenter, as well as for radiation sensitive organs. The dose distributions were compared with respect to treatment techniques (3D-conformal, volumetric modulated arc therapy and intensity-modulated radiation therapy for photons; spot scanning and passive scattering for protons), therapy machines (Varian, Elekta and Siemens linear accelerators) and radiation quality (photons and protons). The neutron dose equivalent varied between 0.002 and 3 mSv per treatment gray over all measurements. Only small differences were found when comparing treatment techniques, but substantial differences were observed between the linear accelerator models. The neutron dose equivalent for proton therapy was higher than for photons in general and in particular for double-scattered protons. The overall neutron dose equivalent measured in this study was an order of magnitude lower than the stray dose of a treatment using 6 MV photons, suggesting that the contribution of the secondary neutron dose equivalent to the integral dose of a radiotherapy patient is small.

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

    International Nuclear Information System (INIS)

    Wentzeis, Luis M.; Calvo, Maria D.

    2009-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

    The main dosimetric characteristics of the Fricke Xylenol Gel (FXG) solution were established for further application in the measurement of dose distribution of clinical electron fields. The dose-response curves of the FXG in a thermal neutron field were also evaluated for application in Boron Neutron Capture Therapy (BNCT) and industrial electron fields. The standard reading technique was the spectrophotometry. For clinical fields the intra and inter-batch reproducibility of FXG solution are better than 1.4% and 5.1%, respectively. The optical response presents a linear behavior for doses ranging from 0.2 to 40 Gy independently of the electron energy and the dose rate in the studied ranges. Due to the effects of the FXG natural oxidation, the optimum elapsed time between FXG preparation and irradiation was established as 24h. The behavior of the dose-response curve does not change the obtained absorbance values relative to the non-irradiated dosimeter response during the studied period. The dose-response curve to industrial electron beam presented an exponential decreasing behavior. The optical response to thermal neutrons beam presented a linear behavior for the studied dose range. According to the obtained results to the different radiation fields studied it was not observed changes in the wavelength of the typical bands of the absorption spectrum radiation induced. Additional tests were performed with FXG solution to verify the viability and application of FXG dosimetry on intracavitary brachytherapy using digital photographic imaging. The excellent performance of the FXG dosimeter indicates that this dosimeter may be applied to tri-dimensional dose evaluation in radiotherapy treatments using electrons and neutron beams. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Mangueira, Thyago Fressatti

    2009-07-01

    In this work the main dosimetric characteristics of the Fricke Xylenol Gel (FXG) solution were established for further application in the measurement of dose distribution of clinical electron fields. The dose-response curves of the FXG in a neutron field were also evaluated for the research in Boron Neutron Capture Therapy (BNCT) and industrial electron fields. The standard reading technique was the spectrophotometric. For the clinical field, the intra and inter-batch reproducibility are better than 1.4% and 5.1 %, respectively, the response presents a linear behavior for doses ranging from 0.2 to 40 Gy independently of the energy and the dose rate in the studied ranges. Due to the effects of the FXG natural oxidation, the optimum elapsed time between FXG preparation and irradiation was established as 24h period and the behavior of the dose-response curve of the FXG using the variation in the absorbance relative to the non-irradiated dosimeter as a basis during the whole studied period were not altered. The dose-response to the industrial electron beam presented an exponential decreasing behavior and the neutron beam for research in BNCT presented a linear behavior for the complete studied dose range. According to the obtained results for the different types of radiation studied for the FXG, there was no change in the position of the characteristic bands of the absorption spectrum due to the interaction of these radiation types. Additional tests were performed to determine the digital photographic imaging of FXG analyses viability and the application of FXG dosimetry on intracavitary brachytherapy. The good performance of the FXG dosimeter in the tests that were carried out indicates that this dosimeter may be applied to the tri-dimensional dose evaluation in radiotherapic treatments using electrons and neutron beams. (author)

  20. Burnable absorber coated nuclear fuel

    International Nuclear Information System (INIS)

    Chubb, W.; Radford, K.C.; Parks, B.H.

    1984-01-01

    A nuclear fuel body which is at least partially covered by a burnable neutron absorber layer is provided with a hydrophobic overcoat generally covering the burnable absorber layer and bonded directly to it. In a method for providing a UO 2 fuel pellet with a zirconium diboride burnable poison layer, the fuel body is provided with an intermediate niobium layer. (author)

  1. Study of some environmental problem in egypt using neutron activation analysis techniques

    International Nuclear Information System (INIS)

    El-Karim, A.H.M.G.

    2003-01-01

    this thesis deals with the investigation of the possibility of using the new (second) egyptian research reactor (ETRR-2) at Inshas (22 MW) for the neutron activation analysis (ANN) of trace elements, particularly in air dust, collected from cairo and some other cities of egypt. in this concern chapter 1 gives an introduction about the activation methods in general, describing the various techniques used and a comparison of the methods with other instrumental methods of analysis . as a main classification, the neutron activation methods involve prompt γ-ray NAA and delayed γ-ray NAA; cyclic NAA (repeated activation) was also outlined. the methodology of NAA involves the absolute method, the relative method and the mono standard (single comparator) method , which is in between the absolute and relative methods

  2. Fundamental studies for the proton polarization technique in neutron protein crystallography.

    Science.gov (United States)

    Tanaka, Ichiro; Kusaka, Katsuhiro; Chatake, Toshiyuki; Niimura, Nobuo

    2013-11-01

    The isotope effect in conventional neutron protein crystallography (NPC) can be eliminated by the proton polarization technique (ppt). Furthermore, the ppt can improve detection sensitivity of hydrogen (relative neutron scattering length of hydrogen) by approximately eight times in comparison with conventional NPC. Several technical difficulties, however, should be overcome in order to perform the ppt. In this paper, two fundamental studies to realise ppt are presented: preliminary trials using high-pressure flash freezing has shown the advantage of making bulk water amorphous without destroying the single crystal; and X-ray diffraction and liquid-chromatography/mass-spectrometry analyses of standard proteins after introducing radical molecules into protein crystals have shown that radical molecules could be distributed non-specifically around proteins, which is essential for better proton polarization.

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

    Science.gov (United States)

    González, Gabriela B

    2012-05-11

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

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

    Directory of Open Access Journals (Sweden)

    Gabriela B. González

    2012-05-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    J. W. Sterbentz; D. L. Chichester

    2011-09-01

    This is an end-of-year report (Fiscal Year (FY) 2011) for the second year of effort on a project funded by the National Nuclear Security Administration's Office of Nuclear Safeguards (NA-241). The goal of this project is to investigate the feasibility of using Neutron Resonance Transmission Analysis (NRTA) to assay plutonium in commercial light-water-reactor spent fuel. This project is part of a larger research effort within the Next-Generation Safeguards Initiative (NGSI) to evaluate methods for assaying plutonium in spent fuel, the Plutonium Assay Challenge. The second-year goals for this project included: (1) assessing the neutron source strength needed for the NRTA technique, (2) estimating count times, (3) assessing the effect of temperature on the transmitted signal, (4) estimating plutonium content in a spent fuel assembly, (5) providing a preliminary assessment of the neutron detectors, and (6) documenting this work in an end of the year report (this report). Research teams at Los Alamos National Laboratory (LANL), Lawrence Berkeley National Laboratory (LBNL), Pacific Northwest National Laboratory (PNNL), and at several universities are also working to investigate plutonium assay methods for spent-fuel safeguards. While the NRTA technique is well proven in the scientific literature for assaying individual spent fuel pins, it is a newcomer to the current NGSI efforts studying Pu assay method techniques having just started in March 2010; several analytical techniques have been under investigation within this program for two to three years or more. This report summarizes work performed over a nine month period from January-September 2011 and is to be considered a follow-on or add-on report to our previous published summary report from December 2010 (INL/EXT-10-20620).

  6. Software tool for resolution of inverse problems using artificial intelligence techniques: an application in neutron spectrometry

    International Nuclear Information System (INIS)

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

    2016-10-01

    The Taguchi methodology has proved to be highly efficient to solve inverse problems, in which the values of some parameters of the model must be obtained from the observed data. There are intrinsic mathematical characteristics that make a problem known as inverse. Inverse problems appear in many branches of science, engineering and mathematics. To solve this type of problem, researches have used different techniques. Recently, the use of techniques based on Artificial Intelligence technology is being explored by researches. This paper presents the use of a software tool based on artificial neural networks of generalized regression in the solution of inverse problems with application in high energy physics, specifically in the solution of the problem of neutron spectrometry. To solve this problem we use a software tool developed in the Mat Lab programming environment, which employs a friendly user interface, intuitive and easy to use for the user. This computational tool solves the inverse problem involved in the reconstruction of the neutron spectrum based on measurements made with a Bonner spheres spectrometric system. Introducing this information, the neural network is able to reconstruct the neutron spectrum with high performance and generalization capability. The tool allows that the end user does not require great training or technical knowledge in development and/or use of software, so it facilitates the use of the program for the resolution of inverse problems that are in several areas of knowledge. The techniques of Artificial Intelligence present singular veracity to solve inverse problems, given the characteristics of artificial neural networks and their network topology, therefore, the tool developed has been very useful, since the results generated by the Artificial Neural Network require few time in comparison to other techniques and are correct results comparing them with the actual data of the experiment. (Author)

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

    International Nuclear Information System (INIS)

    Cohen, I.M.

    1982-01-01

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

  8. Shock absorber

    International Nuclear Information System (INIS)

    Housman, J.J.

    1978-01-01

    A shock absorber is described for use in a hostile environment at the end of a blind passage for absorbing impact loads. The shock absorber includes at least one element which occupies the passage and which is comprised of a porous brittle material which is substantially non-degradable in the hostile environment. A void volume is provided in the element to enable the element to absorb a predetermined level of energy upon being crushed due to impact loading

  9. Direct measurement of the cross section of neutron-neutron scattering at the YAGUAR reactor. Substantiation of the experiment technique

    International Nuclear Information System (INIS)

    Chernukhin, Yu.G.; Kandiev, Ya.Z.; Lartsev, V.D.; Levakov, B.G.; Modestov, D.G.; Simonenko, V.A.; Streltsov, S.I.; Khmel'nitskij, D.V.

    2006-01-01

    The main stage of experiment for direct measurement of cross section of neutron-neutron scattering σ nn at low energies (E nn determination. It was shown, that for achieving the criterion ε ∼ 4% it will be necessary to have 40-50 pulses of a reactor [ru

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

    International Nuclear Information System (INIS)

    Soliman, M.A.M.

    2012-01-01

    The work presented in this thesis covers two major points. One algorithm concerns with establishment of an accurate standardization method with multi-elemental capabilities and low workload suitable for NAA standardization at ETRR-2. The second one deals with constructing and developing an effective nondestructive technique for analysis of liquid samples based on NAA using (very) short-lived radionuclides. To achieve the first goal, attention has been directed toward implementation of the k 0 -method for calculation of the elements concentrations in the samples. The k 0 -method of NAA standardization has a considerable success as a method for accurate multi-elemental analysis with comparable low workload. The k 0 - method is based on the fact that the unknown sample is irradiated with only one standard element as comparator. To access the implementation of this method at ETRR-2, careful and complete characterization of the neutron flux parameters in the irradiation positions as well as the efficiency calibration of the γ-ray spectrometer must be carried out. The required neutron flux parameters are: the ratio of the thermal to epithermal neutron fluxes (f) and the deviation factor (α) of the epithermal neutron flux from the ideal 1/E law. The work presented in Chapter 4 shows the efficiency calibration curve of the γ ray spectrometer system which was obtained using standard radioactive point sources. Moreover, the f and α parameters were determined in some selected irradiation sites using sets of Zr-Au as neutron flux monitors. Due to different locations relative to the reactor core, the available neutron fluxes in the selected irradiation positions differ substantially, so that different irradiation demands can be satisfied. The reference materials coal NIST 1632c and IAEA-Soil 7 were analyzed for data validation and good agreement between the experimental values and the certified values was obtained. The obtained results have revealed that the k 0 -NAA

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

    International Nuclear Information System (INIS)

    Van der Zaag, P.J.; Feiner, L.F.; Wolf, R.M.; Gaines, J.M.; Ijiri, Y.; Borchers, J.A.; Erwin, R.W.

    1999-01-01

    Complete text of publication follows. Recently, the interest in exchange biasing (i.e. the coupling between the antiferromagnetic (AF) and ferromagnetic (F) layers) surged, due to its relevance for GMR spin-valves. Using Fe 3 O 4 /CoO as a model system, it is shown how neutron techniques are crucial in unraveling the nature of the coupling at the buried AF-F interface. Neutron diffraction has shown that the coupling at the interface is not collinear as thus far assumed but perpendicular [1], in agreement with the recent theory by Koon [2]. However, further study by a.o. high- and low-angle neutron diffraction shows that no parallel AF domain wall (can) exists within the AF-layer as assumed by Koon. This suggests that the recent theory by Schulthess-Butler, which finds a perpendicular AF-F coupling on the basis of roughness and a perpendicular domain wall formation in the AF [3], might offer a better framework to understand biasing. The issue of T N in ultrathin CoO layers and its connection to the reduction of the blocking temperature observed in biased AF/F bilayers are also discussed. (author)

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

    International Nuclear Information System (INIS)

    Laurent, J.P.

    2000-01-01

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

  13. Deformation processes in functional materials studied by in situ neutron diffraction and ultrasonic techniques

    International Nuclear Information System (INIS)

    Sittner, P.; Novak, V.; Landa, M.; Lukas, P.

    2007-01-01

    The unique thermomechanical functions of shape memory alloys (hysteretic stress-strain-temperature responses) not their structural properties (as strength, fatigue, corrosion resistance, etc.) are primarily utilized in engineering applications. In order to better understand and predict the functional behavior, we have recently employed two dedicated non-invasive in situ experimental methods capable to follow the deformation/transformation processes in thermomechanically loaded polycrystalline samples. The in situ neutron diffraction method takes advantage of the ability of thermal neutrons to penetrate bulk samples. As a diffraction technique sensitive to interplanar spacings in crystalline solids, it provides in situ information on the changes in crystal structure, phase composition, phase stress and texture in the transforming samples. The combined in situ ultrasonic and electric resistance method follows variations of the electric resistance as well as speed and attenuation of acoustic waves propagating through the transforming sample. The acoustic waves are mainly sensitive to changes of elastic properties accompanying the deformation/transformation processes. The latter method thus follows the changes in interatomic bonds rather than changes in the interplanar lattice spacings focused in the neutron diffraction method. The methods are thus complementary. They are briefly described and selected experimental results obtained recently on NiTi alloys are presented and discussed

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  15. Neutron time-of-flight techniques for investigation of the extinction effect

    International Nuclear Information System (INIS)

    Niimura, N.; Tomiyoshi, S.; Takahashi, J.; Harada, J.

    1975-01-01

    An application of the time-of-flight neutron diffraction technique to an investigation of the nature of the extinction effect in a single-crystal specimen is given. It is shown that the wavelength dependence of the extinction can be easily obtained by changing the scattering angle. An estimation of the extinction factor for a CuCl single crystal is given as an example and a comparison of the results with recent extinction theory [Becker and Coppens. Acta Cryst.(1974). A30, 129-147; 148-153] is made. (Auth.)

  16. Quantitation of water in membranes by neutron diffraction and X-ray techniques.

    Science.gov (United States)

    Knott, R B; Schoenborn, B P

    1986-01-01

    The general principle of placing neutron and X-ray scattering density profiles on an absolute scale is being applied to an increasing number of problems in structural biology. This maximizes the information from the experiments by facilitating the identification of various molecular species. The greater detail available on the membrane water distribution has been highlighted in this chapter. The quantitative analysis of water in the headgroup region and the intermembrane water layer provides valuable information on membrane structure and function. The single most important limitation of the method is the lack of resolution. Improvements in experimental techniques will improve the resolution in a number of situations.

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

    International Nuclear Information System (INIS)

    Abdel-Haleem, A.S.; Zaghloul, R.A.; Sroor, A.; Abdel Sabour, M.F.

    2000-01-01

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

  18. Investigation of Lecturer's Chalk by x-ray Florescence and Fast Neutron Activation Techniques

    International Nuclear Information System (INIS)

    Hassan, M.F.

    2011-01-01

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

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

    International Nuclear Information System (INIS)

    Hassan, M. F.; Abd El Wahab, M.; Nada, A.

    2008-01-01

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

  20. Sensitivity Measurements For Cargo Scanning Applications Using Photon Interrogation and Neutron Signature Counting Techniques

    Science.gov (United States)

    Ankrah, Maxwell

    2011-12-01

    In recent years, non-destructive evaluation techniques which use either photon or neutron sources from accelerators followed by neutron counting signatures have been used in many national security and nuclear nonproliferation applications [4, 60]. Although the United States customs and border protection initiated and implemented a cargo security initiative to discover threats from others countries before they embark to the US, detectors with better sensitivities are more necessary than ever in view of the global threats faced by nations around the world. Photofission based applications which use delayed neutron signal ores as viable detection schemes for fissile material detection have been ongoing for many years. Applications of this technology to include cargo scanning applications are however lacking. This work in this dissertation used the delayed neutron signature counting technique for fissile material detection in conjunction with new formulated Curries' expressions to establish the sensitivity (minimum detectable mass) limits. The fission reactions were induced in a uranyl nitrate solution containing 94.1 g of 238U using bremsstrahlung endpoint cue pies of 9 MeV to 21 MeV in 2 MeV steps. Preliminary data on the sensitvity measurement at bremsstrahlung end point energies of 9, 14, 18 and 22 MeV are also presented. We also present the effect of borated polyethylene and lead shielding on the sensitivity at 9 and 22 N1cV. The sensitivities were calculated for 5%u false positives and 5% fake negatives as well as for 1% false positives and 0.1% false negatives. A dose of 4 Gy, 5 mGy and 1 mGy were assumed to be delivered to Mutt cargo container. For a radiator and target-to-detector distance of 150 cm and 200 cup, the delayed neutron yield from calculation and experiment was also compared. Finally, feasibility studies was conducted to determine if the linac parameters used in this research was capable of detecting 1 mg, 1 g and 1 kg of 238U. This work was funded

  1. Thick-foils activation technique for neutron spectrum unfolding with the MINUIT routine-Comparison with GEANT4 simulations

    Science.gov (United States)

    Vagena, E.; Theodorou, K.; Stoulos, S.

    2018-04-01

    Neutron activation technique has been applied using a proposed set of twelve thick metal foils (Au, As, Cd, In, Ir, Er, Mn, Ni, Se, Sm, W, Zn) for off-site measurements to obtain the neutron spectrum over a wide energy range (from thermal up to a few MeV) in intense neutron-gamma mixed fields such as around medical Linacs. The unfolding procedure takes into account the activation rates measured using thirteen (n , γ) and two (n , p) reactions without imposing a guess solution-spectrum. The MINUIT minimization routine unfolds a neutron spectrum that is dominated by fast neutrons (70%) peaking at 0.3 MeV, while the thermal peak corresponds to the 15% of the total neutron fluence equal to the epithermal-resonances area. The comparison of the unfolded neutron spectrum against the simulated one with the GEANT4 Monte-Carlo code shows a reasonable agreement within the measurement uncertainties. Therefore, the proposed set of activation thick-foils could be a useful tool in order to determine low flux neutrons spectrum in intense mixed field.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-01-19

    This article describes the design features and the first test measurements obtained during the installation of a novel high resolution 2D neutron detection technique. The technique proposed in this work consists of a boron layer (enriched in ${^{10}}$B) placed on a scientific Charge Coupled Device (CCD). After the nuclear reaction ${^{10}}$B(n,$\\alpha$)${^{7}}$Li, the CCD detects the emitted charge particles thus obtaining information on the neutron absorption position. The above mentioned ionizing particles, with energies in the range 0.5-5.5 MeV, produce a plasma effect in the CCD which is recorded as a circular spot. This characteristic circular shape, as well as the relationship observed between the spot diameter and the charge collected, is used for the event recognition, allowing the discrimination of undesirable gamma events. We present the first results recently obtained with this technique, which has the potential to perform neutron tomography investigations with a spatial resolution better than that previously achieved. Numerical simulations indicate that the spatial resolution of this technique will be about 15 $\\mu$m, and the intrinsic detection efficiency for thermal neutrons will be about 3 %. We compare the proposed technique with other neutron detection techniques and analyze its advantages and disadvantages.

  3. Photon and neutron interrogation techniques for chemical explosives detection in air cargo: A critical review

    International Nuclear Information System (INIS)

    Runkle, Robert C.; White, Timothy A.; Miller, Erin A.; Caggiano, Joseph A.; Collins, Brian A.

    2009-01-01

    Scanning cargo transported via aircraft ('air cargo') for explosive threats is a problem that presently lacks a comprehensive technical solution. While chemical explosives detection in the baggage-scanning domain has a rich history that sheds light on potential solutions, air cargo differs in several important ways, and thus one cannot look to the present array of technologies. Some contemporary solutions, such as trace analysis, are not readily applied to cargo because of sampling challenges while the larger geometry of air cargo makes others less effective. This review article examines an array of interrogation techniques using photons and neutrons as incident particles. We first present a summary of the signatures and observables chemical explosives provide and review how they have been exploited in baggage scanning. Following this review is a description of the challenges posed by the air-cargo application space. After considering sources of photons and neutrons, we describe methods focused on transmission imaging, sub-surface examination, and elemental characterization. It is our goal to expand the understanding of each method's technical promise while largely deferring questions that revolve around footprint, safety, and conduct of operations. Our overarching intent is that a comprehensive understanding of potential techniques will foster the development of a comprehensive solution.

  4. Fourier-filtering techniques for the analysis of high-resolution pulsed neutron powder diffraction data

    International Nuclear Information System (INIS)

    Richardson, J.W. Jr.; Faber, J. Jr.

    1985-01-01

    Rietveld profile refinements using high-resolution pulsed neutron powder diffraction data, collected at IPNS, often reveal broad intensity contributions from sources other than the crystalline materials being studied. Such non-crystalline intensity hampers standard Rietveld refinement, and its removal and/or identification is imperative for successful refinement of the crystalline structure. A Fourier-filtering technique allows removal of the non-crystalline scattering contributions to the overall scattering pattern and yields information about the noncrystalline material. In particular, Fourier transformation of residual intensities not accounted for by the Rietveld procedure results in a real-space correlation function similar to a radial distribution function (RDF). From the inverse Fourier transform of the correlation function a Fourier-filtered fit to the diffuse scattering is obtained. This mathematical technique was applied to data for crystalline quartz, amorphous silica, and to a simulated diffraction pattern for a mixture of the two phases. 7 refs., 4 figs., 1 tab

  5. A-TEEMTM, a new molecular fingerprinting technique: simultaneous absorbance-transmission and fluorescence excitation-emission matrix method

    Science.gov (United States)

    Quatela, Alessia; Gilmore, Adam M.; Steege Gall, Karen E.; Sandros, Marinella; Csatorday, Karoly; Siemiarczuk, Alex; (Ben Yang, Boqian; Camenen, Loïc

    2018-04-01

    We investigate the new simultaneous absorbance-transmission and fluorescence excitation-emission matrix method for rapid and effective characterization of the varying components from a mixture. The absorbance-transmission and fluorescence excitation-emission matrix method uniquely facilitates correction of fluorescence inner-filter effects to yield quantitative fluorescence spectral information that is largely independent of component concentration. This is significant because it allows one to effectively monitor quantitative component changes using multivariate methods and to generate and evaluate spectral libraries. We present the use of this novel instrument in different fields: i.e. tracking changes in complex mixtures including natural water, wine as well as monitoring stability and aggregation of hormones for biotherapeutics.

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

    International Nuclear Information System (INIS)

    Sablik, M.J.; Kwun, H.; Rollwitz, W.L.; Cadena, D.

    1992-01-01

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

  7. Estimation of organ-absorbed radiation doses during 64-detector CT coronary angiography using different acquisition techniques and heart rates: a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Matsubara, Kosuke; Koshida, Kichiro; Kawashima, Hiroko (Dept. of Quantum Medical Technology, Faculty of Health Sciences, Kanazawa Univ., Kanazawa (Japan)), email: matsuk@mhs.mp.kanazawa-u.ac.jp; Noto, Kimiya; Takata, Tadanori; Yamamoto, Tomoyuki (Dept. of Radiological Technology, Kanazawa Univ. Hospital, Kanazawa (Japan)); Shimono, Tetsunori (Dept. of Radiology, Hoshigaoka Koseinenkin Hospital, Hirakata (Japan)); Matsui, Osamu (Dept. of Radiology, Faculty of Medicine, Kanazawa Univ., Kanazawa (Japan))

    2011-07-15

    Background: Though appropriate image acquisition parameters allow an effective dose below 1 mSv for CT coronary angiography (CTCA) performed with the latest dual-source CT scanners, a single-source 64-detector CT procedure results in a significant radiation dose due to its technical limitations. Therefore, estimating the radiation doses absorbed by an organ during 64-detector CTCA is important. Purpose: To estimate the radiation doses absorbed by organs located in the chest region during 64-detector CTCA using different acquisition techniques and heart rates. Material and Methods: Absorbed doses for breast, heart, lung, red bone marrow, thymus, and skin were evaluated using an anthropomorphic phantom and radiophotoluminescence glass dosimeters (RPLDs). Electrocardiogram (ECG)-gated helical and ECG-triggered non-helical acquisitions were performed by applying a simulated heart rate of 60 beats per minute (bpm) and ECG-gated helical acquisitions using ECG modulation (ECGM) of the tube current were performed by applying simulated heart rates of 40, 60, and 90 bpm after placing RPLDs on the anatomic location of each organ. The absorbed dose for each organ was calculated by multiplying the calibrated mean dose values of RPLDs with the mass energy coefficient ratio. Results: For all acquisitions, the highest absorbed dose was observed for the heart. When the helical and non-helical acquisitions were performed by applying a simulated heart rate of 60 bpm, the absorbed doses for heart were 215.5, 202.2, and 66.8 mGy for helical, helical with ECGM, and non-helical acquisitions, respectively. When the helical acquisitions using ECGM were performed by applying simulated heart rates of 40, 60, and 90 bpm, the absorbed doses for heart were 178.6, 139.1, and 159.3 mGy, respectively. Conclusion: ECG-triggered non-helical acquisition is recommended to reduce the radiation dose. Also, controlling the patients' heart rate appropriately during ECG-gated helical acquisition with

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

    Science.gov (United States)

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

    2016-11-01

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

  9. Analysis and development of deterministic and stochastic neutron noise computing techniques with applications to thermal and fast reactors

    International Nuclear Information System (INIS)

    Rouchon, Amelie

    2016-01-01

    Neutron noise analysis addresses the description of small time-dependent flux fluctuations induced by small global or local perturbations of the macroscopic cross-sections. These fluctuations may occur in nuclear reactors due to density fluctuations of the coolant, to vibrations of fuel elements, control rods, or any other structures in the core. In power reactors, ex-core and in-core detectors can be used to monitor neutron noise with the aim of detecting possible anomalies and taking the necessary measures for continuous safe power production. The objective of this thesis is to develop techniques for neutron noise analysis and especially to implement a neutron noise solver in the deterministic transport code APOLLO3 developed at CEA. A new Monte Carlo algorithm that solves the transport equations for the neutron noise has been also developed. In addition, a new vibration model has been developed. Moreover, a method based on the determination of a new steady state has been proposed for the linear and the nonlinear full theory so as to improve the traditional neutron noise theory. In order to test these new developments we have performed neutron noise simulations in one-dimensional systems and in a large pressurized water reactor with heavy baffle in two and three dimensions with APOLLO3 in diffusion and transport theories. (author) [fr

  10. Synthesis of poly (acrylamide-co-metacrylic acid) hydrogels By means of gamma irradiation techniques: influence of Absorbed dose on the swelling process

    International Nuclear Information System (INIS)

    Rapado, Manuel; Altanes, Sonia; Sainz, Dianelys; Prado, Stalina

    1999-01-01

    In this report gamma radiation techniques were performed a double function of proceeding the processes of polymerization and crosslinking with the advantage of avoid the uses of chemicals crosslinks. The influence of absorbed dose on the swelling ratio as a function of pH have been presented. For these hydrogels, swelling studies indicated that swelling decrease with the increase of the absorbed dose from 10 to 50 kGy. It was confirmed that at the firsts stages (100-150 min) the diffusion studies were in accordance with Fickian behavior and the diffusion coefficients were obtained, whereas the latest stages were in good agreement with second-order diffusion kinetics proposed by Schott 1 .These news hydrogels exhibit a higher degree of swelling, a factor that, a priori, assures high biocompatibility because it increases the similarity with living tissues

  11. Effects of neutron irradiation on optical and chemical properties of CR-39: Potential application in neutron dosimetry

    International Nuclear Information System (INIS)

    Sahoo, G.S.; Paul, S.; Tripathy, S.P.; Sharma, S.C.; Jena, S.; Rout, S.; Joshi, D.S.; Bandyopadhyay, T.

    2014-01-01

    Effects of high-dose neutron irradiation on chemical and optical properties of CR-39 were studied using FTIR (Fourier Transform Infrared) and UV–vis (Ultraviolet–Visible) spectroscopy. The primary goal was to find a correlation between the neutron dose and the corresponding changes in the optical and chemical properties of CR-39 resulted from the neutron irradiation. The neutrons were produced by bombarding a thick Be target with 22-MeV protons. In the FTIR spectra, prominent absorbance peaks were observed at 1735 cm −1 (C=O stretching), 1230 cm −1 (C–O–C stretching), and 783 cm −1 (=C–H bending), the intensities of which decreased with increasing neutron dose. The optical absorbance in the visible range increased linearly with the neutron dose. Empirical relations were established to estimate neutron doses from these optical properties. This technique is particularly useful in measuring high doses, where track analysis with an optical microscope is difficult because of track overlapping. - Highlights: • CR-39 optical absorbance measurements can be used for neutron dosimetry instead of track counting. • The technique is particularly useful for measuring high doses. • Effects of neutron irradiations on various properties of CR-39 have been characterized

  12. Spectra and absorbed dose by photo-neutrons in a solid water mannequin exposed to a Linac of 15 MV; Espectros y dosis absorbida por fotoneutrones en un maniqui de agua solida expuesta a una Linac de 15 MV

    Energy Technology Data Exchange (ETDEWEB)

    Benites R, J. [Centro Estatal de Cancerologia de Nayarit, Servicio de Seguridad Radiologica, Calz. de la Cruz 118 Sur, 63000 Tepic, Nayarit (Mexico); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Apdo. Postal 336, 98000 Zacatecas (Mexico); Velazquez F, J., E-mail: jlbenitesr@prodigy.net.mx [Universidad Autonoma de Nayarit, Posgrado en Ciencias Biologico Agropecuarias, Carretera Tepic-Compostela Km 9, 63780 Jalisco-Nayarit (Mexico)

    2012-10-15

    Using Monte Carlo methods was modeled a solid water mannequin; according to the ICRU 44 (1989), Tissue substitutes in radiation dosimetry and measurements, of the International Commission on Radiation Units and Measurements; Report 44. This material Wt 1 is made of H (8.1%), C (67.2%), N (2.4%), O (19.9%), Cl (0.1%), Ca (2.3%) and its density is of 1.02 gr/cm{sup 3}. The mannequin was put instead of the patient, inside the treatment room and the spectra and absorbed dose were determined by photo-neutrons exposed to a Linac of 15 MV. (Author)

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

    Science.gov (United States)

    Baers, L. B.; Gutierrez, T. Rivero; Mendoza, R. A. Carrillo; Santana, G. Jimenez

    1993-08-01

    The second (conventional variance or Campbell signal), the third, and the modified fourth order central signal moments associated with the amplified and filtered currents from two electrodes of an ex-core neutron sensitive fission detector were measured versus the reactor power of the 1-MW TRIGA reactor in Mexico City. Two channels of a high-speed (400-MHz) multiplexing data sampler and an analog-to-digital converter with 12-b resolution and 1-Mword buffer memory were used. The data were further retrieved into a PC, and estimates for autocorrelation and cross-correlation moments up to the fifth order, coherence, skewness, excess, etc., quantities were calculated offline. Five-mode operation of the detector was achieved, including conventional counting rates and currents in agreement with theory and the authors' previous results with analog techniques. The signals are proportional to the neutron flux and reactor power in some flux ranges. The suppression of background noise is improved and the lower limit of the measurement range is extended as the order of moment is increased, in agreement with theory.

  14. Techniques for characterization of particulate matter: neutron activation analysis, x-ray photoelectron spectroscopy, scanning electron microscopy

    International Nuclear Information System (INIS)

    Hulett, L.D.; Dale, J.M.; Emery, J.F.; Lyon, W.S. Jr.; Fulkerson, W.

    1975-01-01

    Three techniques for particulate matter analysis are discussed: (1) neutron activation, which is a method that samples the entire specimen, both surface and bulk; (2) electron spectroscopy for chemical analysis (ESCA), which samples particle surfaces only; and (3) scanning electron microscopy (SEM), which reveals particle size and morphology, and can be used to determine composition differences in individual particles. These three techniques can be combined to construct highly detailed characterizations of particulate matter specimens. It is shown that multielement analysis can be quickly done by neutron activation and that surface analysis and individual particle analysis obtained by ESCA and SEM, are very important supplementary information

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

    Science.gov (United States)

    Xiong, Yong; Ding, Yongkun; Zheng, Zhijian; Chen, Ming

    2004-06-01

    The neutron Doppler broadening in inertial confinement fusion has been acquired from the time of flight for the neutron, from which the fuel ion temperature can be derived. An ultrafast-quenched plastic scintillation detector was used to measure the time of flight for the neutron at a low-imploded DT neutron yield (5×107-1×108) in the experiment performed on the Shenguang II laser facility. The typical temperatures of ablating targets for indirect drive were around 2.8 keV and the uncertainties were ±30%-±40%. The detection efficiency of the detector for DT neutrons was calibrated at a K-400 accelerator. The time response function of the detection system was calibrated by imploded neutrons from a DT-filled capsule, which can be regarded as a δ function pulsed neutron source due to its much narrower pulse width than that of the measured neutron time-of-flight spectrum.

  16. Diagnostic technique of neutron doppler broadening for indirectly-driven implosions

    International Nuclear Information System (INIS)

    Xiong Yong; Ding Yongkun; Zheng Zhijian; Chen Ming

    2004-01-01

    The neutron Doppler broadening in inertial confinement fusion has been acquired from the time of flight for the neutron, from which the fuel ion temperature can be derived. An ultrafast-quenched plastic scintillation detector was used to measure the time of flight for the neutron at a low-imploded DT neutron yield (5 x 10 7 - 1 x 10 8 ) in the experiment performed on the Shenguang II laser facility. The typical temperatures of ablating targets for indirect drive were around 2.8 keV and the uncertainties were ±30%-±40%. The detection efficiency of the detector for DT neutrons was calibrated at a K-400 accelerator. The time response function of the detection system was calibrated by imploded neutrons from a DT-filled capsule, which can be regarded as a δ function pulsed neutron source due to its much narrower pulse width than that of the measured neutron time-of-flight spectrum. (authors)

  17. Evaluation of the natural radioactivity using thermoluminescence, gamma spectrometry and neutron activation techniques

    International Nuclear Information System (INIS)

    Fausto, A.M.; Otsubo, S.M.; Paes, W.S.; Yoshimura, E.M.; Okuno, E.; Hiodo, F.; Marques, L.S.; Alcala, A.L.

    1996-01-01

    The evaluation of the radiation dose in the living species due to the natural radioactivity is the main objective of this paper. The region that had been monitored was Intrusive Suite of Itu near to Sao Paulo city. Lateral[and depth distributions of natural radioactivity of the soil were determined using the techniques of thermoluminescence gamma spectrometry and neutron[activation. From the concentration in the soil of K-40 and radioactive elements of U and Th series experimentally determined, the dose due to gamma rays in air at 1 m from the soil was evaluated and the results compared with the direct dose measured with the portable rate-meter. (authors). 11 refs., 3 figs

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

    Directory of Open Access Journals (Sweden)

    Roberto Triolo

    2010-12-01

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

  19. Study on the hydration of oriented DNA by the neutron scattering technique

    International Nuclear Information System (INIS)

    Dahlborg, U.; Dimic, V.; Rupprecht, A.

    1980-01-01

    Three different experimental methods of neutron scattering have been employed in order to study the hydration problem in various forms of oriented DNA fibrils. It is found that the water of hydration forms an internal structure in the samples and that this structure is not very strongly coupled to the macromolecular surface. The existence of hydrogen bonds between water molecules is clearly demonstrated. Qualitative agreement between calculated structure factors and measured 'elastic' diffraction patterns for a dry DNA sample is obtained. In order to reproduce the measured diffraction pattern for a wet sample it is not enough to include only the water molecules within the first hydration shell in a structure factor calculation. It is concluded that by employing the high resolution 'elastic' diffraction technique it should be possible to obtain detailed information on the problem of hydration in DNA. (Auth.)

  20. Neutron activation analysis - an old technique but is it still useful?

    International Nuclear Information System (INIS)

    McOrist, G.D.

    1998-01-01

    Neutron activation analysis (NAA) is a non-destructive technique of analysis making it particularly suitable to analyse certain types of samples or particular elements, such as diamonds, black precious opal and ancient fish fossil bones. It is particularly suited to analysing solid samples since no sample dissolution, with its associated problems, prior to analysis is necessary. NAA is remarkably free of matrix effects essentially eliminating complex pre analysis procedures. It is uniquely suited to determining low levels of certain elements such as Cl, Br and I, particularly in organic samples. Its ability to determine sub-ppm levels of Cl in transformer oils has greatly assisted in the development of a patented method for the destruction of PCB ' s. It is possible to analyse large samples in order to overcome homogeneity problems, which is particularly useful in the precious metals industry. Radiochemical NAA enables the determination of very low levels of particular elements (eg Ta) in samples traditionally difficult to dissolve (author)

  1. Dead-time measurement of neutron counters by reactor-power variational technique

    International Nuclear Information System (INIS)

    Hashimoto, Kengo; Ohsawa, Takaaki

    1994-01-01

    The measurements of dead time of BF 3 , 3 He, fission and proton-recoil neutron counters were performed on the basis of the reactor-power variational technique in the reactor, UTR-KINKI reactor. The advantage of this method consists in making it possible to change the flux of irradiation field continuously and over a wide range. The reactor UTR-KINKI is well suited for the measurements since the power of the reactor can be easily changed and the range of flux is just appropriate to evaluate the dead time. The results indicate that the nonparalysable model for the dead time characteristics is applicable to the counters employed. The measured dead time of fission counter is about 1.4 μs, while those of others range of 6-9 μs. (author)

  2. Analysis of EBR-II neutron and photon physics by multidimensional transport-theory techniques

    International Nuclear Information System (INIS)

    Jacqmin, R.P.; Finck, P.J.; Palmiotti, G.

    1994-01-01

    This paper contains a review of the challenges specific to the EBR-II core physics, a description of the methods and techniques which have been developed for addressing these challenges, and the results of some validation studies relative to power-distribution calculations. Numerical tests have shown that the VARIANT nodal code yields eigenvalue and power predictions as accurate as finite difference and discrete ordinates transport codes, at a small fraction of the cost. Comparisons with continuous-energy Monte Carlo results have proven that the errors introduced by the use of the diffusion-theory approximation in the collapsing procedure to obtain broad-group cross sections, kerma factors, and photon-production matrices, have a small impact on the EBR-II neutron/photon power distribution

  3. Neutronics experiments, radiation detectors and nuclear techniques development in the EU in support of the TBM design for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Angelone, M., E-mail: maurizio.angelone@enea.it [ENEA UT-FUS C.R. Frascati, via E. Fermi, 45-00044 Frascati (Italy); Fischer, U. [Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Flammini, D. [ENEA UT-FUS C.R. Frascati, via E. Fermi, 45-00044 Frascati (Italy); Jodlowski, P. [AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow (Poland); Klix, A. [Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Kodeli, I. [Jožef Stefan Institute, Ljubljana (Slovenia); Kuc, T. [AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow (Poland); Leichtle, D. [Fusion for Energy, C/Josep Pla 2, Torres Diagonal Litoral B3, 08019 Barcelona (Spain); Lilley, S. [Culham Centre for Fusion Energy, Culham, OX14 3DB (United Kingdom); Majerle, M.; Novák, J. [Nuclear Physics Institute of the ASCR, Řež 130, 250 68 Řež (Czech Republic); Ostachowicz, B. [AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow (Poland); Packer, L.W. [Culham Centre for Fusion Energy, Culham, OX14 3DB (United Kingdom); Pillon, M. [ENEA UT-FUS C.R. Frascati, via E. Fermi, 45-00044 Frascati (Italy); Pohorecki, W. [AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow (Poland); Radulović, V. [Jožef Stefan Institute, Ljubljana (Slovenia); Šimečková, E. [Nuclear Physics Institute of the ASCR, Řež 130, 250 68 Řež (Czech Republic); and others

    2015-10-15

    Highlights: • A number of experiments and tests are ongoing to develop detectors and methods for HCLL and HCPM ITER-TBM. • Experiments for measuring gas production relevant to IFMIF are also performed using a cyclotron. • A benchmark experiment with a Cu block is performed to validate copper cross sections. • Experimental techniques to measure tritium in TBM are presented. • Experimental verification of activation cross sections for a Neutron Activation System for TBM is addressed. - Abstract: The development of high quality nuclear data, radiation detectors and instrumentation techniques for fusion technology applications in Europe is supported by Fusion for Energy (F4E) and conducted in a joint and collaborative effort by several European research associations (ENEA, KIT, JSI, NPI, AGH, and CCFE) joined to form the “Consortium on Nuclear Data Studies/Experiments in Support of TBM Activities”. This paper presents the neutronics activities carried out by the Consortium. A selection of available results are presented. Among then a benchmark experiment on a pure copper block to study the Cu cross sections at neutron energies relevant to fusion, the fabrication of prototype neutron detectors able to withstand harsh environment and temperature >200 °C (artificial diamond and self-powered detectors) developed for operating in ITER-TBM as well as measurement of relevant activation and integral gas production cross-sections. The latter measured at neutron energies relevant to IFMIF (>14 MeV) and the development of innovative experimental techniques for tritium measurement in TBM.

  4. Neutron beam applications - Development of single crystal structure analysis technique using the HANARO neutron four circle diffractometer

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-04-01

    As the four circle diffractometer (FCD) has been set up in HANARO, it has become possible to study the single crystal structures by means of the neutron diffraction. Taking account of the geometry of the FCD, a program for the control of te FCD and neutron data acquisition operating under Windows' circumstance has been accomplished. Also, a computer program which can automatically measure the diffraction intensity data has been developed. All data obtained from the FCD are processed automatically for further work and a software for the single crystal structure analyses has been prepared. A KC1 single crystal was selected as first test sample for a structure analysis had been successfully performed on the FCD using in-house developed program and accordingly their functionings with precision were confirmed. For regular single crystal diffraction experiments, the structure analyses of chrysoberyl and Zr(Y)0{sub 1.87} single crystals were performed using both neutron and X-ray diffraction methods, and the result showed that the neutron diffraction work is superior to the X-ray one from the viewpoint of certain crystallographic information obtainable only from the former one. 24 refs., 15 figs., 15 tabs. (Author)

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

    OpenAIRE

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

    2013-01-01

    The Long interval, Ultra-wide dynamic Pile-up free Neutron rem counter (LUPIN) is a novel detector initially developed for radiation protection purposes, specifically conceived for applications in pulsed neutron fields. The detector has a measurement capability varying over many orders of neutron burst intensity, from a single neutron up to thousands of interactions for each burst, without showing any saturation effect. Whilst LUPIN has been developed for applications in the radiation protect...

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

    International Nuclear Information System (INIS)

    Nigg, D.W.; Wemple, C.A.; Hartwell, J.K.; Harker, Y.D.; Venhuizen, J.R.; Risler, R.

    1997-12-01

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

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

    International Nuclear Information System (INIS)

    Macias Betanzos, L.R.

    1993-01-01

    The Neutron Diffraction technique, it's a helpful tool for the study of materials. The purpose, was to verify that such technique works with the Neutron Diffractometer of National Institute of Nuclear Research. The scope, is to study crystalline materials by the Neutron Diffraction Method, that means it completion with Bragg's Law. There exist a lot of diffraction techniques that depend on the kind of study to do. In this case the study was to measure known samples to have a correlation between parameters such a extinction factor and dislocation density. Known copper deformed samples were measured to observe the extinction effect and it could be observed. We had to calibrate the Neutron Diffractometer, the detection system and to have an optimal movement control of diffractometer devices by mean of a microcomputer. Also, was necessary to control the Reactor TRIGA operation to minimize the neutron flux oscillation. It was not possible the quantification of dislocation density in the samples because the relation signal/background was about one and it gives high inaccuracy. To correct this problem, it's necessary to have a better shielding to minimize the contribution of the background. The conclusion is that the Neutron Diffractometer is in conditions to carry out investigation on the material field, today it can be lattice constants, crystalline phases and measurements of metallic textures. For such studies, it's necessary to have samples with 2 cm 3 or higher to increase the relation signal/background. At present, we have the process software to give the interpretation of the Neutron Diffraction process. (Author). 12 refs, 16 figs

  8. Influence of design variations on controlled thermonuclear reactor blanket neutronic performance using variational techniques

    International Nuclear Information System (INIS)

    Cheng, E.T.; Conn, R.W.

    1977-01-01

    The influence of design variations, such as the percentage of structural material in a tritium breeding zone or the enrichment of lithium in 6 Li, on such important controlled thermonuclear reactor parameters as the tritium breeding ratio and the total nuclear energy produced has been studied using variational techniques for two different but general blanket designs. The first design uses liquid lithium as both coolant and breeding material, while the second uses a helium coolant and a solid-lithium-bearing compound as the tritium breeder. A variational technique based on variational interpolation is the primary computational tool, and it is shown that for linear perturbations in the transport operator and for a fixed source, only forward flux calculations are required to implement the variational interpolation approach. No adjoint functions are required to implement the variational interpolation approach. No adjoint functions are required, while any number of response functionals can be investigated. For both blanket designs, the influence of the choice of structural material, such as stainless-steel, molybdenum, niobium, vanadium, and aluminum structures, has been studied. The role of beryllium as a neutron multiplier with a solid breeder blanket is studied, and an optimum beryllium thickness is found that maximizes the breeding ratio. The influence of using graphite or the structural material as a neutron reflector and the effect of lithium burnup are also studied. It is found that for a given percentage of structural material in the tritium breeding zones, vanadium-structured systems achieve the highest breeding ratios, while molybdenum-structured systems produce the highest value of total nuclear heating. The effects of lithium burnup are small

  9. Application of the neutron noise technique for measurement of reactivity for subcritical reactor RA-4

    International Nuclear Information System (INIS)

    Orso, J; Marenzana, A

    2012-01-01

    Reactor core RA-4 is divided into two parts that come together to start reactor. The reactor with core separate has the largest subcritical condition, this condition is more secure and therefore the reactor shutdown. In this paper measurements are made of the decay constant of the neutron prompt ' P ', using the α-Rossi and α-Feynman methods to calculate the reactivity of the reactor core for different positions. Both techniques are compared and reactivity is obtained for several position of the reactor core using the α-Rossi technical which is obtained a function that gives the reactivity depending on the separation of the core length. Both techniques are verified using a no multiplicative system. Reactivity values for different position of the core obtained by α-Rossi technique are: $[0 cm] = (-11+/-1) dollar, $[3 cm] = (-7+/-1) dollar, $[3.5 cm] (-5.5+/-0.8) dollar, $[4.2 cm] = (-3.8+/-0.3) dollar y $[4.5] = (-3.0+/-0.1) dollar (author)

  10. Radiation absorbed from dental implant radiography: a comparison of linear tomography, CT scan, and panoramic and intra-oral techniques

    Energy Technology Data Exchange (ETDEWEB)

    Clark, D.E.; Danforth, R.A.; Barnes, R.W.; Burtch, M.L. (Loma Linda Univ., CA (USA))

    1990-01-01

    Absorbed radiation dose in bone marrow, thyroid, salivary gland, eye, and skin entrance was determined by placement of lithium fluoride thermoluminescent dosimeters (TLD's) at selected anatomical sites within and on a human-like x-ray phantom. The phantom was exposed to radiation from linear tomographic and computer-assisted tomographic (CT) simulated dental implant radiographic examinations. The mean dose was determined for each anatomical site. Resulting dose measurements from linear tomography and computer-assisted tomography are compared with reported panoramic and intra-oral doses. CT examination delivered the greatest dose, while linear tomography was generally lowest. Panoramic and intra-oral doses were similar to those of linear tomography.

  11. Neutron range spectrometer

    Science.gov (United States)

    Manglos, Stephen H.

    1989-06-06

    A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are collimnated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. The computer solves the following equation in the analysis: ##EQU1## where: N(x).DELTA.x=the number of neutron interactions measured between a position x and x+.DELTA.x, A.sub.i (E.sub.i).DELTA.E.sub.i =the number of incident neutrons with energy between E.sub.i and E.sub.i +.DELTA.E.sub.i, and C=C(E.sub.i)=N .sigma.(E.sub.i) where N=the number density of absorbing atoms in the position sensitive counter means and .sigma. (E.sub.i)=the average cross section of the absorbing interaction between E.sub.i and E.sub.i +.DELTA.E.sub.i.

  12. 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.

  13. Trace elements in California aerosols. Part I. Instrumental neutron activation analysis techniques

    International Nuclear Information System (INIS)

    Ragaini, R.C.; Ralston, H.R.; Garvis, D.; Kaifer, R.

    1975-01-01

    Instrumental Neutron Activation Analysis (INAA) done at LLL played a key role in the 1972--1974 California Aerosol Characterization Experiment (ACHEX), a major experiment in the chemistry of aerosols in urban and non-urban sites of California sponsored by the State of California Air Resources Board. The main purpose of INAA was to measure the particle size distributions and diurnal patterns of key chemical constituents in aerosols collected in California. These data were used to satisfy some of the key objectives of ACHEX, including aerosol characterization and evaluation of the origins and evolutions of aerosols. Secondary uses of INAA were the validations of the Lundgren rotating drum cascade impactors used in the ACHEX, and validations of other analytical techniques used in the chemical analyses. As a result of these studies, it was concluded that techniques using INAA were useful operational methods for chemical analysis of aerosols collected over two-hour periods in urban air with an active monitoring program. (U.S.)

  14. Review of personal monitoring techniques for the measurement of absorbed dose from external beta and low energy photon radiation

    DEFF Research Database (Denmark)

    Christensen, Poul

    1986-01-01

    The techniques available at present for personal monitoring of doses from external beta and low energy photon radiation are reviewed. The performance of currently used dosimetry systems is compared with that recommended internationally, and developments for improving the actual performance...

  15. Reducing the absorbed dose in analogue radiography of infant chest images by improving the image quality, using image processing techniques

    International Nuclear Information System (INIS)

    Karimian, A.; Yazdani, S.; Askari, M. A.

    2011-01-01

    Radiographic inspection is one of the most widely employed techniques for medical testing methods. Because of poor contrast and high un-sharpness of radiographic image quality in films, converting radiographs to a digital format and using further digital image processing is the best method of enhancing the image quality and assisting the interpreter in their evaluation. In this research work, radiographic films of 70 infant chest images with different sizes of defects were selected. To digitise the chest images and employ image processing the two algorithms (i) spatial domain and (ii) frequency domain techniques were used. The MATLAB environment was selected for processing in the digital format. Our results showed that by using these two techniques, the defects with small dimensions are detectable. Therefore, these suggested techniques may help medical specialists to diagnose the defects in the primary stages and help to prevent more repeat X-ray examination of paediatric patients. (authors)

  16. Fluence-to-absorbed-dose conversion coefficients for neutron beams from 0.001 eV to 100 GeV calculated for a set of pregnant female and fetus models

    International Nuclear Information System (INIS)

    Taranenko, Valery; Xu, X George

    2008-01-01

    Protection of fetuses against external neutron exposure is an important task. This paper reports a set of absorbed dose conversion coefficients for fetal and maternal organs for external neutron beams using the RPI-P pregnant female models and the MCNPX code. The newly developed pregnant female models represent an adult female with a fetus including its brain and skeleton at the end of each trimester. The organ masses were adjusted to match the reference values within 1%. For the 3 mm cubic voxel size, the models consist of 10-15 million voxels for 35 organs. External monoenergetic neutron beams of six standard configurations (AP, PA, LLAT, RLAT, ROT and ISO) and source energies 0.001 eV-100 GeV were considered. The results are compared with previous data that are based on simplified anatomical models. The differences in dose depend on source geometry, energy and gestation periods: from 20% up to 140% for the whole fetus, and up to 100% for the fetal brain. Anatomical differences are primarily responsible for the discrepancies in the organ doses. For the first time, the dependence of mother organ doses upon anatomical changes during pregnancy was studied. A maximum of 220% increase in dose was observed for the placenta in the nine months model compared to three months, whereas dose to the pancreas, small and large intestines decreases by 60% for the AP source for the same models. Tabulated dose conversion coefficients for the fetus and 27 maternal organs are provided

  17. Measurement of vortex motion in a type-II superconductor: A novel use of the neutron spin-echo technique

    Science.gov (United States)

    Forgan; Kealey; Johnson; Pautrat; Simon; Lee; Aegerter; Cubitt; Farago; Schleger

    2000-10-16

    We have used the neutron spin-echo technique to measure the small energy change of neutrons which are diffracted by a moving vortex lattice in a low-pinning Nb-Ta superconducting sample. A transport current was passed in the mixed state to cause flux line movement. In the case of uniform motion, the flux velocity v(L) was given as expected by the values of electric and magnetic fields, via E = -v(L)wedgeB. We show that with a nonuniformly moving vortex lattice, one can measure the dispersion of the velocities, opening up new possibilities for investigating moving vortex lines.

  18. Experimental techniques and theoretical models for the study of integral 14 MeV neutron cross sections

    International Nuclear Information System (INIS)

    Csikai, J.

    1981-01-01

    Owing to technical reasons, most of the data for fast neutron-induced reactions were measured at 14 MeV and the free parameters in nuclear reaction models have been determined at this energy. The discrepancies between experiment and theory are often due to the unmeasured or unreliable experimental data; therefore, it is important to survey the present techniques used for the measurement of total, elastic, nonelastic and partial nonelastic [(n,xn); (n,x charged); (n,f); (n,γ)] cross sections for 14 MeV neutrons. Systematics in the data as well as theoretical and semi-empirical models are also outlined. (author)

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

    International Nuclear Information System (INIS)

    Tjioe, P.S.; Goeij, J.J.M. de; Houtman, J.P.W.

    1976-09-01

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

  20. A comparison of analogue and digital techniques in upper gastrointestinal examinations: absorbed dose and diagnostic quality of the images

    International Nuclear Information System (INIS)

    Axelsson, B.; Hansson, I.B.; Boden, K.; Witt, H.H.; Fransson, S.G.; Persliden, J.

    2000-01-01

    This study was performed to investigate whether patient exposure and diagnostic quality of the image is significantly influenced by the introduction of digital image acquisition techniques. Evaluation was performed for three different techniques (analogue, analogue fluoro+digital radiography, digital) in examination of the upper gastrointestinal tract. The evaluation was done from data acquired in three different departments. Patient exposure was recorded as KERMA-area product (KAP) and the individual patient readings were normalised to a standard size patient. Image quality was assessed using visual grading with a reference image. The recorded KAP values were significantly higher (22.3 Gycm 2 ) for the fully digital technique compared to the others (analogue 6.8 Gycm 2 , analogue+digital 3.6 Gycm 2 ). This was due mostly to an increased number of exposures. The diagnostic quality of the image was, however, also regarded to be slightly lower for the technique giving the lowest patient dose with the smallest number of exposures (analogue+digital). The digital examination technique, as used in this study, thus resulted in significantly higher patient dose without any significant gain in diagnostic quality of the image. (orig.)

  1. 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.

  2. Segmental dynamics in polymer melts by relaxation techniques and quasielastic neutron scattering

    Science.gov (United States)

    Colmenero, J.

    1993-01-01

    The dynamics of the segmental α-relaxation in three different polymeric systems, poly(vinyl methy ether) (PVME), poly(vinyl chloride) (PVC) and poly(bisphenol A, 2-hydroxypropylether) (PH) has been studied by means of relaxation techniques and quasielastic neutron scattering (backscattering spectrometers IN10 and IN13 at the ILL-Grenoble). By using these techniques we have covered a wide timescale ranging from mesoscopic to macroscopic times (10-10-101s). For analyzing the experimental data we have developed a phenomenological procedure in the frequency domain based on the Havriliak-Negami relaxation function which in fact implies a Kohlrausch-Williams-Watts relaxation function in the time domain. The results obtained indicate that the dynamics of the α-relaxation in a wide timescale shows a clear non-Debye behaviour. The shape of the relaxation function is found to be similar for the different techniques used and independent of temperature and momentum transfer (Q). Moreover the characteristic relaxation times deduced from the fitting of the experimental data can also be described using only one Vogel-Fulcher functional form. Besides we found that the Q-dependence of the relaxation times obtained by QENS is given by a power law, τ(Q) propto Q-n (n > 2) n being dependent on the system, and that the Q-behaviour and the non-Debye behaviour are directly correlated. We discuss this correlation taking into account several data of the dynamics of the α-relaxation previously reported in the literature. We also outline a possible scenario for explaining this empirical correlation.

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

    International Nuclear Information System (INIS)

    Al-Aseery, Sh.M.; Alamoudi, Z.; Hassan, A.M.

    2006-01-01

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

  4. Sound Absorbers

    Science.gov (United States)

    Fuchs, H. V.; Möser, M.

    Sound absorption indicates the transformation of sound energy into heat. It is, for instance, employed to design the acoustics in rooms. The noise emitted by machinery and plants shall be reduced before arriving at a workplace; auditoria such as lecture rooms or concert halls require a certain reverberation time. Such design goals are realised by installing absorbing components at the walls with well-defined absorption characteristics, which are adjusted for corresponding demands. Sound absorbers also play an important role in acoustic capsules, ducts and screens to avoid sound immission from noise intensive environments into the neighbourhood.

  5. Pulsed-laser time-resolved thermal mirror technique in low-absorbance homogeneous linear elastic materials.

    Science.gov (United States)

    Lukasievicz, Gustavo V B; Astrath, Nelson G C; Malacarne, Luis C; Herculano, Leandro S; Zanuto, Vitor S; Baesso, Mauro L; Bialkowski, Stephen E

    2013-10-01

    A theoretical model for a time-resolved photothermal mirror technique using pulsed-laser excitation was developed for low absorption samples. Analytical solutions to the temperature and thermoelastic deformation equations are found for three characteristic pulse profiles and are compared to finite element analysis methods results for finite samples. An analytical expression for the intensity of the center of a continuous probe laser at the detector plane is derived using the Fresnel diffraction theory, which allows modeling of experimental results. Experiments are performed in optical glasses, and the models are fitted to the data. The parameters of the fit are in good agreement with previous literature data for absorption, thermal diffusion, and thermal expansion of the materials tested. The combined modeling and experimental techniques are shown to be useful for quantitative determination of the physical properties of low absorption homogeneous linear elastic material samples.

  6. Experimental validation of energy parameters in parabolic trough collector with plain absorber and analysis of heat transfer enhancement techniques

    Science.gov (United States)

    Bilal, F. R.; Arunachala, U. C.; Sandeep, H. M.

    2018-01-01

    The quantum of heat loss from the receiver of the Parabolic Trough Collector is considerable which results in lower thermal efficiency of the system. Hence heat transfer augmentation is essential which can be attained by various techniques. An analytical model to evaluate the system with bare receiver performance was developed using MATLAB. The experimental validation of the model resulted in less than 5.5% error in exit temperature using both water and thermic oil as heat transfer fluid. Further, heat transfer enhancement techniques were incorporated in the model which included the use of twisted tape inserts, nanofluid, and a combination of both for further enhancement. It was observed that the use of evacuated glass cover in the existing setup would increase the useful heat gain up to 5.3%. Fe3O4/H2O nanofluid showed a maximum enhancement of 56% in the Nusselt number for the volume concentration of 0.6% at highest Reynolds number. Similarly, twisted tape turbulators (with twist ratio of 2) taken alone with water exhibited 59% improvement in Nusselt number. Combining both the heat transfer augmentation techniques at their best values revealed the Nusselt number enhancement up to 87%. It is concluded that, use of twisted tape with water is the best method for heat transfer augmentation since it gives the maximum effective thermal efficiency amongst all for the range of Re considered. The first section in your paper

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-03-01

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

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

    International Nuclear Information System (INIS)

    Ueki, Kotaro

    1998-01-01

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

  9. Characterization of Nanocellulose Using Small-Angle Neutron, X-ray, and Dynamic Light Scattering Techniques.

    Science.gov (United States)

    Mao, Yimin; Liu, Kai; Zhan, Chengbo; Geng, Lihong; Chu, Benjamin; Hsiao, Benjamin S

    2017-02-16

    Nanocellulose extracted from wood pulps using TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation and sulfuric acid hydrolysis methods was characterized by small-angle neutron scattering (SANS), small-angle X-ray scattering (SAXS), and dynamic light scattering (DLS) techniques. The dimensions of this nanocellulose (TEMPO-oxidized cellulose nanofiber (TOCN) and sulfuric acid hydrolyzed cellulose nanocrystal (SACN)) revealed by the different scattering methods were compared with those characterized by transmission electron microscopy (TEM). The SANS and SAXS data were analyzed using a parallelepiped-based form factor. The width and thickness of the nanocellulose cross section were ∼8 and ∼2 nm for TOCN and ∼20 and ∼3 nm for SACN, respectively, where the fitting results from SANS and SAXS profiles were consistent with each other. DLS was carried out under both the V V mode with the polarizer and analyzer parallel to each other and the H V mode having them perpendicular to each other. Using rotational and translational diffusion coefficients obtained under the H V mode yielded a nanocellulose length qualitatively consistent with that observed by TEM, whereas the length derived by the translational diffusion coefficient under the V V mode appeared to be overestimated.

  10. Metallic Concentration in Karnaphuly Estuary Sediment Using Neutron Activation Analysis Technique

    International Nuclear Information System (INIS)

    Rahman, A.K.M.R.; Chakroborty, S.R.; Roy, P.K.; Dev, A.K.

    2013-01-01

    Thousands of tonnes of liquid waste, dirt and garbage from different mills and factories from Kaptai to Chittagong are dumped unhindered into the Karnaphuli River. Pollutants enter the river directly from urban sewerage and industrial waste discharges. Ships pollute waterways in many ways. All theses can contribute to the heavy and other metals of the water bodies. To find out concentration of different metallic elements and make a comparison with the world reference values twenty one surface sediment samples were collected from the different locations of Karnaphuly River near Chittagong city drainage outlet. Neutron Activation Analysis (NAA) technique was used for detecting the concentration qualitatively and quantitatively using the 3 MW TRIGA MARK II research reactor of Atomic Energy Research Establishment, Savar, Dhaka. Pearson correlation among the elements obtained using SPSS software. Three transitional metals Fe, Cr and Co, two alkali metals Rb and Na, two lanthanides La and Ce, and two metalloids As and Sb were determined. The concentrations of elements were compared with the world reference values. Some elements are found in elevated level. (author)

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

    International Nuclear Information System (INIS)

    Blostein, Juan Jeronimo

    2004-01-01

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

  12. A New Neutron Calibration Technique with Fast Scintillators on DIII-D Tokamak

    Science.gov (United States)

    Zhu, Y. B.; Heidbrink, W. W.; Taylor, P. L.; Carrig, W.

    2015-11-01

    Absolute calibrations are necessary for conventional neutron measurements based on proportional counters and fission chambers, at regular intervals. For the DIII-D tokamak, the wide span of fusion rates, approximately between 1.e9 - 1.e17 neutrons per second, from pure Ohmic to high power auxiliary heating plasmas requires careful cross-calibrations of a variety of neutron detectors with stepwise and overlapped sensitivities, with an intense isotope neutron source, e.g. californium-252 and real plasmas. Scintillators have been successfully utilized for fast time resolved neutron detection for decades. A new calibration approach with the help of scintillators is shown to be straightforward, simpler and trustworthy while the conventional approach is complicated, time consuming and costly. Details on the calibration setup and results will be presented. Supported by US DOE SC-G903402 and DE-FC02-04ER54698.

  13. Utilization of RP-10 reactor for neutron therapy

    International Nuclear Information System (INIS)

    Paucar, R.; Nieto, M.; Parreno, F.; Vela, M.; Pozo, Z.

    1997-01-01

    In the Nuclear Energy Peruvian Institute, IPEN, a research area has established of Neutron Radiotherapy, know as NCT. This research joins the physics of particles (Neutrons and photons) and Medical Physics, and this one is an applied investigation where in considering the construction of a treatment hall in Huarangal (Peru) Reactor's irradiation facility, it can treat patients with brain tumors. In Neutron Therapy (NCT), it tries to use neutrons to destroy tumor cells where other therapeutic techniques are not effective. This process consist on to incise a neutrons beam of adequate characteristics over the tumor area of the patient. The neutrons used are of thermal energy and therefore irradiations are developed in experimental reactors. For this one, it is used horizontal channels prepared suitably. Before the irradiation, it is injected to the patient a substance which is absorbed by tumoral tissue. The substance components will be B-10, nuclide with an absorption cross section high to thermal neutrons (3837 b). The B-10 irradiate with thermal neutrons produce alpha particles of short reach (10 μm. on soft tissue) and with LET values (lineal energy transference) very high. The result is a cell preferential destruction which have absorbed the substance and it's next neighbors, like the cell size is 10 μm. This process as know as Boron Neutron Capture Therapy (BNCT). This work describes Peruvian RP-10 reactor and recently efforts to assess the design and feasibility of the medical neutron irradiation facility for NCT. (author). 22 refs., 6 tabs

  14. Study of the dynamic and magnetic properties of solids using inelastic scattering and polarized neutron techniques. Part of a coordinated programme on the use of neutron scattering techniques in the study of solids

    International Nuclear Information System (INIS)

    Iyengar, P.

    1977-12-01

    Magnetic moment density distributions of several cubic spinel ferrites were obtained by using the neutron diffraction technique. The investigated materials were magnetite, MnFe 2 O 4 , MnAlGe, and Cu 2 MnAl. Information about the static and time-averaged behaviour of the magnetic electrons was deduced. The diffuse scattering technique with polarized neutrons which permits to isolate the magnon-scattering profile from other neutron profiles, was utilized to explore the acoustic magnon branches in ferro and ferrimagnetic materials such as MnFe 2 O 4 . The lattice and molecular dynamics has been studied in a number of condensed systems. Librational motions of water molecules in crystal hydrates were determined by the technique of polarization dependence of incoherent scattering cross section. Librations of amino and methyl groups in amino acids have been studied. Mixed salts of various ammonium and potassium compounds were investigated with a view to elucidate the nature of potential function and reorientational motions of reorienting ions

  15. Search for the existence of circulating currents in high-Tc superconductors using the polarized neutron scattering technique

    International Nuclear Information System (INIS)

    Sidis, Y.; Fauque, B.; Aji, V.; Bourges, P.

    2007-01-01

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

  16. Calculation of absorbed fractions to human skeletal tissues due to alpha particles using the Monte Carlo and 3-d chord-based transport techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, J.G. [Institute of Radiation Protection and Dosimetry, Av. Salvador Allende s/n, Recreio, Rio de Janeiro, CEP 22780-160 (Brazil); Watchman, C.J. [Department of Radiation Oncology, University of Arizona, Tucson, AZ, 85721 (United States); Bolch, W.E. [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL, 32611 (United States); Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611 (United States)

    2007-07-01

    Absorbed fraction (AF) calculations to the human skeletal tissues due to alpha particles are of interest to the internal dosimetry of occupationally exposed workers and members of the public. The transport of alpha particles through the skeletal tissue is complicated by the detailed and complex microscopic histology of the skeleton. In this study, both Monte Carlo and chord-based techniques were applied to the transport of alpha particles through 3-D micro-CT images of the skeletal microstructure of trabecular spongiosa. The Monte Carlo program used was 'Visual Monte Carlo-VMC'. VMC simulates the emission of the alpha particles and their subsequent energy deposition track. The second method applied to alpha transport is the chord-based technique, which randomly generates chord lengths across bone trabeculae and the marrow cavities via alternate and uniform sampling of their cumulative density functions. This paper compares the AF of energy to two radiosensitive skeletal tissues, active marrow and shallow active marrow, obtained with these two techniques. (authors)

  17. Application of neutron activation analysis technique in elemental determination of lichen samples

    International Nuclear Information System (INIS)

    Djoko Prakoso Dwi Atmodjo; Syukria Kurniawati; Woro Yatu Niken Syahfitri; Nana Suherman; Dadang Supriatna

    2010-01-01

    Lichen is one of the biological materials as pollution monitor that can give information about level, direction, and history of various pollutants in environment. Small sample weights and elemental content of lichens is on the order of ppm, so that its characterization requires advanced analytical techniques that has high sensitivity and capable of analyzing samples with weight of - 25 mg, such as neutron activation analysis. In this research, determination of elements was done in lichen samples obtained from Kiaracondong and Holis areas in Bandung city, to understanding the difference of industrial exposure level on surrounding environment. Samples were irradiated in RSG GA Siwabessy, Serpong, at 15 MW for 1-2 and 60 minutes for short irradiation and long irradiation, respectively. The samples were then counted using HPGe detector with GENIE 2000 software. The level of element in lichen for Kiaracondong area were Co, Cr, Cs, Fe, Mg, Mn, Sb, Sc, and V in the range of 0.55-0.86, 1.47-2.57, 0.87-1.19, 540-1005, 949-1674, 34.91-45.94, 0.08-0.14, 0.16-0.31, and ≤ 2.33 mg/kg, respectively, while for Holis area were 1.04-2.37, 4.41-10.36, 0.41-0.89, 3166-709, 1131-1422, 40.97-72.51, 0.33-0.50, 0.98-2.18, and 5.30-13.05 mg/kg respectively. From these results, it is known that pollution exposure from the semi industrial area Holis provide greater influence than in the semi industrial area Kiaracondong. (author)

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

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

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

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

    International Nuclear Information System (INIS)

    Mota, F.; Ortiz, C. J.; Vila, R.

    2012-01-01

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

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

    International Nuclear Information System (INIS)

    Zhou, T.; Hawari, A. I.; Wehring, B. W.

    2007-01-01

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

  1. Neutron diffraction

    International Nuclear Information System (INIS)

    Bacon, G.E.

    1983-01-01

    The paper reviews neutron diffraction work from the early studies to the present-day development of the subject. Direct structural investigations were described, including chemical applications associated with single crystal techniques, and magnetic applications identified with powder techniques. The properties of the neutron beams are discussed, as well as the use of polarised beams. (UK)

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

    International Nuclear Information System (INIS)

    Moraes, M.A.P.V. de; Pugliesi, R.; Khouri, M.T.F.C.

    1985-11-01

    The solid state nuclear track detectors technique has been used for determination of boron in aqueous solutions, using a filtered neutron beam. The particles tracks from the 10 B(n,α)Li 7 reaction were registered in the CR-39 film, chemically etched in a (30%) KOH solution 70 0 C during 90 minutes. The obtained results showed the usefulness of this technique for boron determination in the ppm range. The inferior detectable limit was 9 ppm. The combined track registration efficiency factor K has been evaluated in the solutions, for the CR-39 detector and its values is K= (4,60 - + 0,06). 10 -4 cm. (Author) [pt

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

    Science.gov (United States)

    Sakurai, Kenji

    2010-12-01

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

  4. A physical and engineering study on the irradiation techniques in neutron capture therapy aiming for wider application

    International Nuclear Information System (INIS)

    Sakurai, Y.; Ono, K.; Suzuki, M.; Katoh, I.; Miyatake, S.-I.; Yanagie, H.

    2003-01-01

    The solo-irradiation of thermal neutrons has been applied for brain cancer and malignant melanoma in the boron neutron capture therapy (BNCT) at the medical irradiation facility of Kyoto University Reactor (KUR), from the first clinical trial in 1974. In 1997, after the facility remodeling, the application of the mix-irradiation of thermal and epi-thermal neutrons was started, and the depth dose distribution for brain cancer has been improved in some degree. In 2001, the solo-irradiation of epi-thermal neutrons also started. It is specially mentioned that the application to oral cancers started at the same time. The BNCT clinical trial using epi-thermal neutron irradiation at KUR, amounts to twelve as of March 2003. The seven trials; more than a half of the total trials, are for oral cancers. From this fact, we think that the wider application to the other cancers is required for the future prosperity of BNCT. The cancers applied for BNCT in KUR at the present time, are brain cancer, melanoma and oral cancers, as mentioned above. The cancers, expected to be applied in near future, are liver cancer, pancreas cancer, lung cancer, tongue cancer, breast cancer, etc.. Any cancer is almost incurable by the other therapy including the other radiation therapy. In the wider application of BNCT to these cancers, the dose-distribution control suitable to each cancer and/or each part, is important. The introduction of multi-directional and/or multi-divisional irradiation is also needed. Here, a physical and engineering study using two-dimensional transport calculation and three-dimensional Monte-Carlo simulation for the irradiation techniques in BNCT aiming for wider application is reported

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

    CERN Document Server

    Glickstein, S S; Joo, H

    1999-01-01

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

  6. Refinement procedures of hydrogen and hydration structures of proteins by neutron diffraction technique

    International Nuclear Information System (INIS)

    Chatake, Toshiyuki; Morimoto, Yukio

    2007-01-01

    Neutrons have a unique role to play in determining the structure and dynamics of proteins and their complexes. Water molecules surrounding a protein play important roles in maintaining its structural stability. However, the hydration structures of most proteins are not known well at an atomic level because x-ray protein crystallography has difficulties to localize the position of hydrogen atoms, while neutron crystallography has not problem in determining the position of hydrogen atoms with high accuracy. A software suite, called Crystallography and NMR System (CNS), has been developed for macromolecular structure determinations by x-ray crystallography or solution nuclear magnetic resonance spectroscopy by A.T. Brunger et al. The software CNS is highly flexible, and is applied for neutron diffraction measurements after some modifications of parameters used in the software. The fundamental modifications are the followings; D atoms in replace of H atoms, and the substitution of neutron scattering lengths for x-ray scattering factors. Moreover, in neutron diffraction data analysis, an important problem rests on the introduction of hydrogen atoms into the software of x-ray crystallography without hydrogen atoms. After the above procedures, the software modified is applied to determine the molecular structure of histidine residue associated with hydrogen atoms. (author)

  7. Grazing incidence small-angle neutron scattering-an advanced scattering technique for the investigation of nanostructured polymer films

    Science.gov (United States)

    Müller-Buschbaum, P.; Gutmann, J. S.; Cubitt, R.; Petry, W.

    2004-07-01

    With grazing incidence small-angle neutron scattering (GISANS), the limitations of conventional small-angle neutron scattering with respect to extremely small sample volumes in the thin-film geometry are overcome. GISANS turned out to be a powerful advanced scattering technique for the investigation of nanostructured polymer films. Similar to atomic force microscopy the surface topography is probed. In addition, buried structures from inside the film are detectable. As an example of the actual limits, nanostructures resulting from destabilized diblock copolymer films of poly(styrene-block-paramethylstyrene) in the highly confined regime are investigated. The stability of the structure, introduced by toluene vapor treatment, against annealing above the micro-phase separation temperature is shown.

  8. Grazing incidence small-angle neutron scattering - an advanced scattering technique for the investigation of nanostructured polymer films

    International Nuclear Information System (INIS)

    Mueller-Buschbaum, P.; Gutmann, J.S.; Cubitt, R.; Petry, W.

    2004-01-01

    With grazing incidence small-angle neutron scattering (GISANS), the limitations of conventional small-angle neutron scattering with respect to extremely small sample volumes in the thin-film geometry are overcome. GISANS turned out to be a powerful advanced scattering technique for the investigation of nanostructured polymer films. Similar to atomic force microscopy the surface topography is probed. In addition, buried structures from inside the film are detectable. As an example of the actual limits, nanostructures resulting from destabilized diblock copolymer films of poly(styrene-block-paramethylstyrene) in the highly confined regime are investigated. The stability of the structure, introduced by toluene vapor treatment, against annealing above the micro-phase separation temperature is shown

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

    International Nuclear Information System (INIS)

    Sales, H.B.

    1981-08-01

    Boron content in water solutions has been analysed by Indirect Activation Technique a twin 241 Am/Be neutron source with a source strength of 9x10 6 n/seg. The boron concentration was inferred from the measurement of the activity induced in a vanadium flux monitor. The vanadium rod was located inside the boron solution in a standart geometrical set up with respect to the neutron source. Boron concentrations in the range of 100 to 1000 ppm were determined with an overall accuracy of about 2% during a total analysis time of about 20 minutes. Eventhough the analysis is not selective for boron yet due the rapid, simple and precise nature, it is proposed for the analysis of boron in the primary coolant circuit of Nuclear Power Plants of PWR type. (Author) [pt

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

    International Nuclear Information System (INIS)

    Zhang Yangmei; Ni Bangfa; Wang Pingsheng; Tian Weizhi; Cao Lei

    2001-01-01

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

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

    Science.gov (United States)

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

    2015-02-01

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

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

    International Nuclear Information System (INIS)

    Colognesi, D.; Pietropaolo, A.; Senesi, R.; Ramirez-Cuesta, A. J.

    2007-01-01

    Inelastic neutron scattering experiments were performed at intermediate and high momentum transfers, up to 85-90 A ring -1 , to study the proton momentum distribution in polycrystalline sodium hydrogen fluoride (NaHF 2 ) at low temperature (below 5 K). The H mean kinetic energy was extracted and compared to the results from hydrogen-projected density of phonon states derived from intermediate momentum transfer inelastic neutron scattering and lattice dynamics simulations. A reasonable agreement between the two figures was found. In addition, relevant aspects of high momentum transfer neutron scattering from NaHF 2 were explored in detail, ranging from an alternative evaluation of final state effects to the role played by the instrumental resolution and to the possibility to reconstruct the potential felt by a proton from its momentum distribution

  13. Kinetic calculations for miniature neutron source reactor using analytical and numerical techniques

    International Nuclear Information System (INIS)

    Ampomah-Amoako, E.

    2008-06-01

    The analytical methods, step change in reactivity and ramp change in reactivity as well as numerical methods, fixed point iteration and Runge Kutta-gill were used to simulate the initial build up of neutrons in a miniature neutron source reactor with and without temperature feedback effect. The methods were modified to include photo neutron concentration. PARET 7.3 was used to simulate the transients behaviour of Ghana Research Reactor-1. The PARET code was capable of simulating the transients for 2.1 mk and 4 mk insertions of reactivity with peak powers of 49.87 kW and 92.34 kW, respectively. PARET code however failed to simulate 6.71 mk of reactivity which was predicted by Akaho et al through TEMPFED. (au)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-07-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-15

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

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

    International Nuclear Information System (INIS)

    Campo B, X.; Mendez V, R.; Embid S, M.; Vega C, H. R.; Sanz G, J.

    2014-08-01

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

  17. On the sensitivity evaluation for on-stream elemental analysis using neutron and photoactivation techniques

    International Nuclear Information System (INIS)

    Ivanov, I.N.; Zakharov, E.A.; Kasatkin, V.A.; Kartashev, E.R.; Mashinin, V.A.; Feoktistov, Yu.V.; Tchulkin, V.L.

    1984-01-01

    The paper discusses the data of calculations of neutron and photonactivation effects of moving substances, in particular, bulk materials moving on a conveyor belt and solution streams. The calculated data on minimum detectable concentrations of the various elements are given. The calculation data satisfactorily agree with the experimental data obtained as a result of on-stream neutron activation analysis of solutions containing indium, selenium, aluminium, fluorine and also bulk materials containing aluminium and silicon. The opportunity of applying the bremsstrahlung generated by the electron accelerator for photon activation analysis and sorting gold-bearing ores on the conveyor belt has been analysed

  18. Development of the delyed-neutron triangulation technique for locating failed fuel in LMFBR

    International Nuclear Information System (INIS)

    Kryter, R.C.

    1975-01-01

    Two major accomplishments of the ORNL delayed neutron triangulation program are (1) an analysis of anticipated detector counting rates and sensitivities to unclad fuel and erosion types of pin failure, and (2) an experimental assessment of the accuracy with which the position of failed fuel can be determined in the FFTF (this was performed in a quarter-scale water mockup of realistic outlet plenum geometry using electrolyte injections and conductivity cells to simulate delayed-neutron precursor releases and detections, respectively). The major results and conclusions from these studies are presented, along with plans for further DNT development work at ORNL for the FFTF and CRBR. (author)

  19. Neutron time-of-flight measurement techniques: new possibilities of TOF spectroscopy with NEAT at BENSC

    CERN Document Server

    Ruffle, B; Longeville, S; Lechner, R E

    2000-01-01

    A series of experiments performed on the TOF spectrometer NEAT at the Berlin Neutron Scattering Center is reported to demonstrate the versatility and some of the original possibilities offered by this instrument: continuous variation of the energy resolution over four decades, TOF diffraction using single detectors and a large range of incident neutron wavelengths, high-resolution studies in (Q, omega)-space of single crystals with a multidetector at large scattering angle, or elastic and inelastic small-angle scattering with the multidetector at zero angle.

  20. The detection of landmines by neutron backscattering: Exploring the limits of the technique

    International Nuclear Information System (INIS)

    Viesti, G.; Lunardon, M.; Nebbia, G.; Barbui, M.; Cinausero, M.; D'Erasmo, G.; Palomba, M.; Pantaleo, A.; Obhodas, J.; Valkovic, V.

    2006-01-01

    Neutron backscattering (NB) sensors have been proposed for Humanitarian De-mining applications. Recently, a prototype hand-held system integrating a NB sensor in a metal detector has been developed within the EU-funded DIAMINE Project. The results obtained in terms of performance of the NB systems and limitations in its use are presented in this work. It is found that the performance of NB sensors is strongly limited by the presence of the soil moisture and by its small-scale variations. The use of the neutron hit distribution to reduce false alarms is explored

  1. Comparison of quartz crystallographic preferred orientations identified with optical fabric analysis, electron backscatter and neutron diffraction techniques.

    Science.gov (United States)

    Hunter, N J R; Wilson, C J L; Luzin, V

    2017-02-01

    Three techniques are used to measure crystallographic preferred orientations (CPO) in a naturally deformed quartz mylonite: transmitted light cross-polarized microscopy using an automated fabric analyser, electron backscatter diffraction (EBSD) and neutron diffraction. Pole figure densities attributable to crystal-plastic deformation are variably recognizable across the techniques, particularly between fabric analyser and diffraction instruments. Although fabric analyser techniques offer rapid acquisition with minimal sample preparation, difficulties may exist when gathering orientation data parallel with the incident beam. Overall, we have found that EBSD and fabric analyser techniques are best suited for studying CPO distributions at the grain scale, where individual orientations can be linked to their source grain or nearest neighbours. Neutron diffraction serves as the best qualitative and quantitative means of estimating the bulk CPO, due to its three-dimensional data acquisition, greater sample area coverage, and larger sample size. However, a number of sampling methods can be applied to FA and EBSD data to make similar approximations. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

  2. Absorber materials in CANDU PHWR's

    International Nuclear Information System (INIS)

    Price, E.G.; Boss, C.R.; Novak, W.Z.; Fong, R.W.L.

    1995-03-01

    In a CANDU reactor the fuel channels are arranged on a square lattice in a calandria filled with heavy water moderator. This arrangement allows five types of tubular neutron absorber devices to be located in a relatively benign environment of low pressure, low temperature heavy water between neighbouring rows of columns of fuel channels. This paper will describe the roles of the devices and outline the design requirements of the absorber component from a reactor physics viewpoint. Nuclear heating and activation problems associated with the different absorbers will be briefly discussed. The design and manufacture of the devices will be also discussed. The control rod absorbers and shut off materials are cadmium and stainless steel. In the tubular arrangement, the cadmium is sandwiched between stainless steel tubes. This type of device has functioned well, but there is now concern over the availability and expense of cadmium which is used in two types of CANDU control devices. There are also concerns about the toxicity of cadmium during the fabrication of the absorbers. These concerns are prompting AECL to study alternatives. To minimize design changes, pure boron-10 alloyed in stainless steel is a favoured option. Work is underway to confirm the suitability of the boron-loaded steel and identify other encapsulated absorber materials for practical application. Because the reactivity devices or their guide tubes span the calandria vessel, the long slender components must be sufficiently rigid to resist operational vibration and also be seismically stable. Some of these components are made of Zircaloy to minimize neutron absorption. Slow irradiation growth and creep can reduce the spring tension, and periodic adjustments to the springs are required. Experience with the control absorber devices has generally been good. In one instance liquid zone controllers had a problem of vibration induced fretting but a designed back-fit resolved the problem. (author). 3 refs., 1

  3. Feasibility of calibration of liquid sodium flowmeters by neutron activation techniques

    International Nuclear Information System (INIS)

    Kehler, P.

    1976-07-01

    Velocities of fluids in pipes can be measured by injecting radioactive tracers into the fluid and recording the activity downstream of the injection point. One convenient method of injecting radioactive tracers is by neutron activation of the fluid itself. The present report describes a FORTRAN program that can be used for the prediction of the counting rates of fluid flow tests performed with a pulsed neutron source and a scintillation detector. The program models the flow profile and the mixing of the fluid, the attenuation of neutrons and gamma rays in the fluid, and the geometric arrangement of the source and the detector. Using this program, an experiment for the measurement of the secondary sodium flow of the EBR-II was optimized. A pulsed D,T neutron source and a 5 in. x 5 in. NaI detector will be used in the EBR-II test. Under optimized conditions, the expected accuracy of the flow measurement is about 2 percent

  4. A new technique for the calibration of neutron probes by volumetric method

    International Nuclear Information System (INIS)

    Encarnacao, F.A.F. da.

    1988-01-01

    Laboratory and field studies were performed for the determination of a calibration curve of a neutron probe in three different kinds of soils: Red Yellow PODZOLIC, LITOLIC and ALLUVIAL, in the last one laboratory studies were done to determine local humidity on the calibration curve parameters. (A.C.A.S.) [pt

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

    NARCIS (Netherlands)

    Maucec, M

    2005-01-01

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

  6. A comparison in the reconstruction of neutron spectrums using classical iterative techniques

    International Nuclear Information System (INIS)

    Ortiz R, J. M.; Martinez B, M. R.; Vega C, H. R.; Gallego, E.

    2009-10-01

    One of the key drawbacks to the use of BUNKI code is that the process begins the reconstruction of the spectrum based on a priori knowledge as close as possible to the solution that is sought. The user has to specify the initial spectrum or do it through a subroutine called MAXIET to calculate a Maxwellian and a 1/E spectrum as initial spectrum. Because the application of iterative procedures by to resolve the reconstruction of neutron spectrum needs an initial spectrum, it is necessary to have new proposals for the election of the same. Based on the experience gained with a widely used method of reconstruction, called BUNKI, has developed a new computational tools for neutron spectrometry and dosimetry, which was first introduced, which operates by means of an iterative algorithm for the reconstruction of neutron spectra. The main feature of this tool is that unlike the existing iterative codes, the choice of the initial spectrum is performed automatically by the program, through a neutron spectra catalog. To develop the code, the algorithm was selected as the routine iterative SPUNIT be used in computing tool and response matrix UTA4 for 31 energy groups. (author)

  7. Feasibility of activation techniques for neutron measurements in the NET-blanket

    International Nuclear Information System (INIS)

    Bertalot, L.; Pillon, M.

    1987-07-01

    A feasibility study has been carried out on the diagnostical possibilities offered by local activation probes of measuring the neutron fluxes, fluences and energy spectra in various locations inside the NET (Next European Tours) device. Three sets of 12 candidate materials/reactions have been selected for the first wall, outboard blanket, and outboard shield positions for irradiation within a single plasma discharge

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

    International Nuclear Information System (INIS)

    Lehmann, E.; Pleinert, H.; Williams, T.; Pralong, C.

    1999-01-01

    The demands on modern irradiation detection systems are diverse, encompassing spatial resolution, dynamic range, sensitivity and reproducibility. Nevertheless, there are two important new methods which can satisfy most of these demands in several applications: camera based systems and imaging plates. Imaging plates have primarily been used as γ- and β-sensitive detectors in biology and medicine, but are now available also as neutron sensitive systems. These methods are ideally suited for applications in neutron radiography because of their high sensitivity, linearity and digital output. Image processing, quantification of the image data and automated pattern recognition can easily be performed using modern software tools. The imaging plate system at PSI is shared between groups in reactor physics, radiation protection, biology, proton therapy and nuclear medicine. The collected experience from these different interests establishes the basis for a most effective application of this technique. The utilisation of detector systems based on CCD-cameras have other advantages, like low acquisition time, high frame rates, reproducibility as well as high dynamic range. These detectors are applied to investigations of time dependent processes, distribution analyses and quantitative studies. The new radiography facility NEUTRA at the spallation source SINQ provides excellent conditions for neutron radiography studies. Some first examples of investigations with imaging plates and the CCD-camera system are given

  9. Real-time small-angle neutron scattering techniques probing sub-millisecond dynamics in magnetic nanomaterials

    International Nuclear Information System (INIS)

    Wiedenmann, A.; Gaehler, R.; Dewhurst, C.; Keiderling, U.; Prevost, S.; Kohlbrecher, J.

    2010-01-01

    Stroboscopic Small Angle Neutron Scattering (SANS) techniques have recently been developed which allow ordering and relaxation processes of magnetic moments in nano-particles to be monitored. By applying a periodic external magnetic field the time-resolved SANS response to a forced oscillation could be analyzed. Here we present results from stroboscopic measurements on nanoscaled materials such as Cobalt ferrofluids and solid alloys by using polarised neutrons. SANS scattering response in an oscillating magnetic field was measured as a function of temperature, frequency and amplitude of the applied field. The fraction of superparamagnetic moments that can follow the oscillating field produces scattering patterns alternating between fully isotropic and strongly anisotropic. When the relaxation time of the ferrofluid to get in thermal equilibrium wit an applied magnetic field becomes similar to the period of the oscillating magnetic field one expects a phase shift and a damping in the magnetic response of the ferrofluid particles. To measure these polarized neutrons with polarisation analysis (POLARIS) are of great advantage

  10. A novel Fe–Cr–Nb matrix composite containing the TiB2 neutron absorber synthesized by mechanical alloying and final hot isostatic pressing (HIP) in the Ti-tubing

    International Nuclear Information System (INIS)

    Litwa, Przemysław; Perkowski, Krzysztof; Zasada, Dariusz; Kobus, Izabela; Konopka, Gustaw; Czujko, Tomasz; Varin, Robert A.

    2016-01-01

    The Fe–Cr–Ti-Nb elemental powders were mechanically alloyed/ball milled with TiB 2 and a small quantity of Y 2 O 3 ceramic to synthesize a novel Fe-based alloy-ceramic powder composite that could be processed by hot isostatic pressing (HIP) for a perceived potential application as a neutron absorber in nuclear reactors. After ball milling for the 30–80 h duration relatively uniform powders with micrometric sizes were produced. With increasing milling time a fraction of TiB 2 particles became covered with the much softer Fe-based alloy which resulted in the formation of a characteristic “core-mantel” structure. For the final HIP-ing process the mechanically alloyed powders were initially uniaxially pressed into rod-shaped compacts and then cold isostatically pressed (CIP-ed). Subsequently, the rod-shaped compacts were placed in the Ti-tubing and subjected to hot isostatic pressing (HIP) at 1150 °C/200 MPa pressure. The HIP-ing process resulted in the formation of the near-Ti and intermediate diffusional layers in the microstructure of HIP-ed samples which formed in accord with the Fe-Ti binary phase diagram. Those layers contain the phases such as α-Ti (HCP), the FeTi intermetallic and their hypo-eutectoid mixtures. In addition, needle-like particles were formed in both layers in accord with the Ti-B binary phase diagram. Nanohardness testing, using a Berkovich type diamond tip, shows that the nanohardness in the intermediate layer areas, corresponding to the composition of the hypo-eutectoid mixture of Ti-FeTi, equals 980.0 (±27.1) HV and correspondingly 1176.9 (±47.6) HV for the FeTi phase. The nanohardness in the sample's center in the areas with the fine mixture of Fe-based alloy and small TiB 2 particles equals 1048.3 (±201.8) HV. The average microhardness of samples HIP-ed from powders milled for 30 and 80 h is 588 HV and 733 HV, respectively. - Highlights: • A Fe–Cr–Nb-based composite with TiB 2 neutron absorbing ceramic was

  11. High resolution neutron tomography applied to tooth fillings on real teeth by use of neutron lens

    International Nuclear Information System (INIS)

    Masschaele, B.; Cauwels, P.; Mondelaers, W.; Baechler, S.; Jolie, J.; Materna, T.

    2000-01-01

    Today tomography is a well known technique for nondestructive analysis of samples. By taking several X-ray pictures from an object, it is possible to make a 3D reconstruction. The same thing can be done with neutrons. Since very recent it is possible to produce a high-flux neutron beam. By looking at the attenuation of the neutron beam in the sample from different angles, it is possible to make a neutron tomography. The properties of neutrons are so much different from X-rays that a new era in tomography has started. Where X-rays have a hard time penetrating samples containing heavy elements (Pb, Bi, U, Hg, Au), neutrons just seem to walk through. But when the neutrons encounter samples containing light compounds like water, oil, paper, B, Li,... they are easily absorbed. This makes the use of neutrons for imaging complementary to the well known X-ray imaging. The most used tooth filling material nowadays is amalgam. Amalgam is a mixture of different metals, like silver, tin, copper, mercury. Mercury is dangerous for the human body when it enters the blood stream. These fillings are very dense and X-rays have a very hard time penetrating it. Neutrons are the ideal probe for investigation of these high density regions. The result of the tomography reveals information on the long term stability of amalgam fillings and could help the still ongoing debate on the safety of the fillings. (author)

  12. Use of the neutron diffraction - H/D exchange technique to determine the conformational dynamics of trypsin

    International Nuclear Information System (INIS)

    Kossiakoff, A.A.

    1982-01-01

    Reported here are studies analyzing the extent and nature of the inherent conformational fluctuations in trypsin by neutron diffraction - hydrogen exchange techniques. The pattern of exchange investigates systematic relationships between exchangeable sites and the structural and chemical properties of the molecule. Our findings that pH 7, 20 0 and 1 year of soaking all sites of trypsin are fully exchanged except those which are especially well protected by the structure. Essentially all the sites in which the peptide hydrogens are bonded directly to water molecules - either in the bulk solvent regions or in interior clusters - are fully exchanged. 41 references, 10 figures

  13. Determination of silver, gold, zinc and copper in mineral samples by various techniques of instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Rodriguez R, N. I.; Rios M, C.; Pinedo V, J. L.; Yoho, M.; Landsberger, S.

    2015-09-01

    Using the method of instrumental neutron activation analysis, mineral exploration samples were analyzed in order to determine the concentrations of silver, gold, zinc and copper; these minerals being the main products of benefit of Tizapa and Cozamin mines. Samples were subjected to various techniques, where the type of radiation and counting methods were chosen based on the specific isotopic characteristics of each element. For calibration and determination of concentrations the comparator method was used, certified standards were subjected to the same conditions of irradiation and measurement that the prospecting samples. The irradiations were performed at the research reactor TRIGA Mark II of the University of Texas at Austin. The silver concentrations were determined by Cyclical Epithermal Neutron Activation Analysis. This method in combination with the transfer pneumatic system allowed a good analytical precision and accuracy in prospecting for silver, from photo peak measurement 657.7 keV of short half-life radionuclide 110 Ag. For the determination of gold and zinc, Epithermal Neutron Activation Analysis was used, the photo peaks analyzed corresponded to the energies 411.8 keV of radionuclide 199 Au and 438.6 keV of metastable radionuclide 69m Zn. On the other hand, copper quantification was based on the photo peak analysis of 1039.2 keV produced by the short half-life radionuclide 66 Cu, by Thermal Neutron Activation Analysis. The photo peaks measurement corresponding to gold, zinc and copper was performed using a Compton suppression system, which allowed an improvement in the signal to noise relationship, so that better detection limits and low uncertainties associated with the results were obtained. Comparing elemental concentrations the highest values in silver, zinc and copper was for samples of mine Tizapa. Regarding gold values were found in the same range for both mines. To evaluate the precision and accuracy of the methods used, various geological

  14. Detection of microorganisms in culture medium through the neutron radiographic technique

    International Nuclear Information System (INIS)

    Wacha, Reinaldo

    1999-05-01

    The study aims to obtain a more effective and faster method for the detection of bacteria in several culture media, such as potable water and blood. After the process growth in the culture medium, separation and suspension in buffer solution based in boron, the bacteria are deposited in track detectors that are submitted to thermal neutron beams (neutron flux: 2,2 x 10 5 n.cm -2 .s -1 ), resulting from the channel J-9 of the Argonauta research reactor, from the Nuclear Engineering Institute, IEN/CNEN. The latent tracks arisen from the alpha particles proceeding from the reaction B (η, α) Li and, after having been revealed, are analyzed by an optical microscope that allows to detect the existence of the bacteria. Afterwards, they were analyzed in a nanoscope which helps the identification of the tracks of the alpha particles. (author)

  15. Retinue of the beans roots growth by using neutron radiography technique

    International Nuclear Information System (INIS)

    Jesus, Selma Parente de; Crispim, Verginia Reis

    2002-01-01

    Agricultural practices frequently cause the development of a soil compacted layer below the surface. These compacted layers restrict the root penetration into deeper layers of soil, in search for water. It is proposed to monitor, using Non Destructive Test, the roots growth due to the planting of standard seeds in different agricultural soils, in function of their compactness and humidity. It will be used the neutrons beams derived from an irradiation channel called J-9 of the Reactor Argonauta (IEN/CNEN), so that the neutron radiographic images of the soil-plant system can be obtained. Each root can be evaluated for its ability to penetrate into compacted soil layers; this fact would mean an optimization of agricultural harvests. (author)

  16. Neutron activation analysis as a tracer technique for evaluating sample dissolution methods

    International Nuclear Information System (INIS)

    Porritt, P.M.; Porritt, R.E.J.

    1978-01-01

    The usefulness of neutron activation analysis for monitoring sample dissolution methods has been demonstrated. Lanthanum was determined in the USGS standard rock GSP-1 by instrumental neutron activation analysis to provide a reference figure. When an irradiated sample of GSP-1 was sintered with sodium peroxide and the sinter cake washed with water, all the lanthanum-140 could be dissolved in dilute hydrochloric acid. Heating an irradiated sample of GSP-1 with a mixture of hydrofluoric acid, nitric acid and perchloric acid and evaporating to fumes of perchloric acid dissolved only 80% of the lanthanum-140. However, evaporation to dryness, addition of perchloric acid and reevaporation to dryness rendered all the lanthanum-140 soluble

  17. Performance of flowing sample neutron activation analysis technique for determination of multi-elemental content

    International Nuclear Information System (INIS)

    Mohamed Soliman; Mohamed, N.M.A.; Osman, A.M.; Abdel-Monem, A.M.

    2014-01-01

    In order to measure and obtain reliable data about elements via measuring of short-lived isotopes in liquid samples using neutron activation analysis, experiments have been carried out using a flowing sample neutron activation analysis method. During this work the performance and reliability for the proposed method have been tested using synthetic multi elements liquid samples. The radionuclide, associated elements and their concentration level have been measured using a counting system with a fixed dead-time. An HPGe spectrometry system was used to determine the most important γ-ray energies and intensities of these isotopes. The obtained results demonstrated the reliability and accuracy (bias <5 % and zeta score <2) of the tested method for determination the elemental content of liquid samples. (author)

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

    NARCIS (Netherlands)

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

    2009-01-01

    Until recently fabrication techniques of Renaissance bronzes have been studied only with the naked eye, microscopically, videoscopically and with X-radiography. These techniques provide information on production techniques, yet much important detail remains unclear. As part of an interdisciplinary

  19. Study of heterogeneous multiplying and non-multiplying media by the neutron pulsed source technique; Etude des milieux heterogenes multiplicateurs et non-multiplicateurs par la technique de la source pulsee de neutrons

    Energy Technology Data Exchange (ETDEWEB)

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

    1968-06-01

    The pulsed neutron technique consists essentially in sending in the medium to be studied a short neutron pulse and in determining the asymptotic decay constant of the generated population. The variation of the decay constant as a function of the size of the medium allows the medium characteristics to be defined. This technique has been largely developed these last years and has been applied as well to moderator as to multiplying media, in most cases homogeneous ones. We considered of interest of apply this technique to lattices, to see if useful informations could be collected for lattice calculations. We present here a general theoretical study of the problem, and results and interpretation of a series of experiments made on graphite lattices. There is a good agreement for non-multiplying media. In the case of multiplying media, it is shown that the age value used until now in graphite lattices calculations is over-estimated by about 10 per cent. [French] La technique de la pulsation neutronique consiste essentiellement a envoyer dans le milieu a etudier une courte bouffee de neutrons et a determiner la constante de decroissance asymptotique de la population engendree. La variation de cette constante de decroissance en fonction des dimensions du milieu permet de determiner ses caracteristiques. Cette technique a connu ces dernieres annees un grand essor et a ete appliquee a des moderateurs et des milieux multiplicateurs. Il s'agissait dans la plupart des cas de milieux homogenes. Il nous a semble interessant de l'utiliser dans le cas des reseaux, afin de voir si ces experiences peuvent fournir des renseignements utiles aux calculs. Nous presentons ici une etude theorique generale du probleme, ainsi que les resultats et l'interpretation d'une serie d'experiences faites sur des reseaux a graphite. L'accord est bon dans le cas des reseaux non-multiplicateurs. Dans le cas des reseaux multiplicateurs, on montre que la valeur de l

  20. NCT-ART - a neutron computer tomography code based on the algebraic reconstruction technique

    International Nuclear Information System (INIS)

    Krueger, A.

    1988-01-01

    A computer code is presented, which calculates two-dimensional cuts of material assemblies from a number of neutron radiographic projections. Mathematically, the reconstruction is performed by an iterative solution of a system of linear equations. If the system is fully determined, clear pictures are obtained. Even for an underdetermined system (low number of projections) reasonable pictures are reconstructed, but then picture artefacts and convergence problems occur increasingly. (orig.) With 37 figs [de

  1. Observation of oxygen Frenkel disorder in uranium dioxide above 2000 K using neutron scattering techniques

    International Nuclear Information System (INIS)

    Clausen, K.; Hayes, W.; Macdonald, J.E.; Osborn, R.; Hutchings, M.T.

    1983-12-01

    Diffraction and coherent diffuse quasielastic scattering of neutrons have been used to investigate Frenkel disorder of the oxygen sublattice in single crystals of stoichiometric UO 2 . Measurements were made up to 2900 K using a special high-temperature furnace. The results provide the first direct evidence for the occurrence of Frenkel disorder in UO 2 and enable estimates of the defect concentration and activation energy to be made. (author)

  2. Deformation processes in functional materials studied by in-situ neutron diffraction and ultrasonic techniques

    Czech Academy of Sciences Publication Activity Database

    Šittner, Petr; Novák, Václav; Landa, Michal; Lukáš, Petr

    2007-01-01

    Roč. 462, - (2007), s. 12-22 ISSN 0921-5093 R&D Projects: GA AV ČR IAA1048107; GA ČR GA106/03/1073 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z10480505; CEZ:AV0Z20760514 Keywords : in situ neutron diffraction * ultrasonics * SMA * NiTi * phase transformations Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.457, year: 2007

  3. A newly developed technique of wireless remote controlled visual inspection system for neutron guides of cold neutron research facilities at HANARO

    International Nuclear Information System (INIS)

    Huh, Hyung; Cho, Yeong Garp; Kim, Jong In

    2012-01-01

    KAERI developed a neutron guide system for cold neutron research facilities at HANARO from 2003 to 2010. In 2008, the old plug shutter and instruments were removed, and a new plug and primary shutter were installed as the first cold neutron delivery system at HANARO. At the beginning of 2010, all the neutron guides and accessories had been successfully installed as well. The neutron guide system of HANARO consists of the in pile plug assembly with in pile guides, the primary shutter with in shutter guides, the neutron guides in the guide shielding room with secondary shutter, and the neutron guides in the neutron guide hall. Three kinds of glass materials were selected with optimum lengths by considering their lifetime, shielding, maintainability and cost as well. Radiation damage of the guides can occur on the coating and glass by neutron capturing in the glass. It is a big challenge to inspect a guide failure because of the difficult surrounding environment, such as high level radiation, limited working space, and massive hard work for removing and reinstalling the shielding blocks as shown in Fig 1. Therefore, KAERI has developed a wireless remote controlled visual inspection system for neutron guides using an infrared light camera mounted on the vehicle moving in the guide

  4. Determination of hydrogen content of Jatropha biodiesel oil using neutron reflection technique

    International Nuclear Information System (INIS)

    Okunade, I. O.; Jonah, S. A.; Omede, M.

    2014-01-01

    Biofuel is an environmental-friendly alternative to fossil fuel and holds immense potential for the future energy needs of the country. Non-edible jatropha biodiesel oil has been identified as one of the suitable bio-fuel options. In this work, experimental measurements were performed to determine the total hydrogen content of jatropha oil and jatropha-synthetic diesel oil mixture. The work was carried out using a neutron reflection facility at the Centre for Energy Research and Training, Ahmadu Bello University, Zaria. Jatropha oil and jatropha-synthetic diesel mixture were subjected to experimental measurements for the purpose of determining bulk hydrogen content using neutron reflection facility that had been previously calibrated using various hydrocarbon materials of known hydrogen content. The hydrogen content of the sample were subsequently determined using their measured neutron reflection coefficient values and calibration data. In general, results obtained indicate high hydrogen content range of 10.68-12.16wt% for jatropha oil and the various jatropha-synthetic diesel mixtures. The implication of this is that jatropha oil or jatrophal-synthetic diesel mixture can be used as alternative fuel to mitigate high carbon monoxide emission.

  5. Application of the neutron activation analysis technique in trace elements analysis

    International Nuclear Information System (INIS)

    Khamis, I.; Sarheel, A.; Al-Somel, N.

    2006-12-01

    The main objective in this study is the implementation k 0 -standardization method (single comparator method) using gold comparator as a routine method in neutron activation analysis laboratory in Engineering Nuclear Department. Cadmium ratio Rcd; Cd-ratio = [A s p/(A s p) C d] and the nuclear reactor constants (f=φ t h/φ e pi subcadimum thermal- to- epithermal neutron flux ratio and α with describing the φ e (E)∼ 1/E 1+α neutron flux distribution) were determined in the inner and outer irradiation sites at MNS Reactor. K 0 -IAEA software, which provided by the Agency, has been installed and applied in our laboratory. Trace elements in many kinds of samples (biological, environmental, alloy ...etc) were determined using K 0 -IAEA software. The results of standard reference materials (SRM's) obtained in this work show a good agreement with the certified values, and we got these results with a good accuracy closer to results which we got from relative NAA method. (author)

  6. 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.)

  7. Monte Carlo simulations of elemental imaging using the neutron-associated particle technique.

    Science.gov (United States)

    Abel, Michael R; Nie, Linda H

    2018-02-06

    The purpose of this study is to develop and employ a Monte Carlo (MC) simulation model of associated particle neutron elemental imaging (APNEI) in order to determine the three-dimensional (3D) imaging resolution of such a system by examining relevant physical and technological parameters and to thereby begin to explore the range of clinical applicability of APNEI to fields such as medical diagnostics, intervention, and etiological research. The presented APNEI model was defined in MCNP by a Gaussian-distributed and isotropic surface source emitting deuterium + deuterium (DD) neutrons, iron as the target element, nine iron-containing voxels (1 cm 3 volume each) arranged in a 3-by-3 array as the interrogated volume of interest, and finally, by high-purity germanium (HPGe) gamma-ray detectors anterior and posterior to the 9-voxel array. The MCNP f8 pulse height tally was employed in conjunction with the PTRAC particle tracking function to not only determine the signal acquired from iron inelastic scatter gamma-rays but also to quantitate each of the nine target voxels' contribution to the overall iron signal - each detected iron inelastic scatter gamma-ray being traced to the source neutron which incited its emission. With the spatial, vector, and timing information of the series of events for each relevant neutron history as collected by PTRAC, realistic grayscale images of the distribution of iron concentration in the 9-voxel array were simulated in both the projective and depth dimensions. With an overall 225 ps timing resolution, 6.25 mm 2 imaging plate pixels assumed to have well localized scintillation, and a DD neutron, Gaussian-distributed source spot with a diameter of 2 mm, projective and depth resolutions of imaging resolution offered by APNEI of target elements such as iron lends itself to potential applications in disease diagnosis and treatment planning (high resolution) as well as to ordnance and contraband detection (low resolution). However

  8. Single crystal time-of-flight neutron diffraction of Cr3Si and MnF2: Comparison with monochromatic beam techniques

    International Nuclear Information System (INIS)

    Jauch, W.; Schultz, A.J.

    1987-01-01

    Single-crystal time-of-flight (TOF) neutron diffraction data have been collected for Cr 3 Si and MnF 2 with the Argonne Intense Pulsed Neutron Source. The purpose of this study was to test the accuracy of the TOF technique by a comparison with results from recent γ-ray, X-ray and neutron diffraction experiments. The results show that for simple crystal structures the positional and thermal parameters obtained from TOF data approach those obtained by other diffraction methods. (orig.)

  9. Comparison of neutron activation analysis techniques for the determination of uranium concentrations in geological and environmental materials

    International Nuclear Information System (INIS)

    Landsberger, S.; Kapsimalis, R.

    2013-01-01

    We have described the determination of uranium in environmental, geological, and agricultural specimens by three different non-destructive nuclear methods. The effectiveness, as defined as the lower limits of detection in this work, of quantifying trace levels of bulk uranium in geological samples was evaluated for several common NAA techniques. These techniques include short-lived and medium-lived neutron activation analysis using thermal and epithermal neutrons; these results were compared with an assessment of Compton suppressed gamma-ray counting. A careful evaluation of three major (n,γ) reactions with chlorine, manganese and sodium that could impede determining low levels of uranium due to high Compton continuums was done. The evaluation of Compton suppressed passive gamma counting revealed that uranium concentrations below 50 mg kg −1 were not adequate to achieve good counting statistics using the 234m Pa the second daughter product of 238 U. -- Highlights: ► Determination of uranium concentrations in geological, environmental, and agricultural specimens. ► Use of several NAA and passive counting methods. ► Identified several key interferences. ► Use of Compton suppression to minimize effects of interferences

  10. Particle Imaging Velocimetry Technique Development for Laboratory Measurement of Fracture Flow Inside a Pressure Vessel Using Neutron Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Polsky, Yarom [ORNL; Bingham, Philip R [ORNL; Bilheux, Hassina Z [ORNL; Carmichael, Justin R [ORNL

    2015-01-01

    This paper will describe recent progress made in developing neutron imaging based particle imaging velocimetry techniques for visualizing and quantifying flow structure through a high pressure flow cell with high temperature capability (up to 350 degrees C). This experimental capability has great potential for improving the understanding of flow through fractured systems in applications such as enhanced geothermal systems (EGS). For example, flow structure measurement can be used to develop and validate single phase flow models used for simulation, experimentally identify critical transition regions and their dependence on fracture features such as surface roughness, and study multiphase fluid behavior within fractured systems. The developed method involves the controlled injection of a high contrast fluid into a water flow stream to produce droplets that can be tracked using neutron radiography. A description of the experimental setup will be provided along with an overview of the algorithms used to automatically track droplets and relate them to the velocity gradient in the flow stream. Experimental results will be reported along with volume of fluids based simulation techniques used to model observed flow.

  11. Neutron and gamma-ray transmission technique for the on-line determination of moisture in coal and coke

    International Nuclear Information System (INIS)

    Sowerby, B.D.; Millen, M.J.; Rafter, P.T.

    1985-01-01

    A fast neutron and gamma-ray transmission technique is being developed for the on-line analysis of moisture in coal and coke. The technique utilises 252 Cf and 137 Cs sources and 3 He and NaI(Tl) detectors. Laboratory measurements on single coal samples have shown that moisture can be determined to better than 1 wt% over the range 0 to 16 wt% moisture and 5 to 17cm thickness. Reduced errors were obtained for restricted ranges of moisture and thickness. Preliminary measurements on coke of thickness 30 to 50cm have shown that moisture can be determined to within 0.26 wt% over the range 1 to 16 wt% moisture

  12. Application of sensitivity analysis to a simplified coupled neutronic thermal-hydraulics transient in a fast reactor using Adjoint techniques

    International Nuclear Information System (INIS)

    Gilli, L.; Lathouwers, D.; Kloosterman, J.L.; Van der Hagen, T.H.J.J.

    2011-01-01

    In this paper a method to perform sensitivity analysis for a simplified multi-physics problem is presented. The method is based on the Adjoint Sensitivity Analysis Procedure which is used to apply first order perturbation theory to linear and nonlinear problems using adjoint techniques. The multi-physics problem considered includes a neutronic, a thermo-kinetics, and a thermal-hydraulics part and it is used to model the time dependent behavior of a sodium cooled fast reactor. The adjoint procedure is applied to calculate the sensitivity coefficients with respect to the kinetic parameters of the problem for two reference transients using two different model responses, the results obtained are then compared with the values given by a direct sampling of the forward nonlinear problem. Our first results show that, thanks to modern numerical techniques, the procedure is relatively easy to implement and provides good estimation for most perturbations, making the method appealing for more detailed problems. (author)

  13. Experimental and mathematical simulation techniques for determining an in-situ response testing method for neutron sensors used in reactor power plant protection systems

    International Nuclear Information System (INIS)

    Behbahani, A.

    1983-01-01

    An analytical neutron sensor response model and methods for transient response measurements of neutron sensors (compensated ionization chamber), including possible in-situ techniques have been developed and evaluated to meet the provisions of Draft Standard ISA Sd67.06, IEEE 338-1977, and NRC Guide 1.118. One in-situ method requires the perturbation of the high voltage detector (sensor) power supply and measurement of the sensor response. The response to a perturbation of the power supply is related to the response of the sensor to a transient change in neutron flux. Random signal analysis is another in-situ technique to monitor the neutron sensor response. In this method the power spectrum of the inherent fluctuations from the neutron sensor output (current in CIC) are measured and evaluated. Transient response techniques (including in-situ methods) are experimentally and analytically evaluated to identify the mechanisms which may cause degradation in the response of the neutron sensors. The objective of the experimental evaluation was to correlate the measured response time using transient radiation flux changes and power supply perturbation. The objective of the analytical model of the different sensor response was to predict response time and degradation mechanisms

  14. High-temperature studies of UO2 and ThO2 using neutron scattering techniques

    International Nuclear Information System (INIS)

    Hutchings, M.T.

    1987-01-01

    A review of the results of recent neutron diffraction, coherent diffuse and inelastic scattering experiments on UO 2 and ThO 2 at temperatures between 293 K and 2930 K is given. These provide direct evidence for thermally induced Frenkel oxygen lattice disorder at temperatures > 2000 K and give data on the lattice expansion, ionic potentials and elastic stiffness constants to 2930 K for the first time. The results are important for an understanding of the thermophysical behaviour of UO 2 and contribute to the data base of thermodynamic properties of UO 2 . (author)

  15. Measurement techniques of magnetic properties for evaluation of neutron irradiation damage on austenitic stainless steels

    International Nuclear Information System (INIS)

    Yamagata, Ichiro; Konno, Shotaro; Hayashi, Takehiro; Takaya, Shigeru

    2012-01-01

    The remote-controlled equipment for measurement of magnetic flux density has been developed in order to evaluate the irradiation damage of austenitic stainless steels. Magnetic flux densities by neutron irradiation in austenitic stainless steels, SUS304 and Fast Breeder Reactor grade type 316 (316FR), have been measured by the equipment. The results show that irradiation damage affected to magnetic flux density, and indicate the measuring method of magnetic flux density using a small magnetizer with a permanent magnet of 2 mm in diameter is less affected by specimen shape. (author)

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

    DEFF Research Database (Denmark)

    Vickery, Anette; Deen, P. P.

    2014-01-01

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

  17. Neutronic density perturbation by probes

    International Nuclear Information System (INIS)

    Vigon, M. A.; Diez, L.

    1956-01-01

    The introduction of absorbent materials of neutrons in diffuser media, produces local disturbances of neutronic density. The disturbance depends especially on the nature and size of the absorbent. Approximated equations which relates te disturbance and the distance to the absorbent in the case of thin disks have been drawn. The experimental comprobation has been carried out in two especial cases. In both cases the experimental results are in agreement with the calculated values from these equations. (Author)

  18. Neutron reflectometry

    DEFF Research Database (Denmark)

    Klösgen-Buchkremer, Beate Maria

    2014-01-01

    Neutron (and X-ray) reflectometry constitute complementary interfacially sensitive techniques that open access to studying the structure within thin films of both soft and hard condensed matter. Film thickness starts oxide surfaces on bulk substrates, proceeding to (pauci-)molecular layers and up...... to hundreds of nanometers. Thickness resolution for flat surfaces is in the range of few Ǻngstrøm, and as a peculiar benefit, the presence and properties of buried interfaces are accessible. Focus here will be on neutron reflectometry, a technique that is unique in applications involving composite organic...... 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...

  19. Optimization of the indirect at neutron activation technique for the determination of boron in aqueous solutions

    International Nuclear Information System (INIS)

    Luz, L.C.Q.P. da.

    1984-01-01

    The purpose of this work was the development of an instrumental method for the optimization of the indirect neutron activation analysis of boron in aqueous solutions. The optimization took into account the analytical parameters under laboratory conditions: activation carried out with a 241 Am/Be neutron source and detection of the activity induced in vanadium with two NaI(Tl) gamma spectrometers. A calibration curve was thus obtained for a concentration range of 0 to 5000 ppm B. Later on, experimental models were built in order to study the feasibility of automation. The analysis of boron was finally performed, under the previously established conditions, with an automated system comprising the operations of transport, irradiation and counting. An improvement in the quality of the analysis was observed, with boron concentrations as low as 5 ppm being determined with a precision level better than 0.4%. The experimental model features all basic design elements for an automated device for the analysis of boron in agueous solutions wherever this is required, as in the operation of nuclear reactors. (Author) [pt

  20. Phase Concentration Determination of Fe16N2 Using State of the Art Neutron Scattering Techniques

    Science.gov (United States)

    Bennett, S. P.; Feygenson, M.; Jiang, Y.; Zande, B. J.; Zhang, X.; Sankar, S. G.; Wang, J. P.; Lauter, V.

    2016-06-01

    Due to limitations on the availability of rare earth elements it is imperative that new high energy product rare earth free permanent magnet materials are developed for the next generation of energy systems. One promising low cost permanent magnet candidate for a high energy magnet is α″-Fe16N2, whose giant magnetic moment has been predicted to be well above any other from conventional first principles calculations. Despite its great promise, the α″ phase is metastable; making synthesis of the pure phase difficult, resulting in less than ideal magnetic characteristics. This instability gives way to a slew of possible secondary phases (i.e. α-Fe, Fe2O3, Fe8N, Fe4N, etc.) whose concentrations are difficult to detect by conventional x-ray diffraction. Here we show how high resolution neutron diffraction and polarized neutron reflectometry can be used to extract the phase concentration ratio of the giant magnetic phase from ultra-small powder sample sizes (~0.1 g) and thin films. These studies have led to the discovery of promising fabrication methods for both homogeneous thin films, and nanopowders containing the highest reported to date (>95%) phase concentrations of room temperature stable α″-Fe16N2.

  1. In vivo monitoring of toxic metals: assessment of neutron activation and x-ray fluorescence techniques

    International Nuclear Information System (INIS)

    Ellis, K.J.

    1986-01-01

    To date, cadmium, lead, aluminum, and mercury have been measured in vivo in humans. The possibilities of monitoring other toxic metals have also been demonstrated, but no human studies have been performed. Neutron activation analysis appears to be most suitable for Cd and Al measurements, while x-ray fluorescence is ideally suited for measurement of lead in superficial bone. Filtered neutron beams and polarized x-ray sources are being developed which will improve in vivo detection limits. Even so, several of the current facilities are already suitable for use in epidemiological studies of selected populations with suspected long-term low-level ''environmental'' exposures. Evaluation and diagnosis of patients presenting with general clinical symptoms attributable to possible toxic metal exposure may be assisted by in vivo examination. Continued in vivo monitoring of industrial workers, especially follow-up measurements, will provide the first direct assessment of changes in body burden and a direct measure of the biological life-times of these metals in humans. 50 refs., 4 figs., 2 tabs

  2. Application of Thin Layer Activation Technique for Wear and Corrosion Studies in Stainless Steel Using Neutron Sources

    International Nuclear Information System (INIS)

    Mohamed, R.F.I.

    2013-01-01

    In this work elemental analysis for three types of stainless steel samples was performed to compare between their compositions. First the stainless samples were analyzed using Energy Dispersive X-ray (EDX) Spectrometer and Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) as conventional tools for elemental analysis. Second, the samples were subjected to detailed neutron activation analysis (NAA) using Pu-Be neutron source with applying γ-rays spectroscopic measurements for the irradiated samples. The first sample was in the form of thin foils. Eight radioactive isotopes were detected in the measured spectra namely 56 Mn, 59 Fe, 58 Co, 60 Co, 24 Na, 187 W, 99 Mo and 51 Cr which resulted from different neutron reactions with this sample. The other two samples were commercial and the NAA results for one of them show that all of the elements reported in the foil sample are the same except the absence of Mo and the presence of Cr.On the other hand the third sample shows a different composition where only Mn, Fe, and Ni were identified from the measured γ- ray spectra. Stacks of irradiated stainless steal foil and pellets were measured to obtain the activity as a function of thickness using the most intense gamma ray lines of the produced radionuclides. The obtained linear activity-thickness relations for the measured radionuclides were fitted to determine the slope and the maximum thickness which can be measured by this technique. The comparison between these curves showed that the most sensitive radioisotope for detecting slight changes in the thickness is 51 Cr which is formed through the 50 Cr (n,γ) 51 Cr reaction.

  3. Dynamics of the α-relaxation in glass-forming polymers. Study by neutron scattering and relaxation techniques

    Science.gov (United States)

    Colmenero, J.

    1993-12-01

    The dynamics of the α-relaxation in three different polymeric systems, poly(vinyl methyl ether) (PVME), poly(vinyl chloride) (PVC) and poly(bisphenol A, 2-hydroxypropylether) (PH) has been studied by means of relaxation techniques and quasielastic neutron scattering (backscattering spectrometers IN10 and IN13 at the ILL-Grenoble). By using these techniques we have covered a wide time scale ranging from mesoscopic to macroscopic times (10 -10 -10 1 s). For analyzing the experimental data we have developed a phenomenological procedure in the frequency domain based on the Havriliak-Negami relaxation function, which in fact implies a Kohlrausch-Williams-Watts relaxation function in the time domain. The results obtained indicate that the dynamics of the α-relaxation in a wide time scale shows a clear non-Debye behaviour. The shape of the relaxation functions is found to be similar for the different techniques used and independent of temperature and momentum transfer ( Q). Moreover, the characteristic relaxation times deduced from the fitting of the experimental data can also be described using only one Vogel-Fulcher functional form. Besides we found that the Q-dependence of the relaxation times obtained by QENS is given by a power law, τ( Q) ∞ Q- n ( n>2), n being dependent on the system, and that the Q-behaviour and the non-Debye behaviour are directly correlated. In the case of PVC, time of flight (TOF) neutron scattering experiments confirm these results in a shorter time scale (2×10 -11 -2× 10 -12 s). Moreover, TOF results also suggest the possibility of interpreting the “fast process” usually detected in glass-forming systems as a Debye-like short regime of the α-relaxation.

  4. Determination of Residual Stresses and Mechanical Properties using Neutron, X-ray Diffraction, Micro- and Nanoindentation Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, Cecilia

    2003-12-01

    The existence of residual stresses in engineering materials can significantly affect subsequent lifetime by augmenting or impeding failure. Consequently, for an accurate assessment of engineering lifetimes, there is a need to quantify residual stresses. Furthermore, knowledge of the origin of these stresses in conjunction with mechanical properties such as hardness and fracture toughness, among others, can be used to improve functionality by tailoring the microstructure through processing. In this work, neutron, x-ray diffraction, micro- and nanoindentation techniques were used for residual stress determination and mechanical characterization of WC-Co functionally graded composites, a Co-based Haynes 25 alloy weld, compressed steel and compacted Fe-brass powders. The neutron and x-ray diffraction techniques were used to assess residual strains and stresses while the instrumented indentation techniques were used to determine hardness, fracture toughness and elastic modulus. In each of these engineering materials, valuable insight relating to the overall mechanical performance was obtained. X-ray diffraction was used to determine thermal residual stresses that develop in a functionally graded WC-Co composite, commonly used as tool bits. Microstresses in the graded zone were attributed to the thermal mismatch between WC and the Co phase. The compressive macrostresses were determined to be a result of the compositional gradient. Micro- and nanoindentation experiments were used to determine hardness as a function of depth in two WC-Co functionally graded materials (FGMs). A relationship between hardness and Co phase content was established and explained for the two graded and five homogeneous samples. An experimental and simulation study of residual stresses was made in the vicinity of a gas tungsten arc weld in a Co-based Haynes 25 alloy used in a satellite component. The experimental measurements were made by neutron diffraction on the recently commissioned

  5. The analysis of pre-hispanic obsidians by the neutron activation technique

    International Nuclear Information System (INIS)

    Esparza L, R.; Tenorio C, D.; Jimenez R, M.

    2005-01-01

    The project called Bank of Data of the locations of obsidian of the occident of Mexico (Analysis by Neutron activation) as it has been explained, for the use of the Neutron activation analysis in archaeological materials it was developed from the years 1960. In Mexico it use is unfortunately very later, until the middle of the decade of 1990 the first studies were made. Without a doubt we face a bigger challenge which consists on creating databases of different materials to have comparison parameters of the studied materials. In the foreigner's different institutions (Missouri Research Reactor, University of Berkeley, among other) it has been of great importance the possibility to be able to compare the databases of each investigation with other coming from different institutions. The results to that have arrived even present certain error margin using the same study patterns, for what is advisable to only use own databases; for it, in the project of this investigation it is sought that the Nuclear Center has its own wealth of information of the different obsidian locations that they exist in the Mexican territory, so that later on the reliable analysis of materials coming from different archaeological places is made to know its origin. Thirteen obsidian locations were analyzed that are located in the states of Michoacan, Jalisco, Guanajuato and Zacatecas. The geologic samples were obtained of different investigation projects, of the National Institute of Anthropology and History, of the Center of Meso-American Studies and of Central America (CEMCA) and of the New Orleans University. One of the problems that face when studying the obsidian locations in the occident of Mexico is linked with the variety of colors that they exist in different locations. With it, we want to show the difficulty that it exists to study this material at level 'eye meter', that which could carry errors and graft of the archaeological information. It is for that reason that it becomes

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

    International Nuclear Information System (INIS)

    Hughes, D.J.; Koukovini-Platia, E.; Heeley, E.L.

    2014-01-01

    Highlights: • Residual stresses were determined in a welded EUROFER blanket assembly with integrated cooling channels. • Good agreement was seen between experimentally determined and predicted stresses. • We show that microstructure changes that occur in EUROFER steels during welding must be considered for residual stress determination. • An experimental route is proposed for validation of predicted stresses in reactor components using non-destructive diffraction techniques. - Abstract: Whilst the structural integrity and lifetime considerations in welded joints for blanket modules can be predicted using finite element software, it is essential to prove the validity of these simulations. This paper provides detailed analysis for the first time, of the residual stress state in a laser-welded sample with integral cooling channels. State-of-the-art non-destructive neutron diffraction was employed to determine the triaxial stress state and to understand microstructural changes around the heat affected zone. Synchrotron X-ray diffraction was used to probe the variation of strain-free lattice reference parameter around the weld zone allowing correction of the neutron measurements. This paper details an important experimental route to validation of predicted stresses in complex safety-critical reactor components for future applications

  7. Elemental analysis and plant samples at el-Manzala lake by neutron activation analysis technique

    International Nuclear Information System (INIS)

    Eissa, E.A.; Rofail, N.B.; Abdel-Haleem, A.S.; El-Abbady, W.H.; Hassan, A.M.

    1995-01-01

    A soil and a plant samples were taken from two locations, Bahr el-Bakar and Bahr Kados at the Manzala lake, where a high pollution is expected. The samples were especially treated and prepared for investigation by thermal neutron activation analysis (NAA). The irradiation facilities of the first egyptian research reactor (ET-R R-1) and the hyper pure germanium (HPGe) detection system were used for such a type of analysis. Among the 34 identified elements Fe, Co, As, Ru, Cd, Te, La, Sm, Eu, Tb, Hg, Th, and U are of a special significance because of their toxic deleterious impact to organisms. This work is a part of a research project concerning pollution studies on the river nile and some lakes of egypt. The data obtained in the present work stand as a reference basic record for any future follow up of the contamination level. 1 tab

  8. The application of computer technique in routine neutron activation analysis using high resolution gamma ray spectrometry

    International Nuclear Information System (INIS)

    Szopa, Z.; Plejewska, M.; Staszelis, J.

    1982-01-01

    A full system of four computer programs for routine - qualitative and quantitative - neutron activation analysis (NAA) using high resolution gamma ray-spectrometry had been elaborated. The structure and possibilities of the ''data flow'' programs i.e. programs DIDPDP and DIDCDC, dedicated for fast and reliable ''off line'' data transfer between the buffer memory of the spectrometric line (9-track magnetic tape) and the fast access memory (disc) of the used computers PDP-11/45 and CYBER-73 had been presented. The structure and organization of the ''data processing'' programs i.e. programs SAWAPS and MAZYG had been presented as well. The utility and reliability of these programs in the case of the large-scale, routine NAA, exampled by analysis of filters with air polutants, had been tested and discussed. Programs are written mainly in FORTRAN. (author)

  9. Characterization of porous materials using combined small-angle X-ray and neutron scattering techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Naiping; Borkar, Neha; Kohls, Doug; Schaefer, Dale W. (UCIN)

    2014-09-24

    A combination of ultra small angle X-ray scattering (USAXS) and ultra small angle neutron scattering (USANS) is used to characterize porous materials. The analysis methods yield quantitative information, including the mean skeletal chord length, mean pore chord length, skeletal density, and composition. A mixed cellulose ester (MCE) membrane with a manufacturer-labeled pore size of 0.1 {mu}m was used as a model to elucidate the specifics of the method. Four approaches describing four specific scenarios (different known parameters and form of the scattering data) are compared. Pore chords determined using all four approaches are in good agreement with the scanning electron microscopy estimates but are larger than the manufacturer's nominal pore size. Our approach also gives the average chord of the skeletal solid (struts) of the membrane, which is also consistent for all four approaches. Combined data from USAXS and USANS gives the skeletal density and the strut composition.

  10. Characterization of porous materials using combined small-angle X-ray and neutron scattering techniques

    International Nuclear Information System (INIS)

    Hu, Naiping; Borkar, Neha; Kohls, Doug; Schaefer, Dale W.

    2012-01-01

    A combination of ultra small angle X-ray scattering (USAXS) and ultra small angle neutron scattering (USANS) is used to characterize porous materials. The analysis methods yield quantitative information, including the mean skeletal chord length, mean pore chord length, skeletal density, and composition. A mixed cellulose ester (MCE) membrane with a manufacturer-labeled pore size of 0.1 μm was used as a model to elucidate the specifics of the method. Four approaches describing four specific scenarios (different known parameters and form of the scattering data) are compared. Pore chords determined using all four approaches are in good agreement with the scanning electron microscopy estimates but are larger than the manufacturer's nominal pore size. Our approach also gives the average chord of the skeletal solid (struts) of the membrane, which is also consistent for all four approaches. Combined data from USAXS and USANS gives the skeletal density and the strut composition.

  11. Neutron detection by scintillation of noble-gas excimers

    Science.gov (United States)

    McComb, Jacob Collin

    Neutron detection is a technique essential to homeland security, nuclear reactor instrumentation, neutron diffraction science, oil-well logging, particle physics and radiation safety. The current shortage of helium-3, the neutron absorber used in most gas-filled proportional counters, has created a strong incentive to develop alternate methods of neutron detection. Excimer-based neutron detection (END) provides an alternative with many attractive properties. Like proportional counters, END relies on the conversion of a neutron into energetic charged particles, through an exothermic capture reaction with a neutron absorbing nucleus (10B, 6Li, 3He). As charged particles from these reactions lose energy in a surrounding gas, they cause electron excitation and ionization. Whereas most gas-filled detectors collect ionized charge to form a signal, END depends on the formation of diatomic noble-gas excimers (Ar*2, Kr*2,Xe* 2) . Upon decaying, excimers emit far-ultraviolet (FUV) photons, which may be collected by a photomultiplier tube or other photon detector. This phenomenon provides a means of neutron detection with a number of advantages over traditional methods. This thesis investigates excimer scintillation yield from the heavy noble gases following the boron-neutron capture reaction in 10B thin-film targets. Additionally, the thesis examines noble-gas excimer lifetimes with relationship to gas type and gas pressure. Experimental data were collected both at the National Institute of Standards and Technology (NIST) Center for Neutron Research, and on a newly developed neutron beamline at the Maryland University Training Reactor. The components of the experiment were calibrated at NIST and the University of Maryland, using FUV synchrotron radiation, neutron imaging, and foil activation techniques, among others. Computer modeling was employed to simulate charged-particle transport and excimer photon emission within the experimental apparatus. The observed excimer

  12. Magnetic field evolution of neutron stars - I. Basic formalism, numerical techniques and first results

    Science.gov (United States)

    Bransgrove, Ashley; Levin, Yuri; Beloborodov, Andrei

    2018-01-01

    In this work we explore the evolution of magnetic fields inside strongly magnetized neutron stars in axisymmetry. We model numerically the coupled field evolution in the core and the crust. Our code models the Hall drift and Ohmic effects in the crust, the back-reaction on the field from magnetically induced elastic deformation of the crust, the magnetic twist exchange between the crust and the core, and the drift of superconducting flux tubes inside the core. The correct hydromagnetic equilibrium is enforced in the core. We find that (i) The Hall attractor found by Gourgouliatos and Cumming in the crust exists also for configurations when the B-field penetrates into the core. However, the evolution time-scale for the core-penetrating fields is dramatically different from that of the fields confined to the crust. (ii) The combination of Jones' flux tube drift and Ohmic dissipation in the crust can deplete the pulsar magnetic fields on the time-scale of 150 Myr if the crust is hot (T ∼ 2 × 108 K), but acts on much slower time-scales for cold neutron stars, such as recycled pulsars (∼1.8 Gyr, depending on impurity levels). (iii) The outward motion of superfluid vortices during the rapid spin-down of a young highly magnetized pulsar can result in a partial expulsion of flux from the core when B ≲ 1013 G. However for B ≳ 2 × 1013 G, the combination of a stronger magnetic field and a longer spin period implies that the core field cannot be expelled.

  13. Coupled neutronic-thermal-hydraulics analysis in a coolant subchannel of a PWR using CFD techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Felipe P.; Su, Jian, E-mail: sujian@nuclear.ufrj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear

    2017-07-01

    The high capacity of Computational Fluid Dynamics code to predict multi-dimensional thermal-hydraulics behaviour and the increased availability of capable computer systems are making that method a good tool to simulate phenomena of thermal-hydraulics nature in nuclear reactors. However, since there are no neutron kinetics models available in commercial CFD codes to the present day, the application of CFD in the nuclear reactor safety analyses is still limited. The present work proposes the implementation of the point kinetics model (PKM) in ANSYS - Fluent to predict the neutronic behaviour in a Westinghouse Sequoyah nuclear reactor, coupling with the phenomena of heat conduction in the rod and thermal-hydraulics in the cooling fluid, via the reactivity feedback. Firstly, a mesh convergence and turbulence model study was performed, using the Reynolds-Average Navier-Stokes method, with square arrayed rod bundle featuring pitch to diameter ratio of 1:32. Secondly, simulations using the k-! SST turbulence model were performed with an axial distribution of the power generation in the fuel to analyse the heat transfer through the gap and cladding, and its in fluence on the thermal-hydraulics behaviour of the cooling fluid. The wall shear stress distribution for the centre-line rods and the dimensionless velocity were evaluated to validate the model, as well as the in fluence of the mass flow rate variation on the friction factor. The coupled model enabled to perform a dynamic analysis of the nuclear reactor during events of insertion of reactivity and shutdown of primary coolant pumps. (author)

  14. A correlation-based pulse detection technique for gamma-ray/neutron detectors

    International Nuclear Information System (INIS)

    Faisal, Muhammad; Schiffer, Randolph T.; Flaska, Marek; Pozzi, Sara A.; Wentzloff, David D.

    2011-01-01

    We present a correlation-based detection technique that significantly improves the probability of detection for low energy pulses. We propose performing a normalized cross-correlation of the incoming pulse data to a predefined pulse template, and using a threshold correlation value to trigger the detection of a pulse. This technique improves the detector sensitivity by amplifying the signal component of incoming pulse data and rejecting noise. Simulation results for various different templates are presented. Finally, the performance of the correlation-based detection technique is compared to the current state-of-the-art techniques.

  15. Amino acids analysis using grouping and parceling of neutrons cross sections techniques; Analise de aminoacidos atraves das tecnicas do agrupamento e parcelamento de secoes de choque para neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Voi, Dante Luiz Voi [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil); Rocha, Helio Fenandes da [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Puericultura e Pediatria Martagao Gesteira

    2002-07-01

    Amino acids used in parenteral administration in hospital patients with special importance in nutritional applications were analyzed to compare with the manufactory data. Individual amino acid samples of phenylalanine, cysteine, methionine, tyrosine and threonine were measured with the neutron crystal spectrometer installed at the J-9 irradiation channel of the 1 kW Argonaut Reactor of the Instituto de Engenharia Nuclear (IEN). Gold and D{sub 2}O high purity samples were used for the experimental system calibration. Neutron cross section values were calculated from chemical composition, conformation and molecular structure analysis of the materials. Literature data were manipulated by parceling and grouping neutron cross sections. (author)

  16. A novel Fe–Cr–Nb matrix composite containing the TiB{sub 2} neutron absorber synthesized by mechanical alloying and final hot isostatic pressing (HIP) in the Ti-tubing

    Energy Technology Data Exchange (ETDEWEB)

    Litwa, Przemysław [Department of Advanced Materials and Technologies, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland); Perkowski, Krzysztof [Department of Nanotechnology, Institute of Ceramics and Building Materials, Postępu 9, 02-676 Warsaw (Poland); Zasada, Dariusz [Department of Advanced Materials and Technologies, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland); Kobus, Izabela; Konopka, Gustaw [Department of Nanotechnology, Institute of Ceramics and Building Materials, Postępu 9, 02-676 Warsaw (Poland); Czujko, Tomasz [Department of Advanced Materials and Technologies, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland); Varin, Robert A., E-mail: robert.varin@uwaterloo.ca [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave., Waterloo, ON N2L 3G1 (Canada)

    2016-07-25

    The Fe–Cr–Ti-Nb elemental powders were mechanically alloyed/ball milled with TiB{sub 2} and a small quantity of Y{sub 2}O{sub 3} ceramic to synthesize a novel Fe-based alloy-ceramic powder composite that could be processed by hot isostatic pressing (HIP) for a perceived potential application as a neutron absorber in nuclear reactors. After ball milling for the 30–80 h duration relatively uniform powders with micrometric sizes were produced. With increasing milling time a fraction of TiB{sub 2} particles became covered with the much softer Fe-based alloy which resulted in the formation of a characteristic “core-mantel” structure. For the final HIP-ing process the mechanically alloyed powders were initially uniaxially pressed into rod-shaped compacts and then cold isostatically pressed (CIP-ed). Subsequently, the rod-shaped compacts were placed in the Ti-tubing and subjected to hot isostatic pressing (HIP) at 1150 °C/200 MPa pressure. The HIP-ing process resulted in the formation of the near-Ti and intermediate diffusional layers in the microstructure of HIP-ed samples which formed in accord with the Fe-Ti binary phase diagram. Those layers contain the phases such as α-Ti (HCP), the FeTi intermetallic and their hypo-eutectoid mixtures. In addition, needle-like particles were formed in both layers in accord with the Ti-B binary phase diagram. Nanohardness testing, using a Berkovich type diamond tip, shows that the nanohardness in the intermediate layer areas, corresponding to the composition of the hypo-eutectoid mixture of Ti-FeTi, equals 980.0 (±27.1) HV and correspondingly 1176.9 (±47.6) HV for the FeTi phase. The nanohardness in the sample's center in the areas with the fine mixture of Fe-based alloy and small TiB{sub 2} particles equals 1048.3 (±201.8) HV. The average microhardness of samples HIP-ed from powders milled for 30 and 80 h is 588 HV and 733 HV, respectively. - Highlights: • A Fe–Cr–Nb-based composite with TiB{sub 2} neutron

  17. Nondestructive analysis of the natural uranium mass through the measurement of delayed neutrons using the technique of pulsed neutron source; Analise nao destrutiva da massa de uranio natural atraves da medida de neutrons atrasados com o uso da tecnica de fonte pulsada de neutrons rapidos

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Paulo Rogerio Pinto

    1979-07-01

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

  18. Velocity field measurement in gas-liquid metal two-phase flow with use of PIV and neutron radiography techniques

    International Nuclear Information System (INIS)

    Saito, Y.; Mishima, K.; Tobita, Y.; Suzuki, T.; Matsubayashi, M.

    2001-01-01

    Neutron radiography and PIV (Particle Image Velocimetry) techniques were applied to measurements of velocity field in gas-liquid metal two-phase flow. Visualization and measurements of two-phase flow were conducted using molten lead bismuth and nitrogen gas as working fluids and particles made of gold-cadmium (AuCd 3 ) inter-metallic alloy were employed as the tracer. Discrimination method between bubble and tracer images in two-phase flow was developed based on the σ-scaling method. Time-averaged liquid velocity fields, gas velocity fields and void profile were calculated from discriminated images, respectively. From these measurements, the basic characteristics of gas-liquid metal two-phase mixture were clarified. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Nohtomi, Akihiro, E-mail: nohtomi@hs.med.kyushu-u.ac.jp [Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan); Kurihara, Ryosuke; Kinoshita, Hiroyuki; Honda, Soichiro; Tokunaga, Masaaki; Uno, Heita [Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan); Shinsho, Kiyomitsu [Graduate School of Human Sciences, Tokyo Metropolitan University, 7-2-10 Higashi-oku, Arakawa-ku, Tokyo 116-8551 (Japan); Wakabayashi, Genichiro [Atomic Energy Research Institute, Kinki University, 3-4-1 Kowakae, Higashiosaka-shi, Osaka 577-8502 (Japan); Koba, Yusuke [National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555 (Japan); Fukunaga, Junichi; Umezu, Yoshiyuki; Nakamura, Yasuhiko [Department of Radiology, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan); Ohga, Saiji [Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582 (Japan)

    2016-10-01

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

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  1. Effects of neutron irradiation on optical and chemical properties of CR-39: Potential application in neutron dosimetry.

    Science.gov (United States)

    Sahoo, G S; Paul, S; Tripathy, S P; Sharma, S C; Jena, S; Rout, S; Joshi, D S; Bandyopadhyay, T

    2014-12-01

    Effects of high-dose neutron irradiation on chemical and optical properties of CR-39 were studied using FTIR (Fourier Transform Infrared) and UV-vis (Ultraviolet-Visible) spectroscopy. The primary goal was to find a correlation between the neutron dose and the corresponding changes in the optical and chemical properties of CR-39 resulted from the neutron irradiation. The neutrons were produced by bombarding a thick Be target with 22-MeV protons. In the FTIR spectra, prominent absorbance peaks were observed at 1735cm(-1) (C=O stretching), 1230cm(-1)(C-O-C stretching), and 783cm(-1)(=C-H bending), the intensities of which decreased with increasing neutron dose. The optical absorbance in the visible range increased linearly with the neutron dose. Empirical relations were established to estimate neutron doses from these optical properties. This technique is particularly useful in measuring high doses, where track analysis with an optical microscope is difficult because of track overlapping. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. What can we learn from the neutron clinical experience for improving ion-beam techniques and high-LET patient selection?

    International Nuclear Information System (INIS)

    Wambersie, A.; Jones, D.T.L.; Gueulette, J.; Gahbauer, R.; DeLuca, P.M.

    2010-01-01

    .e., moving from neutrons to 12 C ions and from photons to protons, respectively). An important area of research involves developing criteria to identify specific patients suitable for high-LET radiation. One promising technique is to measure the RBE of the cancer cell population in vitro mainly in head and neck tumors. Modern molecular imaging allows the identification of hypoxic or proliferative regions in the tumor. Special MRI examinations are also able to identify hypoxic regions. A promising predictive test recently initiated, is the study of non-repairable double strand breaks but the utility of the technique needs to be confirmed. The extensive experience with fast neutron therapy can greatly assist the transition to high-LET charged-particle therapy.

  3. Shining a light on Jarosite: formation, alteration and stability studies using in situ experimental synchrotron and neutron techniques.

    Science.gov (United States)

    Brand, H. E. A.; Scarlett, N. V. Y.; Wilson, S. A.; Frierdich, A. J.; Grey, I. E.

    2016-12-01

    Jarosites and related minerals are critical to a range of mineral processing and research applications. They are used in the removal of iron species from smelting processes; they occur in metal bioleaching systems, and they are present in acid mine drainage environments. There has been a recent resurgence in interest in jarosites since their detection on Mars. In this context, the presence of jarosite has been recognised as a likely indicator of liquid water at the surface of Mars in the past & it is thought that their study will provide insight into the environmental history of Mars. Acid sulfate soils cover large areas of the Australian coastline and are likely to be a major constituent of the Martian environment. The oxidation of acid sulfate soils, coupled with potential release of heavy metals and acidic groundwaters, can have serious consequences for fragile ecosystems. Understanding these sediments will provide insight into the biogeochemical processes that affect the lifetimes of transient mineral species on Earth, and may be used to better understand soil acidification, contaminant mobility at sites affected by acid and metalliferous drainage, and even constrain past weathering and putative biosignatures on Mars. Knowledge of the behaviour of jarosite minerals under the actual conditions that they are found in is crucial to understanding their potential environmental impacts on both Earth and Mars. To this end, we are engaged in a program to study the formation, stability and alteration of natural and synthetic jarosite minerals using a complementary suite of in situ synchrotron and neutron techniques. There are 3 sections to this work that will introduce the experimental techniques and sample environments that make these measurements possible: Studying the nucleation and growth of jarosites under laboratory conditions. The experimentation consisted of time-resolved synchrotron small angle X-ray scattering and X-ray diffraction. Studying the stability of

  4. Gamma, X-ray and neutron techniques for the coal industry

    International Nuclear Information System (INIS)

    1986-01-01

    Nuclear techniques play a prominent role in all aspects of the coal industry, from exploration through mine development to testing of coal quality during production. The advent of on-line nuclear techniques allows continuous, near real time appraisal of coal quality free from the errors inherent in conventional techniques based on discrete samples. The Advisory Group Meeting reviews the latest developments in this area and makes recommendations on the most promising areas and priorities for future research and development activities. This report records the proceedings of the Advisory Group Meeting. Separate abstracts were prepared for each of the 13 papers in this report

  5. Using Neutron Scattering and Mercury Intrusion Techniques to Characterize Micro- and Nano-Pore Structure of Shale

    Science.gov (United States)

    Zhang, Y.; Barber, T.; Hu, Q.; Bleuel, M.

    2017-12-01

    The micro- and nano-pore structure of oil shale plays a critical role in hydrocarbon storage and migration. This study aims to characterize the pore structure of three Bakken members (i.e., upper organic-rich shale, middle silty/sandy dolomites, and lower organic-rich shale), through small and ultra-small angle neutron scattering (SANS and USANS) techniques, as well as mercury injection capillary pressure (MICP) analyses. SANS/USANS have the capabilities of measuring total porosity (connected and closed porosity) across nm-mm spectrum, not measurable than other fluid-invasion approaches, such as MICP which obtains connected porosity and pore-throat size distribution. Results from both techniques exhibit different features of upper/lower Bakken and middle Bakken, as a result of various mineral composition and organic matter contents. Middle Bakken is primarily dominated by the mineral pores, while in the upper and lower Bakken, organic pores contribute a significant portion of total porosity. A combination of USANS/SANS and MICP techniques gives a comprehensive picture of shale micro- and nano-pore structure.

  6. Domain wall motion and magnetization reversal processes in a FeSi picture frame single crystal studied by the time-dependent neutron depolarization technique

    International Nuclear Information System (INIS)

    Schaik, F.J. van.

    1979-01-01

    The three dimensional neutron depolarization technique, which gives detailed information about the static properties of ferromagnetic materials, has been extended to a method by means of which the time dependence of magnetic phenomena can be studied. The measurement of the neutron depolarization against time is made possible by applying a periodical magnetic field on the investigated specimen and by continuous sampling of the transmitted neutron intensity in time channels, which are started synchronously with the applied field. The technique has been used in the study of the magnetic domain structure at room temperature of a (010) [001] picture frame FeSi single crystal (3.5 wt.% Si) with outer dimensions of (15 x 10 x 0.26) mm and a frame width of 2.78 mm. (Auth.)

  7. 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.)

  8. Use of the neutron activation technique: soil-plant transfer factor

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Wellington Ferrari da, E-mail: wferrari250@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Programa de Pós-Graduação em Ciências e Técnicas Nucleares; Menezes, Maria Ângela de B.C., E-mail: menezes@cdtn.br [Centro Desenvolvimento da Tecnologia Nuclear (SERTA/CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Serviço de Técnicas Analíticas. Laboratório de Ativação Neutrônica; Marques, Douglas José, E-mail: douglasjmarques81@yahoo.com.br [Universidade José do Rosário Vellano, Alfenas, MG (Brazil). Setor de Olericultura e Experimentação em Agricultura Orgânica

    2017-07-01

    Recent studies have demonstrated the importance of the soil-plant transfer factor in the absorption and translocation of chemical elements, thus, it is possible to evaluate a better decision-making in the consecutive plantations. To determine these values, the content of a chemical element present in the plant or part of it with the total content present in the same soil where it is grown is considered. The objective of this study was to determine the concentrations of the chemical elements present in soil, leaf and grains corn, by neutron activation analysis and to compare the different soil-plant transfer factors. The samples were collected in a property located in the region of Biquinhas, MG, and irradiated in the TRIGA MARK I IPR-R1 CDTN / CNEN nuclear reactor. Thus, the concentrations of Br, Ce Fe, K, La, Na, Rb, Zn were determined. The soil-plant transfer factors for the elements found were varied, indicating a greater potassium absorption capacity (K). (author)

  9. Study of organohalogens in foodstuffs and environmental samples by neutron activation analysis and related techniques

    International Nuclear Information System (INIS)

    Xu, D. D.; Mao, X.Y.; Ouyang, H.; Chai, Z. F.; Zhang, H.; Sun, H. B.

    2004-01-01

    Pine needles and foodstuffs collected from Beijing, China, were analyzed by instrumental neutron activation analysis (INAA) combined with organic solvent extraction for total halogens, extractable organohalogens (EOX) and extractable persistent organohalogens (EPOX). The INAA detection limits are 50 ng, 8 ng and 3.5 ng for Cl, Br and I, respectively. The contents and distribution patterns of organohalogens in these samples are reported. EOCl accounted for 0.013-0.016% and 1.6-2.7% of the total chlorine in yogurt and apples, respectively, which suggested that chlorine in foodstuffs mainly existed as inorganic species and non-extractable organochlorines. EOCl contents in pine needles and foodstuffs were noticeably higher than those of EOBr and EOI. For pine needles, yogurt and apples, 1.6-34%, 23-58% and 29-35% of EOCl remained as extractable persistent organochlorine (EPOCl), respectively. Pine needle containing higher EOCl contents in chemical industrial and traffic hub areas indicated that chemical industries and exhaust emission from vehicle were the main sources of organochlorines in the Beijing's air. The relative proportions of the known organochlorines (such as HCHs, DDTs, chlordanes, heptachlor, HCB and PCBs) to the total EOCl and EPOCl were 0.04-1.6% and 0.7-21.5%, respectively, which implied that the identity of species of a major portion of the EOCl and EPOCl measured in pine needles was unknown. (author)

  10. Use of the neutron activation technique: soil-plant transfer factor

    International Nuclear Information System (INIS)

    Silva, Wellington Ferrari da; Menezes, Maria Ângela de B.C.; Marques, Douglas José

    2017-01-01

    Recent studies have demonstrated the importance of the soil-plant transfer factor in the absorption and translocation of chemical elements, thus, it is possible to evaluate a better decision-making in the consecutive plantations. To determine these values, the content of a chemical element present in the plant or part of it with the total content present in the same soil where it is grown is considered. The objective of this study was to determine the concentrations of the chemical elements present in soil, leaf and grains corn, by neutron activation analysis and to compare the different soil-plant transfer factors. The samples were collected in a property located in the region of Biquinhas, MG, and irradiated in the TRIGA MARK I IPR-R1 CDTN / CNEN nuclear reactor. Thus, the concentrations of Br, Ce Fe, K, La, Na, Rb, Zn were determined. The soil-plant transfer factors for the elements found were varied, indicating a greater potassium absorption capacity (K). (author)

  11. Digital pulse-timing technique for the neutron detector array NEDA

    Energy Technology Data Exchange (ETDEWEB)

    Modamio, V., E-mail: victor.modamio@lnl.infn.it [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Valiente-Dobón, J.J. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Jaworski, G. [Faculty of Physics, Warsaw University of Technology, 00-662 Warszawa (Poland); Heavy Ion Laboratory, University of Warsaw, 02-093 Warszawa (Poland); Hüyük, T. [Instituto de Física Corpuscular, CSIC-Universitat de València, E-46980 Valencia (Spain); Triossi, A. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Egea, J. [Instituto de Física Corpuscular, CSIC-Universitat de València, E-46980 Valencia (Spain); Department of Electronic Engineering, Universitat de València, E-46100 Burjassot (Spain); Di Nitto, A. [Johannes Gutenberg-Universität Mainz, D-55099 Mainz (Germany); Söderström, P.-A. [RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, 351-0198 Saitama (Japan); Agramunt Ros, J. [Instituto de Física Corpuscular, CSIC-Universitat de València, E-46980 Valencia (Spain); Angelis, G. de [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); France, G. de [GANIL, CEA/DSAM and CNRS/IN2P3, F-14076 Caen (France); Erduran, M.N. [Faculty of Engineering and Natural Sciences, Istanbul Sabahattin Zaim University, 34303 Istanbul (Turkey); and others

    2015-03-01

    A new digital pulse-timing algorithm, to be used with the future neutron detector array NEDA, has been developed and tested. The time resolution of four 5 in. diameter photomultiplier tubes (XP4512, R4144, R11833-100, and ET9390-kb), coupled to a cylindrical 5 in. by 5 in. BC501A liquid scintillator detector was measured by employing digital sampling electronics and a constant fraction discriminator (CFD) algorithm. The zero crossing of the CFD algorithm was obtained with a cubic spline interpolation, which was continuous up to the second derivative. The performance of the algorithm was studied at sampling rates of 500 MS/s and 200 MS/s. The time resolution obtained with the digital electronics was compared to the values acquired with a standard analog CFD. The result of this comparison shows that the time resolution from the analog and the digital measurements at 500 MS/s and at 200 MS/s are within 15% for all the tested photomultiplier tubes.

  12. Neutron activation analysis techniques for identifying elemental status in Alzheimer's disease

    International Nuclear Information System (INIS)

    Ward, N.I.; Mason, J.A.

    1986-01-01

    Brain tissue (hippocampus and cerebral cortex) from Alzheimer's disease and control individuals sampled from Eastern Canada and the United Kingdom were analyzed for Ag, Al, As, B, Br, Ca, Cd, Co, Cr, Cs, Cu, Fe, Hg, I, K, La, Mg, Mn, Mo, Ni, Rb, S, Sb, Sc, Se, Si, Sn, Sr, Ti, V and Zn. Neutron activation analysis (thermal and prompt gamma-ray) methods were used. Very highly significant differences (S**: probability less than 0.005) for both study areas were shown between Alzheimer's disease (AD) and control (C) individuals: AD>C for Al, Br, Ca and S, and AD< C for Se, V and Zn. Aluminium content of brain tissue ranged form 3.605 to 21.738 μg/g d.w. (AD) and 0.379 to 4.768 μg/g d.w. (C). No statistical evidence of aluminium accumulation with age was noted. Possible zinc deficiency (especially for hippocampal tissue), was observed with zinc ranges of 31.42 to 57.91 μg/g d.w. (AD) and 37.31 to 87.10 μg/g d.w. (C), for Alzheimer's disease patients. (author)

  13. The industrial uses of neutrons

    International Nuclear Information System (INIS)

    Johnson, M.W.

    1994-01-01

    This paper deals with the neutron scattering and radiography techniques that have been used to solve industrial problems. Over the last ten years the application of neutron techniques to industrial problems has grown as neutron techniques have evolved to study ever more complex systems. The problems raised by industry use a wide spectrum of the neutron scattering techniques available, although some techniques are used frequently - especially for studying residual stress, Small Angle Neutron Scattering (SANS) for studying large scale structures, reflectometry and radiography. This paper reviews the techniques involved and illustrates the new problems that are now being solved using accelerator-based pulsed neutron scattering techniques.(author), 26 refs., 8 figs

  14. Measurement of the magnetic moment of the 2$^{+}$ state in neutron-rich radioactive $^{72,74}$Zn using the transient field technique in inverse kinematics

    CERN Multimedia

    Kruecken, R; Speidel, K; Voulot, D; Neyens, G; Gernhaeuser, R A; Fraile prieto, L M; Leske, J

    We propose to measure the sign and magnitude of the g-factors of the first 2$^{+}$ states in radioactive neutron-rich $^{72,74}$Zn applying the transient field (TF) technique in inverse kinematics. The result of this experiment will allow to probe the $\

  15. Thorium: one of the analytical techniques in neutronic activation and alpha spectrometry of the CDTN (Brazilian Nuclear Technology Development Center) in the last three decades

    International Nuclear Information System (INIS)

    Menezes, M.A.B.C.; Sabino, C.V.S.

    1994-01-01

    For long years, the CDTN (Brazilian Nuclear Technology Development Center ) has applied several analytical techniques in the thorium determination. This work is about the evolution of the neutronic activation in the thorium 232 analysis from the 1960's to now. The importance of the analysis request and alpha spectrometry for the thorium 228 and thorium 232 determination is emphasized. (J.A.M.M.)

  16. Proposal of requirements for performance in Brazil for systems of external individual monitoring for neutrons applying the TLD-albedo technique

    International Nuclear Information System (INIS)

    Martins, Marcelo M.; Mauricio, Claudia L.P.; Pereira, Walsan W.; Fonseca, Evaldo S. da; Silva, Ademir X.

    2009-01-01

    This work presents a criteria and conditions proposal for the regulations in Brazil of individual monitoring systems for neutrons applying the albedo technique with thermoluminescent detectors. Tests are proposed for the characterization performance of the system based on the Regulation ISO 21909 and on the experience of the authors

  17. Determination of REEs in agricultural soils of Pernambuco by the Neutron Activation Technique

    Energy Technology Data Exchange (ETDEWEB)

    França, Fernanda Cláudia S.S.; Ticianelli, Regina Beck; Moreira, Edson Gonçalves; Genezini, Frederico Antonio; Albuquerque, Adriana Muniz de Almeida; Silveira, Patrícia Brandão da; Barbosa, Jonnas Thiago de Lima; Almeida, Amanda Correia de; Honorato, Eliane Valentim; Hazin, Clovis Abrahão, E-mail: nanda_lq@hotmail.com, E-mail: valentim@cnen.gov.br, E-mail: emoreira@ipen.br [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil); Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Centro Regional de Ciências Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2017-11-01

    The indiscriminate use of phosphate fertilizers causes adverse effects on biota, mainly due to the contaminants present in the rocks used in their manufacture. Among these contaminants, stand out the Rare Earth Elements (REEs) because of the significant increase in the use in several technological areas, such as in vehicle catalysts and also in fertilizer enrichment. In order to evaluate the levels of La, Sm, Nd, Yb and Lu by the Instrumental Neutron Activation Analysis (INAA), the present study aims to survey the ETRs in agricultural soils in Pernambuco/Brazil. For this study, 120 soil samples with a depth of 20 cm were collected in the main vegetable producing regions of the Metropolitan Region of Recife (RMR), evaluating organic and conventional crops with and without influenced by automotive vehicles. The results obtained when compared to the Netherlands reference values defined by the National Institute of Health and Environment (RIVM). The results were higher in all points for La (35 mg.kg-¹ at 85 mg.kg-¹) Yb, (4 mg.kg-¹ at 11 mg.kg-¹) and Lu (0.3 mg.kg-¹ at 0.7 mg.kg-¹ at 4 mg.kg-¹). For Nd (9 mg.kg-¹ at 137 mg.kg-¹) the concentrations were above the values reported by RIVM in 4 points. Comparing the types of crops evaluated with the literature, the results are found was above for all elements analyzed. It may be related to the increase in the use of phosphate fertilizers. However, in environments using smaller amounts of additives, the results were also significant and the more detailed studies are needed to evaluate other possible contamination pathways. (author)

  18. Compact ion chamber based neutron detector

    Science.gov (United States)

    Derzon, Mark S.; Galambos, Paul C.; Renzi, Ronald F.

    2015-10-27

    A directional neutron detector has an ion chamber formed in a dielectric material; a signal electrode and a ground electrode formed in the ion chamber; a neutron absorbing material filling the ion chamber; readout circuitry which is electrically coupled to the signal and ground electrodes; and a signal processor electrically coupled to the readout circuitry. The ion chamber has a pair of substantially planar electrode surfaces. The chamber pressure of the neutron absorbing material is selected such that the reaction particle ion trail length for neutrons absorbed by the neutron absorbing material is equal to or less than the distance between the electrode surfaces. The signal processor is adapted to determine a path angle for each absorbed neutron based on the rise time of the corresponding pulse in a time-varying detector signal.

  19. Measurement/Evaluation Techniques and Nuclear Data Associated with Fission of 239Pu by Fission Spectrum Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Baisden, P; Bauge, E; Ferguson, J; Gilliam, D; Granier, T; Jeanloz, R; McMillan, C; Robertson, D; Thompson, P; Verdon, C; Wilkerson, C; Young, P

    2010-03-16

    This Panel was chartered to review and assess new evaluations of work on fission product data, as well as the evaluation process used by the two U.S. nuclear weapons physics laboratories. The work focuses on fission product yields resulting from fission spectrum neutrons incident on plutonium, and includes data from measurements that had not been previously published as well as new or revised fission product cumulative yield data, and related quantities such as Q values and R values. This report documents the Panel's assessment of the work presented by Los Alamos National Laboratory (LANL) and Lawrence Livermore National Laboratory (LLNL). Based on the work presented we have seven key observations: (1) Experiments conducted in the 1970s at LANL, some of which were performed in association with a larger, NIST-led, program, have recently been documented. A preliminary assessment of this work, which will be referred to in this document as ILRR-LANL, shows it to be technically sound. (2) LLNL has done a thorough, unbiased review and evaluation of the available literature and is in the process of incorporating the previously unavailable LANL data into its evaluation of key fission product yields. The results of the LLNL effort, which includes a preliminary evaluation of the ILRR-LANL data, have been documented. (3) LANL has also conducted an evaluation of fission product yields for fission spectrum neutrons on plutonium including a meta-analysis of benchmark data as part of a planned upgrade to the ENDF/B compilation. We found that the approach of using meta-analysis provides valuable additional insight for evaluating the sparse data sets involved in this assessment. (4) Both laboratories have provided convincing evidence for energy dependence in the fission product yield of {sup 147}Nd produced from the bombardment of {sup 239}Pu with fission spectrum neutrons over an incident neutron energy range of 0.2 to 1.9 MeV. (5) Consistent, complete, and explicit treatment

  20. Additive manufacturing of RF absorbers

    Science.gov (United States)

    Mills, Matthew S.

    The ability of additive manufacturing techniques to fabricate integrated electromagnetic absorbers tuned for specific radio frequency bands within structural composites allows for unique combinations of mechanical and electromagnetic properties. These composites and films can be used for RF shielding of sensitive electromagnetic components through in-plane and out-of-plane RF absorption. Structural composites are a common building block of many commercial platforms. These platforms may be placed in situations in which there is a need for embedded RF absorbing properties along with structural properties. Instead of adding radar absorbing treatments to the external surface of existing structures, which adds increased size, weight and cost; it could prove to be advantageous to integrate the microwave absorbing properties directly into the composite during the fabrication process. In this thesis, a method based on additive manufacturing techniques of composites structures with prescribed electromagnetic loss, within the frequency range 1 to 26GHz, is presented. This method utilizes screen printing and nScrypt micro dispensing to pattern a carbon based ink onto low loss substrates. The materials chosen for this study will be presented, and the fabrication technique that these materials went through to create RF absorbing structures will be described. The calibration methods used, the modeling of the RF structures, and the applications in which this technology can be utilized will also be presented.

  1. Neutron diffraction

    International Nuclear Information System (INIS)

    James, M.; Howard, C.J.; Kennedy, S.

    1999-01-01

    Diffraction methods, especially X-ray diffraction, are widely used in materials science. Neutron diffraction is in many ways similar to X-ray diffraction, but is also complementary to the X-ray technique so that in some cases it yields information not accessible using X-rays. Successes of neutron diffraction include the elucidation of the crystal structures of high temperature superconductors and materials that display colossal magnetoresistance, the phase analysis of zirconia engineering ceramics, in depth stress determination in composites, successful determination of the structures of metal hydrides, transition metal polymer complexes and the determination of magnetic structure. A brief description of current studies, using neutron diffraction is given

  2. Residual stress distribution in austenitic stainless steel pipe butt-welded joint measured by neutron diffraction technique

    International Nuclear Information System (INIS)

    Maekawa, Akira; Noda, Michiyasu; Oumaya, Toru; Takahashi, Shigeru

    2009-01-01

    Residual stress is inevitable consequence of welding or manufacturing process, which might greatly affect propagation of high-cycle fatigue or SCC crack. In order to evaluate damages due to the crack, it is required to estimate residual stress and to reflect them to the evaluation process as well. The magnitude and distribution of residual stress greatly depend on the individual process of welding or manufacturing, while the accuracy of prediction or measurement is still insufficient. This paper reports the result of residual stress measurement of butt-welded pipe made of austenitic stainless steel. It also intended to improve prediction and measurement techniques concerning to residual stress. The measurement was conducted by neutron diffraction technique employing the diffractometer for residual stress analysis developed by Japan Atomic Energy Agency. The measured results showed typical characteristics of butt-welded pipe both in decline of stress along axial direction and in radial distribution of bending due to axial stress. The measured result agreed qualitatively with the result predicted by the finite element analysis. A quantitative comparison between measured result and analysis showed a shift of the measured stress toward higher tensile. The measured result was also compared with the results by X-ray diffraction and strain-gauge methods to grasp the distinctive results of the methods. (author)

  3. Design and building of a homemade sample changer for automation of the irradiation in neutron activation analysis technique

    International Nuclear Information System (INIS)

    Gago, Javier; Hernandez, Yuri; Baltuano, Oscar; Bedregal, Patricia; Lopez, Yon; Urquizo, Rafael

    2014-01-01

    Because the RP-10 research reactor operates during weekends, it was necessary to design and build a sample changer for irradiation as part of the automation process of neutron activation analysis technique. The device is formed by an aluminum turntable disk which can accommodate 19 polyethylene capsules, containing samples to be sent using the pneumatic transfer system from the laboratory to the irradiation position. The system is operate by a control switchboard to send and return capsules in a variable preset time and by two different ways, allowing the determination of short, medium and long lived radionuclides. Also another mechanism is designed called 'exchange valve' for changing travel paths (pipelines) allowing the irradiated samples to be stored for a longer time in the reactor hall. The system design has allowed complete automation of this technique, enabling the irradiation of samples without the presence of an analyst. The design, construction and operation of the device is described and presented in this article. (authors).

  4. Asymmetric distribution of cone-shaped lipids in a highly curved bilayer revealed by a small angle neutron scattering technique.

    Science.gov (United States)

    Sakuma, Y; Urakami, N; Taniguchi, T; Imai, M

    2011-07-20

    We have investigated the lipid sorting in a binary small unilamellar vesicle (SUV) composed of cone-shaped (1,2-dihexanoyl-sn-glycero-3-phosphocholine: DHPC) and cylinder-shaped (1,2-dipalmitoyl-sn-glycero-3-phosphocholine: DPPC) lipids. In order to reveal the lipid sorting we adopted a contrast matching technique of small angle neutron scattering (SANS), which extracts the distribution of deuterated lipids in the bilayer quantitatively without steric modification of lipids as in fluorescence probe techniques. First the SANS profile of protonated SUVs at a film contrast condition showed that SUVs have a spherical shape with an inner radius of 190 Å and a bilayer thickness of 40 Å. The SANS profile of deuterated SUVs at a contrast matching condition showed a characteristic scattering profile, indicating an asymmetric distribution of cone-shaped lipids in the bilayer. The characteristic profile was described well by a spherical bilayer model. The fitting revealed that most DHPC molecules are localized in the outer leaflet. Thus the shape of the lipid is strongly coupled with the membrane curvature. We compared the obtained asymmetric distribution of the cone-shaped lipids in the bilayer with the theoretical prediction based on the curvature energy model.

  5. Water utilization of vegetables grown under plastic greenhouse conditions in Ankara using neutron probe technique

    International Nuclear Information System (INIS)

    Halitligil, M.B.; Kislal, H.; Sirin, H.; Sirin, C.; Kilicaslan, A.

    2004-01-01

    In order to find suitable varieties of tomato, pepper and cucumber for plastic greenhouse conditions in Ankara and ensure both higher yields and lower NO 3 leaching greenhouse experiments were conducted for three years. In the first year (2001) of the experiment four different varieties from each vegetable, namely, Tomato (Ecem F 1 , 9920 F 1 , 2116 F 1 and Yazg1 F 1 ), Cucumber (Hizir F 1 , Rapido, Hana, and Luna) and Pepper (1245 F 1 , 730 F 1 , Serademre 8 and 710 F 1 ) had been grown in the plastic greenhouse using drip irrigation-fertilization system. Yazg1 F 1 variety for tomato, Hizir F 1 variety for cucumber and Serademre 8 variety for pepper were chosen to be suitable varieties to grow in the plastic greenhouse conditions in Ankara. One access tube in each N 3 and N 0 treatment plots of tomato, cucumber and pepper in 2002 and 2003 experiments were installed for the soil moisture determinations at 30, 60 and 90 cm depths. Readings with the neutron probe were taken before planting and after harvest for the water consumption calculations using the water balance approach and the WUE was calculated on the basis of the ratio of dry matter weight to the amount of water consumed. Tensiometer and suction cups were installed at 15, 30, 45 and 60 cm depths only to N 1 , N 2 and N 3 treatments plots of each vegetable in 2002 and 2003. Tensiometer readings were taken just before irrigation. Also, soil solution samples from suction cups were taken at final harvest and NO 3 determinations were done with RQFLEX nitrate test strips. Significantly higher yields and WUE values were obtained when the same amount of N fertilizer is applied through fertigation compared to the treatment where N fertilizer applied to the soil then drip irrigated. The nitrate concentrations of the soil solution increased as the N rates increased and no NO 3 had been found in the soil solution taken from 75 cm soil depth, indicating that no leaching of N fertilizer occurred beyond 75 cm soil depth

  6. Water utilization of vegetables grown under plastic greenhouse conditions in Ankara using neutron probe technique

    International Nuclear Information System (INIS)

    Halitligil, M.B.; Kislal, H.; Sirin, H.; Sirin, C.; Kilicaslan, A.

    2004-01-01

    Full text: In order to find suitable varieties of tomato, pepper and cucumber for plastic greenhouse conditions in Ankara and ensure both higher yields and lower NO 3 leaching greenhouse experiments were conducted for three years. In the first year (2001) of the experiment four different varieties from each vegetable, namely, Tomato (Ecem F 1 , 9920 F 1 , 2116 F 1 and Yazg1 F 1 ), Cucumber (Hizir F 1 , Rapido, Hana, and Luna) and Pepper (1245 F 1 , 730 F 1 , Serademre 8 and 710 F 1 ) had been grown in the plastic greenhouse using drip irrigation-fertiligation system. Yazg1 F 1 variety for tomato, Hizir F 1 variety for cucumber and Serademre 8 variety for pepper were chosen to be suitable varieties to grow in the plastic greenhouse conditions in Ankara. One access tube in each N 3 and N 0 treatment plots of tomato, cucumber and pepper in 2002 and 2003 experiments were installed for the soil moisture determinations at 30, 60 and 90 cm depths. Readings with the neutron probe were taken before planting and after harvest for the water consumption calculations using the water balance approach and the WUE was calculated on the basis of the ratio of dry matter weight to the amount of water consumed. Tensiometer and suction cups were installed at 15, 30, 45 and 60 cm depths only to N 1 , N 2 and N 3 treatments plots of each vegetable in 2002 and 2003. Tensiometer readings were taken just before irrigation. Also, soil solution samples from suction cups were taken at final harvest and NO 3 determinations were done with RQFLEX nitrate test strips. Significantly higher yields and WUE values were obtained when the same amount of N fertilizer is applied through fertigation compared to the treatment where N fertilizer applied to the soil then drip irrigated. The nitrate concentrations of the soil solution increased as the N rates increased and no NO 3 had been found in the soil solution taken from 75 cm soil depth, indicating that no leaching of N fertilizer occurred beyond 75 cm

  7. Study of some Ayurvedic Indian medicinal plants for the essential trace elemental contents by instrumental neutron activation analysis and atomic absorption spectroscopy techniques

    International Nuclear Information System (INIS)

    Lokhande, R.S.; Singare, P.U.; Andhele, M.L.; Acharya, R.; Nair, A.G.C.; Reddy, A.V.R.

    2009-01-01

    Elemental analysis of some medicinal plants used in the Indian Ayurvedic system was performed by employing instrumental neutron activation analysis (INAA) and atomic absorption spectroscopy (AAS) techniques. The samples were irradiated with thermal neutrons in a nuclear reactor and the induced activity was counted by gamma ray spectrometry using an efficiency calibrated high resolution high purity germanium (HPGe) detector. Most of the medicinal plants were found to be rich in one or more of the elements under study. The variation in elemental concentration in same medicinal plants samples collected in summer, winter and rainy seasons was studied and the biological effects of these elements on human beings are discussed. (orig.)

  8. $\\beta$-decay study of neutron-rich Tl, Pb, and Bi by means of the pulsed-release technique and resonant laser ionisation

    CERN Multimedia

    Lettry, J

    2002-01-01

    It is proposed to study new neutron-rich nuclei around the Z = 82 magic shell closure, with major relevance for understanding the evolution of nuclear structure at extreme isospin values. Following the IS354 experiment, $\\beta$-decay studies of neutron-rich thallium, lead and bismuth isotopes will be performed for 215 $\\leqslant$ A $\\leqslant$ 219. To this purpose the pulsed-release technique, which was pioneered at ISOLDE, will be optimised. It will be complemented with the higher element selectivity that can be obtained by the unique features of resonant laser ionisation, available at ISOLDE from the RILIS source.

  9. Neutron inelastic scattering studies of crystal hydrates. Part of a coordinated programme on the application of research reactor neutron scattering techniques in the study of solids

    International Nuclear Information System (INIS)

    Amilius, Z.

    1977-12-01

    Using an inverted berillium filter spectrometer, neutrons inelastically scattered from the samples of hydrated and deuterated crystals of Cu Cl 2 .2H 2 O, Cu Cl 2 .2H 2 O and K 2 Cu Cl 2 .2D 2 O were measured, with the objective of determining the librational frequencies of the water molecule. The experiments were performed at room temperature only, permitting to draw only limited conclusions on the assignment of specific librational modes to the peak in the observed neutron spectra

  10. Elemental activation analysis with decay and prompt gamma ray techniques, using isotopic neutron sources and a nuclear research reactor. Part of a coordinated programme on nuclear-based techniques in geology and mineral prospecting

    International Nuclear Information System (INIS)

    El-Kady, A.A.

    1979-05-01

    This is to review the research activities carried out through the IAEA research Project 1697/RB ''Elemental activation analysis with decay and prompt gamma ray techniques, using isotopic neutron sources and the nuclear research reactor. The programme of work includes: a) Development of decay and prompt gamma ray activation techniques for mineral exploration. b) Development of epithermal NAA in addition to thermal NAA especially for gold ore. c) Development of non-destructive insitu elemental analysis with decay and prompt gamma ray techniques using isotopic neutron sources. A joint programme has been established with the Egyptian Geological Surrey and Mining Authority for using nuclear techniques in evaluating gold prospects of several ancient gold mines and investigating several tin-tantalum deposits, which were discovered over the last few years. Two sources of neutrons were used for irradiation, one of the dry channels of the two megawatts research reactor, ET-RR-1 for laboratory studies, and a Pu-Be neutron source in paraffin assembly for possible insitu work

  11. NEUTRON DENSITY CONTROL IN A NEUTRONIC REACTOR

    Science.gov (United States)

    Young, G.J.

    1959-06-30

    The method and means for controlling the neutron density in a nuclear reactor is described. It describes the method and means for flattening the neutron density distribution curve across the reactor by spacing the absorbing control members to varying depths in the central region closer to the center than to the periphery of the active portion of the reactor to provide a smaller neutron reproduction ratio in the region wherein the members are inserted, than in the remainder of the reactor thereby increasing the over-all potential power output.

  12. Determination of Methylmercury Traces in Biological Matrix: Chemical Extraction and Nuclear Quantification with the Neutron Activation Analysis Technique

    International Nuclear Information System (INIS)

    Soldati, A.L.

    2002-01-01

    Mercury is present in the environment as a result of the human and natural activities.The total amount of Hg present in the biosphere has been incremented three times since the industrial era, and now it is affecting in a global sense all the ecosystem.One of the main entrance of Hg in the human diet is the consumption of fish and other marine creatures.Most of the ingested Hg is mono methylmercury (MeHg), which is one of the most toxic forms in which this element could be found because it crosses membranes.Since the toxicity levels are low, the determination of concentrations of total Hg and Me Hg require very careful sampling, sample conditioning and analytical procedures to prevent either losses or contamination, or the degradation of the Hg species.In this work, we implemented a chemical Me Hg extraction procedure, using a ionic exchange resin, with three different types of fish tissue: muscle, liver and hepato pancreas.After Me Hg extraction, the determination and quantification was made by Instrumental Neutron Activation Analysis, by measuring the 197 Au, y el 203 Tl deexcitation s, created through the radioactive decay of the isotopes 197 Hg y 203 Hg.The influence of several parameters on the overall extraction process, such as velocity of passage through the ionic exchange column and the acid concentration used in the extraction was evaluated.Regarding the INAA determinations, a choice was made for the irradiation, decay and counting times, neutron and gamma doses, and the counting geometry The detection limit found for this technique (dry weight) is 140 pg MeHg/g. The Hg contents of the muscle samples were measured with the 279 keV emission of the product of the 202 Hg(n,g) 203 Hg reaction, with a recovery of (100 ± 13)%. Liver and Hepato pancreas samples were measured with the 77 keV gamma emission of the 197 Hg, checking this result with the 67 y 69 keV X emissions from the same isotope.The liver samples needed an extra vacuum filtering process during

  13. Determination of neutron spectra formed by 40-MeV deuteron bombardment of a lithium target with multi-foil activation technique

    CERN Document Server

    Maekawa, F; Wada, M; Wilson, P P H; Ikeda, Y

    2000-01-01

    Neutron flux spectra at an irradiation field produced by a 40-MeV deuteron bombardment on a thick lithium-target at Forschungszentrum Karlsruhe, Germany, have been determined by the multi-foil activation technique. Twenty-seven dosimetry reactions having a wide energy range of threshold energies up to 38 MeV were employed as detectors for the neutron flux spectra extending to 55 MeV. The spectra were adjusted with the SAND-II code with the experimental reaction rates based on an iterative method. The adjusted spectra validated quantitatively the Monte Carlo deuteron-lithium (d-Li) neutron source model code (M sup C DeLi) which was used to calculate initial guess spectra and also has been used for IFMIF nuclear designs. Accuracy of the adjusted spectra was approx 10% that was suitable for successive integral tests of activation cross section data.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-10-15

    One of the key drawbacks to the use of BUNKI code is that the process begins the reconstruction of the spectrum based on a priori knowledge as close as possible to the solution that is sought. The user has to specify the initial spectrum or do it through a subroutine called MAXIET to calculate a Maxwellian and a 1/E spectrum as initial spectrum. Because the application of iterative procedures by to resolve the reconstruction of neutron spectrum needs an initial spectrum, it is necessary to have new proposals for the election of the same. Based on the experience gained with a widely used method of reconstruction, called BUNKI, has developed a new computational tools for neutron spectrometry and dosimetry, which was first introduced, which operates by means of an iterative algorithm for the reconstruction of neutron spectra. The main feature of this tool is that unlike the existing iterative codes, the choice of the initial spectrum is performed automatically by the program, through a neutron spectra catalog. To develop the code, the algorithm was selected as the routine iterative SPUNIT be used in computing tool and response matrix UTA4 for 31 energy groups. (author)

  15. Neutron activation techniques in the detection and measurement of environmental pollutants

    International Nuclear Information System (INIS)

    Spyrou, N.M.; Maheswaran, P.; Nagy, K.; Oezek, F.

    1976-01-01

    The Medical and Environmental Group at the University of Surrey has been involved for several years in the development and application of nuclear activation techniques to biomedical and environmental problems. One such project has been a study of air pollution in the city of Guildford, which requires a routine but quick analytical process for the detection of trace elements in the atmosphere in order to handle data with limited resources and manpower. The proposed method comprises cyclic irradiation and counting, followed by further counting on a low-energy photon detector and a Ge(Li) detector. The scheme concentrates on the measurement of short-lived isotopes. In order to test its efficacy it is compared with conventional activation experiments for irradiation times of 1 min, 10 min and 60 min; various types of filter papers and membranes, used for collection of the samples, are analysed under these conditions. The paper illustrates this comparison by analysis of NBS Standard Reference Material 1571 (Orchard Leaves) on Whatman grade 1 filter paper. The analysis of a typical Guildford sample is also shown. The technique enhances the detection of 38 Clsup(m)(0.74 s), 207 Pbsup(m)(0.8 s), 20 F(11.56 s), 77 Sesup(m)(17.5 s) and 110 Ag(24.4 s). (author)

  16. Fast-neutron and gamma-ray transmission technique for the on-line determination of moisture in coal and coke

    International Nuclear Information System (INIS)

    Sowerby, B.D.; Millen, M.J.; Rafter, P.T.

    1988-01-01

    A fast neutron and γ-ray transmission technique is being developed for the on-line analysis of moisture. Calculations show that the technique is capable of determining coke moisture to better than 0.2 wt% over a wide range of coke thicknesses. The favoured technique uses a thick Li-glass detector surrounded by a neutron moderator to determine simultaneously the fast neutron and γ-ray intensities. Laboratory measurements on single coke samples showed that moisture can be determined to within 0.2 wt% over the range 3-13 wt% moisture and 300-500 mm thickness. Measurements on a range of coke samples showed that the increase in r.m.s. error due to bound H variations is less than about 0.4 wt% moisture. Applications of the technique, to moisture determination in black and brown coal are also investigated, both by calculation and experiment. Further potential applications of the technique are discussed, including the determination of C in steel. (author)

  17. "m=1" coatings for neutron guides

    DEFF Research Database (Denmark)

    Cooper-Jensen, C.P.; Vorobiev, A.; Klinkby, Esben Bryndt

    2014-01-01

    A substantial part of the price for a neutron guide is the shielding needed because of the gamma ray produced when neutrons are absorbed. This absorption occurs in the coating and the substrate of the neutron guides. Traditional m=1 coatings have been made of Ni and if reflectivity over...... the critical angle of Ni is needed one has used Ni58 or Ni/Ti multilayer coatings. Ni has one of the highest neutron scattering density but it also has a fairly high absorption cross section for cold and thermal neutrons and when a neutron is absorbed it emits a lot of gamma rays, some with energies above 9 Me......V. Materials like diamond and Be have higher neutron scattering density than Ni, have smaller absorption cross section and when a neutron is absorbed they emit much less gamma ray and at lower energies. We present results, both theoretically and experimentally, comparing Ni with Be and preliminary results...

  18. New detectors of neutron, gamma- and X-radiations

    CERN Document Server

    Lobanov, N S

    2002-01-01

    Paper presents new detectors to record absorbed doses of neutron, gamma- and X-ray radiations within 0-1500 Mrad range. DBF dosimeter is based on dibutyl phthalate. EDS dosimeter is based on epoxy (epoxide) resin, while SD 5-40 detector is based on a mixture of dibutyl phthalate and epoxy resin. Paper describes experimental techniques to calibrate and interprets the measurement results of absorbed doses for all detectors. All three detectors cover 0-30000 Mrad measured does range. The accuracy of measurements is +- 10% independent (practically) of irradiation dose rates within 20-2000 rad/s limits under 20-80 deg C temperature

  19. A proposal on evaluation method of neutron absorption performance to substitute conventional neutron attenuation test

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Je Hyun; Shim, Chang Ho [Dept. of Nuclear Engineering, Hanyang University, Seoul (Korea, Republic of); Kim, Sung Hyun [Nuclear Fuel Cycle Waste Treatment Research Division, Research Reactor Institute, Kyoto University, Osaka (Japan); Choe, Jung Hun; Cho, In Hak; Park, Hwan Seo [Ionizing Radiation Center, Nuclear Fuel Cycle Waste Treatment Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Hyun Seo; Kim, Jung Ho; Kim, Yoon Ho [Ionizing Radiation Center, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2016-12-15

    For a verification of newly-developed neutron absorbers, one of guidelines on the qualification and acceptance of neutron absorbers is the neutron attenuation test. However, this approach can cause a problem for the qualifications that it cannot distinguish how the neutron attenuates from materials. In this study, an estimation method of neutron absorption performances for materials is proposed to detect both direct penetration and back-scattering neutrons. For the verification of the proposed method, MCNP simulations with the experimental system designed in this study were pursued using the polyethylene, iron, normal glass and the vitrified form. The results show that it can easily test neutron absorption ability using single absorber model. Also, from simulation results of single absorber and double absorbers model, it is verified that the proposed method can evaluate not only the direct thermal neutrons passing through materials, but also the scattered neutrons reflected to the materials. Therefore, the neutron absorption performances can be accurately estimated using the proposed method comparing with the conventional neutron attenuation test. It is expected that the proposed method can contribute to increase the reliability of the performance of neutron absorbers.

  20. A proposal on evaluation method of neutron absorption performance to substitute conventional neutron attenuation test

    International Nuclear Information System (INIS)

    Kim, Je Hyun; Shim, Chang Ho; Kim, Sung Hyun; Choe, Jung Hun; Cho, In Hak; Park, Hwan Seo; Park, Hyun Seo; Kim, Jung Ho; Kim, Yoon Ho

    2016-01-01

    For a verification of newly-developed neutron absorbers, one of guidelines on the qualification and acceptance of neutron absorbers is the neutron attenuation test. However, this approach can cause a problem for the qualifications that it cannot distinguish how the neutron attenuates from materials. In this study, an estimation method of neutron absorption performances for materials is proposed to detect both direct penetration and back-scattering neutrons. For the verification of the proposed method, MCNP simulations with the experimental system designed in this study were pursued using the polyethylene, iron, normal glass and the vitrified form. The results show that it can easily test neutron absorption ability using single absorber model. Also, from simulation results of single absorber and double absorbers model, it is verified that the proposed method can evaluate not only the direct thermal neutrons passing through materials, but also the scattered neutrons reflected to the materials. Therefore, the neutron absorption performances can be accurately estimated using the proposed method comparing with the conventional neutron attenuation test. It is expected that the proposed method can contribute to increase the reliability of the performance of neutron absorbers

  1. Effective neutron temperature measurements in well moderated reactor by the reactivity coefficient method

    International Nuclear Information System (INIS)

    Raisic, N.; Klinc, T.

    1968-11-01

    The ratio of the reactivity changes of a nuclear reactor produced by successive introduction of two different neutron absorbers in the reactor core, has been measured and information on effective neutron temperature at a particular point obtained. Boron was used as a l/v absorber and cadmium as an absorber sensiti ve to neutron temperature. Effective neutron temperature distribution has been deduced by moving absorbers across the reactor core and observing the corresponding reactivity changes. (author)

  2. Comments on liquid hydrogen absorbers for MICE

    International Nuclear Information System (INIS)

    Green, Michael A.

    2003-01-01

    This report describes the heat transfer problems associated with a liquid hydrogen absorber for the MICE experiment. This report describes a technique for modeling heat transfer from the outside world, to the absorber case and in its vacuum vessel, to the hydrogen and then into helium gas at 14 K. Also presented are the equation for free convection cooling of the liquid hydrogen in the absorber

  3. Procedure for the determination of gap and base ground surface configurations beneath the bottom plate of storage tanks using neutron gauging inspection techniques : including radiation safety procedure and emergency procedure

    International Nuclear Information System (INIS)

    Jaafar Abdullah

    1993-01-01

    The procedure is intended for the neutron gauging inspection of gap between the bottom plate and the foundation of bulk storage tanks, which potentially exhibit uneven sinking of the bottom plate and the foundation. Its describes the requirements for the performance of neutron back scattered inspection techniques (or radiometric non-destructive evaluation techniques), using an isotopic neutron source associated with neutron detecting systems, to detect and size the gap between the bottom plate and the foundations as well as to quantify the presence of hydrogenous materials (e.g. oil or water) underneath the bottom plate. This procedure is not only outline the requirements for the neutron gauging inspection, but also describes the requirements which shall be taken into account in formulating the radiation safety and emergency procedures for the neutron gauging inspection works

  4. Metal and trace element assessment of estuary sediments from Santos, Brazil, by neutron activation and atomic absorption techniques

    International Nuclear Information System (INIS)

    Amorim, Eduardo P.; Favaro, Deborah I.T.; Berbel, Glaucia B.B.; Braga, Elisabete S.

    2007-01-01

    In order to better understanding geochemical and environmental processes and their possible changes due to anthropogenic activities trace metal analyses and their distribution in marine sediments are commonly undertaken. The present study reports result concerning the distribution of some major, trace and rare earth elements in the Santos estuarine marine sediments. Thirteen bottom sediment samples (SV0501 to SV0513) were collected in this estuary, including regions of Sao Vicente, Santos, Cubatao, Vicente de Carvalho and Santos' Bay, in the summer of 2005. Multielemental analysis was carried out by instrumental neutron activation analysis (INAA). For total mercury determination cold vapor atomic absorption technique (CV AAS) was employed. In both cases methodology validation was performed by certified reference material analyses. The results obtained for multielemental concentrations in the sediment samples were compared with NASC (North American Shale Composite) values. The concentration values obtained for As and metals Cr, Hg and Zn in the sediment samples were compared to Canadian Council of Minister of the Environment (CCME) oriented values (TEL and PEL values). In general, the samples located near the Cubatao region showed higher concentrations for all elements analyzed probably due to the high impact of industrial activities. (author)

  5. Metal and trace element assessment of estuary sediments from Santos, Brazil, by neutron activation and atomic absorption techniques

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, Eduardo P.; Favaro, Deborah I.T. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mails: ducamorim@yahoo.com.br; defavaro@ipen.br; Berbel, Glaucia B.B.; Braga, Elisabete S. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. Oceanografico. Lab. de Nutrientes, Micronutrientes e Tracos nos Oceanos - LABNUT]. E-mail: edsbraga@usp.br

    2007-07-01

    In order to better understanding geochemical and environmental processes and their possible changes due to anthropogenic activities trace metal analyses and their distribution in marine sediments are commonly undertaken. The present study reports result concerning the distribution of some major, trace and rare earth elements in the Santos estuarine marine sediments. Thirteen bottom sediment samples (SV0501 to SV0513) were collected in this estuary, including regions of Sao Vicente, Santos, Cubatao, Vicente de Carvalho and Santos' Bay, in the summer of 2005. Multielemental analysis was carried out by instrumental neutron activation analysis (INAA). For total mercury determination cold vapor atomic absorption technique (CV AAS) was employed. In both cases methodology validation was performed by certified reference material analyses. The results obtained for multielemental concentrations in the sediment samples were compared with NASC (North American Shale Composite) values. The concentration values obtained for As and metals Cr, Hg and Zn in the sediment samples were compared to Canadian Council of Minister of the Environment (CCME) oriented values (TEL and PEL values). In general, the samples located near the Cubatao region showed higher concentrations for all elements analyzed probably due to the high impact of industrial activities. (author)

  6. Bend-absorbing clamp

    Science.gov (United States)

    Abbott, J. R.; Valencia, B., Jr.

    1979-01-01

    Compact, inexpensive clamp for flexible cables or rigid tubes absorbs vibrations and other motion. It accomodates wide range of dimensions, and saves space by eliminating pigtails or bellows commonly used to absorb linear movement or vibrations

  7. Assessment of doses due to secondary neutrons received by patient treated by proton therapy; Evaluation des doses dues aux neutrons secondaires recues par les patients traites par protontherapie

    Energy Technology Data Exchange (ETDEWEB)

    Sayah, R.; Martinetti, F.; Donadille, L.; Clairand, I. [Institut de radioprotection et de surete nucleaire (IRSN), BP 17, 92262 Fontenay-aux-Roses, Cedex (France); Delacroix, S.; De Oliveira, A. [Institut Curie-centre de protontherapie d' Orsay (ICPO), Campus universitaire batiment 101, 91898 Orsay (France); Herault, J. [Centre Antoine Lacassagne (CAL), 33, avenue de Valombrose, 06189 Nice Cedex 2 (France)

    2010-07-01

    Proton therapy is a specific technique of radiotherapy which aims at destroying cancerous cells by irradiating them with a proton beam. Nuclear reactions in the device and in the patient himself induce secondary radiations involving mainly neutrons which contribute to an additional dose for the patient. The author reports a study aimed at the assessment of these doses due to secondary neutrons in the case of ophthalmological and intra-cranial treatments. He presents a Monte Carlo simulation of the room and of the apparatus, reports the experimental validation of the model (dose deposited by protons in a water phantom, ambient dose equivalent due to neutrons in the treatment room, absorbed dose due to secondary particles in an anthropomorphic phantom), and the assessment with a mathematical phantom of doses dues to secondary neutrons received by organs during an ophthalmological treatment. He finally evokes current works of calculation of doses due to secondary neutrons in the case of intra-cranial treatments

  8. Adaptive inertial shock-absorber

    International Nuclear Information System (INIS)

    Faraj, Rami; Holnicki-Szulc, Jan; Knap, Lech; Seńko, Jarosław

    2016-01-01

    This paper introduces and discusses a new concept of impact absorption by means of impact energy management and storage in dedicated rotating inertial discs. The effectiveness of the concept is demonstrated in a selected case-study involving spinning management, a recently developed novel impact-absorber. A specific control technique performed on this device is demonstrated to be the main source of significant improvement in the overall efficiency of impact damping process. The influence of various parameters on the performance of the shock-absorber is investigated. Design and manufacturing challenges and directions of further research are formulated. (paper)

  9. Prototype Stilbene Neutron Collar

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, M. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Shumaker, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Snyderman, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Verbeke, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wong, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-26

    A neutron collar using stilbene organic scintillator cells for fast neutron counting is described for the assay of fresh low enriched uranium (LEU) fuel assemblies. The prototype stilbene collar has a form factor similar to standard He-3 based collars and uses an AmLi interrogation neutron source. This report describes the simulation of list mode neutron correlation data on various fuel assemblies including some with neutron absorbers (burnable Gd poisons). Calibration curves (doubles vs 235U linear mass density) are presented for both thermal and fast (with Cd lining) modes of operation. It is shown that the stilbene collar meets or exceeds the current capabilities of He-3 based neutron collars. A self-consistent assay methodology, uniquely suited to the stilbene collar, using triples is described which complements traditional assay based on doubles calibration curves.

  10. Neutron scattering techniques for betaine calcium chloride dihydrate under applied external field (temperature, electric field and hydrostatic pressure)

    International Nuclear Information System (INIS)

    Hernandez, O.

    1997-01-01

    We have studied with neutron scattering techniques betaine calcium chloride dihydrate (BCCD), a dielectric aperiodic crystal which displays a Devil's staircase type phase diagram made up of several incommensurate and commensurate phases, having a range of stability very sensitive to temperature, electric field and hydrostatic pressure. We have measured a global hysteresis of δ(T) of about 2-3 K in the two incommensurate phases. A structural study of the modulated commensurate phases 1/4 and 1/5 allows us to evidence that the atomic modulation functions are anharmonic. The relevance of the modelization of the modulated structure by polar Ising pseudo-spins is then directly established. On the basis of group theory calculation in the four dimensional super-space, we interpret this anharmonic modulation as a soliton regime with respect to the lowest-temperature non modulated ferroelectric phase. The continuous character of the transition to the lowest-temperature non modulated phase and the diffuse scattering observed in this phase are accounted for the presence of ferroelectric domains separated by discommensurations. Furthermore, we have shown that X-rays induce in BCCD a strong variation with time of irradiation of the intensity of satellite peaks, and more specifically for third order ones. This is why the 'X-rays' structural model is found more harmonic than the 'neutron' one. Under electric field applied along the vector b axis, we confirm that commensurate phases with δ = even/odd are favoured and hence are polar along this direction. We have evidenced at 10 kV / cm two new higher order commensurate phases in the phase INC2, corroborating the idea of a 'complete' Devil's air-case phase diagram. A phenomenon of generalized coexistence of phases occurs above 5 kV / cm. We have characterized at high field phase transitions between 'coexisting' phases, which are distinguishable from classical lock-in transitions. Under hydrostatic pressure, our results contradict

  11. Long-term clinical outcomes for bifurcation treatment using a provisional T-stenting and double proximal optimization technique with Absorb bioresorbable scaffolds

    Directory of Open Access Journals (Sweden)

    Р. Д. Иванченко

    2017-04-01

    Full Text Available Aim. The article presents long-term outcomes of treatment of coronary artery bifurcation lesions by using bioresorbable vascular scaffolds and provisional T-stenting combined with double proximal optimization. Methods. 14 patients aged 44-80 years (mean age 61±6 years including 8 (57.14 % males underwent endovascular treatment of coronary artery bifurcation lesions by using Absorb bioresorbable vascular scaffolds (BVS. Clinical/instrumental analysis was carried out after 23.7±4.12 months. Angiographic examination was performed in 12 cases (85.71 %. 7 patients (50 % underwent optical coherent tomography. Results. 11 patients (78.57 were free of angina during long-term follow-up. 1 patient (7.14 % developed BVS thrombosis and received a drug-eluting stent. A neointimal layer of the main branch increased during long-term follow-up to 29.23±7.82%, that of the lateral branch – up to 19.2±7.48%. Optical coherence tomography (OCT shows that all strata are fully covered with neointima, the number of strata with malappositions is minimal and the loss of the main branch diameter (16.9±4.9% is insignificant. Conclusion. The use of Absorb bioresorbable vascular scaffolds implanted by means of provisional T-stenting combined with double proximal optimization when treating coronary artery bifurcation lesions is a safe and efficient procedure.Received 2 February 2017. Accepted 10 March 2017.Financing: The study did not have sponsorship.Conflict of interest: The authors declare no conflict of interest.

  12. The study of low-temperature austenite decomposition in a Fe-C-Mn-Si steel using the neutron Bragg edge transmission technique

    International Nuclear Information System (INIS)

    Huang, J.; Vogel, S.C.; Poole, W.J.; Militzer, M.; Jacques, P.

    2007-01-01

    A new technique based on the study of the transmitted neutron beam has been developed to study the low-temperature decomposition of austenite in a 0.4 wt.% C-3 wt.% Mn-2 wt.% Si steel. Experiments were conducted in which the neutron beam continuously passed through a specially designed layered sample, the temperature of which could be controlled to allow for a high-temperature austenization treatment followed by accelerated cooling to an isothermal transformation temperature in the range of 275-450 deg. C. It was possible to measure the volume fraction of the face-centred cubic (fcc) and body-centred cubic (bcc) phases and the carbon concentration of the fcc phase by characterizing the neutron Bragg edges in the transmitted beam. This provides a technique for in situ continuous measurements on the decomposition of austentite. The technique has been validated by comparing the data with other experimental techniques such as dilatometry, quantitative optical metallography and room temperature X-ray diffraction

  13. Water fugacity in absorbing polymers.

    Science.gov (United States)

    Burg, K J; Shalaby, S W

    1997-01-01

    Absorbable biomaterials, as dynamic systems, require special handling, processing, and characterization techniques beyond those of the traditional nonabsorbable materials. As the material degrades or absorbs, in vitro or in vivo, it undergoes structural, physical, and chemical changes. These changes in the base material may significantly impact the performance of a particular biomedical device; hence, it is important that the investigator consider the full range of properties that constitute the lifetime of a given absorbable material. The long term degradation study presented here sought to identify one such property, the change in water retention of a degrading oriented polylactide film. The investigation found through differential scanning calorimetry that later stages of degradation are often characterized by a stronger retention of water, potentially due to a higher number of polar carboxyl groups within the relatively hydrophobic polymer matrix.

  14. Advances in neutron tomography

    Indian Academy of Sciences (India)

    Up to now the interaction of the neutron spin with magnetic fields in samples has not been applied to imaging techniques despite the fact that it was proposed many years ago. About ten years ago neutron depolarization as imaging signal for neutron radiography or tomography was demonstrated and in principle it works.

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

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, M. T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bentoumi, G. [Canadian Nuclear Labs., Chalk River, ON (Canada); Corcoran, E. C. [Royal Military College of Canada, Kingston, ON (United States); Dimayuga, I. [Canadian Nuclear Labs., Chalk River, ON (Canada); Kelly, D. G. [Royal Military College of Canada, Kingston, ON (United States); Li, L. [Canadian Nuclear Labs., Chalk River, ON (Canada); Sur, B. [Canadian Nuclear Labs., Chalk River, ON (Canada); Rogge, R. B. [Canadian Nuclear Labs., Chalk River, ON (Canada)

    2015-11-17

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

  16. Comments on liquid hydrogen absorbers for MICE

    Energy Technology Data Exchange (ETDEWEB)

    Green, Michael A.

    2003-02-01

    This report describes the heat transfer problems associatedwith a liquid hydrogen absorber for the MICE experiment. This reportdescribes a technique for modeling heat transfer from the outside world,to the abosrber case and in its vacuum vessel, to the hydrogen and theninto helium gas at 14 K. Also presented are the equation for freeconvection cooling of the liquid hydrogen in the absorber.

  17. Neutron physics

    International Nuclear Information System (INIS)

    Beckurts, K.H.; Wirtz, K.

    1974-01-01

    This textbook consists of four sections which deal with the following subjects: 1. Production of neutrons and their interactions with the nuclei; neutron sources; neutron detectors; cross-section measurements. 2. Theory of neutron interactions with macroscopic media; neutron slowing down; space distribution of moderated neutrons; neutron thermalization; neutron scattering. 3. Radioactive probe measurements of thermal neutron fluxes; activation by means of epithermal neutrons; threshold detectors of fast neutrons; neutron calibration. 4. Neutron energy; slowing down kernels; neutron age; diffusion length and absorption of neutrons

  18. An appraisal of neutron activation analysis and other analytical techniques for the determination of arsenic, selenium and tin in environmental samples

    International Nuclear Information System (INIS)

    Peterson, P.J.; Girling, C.A.; Klumpp, D.W.; Minski, M.J.

    1979-01-01

    The paper presents an experimental comparison between neutron activation analysis, atomic absorption spectrophotometry and fluorescence spectrophotometry used for the determination of trace amounts of As, Se and Sn and the other two analytical techniques mentioned. Gamma-ray spectrometry has been used to determine 76 As (tsub(1/2)=26.3 h) after 1 day's irradiation at a thermal neutron flux of 1.6x10 12 n.cm -2 .s -1 . High sensitivity was also obtained using an atomic absorption spectrophotometer coupled with covalent hydride generation. Advantages of the latter technique include simplicity of operation, high speed of analysis and negligible background correction. When used in conjuction with selective reduction and a cold-trap this method quantitatively distinguishes between the valence states and some methylated derivatives. Selenium has been analysed by gamma-ray spectrometry using 77 Sesup(m) (tsub(1/2)=17.5 s) after cyclic activation at a thermal neutron flux of 2x10 12 n.cm -2 .s -1 . Atomic absorption spectrophotometry following hydride generation, or fluorescence spectrophotometry of the 2,3 diaminonaphthalene complex constitute additional sensitive analytical methods for the determination of Se. These have the added advantage that valence states can be selectively measured. Low concentrations of Sn have been determined by neutron activation analysis and by spectrophotometric techniques using phenylfluorone as the complexing reagent, but these methods depend on selective extraction of Sn(IV) iodide. Whilst maintaining high sensitivity, these problems were avoided by using the hydride generation technique with an atomic absorption spectrophotometer. Comparative analytical values for Bowen's kale and NBS orchard leaves are presented

  19. Strčess-induced martensitic transformation in Cu-Al-Zn-Mn polycrystal investigated by two in -situ neutron diffraction techniques

    Czech Academy of Sciences Publication Activity Database

    Šittner, Petr; Lukáš, Petr; Neov, Dimitar; Daymond, M. R.; Novák, Václav; Swallowe, G. M.

    2002-01-01

    Roč. 324, - (2002), s. 225-234 ISSN 0921-5093 R&D Projects: GA MŠk ME 186; GA ČR GV202/97/K038; GA AV ČR IAA1010909 Institutional research plan: CEZ:AV0Z1010914 Keywords : Stress-induced martensitic transformation * Cu-Al-Zn-Mn polycrystal * neutron diffraction technique Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.107, year: 2002

  20. Neutron radiography

    International Nuclear Information System (INIS)

    Pugliesi, R.; Freitas, A.G. de; Gammal, A.; Rizzatti, M.R.; Vercelli, P.

    1990-01-01

    The objective was to demonstrate the main characteristics of the neutron radiography technique, which has been developed in the Nuclear Physics Department of the IPEN-CNEN-SP. Its employment, in technology varies enormously and includes among others, the inspection of the hydrogen-rich substances, highly radioactive materials, etc. The indirect conversion method with Dysprosium screen was employed. The experimental arrangement used was a neutron collimator installed in the bottom of the IEA-R1 Nuclear Research Reactor pool. Several samples were analysed which were exposed in a neutron flux ∼ 10 7 n/s.cm 2 during 10 minutes. The obtained results confirm the main characteristics of this technique as well as its viability to be developed in this reactor. (author)

  1. 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.

  2. Detection of spallation neutrons and protons using the natCd activation technique in transmutation experiments at Dubna

    International Nuclear Information System (INIS)

    Manolopoulou, M.; Stoulos, S.; Fragopoulou, M.; Brandt, R.; Westmeier, W.; Krivopustov, M.; Sosnin, A.; Zamani, M.

    2006-01-01

    Various spallation sources have been used to transmute long-lived radioactive waste, mostly making use of the wide energy neutron fluence. In addition to neutrons, a large number of protons and gamma rays are also emitted from these sources. In this paper nat Cd is proved to be a useful activation detector for determining both thermal-epithermal neutron as well as secondary proton fluences. The fluences measured with nat Cd compared with other experimental data and calculations of DCM-DEM code were found to be in reasonable agreement. An accumulation of therma-epithermal neutrons around the center of the target (i.e. after approx. 10 cm) and of secondary protons towards the end of the target is observed

  3. Neutron-emission measurements at a white neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Haight, Robert C [Los Alamos National Laboratory

    2010-01-01

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

  4. Monte Carlo calculation of the slow neutron background in the neutron-neutron scattering experiment at the pulse reactor BIGR

    International Nuclear Information System (INIS)

    Budnik, A.D.; Ososkov, G.A.; Pokotilovskij, Yu.N.; Rogov, A.D.

    1995-01-01

    Slow neutron background calculations were performed for the proposed geometry of the neutron-neutron scattering experiment at the BIGR pulse reactor. The incoming slow neutron space and spectral distributions on the moderator surface were calculated with the MCNP program starting from the exact physical model of the reactor fuel and moderator and shielding geometry. Two elastic scatterings of slow neutrons from the neutron absorbing cover (Cd) inside the collimating and shielding system were taken into account. The calculated thermal neutron background is significantly lower than the estimated n-n scattering effect. 3 refs., 5 figs., 2 tabs

  5. Assessment of doses due to secondary neutrons received by patient treated by proton therapy

    International Nuclear Information System (INIS)

    Sayah, R.; Martinetti, F.; Donadille, L.; Clairand, I.; Delacroix, S.; De Oliveira, A.; Herault, J.

    2010-01-01

    Proton therapy is a specific technique of radiotherapy which aims at destroying cancerous cells by irradiating them with a proton beam. Nuclear reactions in the device and in the patient himself induce secondary radiations involving mainly neutrons which contribute to an additional dose for the patient. The author reports a study aimed at the assessment of these doses due to secondary neutrons in the case of ophthalmological and intra-cranial treatments. He presents a Monte Carlo simulation of the room and of the apparatus, reports the experimental validation of the model (dose deposited by protons in a water phantom, ambient dose equivalent due to neutrons in the treatment room, absorbed dose due to secondary particles in an anthropomorphic phantom), and the assessment with a mathematical phantom of doses dues to secondary neutrons received by organs during an ophthalmological treatment. He finally evokes current works of calculation of doses due to secondary neutrons in the case of intra-cranial treatments

  6. Neutron monitoring for radiological protection

    International Nuclear Information System (INIS)

    Gibson, J.A.B.

    1985-01-01

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

  7. Behaviour Of Saline Irrigation Water Components In Pakistani Barley And Calcareous Soil Under Scheduling Irrigation Using Neutron Scattering Technique

    International Nuclear Information System (INIS)

    RIZK, M.A.

    2010-01-01

    This study aims to investigate the behaviour of cation uptake by Pakistani barley (genotype PK-30163) as affected by saline irrigation water, as well as cation distribution within the soil profile. This experiment was carried out at Soil and Water Research Department, Nuclear Research Centre, Atomic Energy Authority, Inshas, Egypt. The soil was transferred from Wadi Sudr (South Sinai, Egypt). It is salted affected soil (calcareous soil, EC = 4.3 dS/m) and was irrigated using ground water irrigation (12.5 dS/m). Nine used lysimeters were irrigated with three artificial saline water (0.3, 4 and 8 dS/m) using drip irrigation system. The irrigation schedule was carried out using neutron scattering technique according to the hydro physical properties of the soil. Pakistani barley (halophytic plant) was used to remove salts from the soil especially sodium cations. The cation uptake and cation distribution (Na, K, Ca, Mg) within the soil profile were studied.The data indicated that roots of barley collected within 0-15 cm layer showed high cation uptake that made the salt concentrations in this layer low. Sodium uptake ratio was 43, 37 and 47% from total cation uptake by using fresh water (0.3 dS/m), 4 and 8 dS/m, respectively. The maximum uptake for Na, K, Ca and Mg was 20.51, 19.13, 3.98 and 12.81 g/lys at 5.69, 3.05, 6.56 and 4.15 dS/m, respectively. It was found that Pakistani barley preferred Mg uptake rather than Ca uptake.

  8. The r.b.e. of different-energy neutrons as determined by human bone-marrow cell-culture techniques

    International Nuclear Information System (INIS)

    Boeyum, A.; Carsten, A.L.; Chikkappa, G.; Cook, L.; Bullis, J.; Honikel, L.; Cronkite, E.P.

    1978-01-01

    The effect of X-rays and different-energy neutrons on human bone-marrow cells was studied using two different cell-culture techniques - diffusion chamber (DC) growth and colony formation in vitro (CFU-C). Based on the survival and proliferative granulocytes in DC on day 13, the D 0 value was 80 rad with X-rays, and 117 rad as measured by the CFU-C assay. The D 0 values for neutrons depended on the radiation source and the energy level. The r.b.e. values, which dropped with increasing energy levels of mono-energetic neutrons, were (i) 0.44 MeV; DC 3.7, CFU-C 4.1; (ii) 6 MeV; DC 1.8, CFU-C 2.0; (iii) 15 MeV; DC 1.6, CFU-C 1.6; (iv) fission neutrons; DC 2.6, CFU-C 2.4. (author)

  9. The Atomic Fingerprint: Neutron Activation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Keisch, Bernard [Carnegie-Mellon University

    1972-01-01

    The nuclei of atoms are stable only when they contain certain numbers of neutrons and protons. Since nuclei can absorb additional neutrons, which in many cases results in the conversion of a stable nucleus to a radioactive one, neutron activation analysis is possible.

  10. Dosimetry and biological effects of fast neutrons

    International Nuclear Information System (INIS)

    Zoetelief, J.

    1981-01-01

    This thesis contains studies on two types of cellular damage: cell reproductive death and chromosome aberrations induced by irradiation with X rays, gamma rays and fast neutrons of different energies. A prerequisite for the performance of radiobiological experiments is the determination of the absorbed dose with a sufficient degree of accuracy and precision. Basic concepts of energy deposition by ionizing radiation and practical aspects of neutron dosimetry for biomedical purposes are discussed. Information on the relative neutron sensitivity of GM counters and on the effective point of measurement of ionization chambers for dosimetry of neutron and photon beams under free-in-air conditions and inside phantoms which are used to simulate the biological objects is presented. Different methods for neutron dosimetry are compared and the experimental techniques used for the investigations of cell reproductive death and chromosome aberrations induced by ionizing radiation of different qualities are presented. Dose-effect relations for induction cell inactivation and chromsome aberrations in three cultured cell lines for different radiation qualities are presented. (Auth.)

  11. Neutron diffraction

    International Nuclear Information System (INIS)

    Howard, C.J.; Kennedy, S.J.

    1994-01-01

    A brief account is given of neutron diffraction techniques. Similarities and differences compared with the more familiar X-ray counterparts are discussed. In certain applications, neutron diffraction can be used to obtain information about materials which would be difficult or even impossible to obtain using other techniques. One spectacular success has been the elucidation, from neutron powder diffraction, of the crystal structures of high critical temperature oxide superconductors. There have been substantial contributions in other fields, and these are illustrated by Australian work. The ability of the neutron to penetrate deeply into most materials has been invoked for in-depth determination of stresses in composites and of phase composition in zirconia ceramics. The unique properties of the neutron have been successfully exploited in studies of metal hydrides, to determine where hydrogen is located, and in magnetic structure determination. There is much interest in studying materials under different conditions of temperature and pressure, and kinetic studies under such conditions are now becoming possible. The article includes information on the principles, the instrumentation with particular reference to the instruments installed around the HIFAR reactor at Lucas Heights, and methods for the interpretation of data. 59 refs., 3 tabs., 16 figs

  12. FOREWORD: Neutron metrology Neutron metrology

    Science.gov (United States)

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

    2011-12-01

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

  13. Neutrons and materials

    International Nuclear Information System (INIS)

    Paulus, W.; Meinnel, J.

    2003-01-01

    The neutron is the only probe that gives information simultaneously on structure issues through interference phenomena and on dynamics issues through spectroscopy. The neutron carries a s=1/2 spin value which allows it to be polarizable and to interact with any magnetic field through the magnetic momentum associated to its spin. The great interest of neutron in research relies on 3 facts: -) the neutron fluxes used to study matter are supplied by nuclear reactors and spallation sources with wave lengths and energy range that directly correspond to interatomic distances and thermal-motion energies of matter, -) the possibility of setting or changing the contrast of an element by using its different isotopes, and -) the neutron does not carry an electrical charge so it can enter the bulk of matter easily and gives an image of stress and patterns of large pieces of metal through a non-destructive examination. This course reviews all the aspects of the use of neutron in physics and is made up of 16 chapters: 1) properties of neutrons, 2) neutron production, 3) complementarity between X-ray and neutrons, 4) neutron diffraction, 5) neutron diffusion, 6) neutron spectroscopy, 7) crystallography, 8) imaging techniques with neutrons, 9) neutron activation analysis, 10) low-angle diffusion, 11) neutron reflectivity, 12) non-destructive testing, 13) microstructure and diffraction rays of X-radiation, 14) access to neutron source facilities, 15) composites materials and neutron diffusion, and 16) studies of liquids and glasses through neutron and X-ray diffraction. (A.C.)

  14. Determination of the archaeological origin of ceramic fragments characterized by neutron activation analysis, by means of the application of multivariable statistical analysis techniques

    International Nuclear Information System (INIS)

    Almazan T, M. G.; Jimenez R, M.; Monroy G, F.; Tenorio, D.; Rodriguez G, N. L.

    2009-01-01

    The elementary composition of archaeological ceramic fragments obtained during the explorations in San Miguel Ixtapan, Mexico State, was determined by the neutron activation analysis technique. The samples irradiation was realized in the research reactor TRIGA Mark III with a neutrons flow of 1·10 13 n·cm -2 ·s -1 . The irradiation time was of 2 hours. Previous to the acquisition of the gamma rays spectrum the samples were allowed to decay from 12 to 14 days. The analyzed elements were: Nd, Ce, Lu, Eu, Yb, Pa(Th), Tb, La, Cr, Hf, Sc, Co, Fe, Cs, Rb. The statistical treatment of the data, consistent in the group analysis and the main components analysis allowed to identify three different origins of the archaeological ceramic, designated as: local, foreign and regional. (Author)

  15. Development of technique for high-pressure single-crystal neutron scattering and its application to studies of magnetic materials

    International Nuclear Information System (INIS)

    Osakabe, Toyotake

    2012-01-01

    In this article, a new high-pressure apparatus for single-crystal magnetic neutron diffraction under 10 GPa is described. First, new hybrid-anvil, which is composed of an opposed pair of a supported SiC anvil and a tungsten carbide (WC) anvil with a center-dimpled culet, is introduced. Next, results of an investigation of pressure-transmitting media are shown. The hydrostaticity of the media is essential for the single-crystal diffraction experiments. Finally, a thermal neutron focusing device with a lot of curved supermirrors is shown. The device can compensate weak magnetic signals from tiny samples in high-pressure cells. As examples of the studies using the apparatus, the high-pressure single-crystal magnetic neutron diffraction experiments on 4f-electron systems PrFe 4 P 12 and HoB 2 C 2 are taken up. (author)

  16. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Hudelot, J.P

    1998-06-19

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

  19. Feasibility of complementary use of neutron and X-ray scattering techniques in research of lipid mixtures

    International Nuclear Information System (INIS)

    Hirai, Mitsuhiro

    2007-01-01

    It is well recognized that the complementary use of X-ray and neutron small-angle scattering methods serve us fruitful information on nano-scale structures of materials at different phases, especially for systems composed of different components in solutions. This report briefly reviews some recent applications of X-ray and neutron scattering methods of the solutions of lipid mixtures composed of glycosphingolipid, cholesterol and phospholipid. The applications presented here would be very useful and feasible for studies of membrane interfaces in many cases. One of the most promising methods, called s pin contrast variation , is also introduced in comparison with other conventional methods

  20. 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)

  1. Fundamental physics research and neutron interferometry

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-08-01

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

  2. Fundamental of neutron radiography and the present of neutron radiography in Japan

    International Nuclear Information System (INIS)

    Sekita, Junichiro

    1988-01-01

    Neutron radiography refers to the application of transmitted neutrons to analysis. In general, thermal neutron is used for neutron radiography. Thermal neutron is easily absorbed by light atoms, including hydrogen, boron and lithium, while it is not easily absorbed by such heavy atoms as tungsten, lead and uranium, permitting detection of impurities in heavy metals. Other neutrons than thermal neutron can also be applied. Cold neutron is produced from fast neutron using a moderator to reduce its energy down to below that of thermal neutron. Cold neutron is usefull for analysis of thick material. Epithermal neutron can induce resonance characteristic of each substance. With a relatively small reaction area, fast neutron permits observation of thick samples. Being electrically neutral, neutrons are difficult to detect by direct means. Thus a substance that releases charged particles is put in the path of neutrons for indirect measurement. X-ray film combined with converter screen for conversion of neutrons to charge particles is placed behind the sample. Photographing is carried out by a procedure similar to X-ray photography. Major institues and laboratories in Japan provided with neutron radiography facilities are listed. (Nogami, K.)

  3. Neutron diffraction

    International Nuclear Information System (INIS)

    Elcomb, M.M.

    2002-01-01

    Full text: Thermal neutrons have a particular combination of properties, which make them the probe of choice for a wide range of scattering applications. They penetrate most materials easily, the wavelength matches interatomic spacings, the energy matches the atomic vibrational energies and the magnetic moment allows them to uniquely interact with magnetic structures. Their widely varying scattering length is also used to advantage. It enables the determination of light atoms in the presence of heavy ones: hydrogen in organic molecules, and oxygen in the high Tc superconductors for example, or solving problems in alloy systems where distinction of atoms, which are neighbours in the periodic table, is required. In the 50 years since thermal neutron beams have been used for research there has been a steady increase in applications as technology has advanced. This also applies to the environments in which the materials are studied. In-situ studies at other than ambient temperatures, pressures and magnetic fields are now routine. By using multiple detector channels in powder instruments the data collection rate has increased by an order of magnitude to some extent compensating for the diffuse nature of the neutron source. The applications of neutron scattering are becoming more industrially oriented. The talk will highlight the complementarity of neutrons to other more readily available techniques, and give examples of recent research and applications. Copyright (2002) Australian X-ray Analytical Association Inc

  4. Investigation of conformal and intensity-modulated radiation therapy techniques to determine the absorbed fetal dose in pregnant patients with breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Öğretici, Akın, E-mail: akinogretici@gmail.com; Akbaş, Uğur; Köksal, Canan; Bilge, Hatice

    2016-07-01

    The aim of this research was to investigate the fetal doses of pregnant patients undergoing conformal radiotherapy or intensity-modulated radiation therapy (IMRT) for breast cancers. An Alderson Rando phantom was chosen to simulate a pregnant patient with breast cancer who is receiving radiation therapy. This phantom was irradiated using the Varian Clinac DBX 600 system (Varian Medical System, Palo Alto, CA) linear accelerator, according to the standard treatment plans of both three-dimensional conformal radiation therapy (3-D CRT) and IMRT techniques. Thermoluminescent dosimeters were used to measure the irradiated phantom's virtually designated uterus area. Thermoluminescent dosimeter measurements (in the phantom) revealed that the mean cumulative fetal dose for 3-D CRT is 1.39 cGy and for IMRT it is 8.48 cGy, for a pregnant breast cancer woman who received radiation treatment of 50 Gy. The fetal dose was confirmed to increase by 70% for 3-D CRT and 40% for IMRT, if it is closer to the irradiated field by 5 cm. The mean fetal dose from 3-D CRT is 1.39 cGy and IMRT is 8.48 cGy, consistent with theoretic calculations. The IMRT technique causes the fetal dose to be 5 times more than that of 3-D CRT. Theoretic knowledge concerning the increase in the peripheral doses as the measurements approached the beam was also practically proven.

  5. Bench-Top Antigen Detection Technique that Utilizes Nanofiltration and Fluorescent Dyes which Emit and Absorb Light in the Near Infrared

    Science.gov (United States)

    Varaljay-Spence, Vanessa A.; Scardelletti, Maximilian C.

    2007-01-01

    This article discusses the development of a bench-top technique to detect antigens in fluids. The technique involves the use of near infrared NIR fluorescent dyes conjugated to antibodies, centrifugation, nanofilters, and spectrometry. The system used to detect the antigens utilizes a spectrometer, fiber optic cables, NIR laser, and laptop computer thus making it portable and ideally suited for desk top analysis. Using IgM as an antigen and the secondary antibody, anti-IgM conjugated to the near infrared dye, IRDye (trademark) 800, for detection, we show that nanofiltration can efficiently and specifically separate antibody-antigen complexes in solution and that the complexes can be detected by a spectrometer and software using NIR laser excitation at 778 nm and NIR dye offset emission at 804 nm. The peak power detected at 778 nm for the excitation emission and at 804 nm for the offset emission is 879 pW (-60.06 dBm) and 35.7 pW (-74.5 dBm), respectively.

  6. Neutron scatter camera

    Science.gov (United States)

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

    2010-06-22

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

  7. Improving differential die-away analysis via the use of neutron poisons in detectors

    International Nuclear Information System (INIS)

    Jordan, Kelly A.; Vujic, Jasmina; Phillips, Emmanuel; Gozani, Tsahi

    2007-01-01

    Differential Die-Away Analysis (DDAA) is an active interrogation technique to detect special nuclear material (SNM). In DDAA, a pulsed neutron generator produces pulses of neutrons that are directed into a cargo to be interrogated. As each pulse passes through the cargo, the neutrons are thermalized and absorbed. If SNM is present, the thermalized neutrons from the source will cause fissions that produce a new source of neutrons. The number of thermal neutrons decay exponentially with the diffusion decay time of the inspected medium, on the order of hundreds of μs. An external neutron detector which is designed to detect only epithermal neutrons, will measure only a single decaying exponential when there is no SNM present, and two exponentials when SNM is present. This paper shows that in many cases, a gain in detection sensitivity can be realized by introducing a thermal neutron poison (such as boron) into the detector. This poison will reduce the efficiency of the detector, but decrease its decay time. A decreased decay time will cause the separation between the detector and fission signal exponentials to occur at an earlier time. There is a balance between efficiency and time constant for a detector. The boron concentration to achieve the maximum sensitivity, and its magnitude, will be different for different detector designs

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-03-01

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

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

    DEFF Research Database (Denmark)

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

    1984-01-01

    Diffraction and coherent diffuse quasielastic scattering of neutrons have been used to investigate Frenkel disorder of the oxygen sublattice in single crystals of stoichiometric UO2. Measurements were made up to 2900 K using a special high-temperature furnace. The results provide the first direct...

  10. Three-dimensional absorbed dose determinations by N.M.R. analysis of phantom-dosemeters

    International Nuclear Information System (INIS)

    Gambarini, G.; Birattari, C.; Fumagalli, M.L.; Vai, A.; Monti, D.; Salvadori, P.; Facchielli, L.; Sichirollo, A.E.

    1996-01-01

    Magnetic resonance imaging of a tissue-equivalent phantom is a promising technique for three-dimensional determination of absorbed dose from ionizing radiation. A reliable method of determining the spatial distribution of absorbed dose is indispensable for the planning of treatment in the presently developed radiotherapy techniques aimed at obtaining high energy selectively delivered to cancerous tissues, with low dose delivered to the surrounding healthy tissue. Aqueous gels infused with the Fricke dosemeter (i.e. with a ferrous sulphate solution), as proposed in 1984 by Gore et al., have shown interesting characteristics and, in spite of some drawbacks that cause a few limitations to their utilisation, they have shown the feasibility of three-dimensional dose determinations by nuclear magnetic resonance (NMR) imaging. Fricke-infused agarose gels with various compositions have been analysed, considering the requirements of the new radiotherapy techniques, in particular Boron Neutron Capture Therapy (B.N.C.T.) and proton therapy. Special attention was paid to obtain good tissue equivalence for every radiation type of interest. In particular, the tissue equivalence for thermal neutrons, which is a not simple problem, has also been satisfactorily attained. The responses of gel-dosemeters having the various chosen compositions have been analysed, by mean of NMR instrumentation. Spectrophotometric measurements have also been performed, to verify the consistence of the results. (author)

  11. Archaeology benefits from neutron tomography investigations in South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Beer, F.C. de [Radiation Sciences, Research and Development, Necsa (South Africa)], E-mail: Frikkie.DeBeer@necsa.co.za; Botha, H. [South African Institute for Objects Conservation, Twee Riviere, Eastern Cape (South Africa); Ferg, E. [Department of Chemistry, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Grundlingh, R. [South African Institute for Objects Conservation, Twee Riviere, Eastern Cape (South Africa); Smith, A. [National Cultural History Museum, Pretoria (South Africa)

    2009-06-21

    This paper describes the neutron tomography investigation on archaeological artifacts from museums in South Africa. While X-rays fail to penetrate the brass matrix of the samples, neutrons can easily reveal, on a non-invasive manner, the content and structure of these precious samples. The South African Neutron Radiography (SANRAD) facility, located at the SAFARI-1 nuclear research reactor, operated by Necsa near Pretoria, South Africa, was utilized in a tomography mode during the investigations. For the 3D tomographical reconstruction of the sample, 375 projections were collected while the sample was rotated around a defined axis through 360 deg. rotation interval. The results show that the technique is able to reconstruct structural features very well and in particular, highly absorbing zones and the presence of defects in the bulk. The samples originate from collections at museums in South Africa and these investigations were the first of its kind performed in the country.

  12. Archaeology benefits from neutron tomography investigations in South Africa

    International Nuclear Information System (INIS)

    Beer, F.C. de; Botha, H.; Ferg, E.; Grundlingh, R.; Smith, A.

    2009-01-01

    This paper describes the neutron tomography investigation on archaeological artifacts from museums in South Africa. While X-rays fail to penetrate the brass matrix of the samples, neutrons can easily reveal, on a non-invasive manner, the content and structure of these precious samples. The South African Neutron Radiography (SANRAD) facility, located at the SAFARI-1 nuclear research reactor, operated by Necsa near Pretoria, South Africa, was utilized in a tomography mode during the investigations. For the 3D tomographical reconstruction of the sample, 375 projections were collected while the sample was rotated around a defined axis through 360 deg. rotation interval. The results show that the technique is able to reconstruct structural features very well and in particular, highly absorbing zones and the presence of defects in the bulk. The samples originate from collections at museums in South Africa and these investigations were the first of its kind performed in the country.

  13. Advances in analytical techniques for neutron capture therapy: thin layer chromatography matrix and track etch thin layer chromatography methods for boron-10 analysis

    International Nuclear Information System (INIS)

    Schremmer, J.M.; Noonan, D.J.

    1987-01-01

    A new track etch autoradiographic technique for quantitating boron-10 containing compounds used for neutron capture therapy is described. Instead of applying solutions of Cs2B12H11SH and its oxidation products directly to solid-state nuclear track detectors, diethylaminoethyl cellulose thin layer chromatography (TLC) plates are utilized as sample matrices. The plates are juxtaposed with Lexan polycarbonate detectors and irradiated in a beam of thermal neutrons. The detectors are then chemically etched, and the resultant tracks counted with an optoelectronic image analyzer. Sensitivity to boron-10 in solution reaches the 1 pg/microliter level, or 1 ppb. In heparinized blood samples, 100 pg boron-10/microliter are detected. This TLC matrix method has the advantage that sample plates can be reanalyzed under different reactor conditions to optimize detector response to the boron-10 carrier material. Track etch/TLC allows quantitation of the purity of boron neutron capture therapy compounds by utilizing the above method with TLC plates developed in solvent systems that resolve Cs2B12H11SH and its oxidative analogs. Detectors irradiated in juxtaposition to the thin layer chromatograms are chemically etched, and the tracks are counted in the sample lane from the origin of the plate to the solvent front. A graphic depiction of the number of tracks per field yields a quantitative analysis of compound purity

  14. Safety techniques in the change of nuclear systems. Radiation protection at spallation neutron sources and transmutation facilities

    International Nuclear Information System (INIS)

    Nuenighoff, Kay

    2009-01-01

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

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

    International Nuclear Information System (INIS)

    Jacquelyn Yanch

    2006-01-01

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

  16. Elemental investigation of (Al-Cu) alloys and some geological samples using neutron activation and XRF analysis techniques

    International Nuclear Information System (INIS)

    Hammad, E.A.M.

    2012-01-01

    Neutron activation analysis (NAA) using k 0 - standardization (k 0 -NAA) is well known method for multi-elemental analysis. The method is used to analyze different samples belonging to different fields. In addition, X- ray fluorescence (XRF) is also used for multi-elemental analysis. XRF complements NAA methods. Both methods were used for investigation of some iron ores and aluminum- cupper alloy (Al-Cu) samples. Elemental concentration of Iron ores and Al-Cu alloy samples were determined by k 0 - NAA and XRF methods. The iron ore samples were collected from Wadi Kareim and Umm Nar sites (the Eastern desert of Egypt). Six and two samples representing the ores of Wadi Kareim and Umm Nar, respectively altogether with the standard samples consisting of Fe, Au , Zr and W and the certified reference sample IAEA Soil-7 were irradiated in one of the irradiated boxes at the Second Egyptian Research Reactor (ETRR- 2). The induced activities were counted using an efficiency calibrated HPGe detector systems. The neutron spectrum parameters α and f characterizing the neutron irradiation position that are needed in applying k 0 -NAA method were determined using the activation product of Zr , Au, Fe and W and found α≅ - 0.048 ±0.002 and f ≅ 38± k 0 -NAA method was applied to determine the elemental concentrations in the two iron ore samples. The concentrations determined were found to vary erratically form one sample to another. The results were discussed and compared with similar results in literature. The accuracy of the k 0 - NAA method was checked by determining the elemental concentration in the IAEA-Soil 7 reference sample. The obtained results are compared with the recommended values. Good agreements were found within 10 %. Short time neutron activation analysis (STNAA) was carried out to determine concentration of major elements in Al-Cu alloy samples. Three (Al-Cu) alloys samples with different concentrations of Cu (2, 3.5 and 5 %) altogether. Au standard sample

  17. A European neutron dosimetry intercomparison project (ENDIP). Results and evaluation

    International Nuclear Information System (INIS)

    Broerse, J.J.; Burger, G.; Coppola, M.

    1978-01-01

    A total of twenty groups from nine countries participated in sessions of the European Neutron Dosimetry Intercomparison Project (ENDIP) which were held during 1975 at GSF, Munich-Neuherberg and TNO, Rijswijk. The data of all participants are collected, the analysis and evaluation of the results are given in the present report. Specific chapters deal with the experimental arrangements and monitoring results at GSF and TNO, characteristics of the dosimetry systems employed by the paticipating groups and the basic physical data and correction factors employed for the determination of kerma and absorbed dose. In general, the participants in ENDIP quote systematic uncertainties of 7 to 8% in the neutron and total kerma or absorbed dose, which are mainly attributed to inadequate knowledge of basic constants. The variations in the results obtained by different participants seem to be in accordance with the relative large systematic uncertainties quoted. In order to determine the influence of the use of different values for the physical parameters, the relative responses of the participants' dosimeters have also been compared. The variances of quoted kerma and dose values are of the same order of magnitude as those of instrument responses. This result indicates inconsistencies in experimental techniques employed by the participants for the determination of kerma and absorbed dose. A separate nonparametric analysis of the ENDIP results confirmed that there are considerable systematic differences. Recommendations for future studies on neutron dosimetry for biological and medical applications are given at the end of the report

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

    CERN Document Server

    Hughes, D J; Heeley, E L

    2014-01-01

    Whilst the structural integrity and lifetime considerations in welded joints for blanket modules can be predicted using finite element software, it is essential to prove the validity of these simulations. This paper provides detailed analysis for the first time, of the residual stress state in a laser-welded sample with integral cooling channels. State-of-the-art non-destructive neutron diffraction was employed to determine the triaxial stress state and to understand microstructural changes around the heat affected zone. Synchrotron X-ray diffraction was used to probe the variation of strain-free lattice reference parameter around the weld zone allowing correction of the neutron measurements. This paper details an important experimental route to validation of predicted stresses in complex safety-critical reactor components for future applications.

  19. Absorber manufacturing made easy

    Energy Technology Data Exchange (ETDEWEB)

    Berner, Joachim

    2010-07-01

    Whether by means of a laser source or an ultrasound head - automation technology is making progress in the solar thermal sector. S and WE presents news developments in welding technology in absorber manufacture. (orig.)

  20. PWR burnable absorber evaluation

    International Nuclear Information System (INIS)

    Cacciapouti, R.J.; Weader, R.J.; Malone, J.P.

    1995-01-01

    The purpose of the study was to evaluate the relative neurotic efficiency and fuel cycle cost benefits of PWR burnable absorbers. Establishment of reference low-leakage equilibrium in-core fuel management plans for 12-, 18- and 24-month cycles. Review of the fuel management impact of the integral fuel burnable absorber (IFBA), erbium and gadolinium. Calculation of the U 3 O 8 , UF 6 , SWU, fuel fabrication, and burnable absorber requirements for the defined fuel management plans. Estimation of fuel cycle costs of each fuel management plan at spot market and long-term market fuel prices. Estimation of the comparative savings of the different burnable absorbers in dollar equivalent per kgU of fabricated fuel. (author)